Location awareness in unstructured peer-to-peer systems

Peer-to-peer (P2P) computing has emerged as a popular model aiming at further utilizing Internet information and resources. However, the mechanism of peers randomly choosing logical neighbors without any knowledge about underlying physical topology can cause a serious topology mismatch between the P2P overlay network and the physical underlying network. The topology mismatch problem brings great stress in the Internet infrastructure. It greatly limits the performance gain from various search or routing techniques. Meanwhile, due to the inefficient overlay topology, the flooding-based search mechanisms cause a large volume of unnecessary traffic. Aiming at alleviating the mismatching problem and reducing the unnecessary traffic, we propose a location-aware topology matching (LTM) technique. LTM builds an efficient overlay by disconnecting slow connections and choosing physically closer nodes as logical neighbors while still retaining the search scope and reducing response time for queries. LTM is scalable and completely distributed in the sense that it does not require any global knowledge of the whole overlay network. The effectiveness of LTM is demonstrated through simulation studies.     

Connecting Design with Code

Jon Bentley wrote his thesis on divide-and-conquer algorithms and came to greatly admire C.A.R. Hoare's original quicksort algorithm. Yet for years, Bentley "tiptoed around its innermost loop" because he didn't understand it (Beautiful Code, O'Reilly, 2007). It was only after he implemented his own quicksort based on an elegant partitioning scheme for programming Pearls (Addison-Wesley, 1999) that he truly understood the reason for that inner loop. He also trimmed the original bulkier algorithm to a mere dozen tight lines of code. Code clutter and unnecessary complexity can obscure a design. However, connecting design decisions to code won't happen unless developers embrace the practice of writing code as if expressing design intent matters.     

网络安全态势感知技术与系统

现如今网络规模正在逐渐壮大,网络结构也变得越来越复杂,各种网络病毒以及黑客攻击成为了普遍现象,过去的网络安全管理技术只是依靠防火墙、各种杀毒软件等单一的被动安全保护进行网络安全管理,在当今这个时代里早已无法满足网络安全的基本需求,基于这种原因,更加迫切的需要一种新的网络安全技术来进行预防和监控。而网络安全态势感知技术则很好的满足了这些需求,它可以对某段时间内的网络进行全方位监控和预警。     

Connecting the physical world with pervasive networks

This article addresses the challenges and opportunities of instrumenting the physical world with pervasive networks of sensor-rich, embedded computation. The authors present a taxonomy of emerging systems and outline the enabling technological developments.     

Social presence and group attraction: exploring the effects of awareness systems in the home

This paper describes an experimental assessment of affective user benefits that may result from adding peripheral awareness information while remote friends share an activity in a home environment. The experiment has shown that providing awareness information increases the social presence and the group attraction felt by individuals towards remote partners.     

利用USB接口接入局域网的设计

提出了一种多台计算机可以方便地使用各自的USB接口接入局域网的方案.     

Oscillation family in weakly coupled identical systems

Consideration was given to an autonomous model with weakly coupled identical subsystems. Existence of a family of periodic solutions which is similar to the family in a subsystem was established. A scenario of bifurcations of the characteristic exponents was given, and the stabilization problem was solved. An example was given.     

Globally exponentially attractive sets of the family of Lorenz systems

In this paper, the concept of globally exponentially attractive set is proposed and used to consider the ultimate bounds of the family of Lorenz systems with varying parameters. Explicit estimations of the ultimate bounds are derived. The results presented in this paper contain all the existing results as special cases. In particular, the critical cases, b→ 1^＋ and a→0^＋, for which the previous methods failed, have been solved using a unified formula.     

