326 research outputs found
Predication of Drug Target Interaction using Reliable Multicast Routing in Wireless Ad hoc Molecular Network
Wireless Ad hoc Molecular network consists of atoms in terms of nodes in the absence of administrative point. In this connection, there is a need to adopt molecular analogy to define the architecture. Prediction of Drug Target Interaction (DTI) is a major impact in molecular ad hoc network. Efforts were made to combine such information with data to define DTI and to construct biological space. The concept of Conditional Random Field (CRF) is used in our proposed reliable multicast routing to integrate genomic, chemical and functional data to predict DTI. Reliability of links was also maintained to increase the network performance. Based on the extensive simulation results, the proposed reliable routing protocol achieves better performance than existing schemes
Game theory analysis and modeling of sophisticated multi-collusion attack in MANETs
Mobile Adhoc Network (MANET) has been a core topic of research since the last decade.
Currently, this form of networking paradigm is increasingly being construed as an integral part of upcoming
urban applications of Internet-of-Things (IoT), consisting of massive connectivity of diverse types of nodes.
There is a significant barrier to the applicability of existing routing approaches in conventional MANETs
when integrated with IoT. This routing mismatch can lead to security risks for the MANET-based application
tied with the IoT platform. This paper examines a pragmatic scenario as a test case wherein the mobile nodes
must exchange multimedia signals for supporting real-time streaming applications. There exist two essential
security requirements viz. i) securing the data packet and ii) understanding the unpredictable behavior of the
attacker. The current study considers sophistication on the part of attacker nodes. They are aware of each
other’s identity and thereby collude to conduct lethal attacks, which is rarely reflected in existing security
modeling statistics. This research harnesses the potential modeling aspect of game theory to model the
multiple-collusion attacker scenario. It contributes towards i) modeling strategies of regular/malicious nodes
and ii) applying optimization principle using novel auxiliary information to formulate the optimal strategies.
The model advances each regular node’s capability to carry out precise computation about the opponent
player’s strategy prediction, i.e., malicious node. The simulation outcome of the proposed mathematical
model in MATLAB ascertains that it outperforms the game theory’s baseline approach
Evolutionary Robot Swarms Under Real-World Constraints
Tese de doutoramento em Engenharia Electrotécnica
e de Computadores, na especialidade de Automação e Robótica, apresentada ao Departamento de Engenharia Electrotécnica e de Computadores da Faculdade de Ciências e Tecnologia da Universidade de CoimbraNas últimas décadas, vários cientistas e engenheiros têm vindo a estudar as estratégias provenientes da natureza. Dentro das arquiteturas biológicas, as sociedades que vivem em enxames revelam que agentes simplistas, tais como formigas ou pássaros, são capazes de realizar tarefas complexas usufruindo de mecanismos de cooperação. Estes sistemas abrangem todas as condições necessárias para a sobrevivência, incorporando comportamentos de cooperação, competição e adaptação. Na “batalha” sem fim em prol do progresso dos mecanismos artificiais desenvolvidos pelo homem, a ciência conseguiu simular o primeiro comportamento em enxame no final dos anos oitenta. Desde então, muitas outras áreas, entre as quais a robótica, beneficiaram de mecanismos de tolerância a falhas inerentes da inteligência coletiva de enxames.
A área de investigação deste estudo incide na robótica de enxame, consistindo num domínio particular dos sistemas robóticos cooperativos que incorpora os mecanismos de inteligência coletiva de enxames na robótica. Mais especificamente, propõe-se uma solução completa de robótica de enxames a ser aplicada em contexto real. Nesta ótica, as operações de busca e salvamento foram consideradas como o caso de estudo principal devido ao nível de complexidade associado às mesmas. Tais operações ocorrem tipicamente em cenários dinâmicos de elevadas dimensões, com condições adversas que colocam em causa a aplicabilidade dos sistemas robóticos cooperativos. Este estudo centra-se nestes problemas, procurando novos desafios que não podem ser ultrapassados através da simples adaptação da literatura da especialidade em algoritmos de enxame, planeamento, controlo e técnicas de tomada de decisão.
As contribuições deste trabalho sustentam-se em torno da extensão do método Particle Swarm Optimization (PSO) aplicado a sistemas robóticos cooperativos, denominado de Robotic Darwinian Particle Swarm Optimization (RDPSO). O RDPSO consiste numa arquitetura robótica de enxame distribuída que beneficia do particionamento dinâmico da população de robôs utilizando mecanismos evolucionários de exclusão social baseados na sobrevivência do mais forte de Darwin. No entanto, apesar de estar assente no caso de estudo do RDPSO, a aplicabilidade dos conceitos aqui propostos não se encontra restrita ao mesmo, visto que todos os algoritmos parametrizáveis de enxame de robôs podem beneficiar de uma abordagem idêntica.
