The Computer Journal - recent issues

Increasing Service Availability in a Wireless Home Network Environment

Lin, C.-Y., Wang, S.-C., Kuo, S.-Y., Chen, C.-Y. — Fri, 20 Nov 2009 08:02:32 PST

Service-oriented architecture (SOA) paradigm is an inspiring and evolving concept in the context of IT and business services. Recently, various networked embedded systems are penetrating into our life; the unique characteristics of these systems pose many technological challenges. Specifically, the capabilities to interoperate across home appliances and personal digital devices are critical in a smart home environment. As a consequence, the SOA paradigm is introduced as a basis to enhance the service interoperability. However, the service availability is another important concern. In this paper, we focus on augmenting the smart home environment with high service availability. First, we point out the potential problems by adopting the universal plug and play (UPnP) quality of service (QoS) architecture to deliver services with QoS requirements in wireless home networks. After that, we propose a local detour mechanism to tolerate link congestions and node/link failures. Furthermore, the proposed mechanism is based on standard UPnP actions, so that modifications to the existing UPnP QoS architecture are not required. Compared with content-adaptive and resource-adaptive-based approaches operated on fixed service routing paths, our work not only guarantees content quality, but also tolerates topology changes in wireless home networks.

SH-CRBAC: Integrating Attribute and Status Constraints into the RBAC Model in Smart Home Systems

Zou, D., Park, J. H., Kim, T.-H., Chen, X. — Fri, 20 Nov 2009 08:02:32 PST

The requirements for access control have been increased significantly in smart home systems. Many factors such as user ID, user location, service usage conditions and so on, regarded as authorization attributes, are important in making authorization decision in smart home systems. We investigate into the dynamic characteristics of the authorization in smart home systems and propose a new access-control model, SH-CRBAC, which aims to combine the advantages of attribute-based authorization mechanism and role-based access-control mechanism, and imposes attribute and status constraints on the RBAC model and enhances the generality and flexibility of authorization significantly in smart home systems. The status consistency of SH-CRBAC is analysed, and we also analyse the characteristics of SH-CRBAC through comparison with other popular existing authorization models in smart home systems.

Home Network Device Authentication: Device Authentication Framework and Device Certificate Profile

Lee, Y.-K., Lee, D. G., Han, J.-W., Kim, T.-H. — Fri, 20 Nov 2009 08:02:32 PST

As home devices have various functions and have improved computing power and networking ability, home device authentication has become increasingly important for improving the security of home network users. Moreover, device authentication supplies user convenience for the home network service user because it can replace the user authentication required for the used home network service. In addition, the safety of the home network can be strengthened if device authentication is considered in addition to the authentication and access control for the home network user. In this paper, we describe home device authentication, which is a basic and essential element of home network security. We propose a home device authentication framework, home device registration, method of issuing certificates and a home device certificate profile. Our home device certificate profile is based on the Internet X.509 certificate. In short, our device authentication concept can offer convenience and security to users of a home network service.

Near-Optimal Tracking for Residents' Comfort in Context-Aware Heterogeneous Smart Environments

Saxena, N., Roy, A., Shin, J. — Fri, 20 Nov 2009 08:02:32 PST

An information-theoretic, optimal framework is developed for tracking the residents in a context-aware heterogeneous smart environment. The framework envisions that each individual sensor system operates fairly independently and does not require public knowledge of individual topologies. The resident-tracking problem is formulated in terms of a new concept of weighted entropy. The framework is truly universal and provides an optimal, online learning and prediction of inhabitant's movement (location) profiles from the symbolic domain. The overall optimal tracking in heterogeneous smart homes is proved to be an NP-complete problem, and a greedy heuristic for near-optimal tracking is proposed. The concept of asymptotic equipartition property is also explored to predict the inhabitant's most likely path segments (comprising coverage areas of different sensor systems) with very good accuracy. Successful prediction helps in on-demand operations of automated indoor devices along the inhabitant's future paths and locations, thus providing the necessary comfort at a near-optimal cost. Simulation results on a typical smart home corroborate a high prediction success of ~91%, thereby providing sufficient resident-comfort (≥7 in the scale of 10) while reducing the daily energy consumption and manual operations to less than one-third of its original values.

