Search

The sparse literature on the use of imperatives in research papers suggests that they are relatively common in a small number of disciplines, but rare, if used at all, in others. The present study addresses the use of imperatives in a corpus of upper-level A-graded student papers from 16 disciplines. A total of 822 papers collected within the past 5 years were analyzed for imperative use, with particular emphasis placed on the main text of papers from the five disciplines with the highest proportion of imperatives. In each of these disciplines, text-based interviews were conducted with faculty members to establish disciplinary contexts. Results show that imperatives are used frequently in physics, philosophy, economics, mechanical engineering, and linguistics, though in quite varying ways. The interview data suggest that successful and experienced student writers adopt the potentially 'high risk strategy' (Hyland 2012) of initiating a sentence with an imperative for various strategic purposes that are discipline-specific. Such insights have implications for writing instructors and materials designers in both L1 and L2 contexts. [ABSTRACT FROM AUTHOR]

Abstract: Combining the techniques of paper prototyping and card sorting into a single session has the benefits of helping users to understand a new technology on the one hand, and of gaining insight into the users’ mental models of that technology on the other hand. However, acquainting users with a new technology via a paper prototype might affect their mental models, as assessed with the card sorting technique. The aim of this paper was to explore the possibility of combining the two techniques in a single research session. Thirty-seven users participated in a study concerning a payment system based on Near Field Communication (NFC). Eight group sessions were organized, including both a paper prototyping exercise and a card sorting exercise. The order of the exercises was alternated. The findings of this case study seem to suggest that the paper prototyping exercise resulted into deeper insights into the participants’ mental models resulting from the card sorting exercise. At the same time, paper prototyping seemed to prevent participants to come up with new names for their card sorting categories. [Copyright &y& Elsevier]

Motivation Accurately predicting the likelihood of interaction between two objects (compound–protein sequence, user–item, author–paper, etc.) is a fundamental problem in Computer Science. Current deep-learning models rely on learning accurate representations of the interacting objects. Importantly, relationships between the interacting objects, or features of the interaction, offer an opportunity to partition the data to create multi-views of the interacting objects. The resulting congruent and non-congruent views can then be exploited via contrastive learning techniques to learn enhanced representations of the objects. Results We present a novel method, Contrastive Stratification for Interaction Prediction (CSI), to stratify (partition) a dataset in a manner that can be exploited via Contrastive Multiview Coding to learn embeddings that maximize the mutual information across congruent data views. CSI assigns a key and multiple views to each data point, where data partitions under a particular key form congruent views of the data. We showcase the effectiveness of CSI by applying it to the compound–protein sequence interaction prediction problem, a pressing problem whose solution promises to expedite drug delivery (drug–protein interaction prediction), metabolic engineering, and synthetic biology (compound–enzyme interaction prediction) applications. Comparing CSI with a baseline model that does not utilize data stratification and contrastive learning, and show gains in average precision ranging from 13.7% to 39% using compounds and sequences as keys across multiple drug–target and enzymatic datasets, and gains ranging from 16.9% to 63% using reaction features as keys across enzymatic datasets. Availability and implementation Code and dataset available at https://github.com/HassounLab/CSI. [ABSTRACT FROM AUTHOR]

The stream ciphers RCR-64 and RCR-32 designed by Sekar et al. are the most recent additions to the Py-family of stream ciphers, originally designed by Biham et al. The ciphers are among the fastest stream ciphers on software. To the best of our knowledge, the only reported attacks on the ciphers are due to Ding et al. , published in the Journal of Universal Computer Science. In this paper, we review these alleged attacks on the RCR ciphers and show that they are based on non-existent keystream biases stemming from flawed probability calculations. [ABSTRACT FROM AUTHOR]

In this paper, we explore the use of spatial clustering algorithms as a new computational approach for modelling the cosmic web. We demonstrate that such algorithms are efficient in terms of computing time needed. We explore three distinct spatial methods which we suitably adjust for (i) detecting the topology of the cosmic web and (ii) categorizing various cosmic structures as voids, walls, clusters, and superclusters based on a variety of topological and physical criteria such as the physical distance between objects, their masses, and local densities. The methods explored are (1) a new spatial method called Gravity Lattice ; (2) a modified version of another spatial clustering algorithm, the abacus ; and (3) the well known spatial clustering algorithm hdbscan. We utilize hdbscan in order to detect cosmic structures and categorize them using their overdensity. We demonstrate that the abacus method can be combined with the classic dtfe method to obtain similar results in terms of the achieved accuracy with about an order of magnitude less computation time. To further solidify our claims, we draw insights from the computer science domain and compare the quality of the results with and without the application of our method. Finally, we further extend our experiments and verify their effectiveness by showing their ability to scale well with different cosmic web structures that formed at different redshifts. [ABSTRACT FROM AUTHOR]

Artificial intelligence is one of the most trending topics in the field of Computer Science which aims to make machines and computers 'smart'. There are multiple diverse technical and specialized research associated with it. Due to the accelerating rate of technological changes, artificial intelligence has taken over a lot of human jobs and is giving excellent results that are more efficient and effective, than humans. However, a lot of time there has been a concern about the following: will artificial intelligence surpass human intelligence in the near future? Are computers' ever accelerating abilities to outpace human jobs and skills a matter of concern? The different views and myths on the subject have made it even a more than just a topic of discussion.   In this research paper, we will study the existing facts and literature to understand the true definitions of artificial intelligence (AI) and human intelligence (HI) by classifying each of its types separately and analyzing the extent of their full capabilities. Later, we will discuss the possibilities if AI eventually can replace human jobs in the market. Finally, we will synthesize and summarize results and findings of why artificial intelligence cannot surpass human intelligence completely in the future. [ABSTRACT FROM AUTHOR]

