Showing papers on "Service (systems architecture) published in 2003"

Anonymous Usage of Location-Based Services Through Spatial and Temporal Cloaking

Abstract: Advances in sensing and tracking technology enable location-based applications but they also create significant privacy risks. Anonymity can provide a high degree of privacy, save service users from dealing with service providers’ privacy policies, and reduce the service providers’ requirements for safeguarding private information. However, guaranteeing anonymous usage of location-based services requires that the precise location information transmitted by a user cannot be easily used to re-identify the subject. This paper presents a middleware architecture and algorithms that can be used by a centralized location broker service. The adaptive algorithms adjust the resolution of location information along spatial or temporal dimensions to meet specified anonymity constraints based on the entities who may be using location services within a given area. Using a model based on automotive traffic counts and cartographic material, we estimate the realistically expected spatial resolution for different anonymity constraints. The median resolution generated by our algorithms is 125 meters. Thus, anonymous location-based requests for urban areas would have the same accuracy currently needed for E-911 services; this would provide sufficient resolution for wayfinding, automated bus routing services and similar location-dependent services.

Service-oriented computing: concepts, characteristics and directions

Abstract: Service-oriented computing (SOC) is the computing paradigm that utilizes services as fundamental elements for developing applications/solutions. To build the service model, SOC relies on the service oriented architecture (SOA), which is a way of reorganizing software applications and infrastructure into a set of interacting services. However, the basic SOA does not address overarching concerns such as management, service orchestration, service transaction management and coordination, security, and other concerns that apply to all components in a service architecture. In this paper we introduce an extended service oriented architecture that provides separate tiers for composing and coordinating services and for managing services in an open marketplace by employing grid services.

Method and architecture for providing data-change alerts to external applications via a push service

Abstract: Method and software architecture for providing data-change alerts corresponding to data changes in a data system to external (of the data system) applications. A computer user interface is provided to enable a user to identify user interface (UI) objects corresponding to a user interface of an application used to access the data system to provide data-change alert support for. For example, the UI objects may comprise screens, views, applets, fields, and columns. Based on the alert-enabled UI objects, data-change alert triggers are generated to monitor for data-change events (e.g., inserts, updates, and deletes) that cause changes to data in the data system corresponding to those alert-enabled UI objects. In response to data changes in the data system corresponding to alert-enabled UI objects, appropriate triggers are executed to initiate generation of data-change alerts comprising data values that have been changed. The data-change alerts are then pushed to the external application.

PlanetLab: an overlay testbed for broad-coverage services

Abstract: PlanetLab is a global overlay network for developing and accessing broad-coverage network services. Our goal is to grow to 1000 geographically distributed nodes, connected by a disverse collection of links. PlanetLab allows multiple service to run concurrently and continuously, each in its own slice of PlanetLab. This paper discribes our initial implementation of PlanetLab, including the mechanisms used to impelment virtualization, and the collection of core services used to manage PlanetLab.

A Community Authorization Service for Group Collaboration

Abstract: In "Grids" and "collaboratories," we find distributed communities of resource providers and resource consumers, within which often complex and dynamic policies govern who can use which resources for which purpose. We propose a new approach to the representation, maintenance, and enforcement of such policies that provides a scalable mechanism for specifying and enforcing these policies. Our approach allows resource providers to delegate some of the authority for maintaining fine-grained access control policies to communities, while still maintaining ultimate control over their resources. We also describe a prototype implementation of this approach and an application in a data management context.

IrisNet: an architecture for a worldwide sensor Web

Abstract: We discuss about the IrisNet (Internet-scale resource-intensive sensor network services) project at Intel Research, we design an architecture and build a system that enable easy deployment of such wide-area sensing services. We aim to provide the missing software components for realizing a worldwide sensor Web. Wide-area architectures for pervasive sensing enable a new generation of powerful distributed sensing services. A worldwide sensor Web, in which users can query, as a single unit, vast quantities of data from thousands or even millions of widely distributed, heterogeneous sensors. Internet-connected PCs that source sensor feeds and cooperate to answer users' queries will form the global sensor Web's backbone. Developers of wide-area sensing services (service authors) deploy the services on this distributed infrastructure.

