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In our age of big data and the knowledge society, effective processing and sharing of knowledge is crucial. Agents provide a key abstraction within modern development of artificial intelligence systems and software. In current multi-agent platforms, a simplifying assumption is that all agents use the same symbols to represent their knowledge or expertise. The assumption that agents use the same symbols to represent their knowledge imposes a constraint on system developers and agent systems: agents are forced to use the same ontological representation of the world at the cost of having diverse and unique viewpoints. Furthermore, agents typically exist in dynamic environments that require update and revision of their knowledge and beliefs. We focus on agents that make use of description logic ontologies to represent their knowledge and expertise. Ontologies are knowledge bases consisting of logical statements called axioms. This comes with the advantage that a set of logical axioms can entail knowledge that is not explicitly stated by the axioms: lots of information can be implicit. As a consequence, when communicating, agents must take into account the implicit knowledge contained in their expertise. Assuming a common signature is established between two communicating agents, the agents still require methods to extract specific knowledge from their ontologies that go beyond sending a list of axioms. Agents require methods to extract both explicit and implicit knowledge from their ontologies in a way that can be communicated to another agent if the need arises. This thesis re-uses several existing techniques in the logic literature, mainly uniform interpolation, that can be used to extract knowledge from ontologies and can be adapted for agent communication. In particular, our aim is to develop and evaluate novel algorithms which provide support for scenarios where multiple agents are responsible for different knowledge bases (e.g., that capture the agent's different expertise) and have the ability to restrict (specifically on the basis of uniform interpolation) and adapt their knowledge with respect to the signature of their knowledge base that is shared with other agents. This ensures that knowledge shared is understood by the communication partners. We have realised and developed a range of knowledge extraction methods and structures that enable agents to extract knowledge that can sometimes be implicit with respect to arbitrary subset signatures of their knowledge base. We have analysed and evaluated these knowledge extraction methods on ALC description logic ontologies. Our results suggest that the knowledge extraction methods realised are feasible in some practical settings; unlike the knowledge extraction methods realised, the knowledge extraction methods developed are rarely feasible and useful in practical settings, and will require further exploration and research to be useful in practical settings.

Information gathered socially online is a key feature of the growth and development of modern society. Presently the Internet is a platform for the distribution of data. Millions of people use Online Social Networks daily as a tool to get updated with social, political, educational or other occurrences. In many cases information derived from an Online Social Network is acted upon and often shared with other networks, without further assessments or judgments. Many people do not check to see if the information shared is credible. A user may trust the information generated by a close friend without questioning its credibility, in contrast to a message generated by an unknown user. This work considers the concept of credibility in the wider sense, by proposing whether a user can trust the service provider or even the information itself. Two key components of credibility have been explored; trustworthiness and expertise. Credibility has been researched in the past using Twitter as a validation tool. The research was focused on automatic methods of assessing the credibility of sets of tweets using analysis of microblog postings related to trending topics to determine the credibility of tweets. This research develops a framework that can assist the assessment of the credibility of messages in Online Social Networks. Four types of credibility are explored (experienced, surface, reputed and presumed credibility) resulting in a credibility hierarchy. To determine the credibility of messages generated and distributed in Online Social Networks, a virtual network is created, which attributes nodes with individual views to generate messages in the network at random, recording data from a network and analysing the data based on the behaviour exhibited by agents (an agent-based modelling approach). The factors considered for the experiment design included; peer-to-peer networking, collaboration, opinion formation and network rewiring. The behaviour of agents, frequency in which messages are shared and used, the pathway of the messages and how this affects credibility of messages is also considered. A framework is designed and the resulting data are tested using the design. The resulting data generated validated the framework in part, supporting an approach whereby the concept of tagging the message status assists the understanding and application of the credibility hierarchy. Validation was carried out with Twitter data acquired through twitter’s Application Programming Interface (API). There were similarities in the generation and frequency of the message distributions in the network; these findings were also recorded and analysed using the framework proposed. Some limitations were encountered while acquiring data from Twitter, however, there was sufficient evidence of correlation between the simulated and real social network datasets to indicate the validity of the framework.

This thesis is a contribution to the formalisation of the notion of an agent within the class of finite multivariate Markov chains. In accordance with the literature agents are are seen as entities that act, perceive, and are goaldirected. We present a new measure that can be used to identify entities (called i-entities). The intuition behind this is that entities are spatiotemporal patterns for which every part makes every other part more probable. The measure, complete local integration (CLI), is formally investigated within the more general setting of Bayesian networks. It is based on the specific local integration (SLI) which is measured with respect to a partition. CLI is the minimum value of SLI over all partitions. Upper bounds are constructively proven and a possible lower bound is proposed. We also prove a theorem that shows that completely locally integrated spatiotemporal patterns occur as blocks in specific partitions of the global trajectory. Conversely we can identify partitions of global trajectories for which every block is completely locally integrated. These global partitions are the finest partitions that achieve a SLI less or equal to their own SLI. We also establish the transformation behaviour of SLI under permutations of the nodes in the Bayesian network. We then go on to present three conditions on general definitions of entities. These are most prominently not fulfilled by sets of random variables i.e. the perception-action loop, which is often used to model agents, is too restrictive a setting. We instead propose that any general entity definition should in effect specify a subset of the set of all spatiotemporal patterns of a given multivariate Markov chain. Any such definition will then define what we call an entity set. The set of all completely locally integrated spatiotemporal patterns is one example of such a set. Importantly the perception-action loop also naturally induces such an entity set. We then propose formal definitions of actions and perceptions for arbitrary entity sets. We show that these are generalisations of notions defined for the perception-action loop by plugging the entity-set of the perception-action loop into our definitions. We also clearly state the properties that general entity-sets have but the perception-action loop entity set does not. This elucidates in what way we are generalising the perception-action loop. Finally we look at some very simple examples of bivariate Markov chains. We present the disintegration hierarchy, explain it via symmetries, and calculate the i-entities. Then we apply our definitions of perception and action to these i-entities.

The independent style of scanning and payment at self-service checkouts (SCOs) has resulted in areas for concern. The reduction of employee involvement may reduce the social presence perceived at a SCO. Social presence is when a user experiences the perception that there is another intelligence or entity within their environment (Short, William & Christie, 1976). If customers are not influenced by the social presence of the employees at a SCO then it may affect their behaviour. Using a mixed methods approach, with a combination of qualitative and quantitative data gathering, this thesis investigated dishonest behaviours at self-service checkouts and the effects of a social presence on consumer behaviour. The overreaching research question then guiding this dissertation is: What effect does a social presence have on thefts at self-service checkouts and can social presence be effectively implemented via technology? Three exploratory qualitative (Studies 1-3) and two empirical studies (Studies 4-5) were conducted to investigate issues surrounding thefts at SCO with reference to social presence. Study 1 consisted of in-depth observations of customers within supermarkets to gain an understanding of everyday behaviours associated with self-service checkouts. Both customers and staff seemed to be frustrated at the amount of times the technology did not work properly and the customer would appear disadvantaged when they required assistance. With an understanding of the salient factors and behaviours associated with self-service checkouts, Study 2 then explored SCO staff perceptions of thefts at self-service checkouts (Creighton et al., 2015). Qualitative semi-structured interviews were used to investigate the perceived influence of social presence at self-service checkouts by staff and its perceived effect on dishonest customer behaviour. Twenty-six self-service checkout staff took part in a series of semi-structured interviews to describe customer behaviours with self-service. With respect to actual physical social presence, such as the recognised presence of an employee, staff reported that more customer thefts occurred when the self-service checkouts were busy and their social presence was reduced. To further explore social presence within a retail environment and validate the perceptions from SCO Staff, Study 3 investigated the role of the security guard in terms of their social presence and explored their perceptions of thefts at self-service checkouts. Interviews with 6 security guards were conducted to determine factors surrounding theft as their role is to monitor this type of dishonest behavior. There was an overall agreement from security guards that there were more thefts at self-service checkouts when the store was busy and that there were more thefts at self-service checkouts overall, compared to traditional manned checkouts. The first empirical study (Study 4), consisting of 2 Experiments, considered the effects of a social presence within a self-service checkout interface on user behaviour. This study examined whether a social presence in the form of a computer designed onscreen agent at a simulated SCO, with design features varying in ‘humanness’, i.e. agents that displayed more or less-human-like features (eyes in Experiment 1, and human shapes in Experiment 2), would have an effect on opportunistic behaviour (cheating) in a simulated checkout scenario. Ninety-one participants interacted with a simulated SCO while their eye movements were tracked via a Tobii TX300 eye-tracker. Hypotheses that predicted a social presence would receive attention and result in fewer instances of theft when integrated within an interface were supported, suggesting that implementing an agent designed to suggest some level of humanness e.g. with eyes, within a SCO interface may reduce levels of theft as customers are likely to notice it. However, Study 4 showed mixed results for the effects of varying agent appearance alone. Research has shown that social presence can also be induced by varying agent behaviour (Burgoon et al., 2000). Study 5 thus varied interactivity (i.e. personal vs impersonal nature) of the agent via voice implementation on the SCO, using the same agent as in Study 4 (Experiment 2). The research highlights the need for the current designs of SCO to be updated to reduce operational issues which could be contributing to thefts occurring at SCOs. It is also concluded that further research is needed on the effects of interactivity and agent presence during a SCO interaction to explore dimensions of social presence and how they are being experienced by the user, which may ultimately lead to a reduction in thefts at SCOs.

