Roch H. Glitho

Mobile agents and their use for information retrieval: a brief overview and an elaborate case study

Mobile agents emerged in the mid-1990s, and have raised considerable interest in the research community. The proponents associate several benefits with their use. However, there are still very few quantitative measurements to back the claimed benefits. This article is devoted to mobile agents and their use for information retrieval. We provide a brief overview and an elaborate case study. The overview introduces the concept of mobile agent, enumerates the claimed benefits, and reviews the hindrances to widescale deployment. It also discusses the state of the art of mobile-agent-based information retrieval, including the very few quantitative studies that exist. Our case study is on information retrieval from electronic calendars for multiparty event scheduling. Many events require the participation of several parties. Prior knowledge of the date when most (if not all) targeted participants are available is often a prerequisite for scheduling them. However, identifying this date can easily turn into a nightmare, especially when the number of targeted participants is large. Nowadays, electronic agendas (e.g., MS Outlook) are stored on servers. An application can access them, retrieve information on the availability of the targeted participants, and derive the date from the information. In the case study, a mobile agent is dispatched in the network, instead of retrieving the information using the client/server paradigm. The agent visits the servers, accesses the agendas, retrieves the information, and identifies the date. Finding a date suitable for several potential participants may require the rescheduling of some events that have been previously arranged by some participants. We propose the use of agents that act as the personal agents of the participants for the negotiation inherent to this rescheduling. The measurements we have made indicate clearly that the mobile-agent-based approach outperforms its client/server counterpart even when the latter is optimized. These results can easily be transposed to most information retrieval applications, and demonstrate, for this specific application domain, the performance benefit associated with mobile agents. We now dispatch a single agent in the network. In the future, we will dispatch several agents.

RESTful web services for service provisioning in next-generation networks: a survey

Next-generation networks, as envisioned by ITU-T, are packet-based networks, capable of provisioning consistent and ubiquitous services to end users independent of the network, access technology, and devices used. RESTful web services are now being contemplated as a technology for service provisioning in NGNs. They are emerging as an alternative, which may be more adequate than SOAP-based web services in some cases. SOAP-based web services are modular applications that can be discovered and invoked over a network. RESTful web services, on the other hand, are defined as a network architectural style for distributed hypermedia systems. This article presents a survey on RESTful web services for service provisioning in NGNs. It introduces the concept of RESTful web services and reviews the state of the art of RESTful-based service provisioning in NGNs. It also provides an evaluation of the overall suitability of RESTful web services for service provisioning in NGNs, and discusses research directions. RESTful web services do show significant potential for service provisioning in NGNs. However, open issues such as publication/discovery and mechanisms for the development of complex session-based services need to be solved before its full potential can be realized.

Creating value added services in Internet telephony: an overview and a case study on a high-level service creation environment

Value added services, or more simply - services, are the critical ingredient for the success and the survival of Internet Telephony. Services can be defined as anything that goes beyond two party voice calls. Some examples are multiparty gaming, customized stock quotes and call screening. This paper focuses on service creation in Internet Telephony. Service creation plays a major role in Internet Telephony because it enables openness and programmability by offering frameworks for the development of value added services. Two principal sets of standards have emerged for Internet Telephony: H.323 from the ITU-T and SIP from the IETF. No service creation framework comes with the H.323 set. Two frameworks come with the SIP set: the Call Processing Language (CPL) and the SIP common gateway interface (CGI). Besides the IETF, other forums such as Parlay and JAIN have proposed pertinent frameworks. The first part of the paper provides an overview of the service creation frameworks for Internet Telephony. A common characteristic of these frameworks is that they require knowledge that nonexperts may not have (e.g., scripts, programming languages). High-level service creation environments may help these nonexperts. The second part of the paper presents a case study on a high level service creation environment (SCE) where pre-defined graphical components are combined into services. The environment is discussed in detail along with the service logic execution environment (SLEE) where the services are executed. The SCE and SLEE make no assumption on the service creation framework supported by the network, and any of the standard frameworks could be used provided it offers the functionality abstracted in the graphical components. We have used the Parlay APIs as a framework and the prototype is built for a SIP environment. The prototype is described and the lessons we have learned are presented.

Telecommunications management network: vision vs. reality

Since the early 1980s, the standards bodies have been specifying the telecommunications management network (TMN) principles. Millions of dollars have been spent. The TMN principles aim at being applicable across telecommunications technologies. They recommend the use of independent management networks to manage telecommunications networks, elements in the telecommunications networks (managed networks), and managing systems (in managing networks), communicating via well defined, standardized interfaces. The standards bodies envisioned TMN as a possible solution to the complex problem of telecommunications networks and services operation, administration, maintenance and provisioning (OAM and P) in the open, multivendor environment. However, the vision stumbles against the reality. Various factors still hinder the implementation of TMN-based OAM and P systems. The present article provides a tutorial on TMN by contrasting the vision and the reality. >

Wireless sensor network virtualization: early architecture and research perspectives

WSNs have become pervasive and are used in many applications and services. Usually, deployments of WSNs are task-oriented and domain-specific, thereby precluding reuse when other applications and services are contemplated. This inevitably leads to the proliferation of redundant WSN deployments. Virtualization is a technology that can aid in tackling this issue, as it enables the sharing of resources/infrastructure by multiple independent entities. In this article we critically review the state of the art and propose a novel architecture for WSN virtualization. The proposed architecture has four layers (physical layer, virtual sensor layer, virtual sensor access layer, and overlay layer) and relies on a constrained application protocol. We illustrate its potential by using it in a scenario where a single WSN is shared by multiple applications, one of which is a fire monitoring application. We present the proof-of-concept prototype we have built along with the performance measurements, and discuss future research directions.

