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Presents the special issue in the journal "Parallel Processing Letters," which contains the best papers from the Centre Interantional de Rencontres Mathématiques workshopin October 2001. "Scheduling Issues in Survivality Applications Using Hybrid Fault Models," by A. W. Krings, W. S. Harrison, A. Azadmanesh and M. McQueen"; "Parallel Tabu Search Approaches for Two-Dimensional Cutting," by J. Blazewicz, A. Moret-Salvador and R. Walkowiak"; "Strategies for Workload Balancing in Cluster-Based Image Databases," by F. Drews, K. Ecker, O. Kao and S. Schomann.

Multi-Agent Systems (MAS) have been seen as an attractive area of research for civil engineering professionals to subdivide complex issues. Based on the assignment's history, nearby agents, and objective, the agent intended to take the appropriate action to complete the task. MAS models complex systems, smart grids, and computer networks. MAS has problems with agent coordination, security, and work distribution despite its use. This paper reviews MAS definitions, attributes, applications, issues, and communications. For this reason, MASs have drawn interest from computer science and civil engineering experts to solve complex difficulties by subdividing them into smaller assignments. Agents have individual responsibilities. Each agent selects the best action based on its activity history, interactions with neighbors, and purpose. MAS uses the modeling of complex systems, smart grids, and computer networks. Despite their extensive use, MAS still confronts agent coordination, security, and work distribution challenges. This study examines MAS's definitions, characteristics, applications, issues, communications, and evaluation, as well as the classification of MAS applications and difficulties, plus research references. This paper should be a helpful resource for MAS researchers and practitioners. MAS in controlling smart grids, including energy management, energy marketing, pricing, energy scheduling, reliability, network security, fault handling capability, agent-to-agent communication, SG-electrical cars, SG-building energy systems, and soft grids, have been examined. More than 100 MAS-based smart grid control publications have been reviewed, categorized, and compiled. [ABSTRACT FROM AUTHOR]

The evolution of smart contracts in recent years inspired a crucial question: do smart contract evaluation protocols provide the required level of privacy when executing contracts on the blockchain? The Hawk (IEEE S&P '16) paper introduces a way to solve the problem of privacy in smart contracts by evaluating the contracts off-chain, albeit with the trust assumption of a manager. To avoid the partially trusted manager altogether, a novel approach named zkHawk (IEEE BRAINS '21) explains how we can evaluate the contracts privately off-chain using a multi-party computation (MPC) protocol instead of trusting said manager. This paper dives deeper into the detailed construction of a variant of the zkHawk protocol titled V-zkHawk using formal proofs to construct the said protocol and model its security in the universal composability (UC) framework (FOCS '01). The V-zkHawk protocol discussed here does not support immediate closure, i.e., all the parties (n) have to send a message to inform the blockchain that the contract has been executed with corruption allowed for up to t parties, where t < n . In the most quintessential sense, the V-zkHawk is a variant because the outcome of the protocol is similar (i.e., execution of smart contract via an MPC function evaluation) to zkHawk, but we modify key aspects of the protocol, essentially creating a small trade-off (removing immediate closure) to provide UC (stronger) security. The V-zkHawk protocol leverages joint Schnorr signature schemes, encryption schemes, Non-Interactive Zero-Knowledge Proofs (NIZKs), and commitment schemes with Common Reference String (CRS) assumptions, MPC function evaluations, and assumes the existence of asynchronous, authenticated broadcast channels. We achieve malicious security in a dishonest majority setting in the UC framework. [ABSTRACT FROM AUTHOR]

Distributed computing, computer networking, and the Internet of Things (IoT) are all around us, yet only computer science and engineering majors learn the technologies that enable our modern lives. This paper introduces PhoneIoT, a mobile app that makes it possible to teach some of the basic concepts of distributed computation and networked sensing to novices. PhoneIoT turns mobile phones and tablets into IoT devices and makes it possible to create highly engaging projects through NetsBlox, an open-source block-based programming environment focused on teaching distributed computing at the high school level. PhoneIoT lets NetsBlox programs—running in the browser on the student's computer—access available sensors. Since phones have touchscreens, PhoneIoT also allows building a Graphical User Interface (GUI) remotely from NetsBlox, which can be set to trigger custom code written by the student via NetsBlox's message system. This approach enables students to create quite advanced distributed projects, such as turning their phone into a game controller or tracking their exercise on top of an interactive Google Maps background with just a few blocks of code. [ABSTRACT FROM AUTHOR]

Key-based circuit obfuscation or logic-locking is a technique that can be used to hide the full design of an integrated circuit from an untrusted foundry or end-user. The technique is based on creating ambiguity in the original circuit by inserting "key" input bits into the circuit such that the circuit is unintelligible absent a correct secret key. Clock signals have traditionally been avoided in locking in order to not corrupt the timing behavior of the locked circuit. In this paper, we explore the case where the clock signal itself may be obfuscated by ambiguating its frequency or pattern. Along with discussing formal notions of security in this context, we present practical ways to deobfuscate such designs using techniques from multi-rate model-checking. We present experimental data on deobfuscation runtime on a set of sequential benchmark circuits. Our results show that naive random clock obfuscation may not provide more security per overhead than traditional random keyed-gate insertion. We discuss how clock obfuscation may be a more attractive choice for special circuit designs that are inherently multi-clock/asynchronous. [ABSTRACT FROM AUTHOR]