Smart home systems (SHS) have become an increasingly important technology in modern life. Apart from safety, security, convenience and entertainment, they offer significant potential benefits for the elderly, disabled and others who cannot live independently. Furthermore, smart homes are environmentally friendly. SHS functionality is based on perceiving residents’ needs and desires, then offering services accordingly. In order to be smart, homes have to be equipped with sensors, actuators and intelligent devices and appliances, as well as connectivity and control mechanisms. A typical SHS comprises heterogeneous services and appliances that are designed by many different developers and which may meet for the first time in the home network. The heterogeneous nature of the systems, in addition to the dynamic environment in which they are deployed, exposes them to undesirable interactions between services, known as Feature Interaction (FI). Another reason for FI is the divergence between the policies, needs and desires of different residents. Proposed approaches to FI detection and resolution should take these different types of interaction into account. Negotiation is an effective mechanism to address FI, as conflicting features can then negotiate with each other to reach a compromise agreement. The ultimate goal of this study is to develop an Agent-Based Negotiation Approach (ABNA) to detect and resolve feature interaction in a SHS. A smart home architecture incorporating the components of the ABNA has been proposed. The backbone of the proposed approach is a hierarchy in which features are organised according to their importance in terms of their functional contribution to the overall service. Thus, features are categorised according to their priority, those which are essential for the service to function having the highest priority. An agent model of the ABNA is proposed and comprehensive definitions of its components are presented. A computational model of the system also has been proposed which is used to explain the behaviour of different components when a proposal to perform a task is raised. To clarify the system requirements and also to aid the design and implementation of its properties, a formal specification of the ABNA is presented using the mathematical notations of Calculus of Context-aware Ambient (CCA), then in order to evaluate the approach a case study is reported, involving two services within the SHS: ventilation and air conditioning. For the purpose of evaluation, the execution environment of CCA is utilised to execute and analyse the ABNA.

Characters in games and virtual worlds continue to gain improvements in both their visual appearance and more human-like behaviours with each successive generation of hardware. One area that seemingly would need to be addressed if this evolution in human-like characters is to continue is in the area of characters with emotions. To begin addressing this, the thesis focuses on answering the question “Can an emotional architecture be developed for characters in games and virtual worlds, that is built upon a foundation of formal psychology? Therefore a primary goal of the research was to both review and consolidate a range of background material based on the psychology of emotions to provide a cohesive foundation on which to base any subsequent work. Once this review was completed, a range of supplemental material was investigated including computational models of emotions, current implementations of emotions in games and virtual worlds, machine learning techniques suitable for implementing aspects of emotions in characters in virtual world, believability and the role of emotions, and finally a discussion of interactive characters in the form of chat bots and non-player characters. With these reviews completed, a synthesis of the research resulted in the defining of an emotion architecture for use with pre-existing agent behaviour systems, and a range of evaluation techniques applicable to agents with emotions. To support validation of the proposed architecture three case studies were conducted that involved applying the architecture to three very different software platforms featuring agents. The first was applying the architecture to combat bots in Quake 3, the second to a chat bot in the virtual world Second Life, and the third was to a web chat bot used for e-commerce, specifically dealing with question and answers about the companies services. The three case studies were supported with several small pilot evaluations that were intended to look at different aspects of the implemented architecture including; (1) Whether or not users noticed the emotional enhancements. Which in the two small pilot studies conducted, highlighted that the addition of emotions to characters seemed to affect the user experience when the encounter was more interactive such as in the Second Life implementation. Where the interaction occurred in a combat situation with enemies with short life spans, the user experience seemed to be greatly reduced. (2) An evaluation was conducted on how the combat effectiveness of combat bots was affected by the addition of emotions, and in this pilot study it was found that the combat effectiveness was not quite statistically reduced, even when the bots were running away when afraid, or attacking when angry even if close to death. In summary, an architecture grounded in formal psychology is presented that is suitable for interactive characters in games and virtual worlds, but not perhaps ideal for applications where user interaction is brief such as in fast paced combat situations. This architecture has been partially validated through three case studies and includes suggestions for further work especially in the mapping of secondary emotions, the emotional significance of conversations, and the need to conduct further evaluations based on the pilot studies.

It is recognised that normative systems, and in particular electronic institutions and contracts are a potentially powerful means for making agent interactions in multi-agent systems effective and efficient. However, correctly specifying the behaviour of such systems is a difficult problem. Designers are faced with two concurrent, complex tasks: firstly they must specify the relationships (over time) between agents’ actions and their effects, and secondly they must also consider how agents’ actions are to be regulated through the definition of agents’ permissions and obligations. Such systems are typi- cally complex, and given this complexity it may be difficult for a designer to determine whether their original objectives have been captured by the specification of the system. In this dissertation we seek to address some of the problems associated with institu- tional specification. In order to do this we present a model for specifying institutions based on the notion of socially constructed reality that accounts not only for how the action and events which constitute the institution are described, but also how they are regulated. Institutions may be used in a number of ways, and may account for concepts at varying levels of abstraction. Recognising this we also investigate how several insti- tutions, each accounting for a particular aspect of a society may be composed and how the relationships between these institutions may be expressed. Given this model, we then demonstrate how, using the answer set programming paradigm institutional spec- ifications based on our model may be checked for the absence or presence of certain (un)desirable properties.

The aim of this thesis is to adress the problem of capability brokering. A capability-brokering agent recieves capability advertisements from problem-solving agents and problem descriptions from problem-holding agents. The amin task for the broker is to find problem-solving agents that have the capabilities to address problems described to the broker by a problem-holding agent. Capability brokering poses two problems: for advertisements, and matching problems and capabilities, to find capable problem-solvers. For the representation part of the problem, there have been a number of representations in AI that address similar issues. We review various logical representations, action representations, and representations for models of problem solving and conclude that, while all of these areas have some positive features for the representation of capabilities, they also all have serious drawbacks. We describe a new capability description language, CDL, which shares the positive features of previous languages while avoiding their drawbacks. CDL is a decoupled action representation into which arbitrary state representations can be plugged, resulting in the expressiveness and flexibility needed for capability brokering. Reasoning over capability descriptions takes place on two levels. The outer level deals with agent communication and we have devloped the Knowledge Query and Manipulation Language (KQML) here. At the inner level the main task is to decide whether a capability description subsumes a problem description. In CDL thee subsumtion relation for achievable objectives is defined in terms of the logical entailment relation betwenn sentences in the state language used within CDL. The definition of subsumption for performable tasks in turn is based on this definition for achievable objectives. We describe algoritms in this thesis which have all been implemented and incorporated into he Java Agent Template where they proved sufficient to operationalise anumber of example scenarios. The two most important featues of CDL are its expressiveness and its flexibility. By expressiveness we mean the ability to express more than is possible in other representations. By flexibility we mean the possibility to delay decisions regarding the compromises that have to be made to knowledge representation time. The scenarions we ahve implemted illustrate the importance of the features and we have shown in this thesis that CDL indeed possess thease features. Thus, CDL is an expressive and flexible capability description language that can be used to address the problem of capability brokering.

Pseudomonas aeruginosa displays high levels of tolerance and resistance to many antimicrobial agents. Much of this tolerance is related to the nature of the Gram-negative cell envelope and in particular, the outer membrane. The outer membrane plays an important role in excluding harmful molecules from the cell, whilst being selectively permeable to other solutes via its implanted proteins (outer membrane proteins or OMPs). In order to exert their antibacterial action, antimicrobial agents must enter the cell and attain sufficiently high concentrations at their target site(s). The OMPs are highly sensitive to environmental changes and have a physiological ability to respond to such changes. It is thought that the altered cell envelope structure contributes to the accessibility of antimicrobial agents into the cell interior and resistance to such agents is related to over expression or loss of certain OMPs. Brozel and Cloete (1994) observed a gradual increase in tolerance to increasing concentrations of biocide upon exposure of P. aeruginosa to KathonTM, a commercial biocide containing 1.15% v/v 5-chloro-N-methylisothiazolone (CMIT) and 0.35% v/v N-methylisothiazolone (MIT). This adaptation was associated with the concurrent disappearance of a 35kDa OMP, designated T-OMP. Therefore, they concluded that the biocide entered the sensitive cells via the T-OMP and that the observed resistance was the result of the absence of this OMP. The aim of this investigation was to induce tolerance in cultures of P. aeruginosa PAOl towards the pure active forms of the three isothiazolone biocides 1,2-benzisothiazolone (BIT), MIT, CMIT and the thiol-interactive agent thiomersal (used as a positive control). An increase was observed in the minimum inhibitory concentrations (MIC) of all four biocides by at least 58% between the sensitive and resistant cultures. In some cases the percentage increase in MIC was in excess of 150%. However, when the tolerant cells were removed from the presence of the biocide, the MIC began to decrease, indicating a loss in tolerance. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDSPAGE) analysis of the OMP profiles from the tolerant-induced cultures illustrated the loss of T-OMP in all cases. Analysis of the sensitive and resistant cultures using twodimensional polyacrylamide gel electrophoresis (2D-PAGE) indicated that the T-OMP disappeared in the tolerant cultures. However, these observations also suggested that other outer membrane alterations occur concurrently in T-OMP depleted tolerant cells. Investigations into the cross-resistance of the resistant cultures towards the other test biocides, indicated that resistance was, to some extent, transferable, once it had been developed towards one member of the biocide group. Following routine passaging of the resistant cultures on gradient plates two distinct colonial morphologies were observed, mucoid and non-mucoid. An increase in the cell surface hydrophobicity was noted between the mucoid and non-mucoid cultures, which indicated a loss or reduction in the B-band OPolysaccharide. However, there were no observable differences in the lipopolysaccharide banding patterns between the mucoid and non-mucoid cells. These observations suggested that other alterations were occurring in the tolerant cells upon exposure to biocide, over and above the simple disappearance of T-OMP. Therefore, it is suggested that the observed tolerant development in biocide exposed cells, was not solely due to the loss of T-OMP. Investigations into Gram-negative bacteria isolated from contaminated industrial samples preserved with isothiazolone compounds exhibited higher MICs towards the preservative biocides than would normally be expected in the species of bacteria isolated and identified. However, there were no observable alterations in their OMP profiles.