The recent years have witnessed a rapid increase in the number of scientific articles in biomedical domain. These literature are mostly available and readily accessible in electronic format. The domain knowledge hidden in them is critical for biomedical research and applications, which makes biomedical literature mining (BLM) techniques highly demanding. Numerous efforts have been made on this topic from both biomedical informatics (BMI) and computer science (CS) communities. The BMI community focuses more on the concrete application problems and thus prefer more interpretable and descriptive methods, while the CS community chases more on superior performance and generalization ability, thus more sophisticated and universal models are developed. The goal of this paper is to provide a review of the recent advances in BLM from both communities and inspire new research directions. [ABSTRACT FROM AUTHOR]

It has been more than 10 years since Satoshi Nakamoto published his famous paper entitled 'Bitcoin: a peer-to-peer electronic cash system', which set the foundation of blockchain technology. Accompanied by the price volatility of bitcoins from 2017 to 2018, blockchain has been a hot word on the internet, and particularly hot in China. Blockchain offers a distributed and secure system for data storage and value transactions. Its applications are springing up in multiple fields. The Chinese government is considering these trends with great caution. Initial coin offering has been banned in China since September 2017. By contrast, an official white paper on China's blockchain technology, which was released in May 2018, said that blockchain technology will be widely applied in the real economy of China within 3 years. In a recent panel discussion held by National Science Review, experts talked about related topics. Their opinions may provide a quick view of the future development of blockchain in China and abroad. Jing Chen Assistant Professor of Computer Science Department, Stony Brook University and Chief Scientist at Algorand LLC, USA Xiaotie Deng Professor of School of Electronics Engineering and Computer Science, Peking University, China Guohua Gan Vice President of Beijing Tai Cloud Technology Corp. China Xiaoyun Wang Professor of Institute of Advanced Study, Tsinghua University, China Zhiming Zheng Professor of School of Mathematics and Systems Science, Beihang University, China Lei Guo (Chair) Professor of Academy of Mathematics and Systems Science, Chinese Academy of Sciences, China [ABSTRACT FROM AUTHOR]

Estimating eigenvectors and low-dimensional subspaces is of central importance for numerous problems in statistics, computer science and applied mathematics. In this paper we characterize the behaviour of perturbed eigenvectors for a range of signal-plus-noise matrix models encountered in statistical and random-matrix-theoretic settings. We establish both first-order approximation results, i.e. sharp deviations, and second-order distributional limit theory, i.e. fluctuations. The concise methodology presented in this paper synthesizes tools rooted in two core concepts, namely deterministic decompositions of matrix perturbations and probabilistic matrix concentration phenomena. We illustrate our theoretical results with simulation examples involving stochastic block model random graphs. [ABSTRACT FROM AUTHOR]

The mixing time of random walks on a graph has found broad applications across both theoretical and practical aspects of computer science, with the application effects depending on the behavior of mixing time. It is extensively believed that real-world networks, especially social networks, are fast mixing with their mixing time at most |$O(\log N)$| where |$N$| is the number of vertices. However, the behavior of mixing time in the real-life networks has not been examined carefully, and exactly analytical research for mixing time in models mimicking real networks is still lacking. In this paper, we first experimentally evaluate the mixing time of various real-world networks with scale-free small-world properties and show that their mixing time is much higher than anticipated. To better understand the behavior of the mixing time for real-world networks, we then analytically study the mixing time of the Apollonian network, which is simultaneously scale-free and small-world. To this end, we derive the recursive relations for all eigenvalues, especially the second largest eigenvalue modulus of the transition matrix, based on which we deduce a lower bound for the mixing time of the Apollonian network, which approximately scales sublinearly with |$N$|⁠. Our results indicate that real-world networks are not always fast mixing, which has potential implications in the design of algorithms related to mixing time. [ABSTRACT FROM AUTHOR]

Computational complexity theory is a subfield of computer science originating in computability theory and the study of algorithms for solving practical mathematical problems. Amongst its aims is classifying problems by their degree of difficulty — i.e. , how hard they are to solve computationally. This paper highlights the significance of complexity theory relative to questions traditionally asked by philosophers of mathematics while also attempting to isolate some new ones — e.g. , about the notion of feasibility in mathematics, the |$\mathbf{P} \neq \mathbf{NP}$| problem and why it has proven hard to resolve, and the role of non-classical modes of computation and proof. [ABSTRACT FROM AUTHOR]

