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Forecasts the wide availability and use of networked computers in homes and schools by the end of 1995. Systems to be used; Significant educational aspect of the coming connectivity; Impact of such a development on science education; Possible negative effects of the development; Strengthening of home education with technology; Implications of cabling.

The ability to produce timely and accurate flu forecasts in the United States can significantly impact public health. Augmenting forecasts with internet data has shown promise for improving forecast accuracy and timeliness in controlled settings, but results in practice are less convincing, as models augmented with internet data have not consistently outperformed models without internet data. In this paper, we perform a controlled experiment, taking into account data backfill, to improve clarity on the benefits and limitations of augmenting an already good flu forecasting model with internet-based nowcasts. Our results show that a good flu forecasting model can benefit from the augmentation of internet-based nowcasts in practice for all considered public health-relevant forecasting targets. The degree of forecast improvement due to nowcasting, however, is uneven across forecasting targets, with short-term forecasting targets seeing the largest improvements and seasonal targets such as the peak timing and intensity seeing relatively marginal improvements. The uneven forecasting improvements across targets hold even when “perfect” nowcasts are used. These findings suggest that further improvements to flu forecasting, particularly seasonal targets, will need to derive from other, non-nowcasting approaches. [ABSTRACT FROM AUTHOR]

In this paper we describe the creation and use of metadata on the early Arpanet as part of normal network function. By using the Arpanet Host-Host Protocol and its sockets as an entry point for studying the generation of metadata, we show that the development and function of key Arpanet infrastructure can be studied by examining the creation and stabilization of metadata. More specifically, we use the Host-Host Protocol's sockets as an example of something that, at the level of the network, functions as both network infrastructure and metadata simultaneously. By presenting the function of sockets in tandem with an overview of the Host-Host Protocol, we argue for the further integrated study of infrastructure and metadata. Finally, we reintroduce the concept of infradata to refer specifically to data that locate data throughout an infrastructure and are required by the infrastructure to function, separating them from established and stabilized standards. We argue for the future application of infradata as a concept for the study of histories and political economies of networks, bridging the largely library and information science (LIS) study of metadata with the largely science and technology studies (STS) domain of infrastructure. [ABSTRACT FROM AUTHOR]

Purpose - This paper aims to discuss the importance of developing a national communication and information infrastructure that meets near-term needs and capabilities. Design/methodology/approach - The current status of Electronic Frontier Foundation's Open Platform Proposal, which is based on narrowband ISDN implementation, is described. Findings - The advantages and drawbacks of Electronic Frontier Foundation's Open Platform Proposal are presented. Originality/value - The paper provides recommendations for public policy criteria that should be used in evaluating different infrastructure proposals. [ABSTRACT FROM AUTHOR]

The development of technologies that allow interoperable radios on a number of networked nodes for tactical scenarios has seen much interest in recent years. In particular, the Joint Tactical Radio System (JTRS) is one project aimed at designing interoperable tactical data links for a number of scenarios involving United States and coalition forces. The JTRS project was motivated by a number of factors concerning extant tactical data links. These factors include a lack of interoperability and the proprietary nature of the radios required, as well as the inability of such links to allow high-rate ad hoc networked communications in a highly mobile environment. It has been suggested that existing commercial off-the-shelf equipment could perhaps be used for tactical networking. Subsequently, in a previous paper by the author, preliminary results were presented for an example tactical networking scenario. In that paper, it was assumed that high-gain antennas could be used in such a way that they always provided maximum gain, irrespective of the locations of each node, and the types of antenna gain patterns that could be achieved with such antennas. Additionally, size, weight and power (SWAP) constraints were not considered. In this paper, SWAP constraints are considered in determining an example set of transmit power and antenna types to investigate the effects of such practical constraints on the data rates that could be achieved. Also, a single ground-reflector model is used for the wireless channel, instead of the line-of-sight only model assumed in the previous work. Results obtained by simulation of an adaptive orthogonal frequency division multiplexing scheme are provided for a range of possible asset separation distances. These results highlight both the effect of distance-dependent signal attenuation, and also antenna pointing mismatch. Such effects would need to be jointly considered when designing a high-rate tactical data network. [ABSTRACT FROM AUTHOR]