Mobile mesh ad-hoc networking

Abstract: An architectural solution in which standalone ad-hoc network cells are used as an extension of the backbone infrastructure in terms of network architecture or/and its service capabilities is provided. These Ad-Hoc networks will integrate to the Internet via cellular and other access networks. This integration brings new possibilities to network operators and ISP's. In its extended architecture, it is envisaged that the mobility issues are handled by utilizing the IP mobility capabilities, taking into account the mobile mesh Ad-Hoc specific requirements.

The Physiology of the Grid

Abstract: In both e-business and e-science, we often need to integrate services across distributed, heterogeneous, dynamic “virtual organizations” formed from the disparate resources within a single enterprise and/or from external resource sharing and service provider relationships. This integration can be technically challenging because of the need to achieve various qualities of service when running on top of different native platforms. We present an Open Grid Services Architecture that addresses these challenges. Building on concepts and technologies from the Grid and Web services communities, this architecture defines a uniform exposed service semantics (the Grid service); defines standard mechanisms for creating, naming, and discovering transient Grid service instances; provides location transparency and multiple protocol bindings for service instances; and supports integration with underlying native platform facilities. The Open Grid Services Architecture also defines, in terms of Web Services Description Language (WSDL) interfaces and associated conventions, mechanisms required for creating and composing sophisticated distributed systems, including lifetime management, change management, and notification. Service bindings can support reliable invocation, authentication, authorization, and delegation, if required. Our presentation complements an earlier foundational article, “The Anatomy of the Grid,” by describing how Grid mechanisms can implement a service-oriented architecture, explaining how Grid functionality can be incorporated into a Web services framework, and illustrating how our architecture can be applied within commercial computing as a basis for distributed system integration—within and across organizational domains. This is a DRAFT document and continues to be revised. The latest version can be found at http://www.globus.org/research/papers/ogsa.pdf. Please send comments to foster@mcs.anl.gov, carl@isi.edu, jnick@us.ibm.com, tuecke@mcs.anl.gov Physiology of the Grid 2

VOMS, an Authorization System for Virtual Organizations

Abstract: We briefly describe the authorization requirements, focusing on the framework of the DataGrid and DataTAG Projects and illustrate the architecture of a new service we have developed, the Virtual Organization Membership Service (VOMS), to manage authorization information in Virtual Organization scope.

OMG Data-Distribution Service: architectural overview

Abstract: The OMG Data-Distribution Service (DDS) is an emerging specification for publish-subscribe data-distribution systems. The purpose of the specification is to provide a common application-level interface that clearly defines the data-distribution service. The specification describes the service using UML, thus providing a platform-independent model that can then be mapped into a variety of concrete platforms and programming languages. The OMG DDS attempts to unify the common practice of several existing implementations [2, 5] enumerating and providing formal definitions for the QoS (Quality of Service) settings that can be used to configure the service. This paper introduces the OMG DDS specification, describes the main aspects of the model, QoS settings, and gives examples of the communication scenarios it supports.

P2Cast: peer-to-peer patching scheme for VoD service

Abstract: Providing video on demand (VoD) service over the Internet in a scalable way is a challenging problem. In this paper, we propose P2Cast - an architecture that uses a peer-to-peer approach to cooperatively stream video using patching techniques, while only relying on unicast connections among peers. We address the following two key technical issues in P2Cast: (1) constructing an application overlay appropriate for streaming; and (2) providing continuous stream playback (without glitches) in the face of disruption from an early departing client. Our simulation experiments show that P2Cast can serve many more clients than traditional client-server unicast service, and that it generally out-performs multicast-based patching if clients can cache more than of a stream's initial portion. We handle disruptions by delaying the start of playback and applying the shifted forwarding technique. A threshold on the length of time during which arriving clients are served in a single session in P2Cast serves as a knob to adjust the balance between the scalability and the clients' viewing quality in P2Cast.

Implementing a hybrid network

Abstract: A system, method and article of manufacture are provided for implementing a hybrid network. Orders for network capacity are issued based on a forecasted demand in order to develop a hybrid network. The hybrid network is analyzed o identify network problems. Then, the hybrid network is provisioned in accordance with the network problems and service requests. Usage of the hybrid network is determined and network usage control functions are initiated based on the determined usage.