The Panopticon (which means "watcher of everything") is a well-known prison structure of continuous surveillance and discipline studied by Bentham in 1785. Today, where persistent, massive scale, surveillance is immensely facilitated by new technologies, the term Panopticon vaguely characterizes institutions with a power to acquire and process, undetectably, personal information. In this paper we propose a theoretical framework for studying Panopticons and their detectability status. We show, based on the Theory of Computation, that detecting Panopticons, modelled either as a simple Turing Machine or as an Oracle Turing Machine, is an undecidable problem. Furthermore, we show that for each sufficiently expressive formal system, we can effectively construct a Turing Machine for which it is impossible to prove, within the formal system, its Panopticon status. Finally, we discuss how Panopticons can be physically detected by the heat they dissipate each time they acquire, effortlessly, information in the form of an oracle and we investigate their detectability status with respect to a more powerful computational model than classical Turing Machines, the Infinite Time Turing Machines (ITTMs). [ABSTRACT FROM AUTHOR]

The ever-increasing need for securing computing systems using cryptographic algorithms is spurring interest in the efficient implementation of common algorithms. While the algorithms can be implemented in software using base instruction sets, there is considerable potential to reduce memory cost and improve speed using specialized instructions and associated hardware. However, there is a need to assess the benefits and costs of software implementations and new instructions that implement key cryptographic algorithms in fewer cycles. The primary aim of this paper is to improve the understanding of the performance and cost of implementing cryptographic algorithms for the RISC-V instruction set architecture (ISA) in two cases: software implementations of the algorithms using the rv32i instruction set and using cryptographic instructions supported by dedicated hardware in additional functional units. For both cases, we describe a RISC-V processor with cryptography hardware extensions and hand-optimized RISC-V assembly language implementations of eleven cryptographic algorithms. Compared to implementations with only the rv32i instruction set, implementations with the cryptography set extension provide a 1.5× to 8.6× faster execution speed and 1.2× to 5.8× less program memory for five of the eleven algorithms. Based on our performance analyses, a new instruction is proposed to increase the implementation efficiency of the algorithms. [ABSTRACT FROM AUTHOR]

In today's world, the use of computer networks is everywhere, and to access the home network we use the Internet. IoT networks are the new range of these networks in which we try to connect different home appliances and try to give commands from a remote place. Access to any device over an insecure network invites various types of attacks. User authentication can be performed using some password or biometric technique. However, when it comes to authenticating a device, it becomes challenging to maintain data security over a secure network such as the Internet. Many encryptions and decryption algorithms assert confidentiality, and hash code or message authentication code MAC is used for authentication. Traditional cryptographic security methods are expensive in terms of computational resources such as memory, processing capacity, and power consumption. They are incompatible with the Internet of Things devices that have limited resources. Although automatic Device-to-Device communication enables new potential applications, the limited resources of the networks' machines and devices impose various constraints. This paper proposes a home device authentication scheme when these are accessed from a remote place. An authentication device is used for the home network and controller device to control home appliances. Our scheme can prevent various attacks such as replay attacks, server spoofing, and man-in-the-middle attack. The proposed scheme maintains the confidentiality and authenticity of the user and devices in the network. At the same time, we check the system in a simulated environment, and the results show that the network's performance does not degrade much in terms of delay, throughput, and energy consumed. [ABSTRACT FROM AUTHOR]

In this paper, some types of edge irregular single valued neutrosophic graphs such as neighbourly edge totally irregular single valued neutrosophic graphs, strongly edge irregular single valued neutrosophic graphs and strongly edge totally irregular single valued neutrosophic graphs are introduced. A comparative study between neighbourly edge irregular single valued neutrosophic graphs and neighbourly edge totally ir- regular single valued neutrosophic graphs is done. Likewise some properties of them are studied. Finally, we have given some interesting results about edge irregular single valued neutrosophic graphs that are very useful in computer science and networks. [ABSTRACT FROM AUTHOR]

In this paper, some types of edge irregular single valued neutrosophic graphs such as neighbourly edge totally irregular single valued neutrosophic graphs, strongly edge irregular single valued neutrosophic graphs and strongly edge totally irregular single valued neutrosophic graphs are introduced. A comparative study between neighbourly edge irregular single valued neutrosophic graphs and neighbourly edge totally irregular single valued neutrosophic graphs is done. Likewise some properties of them are studied. Finally, we have given some interesting results about edge irregular single valued neutrosophic graphs that are very useful in computer science and networks. [ABSTRACT FROM AUTHOR]

Digital public displays installed in various locations provide valuable information for the passers-by. However, the static characteristic of the digital public display limits the consumption of the displayed content to a small area. Personal mobile devices such as smartphones are now capable of interacting with digital public displays, which enables the passers-by to “take-away” the content and consume it on-the-go. This process requires device binding, content selection, and transfer between the two devices. In this paper, we propose a device binding method which utilizes the content brightness changing pattern as a unique content ID on the public display and an illuminance sensor on the mobile to bind and transfer between two devices. We conducted performance evaluations for binding algorithm robustness in different conditions. Also comparative studies among other binding interaction methods were conducted. Our results show that our proposed method performed stably across the various conditions and overall performance in interaction completion time and error rate was similar or superior to the existing methods. [ABSTRACT FROM AUTHOR]