Purpose — This paper aims to provide an overview of the published literature and current use of social software by libraries primarily in the UK and USA. Design/methodology/approach — The paper's approach is a literature review and desk research. Findings — Libraries are experimenting considerably in this area and many Web 2.0 applications have been developed by libraries and librarians over the past few years. These tools offer the potential to enhance library services. Research limitations/implications — The area is one of rapid change, so the findings will date quickly. Practical implications — An overview of which technologies are being used most widely and might offer the most potential for library staff considering experimenting in this area. Originality/value of paper — Web 2.0 is an area with which many library staff need to become familiar quickly. This paper provides a useful overview of the topic. [ABSTRACT FROM AUTHOR]

The rapid deployment of information and communications technology (ICT) across the globe has led to a network of high-density computer data centers to store, process and transmit information. These large-scale technology warehouses consume vast amounts of energy for running the compute infrastructure and auxiliary cooling resources. Recent literature [7] has suggested the possibility of globally staggering compute workloads to take advantage of local climatic conditions as a means to reducing cooling energy costs. This paper further explores this premise by performing an in-depth analysis of the environmental and economic burden of managing the thermal infrastructure of a globally connected data center network. The paper examines a case study where the potential energy savings achievable by staggering workloads across arbitrarily chosen data centers in the U.S., India, and Russia are examined. The results show that the environmental benefit of such off-shoring is mostly dependent on the fuel mix of the grid to which the workload is transferred and the energy consumption in each location. Further, we show that dynamic optimization of the thermal workloads based on local weather patterns can reduce the environmental burden by up to 30%. The paper concludes with a detailed economic assessment. For the case study in this paper, we find that such global workload staggering can potentially reduce operational costs by nearly 35%. [ABSTRACT FROM AUTHOR]

There has been recent extensive research on integrating cellular networks and ad hoc networks to overcome the limitations of cellular networks. Although several schemes have been proposed to use such hybrid networks to improve the performance of individual multicast groups, they do not address quality of service (QoS) issues when multiple groups are present. This paper, on the other hand, considers an interesting scenario of hybrid networks when an ad hoc network cannot accommodate all the groups and a base station has to select a subset of groups to optimize its bandwidth savings and maximize the utilization of the ad hoc network while providing QoS support for multicast users. In this paper, a network model for multicast admission control that takes wireless interference into account is developed, the group selection problem is formulated as a multidimensional knapsack problem, and an integer linear programming (ILP) formulation and a polynomial-time dynamic algorithm are proposed. A distributed implementation of the dynamic algorithm in real systems is also examined. Simulation studies demonstrate that the dynamic algorithm is able to achieve very competitive performance under various conditions, in comparison with the optimal solution computed by the ILP approach. [ABSTRACT FROM AUTHOR]

Focusing on two rural cities in Minnesota, this paper analyses ways in which these communities have gone about providing information technology to their citizens. This paper will explain why one city has chosen to take an entrepreneurial approach to networking and the other city has chosen a more collaborative approach, promoting equal access for its citizens. Based on interviews, focus groups, and surveys in the two cities, we find that these divergent approaches are related to fundamental cultural differences in the two communities. One city seems to have a more pronounced reservoir of social capital, meaning that people in this community tend to be more trusting, have more cohesive social ties and are prone toward collaboration. Cooperation and social trust, particularly among community leaders, seem to have played large roles in triggering the development of a community electronic network. Moreover, we discover that political engagement and interpersonal trust among the citizenry in this city seem to be pivotal in sustaining and perpetuating the community endeavor. [Copyright &y& Elsevier]

Based on coupled networks, taking node load, capacity and load redistribution between two networks into consideration, we propose functionally identical coupled networks, which consist of two networks connected by interlinks. Functionally identical coupled networks are derived from the power grid of the United States, which consists of many independent grids. Many power transmission lines are planned to interconnect those grids and, therefore, the study of the robustness of functionally identical coupled networks becomes important. In this paper, we find that functionally identical coupled networks are more robust than single networks under random attack. By studying the effect of the broadness and average degree of the degree distribution on the robustness of the network, we find that a broader degree distribution and a higher average degree increase the robustness of functionally identical coupled networks under random failure. And SF-SF (two coupled scale-free networks) is more robust than ER-ER (two coupled random networks) or SF-ER (coupled random network and scale-free network). This research is useful to construct robust functionally identical coupled networks such as two cooperative power grids. [ABSTRACT FROM AUTHOR]