Purpose. Results of the 2013 ASHP national survey on informatics are presented. Methods. Pharmacy directors from all types and sizes of U.S. hospitals were included in the sample of 4893 individuals invited to participate in an online survey. The survey contained over 600 data elements that addressed the adoption and use of a variety of pharmacy informatics and technology. Data were analyzed by hospital type and size, accounting for sampling procedures and differences in response rate. Results. Of the 4893 surveys distributed, 465 usable surveys were returned, yielding a response rate of 9.5%. Nearly 33% of hospitals reported having a complete electronic health record (EHR) (i.e., no paper charts). Adoption rates for computerized prescriber order entry, clinical decision support, electronic prescribing, and barcode- assisted medication administration indicated that these technologies are clear priorities. Nearly half of respondents indi- Brent I. Fox, Pharm.D., Ph.D., is Associate Professor, Department of Health Outcomes Research and Policy, Harrison School of Pharmacy, Auburn University, Auburn, AL. Craig A. Pedersen, B.S.Pharm., Ph.D., FAPhA, is Pharmacy Manager, Confluence Health—Central Washington Hospital, Wenatchee. Karl F. Gumpp er, B.S.Pharm., BCPS, CPHIMS, FASHP, is Pharmacy Informatics Manager, Department of Pharmacy, Boston Children's Hospital, Boston, MA; at the time of writing he was Director, Section of Pharmacy Informatics and Technology, American Society of Health-System Pharmacists, Bethesda, MD. Address correspondence to Dr. Fox (foxbren@auburn.edu). The authors have declared no potential conflicts of interest. Copyright © 2015, American Society of Health-System Pharmacists, Inc. All rights reserved. 1079-2082/15/0402-0636. DOI 10.2146/ajhp140274 cated using solely paper-based medication reconciliation processes, while almost as many reported using processes that combined electronic and paper methods. Overall, automated dispensing cabinets were more common in U.S. hospitals than were carousels and dispensing robots. The adoption of patient portals and personal health records is becoming common. Technologies identified as enablers of the Pharmacy Practice Model Initiative (PPMI) were found in at least 25% of hospitals. The average total number of pharmacy information technology full-time equivalents was 3.12. Conclusion. This survey found widespread use of pharmacy informatics and technology across the entire medicationuse process. Considerable progress was demonstrated in meeting meaningful-use measures for EHRs and meeting the recommendations of the ASHP PPMI. [ABSTRACT FROM AUTHOR]

Studying the setup and development of an initiative of computer clubs in intercultural neighborhoods, this paper builds on the theory and method associated with value sensitive design to account for the use of off-the-shelf technology in a diverse cultural context, and over an extended period of time. We present three cases from one of these computer clubs, each at a different point in time in the club's development. Central factors are identified that impact the course of a socio-technical initiative. We highlight the challenges inherent in matching existing ICT with the values both explicitly identified in the initiative and which evolve over time. Our study highlights the relevance of open communication structures among researchers and local practitioners, as well as methodological support that is needed to span a wide range of user experiences. Both aspects are key to making value sensitive design a lived experience on the diverse community level. [ABSTRACT FROM AUTHOR]

Confidentiality, integrity and availability, while being key requirements for ensuring security, have had limitations in providing an integral security model that incorporates the benefits of all predominant designs. Heeding to the call that security models cater to unique operational characteristics of individual firms, this paper presents a deep structure framework of information systems (ISs) security. The framework incorporates three models—representational model, which identifies subsystems within an organization; state-tracking model, which ensures that different states trace IS security in the real world;nd the decomposition model, which defines specific external events that are a stimuli to changes in internal events. In a final synthesis, the paper presents a deep structure-based conceptual clarity that manifests the meaning of dynamic, custom-fit and flexible IS security solutions. [ABSTRACT FROM AUTHOR]

Abstract: Attentive reading is a complex and cognitively demanding task that uses note-taking and annotation to support the reader’s interpretation of the document. When reading on paper, extensive use of highlighting and other activities are conducted to support attentive reading, but this rich behaviour is not used with digital documents. Many users therefore print digital documents and then interact with them in physical form. This paper presents the “Digital Reading Desk,” an enhanced digital reading environment that provides support for attentive reading, providing a large working space for notes that mimics the use of desk space in a conventional physical environment. The Reading Desk uses a single tool to support both annotation and bookmarking, simplifying both the user’s learning of the system and their use of tools. Evaluation of the Reading Desk indicates preference for it, as well as considerable behavioural differences between our approach and traditional digital reading tools. [Copyright &y& Elsevier]

This paper examines three ideas: First, the traditional relationship between a science, the mathematics it uses and the engineering based on it. Second, the nature of (software) computer science, which may not be a science at all, and its unusual use of mathematics. And finally, the nature of software engineering, its relationship with computer science, and its use of mathematics called ‘formal methods’. These three ideas turn on the first of them, since the scientific world view seems natural for the study of computing. The paper's thesis is that while software touches science in many ways, it does not itself have a significant scientific component. For understanding programming, for teaching it and for applying it in the world, science is the wrong model. Mathematics has found its own foundations apart from science, and computer science must do the same. [ABSTRACT FROM AUTHOR]

Signposts make complex documents more flexible and easier to read; signposts exist in many forms, but are familiar as cross references and as hypertext links. Signposting systems need to be carefully designed, so that they are reliable, easy to use for readers yet convenient for authors to embed in their writing. There are fundamental problems in achieving good signposting, which this paper explores through cross-referencing in the popular medium of LaTeX, which is often the typesetting system of choice for heavily cross-referenced documents. This paper provides an implementation of cross references for LaTeX users. Problems with LaTeX and TeX arise, and are explored and mostly solved: some problems are due to the designs of these systems, but, crucially, some problems are unavoidable, an inevitable part of signposting in principle, whatever systems are used, even including the web. [ABSTRACT FROM AUTHOR]