Certificateless aggregate signature (CLAS) is a crucial cryptosystem. It can not only compress multiple signatures into a short signature, but also ensure the validity of each signature participating in the aggregation by verifying the validity of an resulting aggregate signature. Therefore, a secure and efficient CLAS scheme is very useful for resource-constrained environments because it greatly reduces the overall length of the signature and the verifier’s computational overhead. Cheng et al. presented an efficient CLAS scheme and proved its security in the random oracle model. However, we find that their scheme has security flaws. In this paper, we demonstrate that Cheng et al.’s CLAS scheme is vulnerable to coalition attacks from internal signers. To overcome these attacks, we present an improved CLAS scheme and prove that it is existentially unforgeable under the computational Diffie-Hellman assumption. In addition, our CLAS scheme can not only resist coalition attacks but also generate a very short aggregate signature. The performance analysis results show that our improved CLAS scheme is lower than the related CLAS schemes in terms of communication overhead and computation cost. [ABSTRACT FROM AUTHOR]

The accuracy and diversity of recommendation algorithms have always been the research hotspot of recommender systems. A good recommender system should not only have high accuracy and diversity, but also have adequate robustness against spammer attacks. However, the issue of recommendation robustness has received relatively little attention in the literature. In this paper, we systematically study the influences of different spammer behaviors on the recommendation results in various recommendation algorithms. We further propose an improved algorithm by incorporating the inner-similarity of user’s purchased items in the classic KNN approach. The new algorithm effectively enhances the robustness against spammer attacks and thus outperforms traditional algorithms in recommendation accuracy and diversity when spammers exist in the online commercial systems. [ABSTRACT FROM AUTHOR]

This paper describes an approach for improving the accuracy of memory-based collaborative filtering, based on the technique for order of preference by similarity to ideal solution (TOPSIS) method. Recommender systems are used to filter the huge amount of data available online based on user-defined preferences. Collaborative filtering (CF) is a commonly used recommendation approach that generates recommendations based on correlations among user preferences. Although several enhancements have increased the accuracy of memory-based CF through the development of improved similarity measures for finding successful neighbors, there has been less investigation into prediction score methods, in which rating/preference scores are assigned to items that have not yet been selected by a user. A TOPSIS solution for evaluating multiple alternatives based on more than one criterion is proposed as an alternative to prediction score methods for evaluating and ranking items based on the results from similar users. The recommendation accuracy of the proposed TOPSIS technique is evaluated by applying it to various common CF baseline methods, which are then used to analyze the MovieLens 100K and 1M benchmark datasets. The results show that CF based on the TOPSIS method is more accurate than baseline CF methods across a number of common evaluation metrics. [ABSTRACT FROM AUTHOR]

This paper presents a model for semantic network representation. According to the model, the main purpose of a semantic network is to help to correctly and quickly understand the features and structure of the solutions, and then make reliable predictions about their outcomes and rewards. These objectives are achieved under constrains like limited resources (e.g., memory size and access), time limitations, and variations of solution characteristics. The paper summarizes the elements of the model and presents a set of properties that describe the effectiveness of semantic networks in creative problem solving, including design. Six examples (based on three case studies from the related literature and three experimental studies conducted by the authors) discuss the model elements, characteristics, and properties. [ABSTRACT FROM AUTHOR]

Advanced Metering Infrastructure (AMI) realizes a two-way communication of electricity data through by interconnecting with a computer network as the core component of the smart grid. Meanwhile, it brings many new security threats and the traditional intrusion detection method can’t satisfy the security requirements of AMI. In this paper, an intrusion detection system based on Online Sequence Extreme Learning Machine (OS-ELM) is established, which is used to detecting the attack in AMI and carrying out the comparative analysis with other algorithms. Simulation results show that, compared with other intrusion detection methods, intrusion detection method based on OS-ELM is more superior in detection speed and accuracy. [ABSTRACT FROM AUTHOR]

The vast variety of applications available and being developed for computer networks have different quality of service requirements. One of the most significant ways to satisfy the needs of the applications is the packet scheduling algorithms employed by the network routers. By allocating router resources to the applications, packet schedulers try to improve the quality of service needs of the applications. Thus, the delays can be reduced or the reliability of the applications can be increased by reducing packet losses. Priority schedulers are able reduce the delay and losses for high priority applications. On the other hand, for low priority applications they introduce the starvation problem. Low priority application packets can face excessive delays and losses. In this paper, a non-preemptive priority scheduler with multiple thresholds (PRMT) is proposed. The PRMT scheduler needs only a single queue with predefined threshold levels for different priority applications. The PRMT scheduler eliminates the starvation problem of low priority applications without a significant impact on the high priority applications. [ABSTRACT FROM AUTHOR]

Community structure is one of the most important and basic topologic properties of complex network. The rational division of community structure in complex network is the main purpose of the complex network's community division research. This paper mainly researched the division of community structure in complex network based on the theory of supernetwork and standardized degree centrality. Based on the lack of GN algorithm, this paper proposed a new comprehensive algorithm to divide community structure from the perspective of supernetwork. Finally, the new comprehensive algorithm is illustrated through examples. [ABSTRACT FROM AUTHOR]