Os fundamentos em torno do RDPSO são introduzidos, focando-se na dinâmica dos robôs, nos constrangimentos introduzidos pelos obstáculos e pela comunicação, e nas suas propriedades evolucionárias. Considerando a colocação inicial dos robôs no ambiente como algo fundamental para aplicar sistemas de enxames em aplicações reais, é assim introduzida uma estratégia de colocação de robôs realista. Para tal, a população de robôs é dividida de forma hierárquica, em que são utilizadas plataformas mais robustas para colocar as plataformas de enxame no cenário de forma autónoma. Após a colocação dos robôs no cenário, é apresentada uma estratégia para permitir a criação e manutenção de uma rede de comunicação móvel ad hoc com tolerância a falhas. Esta estratégia não considera somente a distância entre robôs, mas também a qualidade do nível de sinal rádio frequência, redefinindo assim a sua aplicabilidade em cenários reais. Os aspetos anteriormente mencionados estão sujeitos a uma análise detalhada do sistema de comunicação inerente ao algoritmo, para atingir uma implementação mais escalável do RDPSO a cenários de elevada complexidade. Esta elevada complexidade inerente à dinâmica dos cenários motivaram a ultimar o desenvolvimento do RDPSO, integrando para o efeito um mecanismo adaptativo baseado em informação contextual (e.g., nível de atividade do grupo).
Face a estas considerações, o presente estudo pode contribuir para expandir o estado-da-arte em robótica de enxame com algoritmos inovadores aplicados em contexto real. Neste sentido, todos os métodos propostos foram extensivamente validados e comparados com alternativas, tanto em simulação como com robôs reais. Para além disso, e dadas as limitações destes (e.g., número limitado de robôs, cenários de dimensões limitadas, constrangimentos reais limitados), este trabalho contribui ainda para um maior aprofundamento do estado-da-arte, onde se propõe um modelo macroscópico capaz de capturar a dinâmica inerente ao RDPSO e, até certo ponto, estimar analiticamente o desempenho coletivo dos robôs perante determinada tarefa.
Em suma, esta investigação pode ter aplicabilidade prática ao colmatar a lacuna que se faz sentir no âmbito das estratégias de enxames de robôs em contexto real e, em particular, em cenários de busca e salvamento.Over the past decades, many scientists and engineers have been studying nature’s best and time-tested
patterns and strategies. Within the existing biological architectures, swarm societies revealed that
relatively unsophisticated agents with limited capabilities, such as ants or birds, were able to cooperatively
accomplish complex tasks necessary for their survival. Those simplistic systems embrace all
the conditions necessary to survive, thus embodying cooperative, competitive and adaptive behaviours.
In the never-ending battle to advance artificial manmade mechanisms, computer scientists simulated
the first swarm behaviour designed to mimic the flocking behaviour of birds in the late eighties.
Ever since, many other fields, such as robotics, have benefited from the fault-tolerant mechanism
inherent to swarm intelligence.
The area of research presented in this Ph.D. Thesis focuses on swarm robotics, which is a particular
domain of multi-robot systems (MRS) that embodies the mechanisms of swarm intelligence
into robotics. More specifically, this Thesis proposes a complete swarm robotic solution that can be
applied to real-world missions. Although the proposed methods do not depend on any particular application,
search and rescue (SaR) operations were considered as the main case study due to their
inherent level of complexity. Such operations often occur in highly dynamic and large scenarios, with
harsh and faulty conditions, that pose several problems to MRS applicability. This Thesis focuses on
these problems raising new challenges that cannot be handled appropriately by simple adaptation of
state-of-the-art swarm algorithms, planning, control and decision-making techniques.
The contributions of this Thesis revolve around an extension of the Particle Swarm Optimization
(PSO) to MRS, denoted as Robotic Darwinian Particle Swarm Optimization (RDPSO). The RDPSO
is a distributed swarm robotic architecture that benefits from the dynamical partitioning of the whole
swarm of robots by means of an evolutionary social exclusion mechanism based on Darwin’s survival-of-the-fittest.
Nevertheless, although currently applied solely to the RDPSO case study, the applicability
of all concepts herein proposed is not restricted to it, since all parameterized swarm robotic
algorithms may benefit from a similar approach The RDPSO is then proposed and used to devise the applicability of novel approaches. The fundamentals
around the RDPSO are introduced by focusing on robots’ dynamics, obstacle avoidance,
communication constraints and its evolutionary properties. Afterwards, taking the initial deployment
of robots within the environment as a basis for applying swarm robotics systems into real-world applications,
the development of a realistic deployment strategy is proposed. For that end, the population
of robots is hierarchically divided, wherein larger support platforms autonomously deploy
smaller exploring platforms in the scenario, while considering communication constraints and obstacles.