This paper presents data from the Program for the International Assessment of Adult Competencies with a focus on the interrelationships among health information seeking behavior (HISB), and health status or use of preventive health measures for U.S. adults both with and without a high school diploma. Key results of ordinal and binary logistic regression analyses indicated that, after controlling for demographic factors, (1) adults with a high school diploma use more text-based health information sources while adults without a high school diploma use more oral sources, (2) using the Internet as a source of health information is more strongly related to reporting excellent/very good health status than having a high school diploma, (3) those without a high school diploma who use the Internet report the largest increase in health status over any other health information source, and (4) for those with learning disability or vision problem, a high facility in reading English is an important predictor of whether the Internet is used as a health information source. The Internet appears to play a key role in both enhancing health status and enabling use of preventive measures for those with and without a high school diploma; although, individuals without a high school diploma who use the Internet for health information derive substantial benefit in health status. [ABSTRACT FROM AUTHOR]

The Water Data Exchange (WaDE) is a project initiated by the member states of the Western States Water Council (WSWC), in cooperation with the Western Governors' Association (WGA), to assist state water agencies when answering local, regional, and national water availability questions. WaDE provides requested information more easily, sustainably, and cost-effectively, by streamlining the publication of water planning, use, and allocation data for access by planners, policy makers, and the public. This paper presents the background of the WaDE project, how it was envisioned to function, the types of data it will provide, and why access to the information is important for water managers. The goals of WaDE include the establishment of a governance structure, documentation of the current state agency capabilities and methodologies, and the design of a common data format that targets water data products and/or water-quantity information. Many of these foundational products have been developed, such as governance workgroups, databases, web services code, and a prototype mapping application for centralized access. A major milestone, still underway, is the distribution and deployment of the databases and web services code within member states' information technology environments. Lastly, WaDE seeks to encourage the publication of other agency datasets using web services and standardized data formats. [ABSTRACT FROM AUTHOR]

Abstract: The shortcomings of Human Reliability Analysis (HRA) have been a topic of discussion for over two decades. Repeated attempts to address these limitations have resulted in over 50 HRA methods, and the HRA research community continues to develop new methods. However, there remains a gap between the methods developed by HRA researchers and those actually used by HRA practitioners. Bayesian Networks (BNs) have become an increasingly popular part of the risk and reliability analysis framework over the past decade. BNs provide a framework for addressing many of the shortcomings of HRA from a researcher perspective and from a practitioner perspective. Several research groups have developed advanced HRA methods based on BNs, but none of these methods has been adopted by HRA practitioners in the U.S. nuclear power industry or at the U.S. Nuclear Regulatory Commission. In this paper we bridge the gap between HRA research and HRA practice by building a BN version of the widely used SPAR-H method. We demonstrate how the SPAR-H BN can be used by HRA practitioners, and we also demonstrate how it can be modified to incorporate data and information from research to advance HRA practice. The SPAR-H BN can be used as a starting point for translating HRA research efforts and advances in scientific understanding into real, timely benefits for HRA practitioners. [Copyright &y& Elsevier]

Abstract: Recently practitioners are approaching spatial and environmental planning by adopting methods and tools drawn from Complexity Science. The strength of these methods is not only apparent in their systemic coherence but also in their capacity to consider a variety of components as a whole system. Given this background, the aim of this paper is to apply a methodology, tested for the Italian insular region of Sardinia, to an analysis of commuter accessibility in the United States through an indicator-based strategy. Spatial measures are applied to study the level of accessibility for commuters at the county level. The analysis provides us with an assessment of the accessibility for U.S. commuters and allows for the consideration of spatial planning objectives for U.S. counties. [Copyright &y& Elsevier]