Aim at the problem for how to analyze the propensity to spread of shortage of supplies in emergency logistics decision support system, this paper proposed a new model to study the propensity to spread of shortage of supplies for emergency logistics network. This paper, by the mechanism of viral spreading and introducing the parameter of time "t", it constructed SI-SIRS ( susceptible infective and susceptible infective recover susceptible) model to analyze the scale-free network which included 61 nodes. Case analysis shows that SIRS effectively depicts the spread behavior of shortage of supplies in emergency logistics network. Propensities to spread of shortage of supplies are effected by node self-spread ability, network topology, individual nodes differences and responding mechanism of emergency logistics. [ABSTRACT FROM AUTHOR]

Abstract: The Data Grid provides massive aggregated computing resources and distributed storage space to deal with data-intensive applications. Due to the limitation of available resources in the grid as well as production of large volumes of data, efficient use of the Grid resources becomes an important challenge. Data replication is a key optimization technique for reducing access latency and managing large data by storing data in a wise manner. Effective scheduling in the Grid can reduce the amount of data transferred among nodes by submitting a job to a node where most of the requested data files are available. In this paper two strategies are proposed, first a novel job scheduling strategy called Weighted Scheduling Strategy (WSS) that uses hierarchical scheduling to reduce the search time for an appropriate computing node. It considers the number of jobs waiting in a queue, the location of the required data for the job and the computing capacity of the sites Second, a dynamic data replication strategy, called Enhanced Dynamic Hierarchical Replication (EDHR) that improves file access time. This strategy is an enhanced version of the Dynamic Hierarchical Replication strategy. It uses an economic model for file deletion when there is not enough space for the replica. The economic model is based on the future value of a data file. Best replica placement plays an important role for obtaining maximum benefit from replication as well as reducing storage cost and mean job execution time. So, it is considered in this paper. The proposed strategies are implemented by OptorSim, the European Data Grid simulator. Experiment results show that the proposed strategies achieve better performance by minimizing the data access time and avoiding unnecessary replication. [Copyright &y& Elsevier]

Convolutional neural network (CNN) has achieved the state-of-the-art performance in many different visual tasks. Learned from a large-scale training data set, CNN features are much more discriminative and accurate than the handcrafted features. Moreover, CNN features are also transferable among different domains. On the other hand, traditional dictionary-based features (such as BoW and spatial pyramid matching) contain much more local discriminative and structural information, which is implicitly embedded in the images. To further improve the performance, in this paper, we propose to combine CNN with dictionary-based models for scene recognition and visual domain adaptation (DA). Specifically, based on the well-tuned CNN models (e.g., AlexNet and VGG Net), two dictionary-based representations are further constructed, namely, mid-level local representation (MLR) and convolutional Fisher vector (CFV) representation. In MLR, an efficient two-stage clustering method, i.e., weighted spatial and feature space spectral clustering on the parts of a single image followed by clustering all representative parts of all images, is used to generate a class-mixture or a class-specific part dictionary. After that, the part dictionary is used to operate with the multiscale image inputs for generating mid-level representation. In CFV, a multiscale and scale-proportional Gaussian mixture model training strategy is utilized to generate Fisher vectors based on the last convolutional layer of CNN. By integrating the complementary information of MLR, CFV, and the CNN features of the fully connected layer, the state-of-the-art performance can be achieved on scene recognition and DA problems. An interested finding is that our proposed hybrid representation (from VGG net trained on ImageNet) is also complementary to GoogLeNet and/or VGG-11 (trained on Place205) greatly. [ABSTRACT FROM AUTHOR]

Many real-world networks have a topological structure characterized by cohesive groups of vertices. To perform the task of identifying such subsets of vertices, community detection in networks has aroused the interest of researchers and practitioners alike. In spite of the existence of various efficient community detection algorithms in the literature, most of them uses global information about the network, not applicable to distributed networks. This paper proposes a genetic-based algorithm to detect communities in directed networks based on local information to generate the offspring. The major difference between the proposed strategy and those found in the literature is the way of exploiting target regions of interest in the solution space. This step is directly influenced by the crossover operator that depends largely on the individual representation. In the introduced strategy, GA-LP, the individual is locally stored in the vertices as labels, what brings more flexibility in the system to be adapted to address applications that involve, for example, dynamic networks. In computational experiments, the proposed strategy showed an outstanding performance, being fast, achieving the best results on average in the networks tested. [ABSTRACT FROM AUTHOR]

In wireless ad hoc networks, maintaining network connectivity is very important as high level network functions all depend on it. However, how to measure network connectivity remains a fundamental challenge. For example, a network can have good overall k -connectivity and yet still have a communication bottleneck. In this paper, we address how to locate bottlenecks and relieve them. A new connectivity measure based on the Cheeger's Constant is used for bottleneck discovery, and a partition algorithm that divides the network at the bottleneck is developed. After the network is partitioned, we consider deploying a relay node to increase the conductance of the network across the partition. The relay node deployment problem is formulated as an integer linear program to maximize the number of connections between the two sides of the cut, and then a convex optimization algorithm is used to find the precise location of the relay node, which is within the convex hull defined by the radio transmission ranges of all the nodes that can connect to the relay node. We show that the relay node significantly relieves the bottleneck and improves network connectivity, which is manifested by several network connectivity metrics. The partition and relay node deployment algorithms are then extended to the case where multiple relay nodes are available. Multiway partition and multiple relay node deployment algorithms are presented. Simulation results show this approach effectively enhances network connectivity with a small number of relay nodes. [ABSTRACT FROM AUTHOR]

