QoS multicast routing protocol oriented to cognitive network using competitive coevolutionary algorithm

The human intervention in the network management and maintenance should be reduced to alleviate the ever-increasing spatial and temporal complexity. By mimicking the cognitive behaviors of human being, the cognitive network improves the scalability, self-adaptation, self-organization, and self-protection in the network. To implement the cognitive network, the cognitive behaviors for the network nodes need to be carefully designed. Quality of service (QoS) multicast is an important network problem. Therefore, it is appealing to develop an effective QoS multicast routing protocol oriented to cognitive network. In this paper, we design the cognitive behaviors summarized in the cognitive science for the network nodes. Based on the cognitive behaviors, we propose a QoS multicast routing protocol oriented to cognitive network, named as CogMRT. It is a distributed protocol where each node only maintains local information. The routing search is in a hop by hop way. Inspired by the small-world phenomenon, the cognitive behaviors help to accumulate the experiential route information. Since the QoS multicast routing is a typical combinatorial optimization problem and it is proved to be NP-Complete, we have applied the competitive coevolutionary algorithm (CCA) for the multicast tree construction. The CCA adopts novel encoding method and genetic operations which leverage the characteristics of the problem. We implement and evaluate CogMRT and other two promising alternative protocols in NS2 platform. The results show that CogMRT has remarkable advantages over the counterpart traditional protocols by exploiting the cognitive favors

Resource allocation technique for powerline network using a modified shuffled frog-leaping algorithm

Resource allocation (RA) techniques should be made efficient and optimized in order to enhance the QoS (power & bit, capacity, scalability) of high-speed networking data applications. This research attempts to further increase the efficiency towards near-optimal performance. RA’s problem involves assignment of subcarriers, power and bit amounts for each user efficiently. Several studies conducted by the Federal Communication Commission have proven that conventional RA approaches are becoming insufficient for rapid demand in networking resulted in spectrum underutilization, low capacity and convergence, also low performance of bit error rate, delay of channel feedback, weak scalability as well as computational complexity make real-time solutions intractable. Mainly due to sophisticated, restrictive constraints, multi-objectives, unfairness, channel noise, also unrealistic when assume perfect channel state is available. The main goal of this work is to develop a conceptual framework and mathematical model for resource allocation using Shuffled Frog-Leap Algorithm (SFLA). Thus, a modified SFLA is introduced and integrated in Orthogonal Frequency Division Multiplexing (OFDM) system. Then SFLA generated random population of solutions (power, bit), the fitness of each solution is calculated and improved for each subcarrier and user. The solution is numerically validated and verified by simulation-based powerline channel. The system performance was compared to similar research works in terms of the system’s capacity, scalability, allocated rate/power, and convergence. The resources allocated are constantly optimized and the capacity obtained is constantly higher as compared to Root-finding, Linear, and Hybrid evolutionary algorithms. The proposed algorithm managed to offer fastest convergence given that the number of iterations required to get to the 0.001% error of the global optimum is 75 compared to 92 in the conventional techniques. Finally, joint allocation models for selection of optima resource values are introduced; adaptive power and bit allocators in OFDM system-based Powerline and using modified SFLA-based TLBO and PSO are propose

Differential Evolution: A Survey and Analysis

Differential evolution (DE) has been extensively used in optimization studies since its development in 1995 because of its reputation as an effective global optimizer. DE is a population-based metaheuristic technique that develops numerical vectors to solve optimization problems. DE strategies have a significant impact on DE performance and play a vital role in achieving stochastic global optimization. However, DE is highly dependent on the control parameters involved. In practice, the fine-tuning of these parameters is not always easy. Here, we discuss the improvements and developments that have been made to DE algorithms. In particular, we present a state-of-the-art survey of the literature on DE and its recent advances, such as the development of adaptive, self-adaptive and hybrid techniques.http://dx.doi.org/10.3390/app810194

Large-Scale Evolutionary Optimization Using Multi-Layer Strategy Differential Evolution