Many technological networks can experience random and/or systematic failures in their components. More destructive situations can happen if the components have limited capacity, where the failure in one of them might lead to a cascade of failures in other components, and consequently break down the structure of the network. In this paper, the tolerance of cascaded failures was investigated in weighted networks. Three weighting strategies were considered including the betweenness centrality of the edges, the product of the degrees of the end nodes, and the product of their betweenness centralities. Then, the effect of the cascaded attack was investigated by considering the local weighted flow redistribution rule. The capacity of the edges was considered to be proportional to their initial weight distribution. The size of the survived part of the attacked network was determined in model networks as well as in a number of real-world networks including the power grid, the internet in the level of autonomous system, the railway network of Europe, and the United States airports network. We found that the networks in which the weight of each edge is the multiplication of the betweenness centrality of the end nodes had the best robustness against cascaded failures. In other words, the case where the load of the links is considered to be the product of the betweenness centrality of the end nodes is favored for the robustness of the network against cascaded failures. [ABSTRACT FROM AUTHOR]

Abstract: Power systems are the basic support of modern infrastructures and protecting them from random failures or intentional attacks is an active topic of research in safety science. This paper is motivated by the following two related problems about cascading failures on power grids: efficient edge attack strategies and lower cost protections on edges. Applying the recent cascading model by adopting a local load redistribution rule, where the initial load of an edge ij is (k i k j ) θ with k i and k j being the degrees of the nodes connected by the edge, we investigate the performance of the power grid of the western United States subject to three intentional attacks. Simulation results show that the effects of different attacks for the network robustness against cascading failures have close relations with the tunable parameter θ. Particularly, the attack on the edges with the lower load in the case of θ <1.4 can result in larger cascading failures than the one on the edges with the higher load. In addition, compared with the other two attacks, a new attack, i.e., removing the edges with the smallest proportion between the total capacities of the neighboring edges of and the capacity of the attacked edge, usually are prone to trigger cascading failures over the US power grid. Our findings will be not only helpful to protect the key edges selected effectively to avoid cascading-failure-induced disasters, but also useful in the design of high-robustness and low-cost infrastructure networks. [Copyright &y& Elsevier]

Abstract: Purpose: To evaluate current applications of e-learning in radiology. Material and methods: A Medline search was performed using PubMed (National Library of Medicine, Bethesda, MD) for publications discussing the applications of e-learning in radiology. The search strategy employed a single combination of the following terms: (1) e-learning, and (2) education and (3) radiology. This review was limited to human studies and to English-language literature. We reviewed all the titles and subsequent the abstract of 29 articles that appeared pertinent. Additional articles were identified by reviewing the reference lists of relevant papers. Finally, the full text of 38 selected articles was reviewed. Results: Literature data shows that with the constant development of technology and global spread of computer networks, in particular of the Internet, the integration of multimedia and interactivity introduced into electronic publishing has allowed the creation of multimedia applications that provide valuable support for medical teaching and continuing medical education, specifically for radiology. Such technologies are valuable tools for collaboration, interactivity, simulation, and self-testing. However, not everything on the World Wide Web is useful, accurate, or beneficial: the quality and veracity of medical information on the World Wide Web is variable and much time can be wasted as many websites do not meet basic publication standards. Conclusion: E-learning will become an important source of education in radiology. [Copyright &y& Elsevier]

The opportunity that the Internet represents for children is undeniable. The increasing amount of children's personal data collected online raises an issue balance: how to protect children's privacy without impeding the development of children's online opportunities. Businesses collect children's personal data in order to profile and target them. Aware of the risks such practices represent for children's data protection, the US Congress has legislated the Child Online Privacy Protection Act (the so-called 'COPPA') which became effective in April 2000. In Europe, the collection and use of personal data is covered by the 1995/46 European Directive which has the fundamental aim of protecting individual privacy. The Directive does not, however, distinguish between data subjects who are adults and those who are children: it provides no specific protection for children's privacy.This paper considers the different approaches adopted in the USA and in Europe with regard to children's online data protection. In parallel, it appears that soft law is used as a new tool to regulate children's privacy. Particular attention will be paid to soft law adopted in the UK and in France. [ABSTRACT FROM AUTHOR]

Abstract: Interoperability has been identified as a major issue to be addressed by every egovernment initiatives. In order to tackle this issue, the egovernment agencies have developed tools to facilitate the interchange of information between departments when providing public services to citizens and businesses through internet. This paper surveys how the egovernment agencies in Europe and the United States have developed tools such as interoperability frameworks and enterprise architectures. It covers specifically how the semantic technologies and standards have been incorporated into the interoperability frameworks. The incorporation is a sign of maturity, because interoperability is to cover not only technical aspects, but also semantic and, in the end, organisational aspects. [Copyright &y& Elsevier]