GA-Based Keyword Selection for the Design of an Intelligent Web Document Search System

Chou, C.-H., Lee, C.-H., Chen, Y.-H. — Fri, 20 Nov 2009 08:02:32 PST

The main steps for designing an automatic document classification system include feature extraction and classification. In this article a method to improve feature extraction is proposed. In this method, genetic algorithm was applied to determine the threshold values of four criteria for extracting the representative keywords for each class. The purpose of these four threshold values is to extract as few representative keywords as possible. This keyword extraction method was combined with two classification algorithms, vector space model and support vector machine, for examining the performance of the proposed classification system under various extracting conditions.

An Improved RFID-Based Locating Algorithm by Eliminating Diversity of Active Tags for Indoor Environment

Zhang, T., Chen, Z., Ouyang, Y., Hao, J., Xiong, Z. — Fri, 20 Nov 2009 08:02:32 PST

The location awareness is a crucial foundation for perceptions of the surroundings in the smart environment. Radio frequency identification (RFID), as one of the most promising technologies, plays a more important role in the indoor location awareness. This paper surveys current RFID-based locating research and discusses the problem that is brought by the tag's diversity derived from different manufacturer types and different used-time of built-in battery. We present the algorithm named RFDiffFreeLoc to improve the location precision by eliminating the dissimilarity among tags. In the stimulation experiments, we analyze the impact of noise on performance and contrast our algorithm with the existing LANDMARC algorithm. The simulation performances show that our algorithm is feasible via two metrics: the mean error and cumulative error distribution. The results indicate that RFDiffFreeLoc significantly increases the locating accuracy: when the space between the reference tags is 1 m, the mean error drops 0.076–0.344 m according to various noise conditions. Furthermore, a prototype system named RFHome is deployed for validating the algorithm in the actual home environment. The practical experimental results demonstrate that our algorithm is more effective than previous LANDMARC algorithm.

Multi-Agent Group Programming Based On Co-evolution

Wenjun, L., Tianjiang, W., Fang, L. — Fri, 20 Nov 2009 08:02:32 PST

As an effective means of multi-agent problem solving, autonomous individual programming and interaction that are essential need, are limited in their ability to accommodate the interests of others, and therefore, may unnecessarily constrain the solving ability and negotiability of an agent, particularly in a distributed cooperative environments founded on private and uncertain information. In this paper, a multi-agent group programming model is presented, where each agent executes local programming by evolutionary search. Based on co-evolution idea, agents resolve conflicts and revise their own search direction to optimize local and social objectives in an interactive process by means of clustering and group choice. Finally, the paper presents simulation results that illustrate the operational effectiveness of our agent group programming model.

Ambient Ecologies in Smart Homes

Goumopoulos, C., Kameas, A. — Fri, 20 Nov 2009 08:02:32 PST

An important characteristic of ubiquitous computing (UbiComp) environments is the integration of information, communication and sensing technologies into our everyday objects, giving rise to a new proactive computing model in homes. A smart home uses networked sensors, devices and appliances to build an intelligent environment in which many activities in the home are automated and where devices and services seamlessly cooperate to support domestic tasks. Programming and maintaining such an infrastructure is challenging because suitable abstractions are currently missing. In this work we have attempted to define ambient ecologies as a metaphor for modeling UbiComp applications, specify design patterns and programming principles and develop infrastructure to provide a paradigm of application engineering and tools to support ambient ecology designers, developers and end-users. We describe our model and the middleware architecture and present the engineering of applications in a smart home environment.

Optimizing Access Point Allocation Using Genetic Algorithmic Approach for Smart Home Environments

Lee, J.-H., Han, B.-J., Lim, H.-J., Kim, Y.-D., Saxena, N., Chung, T.-M. — Fri, 20 Nov 2009 08:02:32 PST

In recent years, high-bandwidth and low-cost wireless technologies have emerged as a competitive element, enabling the smart home environment. On the other hand, with the increasing demands for various services, the current access point allocation schemes give rise to significant challenges for a stable connection service, bandwidth and load distribution. In this paper, we present an optimal access point allocation scheme based on genetic algorithm that attempts to optimize multiple parameters, such as bandwidth, and load-balancing requirements. The proposed allocation scheme provides a set of approximately efficient solutions, which allows a wireless user to choose an access point based on its capacity and load balancing, not only regarding its signaling strength or service set identifier. The simulation results are provided to demonstrate the impact of the proposed optimization procedure on overall system performance in terms of connection distribution, load balancing and call dropping probability.