Differential evolution (DE) has been extensively used in optimization studies since its development in 1995 because of its reputation as an effective global optimizer. DE is a population-based meta-heuristic technique that develops numerical vectors to solve optimization problems. DE strategies have a significant impact on DE performance and play a vital role in achieving stochastic global optimization. However, DE is highly dependent on the control parameters involved. In practice, the fine-tuning of these parameters is not always easy. Here, we discuss the improvements and developments that have been made to DE algorithms. The Multi-Layer Strategies Differential Evolution (MLSDE) algorithm, which finds optimal solutions for large scale problems. To solve large scale problems were grouped different strategies together and applied them to date set. Furthermore, these strategies were applied to selected vectors to strengthen the exploration ability of the algorithm. Extensive computational analysis was also carried out to evaluate the performance of the proposed algorithm on a set of well-known CEC 2015 benchmark functions. This benchmark was utilized for the assessment and performance evaluation of the proposed algorithm

ESTUDIO DEL EFECTO DE FACTORES EXTERNOS SOBRE LAS REDES WLAN Y DISEÑO DE UN ALGORITMO COGNITIVO ENERGÉTICAMENTE EFICIENTE

[EN] Nowadays there are many works which analyze and seek to improve the performance of Wireless Local Area Networks (WLANs) from different perspectives. A great deal of them is focused on design aspects, such as frequency distribution or channel assignment. Therefore, as these features have already been widely studied, my efforts have been directed to study other conditions that also could affect their performance and that have not been analyzed in depth yet. The main goal of this Ph.D. dissertation has been to perform a detailed study that researches the weather's impact on the performance of WLANs IEEE 802.11b/g. Two different WLAN scenarios have been analyzed to validate the results and to find precise relations. From conclusions of these previous analysis, the second objective has been to design a cognitive protocol that based on weather conditions and network performance parameters, allows networks to adjust their transmission features in order to overcome such impact. In order to conduct this study, firstly it was necessary to study which statistical methods could be used to extract the level of correlation between performance parameters of networks and weather conditions running at the same time. Secondly, I had to know which performance parameters the outdoor WLAN of Universitat Politècnica de València (UPV) could provide, and select them according to my objective. Then, I defined the period of time in which these parameters were gathered periodically. The next step was to select and collect the weather conditions from a close weather station during the same period of time. Finally, I had to perform a detailed pre-processing to put all of the volume of data in order and data were statistically analyzed. Results were successful; however there were several problems due to the variability derived from a real WLAN scenario. Therefore, an experimental setup was required in order to check the obtained results. It entailed to design and to develop an outdoor point-to-multipoint IEEE 802.11b/g link and to analyze again the weather's impact. Multiple points were considered in order to take into account different distances in the performed evaluation and to examine the behavior of different modulation schemes working under the same weather conditions. From these results, a cognitive algorithm was designed in order to reduce the weather's impact on IEEE 802.11b/g networks. One key aspect was to ensure it was energy efficient. This protocol was simulated and the obtained results were satisfactory in terms of both energy efficiency and network performance. To conclude, other external factor to WLANs studied in this Ph.D thesis has been the specific absorption rate. It deals with a current public health worry because it is used to measure the body tissue exposure to electromagnetic fields. Obviously, signal absorption by human bodies affects to the performance of WLANs and so, this parameter should be also taken into account when deploying efficient networks. For this reason, this study has been also included in this thesis.[ES] Hoy en día existen muchos trabajos que analizan e intentan mejorar el rendimiento de las redes de área local inalámbricas desde diferentes perspectivas. Gran parte de estos trabajos se centran en aspectos de diseño, como son la distribución de frecuencias o la asignación de canales. Por lo tanto, como estos aspectos ya han sido ampliamente estudiados, los esfuerzos de esta tesis se han dirigido a estudiar otros factores que también podrían afectar a su rendimiento y que no han sido analizadas en profundidad todavía. El objetivo principal de esta tesis doctoral ha sido realizar un estudio detallado que analice el impacto de las condiciones meteorológicas sobre el rendimiento de las redes IEEE 802.11b/g. Para realizar este estudio, se han analizado dos escenarios reales con el fin de verificar los resultados y encontrar relaciones precisas. A partir de las conclusiones de estos análisis previos, el segundo objetivo ha sido diseñar un algoritmo cognitivo que, en base a las condiciones meteorológicas y a los parámetros de rendimiento de red, permita a las redes ajustar sus características de transmisión con el fin de superar tal impacto. Con el fin de llevar a cabo este estudio, primero fue necesario estudiar qué métodos estadísticos podían ser utilizados para extraer el nivel de correlación entre los parámetros