Luis Mengual

Clustering-based location in wireless networks

In this paper, we propose a three-phase methodology (measurement, calibration and estimation) for locating mobile stations (MS) in an indoor environment using wireless technology. Our solution is a fingerprint-based positioning system that overcomes the problem of the relative effect of doors and walls on signal strength and is independent of network device manufacturers. In the measurement phase, our system collects received signal strength indicator (RSSI) measurements from multiple access points. In the calibration phase, our system utilizes these measurements in a normalization process to create a radio map, a database of RSS patterns. Unlike traditional radio map-based methods, our methodology normalizes RSS measurements collected at different locations (on a floor) and uses artificial neural network models (ANNs) to group them into clusters. In the third phase, we use data mining techniques (clustering) to optimize location results. Experimental results demonstrate the accuracy of the proposed method. From these results it is clear that the system is highly likely to be able to locate a MS in a room or nearby room.

A Fuzzy Multi-agent System for Secure Remote Control of a Mobile Guard Robot

This paper presents a secure multi-agent architecture running on a Web environment. It is directed at monitoring mobile robots used for surveillance in sensitive environments (nuclear plants, military grounds) and domotic applications in smart buildings. Our Guard Robots are semi-autonomous mobile robots providing video streams encrypted via wireless to existing watchguard systems on Internet. In our Web system the robot movement must be controlled in real time using a joystick while the robot’s position is obtained using a Webcam carried by the robot. The problem arises because the used network is not time deterministic and the bandwidth is limited and evolves dynamically. Although the best image quality is desired, a low-resolution image can be enough to navigate and avoid obstacles. We suggest a solution focused on a multi-agent architecture in which agents have fuzzy controllers and provide the best image quality for the available bandwidth, CPU power, video size and cipher engine.

Automatic implementation system of security protocols based on formal description techniques

We present an automatic implementation system of security protocols based in formal description techniques. A sufficiently complete and concise formal specification that has allowed us to define the state machine that corresponds to a security protocol has been designed to achieve our goals. This formal specification makes it possible to incorporate in a flexible way the security mechanisms and functions (random numbers generation, timestamps, symmetric-key encryption, public-key cryptography, etc). Our solution implies the incorporation of an additional security layer LEI (Logical Element of Implementation) in the TCP/IP architecture. This additional layer be able both to interpret and to implement any security protocol from its formal specification. Our system provides an applications programming interface (API) for the development of distributed applications in the Internet like the e-commerce, bank transfers, network management or distribution information services that makes transparent to them the problem of security in the communications.

Multi-agent location system in wireless networks

Highlights? A Multi-Agent Architecture and a methodology for indoor location is proposed. ? Mobile Station will have Fuzzy Location Agent (FLA) with minimum capacity processing. ? FLA establish its location on a plan of the floor of the building. ? FLA communicates with Fuzzy Location Manager Software Agent (FLMSA). ? FLMSA use fuzzy logic to estimation location based on a normalization process of RSS. In this paper we propose a flexible Multi-Agent Architecture together with a methodology for indoor location which allows us to locate any mobile station (MS) such as a Laptop, Smartphone, Tablet or a robotic system in an indoor environment using wireless technology. Our technology is complementary to the GPS location finder as it allows us to locate a mobile system in a specific room on a specific floor using the Wi-Fi networks.The idea is that any MS will have an agent known at a Fuzzy Location Software Agent (FLSA) with a minimum capacity processing at its disposal which collects the power received at different Access Points distributed around the floor and establish its location on a plan of the floor of the building. In order to do so it will have to communicate with the Fuzzy Location Manager Software Agent (FLMSA). The FLMSAs are local agents that form part of the management infrastructure of the Wi-Fi network of the Organization.The FLMSA implements a location estimation methodology divided into three phases (measurement, calibration and estimation) for locating mobile stations (MS). Our solution is a fingerprint-based positioning system that overcomes the problem of the relative effect of doors and walls on signal strength and is independent of the network device manufacturer.In the measurement phase, our system collects received signal strength indicator (RSSI) measurements from multiple access points. In the calibration phase, our system uses these measurements in a normalization process to create a radio map, a database of RSS patterns. Unlike traditional radio map-based methods, our methodology normalizes RSS measurements collected at different locations on a floor. In the third phase, we use Fuzzy Controllers to locate an MS on the plan of the floor of a building.Experimental results demonstrate the accuracy of the proposed method. From these results it is clear that the system is highly likely to be able to locate an MS in a room or adjacent room.

Towards an architecture for semiautonomous robot telecontrol systems

The design and development of a computational system to support robot-operator collaboration is a challenging task, not only because of the overall system complexity, but furthermore because of the involvement of different technical and scientific disciplines, namely, Software Engineering, Psychology and Artificial Intelligence, among others. In our opinion the approach generally used to face this type of project is based on system architectures inherited from the development of autonomous robots and therefore fails to incorporate explicitly the role of the operator, i.e. these architectures lack a view that help the operator to see him/herself as an integral part of the system. The goal of this paper is to provide a human-centered paradigm that makes it possible to create this kind of view of the system architecture. This architectural description includes the definition of the role of operator and autonomous behaviour of the robot, it identifies the shared knowledge, and it helps the operator to see the robot as an intentional being as himself/herself.

Dynamic Quality Control Based on Fuzzy Agents for Multipoint Videoconferencing

Real-time multimedia streaming applications are becoming increasingly popular on the Internet; however, the users of these streaming services often find their quality to be insufficient. When the services are based on multipoint videoconferencing, it is difficult to reach a constant, suitable level of quality on the video transmissions. In this paper, we propose to increase the overall quality of multipoint videoconferencing by dynamically acting on the JPEG quality parameter of each individual video conference. To do this, we assign a fuzzy agent controller to each single video conference. Since the agent’s fuzzy logic is based on frame ratios (and JPEG qualities), the videoconference qualities will be dynamically equilibrated when a bottleneck is reached in any of the hardware resources supporting the system. This work includes a complete set of tests where the results of the fuzzy agents are compared with the optimum values reached by each multipoint videoconference: the proposed fuzzy architecture provides very good dynamic control of the video conference qualities; moreover, its use will be particularly interesting in mobile environments, where the devices are heterogeneous and present limited processing capabilities.

Cooperative Visualization Framework Based on Video Streaming and Real-Time Vectorial Information

The essential purpose of this paper is to describe a framework, in a simple and complete way, which enables the concurrent visualization of audio/video streaming combined with its corresponding synchronous cooperative vectorial information. The architecture presented uses Java JMF API, which offers a simple, robust, extendable, multi-platform solution. It also requires no direct maintenance as regards the incorporation of future video cameras and codecs that come out on the market. Instead of the typical separate presentation of videoconferencing and its corresponding preset additional information, we offer the possibility of combining the video image with real-time vectorial information. All the combined bitmap and vectorial information is shared and can be interactively modified by the clients which are using the cooperative visualization framework. The current prototype RTCIM (Real Time Cooperative Information Manager) offers a complete API to implement cooperative applications based on multiple audio/video sessions.