Realist Activity Theory for Digital Library Evaluation: Conceptual Framework and Case Study

A critical yet largely unexamined facet of digital library design anduse is how library content is assembled and vetted, which in turn hasprofound implications for ongoing digital library usefulness and usability.This article presents a social realist evaluation framework for anactivity theoretic case study of the Flora of North America digitallibrary. Social realist evaluation is a relatively new evaluationparadigm, positing that outcomes follow from mechanisms acting incontingently configured contexts. Because this study focuses on thedigital library content vetting process, a significant part of thepresent analysis concerns the publication subsystem of the Flora ofNorth America digital library – Collaborative Publishing Services –and how problems related to its design and use facilitates our abilityto explain the Flora of North America not only as a functioning digitallibrary project, but as a contradiction-driven organizational form inexpansive development. Activity theory is a philosophical and cross-disciplinaryframework for studying different forms of human practices in a multi-level,stratified manner, developmentally in time and through space. This intensivecase study of the Flora of North America digital library illustrates thatwhile social realism, itself content-neutral mechanics of explanation,provides a real foundation for activity theoretic analyses of workand technology, activity theory supplies a conceptually and substantivelyrich vocabulary for explanatory reasoning about technologically mediatedsocial practices, such as digital library assemblage and use.     

Bi-modal breast cancer classification system

Breast cancer is known as one of the major causes of mortality among women. Breast cancer can be treated with better patient outcomes and significantly lower costs if it is detected early. Digital mammograms are the type of medical images most often used, and which are the most reliable, for the detection of breast cancer. The presence of microcalcification clusters in mammograms contributes to evidence for the detection of early stages of cancer. In this paper, a bi-modal artificial neural network (ANN) based breast cancer classification system is proposed. The microcalcifications are extracted with adaptive neural networks that are trained with cancer/malignant and normal/benign breast digital mammograms of both cranio caudal (CC) and medio-latral oblique (MLO) views. The performance of the networks is evaluated using receiver operating characteristic (ROC) curve analysis. Sensitivity–specificity of 98.0–100.0 for the CC view and 96.0–100.0 for the MLO view networks are recorded for 200 unseen digital database for screening mammography (DDSM) cases. The DDSM database, developed at the University of South Florida, is a resource for use by the mammographic image analysis research community. The OR logic is then used to fuse individual networks to get a best sensitivity–specificity of 100.0–100.0 for the ensemble. However, the overall sensitivity–specificity of the ANN ensemble is somewhat degraded at the expense of a robust or sensitive system, i.e., the probability to miss out a true positive case is minimized.     

Evolutionary virus immune strategy for temporal networks based on community vitality

Preventing viruses spreading in networks is a hot topic. Existing immune strategies are mainly designed for static networks, which become ineffective for temporal networks. In this paper, we propose an evolutionary virus immune strategy for temporal networks, which takes into account the community evolution. First, we define a new metric, community vitality (CV), to quantize the evolution characteristics of communities. Second, based on the community vitality, we propose an immune strategy which selects an optimized number of initial nodes according to node influence (NI). Third, a theoretical analysis is proposed to measure the immune effect of the evolutionary immune strategy. Compared with the random immunization, the targeted immunization and the acquaintance immune strategy, we show that the proposed strategy has a much larger coverage, i.e., more nodes will have immune ability given the same number of initial immune nodes.     

Internet addiction: Meta-synthesis of qualitative research for the decade 1996–2006

Internet addiction is “an individual’s inability to control their Internet use, which in turn leads to feelings of distress and functional impairment of daily activities” [Shapira, N., Lessig, M., Goldsmith, T., Szabo, S., Lazoritz, M., Gold, M. et al. (2003). Problematic Internet use: Proposed classification and diagnostic criteria. Depression and Anxiety, 17(4), 207–216]. Previous research in this field has offered inconclusive data on whether Internet addiction can be classified as a disorder. This study provides an in-depth and comprehensive analysis of internet addiction through a meta-synthesis of qualitative studies on excessive Internet use published during the period of 1996–2006. Several constructs pertaining to the domain of Internet addiction have been identified and a theoretical model of Internet addiction has been proposed.     