Implementing enterprise resource planning (ERP) systems in small and midsize manufacturing firms

Abstract: Enterprise resource planning systems, if implemented successfully, can bestow impressive strategic, operational and information‐related benefits to adopting firms. A failed implementation can often spell financial doom. Currently, most of the information about the failures and successes are based on reports on implementations in large manufacturing and service organizations. But enterprise resource planning vendors are now steadily turning their marketing sights on small and medium‐sized manufacturers. The time is ripe for researchers to gather, analyze and disseminate information that will help these firms to implement their projects successfully. This research adopts a multiple case study approach to investigate the implementation process in small and midsize manufacturing firms in the US. The research focuses on implementation activities that foster successful installations and are developed using information gleaned from our field studies of four projects. Avenues for future research are also suggested.

Interworking architecture between 3GPP and WLAN systems

Abstract: The Third Generation Partnership Project has recently taken the initiative to develop a cellular-WLAN interworking architecture as an add-on to the 3GPP cellular system specifications. The article presents an overall view on an interworking architecture, which enables provisioning by mobile operators of a public WLAN access service for 3GPP system subscribers. The enabling functionalities include the reuse of 3GPP subscription, network selection, 3GPP system-based authentication, authorization and security key agreement using SIM/USIM card, user data routing and service access, as well as end user charging. The interworking functionalities are achieved without setting any 3GPP specific requirements for the actual WLAN access systems, but relying on the existing functionality available in a typical WLAN access network based on IEEE 802.11 standards.

Measuring Web site quality improvements: a case study of the forum on strategic management knowledge exchange

Abstract: As organizations have begun increasingly to communicate and interact with consumers via the Web, so the appropriate design of offerings has become a central issue. Attracting and retaining consumers requires acute understanding of the requirements of users and appropriate tailoring of solutions. Recently, the development of Web offerings has moved beyond the commercial domain to government, both national and international. This paper examines the results of a quality survey of a Web site provided by the OECD. The site is examined before and after a major redesign process. The instrument, WebQual, draws on previous work in Web site usability, information quality, and service interaction quality to provide a rounded framework for assessing e‐commerce and e‐government offerings. The metrics and findings demonstrate not only the strengths and weaknesses of the sites, but also the different impressions of users in member countries. These findings have implications for e‐government Web site offerings.

Design and implementation of a WLAN/cdma2000 interworking architecture

Abstract: The combination of 3G and WLAN wireless technologies offers the possibility of achieving anywhere, anytime Internet access, bringing benefits to both end users and service providers. We discuss interworking architectures for providing integrated service capability across widely deployed 3G cdma2000-based and IEEE 802.11-based networks. Specifically, we present two design choices for integration: tightly coupled and loosely coupled, and recommend the latter as a preferred option. We describe in detail the implementation of a loosely coupled integrated network which provides two kinds of roaming services, a SimpleIP service and a Mobile-IP service. We present, in detail, two new components used to build these services: a network element called a WLAN integration gateway deployed in WLAN networks; a client software on the mobile device. For a mobile device with interfaces to both technologies, our system supports seamless handoff in the presence of overlapping radio coverage.

A performance study of monitoring and information services for distributed systems

Abstract: Monitoring and information services form a key component of a distributed system, or Grid. A quantitative study of such services can aid in understanding the performance limitations, advise in the deployment of the monitoring system, and help evaluate future development work. To this end, we study the performance of three monitoring and information services for distributed systems: the Globus Toolkit/spl reg/ Monitoring and Discovery Service (MDS2), the European Data Grid Relational Grid Monitoring Architecture (R-GMA) and Hawkeye, part of the Condor project. We perform experiments to test their scalability with respect to number of users, number of resources and amount of data collected. Our study shows that each approach has different behaviors, often due to their different design goals. In the four sets of experiments we conducted to evaluate the performance of the service components under different circumstances, we found a strong advantage to caching or pre-fetching the data, as well as the need to have primary components at well-connected sites because of the high load seen by all systems.

MonALISA : A Distributed Monitoring Service Architecture

Abstract: The MonALISA (Monitoring Agents in A Large Integrated Services Architecture) system provides a distributed monitoring service. MonALISA is based on a scalable Dynamic Distributed Services Architecture which is designed to meet the needs of physics collaborations for monitoring global Grid systems, and is implemented using JINI/JAVA and WSDL/SOAP technologies. The scalability of the system derives from the use of multithreaded Station Servers to host a variety of loosely coupled self-describing dynamic services, the ability of each service to register itself and then to be discovered and used by any other services, or clients that require such information, and the ability of all services and clients subscribing to a set of events (state changes) in the system to be notified automatically . The framework integrates several existing monitoring tools and procedures to collect parameters describing computational nodes, applications and network performance. It has built-in SNMP support and network-performance monitoring algorithms that enable it to monitor end-to-end network performance as well as the performance and state of site facilities in a Grid. MonALISA is currently running around the clock on the US CMS test Grid as well as an increasing number of other sites. It is also being used to monitor the performance and optimize the interconnections among the reflectors in the VRVS system.