A policy for a minimal reactive agent is a set of condition-action rules used to determine its response to perceived environmental stimuli. When the policy pre-disposes the agent to achieving a stipulated goal we call it a teleo-reactive policy. This paper presents a framework for constructing and evaluating teleo-reactive policies for one or more minimal agents, based upon discounted-reward evaluation of policy-restricted subgraphs of complete situation graphs. The main feature of the method is that it exploits explicit associations of the agent's perceptions with states. The framework allows to construct and evaluate policies for a number of cooperating agents by focusing upon the behaviour of a single representative of them. This abstraction ameliorates the potential combinatorial burden. Within the framework varied behaviours can be modelled, including communication between agents. Simulation results presented here indicate that the method affords a good degree of predictive power. The paper presents two different branch and bound algorithms used to optimize policy evaluation. [ABSTRACT FROM PUBLISHER]

Energy efficiency is increasingly important for future information and communication technologies (ICT), because the increased usage of ICT, together with increasing energy costs and the need to reduce green house gas emissions call for energy-efficient technologies that decrease the overall energy consumption of computation, storage and communications. Cloud computing has recently received considerable attention, as a promising approach for delivering ICT services by improving the utilization of data centre resources. In principle, cloud computing can be an inherently energy-efficient technology for ICT provided that its potential for significant energy savings that have so far focused on hardware aspects, can be fully explored with respect to system operation and networking aspects. Thus this paper, in the context of cloud computing, reviews the usage of methods and technologies currently used for energy-efficient operation of computer hardware and network infrastructure. After surveying some of the current best practice and relevant literature in this area, this paper identifies some of the remaining key research challenges that arise when such energy-saving techniques are extended for use in cloud computing environments. [ABSTRACT FROM PUBLISHER]

Abstract: This paper represents a personal view of the state of HCI as a design discipline and as a scientific discipline, and how this is changing in the face of new technological and social situations. Going back 20years a frequent topic of discussion was whether HCI was a ‘discipline’. It is unclear whether this was ever a fruitful topic, but academic disciplines are effectively about academic communities and there is ample evidence of the long-term stability of the international HCI/CHI community. However, as in computer ‘science’, the central scientific core of HCI is perhaps still unclear; for example, a strength of HCI is the closeness between theory and practice, but the corresponding danger is that the two are often confused. The paper focuses particularly on the challenge of methodological thinking in HCI, especially as the technological and social context of HCI rapidly changes. This is set alongside two other challenges: the development of reliable knowledge in HCI and the clear understanding of interlinked human roles within the discipline. As a case study of the need for methodological thinking, the paper considers the use of single person studies in research and design. These are likely to be particularly valuable as we move from a small number of applications used by many people to a ‘long tail’ where large numbers of applications are used by small numbers of people. This change calls for different practical design strategies; focusing on the peak experience of a few rather than acceptable performance for many. Moving back to the broader picture, as we see more diversity both in terms of types of systems and kinds of concerns, this may also be an opportunity to reflect on what is core across these; potential fragmentation becoming a locus to understand more clearly what defines HCI, not just for the things we see now, but for the future that we cannot see. [Copyright &y& Elsevier]

Due to the increasing scale and complexity of software products, software maintenance especially on bug resolution has become a challenging task. Generally in large-scale software programs, developers depend on software artifacts (e.g., bug report, source code and change history) in bug repositories to complete the bug resolution task. However, a mountain of submitted bug reports every day increase the developers' workload. Therefore, 'How to effectively resolve software defects by utilizing software artifacts?' becomes a research hotspot in software maintenance. Considerable studies have been done on bug resolution by using multi-techniques, which cover data mining, machine learning and natural language processing. In this paper, we present a literature survey on tasks, challenges and future directions of bug resolution in software maintenance process. Our investigation concerns the most important phases in bug resolution, including bug understanding, bug triage and bug fixing. Moreover, we present the advantages and disadvantages of each study. Finally, based on the investigation and comparison results, we propose the future research directions of bug resolution. [ABSTRACT FROM AUTHOR]

The prevalence of heterogeneous manycore processors has been shown as a promising alternative to web-based data parallel MapReduce applications. The differences of manycore from multicore raise new challenges to designing and implementing efficient and scalable MapReduce applications, such as memory access congestion. This paper argues that it is more efficient using multiple small groups of cores than using a single group with all cores to address these challenges. We propose a group-based MapReduce implementation, called Grouped-MapReduce (GMR). It uses grouping to align tasks so that the tasks in each group are congestion-free. Further, it uses multiplexing to control the implementation of groups so that multiple groups can efficiently share the limited memory bandwidth without causing serious memory access congestion. We have implemented a prototype of GMR based on Phoenix++, an already highly optimized MapReduce runtime. Experiments on six benchmarks show that GMR implements and scales well on manycore systems and obtains an impressive improvement over Phoenix++ from 1.04x to 1.77x without artificially tuning the existing application code. [ABSTRACT FROM AUTHOR]

Reversible data hiding (RDH) algorithms are concerned with the recovery of the original cover image upon the extraction of the secret data. In some RDH algorithms, embedding and extraction are performed through modifying the histogram of prediction errors that are computed using certain predictors. However, the embedding capacity and image quality in these algorithms are dependent on the characteristics of a single predictor. In this paper, we propose the idea of employing multiple predictors in order to increase the embedding capacity. The idea of multiple predictors is integrated in the modification of prediction errors algorithm without adding any overhead regarding the predictor that is used for embedding at each pixel in the image. The selection of the accurate predictor depends on the polarity of the prediction errors from all predictors. Experimental results proved the efficiency of the proposed algorithm in terms of increasing the embedding capacity and producing competitive quantitative and qualitative quality of the stego image when compared with recent algorithms. [ABSTRACT FROM AUTHOR]