The purpose of physical thought experiments is to explore the consistency of a physical theory behind it in all possible settings, including scenarios which can be regarded as hypothetical. Some of these scenarios involve agents who can reason based on a given theory, and are also modeled within the same theory; combining the conclusions made by individual agents leads to a logical paradox. This doctoral thesis explores such multi-agent paradoxes inn quantum theory and beyond, the constructions behind them, and their origins. We start with reviewing (in an intuitive way) older instances of paradoxes. In particular, we focus on the famous incompleteness results from mathematics, and outline their construction: the diagonalization theorem, which also happens to be the structure underlying epistemic self-referential paradoxes. We continue with a review of the history of thought experiments in quantum theory, discuss their importance for interpretations of quantum theory, and give an overview of resolutions that were proposed over the years. We proceed to present a software package framework allowing to model quantum thought experiments where agents reason about their knowledge and are also modeled within the theory, with several adaptable modules. Next, we explore other physical theories, such as generalized probabilistic theories, Spekkens' toy model, and the positive formalism of Oeckl, find examples of scenarios like those in quantum theory, and check in which ones a paradox is recovered. Subsequently, we present a more general framework to talk about multi-agent paradoxes in an arbitrary physical theory, and establish a link between paradoxes and contextuality. We also list some properties of paradoxes in quantum theory. Finally, we classify some ``escape strategies'' for avoiding multi-agent paradoxes in physical theories by analyzing the axioms governing agents' knowledge used in the derivation of inconsistencies. We conclude by pointing out future research directions.

There are many different doorways into the world of book publishing and it can be challenging, but there are choices that can make it easier. Aspiring publishers often have a hard time breaking into this world because they have no guide. This thesis will be a guide to traversing the different avenues into the world of publishing. Prospective publishers, editors, and writers will be provided with a landscape of what it’s like to work in book publishing. It will also cover the two different ways that people become publishers, an overview of the basic requirements that publishing houses look for in potential employees, and the basic process of what publishers do.

This article seeks to identify the individuals that took part as witnesses in the pastoral visitations, focusing in the indigenous peoples of the Lima diocese during the 17th century. The main question this article asks is: to what extent the pastoral visitations conducted under colonial rule contributed to shaping local authority structures? We also ask for the characteristics of the individuals summoned by the diocesan inspectors. Were they traditional authorities or were their posts created by the colonial administration? To what extent were they literate and how important was that they had a command of Spanish? Was there a link between literacy, bilingualism and the area within the diocese they belonged to? I argue that since the choice of authorities that spoke on behalf of the parishioners was not solely in the hands of the locals, the Catholic Church must have had a decisive role in deciding who fulfilled the requirements to represent their parishes.

Abstract: Waterflooding is one enhanced oil recovery process used in heavy oil reservoirs such as at Cold Lake in North-Eastern Alberta. However, little has been published in terms of imaging heavy oil waterfloods, mainly due to the similar densities of water and heavy oil, which makes it difficult to track the process by methods such as computer tomography (CT) scanning. This thesis will first present the results of physical and magnetic characterization of four magnetic nanoparticle compositions for potential use as magnetic contrast agent tracers for tracking the waterflooding of a heavy oil saturated sandpack. The magnetic properties of the nanoparticles were examined at both room temperature and typical reservoir temperatures. The most favourable candidate nanoparticle composition subsequently underwent stability experiments in order to produce long term stable dispersed nanoparticle suspensions. The magnetic nano-fluid was then used in experiments to track the waterflooding of a heavy oil saturated sandpack in real time using magnetic susceptibility scanning. Attempts to track the process were also undertaken with CT scanning for comparison. The successful waterflood 2 experiment revealed the formation, growth and movement of a significant positive magnetic susceptibility peak. This peak formed at the injection end of the flow cell and migrated towards the production end as the waterflooding progressed. The peak was likely due to the higher concentration of nanoparticles collecting at the main water-heavy oil interface(s). This result was significant as it provided a means to quantitatively track the progression of the waterflood in real time. The increased accumulation of nanoparticles at the water-heavy oil interface(s) was further supported by the material collected in the production jars. While the CT attenuation profiles showed some correspondence with the magnetic results, they were not able to track the progression of the waterflood, most likely due to the low CT contrast between the nano-fluid and the heavy oil. Once the main water-heavy oil interface(s) had passed through the sandpack the magnetic profiles had a constant shape similar to the porosity profile (as determined by the CT derived porosity variation). The results suggested that the magnetic technique has potential for monitoring larger scale commercial waterflooding operations. The potential retention of magnetic nanoparticles after water-flushing was also examined. These results were then compared to a case study where naturally occurring hematite nanoparticles in a tight gas reservoir were shown to have a detrimental effect on the reservoir quality by reducing the permeability. The comparison showed that the concentrations of retained nanoparticles in a series of laboratory water flushing experiments were significantly less than the concentrations causing the detrimental effects in the tight gas reservoir case study. A further study was conducted on the magnetic properties of hematite nanoparticles. Although hematite nanoparticles were initially considered as possible magnetic contrast agent tracers for reservoir characterization, one sample exhibited an unexpected diamagnetic magnetic susceptibility signal during initial room temperature measurements. A search of the literature also revealed another apparent “diamagnetic” result in another sample of hematite nanoparticles. These results were unusual as hematite is expected to have canted antiferromagnetic behaviour at room temperature. This led to an investigation of whether the hematite nanoparticles were behaving diamagnetically themselves or if the observed magnetic signal was due to the diamagnetic matrix overwhelming a weak canted antiferromagnetic signal from the hematite nanoparticles. After comprehensively investigating three different sizes of hematite nanoparticles it was concluded that the nanoparticles were not diamagnetic but that the “diamagnetic” magnetic susceptibility signal resulted from the diamagnetic matrix (in which the nanoparticles were dilutely dispersed) overwhelming the weak hematite signal.

Transforming the aging electric grid to a smart grid is an active area of research in industry and the government. One of the main objectives of the smart grid is to improve the efficiency of power generation, transmission and distribution and also to improve the stability and the reliability of the grid. In order to achieve this, various processes involved in power generation, transmission, and distribution should be armed with advanced sensor technologies, computing, communication and networking capabilities to an unprecedented level. These high speed data transfer and computational abilities aid power system engineers to obtain wide area measurements, achieve better control of power system operations and improve the reliability of power supply and the efficiency of different power grid operations. In the process of making the grid smarter, problems existing in traditional grid applications can be identified and solutions have to be developed to fix the identified issues. In this dissertation, two problems that aid power system engineers to meet the above mentioned smart grid's objective are researched. One problem is related to the distribution-side smart grid and the other one is a part of the transmission-side smart grid. Advanced Metering Infrastructure (AMI) is one of the important distribution-side smart grid applications. AMI is a technology where smart meters are installed at customer site which gives the utilities the ability to monitor and collect information related to the amount of electricity, water, and gas consumed by the user. Many recent research studies suggested the use of 3G cellular CDMA2000 for AMI network as it provides an advanced and cost effective solution for smart grid communications. Taking into account both technical and non-technical factors such as extended lifetime, security, availability and control of the solution, Alliander, an electric utility in Netherlands deployed a private 3G CDMA2000 network for smart metering. Although 3G CDMA2000 satisfies the requirements of smart grid applications, an analysis on the use of the current state of the art 3G CDMA2000 for smart grid applications indicates that its usage results in high percentage of control overhead, high latency and high power consumption for data transfer. As a part of this dissertation, we proposed FLEX-MAC - a new Medium Access Control (MAC) protocol that reduces the latency and overhead in smart meter data collection when compared to 3G CDMA2000 MAC. As mentioned above the second problem studied in this dissertation is related to the transmission-side grid. Power grid transmission and sub-transmission lines are generally protected by distance relays. After a thorough analysis of U.S. historical blackouts, North American Electric Reliability Council (NERC) has concluded that the hidden failure induced tripping of distance relays is responsible for 70% of the U.S. blackouts. As a part of this dissertation, agent based distance relaying protection scheme is proposed to improve the robustness of distance relays to hidden failures and thus reduce the probability of blackouts. This dissertation has two major contributions. First, a hierarchically distributed non-intrusive Agent Aided Distance Relaying Protection Scheme (AADRPS) is proposed to improve the robustness of distance relays to hidden failures. The problem of adapting the proposed AADRPS to a larger power system network consisting of thousands of buses is modeled as an integer linear programming multiple facility location optimization problem. Distance relaying protection scheme is a real time system and has stringent timing requirements. Therefore, in order to verify if the proposed AADRPS meets the timing requirements or not and also to check for deadlocks, verification models based on UPPAAL real time model checker are provided in this dissertation. So, the entire framework consisting of AADRPS that aids in increasing the robustness of distance relays and reducing the possibility of blackouts, the multiple facility location optimization models and the UPPAAL real time model checker verification models form one of the major contributions of this dissertation. The second contribution is related to the MAC layer of AMI networks. In this dissertation, FLEX-MAC - a novel and flexible MAC protocol is proposed to reduce the overhead and latency in smart meter data collection. The novelty of the FLEX-MAC lies in its ability to change the mode of operation based on the type of the data being collected in a smart meter network. FLEX-MAC employs Frame and Channel Reserved (FCR) MAC or Frame Reserved and Random Channel (FRRC) MAC for scheduled data collection. Power outage data in an AMI network is considered as a random data . In a densely populated area, during an outage, a large number of smart meters attempt to report the outage, which significantly increases the Random Access CHannel (RACH) load. In order to reduce the RACH traffic during an outage, this dissertation proposes a Time Hierarchical Scheme (THS). Also, in order to minimize the total time to collect the power outage data, a Backward Recursive Dynamic Programming (BRDP) approach is proposed to adapt the transmission rate of smart meters reporting an outage. Both the Optimal Transmission Rate Adaption and Time Hierarchical Scheme form the basis of OTRA-THS MAC which is employed by FLEX-MAC for random data collection. Additionally, in this work, Markov chain models are presented for evaluating the performance of FCR and FRRC MACs in terms of average throughput and delay. Also, another Markov model is presented to find the mean time to absorption or mean time to collect power outage data of OTRA-TH MAC during an outage.

