9065684
NodeWiz: peer-to-peer resource discovery for grids
Efficient resource discovery based on dynamic attributes such as CPU utilization and available bandwidth is a crucial problem in the deployment of computing grids. Existing solutions are either centralized or unable to answer advanced resource queries (e.g., range queries) efficiently. We present the design of NodeWiz, a grid information service (CIS) that allows multi-attribute range queries to be performed efficiently in a distributed manner. This is obtained by aggregating the directory services of individual organizations in a peer-to-peer information service.
10289717
Estimating network proximity and latency
Network proximity and latency estimation is an important component in discovering and locating services and applications. With the growing number of services and service providers in the large-scale Internet, accurately estimating network proximity/latency with minimal probing overhead becomes essential for scalable deployment. Although there exist a number of network distance estimation schemes, they either rely on extensive infrastructure support, require the IP address of the potential targets, falsely cluster distant nodes, or perform poorly with even few measurement errors. We propose Netvigator, a scalable network proximity and latency estimation tool that uses information obtained from probing a small number of landmark nodes and intermediate routers (termed milestones) that are discovered en route to the landmarks, to identify the closest nodes. With very little additional probing overhead, Netvigator uses distance information to the milestones to accurately locate the closest nodes. We developed a Netvigator prototype and report our performance evaluation on PlanetLab and in the intranet of a large enterprise. Netvigator is a running service on PlanetLab as a part of HP Labs' S3 (Scalable Sensing Service).
32056587
Improving aggregated channel performance through decentralized channel monitoring
Aggregating low-speed WAN links into a higher-speed logical link promises to improve data-transfer rates to collaborating communities of wireless mobile multihomed devices. Such bandwidth aggregation systems must adapt to link dynamics as the number of links and the channel conditions vary with time due to mobility, power dissipation, and channel interference. A monitoring architecture that accurately measures the link dynamics and promptly feeds this information to the system is vital to realize significant bandwidth aggregation performance gains. In this paper we present various architectural design alternatives for such a monitoring system, and evaluate them using both analysis and simulation. We show that a properly-designed monitoring system can accurately measure and quickly respond to changes in communication link performance while minimizing the control overhead.
933849
Scalability study of the ad hoc on-demand distance vector routing protocol
As mobile networking continues to experience increasing popularity, the need to connect large numbers of wireless devices will become more prevalent. Many recent proposals for ad hoc routing have certain characteristics that may limit their scalability to large networks. This paper examines five different combinations of modifications that may be incorporated into virtually any on-demand protocol in order to improve its scalability. The scalability of current on-demand routing protocols is evaluated through the selection of a representative from this class of protocols. The performance of the un-modified on-demand protocol is compared against that of it combined with each of the scalability modifications. Each scheme's behavior is analyzed in networks as large as 10,000 nodes through detailed simulation. Based on the observations, conclusions are drawn as to the expected scalability improvement that can be achieved by each modification.
6659898
On-Demand Multicast Routing Protocol in Multihop Wireless Mobile Networks
An ad hoc network is a dynamically reconfigurable wireless network with no fixed infrastructure or central administration. Each host is mobile and must act as a router. Routing and multicasting protocols in ad hoc networks are faced with the challenge of delivering data to destinations through multihop routes in the presence of node movements and topology changes. This paper presents the On-Demand Multicast Routing Protocol (ODMRP) for wireless mobile ad hoc networks. ODMRP is a mesh-based, rather than a conventional tree-based, multicast scheme and uses a forwarding group concept; only a subset of nodes forwards the multicast packets via scoped flooding. It applies on-demand procedures to dynamically build routes and maintain multicast group membership. ODMRP is well suited for ad hoc wireless networks with mobile hosts where bandwidth is limited, topology changes frequently, and power is constrained. We evaluate ODMRP performance with other multicast protocols proposed for ad hoc networks via extensive and detailed simulation.
15064150
Caching strategies in transcoding-enabled proxy systems for streaming media distribution networks
With the wide availability of high-speed network access, we are experiencing high quality streaming media delivery over the Internet. The emergence of ubiquitous computing enables mobile users to access the Internet with their laptops, PDAs, or even cell phones. When nomadic users connect to the network via wireless links or phone lines, high quality video transfer can be problematic due to long delay or size mismatch between the application display and the screen. Our proposed solution to this problem is to enable network proxies with the transcoding capability, and hence provide different, appropriate video quality to different network environment. The proxies in our transcoding-enabled caching (TeC) system perform transcoding as well as caching for efficient rich media delivery to heterogeneous network users. This design choice allows us to perform content adaptation at the network edges. We propose three different TeC caching strategies. We describe each algorithm and discuss its merits and shortcomings. We also study how the user access pattern affects the performance of TeC caching algorithms and compare them with other approaches. We evaluate TeC performance by conducting two types of simulation. Our first experiment uses synthesized traces while the other uses real traces derived from an enterprise media server logs. The results indicate that compared with the traditional network caches, with marginal transcoding load, TeC improves the cache effectiveness, decreases the user-perceived latency, and reduces the traffic between the proxy and the content origin server.