Using Service-Oriented Architecture and Component-Based Development to Build Web Service Applications

Abstract: Building an enterprise-scale software system is a complex undertaking. Despite decades of technological advances, the demands imposed by today’s information systems frequently stretch to breaking point a company’s ability to design, construct, and evolve its mission-critical software solutions. In particular, few new systems are designed from the ground up. Rather, a software architect’s task is commonly that of extending the life of an existing solution by describing new business logic that manipulates an existing repository of data, presenting existing data and transactions through new channels such as an Internet browser or handheld devices, integrating previously disconnected systems supporting overlapping business activities, and so on. To assist software developers, commercial software infrastructure products are now available from vendors such as Microsoft and IBM. They form the centerpiece of the approaches to software development they advocate in their .NET and WebSphere product lines, respectively. Both approaches focus on assembly of systems from distributed services [1,2]. However, is there anything new about building enterprise-scale solutions from services? How do the lessons of component-based systems apply to construction of service-based architectures (SOA)? What are the best approaches for building high quality systems for deployment to this new generation of software infrastructure products? These important questions are the topic of this paper.

MobiPADS: a reflective middleware for context-aware mobile computing

Abstract: Traditionally, middleware technologies, such as CORBA, Java RMI, and Microsoft's DCOM, have provided a set of distributed computing services that essentially abstract the underlying network services to a monolithic "black box." In a mobile operating environment, the fundamental assumption of middleware abstracting a unified distributed service for all types of applications operating over a static network infrastructure is no longer valid. In particular, mobile applications are not able to leverage the benefits of adaptive computing to optimize its computation based on current contextual situations. In this paper, we introduce the Mobile Platform for Actively Deployable Service (MobiPADS) system. MobiPADS is designed to support context-aware processing by providing an executing platform to enable active service deployment and reconfiguration of the service composition in response to environments of varying contexts. Unlike most mobile middleware, MobiPADS supports dynamic adaptation at both the middleware and application layers to provide flexible configuration of resources to optimize the operations of mobile applications. Within the MobiPADS system, services (known as mobilets) are configured as chained service objects to provide augmented services to the underlying mobile applications so as to alleviate the adverse conditions of a wireless environment.

Context-aware middleware for resource management in the wireless Internet

Abstract: The provisioning of Web services over the wireless Internet introduces novel challenging issues for service design and implementation: from user/terminal mobility during service execution, to wide heterogeneity of portable access devices and unpredictable modifications in accessible resources. In this scenario, there are frequent provision-time changes in the context, defined as the logical set of accessible resources depending on client location, access terminal capabilities, and system/service management policies. The development of context-dependent services requires novel middlewares with full context visibility. We propose a middleware for context-aware resource management, called CARMEN, capable of supporting the automatic reconfiguration of wireless Internet services in response to context changes without any intervention on the service logic. CARMEN determines the context on the basis of metadata, which include declarative management policies and profiles for user preferences, terminal capabilities, and resource characteristics. In addition, CARMEN exploits the mobile agent technology to implement mobile middleware components that follow the provision-time movement of clients to support locally their customized service access. The proposed middleware shows how metadata and mobile agents can favor component reusability and automatic service reconfiguration, by reducing the development/ deployment complexity.

Design and evaluation of a support service for mobile, wireless publish/subscribe applications

Abstract: This paper presents the design and evaluation of a support service for mobile, wireless clients of a distributed publish/subscribe system. A distributed publish/subscribe system is a networked communication infrastructure where messages are published by senders and then delivered to the receivers whose subscriptions match the messages. Communication therefore does not involve the use of explicit addresses, but rather emerges from the dynamic arrangement of publishers and subscribers. Such a communication mechanism is an ideal platform for a variety of Internet applications, including multiparty messaging, personal information management, information sharing, online news distribution, service discovery, and electronic auctions. Our goal is to support such applications on mobile, wireless host devices in such a way that the applications can, if they chose, be oblivious to the mobility and intermittent connectivity of their hosts as they move from one publish/subscribe access point to another. In this paper, we describe a generic, value-added service that can be used in conjunction with publish/subscribe systems to achieve these goals. We detail the implementation of the service and present the results of our evaluation of the service in both wireline and emulated wireless environments.