Memory is dependent on a variety of factors from individual differences in storage capacity to cultural differences in attentional biases. While previous research has studied the effect of the intentionality of actions on memory, few have looked into how the intersection of intentionality and morality might affect memory. This study sought to examine how morality and intentionality affect participants’ ability to remember specific information about an event. Participants read six stories from a single condition in a 2 (moral/neutral) x 2 (intentional/accidental) between-subjects design. After half an hour of non-verbal distractor tasks, participants were asked to freely recall as much information as they could from the previous stories. Although we found few significant results, we did find consistent trends suggesting that moral intentional scenarios improve participants’ recall of overall memory about the event. Specifically, morality and intentionality show trends toward improving participants’ memory for information about the story’s agent, their action, and whether or not their action was done intentionally or accidentally. The lack of significance could stem from a small sample size for each condition (N=20), which did not give enough power for statistical analyses. We discuss this and other limitations, as well as future directions on how these preliminary results apply to cultural and linguistic differences in memory and how this could have important implications for eyewitness testimony.

This dissertation presents the design, development and short-term evaluation of an embodied conversational agent designed to mentor human users. An embodied conversational agent (ECA) was created and programmed to mentor African American computer science majors on their decision to pursue graduate study in computing. Before constructing the ECA, previous research in the fields of embodied conversational agents, relational agents, mentorship, telementorship and successful mentoring programs and practices for African American graduate students were reviewed. A survey used to find areas of interest of the sample population. Experts were then interviewed to collect information on those areas of interest and a dialogue for the ECA was constructed based on the interview's transcripts. A between-group, mixed method experiment was conducted with 37 African American male undergraduate computer science majors where one group used the ECA mentor while the other group pursued mentoring advice from a human mentor. Results showed no significant difference between the ECA and human mentor when dealing with career mentoring functions. However, the human mentor was significantly better than the ECA mentor when addressing psychosocial mentoring functions.

In an organizational context, policies are a collection of high-level, operation and management goals and/or rules which are used to define the expected behaviours and processes of organizational actors. Hence policies are concerned with ordinary, non-exceptional business processes and how organizational actors perform these processes. However, in every organization, unexpected events do occur from time to time which require deviation from established policies, and currently there is very little known in the literature on how the actors can proceed under such situations. This thesis aims to propose a method which includes a multi-step framework to design and develop applications that can assist organizational actors in deviating from policies while facing unexpected or exceptional situations by allowing collaborative policy-based information systems to identify policy deviations by its users, present them with alternate actions and behaviors to attain the required outcomes and, when necessary, allow them to deviate from the policy and perform a non-conforming action. This study has been conducted by following Hevner’s framework for design science research which suggests obtaining awareness of the problem from the environment, putting forward suggestions to solve the problem, contributing to the pool of study through publications and evaluating the solution to validate the generalizability and correctness of the solution. The outcomes from this research are, a policy deviation framework based on existing literature and a multi-step policy deviation method which can assist organizational actors in detecting and deviating from policies when necessary. The methods proposed in this study have been evaluated using hypothetical scenarios based on real policies and through randomly generated simulations, and has been shown to be both applicable and effective. In terms of contributions to research, the fields of CSCW, software agents, decision making, as well as policy based planning and management can benefit significantly from this work.

Three out of five U.S. adults search the Internet for health information, and about one out of ten seek others who have similar health issues. Users can gather information and connect with others through virtual environments. This research tested the effect of the expectancy violations theory through immediacy and communicator reward value on evaluations of a virtual counselor during a health intervention. Participants (N = 91) interacted with a high or low reward communicator in Second Life who engaged in positive or negative immediacy behaviors. The participant’s perception of positive immediacy in the high reward virtual counselor increased evaluations of trust. For the low reward communicator, perceptions of positive immediacy increased evaluations caring and goodwill. These findings are partially consistent with expectancy violations theory. Belief in the virtual representation’s agency increased positive evaluations of the virtual counselor. Implications, limitations, and future directions are discussed.

This dissertation focuses on robust coalition formation between selfish agents in a dynamic environment where contracts are unenforceable. Previous research on this topic has covered each different aspect of this problem, but no research successfully addresses these factors in combination. Therefore, a novel approach is required. This dissertation accordingly has three major goals: to develop a theoretical framework that describes how selfish agents should select jobs and partners in a dynamic, contractless environment, to test a strategy based on that framework against existing heuristics in a simulated environment, and to create a learning agent capable of optimally adjusting its coalition formation strategy based on the level of dynamic change found in its environment. Experimental results demonstrate that the Expected Utility (EU) strategy based on the developed theoretical framework performs better than strategies using heuristics to select jobs and partners, and strategies which simulate a centralized “manager”. Future work in this area includes altering the EU strategy from an anytime strategy to a hill-climbing one, as well as further game theoretic explorations of the interactions between different strategies.

Current service-oriented architectures lack business-level software abstractions. As a result, service implementations are unnecessarily rigid. Commitment-Based SOA or CSOA, an agent-oriented approach to SOA, fills this gap. The key insight of CSOA is that commitments are crucial to realizing the full possibilities of engagement. In CSOA, each business service is modeled as an agent. CSOA gives primacy to the interactions among agents. Interactions have business meaning in terms of the commitments the agents have toward each other. This dissertation takes a distributed systems view of CSOA, where agents communicate using asynchronous messaging. A problem that arises in distributed settings is that of commitment misalignment: an agent comes to infer a commitment from another agent, but the other agent does not infer that commitment. A commitment misalignment precludes any possibility of successful engagement among agents. We formalize alignment under asynchronous messaging. We consider three causes of misalignments. (1) Autonomy: agents are free to send messages; in other words, they communicate asynchronously. (2) Distribution: in a distributed system, some agents would in general have more information than others. (3) Interface incompatibility: agents assign different meanings to messages. To address the first two causes, we propose a formalization of commitments that consists of three elements: a semantics of the commitment operations; messaging patterns that implement the commitment operations; and weak constraints on agents' behaviors to ensure the propagation of vital information. The constraints constitute additional messaging patterns that are critical to alignment. We prove that our formalization ensures that no misalignment arises because of autonomy and distribution. We illustrate the generality of our formalization with several real-life scenarios. To address interface incompatibility, we formulate a decision procedure that checks for interface compatibility, and prove its correctness.

At Ctest Laboratories we are exploring the notion of automated conversion of the semi-structured text to an epistemic structure suitable for deductive inference. In this paper we will develop an epistemic structured representation for electronic transcripts ofinterrogative domains. We propose that knowledge which is typically not visible to keyword search or string matching, can be readily extracted from the an electronic transcript when it is given an appropriate epistemic structure. We introduce an Epistemic Structure Es and a process for converting a semi-structured transcript from and interrogative domain to Es. In this paper we restrict our discussion and analysis to transcripts that have been stored as semi-structured text. In particular we are interested in any knowledge that can be deduced by an interrogative agent from the content of an electronic transcript. Further we develop the notion of an interrogative agent that relies on epistemic justification as a condition for knowledge.

In this paper, we explore the concept of epistemic visualization in interrogative domains. Epistemic visualization is the process and result of developing visual models that capture the structure, content, justification and acquisition of knowledge obtained by a software agent in a knowledge-based system. The knowledge is the foundation in which the agent can respond to queries against a corpus containing questions and answers. The visualizations are therefore used to examine the quality of the software agent's knowledge. The visual models will include justification and commitment artifacts as well as knowledge acquisition flow. The visualization will demarcate the a priori and posteriori knowledge. The knowledge of the software agent is stored in epistemic structures which are knowledge representation schemes that supports the basic concepts of knowledge as defined by the tripartite analysis of knowledge. Epistemic visualization is used to analyze the quality of the knowledge of a software agent in an interrogative domain. For our purpose, interrogative domains are hearings, trials, interrogations, personality test or any document source in which the primary content is questions and answers pairs. In this paper, we introduce the Epistemic Structure Es that captures the agent's knowledge and the visualization of that epistemic structure using common visualization techniques.

Current syndromic surveillance systems utilize centralized databases that are neither scalable in storage space nor in computing power. Such systems are limited in the amount of syndromic data that may be collected and analyzed for the early detection of infectious disease outbreaks. However, with the increased prevalence of international travel, public health monitoring must extend beyond the borders of municipalities or states which will require the ability to store vasts amount of data and significant computing power for analyzing the data. Intelligent mobile agents may be used to create a distributed surveillance system that will utilize the hard drives and computer processing unit (CPU) power of the hosts on the agent network where the syndromic information is located. This thesis proposes the design of a mobile agent-based syndromic surveillance system and an agent decision model for outbreak detection. Simulation results indicate that mobile agents are capable of detecting an outbreak that occurs at all hosts the agent is monitoring. Further study of agent decision models is required to account for localized epidemics and variable agent movement rates.