To solve the problem of group task allocation with time constraints in open and dynamic network environments, this paper proposes a decentralized combinatorial auction-based approach for group task allocation. In the proposed approach, both resource providers and consumers are modeled as intelligent agents. The proposed approach is decentralized, so all the agents are limited to communicating with their neighboring agents. The proposed approach also allows agents to enter and leave the network environments freely, and is robust for the dynamism and openness of the network environments. Tasks in the proposed approach have deadlines, and may need the collaboration of a group of self-interested providers. The experimental results demonstrate that the proposed approach outperforms two well-known task allocation approaches in terms of success rate of task allocation, the individual utility of the agents, the speed of task allocation and scalability. [ABSTRACT FROM AUTHOR]

The motif discovery problem (MDP) is an important biological optimization problem that has been addressed in numerous ways. However, it is important to note that when we address real complex optimization problems, we should adequately formulate them in order to provide real applicability to the developed techniques. In the particular case of MDP, as we do not know the size of the motifs and the number of repetitions that can be found in the sequences, we must not make any length or pattern-repetition assumptions. In addition, if we consider that it is practically impossible to adequately formulate an optimization problem with a single-objective function formulation, multiobjective optimization can be a good methodology to be considered. In this paper, we propose a novel hybrid multiobjective algorithm for tackling the MDP. Our main objective is to study the results achieved by our algorithm, analysing its performance when different motif occurrence models are considered. As we will see, experimental results on different sets of real instances will point out the advantages and disadvantages of each model, also checking how a more realistic definition of the optimized problem provides better quality biological results. [ABSTRACT FROM AUTHOR]

Preferences have been widely studied in several areas including computer science, as they play an important role in many computational tasks, such as decision making support, providing recommendations and personalizing applications. Although many approaches consider particular preference representation models to be used as input for algorithms to address these tasks, there is a need for identifying a model that provides adequate constructions for users to express their preferences. In this paper, we propose a preference meta-model that provides various preference constructs, which include end-user expressions. We start by describing an exploratory study of how people express their preferences in natural language, which provides the basis for the meta-model. After describing the meta-model, we evaluate it with two user studies in different domains. The results of this evaluation indicate that the preference statements that can be expressed with the meta-model are adequate for allowing users to indicate their preferences to a computational system. [ABSTRACT FROM PUBLISHER]

IEEE 802.22 wireless regional area network (WRAN) is a cognitive radio-based network. WRANs are intended to be deployed by different service providers and designed to opportunistically utilize the unused TV bands. WRANs have to self-coexist with other overlapped WRANs in a distributed manner. Therefore, every service provider tries to acquire a band free of interference from others to satisfy a required quality of service. This self-coexistence problem is one of the major challenges in WRAN. In this paper, we propose a Markov-based distributed approach for mitigating this problem. We model the problem as an absorbing discrete-time Markov chain. In this model, if two or more overlapped WRANs select the same band, then each one should either stay or switch to another band according to a certain switching probability. This process continues until each one of the WRANs finds an interference-free band. In this case, the Markov chain reaches the absorbing state. This model is employed to find the optimal switching probability, which in turn minimizes the time required to reach the absorbing state. The switching probability is numerically found as a function of the number of overlapped WRANs and available bands. Extensive simulation has been conducted to validate our numerical results. [ABSTRACT FROM PUBLISHER]

A number of research groups in various areas of plant biology as well as computer science and applied mathematics have addressed modelling the spatiotemporal dynamics of growth and development of plants. This has resulted in development of functional–structural plant models (FSPMs). In FSPMs, the plant structure is always explicitly represented in terms of a network of elementary units. In this respect, FSPMs are different from more abstract models in which a simplified representation of the plant structure is frequently used (e.g. spatial density of leaves, total biomass, etc.). This key feature makes it possible to build modular models and creates avenues for efficient exchange of model components and experimental data. They are being used to deal with the complex 3-D structure of plants and to simulate growth and development occurring at spatial scales from cells to forest areas, and temporal scales from seconds to decades and many plant generations. The plant types studied also cover a broad spectrum, from algae to trees. This special issue of Annals of Botany features selected papers on FSPM topics such as models of morphological development, models of physical and biological processes, integrated models predicting dynamics of plants and plant communities, modelling platforms, methods for acquiring the 3-D structures of plants using automated measurements, and practical applications for agronomic purposes. [ABSTRACT FROM AUTHOR]

This paper investigates the tracking problem for discrete-time multi-agent systems with a time-varying reference state. The tracking control is designed based on the event-triggered scheme, which can lead to a significant reduction of the information communication burden in the network. To realize the tracking control, only the communication between the agent and its local neighbours is needed, therefore, the designed control is essentially distributed. A numerical example is presented to demonstrate the effectiveness of the theoretical results. [ABSTRACT FROM PUBLISHER]

Nowadays, networks are almost ubiquitous. In the past decade, community detection received an increasing interest as a way to uncover the structure of networks by grouping nodes into communities more densely connected internally than externally. Yet most of the effective methods available do not consider the potential levels of organization, or scales, a network may encompass and are therefore limited. In this paper, we present a method compatible with global and local criteria that enables fast multi-scale community detection on large networks. The method is derived in two algorithms, one for each type of criterion, and implemented with six known criteria. Uncovering communities at various scales is a computationally expensive task. Therefore, this work puts a strong emphasis on the reduction of computational complexity. Some heuristics are introduced for speed-up purposes. Experiments demonstrate the efficiency and accuracy of our method with respect to each algorithm and criterion by testing them against large generated multi-scale networks. This study also offers a comparison between criteria and between the global and local approaches. In particular, our results suggest that global criteria seem to be more robust to noise and thus more accurate than local criteria. [ABSTRACT FROM PUBLISHER]