基于Kullback-Leibler距离的二分网络社区发现方法

现实世界存在大量二分网络,研究二分社区结构有助于从新角度认识和理解复杂网络。由于二分网络特殊的二分结构,使得基于单模网络的现有社区发现算法无法适用。本文提出一种基于Kullback-Leibler距离的二分网络社区发现算法,该算法将异质节点间的连接关系转化为其在用户节点集上的连接概率分布,并建立基于概率分布的KL相似度衡量节点连接模式的差异性,从而克服二分结构对节点相似性评估的不利影响,实现对二分网络异质节点的社区发现。在人工网络和真实网络上的实验和分析表明：该算法能够有效挖掘二分网络社区结构,改善二分网络社区发现的准确性和效率。     

A duality based framework for integrating reliability and precision for sensor network design

In sensor network design literature, requirements such as maximization of the network reliability [Y. Ali, S. Narasimhan, Sensor network design for maximizing reliability of linear processes, AIChE J. 39 (1993) 820–828; Y. Ali, S. Narasimhan, Redundant sensor network design for linear processes, AIChE J. 41 (1995) 2237–2249] and minimization of cost subject to precision constraints [M. Bagajewicz, Design and retrofit of sensor networks in process plants, AIChE J. 43 (1997) 2300–2306; M. Bagajewicz, E. Cabrera, New MILP formulation for instrumentation network design and upgrade, AIChE J. 48 (2002) 2271–2282] have been proposed as a criteria for optimally locating sensors. In this article, we show that the problems of maximizing reliability and maximizing precision (or minimizing variance) for linear processes are dual of each other. To achieve this duality, we propose transformations which can be used to convert sensor failure probabilities into equivalent sensor variances and vice versa. Thus, the duality enables working in a single framework with specified criteria on reliability as well as precision. As an application of this duality, we propose two formulations for the sensor network design problem viz., maximization of the network reliability subject to precision constraints and minimization of the network variance subject to reliability constraints. We also show the utility of these formulations to determine the pareto-front for the combinatorial sensor network design problem. Hydrodealkylation and steam-metering case studies are used to illustrate the proposed ideas.     

Performance comparison of routing algorithms in wormhole-switched networks

This paper presents, building on the analytical models developed in [A. Shahrabi, M. Ould-Khoua, L. Mackenzie, Performance modelling of broadcast communication in multicomputer networks, International Journal of Parallel, Emergent, and Distributed Systems 20 (1) (2005); A. Shahrabi, M. Ould-Khoua, On the communication latency of wormhole routed interconnection networks, International Journal of Simulation 4 (5–6) (2003) 32–43; A. Shahrabi, L. Mackenzie, M. Ould-Khoua, Modelling of Adaptive Wormhole-Routed Hypercubes in the Presence of Broadcast Traffic, in: N.J. Dimopoulos, K.F. Li (Eds.), Chapter 10 in High Performance Computing Systems And Applications, Kluwer Academic Publishers, Boston, 2002; A. Shahrabi, M. Ould-Khoua, L. Mackenzie, An Analytical Model of Wormhole-Routed Hypercubes under Broadcast Traffic, Performance Evaluation 53 (1) (2003) 23–42; A. Shahrabi, M. Ould-Khoua, L. Mackenzie, Latency of double-tree broadcast in wormhole-routed hypercubes, in: Proceedings of International Conference on Parallel Processing (ICPP’01), IEEE Computer Society, 2001, pp. 401–408] a comparative performance study of adaptive and deterministic routing algorithms in wormhole-switched interconnection networks carrying a broadcast traffic component and investigates the performance vicissitudes of them under a variety of network operating conditions. In contrast to previous works, which have reported superiority of adaptive over deterministic routing especially in high-dimensional networks such as hypercubes, our results show that adaptivity does not necessarily improve network performance even for high-dimensional networks and its superiority starts to deteriorate as the broadcast fraction of generated traffic increases.     

Building an IP-based community wireless mesh network: Assessment of PACMAN as an IP address autoconfiguration protocol

Wireless mesh networks are experiencing rapid progress and inspiring numerous applications in different scenarios, due to features such as autoconfiguration, self-healing, connectivity coverage extension and support for dynamic topologies. These particular characteristics make wireless mesh networks an appropriate architectural basis for the design of easy-to-deploy community or neighbourhood networks. One of the main challenges in building a community network using mesh networks is the minimisation of user intervention in the IP address configuration of the network nodes. In this paper we first consider the process of building an IP-based mesh network using typical residential routers, exploring the options for the configuration of their wireless interfaces. Then we focus on IP address autoconfiguration, identifying the specific requirements for community mesh networks and analysing the applicability of existing solutions. As a result of that analysis, we select PACMAN, an efficient distributed address autoconfiguration mechanism originally designed for ad-hoc networks, and we perform an experimental study – using off-the-shelf routers and assuming worst-case scenarios – analysing its behaviour as an IP address autoconfiguration mechanism for community wireless mesh networks. The results of the conducted assessment show that PACMAN meets all the identified requirements of the community scenario.     