The conditional diagnosability of many well-known networks has been explored. In this paper, we analyze the conditional diagnosability of a family of networks, called the round matching composition networks, which are a class of networks composed of r ( r ≥ 4 ) components of the same order linked by r perfect matchings. Applying the result, we determine the conditional diagnosability of the k -ary n -cubes and the recursive circulant graphs under the PMC model and the MM model, respectively. [ABSTRACT FROM AUTHOR]

Visibly Pushdown Automata ( VPA ) are a special case of pushdown machines where the stack operations are driven by the input. In this paper, we consider VPA with multiple stacks , namely n-VPA , with n > 1 . These automata introduce a useful model to effectively describe concurrent pushdown systems using a simple communication mechanism between stacks. We show that n -VPA are strictly more expressive than VPA. Indeed, n -VPA accept some context-sensitive languages that are not context-free and some context-free languages that are not accepted by any VPA. Nevertheless, we show that the class of languages accepted by n -VPA is closed under union and intersection. On the contrary, this class turns out to be neither closed under complementation nor determinizable. Moreover, we show that the emptiness problem for n -VPA is undecidable. By adding an ordering constraint on stacks ( n -OVPA), decidability of emptiness can be recovered, as well as the closure under complementation. Using these properties along with the automata-theoretic approach, one can prove that the model checking problem over n -OVPA models against n -OVPA specifications is decidable. [ABSTRACT FROM AUTHOR]

Asynchronously communicating systems involve peers or entities that communicate by exchanging messages via buffers. In general, the size of such buffers is not known apriori, i.e., they are considered to be unbounded. As a result, models of asynchronously communicating systems typically exhibit infinite state spaces and it is well-known that reachability and boundedness problems for such models are undecidable. This, in turn, makes automatic verification of asynchronous systems undecidable as well. We discuss a particular class of asynchronous systems over peers for which the interaction behaviors do not change when the peers are made to communicate synchronously. Such systems are referred to as Synchronizable . Automatic verification of synchronizable systems is decidable as the verification of the system can be performed using its synchronous counterpart. Recently, we have proved that checking whether or not a system is synchronizable is decidable. In this paper, we consider different types of asynchronous communication, where the type is described in terms of the nature of buffering and the number of buffers, and discuss how/if synchronizability is decidable for each type. The new results subsume the existing ones and present a comprehensive synchronizability study of asynchronous systems. [ABSTRACT FROM AUTHOR]

Application layer firewalls protect the trusted area network against information security risks. However, firewall performance may affect user experience. Therefore, performance analysis plays a significant role in the evaluation of application layer firewalls. This paper presents an analytic model of the application layer firewall, based on a system analysis to evaluate the capability of the firewall. In order to enable users to improve the performance of the application layer firewall with limited resources, resource allocation was evaluated to obtain the optimal resource allocation scheme in terms of throughput, delay, and packet loss rate. The proposed model employs the Erlangian queuing model to analyze the performance parameters of the system with regard to the three layers (network, transport, and application layers). Then, the analysis results of all the layers are combined to obtain the overall system performance indicators. A discrete event simulation method was used to evaluate the proposed model. Finally, limited service desk resources were allocated to obtain the values of the performance indicators under different resource allocation scenarios in order to determine the optimal allocation scheme. Under limited resource allocation, this scheme enables users to maximize the performance of the application layer firewall. [ABSTRACT FROM AUTHOR]

Community detection is an important task for uncovering underlying structures and analyzing group behavior in complex networks. A fuzzy community detection method is proposed in this paper to detect fuzzy community structures without any prior knowledge. Compared with previous studies, we introduce a structural similarity to measure fuzzy relation between vertices based on local interactions between neighboring vertices. In our method, we take the fuzzy similarity between vertices and fuzzy transitivity of the similarity in network topology into consideration. Moreover, multiresolution community structures can be detected by varying the fuzzy threshold. Experimental results and comparisons with some state-of-the-art methods are presented on a variety of benchmark graphs. It shows that the method is efficient in detecting communities on both real-world and synthetic networks. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents an approach for designing a language for network description, leading to a Network Node Description Language (NNDL). NNDL is generic and platform independent XML based language designed to describe a complete configuration of each network node. The node description in NNDL has all necessary information for the nodes configurations, from the common IPv4 and IPv6 addressing, firewall settings, static and dynamic routing to the complete description of the network services configuration. It provides the basis for description of a wide range of virtual network laboratory scenarios. The language has been tested in a virtual network laboratory VNLab used in a university networking course. With the introduction of NNDL language, VNLab environment becomes more flexible in terms of number of available scenarios and the time needed to create and modify them. Some extensions of NNDL for documenting computer networks are also explored in this paper. [Copyright &y& Elsevier]