In Chapter I. Introduction, two important physiological phenomena in breast cancer, apoptosis and angiogenesis, are described. Two molecular biomarkers, caspases for apoptosis and matrix metalloproteinase’s for angiogenesis, are described particularly in the context of molecular imaging detection methods. In Chapter II. Responsive MR contrast agents, the responsive contrast agents in MR imaging are reviewed based on the response mechanisms, such as tumbling time, water accessibility and water exchange rates. Detecting enzyme activity has wide applications and is a hot issue in molecular imaging research. In Chapter III. Solution phase synthesis of peptidyl contrast agents, a new facile synthetic methodology for creating peptidyl DOTA using an aminoDOTA core compound is described. The solution phase synthesis methodology has limitations for the introduction of diverse sequences of peptides on a DOTA moiety. To overcome this limitation, in Chapter IV. Solid phase synthesis of peptidyl contrast agents, a solid phase synthetic approach was investigated. The solid phase synthetic method has been applied for the synthesis of diverse peptidyl DOTA structures for research presented in this dissertation, and for other molecular imaging research. In Chapter V. Detection of enzyme activity based on PARACESET effect, the newly synthesized caspase-3 targeting peptidyl MR contrast agent was evaluated for the physico/chemical properties. The in vitro enzyme activity detection was demonstrated using caspase-3 and the newly synthesized peptidyl DOTA MR contrast agent. Kinetics studies were conducted by measuring PARACEST effects and the PARACEST kinetics results were compared with the results from fluorescence enzyme kinetics studies. In Chapter VI. Review of DCE-MRI contrast agents, the contrast agents used for DCE-MRI were reviewed according to the criteria of molecular weight. The conventional DCE-MRI method was implemented and tested to show the utility of this technique to study tumor angiogenesis. PARACEST DCE-MRI is new concept of DCE-MRI in many aspects. The PARACEST DCE-MRI technique was studied and the results were compared with conventional T1 DCE-MRI. The results were summarized in Chapter VII. PARACEST DCE-MRI. In Chapter VIII. Future Research, the research directions in the future and tentative projects are suggested.

The classic board game of checkers is ideally suited for research in AI game-playing programs or agents. The objective behind Soar Checkers is to investigate if it is possible to create an agent-based game playing system that would beat novices with ease and at least challenge advanced novice to intermediate-level players by designing a rules-based expert system whose knowledge base consists of nothing more than the rules of checkers, and a set of guidelines for game-play based on good strategy. Soar was chosen as the platform for building this agent because it came built-in with features that facilitate creating rules-based expert systems, has been proven to be fairly reliable in developing such systems (including flight simulators) for over twenty years and makes it relatively straight-forward to have multiple agents play each other, and to add or modify features or strategies to the agents. Though the problem definition makes it inherently hard to objectively quantify the results, the objectives were successfully achieved for the most part. It was also seen that all other things being equal, the player going second ( White ) has a built-in advantage, thereby confirming a widely held belief among the checkers community.

Lipid-lowering agents (LLAs) such as statins have been shown to have beneficial effects on cardiovascular events in patients with cardiovascular risk factors. The evidence that statins positively affect the incidence of conditions with outcomes sharing a common pathway with cardiovascular disease, such as dementia and type 2 diabetes, is inconsistent in data collected in clinical intervention and observational studies. This dissertation investigates the effects of lipid-lowering agents, the majority of which are statins, on incidence of dementia, on incidence of dementia in diabetics compared to nondiabetics, and on incidence of type 2 diabetes. The study was based on data from a prospective cohort study (Sacramento Area Latino Study of Aging [SALSA]) in a population comprised of 1789 older (>60 years of age) community-dwelling Mexican Americans. A multistage process was used for the evaluation of dementia and cognitive impairment not demented (CIND). Participants who fell below predetermined scoring results were evaluated clinically by an adjudication team. Dementia was diagnosed using DMS-IV criteria. In the analyses, dementia and CIND were combined into one variable: dementia/CIND. Type 2 diabetes status was determined by (1) fasting plasma glucose level ≥126 mg/dL; or (2) use of an antidiabetic medication; or (3) self-report of a doctor's diagnosis of type 2 diabetes. LLA-use was ascertained at each participant's home annually by direct inspection. Cox Proportional Hazards models were used to assess the association between LLA-use and incidence of dementia/CIND and on incidence of type 2 diabetes. LLA-use was modeled as a time-dependent variable. Results from this cohort study showed that lipid-lowering agents appeared to decrease the risk of dementia/CIND over a 5-year followup period in a population of Mexican Americans. Nondiabetics who used LLAs or statins had the lowest incidence of dementia/CIND compared to all other combinations of diabetes status and LLA-use. Diabetics who did not use LLAs had the highest incidence of dementia/CIND compared to all other combinations of diabetes status and LLA-use. In the evaluation of the association between LLA-use and incidence of type 2 diabetes, LLAs did not impact the incidence of type 2 diabetes over the 5-year followup period in this population of Mexican Americans.

In the development of anti-cancer drugs, it is important to maintain selective toxicity towards tumor tissues. Presented herein is a novel polyrotaxane (PR)-based delivery system that possesses the potential to achieve a highly effective yet less toxic cancer therapy. Briefly, the approach involves synthesis of the PR-anti-cancer drug (i.e. camptothecin or daunorubicin) conjugates by threading alpha-cyclodextrin (alpha-CD) monomers onto a poly(ethylene glycol) (PEG) chain, blocking both ends of the PEG thread with bulky tyrosine residues, and then coupling the anti-cancer drugs to the activated functional groups on alpha-CD via hydrolyzable ester linkages. To design a system for enhancement of therapeutic efficacy of anti-cancer drugs and reduction in their toxic effect towards tissues surrounding the tumor, a cell-penetrating peptide (i.e. low molecular weight protamine (LMWP)) is linked to the PR-drug conjugate to allow for a tumor-specific, intracellular delivery of anti-cancer drugs. In order to avoid non-selective uptake of the conjugates by normal tissues following their administration, the transmembrane function of LMWP on the conjugates is masked by binding with heparin. This system was designed in such a manner that after accumulation of the conjugates at the tumor site by passive targeting, protamine sulfate, a clinical heparin antagonist that binds heparin stronger than LMWP, is administered subsequently to unmask heparin inhibition on LMWP, permitting an effective intracellular uptake of the LMWP-PR-drug conjugates. Once inside tumor cells, anti-cancer drug molecules are released from the PR polymer chain by hydrolysis, yielding a sustained level of the drug within tumor cells. In this thesis, in vitro cell culture results were presented to demonstrate the feasibility of this drug delivery system. The LMWP-PR-drug conjugates, which yielded a linear and sustained release of anti-cancer drug over a period of greater than 4 days, were synthesized and characterized. Intracellular uptake of these LMWP-PR-drug conjugates by A2780 cells and regulation of such uptake by heparin and protamine were tested by the MTT assay and confocal/flow cytometry methods, respectively. These results suggest that this system offers the potential generic system for delivery of small anti-tumor agents possessing poor solubility or reaction selectivity.

Humans carry mental models concerning the behaviors, looks, and operation of products, tools, and items used in their daily lives. When these items do not fit a user's conceptual model confusion and inefficiency occur. There are four basic types of mental models based on interactive activities: 1) instructing, 2) conversing, 3) manipulating and navigating, and 4) exploring and browsing. This thesis will focus on the conversing conceptual model and its application to communications between human-agent teams to best fit a user's mental model for that communication. A non-anthropomorphic framework does not exist for use in military applications such as; target detection, nuclear, biological, and chemical agent detection, and explosive ordinance disposal. As agents become increasingly autonomous and complex in the currently military working environment an effective and un-confusing non-anthropomorphic meta-language framework must be explored and developed to fulfill the need for human-agent communications. The meta-language framework may consist of visual and audio cues as pose, motion, color, and non-speech sounds. This thesis will attempt to identify and evaluate a non-anthropomorphic framework of communications between human-human, human-agents, and agent-agent teams that will maximize the effectiveness of the communications in terms of efficiency and interpretation.

This dissertation considers three topics regarding agents' incentives and behavioral characteristics. Chapter 1 investigates agents' overconfidence in forecasting by analyzing their learning behavior both theoretically and empirically. In models with repeated forecasts, agents' learning patterns reveal information regarding their overconfidence and abilities. Based on theoretical predictions, I develop empirical methods to test whether previous forecasting accuracy leads agents to become overconfident. Using detailed data on financial analysts' forecasts, I find that (i) analysts' past accuracy does not necessarily lead them to be overconfident; (ii) analysts with larger past deviations from the consensus forecasts do not exhibit more overconfidence; and (iii) overall, analysts do not exhibit overconfidence. Therefore, contrary to the results from previous studies, in practice, overconfidence does not significantly affect the decisions of financial analysts. Chapter 2 examines the relationship between an agent's decision to increase productivity and the decision to overstate performance. When the market rationally expects the agent's overstatement, we show that: (i) the relative size of overstatement decreases in true performance; (ii) higher cost of falsification increases the agent's incentive for production effort even when the costs of two efforts are independent; and (iii) the principal cannot achieve the first-best outcome even when the agent is risk-neutral and the market expectation is correct. Chapter 3 explores the relation between CEO pay-performance ratios and the stock return sensitivities in response to firms' earnings announcements. I test theoretical predictions using Dow Jones Industrial data over the period from 1994 to 2001. Through examining a new measure, stock return sensitivities, in response to firm's earning announcements, I find that stock returns are more sensitive to the higher CEO pay-performance ratio regardless of earnings categories. This implies that CEOs whose pay-performance ratios are high are more (less) likely to be involved in falsification when the firm's performance is bad (good). This supports theoretical predictions derived from the study of comparative statics. Moreover, CEOs who have been in the position for a shorter tenure have a higher (lower) incentive to manipulate earnings when their firms' performance is bad (good).

A business process streamlines how different business parties interact with one another, in order to achieve a business goal. The modeling and enactment of business process is notoriously complex, especially in open systems where the participants are autonomous and heterogeneous. Conceptually, a business process consists of two important elements; the business protocols that specify the interactions between the partners and the business policies that drive the partners? behavior during the enactment of protocols. Business policies are an integral and important component of business processes. Business policies are often expressed and implemented as business rules. It is common to embed these business rules within the business process implementation. When the business practices or policies change, as they often do, it is difficult to dynamically manage these changes without affecting the business process implementation. It is a challenge to correctly reflect the policy changes with minimal or no change to the implementation of the business process. The conventional workflow approaches of representing business policies, reduce the flexibility and reusability of business processes. It is possible to control the behavior of protocol participants dynamically, without changing the protocol specification by representing the private internal business policies separate from the generic, public business protocols. However, given a separate policy and protocol specification, it is important that when the participants enact the protocol, the behavior dictated by their local policies be congruent with the protocol specifications. The focus of this thesis is to develop a methodology to configure the private policies of the participant such that, its behavior during protocol enactment is always compliant with the protocol. We propose a methodology that describes how the agent policies should be added to the protocol specification such that the protocol is not violated during enactment.

