Catálogo de publicaciones - libros

We propose a distributed system that enables global and ubiquitous health monitoring of patients. The biomedical data will be collected by wearable health diagnostic devices, which will include various types of sensors and will be transmitted towards the corresponding Health Monitoring Centers. The permanent medical data of patients will be kept in the corresponding Home Data Bases, while the measured biomedical data will be sent to the Visitor Health Monitor Center and Visitor Data Base that serves the area of present location of the patient. By combining the measured biomedical data and the permanent medical data, Health Medical Centers will be able to coordinate the needed actions and help the local medical teams to make quickly the best decisions that could be crucial for the patient health, and that can reduce the cost of health service.

The pervasive Internet and the massive deployment of sensor devices have lead to a huge heterogeneous distributed system connecting millions of data sources and customers together [Fra01]. On the one hand, mediation systems [BGL+99,DNJT05] using XML as an exchange language have been proposed to federate data accross distributed heterogeneous data sources. On the other hand, work [MSFC02, AML05, BGS01, NDK+03] have been done to integrate data from sensors. The challenge is now to integrate data coming from both ”classical” data (DBMS, Web sites, XML files) and ”dynamic” data (sensors) in the context of an ad-hoc network, and finally, to adapt queries and result to match the client profile.

We propose to use the TGV model [TDNL06, TDNL07a] as a mobile agent to query sources across devices (sources and terminal) in the context of a rescue coordination system. This work is integrated in the PADAWAN project.

Mobile devices are pursuing the succession of desktop PCs these days. Cyber Foraging is the project that investigated overcoming scarce computing resources and reducing the power consumptions of mobile devices. In this paper, we propose a framework for remote execution of mobile devices in the way of delivering user data and invoking and manipulating the software of a surrogate with VNC-style interface. This resource furnishing system has the merits of remote application execution, and automatic file transfer. Remote execution is provided via VNC-style interface that is user-friendly. Performance evaluation shows the feasibility of the resource furnishing system, for both data transfers over wired and wireless network.

In ubiquitous computing environment, people carrying their mobile devices (eg., mobile phone, PDA, embedded devices) expect to access locally hosted services or resources anytime, anywhere. These mobile devices have restricted capabilities and security supports. Traditional security management systems used definite access control policies for each role or user in each domain server or agent. But in ubiquitous environment, it is hard to specify authorization policies for mobile users and it is inflexible and unavailable for security management of users or mobile devices. To solve these problems, we need trust-based management mechanism as a reference to security management systems. Trust model contains trust relationship and calculation of trust value. Experiences and recommendations are the factors to calculate trust value. In this paper, we design a trust model to calculate trust value and a trust management architecture which can be running in various domain servers and mobile devices.

In most DiffServ networks there is a bandwidth broker (BB) that manages the network resources. One of the many tasks of this broker is to perform admission control on the flows entering the network. When there are many frequent calls, the network is large, or the admission control scheme is very complex, the bandwidth broker can become part of the problem instead of the solution. In those cases the broker might act as a bottleneck, limiting the number of flows entering the network and rejecting some of them even if there are still enough resources available. This is why distributed and hierarchical architectures of bandwidth brokers are needed. We introduce PoQBA: an algorithm that adapts book-ahead optimization to path oriented hierarchical broker architecture. The results show that the performance of this algorithm has several advantages compared to normal hierarchical systems and the Hose model.

The rapidly growing mobile demands have reinforced the network providers to emphasize on the basic customer needs and the resource management. The two main areas such as capacity management and data service provisions have engulfed the research field. This research paper attempts to cover both these issues in terms of Call Admission Control (CAC). Paper presents an adaptive technique built upon our previous static CAC research. The scheme provides differentiated admission to various delay sensitive (DS) and delay tolerant (DT) traffic streams for both Handover Request (HOR) and New call Request (NCR) according to current load intensity. It is based on an effective pre-emption priority in order to reduce the forced handover failure probability. Service nature and customer behaviour have been considered to lay down the different levels of priorities that were assigned at different stages of CAC Scheme in order to achieve optimal quality of service (QoS) for urban area (metropolitan) cell.

A wireless sensor network consists of many micro-sensor nodes distributed throughout an area of interest. Each node has a limited energy supply and generates information that needs to be communicated to a sink node. The basic operation in such a network is the systematic gathering and transmission of sensed data to a base station for further processing. During data gathering, sensors have the ability to perform in-network aggregation (fusion) of data packet routes to the base station. The lifetime of such a sensor system can be defined as the time during which the sensor information is gathered from all of the sensors and combined at the base station. Given the location of the sensors, the base station and the available energy at each sensor, the main interest is to find an efficient manner in which data can be collected from the sensors and transmitted to the base station at a given rate, so as to maximize the system lifetime. A zone based data aggregation scheduling scheme is presented to accomplish this. The experimental results demonstrate that the proposed protocol significantly outperforms other methods in terms of the energy saving and system lifetime.

Due to the rising popularity of multimedia applications and potential commercial usages of mobile ad hoc networks (MANETs), quality of service (QoS) in MANET has become necessary to support those needs. In this paper, we propose a QoS aware multicast routing protocol (QMRP) based on mesh architecture which offers bandwidth guarantees for applications in MANETs. Experimental evaluations are carried out in a simulated environment. The results show that the proposed protocol outperforms ODMRP, a mesh-based multicast routing protocol in a variety of environments.

There are many PCs in a PC room. For example, there are 500 PCs in our University. Each PC has a HDD, which is typically not full. If the disk utilization is 50% and each PC has a 240GB HDD, there is 60TB (500x120GB) free disk space. The total size of the unused capacity of these HDDs is nearly equal to the capacity of a file server. Institutions, however, tend to buy expensive appliance file servers. In this paper, we propose an efficient large-scale storage system that combines client free disk space. We have developed a java-based toolkit to construct a virtual large-scale storage system, which we call VLSD (Virtual Large-scale Disk). This toolkit is implemented in Java and consists of RAID (Redundant Arrays of Inexpensive/Independent Disks) and NBDs (Network Block Device). Using VLSD, we show how to construct a large disk that consists of multiple free spaces distributed over networks. VLSD supports typical RAID and other utility classes. These can be combined freely with one another.

Default logic is often used for solving knowledge representation problems in a compact, robust and flexible way. One of goals of intelligent systems is to provide efficient evaluation students’ responces. Often they operate only with the answers to a single question addressing learning a new term, understanding a new concept or mastering a new skill. However, experimental practice shows that asking several questions about the same item results in inconsistent and/or incomplete feedback, i.e. some of the answers are correct while others are partially correct or even incorrect. In this paper we propose use of default logic in an intelligent tutoring system as a way of resolving the problem with inconsistent and/or incomplete input.