A novel signaling system for multiparty sessions in peer-to-peer ad hoc networks

Multiparty sessions are the basis of a wealth of applications. Some examples are audio/video conferencing, distance learning and gaming. Peer-to-peer ad hoc networks are now emerging. They are useful in a wide range of application scenarios in personal, commercial, public and military environments. Very little is known today on how to handle multiparty sessions in these new networks. This paper proposes a novel signaling system for multiparty sessions in peer-to-peer ad hoc networks. The architecture relies on clustering. Requirements are derived and new principles are proposed. The principles are implemented as extensions to the session initiation protocol (SIP). Extending SIP enables easy interworking with conventional third generation telecommunication networks. The implementation is presented. We have also built a prototype, using JXTA, a middleware for peer-to-peer. The prototype is described with the measurements we have made.

A Presence-Based Architecture for the Integration of the Sensing Capabilities of Wireless Sensor Networks in the IP Multimedia Subsystem

Wireless Sensor Networks (WSN) are made up of small devices that can sense context information (e.g. space, physiology, and environment). The IP Multimedia System (IMS) aims at the convergence of Internet and cellular networks. It enables the delivery of multimedia services to end-users. Integrating the sensing capabilities of WSN in the IP multimedia subsystem will open the door to a wide range of novel multimedia services. This paper proposes a presence based architecture for the integration, focusing on how the information is conveyed from the WSN to the presence infrastructure (i.e the inbound interface). Presence is an integral part of IMS. It enables the distribution of end-user presence information (e.g. location, availability), a sub-set of context information, to interested parties, generally applications. We introduce the architecture and elaborate some of the required extensions to the 3GPP presence service. The proof of concept prototype is also described.

Signaling for multimedia conferencing in 4G: the case of integrated 3G/MANETs

Fourth-generation wireless systems are composed of coexisting and cooperating legacy and new networks. Mobile ad hoc networks are examples of new networks. They have several attractive characteristics and are gaining more and more momentum. Their integration with legacy third-generation networks is now being contemplated. Multimedia conferencing is the basis of a wealth of applications, including video conferences, multiparty games, and distance learning. Signaling is the central nerve of multimedia conferencing. It establishes, modifies, and tears down multimedia conferencing applications. This article is devoted to the signaling aspects of multimedia conferencing in 4G and focuses on the specific case of integrated 3G/MANETs. It reviews the standard 3G architecture and the emerging architectures for MANETs. This review shows that none of them is suitable for integrated 3G/MANETs. We propose a new architecture based on application-level clusters and conference gateways. We have implemented a prototype using the session initiation protocol (SIP) technology

A multi-layer architecture for wireless sensor network virtualization

Wireless sensor networks (WSNs) have become pervasive and are used for a plethora of applications and services. They are usually deployed with specific applications and services; thereby precluding their re-use when other applications and services are contemplated. This can inevitably lead to the proliferation of redundant WSN deployments. Virtualization is a technology that can aid in tackling this issue. It enables the sharing of resources/infrastructures by multiple independent entities. This position paper proposes a novel multi-layer architecture for WSN virtualization and identifies the research challenges. Related work is also discussed. We illustrate the potential of the architecture by applying it to a scenario in which WSNs are shared for fire monitoring.

A novel architecture for Web service composition

Web services enable application-to-application interactions over networks. They have functional, behavioral, non-functional, and semantic characteristics. Web service composition is the mechanism for combining and reusing existing Web services to create new Web services. In this paper, we propose a novel architecture for Web service composition. The proposed architecture extends the standard Web services business model to explicitly support Web services composition. It also enables the description of Web services with all four of their characteristics (i.e. functional, behavioral, non-functional, and semantic characteristics). Furthermore, it uses formal methods (that take into account all of these characteristics) to enable the matching, selection, and assembling of the Web services that are needed in the composition process. The architecture is made up of three components: a business model, a composition framework, and a description framework. The business model introduces three new entities: a Web service composer, a Web service composition registry, and a third-party Web service provider. The Web service composer has the overall responsibility of the composition process and is realized by the composition framework. The composition framework uses matchmaking, categorization, and assembly techniques to carry out the actual composition, taking into account all of the characteristics. The description framework provides the languages required to describe the Web services in both the business model and the composition framework. It also integrates the languages in a common semantic domain of HOL (an expressive high-level logic). These languages are SAWSDL (a semantic and functional language), MSC (a formal behavioral language), and NFSL (an XML-based non-functional language). NFSL is a simple new language that we propose, while SAWSDL and MSC are existing languages.