Microelectrodes for stimulating and/or recording signals have made possible direct electrical connections with living neural tissue. Silicon electrode arrays are excellent tools for communication with living neurons however they have limited chronic recording abilities. The inability to maintain long-term electrode-neuron communication is attributed to an increase in impedance of implanted electrodes and neuronal loss around the implant that is associated with an inflammatory reaction within CNS. To improve the long-term integration and performance of these implanted devices, efforts have been dedicated to understanding the factors influencing the functionality of the inserted electrodes and to the development of novel coating technologies that can be used to modify the electrode surface. Our approach takes advantage of recent developments in the synthesis, processing, and characterization of novel polymeric materials and the use of relevant biologic elements and in vitro cell models. In this thesis, we present studies concentrated on modification of both the metal microelectrode sites of neural electrodes using conducting polymers and the shanks of neural electrodes using alginate hydrogels. This entails the use of polymers for: (1) creation of soft, electrically conductive, bioactive coatings (5-500 mum) that can be deposited onto the electrode shaft providing a biocompatible, mechanical buffer at the interface between the neurons and the electrodes, (2) modification of the neural electrode sites by high surface area morphology conducting polymers grown through the hydrogel layers to reduce impedance as low as 7 kO and improve communication with neurons, (3) incorporation of neurotrophic proteins into conducting polymers to encourage growth of neurities from neurons near the electrodes, (4) the development of nanoparticle-release vehicles to deliver anti-inflammatory drugs to attenuate the host inflammatory response at the site of implantation. The effects of these biomaterials on signal transduction and cell/electrode interaction in vitro and in vivo were also studied. In summary, we present a novel polymer-based coating technology for neural electrodes. Our in vitro and in vivo data suggest these bioactive, electrically conductive coatings can be used to overcome the current limitations of chronically implanted neural electrodes and represent a useful means for local administration of therapeutic agents for neural electrodes.

The formation of nitrogen-containing molecules is of great importance in synthetic organic chemistry owing to the abundance of alkaloids that exhibit biological activity. While the first two projects deal with expanding the synthetic tools available for synthesis of such compounds, the final project focuses on using existing methodology to create and test novel potential clinical agents. The use of (2-azaallyl)nitriles in double allylation reactions with allylmagnesium bromide to generate N, N-bis(3-butenyl)amines is described. The (2-azaallyl)nitriles function as synthetic equivalents of amine alpha,alpha'-dications, also called 2-azaallyl dications. This chemistry allows for the expeditious construction of highly substituted amines, resulting in the formation of two new carbon-carbon bonds adjacent to the nitrogen atom. The doubly allylated products are converted to 2,3,6,7-tetrahydroazepines by ring-closing metathesis. Many biologically-active natural products contain the azepine ring, so facile methods for its formation provide valuable synthetic tools. Also discussed is the formation of pyrrolizidines from N-(tri- n-butylstannyl)methylphthalimides. Through nucleophilic addition of an organometallic reagent, the phthalimides could be converted to cyclic carbinol amides, which were shown to undergo ionization and destannylation under acidic conditions to generate azomethine ylides. Inclusion of a suitable dipolarophile resulted in capture of the azomethine ylide to provide the pyrrolizidine. Various substituents on the phthalimide were tolerated by this methodology, and stabilized succinimide derivatives also underwent successful cycloadditions. Given the large number of biologically-active natural products that possess the pyrrolizidine ring structure, this chemistry could find wide synthetic application. Finally, the preparation of 2-(2,5-dihydropyrrol-1-yl)-1,4-quinones by the coupling of quinones with pyrrolines is discussed. The 2-(2,5-dihydropyrrol-1-y1)-1,4-quinones were designed to be masked alkylating agents, revealed upon exposure to light. The pyrroline of the 2-(2,5-dihydropyrrol-1-yl)-1,4-quinones is relatively unreactive toward nucleophiles, but upon photolysis, an internal oxidation/reduction reaction occurs, transforming the quinone into a hydroquinone and the pyrroline into a pyrrole. The newly-formed pyrrole is highly electrophilic and readily undergoes an alkylation reaction. Eventually, the presence of oxygen may reoxidize the hydroquinone to a quinone. The design of such photoactivatable alkylating agents is a worthwhile endeavor because it provides a handle for control of the alkyation, thereby making it more attractive as a potential clinical agent.

Coalitions are collections of agents that join together to solve a common problem that either cannot be solved individually or can be solved more efficiently as a group. Each individual agent has capabilities that can benefit the group when working together as a coalition. Typically, individual capabilities are joined together in an additive way when forming a coalition. This work will introduce a new operator that is used when combining capabilities, and suggest that the behavior of the operator is contextual, depending on the nature of the capability itself. This work considers six different capabilities of Unmanned Air Vehicles (UAV) and determines the nature of the new operator in the context of each capability as coalitions (squadrons) of UAVs are formed. Coalitions are formed using three different search algorithms, both with and without heuristics: Depth-First, Depth-First Iterative Deepening, and Genetic Algorithm (GA). The effectiveness of each algorithm is evaluated. Multi agent-based UAV simulation software was developed and used to test the ideas presented. In addition to coalition formation, the software aims to address additional multi-agent issues such as agent identity, mutability, and communication as applied to UAV systems, in a realistic simulated environment. Social potential fields provide a means of modeling a clustering attractive force at the same time as a collision-avoiding repulsive force, and are used by the simulation to maintain aircraft position relative to other UAVs.

Despite its negative ethical connotations, deception is a useful tool for human social interaction, and plays an important role in the process of creating the stories that pervade our popular culture. In this paper, we describe the deception planner, an implementation of a model of strategic deception. Strategic deception is deception performed in order to achieve or enable some higher goal, as opposed to deception that is performed for the sake of deceiving, or for an unstated purpose. Given a model of a deceiver holding ulterior goals, a model of the goals and abilities of a target agent to be deceived, and a model of the relevant pieces of the world, the deception planner generates a set of statements about the current world state which may be either true or false. Those statements are communicated to the target agent, which updates its world state to reflect this new information. The target then performs planning to achieve its own goals, with no knowledge of the deceiver's goals. If the deception planner generates an successful set of statements, the target agent will create a plan that achieves the deceiver's ulterior goals despite no knowledge of those goals. To find the set of statements that will generate this desired behavior from the target agent, the deception planner models the target agent's planning process. The deception planner searches for a plan that achieves the target agent's goals as well as the deceiver's ulterior goals. When such a plan is found, it is labeled the candidate plan, and the deceiver gives the target agent enough (dis)information so that, given the target agent's knowledge of the world, she can generate that plan. The candidate plan may depend on lies, chosen by the deception planner. The planner ensures that any lies told are not discovered before the target executes enough of the plan to achieve the ulterior goals. Once a candidate plan has been found, the deception planner the finds and counters competing plans. Competing plans are plan that achieve the target's goals but not the deceiver's goals, but are of equivalent or better quality than the candidate plan according to some metric shared by the target and deceiving agent. Because they are of the same or better quality, the target agent may choose a competing plan instead of the candidate plan. A competing plan is countered by undermining through lying a belief that is necessary for that plan to be executable. Although the deception planner fits within a body of work on agent deception, the goal of this algorithm is unique in its focus on causing a target agent to act in order to achieve a deceiver's goals, and in its utilization of a model of the goals and planning abilities of the target agent to that end.

Implementing an e-market for limited supply perishable asset (LiSPA) products is a problem at the intersection of online purchasing and distributed decision support systems (DistDSS). In this dissertation, we introduce and define LiSPA products, provide real-world examples, develop a framework for a distributed system to implement an e-market for LiSPA products, and provide proof-of-concept for the two major components of the framework. The DistDSS framework requires customers to instantiate agents that learn their preferences and evaluate products on their behalf. Accurately eliciting and modeling customer preferences in a quick and easy manner is a major hurdle for implementing this agent-based system. A methodology is developed for this problem using conjoint analysis and neural networks. The framework also contains a model component that is addressed in this work. The model component is presented as a mediator of customer negotiation that uses the agent-based preference models mentioned above and employs a linear programming model to maximize overall satisfaction of the total market.

Nitric oxide (NO) has been shown to have significant anti-platelet activity. Polymers capable of releasing NO may also show enhanced blood compatibility. To this end, N,N'-dialkylhexamethylenediamine diazeniumdiolates (zwitterionic) and their bis dizeniumdiolate analogues were synthesized and characterized. It was determined that the side chain length had little affect on the apparent half-lives of the zwitterionic diazeniumdiolates. The bis-diazeniumdiolates were found to have shorter apparent half-lives than their zwitterionic analogues. Both the zwiterionic and bis-diazeniumdiolates were incorporated into hydrophobic polymer matrixes and their NO-release profiles determined using chemiluminescence. For polymer matrixes prepared with the more lipophilic diazeniumdiolate species, NO-release was enhanced by the addition of a lipophilic borate salt. It was determined that the borate salt serves to buffer the polymer film during the NO-release process. NO-releasing polymers were prepared using this approach that exhibited NO surfaces fluxes of at least 4 x 10-10 mol·cm-2·min -1. The more lipophilic zwitterionic diazeniumdiolate, N,N'-dibutylhexamethylenediamine diazeniumdiolate, was embedded into polymer coatings and used to prepared coatings fro vascular access grafts and electrochemical oxygen sensors. When these NO-releasing polymers were used as coatings for medical devices, significant reduction of thrombus formation on their surfaces was observed compared to control surfaces (without NO release). Secondly, synthetic methods were explored to covalently attach diazeniumdiolates to polyurethane backbones. The first method involved preparing polyurethanes that contained diamine chain extenders. These diamine-containing polyurethanes were then reacted with NO. The resulting polymers were found to release mostly nitrite. However, when these diamine-containing polyurethanes are reacted with NO in the presence of exogenous salts, an increase in the amount of NO compared to nitrite was achieved. The second method involved incorporation of protected pre-formed diazeniumdiolate moieties directly onto chain extender diols incorporated into the polyurethane backbone. More control over the NO-loading was demonstrated using this approach.