While multi-label classification can be widely applied for problems where multiple classes can be assigned to an object, its effectiveness may be sacrificed due to curse of dimensionality in the feature space and sparseness of dimensionality in the label space. As a solution, this paper presents two alternative methods, namely Dependent Dual Space Reduction and Independent Dual Space Reduction, to reduce dimensions in the dual spaces, i.e. the feature and label spaces, using singular value decomposition (SVD). The first approach constructs the cross-covariance matrix to represent dependency between the features and labels, projects both of them into a single reduced space, and then performs prediction on the reduced space. On the other hand, the second approach handles the feature space and the label space separately by constructing a covariance matrix for each space to represent feature dependency and label dependency before performing SVD on dependency profile of each space to reduce dimension and for noise elimination and then predicting classes using their reduced dimensions. A number of experiments show that prediction on the reduced spaces for both dependent and independent reduction approaches can obtain better classification accuracy as well as faster computation, compared with the prediction using the original spaces. Finally, the results of our methods are also compared with the prediction using other types of dimensionality reduction, with consideration of the factors of covariance and threshold selection. [ABSTRACT FROM PUBLISHER]

This special issue includes research papers related to a workshop held at the Royal Society on 21st of September 2010, honouring Erol Gelenbe on his 65th birthday. The workshop brought together some 40 participants including some of Erol's former and current PhD students, colleagues and friends with whom he has interacted over the years, both in Europe and the USA. The papers focus on probability models in computer science, at the core of the field of computer performance engineering, which Erol pioneered. [ABSTRACT FROM AUTHOR]

Linkable ring signatures have found many attractive applications. One of the recent important extensions is a linkable threshold ring signature (LTRS) scheme. Unfortunately, the existing LTRS schemes are only secure in the random oracle model (ROM). In this paper, we make the following contributions. First, we construct the first LTRS scheme that is secure without requiring the ROM. Further, we enhance the security of a threshold ring signature (for both linkable or non-linkable) by providing a stronger definition of anonymity. This strengthened notion makes threshold ring signature schemes more suitable in real life. Finally, we provide efficient schemes that outperform the existing schemes in the literature. Our scheme is particularly suitable for electronic commerce or electronic government where anonymity and accountability are the most concerned factors. [ABSTRACT FROM PUBLISHER]

Loiss is a new byte-oriented stream cipher designed in 2010. It takes a 128-bit initial key and a 128-bit initial vector (IV) as inputs, and provides 128-bit-level security claimed by the designers. In this paper, we find a differential characteristic with significant probability over the full initialization of Loiss. Based on this differential characteristic, two differential key recovery attacks on Loiss are proposed. The first attack has a computational complexity of2123.61, requiring two related keys, 234.16 chosen IVs and 239.16 keystream bytes. The second attack is based on the first attack: reducing the computational complexity at the cost of increased data complexity. The second attack has a computational complexity of 264, requiring two related keys, 236.26 chosen IVs and 241.26 keystream bytes. The result shows that our second attack is much better than a brute force attack, and then Loiss does not provide 128-bit-level security. Furthermore, a new proposal for the initialization of Loiss is proposed. The modified Loiss keeps the basic structure of Loiss and provides enough resistance against our attacks on the original Loiss. Based on our security analysis, we conjecture that no attacks lower than brute force are possible on the modified Loiss stream cipher. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents an ethnographic study of mobile communication at a surgical unit in Sweden involved with highly specialized care for the upper abdomen. The primary focus of the study is interruptions related to usage of mobile communication, with the goal of informing the design of systems that better balance interruptions and availability. The department uses a patchwork of hospital pagers, personal cell phones, and department provided cell phones. Issues related to social factors at the department, technical features of mobile communication devices, and specific contexts where interruptions were identified to be a problem are presented. Some of the salient findings of the study include a generally complex situation with respect to interruptions that is impacted by technical, social and individual factors related to mobile communication, challenges related to managing personal and private communication on the same device, issues related to supporting distributed work in highly specialized care and how this contributes to interruptions, and a more in depth overview of specific contexts where interruptions are problematic than previous studies. Some theoretical perspectives on these issues are presented as well as implications for design. [Copyright &y& Elsevier]

Abstract: This paper investigates how users respond to emotional expressions displayed by an embodied agent. In a between-subjects experiment (N =50) an emotionally expressive agent (simulating the role of a nutritional coach) was perceived as significantly more likeable and caring than an unemotional version. Feedback from participants also revealed detailed insights into their perceptions of the agents and highlighted a strong preference for the emotionally expressive version. Design implications for embodied agents are discussed and future research areas identified. [Copyright &y& Elsevier]

Transformations linked to disruptive events are causing a shift in future-oriented technology analysis (FTA) activities from individual large-scale foresight actions to smaller in-house exercises and capacity building. The reasons are manifold relating to the need for an even tighter embedding of FTA in policy-making in a fast-changing complex environment as well as to internal drivers for novel forms of future intelligence to support coordinated and coherent decisions within and across organisations. This paper identifies three ideal types: external FTA services, the institutionalisation of FTA, and FTA networks, whilst recognising that in practice these types are complementary. In empirical terms this requires further investigation, in order to understand how different combinations of activities actually operate in their respective decision-making contexts. It is important to improve our understanding of how far institutionalised FTA can form part of customised solutions for building capacity to handle disruptions. [ABSTRACT FROM AUTHOR]