Joint Routing and Rate Control Scheme for Multi-Stream High-Definition Video Transmission over Wireless Home Networks

Zhou, L., Zheng, B., Wei, A., Geller, B., Cui, J. — Fri, 20 Nov 2009 08:02:32 PST

The support for multiple high-definition video streams in wireless home networks requires appropriate routing and rate control measures, ascertaining the reasonable links for transmitting each stream and the rate of the video to be delivered over the chosen links. In this paper, we invest the combination of the routing and rate control in a united convex optimization formulation and propose a distributed joint solution based on cross-layer design. We first develop a distortion model which captures both the impact of encoder quantization and packet loss due to network congestion on the overall video quality. Then, the optimal joint rate control and routing scheme is realized by adapting its rate to the time-varying traffic and minimizing the overall network congestion. Furthermore, simulation results are provided, which demonstrate the effectiveness of our proposed joint routing and rate control scheme in the context of wireless home networks.

Design and Implementation of the DLNA Family Intercom System for Smart Homes

Lai, C.-F., Huang, H.-C., Huang, Y.-M., Chao, H.-C. — Fri, 20 Nov 2009 08:02:32 PST

In a traditional intercom system that only allows place-to-place communication in a house, it is necessary to dial the extension number of a specific family member, or dial each extension number individually via the intercom broadcasting, in order to reach the desired person. Additional master stations controlled the intercom system are required, and it is load to maintain the stations for general users. In order to solve these problems, we propose the digital living network alliance (DLNA) compatible family intercom system (DFIS): the architecture to support user mobility. This architecture makes it possible to quickly reach a family member without the knowledge of the extension number that caters to a fixed location. In other words, it will be not necessary to dial the extension number of the location of the desired person. We introduce call control and phone handling under the subject of DFIS architecture and demonstrate that the proposed DLNA family intercom device and DLNA family intercom adaptor can work well.

An Efficient Lossless Compression Algorithm for Tiny Nodes of Monitoring Wireless Sensor Networks

Marcelloni, F., Vecchio, M. — Fri, 20 Nov 2009 08:02:32 PST

Energy is a primary constraint in the design and deployment of wireless sensor networks (WSNs), since sensor nodes are typically powered by batteries with a limited capacity. Energy efficiency is generally achieved by reducing radio communication, for instance, limiting transmission/reception of data. Data compression can be a valuable tool in this direction. The limited resources available in a sensor node demand, however, the development of specifically designed compression algorithms. In this paper, we propose a simple lossless entropy compression (LEC) algorithm which can be implemented in a few lines of code, requires very low computational power, compresses data on the fly and uses a very small dictionary whose size is determined by the resolution of the analog-to-digital converter. We have evaluated the effectiveness of LEC by compressing four temperature and relative humidity data sets collected by real WSNs, and solar radiation, seismic and ECG data sets. We have obtained compression ratios up to 70.81% and 62.08% for temperature and relative humidity data sets, respectively, and of the order of 70% for the other data sets. Then, we have shown that LEC outperforms two specifically designed compression algorithms for WSNs. Finally, we have compared LEC with gzip, bzip2, rar, classical Huffman and arithmetic encodings.

Effective and Efficient Event Dissemination for RFID Applications

Jin, B., Zhao, X., Long, Z., Qi, F., Yu, S. — Fri, 20 Nov 2009 08:02:32 PST

The adoption of radio frequency identification (RFID) tags and devices facilitates the observation and monitoring of event patterns, while highly temporal restrained RFID data further make events complicated. Although the existing Pub/Sub systems can help distributed applications monitor and disseminate interesting events, they are unable to express RFID-related events directly. Extending a system for new RFID requirements not only needs a lot of work, but also provides no performance guarantees. It is, therefore, necessary to design and implement an effective and efficient Pub/Sub system in order to capture and disseminate RFID-related events. This paper presents a composite subscription specification for RFID-related application scenarios. It enables the subscription of predicates for RFID code as well as various complex events. Moreover, this paper proposes the algorithms for RFID-code subscription matching and complex events detection which have been implemented in our Pub/Sub system, OncePubSub. Also, experiments were conducted to quantify the performance and overhead of the above algorithms. Performance evaluation results indicate that OncePubSub is more efficient than SIENA- and JESS-based systems.