Dynamics of social roles in a knowledge management community

With the emergence of community-oriented Information and Communication Technology (ICT) applications, e.g., Wikipedia, the popularity of socio-technical phenomena in society has increased. This development emphasises the need to further our understanding of how computer-supported social group structures change over time and what forms emerge. This contribution presents the results of a qualitative field study of a Socio-Technical Community (STC). The STC is described from its founding (in 2001) to its sustainable development (in 2006) as well as its transformation phase (2007–2008). The design-based research approach revealed changes of social structures by social roles within the STC over time. The central conclusion is that such STC’s – networks of computer-mediated communication and human interaction – evolve a specific kind of social structure, which is formal rather than informal. The results indicate that a group evolves from an informal trust-based community with few formal roles to a STC where the social mechanisms, and not the software architecture, supports knowledge management processes.     

A simple, least-time, and energy-efficient routing protocol with one-level data aggregation for wireless sensor networks

The area of wireless sensor networks (WSN) is currently attractive in the research community area due to its applications in diverse fields such as defense security, civilian applications and medical research. Routing is a serious issue in WSN due to the use of computationally-constrained and resource-constrained micro-sensors. These constraints prohibit the deployment of traditional routing protocols designed for other ad hoc wireless networks. Any routing protocol designed for use in WSN should be reliable, energy-efficient and should increase the lifetime of the network. We propose a simple, least-time, energy-efficient routing protocol with one-level data aggregation that ensures increased life time for the network. The proposed protocol was compared with popular ad hoc and sensor network routing protocols, viz., AODV ( [35] and [12]), DSR (Johnson et al., 2001), DSDV (Perkins and Bhagwat, 1994), DD (Intanagonwiwat et al., 2000) and MCF (Ye et al., 2001). It was observed that the proposed protocol outperformed them in throughput, latency, average energy consumption and average network lifetime. The proposed protocol uses absolute time and node energy as the criteria for routing, this ensures reliability and congestion avoidance.     

A multi-path mechanism for reliable VoIP transmission over wireless networks

With the advances in audio encoding standards and wireless access networks, voice over IP (VoIP) is becoming quite popular. However, real-time voice data over lossy networks (such as WLAN and UMTS), still posses several challenging problems because of the adverse effects caused by complex network dynamics. One approach to provide QoS for VoIP applications over the wireless networks is to use multiple paths to deliver VoIP data destined for a particular receiver. This paper introduced cmpSCTP, a transport layer solution for concurrent multi-path transfer that modifies the standard stream control transmission protocol (SCTP). The cmpSCTP aims at exploiting SCTP’s multi-homing capability by selecting several best paths among multiple available network interfaces to improve data transfer rate to the same multi-homed device. Through the use of path monitoring and packet allotment techniques, cmpSCTP tries to transmit an amount of packets corresponding to the path’s ability. At the same time, cmpSCTP updates the transmission strategy based on the real-time information of all of paths. Using cmpSCTP’s flexible path management capability, we may switch the flow between multiple paths automatically to realize seamless path handover. The theoretical analysis evaluated the model of cmpSCTP and formulated optimal traffic fragmentation of VoIP data. Extensive simulations under different scenarios using OPNET verified that cmpSCTP can effectively enhance VoIP transmission efficiency and highlighted the superiority of cmpSCTP against the other SCTP’s extension implementations under performance indexes such as throughput, handover latency, packet delay, and packet loss.     

融合先验信息的非负矩阵分解社区发现算法*

针对复杂网络社区发现问题,为了获得更准确、可解释性的社区划分结果,提出融合先验信息的半监督非负矩阵分解算法,给出优化目标的求解方法.文中算法利用先验信息直接约束社区指示矩阵,构造优化目标函数,获得更有意义的社区划分结果.真实数据集上的实验表明该算法的有效性,减小先验信息的融入对利用非负矩阵分解进行节点重要性等属性分析工作带来的不利影响,并且适用于加权和非加权等不同的网络.     

Community Detection in Complex Networks

With the rapidly growing evidence that various systems in nature and society can be modeled as complex networks, community detection in networks becomes a hot research topic in physics sociology, computer society, etc. Although this investigation of community structures has motivated many diverse algorithms, most of them are unsuitable when dealing with large networks due to their computational cost. In this paper, we present a faster algorithm ComTector which is more efficient for the community detection in large complex networks based on the nature of overlapping cliques. This algorithm does not require any priori knowledge about the number or the original division of the communities. With respect to practical applications, ComTector is challenging with five different types of networks including the classic Zachary Karate Club, Scientific Collaboration Network South Florida Free Word Association Network, Urban Traffic Network North America Power Grid and the Telecommunication Call Network. Experimental results show that our algorithm can discover meaningful communities that meet both the objective basis and our intuitions.     

