M. Adel Serhani

Performance Evaluation of Mobile Web Services

Due to the advances on mobile technology, it is becoming feasible to host Web Services on a mobile device, making it perceived as potential data collector and provider. Hosting Web Services on mobile devices gains in importance when it comes to deliver real-time contextual data, such as current location or real-time heart rate. In addition to the characteristics of the available network, the usability of the Mobile Host depends on computational resources of the device itself. Currently, some emerging lightweight frameworks to host web services on mobile devices have been developed. They are recognized for their low resources footprint but they are barely tested. Consequently, the potential of utilizing them in real life settings is not known yet. In this paper, we address this issue and we propose to test the performance of Web Services hosted on mobile devices. We first propose an architecture that allows the deployment of Web Services on mobile devices. The architecture implements an important feature that provides the possibility of resuming and managing the connection state when disconnections happen. Then, we identify and evaluate the QoS of these web services such as response time, availability, throughput, and scalability. We also evaluate the overall performance of the mobile device host with main focus on the battery consumption. We applied our experiments to both SOAP and RESTful Web Services. The results we have obtained are promising and confirm the fact that RESTful Web Services are more convenient for mobile devices as their QoS does not degrade considerably and is kept at a satisfactory level. It also proves the potential hosting of Web Services on current mobile devices with acceptable battery consumption.

A New Approach for Quality Enforcement in Communities of Web Services

Nowadays, Web Services are considered as de facto and attracting distributed approach of application/services integration over the Internet. Web Services can also operate within communities to improve their visibility and market share. In a community, Web Services usually offer competing and/or complementing services. In this paper, we augment the community approach by defining a specific-purpose community to monitor Web Services operating in any Web Services community. This monitoring community consists of a set of Web Services capable of observing other Web Services. Clients, providers, as well as managers of communities can make use of the monitoring community to check if a Web Service is operating as expected. This paper defines the overall architecture of the monitoring community, the business model behind, different rules and terms to be respected by its members, services it offers to its various classes of customers. The paper also presents promising experimental results using the monitoring community.

A WSN-driven service discovery technique for disaster recovery using mobile ad hoc networks

Mobile ad hoc networks (MANET) can be used quite effectively to manage resource allocation in operations such as search and rescue, military combat, and firefighting. In the event that an operations area, e.g. in case of disaster rescue operations, is large, the use of Wireless Sensor Networks (WSNs) can be crucial in locating the spots of highest need of rescue resources. We can adapt the techniques of service discovery in MANET for use in the process of searching for and allocating the most proper rescue resource for encountered emergency situations and needs. This service discovery operation can therefore be triggered by findings of the WSNs that have been deployed in several locations within the operations area. We call the emergency response personnel “service providers”. Service providers are equipped with lightweight communication devices. In this study, we devise the protocol by which this entire operation is conducted. We also experiment with the proposed technique and present some results that show its performance under different operating conditions.

Towards a best-effort framework for developing smart mobile applications

Despite the rapid growth of the mobile technology, mobile devices are still considered as resource constrained with limited battery. Same computations are awkward to be undertaken on these devices with limited processing capabilities. Other processes are costly in terms of battery consumption. Ideally, mobile applications will have the possibility to decide either to do a computation locally or remotely depending on the current device capabilities status. Making such decision is very challenging as many interrelated factors are to be considered (e.g. network connection, battery level, and processing capabilities). In this paper, we propose a framework that supports developers in implementing such smartness fitness within their mobile applications. This solution provides approaches in form of algorithms to instrument code of mobile applications to behave in smart way. Incorporating these algorithms will allow for on-the-fly decision of local versus remote computation using a calculated cost function. We conducted some experimental scenarios to evaluate the usability and effectiveness of our decision-based algorithms. The results we have obtained prove that for the same computation, depending on the size of data, the network status and the device status, the decision of the engine may differ.

A Policy-based Framework for QoS Management in Service Oriented Environments

The successful integration of the Service Oriented Architecture (SOA) in large distributed environments greatly depends on their support of quality of service (QoS) management. The aim of QoS management is to guarantee diverse QoS levels to users issuing requests from a variety of platforms and underlying networks. In this paper, we present our policy-based framework for QoS management in SOA environment with both traditional and mobile users. The framework is based on a QoS broker that is in charge of mediating between service requesters and service providers, and carrying out various QoS management operations. It is also in charge of handling appropriately mobile users that are using various handheld devices to request services.

Mobility-Aware Selection of Mobile Web Services

Quality of Web Service (QoWS) support for Mobility-aware Web services (MWS) is critical for mobile users since it relies on the available resources on mobile devices consuming these services. In this paper, we propose a selection model for MWS based on QoWS and device resources requirements. The main purpose of the model is to support the client in selecting MWS based on desired QoWS as well as on its device resources availability. We propose a verification scheme to verify the conformity of claimed MWS QoWS and required device resources compared to the published one. The verification is used to support selection of MWS. The implementation of our model is discussed and the importance of our verification scheme is highlighted.

On the Performance of Hosting Web Services on Mobile Devices

Mobile devices and applications have traditionally been seen as data consumers. However, as their computation capabilities are increasing, they are becoming perceived as potential data collectors and providers, and even as hosts for web services. In fact, mobile web services gain in importance when it comes to deliver real-time contextual data, such as current location or real-time heart rate. Some emerging lightweight frameworks to host web services on mobile devices have been developed. They are recognized for their low resource footprint. However, they are barely tested and the potential of utilizing them in real-life settings is not known yet. In this paper, we present an architecture to test web services hosted on mobile devices as well as some preliminary results. We target to evaluate the QoS of these web services such as their response time, availability, throughput, and scalability and to evaluate the overall performance of mobile device host with main focus on the battery consumption.

MSOA: Mobility-Aware Service Oriented Architecture

Mobility-aware Web services (MWS) should become nowadays an important research area as the number of powerful mobile devices proliferates and their usage for daily business transaction increases. Quality of Web Service (QoWS) assurance for MWS is very crucial for mobile users, however, it is highly affected by the available resources on mobile devices consuming these services and the performance of MWS. In this paper, we propose an architecture for MWS selection based on QoWS and resources requirements. The main purpose of the architecture is to support the client in selecting MWS based on desired QoWS as well as on its device resources availability. This architecture requires a concise description of QoWS and resources requirements. For this purpose, the architecture proposes a verification scheme to verify the conformity of claimed MWS QoWS and required device resources compared to the published one. A set of validation test cases are executed to measure, for each specific MWS operation: the required battery consumption, memory, CPU, and network throughput. The verification is used as input to a three-tier selection process in which selected MWS are those who passed the verification test cases. As proof of concept, a prototype has been implemented to evaluate the verification scheme and show its importance in selecting the best MWS while supporting the QoWS and the required device resource availability.