B2B Services: Worksheet-Driven Development of Modeling Artifacts and Code

Huemer, C., Liegl, P., Schuster, R., Zapletal, M. — Fri, 20 Nov 2009 08:02:32 PST

In the development process of a B2B system, it is crucial that the business experts are able to express and evaluate agreements and commitments between the partners, and that the software engineers get all necessary information to bind the private process interfaces to the public ones. UN/CEFACT's modeling methodology (UMM) is a Unified Modeling Language (UML) profile for developing B2B processes. The formalisms introduced by UMM's stereotypes facilitate the communication with the software engineers. However, business experts—who usually have a very limited understanding of UML—prefer expressing their thoughts and evaluating the results by plain text descriptions. In this paper, we describe an approach that presents an equivalent of the UMM stereotypes and tagged values in text-based templates called worksheets. This strong alignment allows an integration into a UMM modeling tool and ensures consistency. We show how a specially designed XML-based worksheet definition language allows customization to special needs of certain business domains. Furthermore, we demonstrate how information kept in worksheets may be used for the semi-automatic generation of pattern-based UMM artifacts which are later transformed to web service definition language and business process execution language code.

Special Issue on Profiling Expertise and Behaviour

Mirkin, B., Levene, M. — Tue, 13 Oct 2009 09:21:18 PDT

Searching for Expertise: Experiments with the Voting Model

Macdonald, C., Ounis, I. — Tue, 13 Oct 2009 09:21:18 PDT

In an expert search task, the user's need is to identify people who have relevant expertise to a topic of interest. An expert search system predicts and ranks the expertise of a set of candidate persons with respect to the user's query. In this work, we propose a novel approach for estimating and ranking candidate expertise with respect to a query. We see the problem of ranking experts as a voting problem, which we model using adaptations of data fusion techniques. We extensively investigate the effectiveness of the voting approach and the associated data fusion techniques across a range of document weighting models, in the context of the TREC 2005 and TREC 2006 Enterprise track settings. The evaluation results show that the voting paradigm is very effective, without using any collection-specific heuristics. Additionally, we further analyse two main features of the voting model, namely the manner in which document votes are combined and the effect of the underlying document ranking. First, for the combination of document votes, we hypothesise that candidate with large profiles can introduce bias in the generated ranking of candidates. We propose and integrate into the model a candidate length normalisation technique that removes bias towards prolific candidate experts. Secondly, we investigate the relative effects of applying various retrieval enhancing techniques to improve the quality of the underlying document ranking, to investigate how each technique improves the retrieval effectiveness of the generated ranking of candidates. At each stage, we experiment extensively and draw conclusions. Our results show that the voting techniques proposed are indeed effective, across several different document weighting models and settings. Secondly, we see that candidate profile length normalisation can help improve retrieval accuracy when applied to the candidate profile sets. Lastly, we show that increasing the quality of the underlying ranking of candidates can enhance the retrieval accuracy of the generated ranking of candidates.

Realizing Comprehensive User Profile as the Core Element of Adaptive and Personalized Communication Environments and Systems

Germanakos, P., Tsianos, N., Lekkas, Z., Mourlas, C., Samaras, G. — Tue, 13 Oct 2009 09:21:18 PDT

Challenges today in the Web personalization and adaptation research area range from heterogeneous user needs and user environment issues such as current location and time to multi-channel delivery of applications concerning Web-based content related to services, educational multimedia, entertainment, commerce, etc. Nowadays, most Web personalization systems implement various techniques to extract the user profiles, which serve as the main component of such systems. Based on given user preferences and navigation behavior, the Web-based content returns the requested personalized result. The main scope of this paper is to present the various techniques employed by such systems with regard to extraction of user profiles and to introduce a comprehensive user profilethat includes user perceptual preference characteristics. It further analyzes the main intrinsic user characteristics such as visual, cognitive and emotional-processing parameters that are incorporated as well as the ‘traditional’ user profile characteristics that together tend to give the most optimized, adapted and personalized outcome. It finally presents a Web adaptation and personalization system that implements the proposed comprehensive user profile as well as the initial evaluation results.