Abstract: Mobile communication has become the major choice of personal communication today. With the rapid proliferation of wireless network technologies, mobile users can communicate through more and more different wireless networks. In such a heterogeneous wireless network environment, traditional wisdom is to ensure mobile users always best connected (ABC) to one of their nearby available networks. However, the ABC strategy may be sub-optimal as the cost and quality of multimedia communication depends not only on the access network of the caller (source) but also on that of the callee (destination). Thus, intelligently selecting a best network connection, or a source and destination access network pair, for users is necessary in next generation multimedia communication, in which various media types, such as voice, video and data, are related and jointly contribute to the communication quality and cost. This paper utilized Analytic Network Process (ANP) to model the problem of call setup strategy for multimedia communication. ANP is powerful in representing complex networked decision process. In the paper, we illustrated, by an example, how ANP sets up calls that fulfill the requirement of users. [Copyright &y& Elsevier]

Abstract: This paper is the second part of a series of two papers dealing with bulking: a way to define quasi-order on cellular automata by comparing space-time diagrams up to rescaling. In the present paper, we introduce three notions of simulation between cellular automata and study the quasi-order structures induced by these simulation relations on the whole set of cellular automata. Various aspects of these quasi-orders are considered (induced equivalence relations, maximum elements, induced orders, etc.) providing several formal tools allowing to classify cellular automata. [Copyright &y& Elsevier]

The idea behind cloud computing is to deliver Infrastructure-, Platform- and Software-as-a-Service (IaaS, PaaS and SaaS) over the Internet on an easy pay-per-use business model. The Hochschule Furtwangen University (HFU) is running their own private cloud infrastructure, called Cloud Infrastructure and Application CloudIA. The targeted users of the CloudIA project are HFU staff and students running e-Learning applications, and external people for collaboration purposes. Therefore, in this paper, we introduce our work in building a private cloud. More specifically, this paper shows how our cloud offerings in each of the cloud service models, i.e. IaaS, PaaS and SaaS, address the requirements and needs of e-Learning and collaboration in an university environment. [ABSTRACT FROM AUTHOR]

In this paper, a dynamic wavelet network (DWN) is proposed and applied to identify black box models of the process. The well-known delta-rule is extended to the dynamic delta-rule in order to optimize wavelet network parameters. A chemical process was chosen as a realistic nonlinear system to demonstrate the identification performance. A comparison was made between the approach presented in this paper and dynamic multi layer perceptron neural networks. [ABSTRACT FROM AUTHOR]

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]

The Internet contains thousands of Frequently Updated, Time-stamped, Structured (FUTS) data sources. This type of information represents a different class of information that is not properly handled by existing data management systems such as databases, data warehouses, search engines, pub-sub, event processing or information retrieval systems. In this position paper, we describe 9ticks, a system we are designing to collect, parse, store, query and disseminate FUTS information. 9ticks is helping us understand that all those steps raise new challenges but also bring new opportunities. In this paper, we summarize the challenges identified and present our vision of an end-to-end FUTS management system. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a testability enhancement technique suited for AND–EXOR based logic networks that facilitates easy detection of stuck-at and bridging faults by a universal test set. Both cascaded and tree implementations of the EXOR-part are considered. The AND–EXOR based circuit implemented with a cascaded EXOR-part requires a universal test set of size (2n +6) for an n-variable function implementation. For Generalized Reed–Muller (GRM) implementation, this test set detects all single stuck-at and bridging faults (both OR-type and AND-type) and also large number of multiple bridging faults. For an Exclusive-OR Sum-of-Products (ESOP) implementation, a few single bridging faults may remain untested under this test set, occurrence of which can be minimized by employing an appropriate design and layout technique. Next, it is shown that an AND–EXOR network with a tree-based EXOR-part can be tested for similar faults by a universal test set of size (2n +8). This paper also solves an open problem of designing a universal test for a tree-based AND–EXOR circuit. Since the EXOR-tree has depth of (), where s is the number of product terms in the given AND–EXOR expression, this tree-based design reduces the circuit delay significantly compared to cascaded EXOR implementation. In both the cases, the test set can be stored in a ROM on-chip for built-in self-test (BIST) purposes. For several benchmark circuits, the universal test set is found to be much smaller in size than the ATPG-generated test sets. [Copyright &y& Elsevier]

Abstract: Reliable transmission is a key issue for distributed real-time applications. The concept of Real-time Dependable Channel was introduced to provide availability to real-time transmission. Two aspects are important for the efficiency of a Real-time dependable channel: assuring the end-to-end delay bound and optimising the utilisation of network resources. A packet can miss its delay bound for two reasons: network congestion or network failure. The classic solution to this problem has been the use of Backup Channels which introduces the notion of availability at the expense of increasing the use of network resources. However, this over-provisioning of resources is potentially wasted, since the failure rate is very low. This paper introduces a new failure detection scheme for Real-time Transmission, which is called Proactive Backup Channel. This scheme is based on activating the backup channel before a network failure or congestion is produced. This way, the failure recovery time is reduced, and, as proven in the paper, the use of network resources is minimized. [Copyright &y& Elsevier]