A user interface softbot is a software agent that controls an interactive system through its graphical user interface, relying on visual information of the system rather than an application programming interfaces or access to source code. We have developed a prototype system that facilitates the use and extension of interface softbots, reforming the programming process and making it easier for new developers. We present the JSegMan substrate that facilitates the representation and identification of the conventional graphical user interface. The JSegMan substrate consists of sensors, effectors and framework for an agent that can control the user interface environment. Using image processing the sensor builds a representation of the desktop's visual interface. The effector module generates mouse and keyboard gestures to control the desktop environment. The sensor and effector modules work as eyes and hands of a controller application that can be tailored for a given application domain. We also present three applications - MSN Chatbots, the classical Blocks World problem solver and a GUI testing tool that use the JSegMan substrate and demonstrates applicability of JSegMan in use with off-the shelf applications, PDDL based planners and in testing environment respectively.

Protocols in open and dynamic multiagent systems cannot be modeled via formalisms such as finite state machines (FSMs). FSMs though formal, lack content, that is, a protocol-level semantics, which leads to rigidity in protocols. We propose formalism called Nonmonotonic Commitment Machines (NCMs) for representing protocols. An NCM gives a commitment-based semantics to actions and states in a protocol. Protocols represented as NCMs afford the agent flexibility in interactions with other agents. In particular, situations in protocols when nonmonotonic reasoning is required can be efficiently represented in NCMs. For applications that need efficient execution, we show how to compile an NCM into an FSM and prove the compilation to be sound and complete.

For many applications, the success of multiagent systems depends on cooperation among the participating agents. Autonomous entities often face the economic and social dilemma of whether to act in trustworthy manner. Reputation mechanisms and institutional norms are currently used to make an individual agent responsible for its actions. It is challenging to achieve trust in an anonymous setting. We consider the problem of trust with respect to fairness, especially in an anonymous setting. Decision mechanisms should be built into agents to yield trustworthy behavior. We study conditions under which such cooperation can evolve. Our simulations show that small group interactions make it favorable for fairness to emerge. Techniques such as tagging can generate behavior analogous to small groups.

Many of the contemporary routing algorithms use simple mechanisms such as flooding or broadcasting to disseminate the routing information available to them. Such routing algorithms cause significant network resource overhead due to the large number of messages generated at each host/router throughout the route update process. Many of these messages are wasteful since they do not contribute to the route discovery process. Reducing the resource overhead may allow for several algorithms to be deployed in a wide range of networks (wireless and ad-hoc) which require a simple routing protocol due to limited availability of resources (memory and bandwidth). Motivated by the need to reduce the resource overhead associated with routing algorithms a new implementation of distance vector routing algorithm using an agent-based paradigm known as Agent-based Distance Vector Routing (ADVR) has been proposed. In ADVR, the ability of route discovery and message passing shifts from the nodes to individual agents that traverse the network, co-ordinate with each other and successively update the routing tables of the nodes they visit.

Planar 15-metallacrown-5 complexes that encapsulate lanthanides were made using simple alpha-amino acid hydroxamate ligands and CuII. The use of phenylalanine hydroxamic acid (pheHA) results in a chiral, face differentiated, amphiphilic molecule in which benzyl groups are oriented towards one face (GdCu5pheHA53+). A series of crystal structures shows that as the lanthanide radius increases, (Tm III, HoIII, TbIII, GdIII, EuIII, SmIII, NdIII, and La III were encapsulated) the cavity provided by five donor oxygen atoms expands, from 1.058A (TmIII) to 1.150A (La III). The metallacrown becomes less ruffled in order to facilitate this expansion. The average distance of the five CuII ions from the mean plane that they form can be measured to quantify the ruffling. The average distance varied from 0.0877A (LaIII) to 0.2943A (HoIII). These tricationic 15-metallacrown-5 complexes have potential as anion recognition agents. These complexes interact through their hydrophobic benzyl groups, forming dimers that have a chiral hydrophobic pocket (Ln-Ln ∼ 11.5A). Crystal structures show that saturated aliphatic dicarboxylates do not enter this cavity, coordinating to the lanthanide ion only on the hydrophilic faces of the metallacrowns. Maleate, a short unsaturated dicarboxylate, enters the hydrophobic pocket without spanning it, while terephthalate, an aromatic dicarboxylate, enters the pocket and spans it, forming a perfect match to the pocket in both size and functionality. 15-Metallacrown-5 complexes made with tyrosine hydroxamic acid form a coordinated dimer, with a contracted pocket (Ln-Ln ∼ 8.5A). In this case, nitrate anions bind preferentially to Cu II ions in the cavity, spanning it, while chloride anions bridge adjacent dimers of metallacrowns, coordinating only to CuII ions on the hydrophilic faces. Helical structures are generating interest in the field of materials science. 15-metallacrown-5 pheHA complexes act as chiral molecular building blocks to form self-assembled infinite helical chains of metallacrowns. Containing a single enantiomer, the structures presented here are significant because the enantiomer (P or M) of the helix is determined by the enantiomer of the ligand used to make the metallacrown. While an important goal in this field is to form resolved P or M helices in non-centrosymmetric solids, unresolved infinite helices existing as racemates are typically recovered.

The purpose of this research has been to explore the role of agent certification in the process of global sourcing. While some research has been done in the area of exporter-intermediary relationship, little has been done to study the importance of buyer-agent relationship and how the process of agent certification could strengthen that relationship. Global sourcing has played a vital role in the existence of textile and apparel industries across the world. With the increased advancement of developing countries and the numerous advantages that these countries possess, developed countries, such as the United States and countries in the European sub-continent, rely heavily on global sourcing to remain competitive in the global marketplace. Due to numerous barriers to global sourcing such as language barriers and inability to check sources, companies have found it useful to source through agents. These agents act as the facilitators between the sources and the buyers. With the advent of Internet and e-commerce, online sourcing has come into picture. Although the transparency in terms of sources and buyers on the web and their processes has increased and organizations are thinking of certifying sources, the role of agents' sill exists. A total of 30 agents and apparel-manufacturing buyers were interviewed to assess the feasibility and role of agent certification in the global sourcing process. While the specific items to be certified were not confirmed, both types of subjects agreed that agent certification would assist in the transactions in the buyer-agent relationship. It was found that small and medium-sized buyers would find agent certification more useful than large-sized buyers because of small-size buyers' limited resources and potential to find trusted agents.

Patients with acquired immunodeficiency syndrome (AIDS) or post-transplant patients are at risk for the development of Epstein-Barr Virus (EBV)-associated immunoblastic B cell lymphomas (IBL). Chemotherapy has had limited efficacy in the treatment of EBV-associated IBL. Differentiation therapy is an alternative to traditional chemotherapy that induces terminal differentiation of malignant cells into mature, non-replicating cells. Five agents (retinoic acid, sodium butyrate, trichostatin A, bryostatin and TGF-beta1) that have been shown to induce differentiation in other hematopoietic cell lines were screened for their ability to decrease proliferation and/or induce terminal differentiation in lymphoblastoid cell lines (LCL), an in vitro model for IBL. The drugs that decreased proliferation (retinoic acid, sodium butyrate and trichostatin A) were further examined to determine whether or not proliferation was reduced by the induction of terminal differentiation, cell cycle arrest, apoptosis or changes in viral gene expression. Sodium butyrate (SB) and trichostatin A (TSA) induced cell cycle arrest and apoptosis without the induction of terminal differentiation. In contrast all-trans retinoic acid (ATRA), a natural derivative of retinoic acid, arrested cells in the G1 compartment of the cell cycle and induced differentiation in a subset of LCL. When used in combination, TSA potentiated the effects of ATRA, synergistically producing G1 arrest, promoting apoptosis and inducing terminal differentiation. Our preliminary results suggest that combination treatment with ATRA and TSA may hold great promise in the future of differentiation therapy for EBV-associated IBL. To determine if ATRA and SB could inhibit growth of LCL in vivo , SCID mice were injected with the EW LCL and mice were given subcutaneous drug pellets or placebo pellets at the time of intraperitoneal inoculation. SB treatment was ineffective, due to its short half-life in vivo. However, morbid tumor burdens arose 4 days earlier for untreated (n = 21) and placebo-implanted (n = 13) mice compared with ATRA-treated (n = 15) mice. No differences in patterns of viral gene expression or the phenotype of the tumors were found thus suggesting that ATRA treatment affected only a subset of cells. This data provides evidence that retinoids may have potential as an in vivo therapeutic treatment for EBV-associated IBL.

The goal of gene therapy is to deliver a foreign gene to mammalian cells to treat a variety of diseases. To be effective, the gene must be stable in blood and enter the cell's cytosol after crossing the cellular membrane. However, because DNA is rapidly degraded in the blood and is unable to translocate across the cellular membrane, carrier molecules that bind to DNA and mediate these functions must be developed. This thesis proposed to establish a new class of low molecular weight peptides that stabilize DNA and deliver it to the cytosol to increase the level of gene expression. Initial studies to develop a low molecular weight peptide for gene delivery identified a sequence consisting of a single cysteine, tryptophan and eighteen lysine residues (Cys-Trp-Lys18) that bound to DNA electrostatically to form small condensates. While effective for in vitro gene transfer, this peptide proved to be ineffective at stabilizing DNA in vivo due to its rapid dissociation from the peptide in the circulation. To overcome this, Cys-Trp-Lys18 was improved by substituting multiple cysteine residues for lysine. The resulting sulfhydryl cross-linking peptides oxidized forming multiple interpeptide disulfide bonds in the presence of DNA. Condensates formed by sulfhydryl cross-linking peptides were small, highly stable and mediated high levels of in vitro gene transfer. This concept was used to define a minimal peptide that contained four lysines and two cysteine residues (Cys-Lys4-Cys), which formed DNA condensates that mediated high levels of gene expression in vitro. Substitution of histidine into a low molecular weight sulfhydryl cross-linking peptide (Cys-His-Lys6-His-Cys) proved effective in further enhancing gene expression by promoting endosomal escape of the DNA condensates. The results presented in this thesis demonstrate the novel concept of sulfhydryl cross-linking peptides and establish for the first time that hexapeptides are sufficient to deliver plasmid DNA to mammalian cells to mediate high levels of gene expression. These studies should provide a foundation on which to develop chemically well-defined nonviral gene delivery agents for the treatment of human diseases.

