Jesús Tomás

GBP-WAHSN: A Group-Based Protocol for Large Wireless Ad Hoc and Sensor Networks

Grouping nodes gives better performance to the whole network by diminishing the average network delay and avoiding unnecessary message forwarding and additional overhead. Many routing protocols for ad-hoc and sensor networks have been designed but none of them are based on groups. In this paper, we will start defining group-based topologies, and then we will show how some wireless ad hoc sensor networks (WAHSN) routing protocols perform when the nodes are arranged in groups. In our proposal connections between groups are established as a function of the proximity of the nodes and the neighbors available capacity (based on the nodes energy). We describe the architecture proposal, the messages that are needed for the proper operation and its mathematical description. We have also simulated how much time is needed to propagate information between groups. Finally, we will show a comparison with other architectures.

Improving networks using group-based topologies

Communication network topology design needs to address several conflicting requirements, such as minimizing the overall network diameter, minimizing the infrastructure cost, minimizing management cost, maximizing load distribution and so on. Centralized, decentralized, and partially centralized networks have their respective benefits as well as several drawbacks. It is known that grouping nodes gives better performance to the group and to the whole system, thereby avoiding unnecessary message forwarding and additional overheads. This paper proposes a survey of group-based topologies. It shows their main issues and in which real environments they could be used. The improvement of the networks by using these kinds of topologies will also be discussed. We have split group-based topologies into two classes, planar and layered group-based topologies, and we will discuss existing group-based systems in both types. Highlighting one of the main aims of the paper, their comparison, benefits and drawbacks are presented. Finally, authors will describe two group-based topologies designed by them, one for planar group-based topologies and another for layered group-based topologies, and they will be compared with different previous works. We consider this work as a starting point for researchers on new group-based topologies.

Statistical Phrase-Based Models for Interactive Computer-Assisted Translation

Obtaining high-quality machine translations is still a long way off. A post-editing phase is required to improve the output of a machine translation system. An alternative is the so called computer-assisted translation. In this framework, a human translator interacts with the system in order to obtain high-quality translations. A statistical phrase-based approach to computer-assisted translation is described in this article. A new decoder algorithm for interactive search is also presented, that combines monotone and non-monotone search. The system has been assessed in the Trans Type-2 project for the translation of several printer manuals, from (to) English to (from) Spanish, German and French.

A network management algorithm and protocol for improving QoE in mobile IPTV

Last improvements on video codecs, jointly with the use of optimized transport protocols, have brought us to provide IPTV in wireless networks. Moreover, cellular phone users are being accustomed to have all Internet services in the mobile device, through 3G or WiFi technology, with the same quality of experience (QoE) than in any desktop computer or laptop with broadband Internet connection. In this paper we present a network management algorithm and protocol for ubiquitous networks based on the QoE of the end user. First, we explain the developed protocol and algorithm, that uses the information provided by the mobile device and the bandwidth, jitter, delay and packet loss of the end user, in order to decide which is the most appropriate video features and the best coding technique to deliver the video streams. A video controller server decides which video server, from a farm of servers, is the best one for each case. We show the algorithm performance when each coding technique is changed in the server due to transcoding process, and the network performance in terms of jitter, delay and lost packets received by the end user when each coding technique is selected by the video controller server.

A quantitative method for machine translation evaluation

Accurate evaluation of machine translation (MT) is an open problem. A brief survey of the current approach to tackle this problem is presented and a new proposal is introduced. This proposal attempts to measure the percentage of words, which should be modified at the output of an automatic translator in order to obtain a correct translation. To show the feasibility of the method we have assessed the most important Spanish-Catalan translators in comparing the results obtained by the various methods.