Interest Drifts in User Profiling: A Relevance-Based Approach and Analysis of Scenarios

Godoy, D., Amandi, A. — Tue, 13 Oct 2009 09:21:18 PDT

For personal information agents, user profiles have to represent user interests and preferences in order to satisfy long-term information needs. An implicit assumption in user-profiling is the existence of persistent interests which, however, might suffer some changes over time. Each time the interests of a user change, his profile becomes inaccurate and the predictive quality decreases. Adaptation of user profiles is, therefore, an essential requirement for personal agents that need to be capable of adjusting their behavior quickly in order to shorten the period of reduced predictive quality. In this paper, a user-profiling technique named WebProfiler, which learns a hierarchical representation of user interests using conceptual clustering, is augmented with an adaptation strategy based on relevance feedback and time-based forgetting in order to deal with drifting interests. We empirically evaluate the performance of this strategy by analyzing its behavior on multiple scenarios of interest drifts and shifts.

i-ProSE: Inferring User Profiles in a Scientific Context

Vivacqua, A. S., Oliveira, J., de Souza, J. M. — Tue, 13 Oct 2009 09:21:18 PDT

Scientific environments are known for being highly dynamic, subject to rapid evolution and demanding constant renewal and update. Additionally, science is a highly social arena. However, interpersonal collaboration and knowledge flow in scientific environments are usually more restricted. Collaboration is intense among small groups of people working on specific problems within a domain, but low between groups. As user profiling has been extensively used as a basis for recommendation, personalization and matchmaking systems, a better profile identification can improve interaction levels among researchers belonging to the same domain but working in different laboratories. Profiles may be constructed in two ways: either through explicit declaration by the user or through the observation of users’ actions. Many systems employ one approach to the exclusion of the other. We contend that a combined approach will yield better results, especially on scientific scenario, providing a mix of declared and inferred information. In this article, we present inference-based profiles in scientific environments (i-ProSE), an integrated system that dynamically creates and maintains scientific user profiles based both on declared information and on observed behaviour. The i-ProSE can be used to locate experts, deliver content, build communities, find collaborators for long-term projects or detect instantaneous opportunities for informal collaboration, which is presented with a short study case.

Enumerating Proofs of Positive Formulae

Dowek, G., Jiang, Y. — Tue, 13 Oct 2009 09:21:18 PDT

We provide a semi-grammatical description of the set of normal proofs of positive formulae in minimal predicate logic, i.e. a grammar that generates a set of schemes, from each of which we can produce a finite number of normal proofs. This method is complete in the sense that each normal proof-term of the formula is produced by some scheme generated by the grammar. As a corollary, we get a similar description of the set of normal proofs of positive formulae for a large class of theories including simple type theory and System F.

Semantic Analysis of Field Sports Video using a Petri-Net of Audio-Visual Concepts

Bai, L., Lao, S., Smeaton, A. F., O'Connor, N. E., Sadlier, D., Sinclair, D. — Tue, 13 Oct 2009 09:21:18 PDT

The most common approach to automatic summarization and highlight detection in sports video is to train an automatic classifier to detect semantic highlights based on occurrences of low-level features such as action replays, excited commentators or changes in a scoreboard. We propose an alternative approach based on the detection of perception concepts (PCs) and the construction of Petri-Nets, which can be used for both semantic description and event detection within sports videos. Low-level algorithms to detect PCs using visual, aural and motion characteristics are proposed, and a series of Petri-Nets composed of PCs is formally defined to describe video content. We call this a perception concept network–Petri-Net (PCN–PN) model. Using PCN–PNs, personalized high-level semantic descriptions of video highlights can be facilitated and queries on high-level semantics can be achieved. A particular strength of this framework is that we can easily build semantic detectors based on PCN–PNs to search within sports videos and locate interesting events. Experimental results based on recorded sports video data across three types of sports games (soccer, basketball and rugby), and each from multiple broadcasters, are used to illustrate the potential of this framework.

{lambda}_SAOP: A Security AOP Calculus

Alhadidi, D., Belblidia, N., Debbabi, M., Bhattacharya, P. — Tue, 13 Oct 2009 09:21:19 PDT

This paper presents an aspect-oriented calculus for security called _SAOP. It is based on the _calculus and contains pointcuts that are relevant to security hardening of applications. The main contribution of the paper is a semantics for _SAOP advice weaving in the presence of these pointcuts. We instrument the effect-based type inference system to inject advices into expressions during static typing. The proposed semantics for advice weaving is in the spirit of AspectJ, a prominent aspect-oriented programming language, where advices are injected before, after or around the join points that match their respective pointcuts. For this purpose, we accommodate the effect-based inference algorithm to take matching and weaving processes into consideration. In addition, we establish the required soundness and preservation proofs.

