Efficient mobility and interoperability of software agents /

Els agents mòbils són entitats computacionals autònomes que tenen la capacitat de suspendre i prosseguir la seva execució en diferents punts de la xarxa per a dur a terme un conjunt de tasques assignades. Tot i la seva aparent simplicitat, el fet de compartir codi en diferents localitzacions, sovint heterogènies, dóna lloc a un conjunt d'inconvenients que no són senzills de solucionar. La prova és que, després de diversos anys d'esforços, el desplegament d'aquesta tecnologia no ha esdevingut una realitat. En la nostra opinió les raons principals que han obstaculitzat l'ús dels agents mòbils són la manca de seguretat, interoperabilitat i eficiència. La seguretat imposa fortes restriccions en l'ús d'aquests. No obstant actualment ja disposem d'una gran quantitat de propostes en aquesta àrea. La interoperabilitat és absolutament indispensable per a garantir que diferents tipus d'agents poden funcionar en diferents llocs i intercanviar informació. I l'eficiència és un requisit no funcional que afavoreix l'ús de la citada tecnologia. Els agents mòbils són idonis per a entorns distribuïts i heterogenis. El treball presentat en aquesta tesi està motivat per a aquest fet i comprèn quatre objectius per a millorar, en aquest ordre, la interoperabilitat, l'eficiència i la seguretat dels agents mòbils en el context dels estàndards definits per l'organització IEEE-FIPA. El primer objectiu és el disseny d'una especificació de mobilitat flexible. El segon objectiu és la proposta de mecanismes d'interoperabilitat, combinats amb l'especificació anterior, per a l'execució i mobilitat d'agents en localitzacions on no se suporten els mateixos tipus de plataformes d'agents, llenguatges de programació i arquitectures subjacents. El tercer objectiu és la proposta de mètodes per a millorar l'eficiència de la mobilitat i interoperabilitat dels agents. I, finalment, el darrer objectiu és el disseny de protocols per a tractar alguns problemes de seguretat concrets dels agents mòbils.Mobile agents are autonomous software entities that have the ability to stop and resume their execution in different network locations to accomplish a set of tasks. Despite their apparent simplicity, the fact of sharing a code in different places, in most cases heterogeneous, arises a set of issues which are far from have a simple solution. The proof is that after several years of efforts, a wide-scale deployment of mobile agents has not become a reality. In our opinion the main reasons which have hindered the adoption of mobile agents are: security, interoperability, and efficiency. Security may impose strong restrictions to the use of mobile agents. Nevertheless, enough research to satisfy the most common applications has been done in this field. Interoperability is absolutely indispensable to guarantee that different types of agents can run in different places and exchange information. And efficiency is a non functional requisite which favours the adoption of the technology. The suitability of mobile agents for distributed and heterogeneous environments is unique. The work presented in this thesis is motivated by this fact and comprises four objectives to improve, in this order, the interoperability, efficiency, and security of mobile agents in the context of the IEEE-FIPA standards. The first objective is the design of a flexible agent mobility specification. The second objective is the proposal of interoperability mechanisms to move and execute agents in several locations supporting different agent middlewares, programming languages, and underlying architectures taking advantage of the previous mobility specification. The third objective is the proposal of methods to improve the efficiency of the agent mobility and interoperability. And finally, the last objective is the design of some protocols to deal with specific security issues of mobile agents

Continual Learing of Hand Gestures for Human Robot Interaction

Human communication is multimodal. For years, natural language processing has been studied as a form of human-machine or human-robot interaction. In recent years, computer vision techniques have been applied to the recognition of static and dynamic gestures, and progress is being made in sign language recognition too. The typical way to train a machine learning algorithm to perform a classification task is to provide training examples for all the classes that need to be identified by the model. In a real-world scenario, such as in the use of assistive robots, it is useful to learn new concepts from interaction. However, unlike biological brains, artificial neural networks suffer from catastrophic forgetting, and as a result, are not good at incrementally learning new classes. In this thesis, the HAnd Gesture Incremental Learning (HAGIL) framework is proposed as a method to incrementally learn to classify static hand gestures. We show that HAGIL is able to incrementally learn up to 36 new symbols using only 5 samples for each old symbol, achieving a final average accuracy of over 90%. In addition to that, the incremental training time is reduced to a 10% of the time required when using all data available

Zenith total delay study of a mesoscale convective system : GPS observations and fine-scale modelling

Zenith Total Delay (ZTD) observations and model calculations are used to analyze a mesoscale convective system which yielded a large amount of precipitation over a short period of time in the north-western Mediterranean. ZTD observations are derived from the GPS signal delay whereas the ZTD model results are calculated by means of the MM5 mesoscale model. Large values of the root-mean-square (rms) differences between the ZTD derived from the observations and the modeling are found for the maximum activity of the mesoscale convective system. It appears that the average bias between observations and modeling results is slightly affected (20%) by the passage of the storm system which is associated to the water vapor variability of the atmosphere. We have analyzed the ZTD differences in terms of the two components: the Zenith Hydrostatic Delay (ZHD) and the Zenith Wet Delay (ZWD). The hydrostatic error is mainly caused by the differences between the elevation of the GPS stations and the model topography and is reduced when using a more accurate topography data set. We propose a correction for this error assuming hydrostatic equilibrium. The remaining average ZTD difference is associated to the ZWD and is mainly generated by inaccuracies of the mesoscale model to predict the water vapor content during the rainfall event

Continual Learning of Hand Gestures for Human-Robot Interaction

In this paper, we present an efficient method to incrementally learn to classify static hand gestures. This method allows users to teach a robot to recognize new symbols in an incremental manner. Contrary to other works which use special sensors or external devices such as color or data gloves, our proposed approach makes use of a single RGB camera to perform static hand gesture recognition from 2D images. Furthermore, our system is able to incrementally learn up to 38 new symbols using only 5 samples for each old class, achieving a final average accuracy of over 90\%. In addition to that, the incremental training time can be reduced to a 10\% of the time required when using all data available

Virtual TPM for a secure cloud: fallacy or reality?

The cloud technology has dramatically increased the virtualisation usage during the last years. Nevertheless, the virtualisation has also imposed some challenges on the security of the cloud. A remarkable case is in the usage of cryptographic hardware such as the Trusted Platform Module (TPM). A TPM is a device, physically attached to a server, that provides several cryptographic functionalities to offer a foundation of trust for the running software. Unfortunately, the virtualisation of the TPM to bring its security properties to virtual environments is not direct due to its design and security constraints. During the last years several proposals have been presented to solve the virtualisation of the TPM. Nevertheless, the virtualisation systems have not started to adopt them until very recently. This paper reviews three existing implementations of virtual TPM in the Xen and QEMU virtualisation solutions. The main contribution of the paper is an analysis of these solutions from a security perspective.This work has been co-funded by the project Trusted Cloud IPT-2011-1166-430000 of the Ministry of Economy and Competitiveness (MINECO) and the European Fund for Regional Development (FEDER)”