There is a very clear need for the expanded application of information technology (IT) in healthcare. Clinical workflow still depends largely on manual, paper-based medical record systems in an activity that is economically inefficient and produces significant variances in medical outcomes. IT spend currently represents around 1.3% of total healthcare spend on average. As shown in Table ES.1, this equates to a global market for healthcare information products and services of $47.5 billion in 2002. The value is forecast to grow by an average of 9.4% per annum to reach $74.5 billion in 2007. As may be expected, the US dominates the market, taking just under 50% of the 2002 global revenues, but will marginally fall back to take under 49% of the total by 2007. During this period, the US market is forecast to grow by an average of 8.9% per annum from $23.7 billion in 2002, to $48.7 billion in 2007. In contrast, the European market will grow at an average of 10.1% per annum, Japan by 8.5% per annum, but the rest of the world, which is currently under-provided with IT, by 10.5% per annum. Table ES.1. World healthcare IT market by region, 2002 and 2007. Year 2002 2007 Region Revenues ($ billion) Total (%) Revenues ($ billion) Total (%) Average per annum growth (%) Source: Author's estimates. US 23.7 49.9 36.3 48.7 8.9 Europe 14.3 30.1 23.2 31.1 10.1 Japan 3.9 8.2 5.9 7.9 8.5 Rest of the world 5.6 11.8 9.2 12.4 10.5 World total 47.5 100.0 74.6 100.0 9.4 [ABSTRACT FROM AUTHOR]

Privacy is becoming a major issue in ad hoc networks. In this paper, using pseudonimity for achieving communication anonymity in networks that apply geographic-routing algorithms is explored. An Anonymous Receiver-Contention POsitioning (ARCPO) routing algorithm is proposed. Node identities (IDs) are kept anonymous. Pseudonyms, i.e., the positions of destinations, are used for data-packet delivery. The anonymity for a destination relies on the difficulty of matching its position to its ID by any observer. Position servers that provide node position information act as trusted third parties and handle identity management. Node mobility makes the use of the pseudonym momentary, and therefore can further improve privacy. The anonymity for the source and intermediate nodes in the path is also achieved because they are not required to reveal any identity information. A receiver-contention mechanism is proposed so that a next hop can be generated without local position information exchange, which otherwise may lead to severe privacy degradation. Analysis and simulation show that while ARCPO guarantees anonymous communication in ad hoc networks, its routing performance degrades moderately compared with other position routing algorithms. [ABSTRACT FROM AUTHOR]

In this paper, the authors propose a node-cooperative automatic repeat request (ARQ) scheme for wireless ad hoc networks, which is suitable for mobile wireless channels with high and correlated frame-error profile. An analytical model based on a two-state Markovian process is proposed to describe the behavior of the proposed retransmission scheme and to obtain its throughput, average delay, and delay jitter. The results of Monte Carlo simulations are included to demonstrate the efficacy of the proposed scheme and to verify the accuracy of the analytical models. Results show that a cooperation among a small number of nodes can significantly improve the performance of the retransmission process in terms of throughput, average delay, and delay jitter by reducing the average duration of retransmission trials. [ABSTRACT FROM AUTHOR]

During the last several years, the interest in wireless networking has grown significantly due to the availability of many wireless products, such as cell phones, wireless enabled mice, keyboards, modems, and many other products. Bluetooth-enabled cell phones, personal digital assistance (PDAs), and laptops are becoming common. Wireless fidelity (Wi-Fi) products are growing at a rapid rate. Several companies have already started developing WiMax products. The reason for the rapid growth of wireless technology is that it provides the users with additional convenience over the wired technology. General Motors Corporation introduced a Bluetooth network in its 2003 Saab 9–3 model car. Having a wireless personal area network (WPAN) in a vehicle will allow the driver to control the various operations within the vehicle without taking his hands off the steering wheel. For example, the driver will be able to make a phone call through a Bluetooth-enabled headset and a Bluetooth-enabled cell phone using voice-activated dialing features. If the Bluetooth network is connected to the vehicle's wired network through an appropriate gateway device, then the driver will be able to control the lights, windshield wipers, air flow, heat, and various other features of the vehicle through a Bluetooth-enabled headset and voice-activated features. An in-vehicle WPAN will also allow the users to use their PDAs as electronic car keys. Though an in-vehicle WPAN can provide the users with many convenient features, it can also make the vehicle system vulnerable to many types of security attacks unless it is properly designed. In this paper, the authors present a technique for building an in-vehicle secure WPAN (SWPAN). The technique is user friendly and easy to use. [ABSTRACT FROM AUTHOR]