ALISON PHIPPS * Women in Science, Engineering and Technology: Three Decades of UK Initiatives. Trentham Books (2008). ISBN-13: 978 1 85856 402 9. {pound}16.99. 184 pp. Paperback.

Harrin, E. — Tue, 13 Oct 2009 09:21:19 PDT

Three Generalizations to a Generic Integrated Test Generation Method for Finite State Machines

Kapus-Kolar, M. — Fri, 21 Aug 2009 09:01:19 PDT

In a previous paper, we proposed a generic test generation method for deterministic implementations of deterministic finite state machines. The method supports a wide class of testing strategies, multi-criteria optimization and integrated handling of all the usual optimization concerns. The present paper generalizes the method to an even wider class of strategies, to non-deterministic machines and to machines handling data.

A Phase-Based Approach for On-Chip Bus Architecture Optimization

Lee, J., Lee, H.-J., Lee, C. — Fri, 21 Aug 2009 09:01:19 PDT

As the integration scale of a chip increases, on-chip interconnects suffer from the increased area occupied by a large number of bus signals. To reduce the overhead for communication, this paper formulates a new concept of an on-chip communication approach, called phase-based interconnection, with an example protocol, system-on-chip network protocol (SNP). In the phase-based communication, a small number of signals called phase signals are used to distinguish the types of signals transmitted through the main communication channel. To identify transactions transmitted through the channel, the SNP protocol defines the allowed sequence of phases for each transaction. A theoretical framework provides conditions for a phase-based protocol to allow immediate decoding of transactions. Simulation results show that the bandwidth of SNP is greater than that of a de facto standard bus protocol although SNP has wires only about three-fifths of the standard bus protocol. Although the signal-toggling rate is increased because of the multiplexed transmission of various signals through a single communication channel, simulation results show that the increase is not significant for multimedia applications that frequently transmit burst transfers. The phase omission of SNP helps to reduce the transaction failure rate to 65% while the hardware implementation cost for the support of phase omission is negligible.

Provably Secure Password-Based Three-Party Key Exchange With Optimal Message Steps

Chien, H.-Y., Wu, T.-C. — Fri, 21 Aug 2009 09:01:19 PDT

A password-based three-party encrypted key exchange (3PEKE) is a protocol that enables any pair of two registered clients to establish session keys with the help of a trusted server such that each client shares only one password with the server. This approach greatly improves the scalability of key agreement protocol in distributed environments and provides great user convenience. This article proposes a new password-based 3PEKE scheme that completes its entire job in only a record low four steps, which we prove that it is optimal for password-based 3PEKE protocols. The security of the proposed scheme, as we will detail later, has been proved in the random oracle model.

Design and Evaluation of a Distributed Clustering Algorithm for Mobile ad hoc Networks

Lacks, D., Chatterjee, M., Kocak, T. — Fri, 21 Aug 2009 09:01:19 PDT

This paper proposes a new clustering algorithm for global positioning system (GPS)-based mobile ad hoc networks that takes into consideration the direction of the overall traffic flow in the network. The proposed cluster leader logic algorithm is motivated by the GPS quorum hybrid routing algorithm, where clusterheads are positioned on the terrain upon a conceptual cellular grid. The proposed distributed clustering algorithm chooses the clusterheads based on the traffic flow patterns, i.e. the nodes best suited to forward and route network traffic are selected. Our approach allows a clusterhead which is overwhelmed with sending packets to identify an additional clusterhead from nodes available in its cell to share its load. Likewise, clusterheads with low load will try to relinquish their role as a clusterhead. We propose a new concept called cell fanning that allows collocated clusterheads in one cell to share routing responsibilities by declaring which cells they are responsible for routing packets to. We conducted extensive simulation experiments with enforced directional traffic patterns. Two important results are presented: power consumption per clusterhead and average queuing delay for each clusterhead. Results in terms of message overheads, number of clusterheads, power consumption, and queuing delay reveal that system performance is enhanced when clusterheads are chosen considering the direction of the traffic flow.