Providing contextual information to pervasive computing applications

Abstract: Pervasive computing applications are increasingly leveraging contextual information from several sources to provide users with behavior appropriate to the environment in which they reside. If these sources of contextual information are used and deployed in an ad hoc manner however they may provide overlapping functionality, fail to provide needed functionality, and require the use of inconsistent interfaces by applications. To overcome these problems, we introduce a contextual information service that provides applications with contextual information via a virtual database. Unlike previous efforts, our service provides applications a consistent, lightweight, and powerful mechanism for obtaining contextual information, and includes explicit support for the on demand computation of contextual information. We show, via example applications and a contextual information service prototype that we have implemented, how this approach can be used to allow proactive applications to adapt their behavior to match a user's current environment.

Learning for Sustainability Transition through Bounded Socio-technical Experiments in Personal Mobility

Abstract: A bounded socio-technical experiment (BSTE) attempts to introduce a new technology, service, or a social arrangement on a small scale. Many such experiments in personal mobility are ongoing worldwide. They are carried out by coalitions of diverse actors, and are driven by long term and large scale visions of advancing society’s sustainability agenda. This paper focuses on the processes of higher-order learning that occur through BSTEs. Based on the conceptual frameworks from theories of organizational learning, policy-oriented learning, and diffusion of innovation, we identify two types of learning: the first type occurs among the participants in the experiment and their immediate professional networks; the second type occurs in the society at large. Both types play a key role in the societal transition towards sustainable mobility systems. Two case studies, in which the Design for Sustainability Group at Technical University of Delft has participated, provide empirical data for the analysis. One...

Chisel: a policy-driven, context-aware, dynamic adaptation framework

Abstract: We argue that the software user, the developer, the designer and indeed the application logic itself all possess invaluable intelligence to gear how software should adapt itself to changing requirements and changing context. We present Chisel, an open framework for dynamic adaptation of services using reflection in a policy-driven, context-aware manner. The system is based on decomposing the particular aspects of a service object that do not provide its core functionality into multiple possible behaviours. As the execution environment, user context and application context change, the service object will be adapted to use different behaviours, driven by a human-readable declarative adaptation policy script. To demonstrate this framework we will provide a dynamically adaptive middleware for mobile computing. The framework will allow users and applications to make mobile-aware dynamic changes to the behaviour of various services of the middleware, and allow the addition of new unanticipated behaviours at run-time, without changing or stopping the middleware or an application that may be using it. This is achieved by implementing the behaviours as metatypes in Iguana/J, which supports non-invasive dynamic associations of metatypes to service objects without any requirement to interrupt, change or access the object's source code.

Method and system for wireless intrusion detection

Abstract: A wireless intrusion dection system (WIDS) is disclosed for monitoring both authorized and unauthorized access to a wireless portion of a network. The WIDS consists of a collect (110) and one or more nodes (120) that communicate via an out of band means that is separate from the network. Unauthorized access points (140) and unauthorized clients (160) in the network can be detected. The WIDS can be used to monitor, for example, a network implemented using the 802.11 protocol. In addition, the WIDS can be used by one company to provide a service that monitors the wireless network of another company.

Differentiated Services Quality of Service Policy Information Base

Abstract: This document describes a Policy Information Base (PIB) for a device implementing the Differentiated Services Architecture. The provisioning classes defined here provide policy control over resources implementing the Differentiated Services Architecture. These provisioning classes can be used with other none Differentiated Services provisioning classes (defined in other PIBs) to provide for a comprehensive policy controlled mapping of service requirement to device resource capability and usage.

Trust management tools for internet applications

Abstract: Trust management has received a lot of attention recently as it is an important component of decision making for electronic commerce, Internet interactions and electronic contract negotiation. However, appropriate tools are needed to effectively specify and manage trust relationships. They should facilitate the analysis of trust specification for conflicts and should enable information on risk and experience information to be used to help in decision-making. High-level trust specifications may also be refined to lower-leve implementation policies about access control, authentication and encryption. In this paper, we present the SULTAN trust management toolkit for the specification, analysis and monitoring of trust specifications. This paper will present the following components of the toolkit: the Specification Editor, the Analysis Tool, the Risk Service and the Monitoring Service.