This paper introduces, at a high level, the key topics relevant to continuous availability of IBM systems infrastructures. After defining terms and identifying what is encompassed in the scope of continuous availability of IBM system infrastructures, we explain the IT (information technology) life cycle of planning and execution through which an IT organization and its infrastructure pass to create and continuously improve the IT infrastructure. Throughout, we show how each of the subsequent papers in this issue, drawing on real-life deployments, technology developments, and research efforts, expands on important aspects of this introductory discussion. [ABSTRACT FROM AUTHOR]

Efficient exact schedulability tests are required both for online admission of applications to dynamic systems and as an integral part of design tools for complex distributed real-time systems. This paper addresses performance issues with exact response time analysis (RTA) for fixed priority preemptive systems. Initial values are introduced that improve the efficiency of the standard RTA algorithm 1) when exact response times are required and 2) when only exact schedulability need be determined. This paper also explores modifications to the standard RTA algorithm, including the use of a response time upper bound to determine when exact analysis is needed, incremental computation aimed at faster convergence, and checking tasks in reverse priority order to identify unschedulable tasksets early. The various initial values and algorithm implementations are compared by means of experiments on a PC recording the number of iterations required and execution time measurements on a real-time embedded microprocessor. Recommendations are provided for engineers tasked with the problem of implementing exact schedulability tests as part of online acceptance tests and spare capacity allocation algorithms or as part of offline system design tools. [ABSTRACT FROM AUTHOR]

Emerging network technologies have complex network interfaces that have renewed concerns about network reliability. In this paper, we present an effective low-overhead fault tolerance technique to recover from network interface failures. Failure detection is based on a software watchdog timer that detects network processor hangs and a self-testing scheme that detects interface failures other than processor hangs. The proposed self-testing scheme achieves failure detection by periodically directing the control flow to go through only active software modules in order to detect errors that affect instructions in the local memory of the network interface. Our failure recovery is achieved by restoring the state of the network interface using a small backup copy containing just the right amount of information required for complete recovery. The paper shows how this technique can be made to minimize the performance impact to the host system and be completely transparent to the user. [ABSTRACT FROM AUTHOR]

Abstract: This paper addresses the question why standard-compliant IT products often do not interoperate. The findings are based on an institutional analysis, three case studies, and a debate among experts. The paper concludes that some dilemmas cannot be resolved easily. However, many causes can be addressed, in particular those in the area of standard development. Where interoperability is concerned, standard development and implementation issues cannot be meaningfully separated. [Copyright &y& Elsevier]

Understanding how to implement software process improvement (SRI) successfully is arguably the most challenging issue facing the SPI field today. The SPI literature contains many case studies of successful companies and descriptions of their SRI programs. However, the research efforts to date are limited and inconclusive and without adequate theoretical and psychometric justification. This paper extends and integrates models from prior research by performing an empirical investigation of the key factors for success in SPI. A quantitative survey of 120 software organizations was designed to test the conceptual model and hypotheses of the study. The results indicate that success depends critically on six organizational factors, which explained more than 50 percent of the variance in the outcome variable. The main contribution of the paper is to increase the understanding of the influence of organizational issues by empirically showing that they are at least as important as technology for succeeding with SPI and, thus, to provide researchers and practitioners with important new insights regarding the critical factors of success in SPI. [ABSTRACT FROM AUTHOR]

This paper presents a methodological approach based on Bayesian Networks for modelling the behaviour of the students of a bachelor course in computers in an Open University that deploys distance educational methods. It describes the structure of the model, its application for modelling the behaviour of student groups in the Informatics Course of the Hellenic Open University, as well as the advantages of the presented method under conditions of uncertainty. The application of this model resulted in promising results as regards both prediction of student behaviour, based on modelled past experience, and assessment (i.e., identification of the reasons that led students to a given `current'' state). The method presented in this paper offers an effective way to model past experience, which can significantly aid in decision-making regarding the educational procedure. It can also be used for assessment purposes regarding a current state enabling tutors to identify mistakes or bad practices so as to avoid them in the future as well as identify successful practices that are worth repeating. The paper concludes that modelling is feasible and that the presented method is useful especially in cases of large amounts of data that are hard to draw conclusions from without any modelling. It is emphasised that the presented method does not make any predictions and assessments by itself; it is a valuable tool for modelling the educational experience of its user and exploiting the past data or data resulting from its use. [Copyright &y& Elsevier]

We carry forward the work described in our previous papers [5,18,20] on the application of data independence to the model checking of security protocols using CSP [19] and FDR [10]. In particular, we showed how techniques based on data independence [12,19] could be used to justify, by means of a finite FDR check, systems where agents can perform an unbounded number of protocol runs. Whilst this allows for a more complete analysis, there was one significant incompleteness in the results we obtained: while each individual identity could perform an unlimited number of protocol runs sequentially, the degree of parallelism remained bounded (and small to avoid state space explosion). In this paper, we report significant progress towards the solution of this problem, by means anticipated in [5], namely by “internalising” protocol roles within the “intruder” process. The internalisation of protocol roles (initially only server‐type roles) was introduced in [20] as a state‐space reduction technique (for which it is usually spectacularly successful). It was quickly noticed that this had the beneficial side‐effect of making the internalised server arbitrarily parallel, at least in cases where it did not generate any new values of data independent type. We now consider the case where internal roles do introduce fresh values and address the issue of capturing their state of mind (for the purposes of analysis). [ABSTRACT FROM AUTHOR]