In this paper, a new cross-layer communication protocol for vehicular Internet access along highways is introduced. The objective of the new Controlled Vehicular Internet Access (CVIA) protocol is to increase the end-to-end throughput while achieving fairness in bandwidth usage between road segments. To achieve this goal, the CVIA protocol eliminates contention in relaying packets over long distances. CVIA creates single-hop vehicle clusters and mitigates the hidden node problem by dividing the road into segments and controlling the active time of each segment. Using an analytical throughput estimation model, the protocol parameters are flue-tuned to provide fairness among road segments. Simulation results confirm that the proposed CVIA protocol provides higher throughput and better fairness in multihop data delivery in vehicular networks when compared with purely IEEE 802.11-based protocols. [ABSTRACT FROM AUTHOR]

Energy constraints have a significant impact on the design and operation of wireless sensor networks. This paper investigates the base station (BS) selection (or anycast) problem in wireless sensor networks. A wireless sensor network having multiple BSs (data sink nodes) is considered. Each source node must send all its locally generated data to only one of the BSs. To maximize network lifetime, it is essential to optimally match each source node to a particular BS and find an optimal routing solution. A polynomial time heuristic is proposed for optimal BS selection and anycast via a sequential fixing procedure. Through extensive simulation results, it is shown that this algorithm has excellent performance behavior and provides a near-optimal solution. [ABSTRACT FROM AUTHOR]

This paper examines the problem of quality-of-service group communications in a heterogeneous network, which consists of multiple mobile ad hoc networks attached to the backbone Internet. A heuristic multicast algorithm named delay and delay variation multicast algorithm (DDVMA) is proposed. DDVMA is designed for solving the delay- and delay-variation-bounded multicast tree problem, which has been proved to be NP-complete. It can find a multicast tree satisfying the multicast end-to-end delay constraint and minimizing the multicast delay variation. Two concepts, which can help the DDVMA achieve better performance in terms of multicast delay variation than the delay and delay variation constraint algorithm that is known to be the most efficient so far, are proposed, namely, 1) the proprietary second shortest path and 2) the partially proprietary second shortest path. An analysis is given to show the correctness of DDVMA, and simulations are conducted to demonstrate the performance improvement of DDVMA in terms of multicast delay variation. It is also shown that the strategy employed by DDVMA is also applicable to handling the mobility of mobile hosts in a heterogeneous network. [ABSTRACT FROM AUTHOR]

A network of sensors can be used to obtain state-based data from the area in which they are deployed. To reduce costs, the data, sent via intermediate sensors to a sink, are often aggregated (or compressed). This compression is done by a subset of the sensors called ‘aggregators.’ Inasmuch as sensors are usually equipped with small and unreplenishable energy reserves, a critical issue is to strategically deploy an appropriate number of aggregators so as to minimize the amount of energy consumed by transporting and aggregating the data. In this paper, the authors first study single-level aggregation and propose an Energy-Efficient Protocol for Aggregator Selection (EPAS) protocol. Then, they generalize it to an aggregation hierarchy and extend EPAS to Hierarchical EPAS. The optimal number of aggregators with generalized compression and power-consumption models was derived, and fully distributed algorithms for aggregator selection were presented. Simulation results show that the algorithms significantly reduce the energy consumption for data collection in wireless sensor networks. Moreover, the algorithms do not rely on particular routing protocols and are thus applicable to a broad spectrum of application environments. [ABSTRACT FROM AUTHOR]