de rendimiento de las redes y las condiciones meteorológicas del entorno. En segundo lugar, se tuvo que analizar qué parámetros de rendimiento de red se podían extraer de la red exterior de la UPV y seleccionarlos de acuerdo con el objetivo perseguido. A continuación, se definió el periodo de tiempo durante el cual se almacenarían los parámetros seleccionados de forma periódica. El siguiente paso fue seleccionar y almacenar las condiciones meteorológicas de una estación cercana durante el mismo periodo de tiempo. Finalmente, se realizó un preprocesado detallado con el fin de poner en orden todo el volumen de datos y se analizaron estadísticamente. Los resultados fueron exitosos, sin embargo aparecieron varios problemas por el hecho de estudiar una red real muy variable. Por lo tanto, se tuvo que desarrollar un escenario experimental con el fin de verificar los resultados. Para ello se diseñó y desarrolló un enlace exterior IEEE 802.11b/g punto a multipunto, y se analizó de nuevo el impacto de las condiciones meteorológicas. Se consideró un enlace multipunto para analizar también cómo influía el impacto del tiempo según la distancia y los diferentes esquemas de modulación. A partir de los resultados, se diseñó un algoritmo cognitivo energéticamente eficiente con el fin de reducir el impacto de los fenómenos meteorológicos en las redes IEEE 802.11b/g. Dicho algoritmo ha sido simulado y los resultados obtenidos han sido satisfactorios, tanto en términos de eficiencia energética como de rendimiento de la red. Para concluir, otro factor externo que se ha estudiado en esta tesis ha sido la tasa de absorción específica. Este parámetro está relacionado con una de las grandes preocupaciones actuales en cuanto a salud pública, ya que se utiliza para medir la exposición de los tejidos del cuerpo humano a los campos electromagnéticos. Obviamente, la absorción de señal por parte del cuerpo humano afecta a las redes y, por lo tanto, este parámetro se debería tener en cuenta a la hora de diseñar redes eficientes. Por esta razón se ha incluido en esta tesis doctoral.[CA] Actualment hi ha molts treballs que analitzen i intenten millorar el rendiment de les xarxes d'àrea local sense fils des de diferents perspectives. Gran part d'aquests treballs es focalitzen en aspectes de disseny, com són la distribució de freqüències o l'assignació de canals. Per tant, com aquests aspectes ja han sigut àmpliament estudiats, els esforços d'aquesta tesi doctoral s'han dirigit a estudiar altres factors que també podrien afectar al seu rendiment i que encara no han sigut analitzats amb profunditat. L'objectiu principal d'aquesta tesi doctoral ha sigut realitzar un estudi minuciós per analitzar l'impacte de les condicions meteorològiques sobre el rendiment de les xarxes IEEE 802.11b/g. Per a realitzar aquest estudi s'han analitzat dos escenaris reals per tal de verificar els resultats i trobar relacions precises. A partir de les conclusions d'aquests anàlisis previ, el següent objectiu ha sigut dissenyar un algoritme cognitiu que, en base a les condicions meteorològiques i als paràmetres de rendiment de la xarxa, permeti a les xarxes ajustar les seues característiques de transmissió per tal de superar tal impacte. Per tal de dur a terme aquest estudi, primer va ser necessari estudiar quins mètodes estadístics podien ser utilitzats per extraure el nivell de correlació entre els paràmetres de rendiment de les xarxes i les condicions meteorològiques de l'entorn. En segon lloc, es va haver d'analitzar quins paràmetres de rendiment es podien extraure de la xarxa exterior de la UPV i es van seleccionar d'acord a l'objectiu plantejat. A continuació, es va definir el període temporal al llarg del qual s'emmagatzemarien els paràmetres seleccionats de manera periòdica. El següent pas va ser seleccionar i emmagatzemar les condicions meteorològiques d'una estació propera durant el mateix període de temps. Finalment, es va realitzar un preprocessat per tal de posar en ordre tot el volum de dades i es van analitzar estadísticament. Els resultats van ser exitosos, però van aparèixer diversos problemes pel fet d'estudiar una xarxa real molt variable. Per tant, es va haver de desenvolupar un escenari experimental amb l'objectiu de verificar els resultats. Per aquesta raó es va dissenyar i implementar un enllaç exterior IEEE 802.11b/g punt a multipunt, i es va analitzar de nou l'impacte de les condicions meteorològiques. Es va considerar un enllaç multipunt per tal de d'analitzar també com influïa el impacte del temps segons la distància i els diferents esquemes de modulació. A partir d'aquests resultats, es va dissenyar un algoritme cognitiu energèticament eficient per tal de reduir l'impacte dels fenòmens meteorològics sobre les xarxes IEEE 802.11b/g. Aquest algoritme va ser simulat i els resultats obtinguts van ser satisfactoris, tant en termes d'eficiència energètica com de rendiment de la xarxa. va comprovar que la proposta aporta millores. Per concloure, un altre factor extern que s'ha estudiat en aquesta tesi doctoral ha sigut la taxa d'absorció específica. Aquest paràmetre està relacionat amb una de les preocupacions actuals pel que fa a la salut pública, ja que s'utilitza per a mesurar l'exposició dels teixits del cos humà als camps electromagnètics. Òbviament, aquesta absorció de la senyal afecta el rendiment de les xarxes i, per això, aquest paràmetre s'hauria de tenir en compte a l'hora d'implementar futures xarxes sense fils eficients. Per aquesta raó s'ha inclòs en aquesta tesi doctoral.Bri Molinero, D. (2015). ESTUDIO DEL EFECTO DE FACTORES EXTERNOS SOBRE LAS REDES WLAN Y DISEÑO DE UN ALGORITMO COGNITIVO ENERGÉTICAMENTE EFICIENTE [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/53450TESI