12791194
Accelerating Key Establishment Protocols for Mobile Communication
Mobile communication is more vulnerable to security attacks such as interception and unauthorized access than fixed network communication. To overcome these problems, many protocols have been proposed to provide a secure channel between a mobile station and a base station. However, the public-key based protocols are not fully utilized due to the poor computing power and the small battery capacity of a mobile station. 
 
In this paper, we propose some techniques accelerating public-key based key establishment protocols between a mobile station and a base station. The proposed techniques enable a mobile station to borrow computing power from a base station without revealing its secret information. The proposed schemes accelerate the previous protocols up to five times and reduce the amount of power consumption of a mobile station. 
 
The proposed schemes use SASC (Server-Aided Secret Computation) protocols that are used for smart cards. Our insight is that the unbalanced property in computing power of the mobile communication is similar to that of the smart card system. The acceleration degrees of the proposed schemes are quite different from one another according to the used SASC protocols. In this paper, we analyze the acceleration factors of the proposed schemes and compare them with one another. The analysis shows that one of the approach presents outstanding performance among them.
14700721
Designing Semistructured Databases: A Conceptual Approach
Semistructured data has become prevalent with the growth of the Internet. The data is usually stored in a database system or in a specialized repository. Many information providers have presented their databases on the web as semistructured data, while others are developing repositories for new applications. Designing a "good" semistructured database is important to prevent data redundancy and updating anomalies. In this paper, we propose a conceptual approach to design semistructured databases. A conceptual layer based on the Entity-Relationship model is used to remove redundancies at the semantic level. An algorithm to map an ER diagram involving composite attributes weak entity types, recursive, n-ary and ISA relationship sets, and aggregations to a semistructured schema graph (S3-Graph) is also given.
206586460
Context Awarable Self-configuration System for Distributed Resource Management
Today's system administrator is forced to perform individual configuration and maintenance tasks (i.e. installation, reconfiguration, update) on numerous systems, in various formats. These tasks are time-consuming and labor intensive. Several research projects have attempted to resolve these issues with the development of an integrated, centralized management system. However, many tasks are still left to the system administrator for manual handling. A customized configuration system that reflects comprehensive context has not yet been fully realized. This paper proposes a context aware self-configuration system by employing multi-agents to collectively gather contextual information based on the system resources and user's system usage patterns. This proposed system, then analyzes the collected information and performs automatic configuration as and when required. This system will allow not only enable automation of the previously manual tasks, but also allow, in effect, a more customized configuration.
30489867
Intelligent Multimedia Service System Based on Context Awareness in Smart Home
According to the rapid change of a computing environment, it is coming an age of ubiquitous computing that we can make use of information service at any time and anywhere as the paradigm of digital convergence such as broadcasting, communication, and appliances. Consequently, Smart Home environment is constructed in the house. Various services such as security/automation, health monitoring, medical examination and treatment, entertainment, education, and e-business are realized at home. Both affective, systematic managements and services that correspond with the above environment are required inmultimedia services as well. In this paper, we propose a Intelligent Multimedia Service System(IMSS) based on context awareness in Smart Home which provides multimedia interoperability among incompatible multimedia play devices, intelligently processes context awareness information, transparent, and provides safe services.
18035365
A Web Service Approach to Universal Accessibility in Collaboration Services
The enormous growth in wireless communications and miniaturized handheld devices in the last few years, have given rise to a vast range of new services, for heterogeneous user environments. In this paper, we investigate the nature of designing distributed services that accommodate pervasive devices. We introduce Universal Accessible Web service architecture, CAROUSEL Web service. We present our collaborative Web services model linked with an event brokering service, NaradaBrokering. We discuss how a rich synchronous and asynchronous collaboration environment can support virtual communications while being built on top of a Web service infrastructure, based on industry standard portal technologies such as XML, Apache’s Jetspeed, and WSDL. The linkage of the event brokering system with a Web service based architecture is one of the critical design issues in message-based collaborative application. We also describe the approach to universal access mechanisms in our collaborative Web service model. Also included is a discussion of the prototype collaborative SVG (Scalable Vector Graphics) browser that we developed as a Web service.