One of the main characteristics of wireless ad hoc networks is their node-centric broadcast nature of communication, leading to interferences and spatial contention between adjacent wireless links. Due to such interferences, pessimistic concerns have been recently raised with respect to the decreasing network capacity in wireless ad hoc networks when the number of nodes scales to several orders of magnitude higher. Such studies assume uniformly distributed nodes in the network and randomized traffic patterns. In this paper, we argue that in all cases of end-to-end data communications—including one-to-k unicast and multicast data dissemination as well as/c-to-one data aggregation—the maximum achievable end-to-end data throughput (measured on the sources) heavily depends on the strategy of arranging the topology of transmission between sources and destinations, as well as possible per-node operations such as coding. An optimal strategy achieves better end-to-end throughput than an arbitrary one. We present theoretical studies and critical insights with respect to how these strategies may be designed so that end-to-end throughput may be increased. After all, under all circumstances—in either a lightly loaded or a congested network—increasing end-to-end throughput from its baseline is always beneficial to applications using ad hoc networks to communicate. [ABSTRACT FROM AUTHOR]

Providing adequate computing lab support for Management Information Systems (MIS) and Computer Science (CS) programs is a perennial challenge for most academic institutions in the US and abroad. Factors, such as lack of physical space, budgetary constraints, conflicting needs of different courses, and rapid obsolescence of computing technology, precipitate this challenge. While introductory computing courses can be adequately supported through general labs, advanced computing courses typically require dedicated labs. Normally, however, even a dedicated lab must simultaneously support multiple courses with diverse support requirements. Consequently, in designing dedicated computing labs, versatility and flexibility of the lab must be the prime consideration. Drawing on the insights gained from developing a dedicated lab, the authors present a model for developing a versatile, flexible lab to support computer network courses. The proposed model entails a modular design approach which offers ease of management, configuration and upgrading of the lab by decoupling the lab functions into layers. The layered design divides the lab into four management layers: (1) wiring layer, (2) networking layer, (3) server systems layer, and (4) support procedures layer. Each layer offers a versatile and configurable design and serves as a foundation for the next higher layer. Wiring layer minimizes the wire configuration efforts and enhances wiring flexibility by utilizing patch panels at the computer desks and the racks housing networking devices, and sufficient underground wiring between desks and racks. The underground wiring allows for network, telephone and serial cable connections as needed. Network layer builds LANs, subnets and internets with minimal configuration effort through a careful arrangement of network hubs, switches, routers, and firewalls. The network layer distinguishes between permanent networks needed in the lab, called pre-configured networks, and the networks that are assembled and disassembled by the students, called configurable networks. The network address allocation schemes for different types of network experiments are also discussed. Server systems layer covers two categories of servers: pre-configured servers and configurable servers. Pre-configured servers, such as DNS and file servers, are production servers that support network experiments. Configurable servers are hardware platforms that can be configured as needed according to experimental needs. The last layer, procedural layer, provides policies, guidelines and operational procedures that are needed for proper utilization of the lab space and the equipment. The paper also illustrates the application of the proposed model through the design and configuration of the computing lab for network courses underlying this case study. [ABSTRACT FROM PUBLISHER]

Several information systems' and computer-mediated communication studies in the literature measure user's perceptions of email. The user's perceptions of email were used to develop and validate the Technology Acceptance Model (TAM). While a user's perceptions of email play an important role in literature, very few studies have focused solely on developing a construct for measuring these perceptions. In this paper, we develop a construct to measure an individual's perceptions of email as a medium for electronic communication in organizations. Using a survey of management and non management employees in Northeastern US, we empirically test our theoretical construct. The results of our research indicate that an individual's perceptions of email are a multidimensional construct with two dimensions: the individual level dimension and the organizational level. At an individual level, a person's perceptions may be impacted by email's role in improving productivity, supporting team work, and providing global reach. At an organizational level a person's perceptions may be impacted by email's role in making an organization vulnerable to viruses, exposing proprietary information, and/or encouraging unprofessional and illegal behavior. [ABSTRACT FROM AUTHOR]

As community technology and community-building initiatives move toward greater synergy, there is a great deal to be learned regarding how they can be mutually supportive, rather than mutually exclusive. This article sheds light on the possibilities inhered at this nexus. The project that constitutes the basis for this paper is the Camfield Estates-MIT Creating Community Connections Project, an ongoing effort at Camfield Estates, a predominantly African-American, low- to moderate-income housing development. As part of this project, we worked with residents to establish a technological infrastructure by offering every family a new computer, software, high-speed Internet connection, comprehensive courses, and a web-based community-building system, the Creating Community Connections (C3) System, that I codesigned with residents. This article presents an overview of the Camfield Estates-MIT project, theoretical framework developed in relation to this work, research design and methodology, project methodology and timeline, and early results. It concludes with a set of recommendations for the community technology and community-building movements. [ABSTRACT FROM AUTHOR]