An efficient password-based three-party authenticated multiple key exchange protocol for wireless mobile networks

With the rapid development of wireless mobile communication, the password-based three-party authenticated key exchange protocol has attracted an increasing amount of attention. To generate more session keys at one time for different applications, Li et al. proposed a password-based three-party authenticated multiple key exchange (3PAMKE) protocol for wireless mobile networks. They claimed that their protocol could withstand various attacks. In this paper, we will show Li et al.’s protocol is not secure off-line password guessing. Furthermore, we proposed an improved 3PAMKE protocol to overcome weakness in Li et al.’s protocol. Security analysis and performance analysis shows our protocol not only overcomes security weakness, but also has better performance. Therefore, our protocol is more suitable for wireless mobile networks.     

Modeling of high-affinity binding of the novel atrial anti-arrhythmic agent, vernakalant, to Kv1.5 channels

Vernakalant (RSD1235) is an investigational drug that converts atrial fibrillation rapidly and safely in patients intravenously [Roy et al., J. Am. Coll. Cardiol. 44 (2004) 2355–2361; Roy et al., Circulation 117 (2008) 1518–1525] and maintains sinus rhythm when given orally [Savelieva et al., Europace 10 (2008) 647–665]. Here, modeling using AutoDock4 allowed exploration of potential binding modes of vernakalant to the open-state of the Kv1.5 channel structure. Point mutations were made in the channel model based on earlier patch-clamp studies [Eldstrom et al., Mol. Pharmacol. 72 (2007) 1522–1534] and the docking simulations re-run to evaluate the ability of the docking software to predict changes in drug–channel interactions. Each AutoDock run predicted a binding conformation with an associated value for free energy of binding (FEB) in kcal/mol and an estimated inhibitory concentration (K_i). The most favored conformation had a FEB of −7.12 kcal/mol and a predicted K_i of 6.08 μM (the IC50 for vernakalant is 13.8 μM; [Eldstrom et al., Mol. Pharmacol. 72 (2007) 1522–1534]). This conformation makes contact with all four T480 residues and appears to be clearly positioned to block the channel pore.     

车载Ad Hoc网络MAC协议研究

在移动自组网中,MAC协议是保证移动终端能够公平有效地共享无线信道所不可缺少的手段.近年来,随着车载通信系统的不断发展和自组网技术日益成熟,如何将二者有机结合成车载自组网已引起业界的极大关注.由于VANET自身的特点,以及其支持的业务应用种类非常丰富,现有自组网的MAC协议并不能直接用于VANET中.在简要介绍Ad Hoc网络中MAC协议的基础上,对VANET的MAC协议研究进展进行了综述,并指出了该领域的发展趋势.     

Georoy: A location-aware enhancement to Viceroy peer-to-peer algorithm

The success of experiences such as Seattle and Houston Wireless has attracted the attention on the so called wireless mesh community networks. These are wireless multihop networks spontaneously deployed by users willing to share communication resources. Due to the community spirit characterizing such networks, it is likely that users will be willing to share other resources besides communication resources, such as data, images, music, movies, disk quotas for distributed backup, and so on. To support resource exchange in these wireless mesh community networks, algorithms for efficient retrieval of information are required. In this paper we introduce Georoy, an algorithm for the efficient retrieval of the information on resource location based on the Viceroy peer-to-peer algorithm. Differently from Viceroy, Georoy exploits the capability of setting and managing a direct mapping between the resource ID and the node which maintains information about its location so as to speed up the search process. Simulation results show that Georoy enables efficient and scalable search of resources and can be successfully used in wireless mesh community networks.     