Just-In-Time Cache for Capsule-Based Active Networks

Huang, T.-C., Shieh, C.-K., Miao, Y.-B. — Fri, 21 Aug 2009 09:01:19 PDT

Active networking introduces a novel programming paradigm to applications by injecting codes into networks in order to program them. Among the approaches to injecting codes into networks, active networking attracts most research communities to explore the capsule-based active network, where the packet named the capsule can carry codes and data together to customize the processing of the packet in network devices with the codes. Because a capsule has space limitations that harm application developments in capsule-based active networks, the just-in-time cache (JITC) is proposed to alleviate capsule space limitations. The JITC is an innovative idea to introduce a cache into a capsule besides into a network device. The JITC automatically tailors codes to the need of a capsule while processing the capsule in a network device. The JITC allows a capsule merely to carry the necessary codes to traverse active networks and makes a network device download codes on behalf of the capsule on demand. The JITC allows applications to disable the cache, control the cache size, and specify the required cache placement policy in a capsule to achieve the optimal performance. Currently, the JITC supports six canonical cache placement policies. The JITC is implemented in Windows 2000 as a proof of concept. In the experiments, the JITC has trivial overheads in contrast to other common overheads in the existing solutions. The JITC outperforms the existing solutions in throughput, processing delay, resource sensitivity, and bandwidth conservation in the cache-policy-free situation. Besides, the JITC has examples for the six cache placement policies to demonstrate the performance improvement with each of them.

Implications of Electronics Technology Trends for Algorithm Design

Greenfield, D., Moore, S. — Fri, 21 Aug 2009 09:01:19 PDT

Scaling of electronics technology has brought us to a pivotal point in the design of computational devices. Technology scaling favours transistors over wires which has led us into an era where communication takes more time and consumes more power than the computation itself. This technology driver inevitably pushes us toward a communication-centric approach to algorithm design. To assess the efficiency of an algorithm we will need to be able to predict data movement both in time and space. We demonstrate that algorithms exhibit fractal like communication behaviour which is likely to help with such an analysis. Moreover, successfully exploiting these fractal properties will allow us to reduce communication, thereby increasing performance and power efficiency.

A Digest and Pattern Matching-Based Intrusion Detection Engine

Chen, Z., Zhang, Y., Chen, Z., Delis, A. — Fri, 21 Aug 2009 09:01:19 PDT

Intrusion detection/prevention systems (IDSs/IPSs) heavily rely on signature databases and pattern matching (PM) techniques to identify network attacks. The engines of such systems often employ traditional PM algorithms to search for telltale patterns in network flows. The observations that real-world network traffic is largely legitimate and that telltales manifested by exploits rarely appear in network streams lead us to the proposal of Fingerprinter. This framework integrates fingerprinting and PM methods to rapidly distinguish well-behaved from malicious traffic. Fingerprinter produces concise digests or fingerprints for attack signatures during its programming phase. In its querying phase, the framework quickly identifies attack-free connections by transforming input traffic into its fingerprint space and matching its digest against those of attack signatures. If the legitimacy of a stream cannot be determined by fingerprints alone, our framework uses the Boyer–Moore algorithm to ascertain whether attack signatures appear in the stream. To reduce false matches, we resort to multiple fingerprinting techniques including Bloom–Filter and Rabin–Fingerprint. Experimentation with a prototype and a variety of traces has helped us establish that Fingerprinter significantly accelerates the attack detection process.

YVES POCHET AND LAURENCE A. WOLSEY * Production Planning Using Mixed Integer Programming. * Springer (2006). ISBN 978-0-387-29959-4. {pound}38.50/$59.95. * 477 pp. Hardbound.

Marecek, J. — Fri, 21 Aug 2009 09:01:19 PDT

JEAN TABAKA * Collaboration Explained: Facilitation Skills for Software Project Leaders. Addison Wesley (2006). ISBN-13 978-0321268778. {pound}31.99. 412 pp. Softbound.

Harrin, E. — Fri, 21 Aug 2009 09:01:19 PDT

COLLEEN MCCUE * Data Mining and Predictive Analytics: Intelligence Gathering and Crime Analysis. Elsevier (2007). ISBN 0-7506-7796-1. 28.99 GBP. 332 pp. Paper back.

Refaat, M. — Fri, 21 Aug 2009 09:01:19 PDT