In this paper, we focus on convergence packet routing techniques in an all-optical network, obtained from an Eulerian routing in the digraph modeling the target network. Given an Eulerian circuit C in a digraph C, we deal with the maximal number diamWC of arcs that a packet has to follow on C from its origin to its destination (we talk about the ending guarantee of the routing). We consider the Eulerian diameter of C as defined by E(C) = mm C ∈ Eul(G) diamWc, where E(G) is the set of all the Eulerian circuits in C. After giving a preliminary result about the complexity of finding ((C) for any digraph G, we give some lower and upper bounds of this parameter. The main part of the paper is devoted to the description of a combinatorial design of various network topologies having good Eulerian diameters. [ABSTRACT FROM AUTHOR]

We discuss nearest neighbor load balancing schemes on processor networks which are represented by a cartesian product of graphs and present a new optimal diffusion scheme for general graphs. In the first part of the paper, we introduce the Alternating-Direction load balancing scheme, which reduces the number of load balance iterations by a factor of 2 for cartesian products of graphs. The resulting flow is theoretically analyzed and can be very high for certain cases. Therefore, we further present the Mixed-Direction scheme which needs the same number of iterations but computes in most cases a much smaller flow. In the second part of the paper, we present a simple optimal diffusion scheme for general graphs, calculating a balancing flow which is minimal in the l2 norm. It is based on the spectra of the graph representing the network and needs only m — 1 iterations to balance the load with m being the number of distinct eigenvalues. Known optimal diffusion schemes have the same performance, however the optimal scheme presented in this paper can be implemented in a very simple manner. The number of iterations of optimal diffusion schemes is independent of the load scenario and, thus, they are practical for networks which represent graphs with known spectra. Finally, our experiments exhibit that the new optimal scheme can successfully be combined with the Alternating-Direction and Mixed-Direction schemes for efficient load balancing on product graphs. [ABSTRACT FROM AUTHOR]

This paper investigates the idea of organization transformation appropriate to the advent of information technologies (IT). Specifically, we describe a traceable framework of transformation, which accommodates the shift of information system (IS) support from automating to informating to knowledging. The paper intends to clarify the context of IT/IS-based organization transformation through the contextualization of IS support and its relation to organizational design. This is done by elaborating the design issue of IS support that help structure and facilitate knowledge interconnectivity, through the exposition of the social processes in which, in a specific organizational context, a particular group of people can conceptualize their world and hence the purposeful action they wish to undertake. That provides the basis for ascertaining what information support is needed by those who undertake that action. Only then does it become appropriate to ask how modern IT can help to provide that support. We conclude by reiterating the challenge of designing IS's as meaning attribution systems in which people select certain resources out of the mass potentially available and get them processed by means of IT, to make them meaningful in order to support their purposeful actions. [ABSTRACT FROM AUTHOR]

Failed Information Technology (IT) projects are common in organisations, as IT solutions often do not meet the expectations of business clients. Business experts often have a negative perception of the people working in the IT function. There seems to be a proverbial "chicken-and-egg situation": the relationship between business and IT suffers because IT projects fail to solve the real business need and, on the other hand, many IT projects fail because of existing interpersonal relationship problems between business- and IT employees. Research was done to identify categories of issues in the business-IT interface and rank them in order of significance. The term "fusion" is used in this paper, to refer to the process by which the elements of the IT function and the rest of the business work together to achieve a common goal. This paper reports on the categories of issues and draws a conclusion of what would constitute fusion in the business-IT interface. [ABSTRACT FROM AUTHOR]

With the emergence of networked data, graph classification has received considerable interest during the past years. Most approaches to graph classification focus on designing effective kernels to compute similarities for static graphs. However, they become computationally intractable in terms of time and space when a graph is presented in an incremental fashion with continuous updates, i.e., insertions of nodes and edges. In this paper, we examine the problem of classification in large-scale and incrementally changing graphs. We propose a framework combining an incremental support vector machine (SVM) with theWeisfeiler-Lehman (W-L) graph kernel. By retaining the support vectors from each learning step, the classification model is incrementally updated whenever new changes are made to the graph. We design an entropy-based subgraph extraction strategy, that selects informative neighbor nodes and discards those with less discriminative power, to facilitate the classification of nodes in a dynamic network. We validate the advantages of our learning techniques by conducting an empirical evaluation on several large-scale real-world graph datasets in comparison with other graph classification methods. The experimental results also validate the benefits of our subgraph extraction method when combined with the incremental learning techniques. [ABSTRACT FROM AUTHOR]

In network on chips (NoCs) design, reconfiguration of NoC is a very effective option for minimizing power consumption, and Gaussian networks can provide significant advantage over the mesh networks in terms of network diameter, average hop distance and so on. In this paper, based on the special topology structure and the static connection rules within Gaussian networks, we present the reconfiguration representation for Gaussian networks and the nature of reconfigurable Gaussian networks. Furthermore, reconfigurable rules of Gaussian networks are proposed to design the constraints for automatic reconfiguration of NoC. [ABSTRACT FROM PUBLISHER]