A growing movement toward public access to the federal government via the Internet has created increased interest in establishing network communications and information services, especially among national officeholders. However, little empirical study of the use and users of such services exists to guide their efforts This paper reports results of a two-part study of the use and users of US Representative Sam Coppersmith's (D - Arizona 1) Gopher and distribution list services during the first quarter of 1994. The first part analyzes Gopher usage data gathered during the study period. The second part detials with a user survey distributed to fifty-seven Gopher server guest registrants and eighty listserv subscribers just after the end of the study period. The research shows that (1) use of the Gopher subdirectory dwarfs that of the listserv, (2) services like Coppersmith's should provide basic information, as well as unique and timely information and issue position statements, (3) assessment of such services is methodologically challenging, and (4) Coppersmith's services are effective information media that promote observability of distant officeholders, a function that helps promote increased participation in government. [ABSTRACT FROM AUTHOR]

During the 1994 spring semester, twelve students, enrolled in Columbia University's graduate program in public policy and administration and explored the new phenomenon of civic networking for a workshop in applied public policy analysis. Each workshop is required to be sponsored by a governmental client, which in this case was the US National Commission on Libraries and Information Science. The commission was interested in ascertaining the range of activities sponsored by the networks and in determining their involvement or lack of involvement with local public libraries. Participating in this project were representatives of twenty-four civic networks, who answered telephone queries covering a range of topics dealing with network services, users, goals, funding, governance, technical design, social benefits, government information provision, evaluation, and definition. This paper summarizes the findings of the students' investigation. [ABSTRACT FROM AUTHOR]

A rapidly expanding number of organizations have begun to use high-performance, completely digital networks, like the Internet, to coordinate activities and to develop products and services that serve very wide geographic areas. Now, primarily as a result of the Clinton Administration's National Information Infrastructure initiative, the entire nation has begun to buzz with talk of the whys, wherefores, and how-tos of making this way to doing business the rule rather than the exception of twenty-first-century life and enterprise. This paper surveys the politics and economics of the contemporary networking scene, and presents four general stratgies for making progress in the current climate of great change and uncertainty. [ABSTRACT FROM AUTHOR]

Software-driven hardware configurations account for the majority of modern safety-critical complex systems. The often costly failures of such systems can be attributed to software specific, hardware specific, or software/hardware interaction failures. The understanding of how failures propagate in such complex systems might provide critical information to designers, because, while a software component may not fail in terms of loss of function, a software operational state can cause an associated hardware failure. The least expensive phase of the product life cycle to address failures is during the design stage. This research presents a means to evaluate how a combined software/hardware system behaves and how such failures propagate to result in potential failures downstream, during the conceptual design stage. In particular, this paper proposes the use of high-level system modeling and model-based reasoning approaches to model failure propagation in combined software-hardware systems, introducing the Function-Failure Identification and Propagation (FFIP) analysis framework to help formalize the design of safety-critical systems. The fact that the hardware and software designers do not share the same background, knowledge, methods, or language contributes significantly to software/hardware interaction failures. A high-level systems analysis method, such as FFIP, is geared toward the unification of language and modeling concepts and may help to more seamlessly bridge such a gap. The technique is applied to the design of the Reaction Control System Jet Selection of the NASA space shuttle to evaluate failure propagation within the Reaction Control System Jet selection, specifically for the redundancy management system. The paper concludes with the extensions and mappings to the software domain that are required for a truly integrated methodology. [ABSTRACT FROM AUTHOR]

Previous analytical work [16], [17] on the resilience of P2P networks has been restricted to disconnection arising from simultaneous failure of all neighbors in routing tables of participating users. In this paper, we focus on a different technique for maintaining consistent graphs—Chord's successor sets and periodic stabilizations—under both static and dynamic node failure. We derive closed-form models for the probability that Chord remains connected under both types of node failure and show the effect of using different stabilization interval lengths (i.e., exponential, uniform, and constant) on the probability of partitioning in Chord. [ABSTRACT FROM AUTHOR]