The Capsule Reviews are intended to provide a short succinct review of each paper in the issue in order to bring it to a wider readership. The Capsule Reviews were compiled by Fairouz Kamareddine. Professor Kamareddine is an Associate Editor of The Computer Journal and is based in the Department of Mathematical and Computer Sciences at Heriot-Watt University, Edinburgh, UK. [ABSTRACT FROM AUTHOR]

There are various ways to measure the shape difference between two n-node rooted binary trees (binary trees for short). A rotation on a binary tree is a local restructuring that changes the tree into another one preserving the in-order sequence. The rotation distance between two binary trees is the minimum number of rotations needed to transform one into another. Till now, no polynomial–time algorithm exists for computing the rotation distance between any two binary trees. Recently, Lucas (Comput. J., 47, 259–269, 2004) presented an O(n2)–time algorithm for finding the rotation distance between two binary trees, where the source tree is a degenerate tree and the destination tree is an angle tree. This paper improves the time-complexity to O(n) under this constraint. [ABSTRACT FROM AUTHOR]

Abstract: For over 40years, system response time has been a topic of interest and controversy in computer science. Since the late 1960s, the field has seen numerous studies conducted and articles written addressing the issue. Many factors were measured in these studies including: users’ accuracy and error rates with different levels of system response time, user performance speed and the efficiency of the commands used, how user interactions with the computer changed as a result of changes in system response time, how their bodies reacted physiologically to those same changes and even how happy, satisfied, anxious or annoyed they were as system response times changed. In this paper, we summarize the major issues in system response time research and look at what can be concluded from them. Generally, researchers have suggested specific response-time guidelines based on the complexity of the task or the type of interaction with the computer. We suggest that rather than system response time being task- or expectation-focused, instead interactions with a computer fall into two categories: control tasks and conversational tasks. For control tasks, immediate response times are necessary for optimal user performance whereas for conversational tasks, some delays may be necessary to maintain the optimal pacing of the on-going conversation. The location and duration of these delays will depend on both task complexity and user expectations. Future system response time research is needed to further quantify limits of delay detection, and the location and duration of inter-task delays to optimize user performance and satisfaction with computers. [Copyright &y& Elsevier]

Composing large enterprise applications from reusable software components has become a major software development technique. Components are considered as black boxes and are composed together by their provided and required services. In comparison to other software development approaches, this allows for rapid development, clean and explicit architectures, and easy component reuse. Currently, there are several systems that support development and composition of components: service component architecture and Fractal are two well-known ones. At first sight, both have the same goals and provide very similar means to developers. In this paper, we briefly present both systems and then we focus on an in-depth comparison and evaluation of them. [ABSTRACT FROM AUTHOR]

This paper presents new algorithms for generating all n-node t-ary trees in linked representation which take constant average time per tree. They use fewer memory references and are considerably faster than previous such algorithms. [ABSTRACT FROM AUTHOR]

Gaussian graphical models explore dependence relationships between random variables, through the estimation of the corresponding inverse covariance matrices. In this paper we develop an estimator for such models appropriate for data from several graphical models that share the same variables and some of the dependence structure. In this setting, estimating a single graphical model would mask the underlying heterogeneity, while estimating separate models for each category does not take advantage of the common structure. We propose a method that jointly estimates the graphical models corresponding to the different categories present in the data, aiming to preserve the common structure, while allowing for differences between the categories. This is achieved through a hierarchical penalty that targets the removal of common zeros in the inverse covariance matrices across categories. We establish the asymptotic consistency and sparsity of the proposed estimator in the high-dimensional case, and illustrate its performance on a number of simulated networks. An application to learning semantic connections between terms from webpages collected from computer science departments is included. [ABSTRACT FROM PUBLISHER]

Applications of modal logics are abundant in computer science, and a large number of structurally different modal logics have been successfully employed in a diverse spectrum of application contexts. Coalgebraic semantics, on the other hand, provides a uniform and encompassing view on the large variety of specific logics used in particular domains. The coalgebraic approach is generic and compositional: tools and techniques simultaneously apply to a large class of application areas and can, moreover, be combined in a modular way. In particular, this facilitates a pick-and-choose approach to domain-specific formalisms, applicable across the entire scope of application areas, leading to generic software tools that are easier to design, to implement and to maintain. This paper substantiates the authors’ firm belief that the systematic exploitation of the coalgebraic nature of modal logic will not only have impact on the field of modal logic itself but also lead to significant progress in a number of areas within computer science, such as knowledge representation and concurrency/mobility. [ABSTRACT FROM AUTHOR]