Connecting the home with a phone line network chip set

In addition to shared Internet access for PCs, the home network will connect to every consumer electronic device. To make this possible, we must consider robust system requirements, home phone line standards, costs, and implementation of a supporting iline10 chip set     

Simulating collaborative systems by means of awareness of interaction among intelligent agents

New specific collaboration models for distributive systems are needed for enabling effective collaboration processes between users of these dynamic environments. However, collaboration in distributive systems depends on several elements such as a negotiation mechanism, a load-balancing strategy, a mutual exclusion mechanism, and a learning strategy. Each of these elements should be analyzed separately in terms of efficiency and effectiveness in order to improve these two features in the global collaborative system. This paper presents a multi-agent based simulation tool and a simulation methodology used to evaluate the efficiency and effectiveness of a collaborative system by analyzing both the global system of each of the strategies or mechanisms involved in the system. Intelligent agents used in the simulation make use of the concept of awareness of interaction for quantifying the degree, nature and quality of the interaction between the agents.     

Representing situation awareness in collaborative systems: A case study in the energy distribution domain

The concept of distributed situation awareness (DSA) is currently receiving increasing attention from the human factors community. This article investigates DSA in a collaborative real-world industrial setting by discussing the results derived from a recent naturalistic study undertaken within the UK energy distribution domain. The results describe the DSA-related information used by the networks of agents involved in the scenarios analysed, the sharing of this information between the agents and the salience of different information elements used. Thus, the structure, quality and content of each network's DSA is discussed, along with the implications for DSA theory. The findings reinforce the notion that when viewing situation awareness (SA) in collaborative systems, it is useful to focus on the coordinated behaviour of the system itself, rather than on the individual as the unit of analysis and suggest that the findings from such assessments can potentially be used to inform system, procedure and training design. SA is a critical commodity for teams working in industrial systems and systems, procedures and training programmes should be designed to facilitate efficient system SA acquisition and maintenance. This article presents approaches for describing and understanding SA during real-world collaborative tasks, the outputs from which can potentially be used to inform system, training programmes and procedure design.     

Representing situation awareness in collaborative systems: a case study in the energy distribution domain

The concept of distributed situation awareness (DSA) is currently receiving increasing attention from the human factors community. This article investigates DSA in a collaborative real-world industrial setting by discussing the results derived from a recent naturalistic study undertaken within the UK energy distribution domain. The results describe the DSA-related information used by the networks of agents involved in the scenarios analysed, the sharing of this information between the agents and the salience of different information elements used. Thus, the structure, quality and content of each network's DSA is discussed, along with the implications for DSA theory. The findings reinforce the notion that when viewing situation awareness (SA) in collaborative systems, it is useful to focus on the coordinated behaviour of the system itself, rather than on the individual as the unit of analysis and suggest that the findings from such assessments can potentially be used to inform system, procedure and training design. SA is a critical commodity for teams working in industrial systems and systems, procedures and training programmes should be designed to facilitate efficient system SA acquisition and maintenance. This article presents approaches for describing and understanding SA during real-world collaborative tasks, the outputs from which can potentially be used to inform system, training programmes and procedure design.     

Absolute stability of an interval family of nonlinear dynamic systems with nonlinear feedback

Based on the direct Lyapunov method, the sufficient conditions of the absolute stability of an interval family of Lurie nonlinear dynamic systems are obtained. Checking of these conditions requires small computational costs.     

Enhancing DSR maintenance with power awareness

A power-aware route maintenance protocol for Mobile Ad Hoc Networks (MANETs) is introduced. Termed Dynamic Path Switching (DPS), the new protocol puts an overloaded node to sleep before a route link breaks because that node runs out of energy, and brings other suitable nodes into play instead. When the battery charge of a node reaches a stated level, the node can advance a request to change to a sleep state for a while. The request is honoured unless survival of some path rests on the forwarding activity of that very node. All nodes are assumed to be collaborative. The DPS protocol is fully backward compatible, as it can be implemented within existing routing protocols such as Dynamic Source Routing (DSR). The new protocol has been extensively simulated with the established network simulator NS2. The findings indicate a much improved power awareness of the updated routing protocol with respect to the unadorned one. Power saving is particularly effective during long-lived sessions.     

A family history of Honeywell's large-scale computer systems

Honeywell Information Systems marketed a broad line of large computer hardware and software, whose heritage goes back to the early 1960s. The authors of this article played key roles in the evolution of today's software (King) and hardware (Shelly)