Unfolding the convergence paradox: The case of mobile voice-over-IP in the UK.

The notion of digital and in particular Information and Communication Technology (ICT) convergence has, over the past 40 years, been in the centre of many technological discourses in different functional systems of society: from the economic and mass media to the legal and political systems. Recently, a new convergence discourse has emerged around next-generation wireless infrastructures and services. One manifestation can be seen in discussion of the mobile Internet, and in particular of new converging services connecting mobile telephony networks to the Internet. Contrary to the prominence of the topic in other domains, the Information Systems community has relegated the notion of ICT convergence to the sidelines. Only recently have there been calls to include convergence as one of the drivers for the design of new mobile infrastructures and services. However, a systematic analysis of the idea of ICT convergence is still missing. Thus, based on an extensive literature review, this dissertation aims firstly to understand if there is space for a more theoretical development of this concept in the information infrastructure literature. Secondly, it provides an initial conceptual clarification of the ICT convergence discourse. Thirdly, it suggests a systems-theoretical unfolding of the identified core distinction between convergence and divergence, namely the convergence paradox. Finally, the role of technology in these discourses is examined. This dissertation analyses the notion of convergence and provides a systems-theoretical understanding of its dynamics from a second-order cybernetics perspective. The theoretical framework of this study is based on Niklas Luhmann's Theory of Social Systems. More specifically, it uses analytical strategies based on the work by Nils A. Andersen to understand the characteristics of convergence, eventually to unfold the convergence paradox. The empirical study investigates the convergence discourses around mobile Voice-over-IP in the UK from 2000-2009. The corpus of data encompasses 39 semi-structured interviews with telecommunications experts in the field of mobile VoIP, a wide range of documents, and direct observations from practitioners' conferences. The empirical study has been part of the EPSRC / Mobile VCE Core-5 Flexible Networks Project. This dissertation contributes to the broad multi-disciplinary literature of studies dealing with the phenomenon of ICT convergence, more specifically to that on information infrastructures. It develops a conceptual clarification of the notion of convergence. The findings of this dissertation suggest seeing convergence as a difference-reduction programme. This conceptualisation has the following consequences. Firstly, it suggests that convergence is observer-dependent. Secondly, it suggests that its counter-concept is not divergence or fragmentation but rather the maintenance of difference, i.e. control. Thirdly, it suggests that convergence has to deal with the typical unintended consequences inherent in difference-reduction programmes. Furthermore, while ICT convergence treated as difference-reduction programme challenges the existing identity of the infrastructure, the primary role of control is to maintain this difference. The dynamics between these two operations seem to lead to the emergence of further fragmentation