In this paper we discuss the use of the social concept ‘conviviality’ for computer science in general, and for the development of ambient technologies in particular. First, we give a survey of the use of the concept ‘conviviality’ in the social sciences. Conviviality is usually considered a positive concept related to sociability. However, further analysis reveals a negative side related to lack of diversity, privacy and ethical issues. Second, we argue that conviviality requirements for ambient intelligence are challenging, because ambient technologies give rise to a new virtual and social reality, and conviviality issues play a central role in applications that are concerned with the interaction of material, virtual and social realities. Conviviality highlights an important challenge that we illustrate with examples that emphasize ethical issues, such as privacy threats, surveillance of users and identity theft. Intelligent interfaces, for example, allow instant interactions and thereby create strong needs for coordination and regulation mechanisms that have to be addressed to ensure the safeguard of individuals against abuses, such as privacy intrusions and identity manipulations. Third, we propose a conviviality ontology by operationalizing the fuzzy concept of ‘conviviality,’ such that it can be used in computer science in the same way as other social concepts such as ‘service,’ ‘contract’ or ‘trust’ are used in this area. Conviviality is defined using dependence networks, and tools for conviviality are based on, what we call, conviviality masks. Fourth, we illustrate how convivial ambient intelligence applications can be designed using our operationalized concept of conviviality. We illustrate our arguments and contributions with a running example on the use of ambient technologies in digital cities, as a prototypical example where material reality such as ambient technologies interacts with virtual and social realities. [ABSTRACT FROM PUBLISHER]

This paper studies semantic efficiency measures for ambient intelligence. We follow an agent-based approach and investigate how large quantities of information can be efficiently handled. We will show how to dynamically set up a communication network between agents, which aims to minimize the communication load. The approach is based on a formal ontological notion of informativeness, on quantitative measures such as information gain and on the proper use of interaction mechanisms such as Publish/Subscribe. We also present experimental results that were obtained using our prototyping tool called Ubismart. [ABSTRACT FROM PUBLISHER]

Sensor networks (SNs) consist of spatially distributed sensors which monitor an environment, and which are connected to some sinks or backbone system to which the sensor data is being forwarded. In many cases, the sensor nodes themselves can serve as intermediate nodes for data coming from other nodes, on the way to the sinks. Much of the traffic carried by SNs will originate from routine measurements or observations by sensors that monitor a particular situation, such as the temperature and humidity in a room or the infrared observation of the perimeter of a house, so that the volume of routine traffic resulting from such observations may be quite high. When important and unusual events occur, such as a sudden fire breaking out or the arrival of an intruder, it will be necessary to convey this new information very urgently through the network to a designated set of sink nodes where this information can be processed and dealt with. This paper addresses the important challenge by avoiding the routine background traffic from creating delays or bottlenecks that impede the rapid delivery of high priority traffic resulting from the unusual events. Specifically we propose a novel technique, the ‘Randomized Re-Routing Algorithm (RRR)’, which detects the presence of novel events in a distributed manner, and dynamically disperses the background traffic towards secondary paths in the network, while creating a ‘fast track path’ which provides better delay and better quality of service (QoS) for the high priority traffic which is carrying the new information. When the surge of new information has subsided, this is again detected by the nodes and the nodes progressively revert to best QoS or shortest-path routing for all the ongoing traffic. The proposed technique is evaluated using a mathematical model as well as simulations, and is also compared with a standard node by a node priority scheduling technique. [ABSTRACT FROM PUBLISHER]

As power dissipation causes thermal issues in cooling costs, lifetime and reliability, thermal management has become an important issue in today's OS and processor design. Early OS-level thermal management schemes were proposed and evaluated mainly with simulators or analytical models. In this paper, we implement a thermal-aware round-robin scheduling algorithm in the Linux kernel, and compare its performance with the ‘Heat-and-Run’ algorithm and the default Linux baseline scheduler on an Intel Core 2 Duo processor using representative benchmarks from SPEC2000, MiBench and NetBench. Our results indicate that the current Linux scheduler can easily be enhanced with thermal-awareness to show improved performance in terms of both the on-chip temperature condition and application throughput. [ABSTRACT FROM PUBLISHER]

In this paper, we introduce a new side-channel attack using block cipher cryptanalysis named a meet-in-the-middle attack. Using our new side-channel technique we show that advanced encryption standard (AES) with reduced 10 masked rounds is broken, which is faster than the exhaustive key search attack. This implies that one has to mask the entire rounds of the 12-round 192-bit key AES to prevent our attacks. Our result is the first one to analyse AES with reduced 10 masked rounds, while the previous best known side-channel attack is on AES with reduced eight masked rounds. [ABSTRACT FROM PUBLISHER]

In the design of power-aware on-demand routing protocols in mobile ad hoc networks, it must be taken into account that nodes may use a great amount of power to find the desired routing path during the path-discovery phase. In addition, in previous research on power-aware routing protocols, the path bandwidth was often not considered. In this paper, we tackle these issues by proposing a power-aware routing protocol with low route requests (LRR) to find a path with high path bandwidth. By making a low number of routing requests (RREQs), mobile nodes help to broadcast the routing request only when they first receive the routing requests. In addition, based on the receipt of the routing requests from the neighboring nodes, mobile nodes record the location information of its one-hop neighboring nodes. In the path-reply phase, mobile nodes in the found path use the collected location information of their neighbors and our proposed relay model to modify the found path so that the found path has high bandwidth. In our simulation, we compared our proposed routing protocol (LRR) with ad hoc on-demand distance vector, dynamic source routing and min–max battery capacity routing in terms of the following: power consumption in the path-discovery phase and the path-reply phase, bandwidth of the found path, power consumed during data transmission and overall power consumption. In addition, we compared our two proposed routing protocols, the minimum power consumption routing protocol that selects one path with minimum transmission power from all paths and the LRR routing protocol, in terms of the following: the power consumption in the path-discovery phase, the path bandwidth and the overall power consumption. From the simulation results and the analysis, we can see that the proposed LRR routing protocol that uses a low number of routing requests and our proposed relay model to improve path bandwidth can efficiently reduce the overall power consumption. [ABSTRACT FROM PUBLISHER]