After the deployment, a way of ensuring a fault-tolerant multi-hop mobile ad hoc communication
network (MANET) is introduced to explicitly exchange information needed in a collaborative realworld
task execution. Such strategy not only considers the maximum communication range between
robots, but also the minimum signal quality, thus refining the applicability to real-world context. This
is naturally followed by a deep analysis of the RDPSO communication system, describing the dynamics
of the communication data packet structure shared between teammates. Such procedure is a
first step to achieving a more scalable implementation by optimizing the communication procedure
between robots. The highly dynamic characteristics of real-world applications motivated us to ultimate
the RDPSO development with an adaptive strategy based on a set of context-based evaluation
metrics.
This thesis contributes to the state-of-the-art in swarm robotics with novel algorithms for realworld
applications. All of the proposed approaches have been extensively validated in benchmarking
tasks, in simulation, and with real robots. On top of that, and due to the limitations inherent to those
(e.g., number of robots, scenario dimensions, real-world constraints), this Thesis further contributes
to the state-of-the-art by proposing a macroscopic model able to capture the RDPSO dynamics and,
to some extent, analytically estimate the collective performance of robots under a certain task. It is
the author’s expectation that this Ph.D. Thesis may shed some light into bridging the reality gap
inherent to the applicability of swarm strategies to real-world scenarios, and in particular to SaR operations.FCT - SFRH/BD /73382/201
Multi-Agent Systems
A multi-agent system (MAS) is a system composed of multiple interacting intelligent agents. Multi-agent systems can be used to solve problems which are difficult or impossible for an individual agent or monolithic system to solve. Agent systems are open and extensible systems that allow for the deployment of autonomous and proactive software components. Multi-agent systems have been brought up and used in several application domains
Cooperative Situation Awareness in Transportation
Intelligent Transportation Systems (ITS) became a fast moving eld of research in the last decades, in particular in the context of continuously growing mobility and a high employment of resources starting from energy and material consumption to travel time and nally the human life. As it has already been experienced in other application areas, the introduction of communications technology is able to bring a revolutionary change in structures and behaviors long-believed to be carved in stone.
The main idea behind this thesis is the usage of information not as a mere placeholder, e.g. a eld in a static message, but actively utilizing its content and dependencies. This requires an estimation of the actual worth of a single piece of information for the entity itself and the entities which are in communication range. This worth has to be the essential driver for the cooperative situation estimation. The active utilization of information and its cooperative dissemination provides the entities the opportunity to become situation aware and detect hazardous or inefficient situations early in advance.
Since information always has a degree of uncertainty which is inherent to information in the real-world problem domain, as we are confronted with in ITS, probabilistic methods will be applied to model situation-relevant information. Conditional probability distributions in state transition models make for the evolvement of the situational information with the progress of time and handle causal dependencies between situational information. Together with a utility-based decision-making process dynamic probabilistic causal decision networks provide the functionality to select optimal actions given sequences of
inaccurate and incomplete evidences.
This thesis provides concepts and strategies that push forward the exploitation of information in a cooperative way within a probabilistic framework that allows to make various kinds of decisions with maximum utility. For the evaluation of the proposed concepts, the exemplary application Cooperative Adaptive Cruise Control (CACC) has been implemented on the basis of a particle lter which is used for the situation estimation. Initial simulations provided promising results and hence constitute a solid basis for future work in the eld of Cooperative Situation Awareness in Transportation
Dagstuhl News January - December 2006
"Dagstuhl News" is a publication edited especially for the members of the Foundation "Informatikzentrum Schloss Dagstuhl" to thank them for their support. The News give a summary of the scientific work being done in Dagstuhl. Each Dagstuhl Seminar is presented by a small abstract describing the contents and scientific highlights of the seminar as well as the perspectives or challenges of the research topic
Personality Identification from Social Media Using Deep Learning: A Review
Social media helps in sharing of ideas and information among people scattered around the world and thus helps in creating communities, groups, and virtual networks. Identification of personality is significant in many types of applications such as in detecting the mental state or character of a person, predicting job satisfaction, professional and personal relationship success, in recommendation systems. Personality is also an important factor to determine individual variation in thoughts, feelings, and conduct systems. According to the survey of Global social media research in 2018, approximately 3.196 billion social media users are in worldwide. The numbers are estimated to grow rapidly further with the use of mobile smart devices and advancement in technology. Support vector machine (SVM), Naive Bayes (NB), Multilayer perceptron neural network, and convolutional neural network (CNN) are some of the machine learning techniques used for personality identification in the literature review. This paper presents various studies conducted in identifying the personality of social media users with the help of machine learning approaches and the recent studies that targeted to predict the personality of online social media (OSM) users are reviewed
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