TD-50 A Thesis presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Forestry, Fisheries and Wildlife, Under the Supervision of Professor Ron J. Johnson. Lincoln, Nebraska: December, 1985. Copyright (c) 1985 Bobbi A. Holm

One of the basic considerations in the design of autonomous agents is the competence of the agent when presented with many tasks to perform. This thesis demonstrates the need for meta-level control in the task domain of multi-tasking autonomous agents in dynamic environments. It provides the mechanisms to achieve merging of tasks during the execution phase applying methods usually used in opportunistic planning. In a multi-tasking environment, an autonomous agent faces, not only the difficulty of acting and reacting in the external world, but also the burden of performing more than a single task at the same time. This requires that at every point during execution the agent be capable of attending all the tasks it performs. The idea is that an agent has control in its task domain if at any point during execution it can choose its next action out of the set of all tasks it performs. This effects to an emergent meta-level control that is task independent. Two characteristics are important to the success of merging tasks execution: The right decomposition of tasks and the interaction between the tasks. The better the decomposition, the more the agent is able to intermix tasks actions. The more tasks share knowledge, the more the agent benefits from merging; by elimination of redundant actions, by resolution of conflicting actions and by a seemingly parallel execution of multiple tasks. The advantages of the merging mechanism are demonstrated in two task domains. First it is implemented and tested in the blocks world. The results show improved performance in the number of external actions taken by the agent compared to the performance in the same task set without merging. The mechanism is then implemented in a more complex domain which has most of the characteristics of realistic dynamic and unpredictable environments. It is shown that merging of tasks execution in this domain enables the agent to cope with unpredictable events without having to resort to traditional planning techniques.

Radioiodinated analogs of the naturally-occurring alkyl lysophospholipid (ALP) were designed and synthesized for evaluation as potential tumor-specific imaging agents. Tumor-specific imaging agents are radiopharmaceuticals which localize within a tumor and thereby provide a positive image of the tumor. In order to achieve this selective accumulation, the ALP analogs chosen for synthesis were based on an understanding of the biochemical synthesis and/or metabolism of natural ether phospholipids and the pharmacological actions of synthetic analogs. The five iodinated ALP analogs synthesized were rac-1-O- (12-(m-iodophenyl)dodecyl) glycero-3-phosphocholine, ET-12IP-OH; rac-1-O- (12-(m-iodophenyl)dodecyl) -2-O-methylglycero-3-phosphocholine, ET-12IP-OMe; rac-1-O- (12-(m-iodophenyl)dodecyl) propane-1,3-diol-3-phosphocholine, ET-12IP-H; rac-1-O-hexadecyl-2-O-(m-iodobenzoyl)glycero-3-phosphocholine, ET-16-IBz and rac-1-O-hexadecyl-2-O-(m-iodobenzyl)-glycero-3-phosphocholine, ET-16-IBn. Four analogs, ET-12IP-OMe, ET-12IP-H, ET-16-IBz and ET-16-IBn were radiolabelled with iodine-125 in moderate yields via an isotope exchange procedure. ($\sp{125}$I) ET-12IP-OMe, ($\sp{125}$I) ET-12IP-H and ($\sp{125}$I) ET-16-IBz were evaluated in tissue distribution (TD) studies involving both normal and tumor-bearing rats. The tumor chosen for this study was the Walker 256 sarcoma which was implanted in the thigh. The TD results revealed that the radiolabelled ALP analogs exhibited different accumulation patterns. Following intravenous (IV) administration of ($\sp{125}$I) ET-12IP-OMe and ($\sp{125}$I) ET-12IP-H, an immediate and sustained uptake of radioactivity within the tumor was observed with the greatest accumulation of radioactivity appearing after administration of ($\sp{125}$I) ET-12IP-OMe. In contrast, a much slower and lower accumulation of radioactivity within the tumor was found for ($\sp{125}$I) ET-16-IBz. Although, clearance of radioactivity from the nontarget tissues occurred with time, clearance in the tumor was delayed for ($\sp{125}$I) ET-12IP-OMe and ($\sp{125}$I) ET-12IP-H. This difference in clearance from the tumor vis-a-vis other tissues afforded an appropriate tumor to nontumor ratio. On the other hand, the level of radioactivity within the tumor following administration of ($\sp{125}$I) ET-16-IBz was not appreciably different from that of normal tissues. Based upon the TD results and the tumor to nontumor ratios, ($\sp{125}$I) ET-12IP-OMe was selected for scintigraphic studies with rats bearing the Walker 256 sarcoma. Twenty-four hours following administration of the radiolabeled ALP analog, external imaging with a gamma-camera clearly delineated the tumor.

The purpose of this thesis project was to design, synthesize, and evaluate various radiologic agents for their ability to visualize small hepatic tumors and to evaluate hepatic function. Our strategy for the site-specific delivery of hepatographic agents was based mainly on a biochemical approach whereby naturally-occurring compounds known to be stored and/or synthesized in the liver serve as carriers for the radiologic probe. Therefore, on the basis of the known metabolic fate of lipids, triacylglycerols were viewed as appropriate liver-specific carrier molecules for the synthesis of hepatic-imaging agents. Accordingly, a series of (omega)-(3-amino-2,4,6-triiodophenyl)-alkanoate esters of glycerol was synthesized and evaluated in rats. The acid precursors, (omega)-(3-amino-2,4,6-triiodophenyl)-acetic and propionic acids, were synthesized by modified literature procedures. The longer-chain acid precursors were obtained by Wittig condensation of either 3-nitrobenzaldehyde with the appropriate alkylidenetriphenylphosphoran or, conversely, 3-nitrobenzyltriphenylphosphoran with an appropriate (omega)-oxoalkanoate. This afforded the respective nitrophenyl-dodecenoate and heptadecenoate esters which upon reduction, iodination and saponification gave the corresponding (omega)-(3-amino-2,4,6-triiodophenyl)-dodecanoic and heptadecanoic acids. Each of these four acids and iopanoic acid were used to esterify glyceryl 1,3-dipalmitate to furnish a series of glyceryl 1,3-dipalmitoyl 2-(omega)-(3-amino-2,4,6-triiodophenyl)-alkanoates. Similarly, esterification of 2-monopalmitin with two equivalents of each acid afforded a series of glyceryl 2-palmitoyl 1,3-di-(omega)-(3-amino-2,4,6-triiodophenyl)-alkanoates. In addition, a series of glyceryl 1,2,3-tri-(omega)-(3-amino-2,4,6-triiodophenyl)-alkanoates were prepared by esterification of the glyceryl 1,3-di-(omega)-(3-amino-2,4,6-triiodophenyl)-alkanoate intermediate or glycerol with one or three equivalents of iodinated acid, respectively. Following radioiodination with iodine-125 in a melt of pivalic acid, the radiolabeled derivatives were evaluated in rats for their ability to selectively localize in the liver. Of the 19 target compounds synthesized and evaluated, glyceryl 1,2,3-tri-3-(3-amino-2,4,6-triiodophenyl)-propanoate displayed rapid and sustained liver specificity. This agent was found to accumulate in the liver in concentrations of 67, 75, and 86% of the administered dose at 5 min, 30 min, and 24h, respectively. Moreover, the 24h liver to blood ratio of 235 was the most impressive of all compounds evaluated. Based on these preliminary results, further preclinical scintigraphic and CT studies in higher animal species are warranted with this agent.

Our research is aimed at providing agents with the ability to use observations of actions taken by others not only to recognize current actions but also to infer ongoing plans and goals, a process called plan recognition. Once our agents can recognize the plans and goals of others, they can then employ a number of techniques for coordinating their planned actions with those of others. Multi-agent coordination has typically been performed using explicit communication between agents. Plan recognition offers several potential advantages over explicit communication however, including lower communication overhead, higher reliability, greater information content, and robustness in the face of agents who are not forthcoming about their plans. On the other hand, it also has potential disadvantages, including the fact that agents need to know how other agents act in pursuit of their goals, that actions might not be accurately observable or might support multiple possible plans, and that inferring the plans of others can be more time consuming than being told explicitly by them. In this research, we have developed a probabilistic plan recognition model called a plan recognition network (PRN) and a computational system called ASPRN (Automated Synthesis of Plan Recognition Networks) that can automatically construct a PRN from a plan model. PRNs provide an observing agent with a wide range of inferred information and handle the uncertainty associated with plan recognition and observations in a natural, robust manner. We demonstrate that plan recognition can be done in a competitive, real-time, simulated environment such that plan recognizing agents win up to 90% of the time, despite the inherent overhead and uncertainty of the recognition process. Our experiments reveal that even though PRNs provide numeric information, they may currently be more amenable to symbolic reasoning method than decision-theoretic approaches. Other experiments highlight that waiting for plan recognition information to become more certain before acting upon it reduces coordination performance because of the delay before imitation of coordination activities. Analysis of our experiments also highlights that the temporal distribution of observations while performing plan recognition has a distinctly negative impact upon the observing agent's ability to effectively coordinate as the distribution is pushed later toward the end of plan execution. Lastly, our experiments show us that coordinating agents can take advantage of plans with early plan disambiguation points and that plans with late plan disambignation points may hinder effective plan recognition-based coordination.