无线网络入侵检测系统的设计与实现

文章详细介绍了一些适用于无线网络入侵检测的技术方法,并且结合我国目前对于无线网络的发展需要以及无线网络存在安全威胁,对提高无线网络入侵检测系统的设计与实现进行探讨。     

Space–Time Block Coding for Channels with Intersymbol Interference

Stoica, P., and Lindskog, E., Space–Time Block Coding for Channels with Intersymbol Interference, Digital Signal Processing12 (2002) 616–627The downlink of many wireless communication systems can be a MISO channel. An important problem for a MISO channel is how to code across space and time to obtain the same ML receiver as for the corresponding SIMO channel. For flat fading channels, space–time block coding (STBC) is a recent breakthrough solution to this problem. In Lindskog and Paulraj (in Proceedings of ICC'2000, NewOrleans, LA, June 18–22, 2000), STBC has been generalized to channels with intersymbol interference (ISI) for the case of two transmit antennas and one receive antenna. In this paper we first revisit the generalized STBC scheme of Lindskog and Paulraj and show that it has the same appealing properties as the standard STBC for flat fading channels. Then we go on to present an extension of this scheme to ISI channels with any number of transmit and receive antennas.     

Public opinion channel for communities in the information age

In this paper, we propose as a new challenge a public opinion channel which can provide a novel communication medium for sharing and exchanging opinions in a community. Rather than simply developing a means of investigating public opinion, we aim at an active medium that can facilitate mutual understanding, discussion, and public opinion formation. First, we elaborate the idea of public opinion channels and identify key issues. Second, we describe our first step towards the goal using the talking virtualized egos metaphor. Finally, we discuss a research agenda towards the goal. Toyoaki Nishida, Dr.Eng.: He is a professor of Department of Information and Communication Engineering, School of Engineering, The University of Tokyo. He received the B.E., the M.E., and the Doctor of Engineering degrees from Kyoto University in 1977, 1979, and 1984 respectively. His research centers on artificial intelligence in general. His current research focuses on community computing and support systems, including knowledge sharing, knowledge media, and agent technology. He has been leading the Breakthrough 21 Nishida Project, sponsored by Ministry of Posts and Telecommunications, Japan, aiming at understanding and assisting networked communities. Since 1997, he is a trustee for JSAI (Japanese Society for Artificial Intelligence), and serves as the program chair of 1999 JSAI Annual Convention. He is an area editor (intelligent systems) of New Generation Computing and an editor of Autonomous Agents and Multiagent Systems. Nobuhiko Fujihara, Ph.D.: He is a fellow of Breakthrough 21 Nishida project, Communications Research Laboratory sponsored by Ministry of Posts and Telecommunications, Japan. He received the B.E., the M.E., and the Ph.D. in Human Sciences degrees from Osaka University in 1992, 1994, and 1998 respectively. He has a cognitive psychological background. His current research focuses on: (1) cognitive psychological analysis of human behavior in a networked community, (2) investigation of information comprehension process, (3) assessment and proposition of communication tools in networking society. Shintaro Azechi: He is a fellow of Breakthrough 21 Nishida project, Communications Research Laboratory sponsored by Ministry of Posts and Telecommunications, Japan. He received the B.E. and the M.E. of Human Sciences degrees from Osaka University in 1994 and 1996 respectively. He is a Doctoral Candidate of Graduate School of Human Sciences, Osaka University. His current researches focus on (1) human behavior in networking community (2) social infomation process in human mind (3) development of acessment technique for communication tools in networkingsociety. His approach is from social psychological view. Kaoru Sumi, Dr.Eng.: She is a Researcher of Breakthrough 21 Nishida Project. She received her Bachelor of Science at School of Physics, Science University of Tokyo. She received her Master of Systems Management at Graduate School of Systems Management, The university of Tsukuba. She received her Doctor of engineering at Graduate School of Engineering, The University of Tokyo. Her research interests include knowledge-based systems, creativity supporting systems, and their applications for facilitating human collaboration. She is a member of the Information Processing Society of Japan (IPSJ), the Japanese Society for Artificial Intelligence (JSAI). Hiroyuki Yano, Dr.Eng.: He is a senior research official of Kansai Advanced Research Center, Communications Research Laboratory, Ministry of Posts and Telecommunications. He received the B.E., the M.E., and the Doctor of Engineering degrees from Tohoku University in 1986, 1988, and 1993 respectively. His interests of research include cognitive mechanism of human communications. His current research focuses on discourse structure, human interface, and dialogue systems for human natural dialogues. He is a member of the Japanese Society for Artificial Intelligence, the Association for Natural Language Processing, and the Japanese Cognitive Science Society. Takashi Hirata: He is a doctor course student in Graduate School of Information Scienc at Nara Institute of Science and Technology (NAIST). He received a master of engineering from NAIST in 1998. His research interest is knowledge media and knowledge sharing. He is a member of Information Processing Society of Japan (IPSJ), Japan Association for Artificial Intelligence (JSAI) and The Institute of Systems, Control and Information Engineers (ISCIE).