An architecture and protocol for smart continuous eHealth monitoring using 5G

Abstract Continuous monitoring of chronic patients improves their quality of life and reduces the economic costs of the sanitary system. However, in order to ensure a good monitoring, high bandwidth and low delay are needed. The 5G technology offers higher bandwidth, lower delays and packets loss than previous technologies. This paper presents an architecture for smart eHealth monitoring of chronic patients. The architecture elements include wearable devices, to collect measures from the body, and a smartphone at the patient side in order to process the data received from the wearable devices. We also need a DataBase with an intelligent system able to send an alarm when it detects that it is happening something anomalous. The intelligent system uses machine learning in BigData taken from different hospitals and the data received from the patient to diagnose and generate alarms. Experiment tests have been done to simulate the traffic from many users to the DataBase in order to evaluate the suitability of 5G in our architecture. When there are few users (less than 200 users), we do not find big differences of round trip time between 4G and 5G, but when there are more users, like 1000 users, it increases considerably reaching 4 times more in 4G The Packet Loss is almost null in 4G until 300 users, while in 5G it is possible to keep it null until 700 users. Our results point out that in order to have high number of patients continuously monitored, it is necessary to use the 5G network because it offers low delays and guarantees the availability of bandwidth for all users.

Statistical Machine Translation Decoding Using Target Word Reordering

In the field of pattern recognition, the design of an efficient decoding algorithm is critical for statistical machine translation. The most common statistical machine translation decoding algorithms use the concept of partial hypothesis. Typically, a partial hypothesis is composed by a subset of source positions, which indicates the words that have been translated in this hypothesis, and a prefix of the target sentence. Thus, the target sentence is generated from left to right obtaining source words in an arbitrary order. We present a new approach, where the source sentence is translated from left to right and the possible word reordering is performed at the target prefix. We implemented this approach using a multi-stack decoding technique for a phrase-based model, and compared it with both a conventional approach and a monotone approach. Our experiments show how the new approach can significantly reduce the search time without increasing the search errors.

Smart System for Children's Chronic Illness Monitoring

Abstract Sick children need a continuous monitoring, but this involves high costs for the government and for the parents. The use of information and communication technologies (ICT) jointly with artificial intelligence and smart devices can reduce these costs, help the children and assist their parents. This paper presents a smart architecture for childrens chronic illness monitoring that will let the caregivers (parents, teachers and doctors) to remotely monitor the health of the children based on the sensors embedded in the smartphones and smart wearable devices. The proposed architecture includes a smart algorithm developed to intelligently detect if a parameter has exceeded a threshold, thus it may imply an emergency or not. To check the correct operation of this system, we have developed a small wearable device that is able to measure the heart rate and the body temperature. We have designed a secure mechanism to stablish a Bluetooth connection with the smartphone. In addition, the system is able to perform the data fusion in both the information packetizing process, which contributes to improve the protocol performance, and in the measured values combination, where it is used a stochastic approach. As a result, our system can fusion data from different sensors in real-time and detect automatically strange situations for sending a warning to the caregivers. Finally, the consumed bandwidth and battery autonomy of the developed device have been measured.

Phrase-based alignment models for statistical machine translation

The first pattern recognition approaches to machine translation were based on single-word models. However, these models present an important deficiency; they do not take contextual information into account for the translation decision. The phrase-based approach consists in translating a multiword source sequence into a multiword target sequence, instead of a single source word into a single target word. We present different methods to train the parameters of this kind of model. In the evaluation phase of this approach, we obtained interesting results in comparison with other statistical models.

Improving Mobile and Ad-hoc Networks performance using Group-Based Topologies

Many works related with mobile and ad-hoc networks routing protocols present new proposals with better or enhanced features, others just compare them or present an application environment, but this work tries to give another point of view. Why don’t we see the network as a whole and split it intro groups to give better performance to the network regardless of the used routing protocol?. First, we will demonstrate, through simulations, that grouping nodes in a mobile and ad-hoc networks improves the whole network by diminishing the average network delay and also the routing traffic received by the nodes. Then, we will show which one of the actual fully standardized protocols (DSR [1], AODV [2] and OLSR [3]) gives better performance to the whole network when there are groups of nodes. This paper starts a new research line and urges the researchers to think on it and design group-based protocols.