This paper presents further results on the problem of establishing stability of retarded nonlinear interconnected systems comprising integral input-to-state stable subsystems. It is shown that the stability of the int...
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ISBN:
(纸本)9781424445233
This paper presents further results on the problem of establishing stability of retarded nonlinear interconnected systems comprising integral input-to-state stable subsystems. It is shown that the stability of the interconnected systems with respect to external signals can be verified by constructing Lyapunov-Krasovskii functionals explicitly whenever small-gain type conditions are satisfied. The primary result [12] is generalized in two aspects. One is to introduce a new flexibility in constructing Lyapunov-Krasovskii functionals to deal with distributed delays more effectively. The other is to cover systems involving time-varying delays in interconnecting channels.
While bandwidth management in cellular communication systems has been thoroughly examined for voice channel admission by developing several DCA (Dynamic Channel Assignment) strategies, there are a few only efforts inv...
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While bandwidth management in cellular communication systems has been thoroughly examined for voice channel admission by developing several DCA (Dynamic Channel Assignment) strategies, there are a few only efforts investigating assignment and management of multimedia enabling channels in wireless communications. However, the increasing demand for these advanced services in cellular networks such as data, MMS and video transfers raises the problem of efficient bandwidth management in terms of channel assignment meeting QoS criteria. Several algorithms for supporting QoS services have been presented in the literature based mainly on bandwidth reservation and capacity management for enabling efficient handoff over cellular networks. The goal of this paper is to develop and investigate, however, novel integral DCA algorithms for supporting data (e.g. files) and video (video viewing, video conference) transmission with Quality of Service (QoS), and their evaluation through a prototype advanced statistical simulation environment for cellular communications. Moreover, we analyze the dynamic and distributed channel allocation strategies for enabling advanced multimedia services based on signal purity measures and interference measurements. Finally, the performance of these suggested algorithms evaluated through a proposed prototype simulation environment is discussed.
There are many research efforts for improving bandwidth management in wireless communication systems based mainly on DCA (Dynamic Channel Allocation) Schemes designed and evaluated through various Simulation models wh...
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There are many research efforts for improving bandwidth management in wireless communication systems based mainly on DCA (Dynamic Channel Allocation) Schemes designed and evaluated through various Simulation models which, however, use a common simulation model architecture coming from queuing theory. Although much attention has been paid to Channel Allocation Mechanisms there are few only efforts related to the corresponding simulation models. These models consist of various critical components including network services models and the simulation model architecture organizing network events scheduling, network events handling and network performance evaluation. One of the most critical components is the event scheduling mechanism, which reflects network events as they happen in a real network and which has not been investigated in depth regarding its performance. The state of the art event scheduling mechanism called Calendar Queue (CQ) schedules events for later execution based on the corresponding time stamps of each generated event. The major drawback of this approach is that the generated events are executed only sequentially due to progressive time stamps. On the other hand, events in a real wireless network happen concurrently and so the state of the art mechanism can not reflect such conditions. The goal of this paper is to propose an alternative novel real time scheduling mechanism based on a synthesis of multitasking theory and queuing theory techniques, which could be involved in generating and investigating a new generation of event scheduling algorithms suitable for simulation modelling of cellular networks bandwidth management. This mechanism is analyzed through multitasking theory tools and is shown to face effectively the concurrent nature of the generated network events providing an efficient solution to the Calendar Queue problem.
When it comes to 3D Virtual Environments it is well known that 3D sound is of great importance to the whole interactive experience. The percept of sound is a major counterpart for the eyesight, since it describes the ...
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ISBN:
(纸本)9789898111203
When it comes to 3D Virtual Environments it is well known that 3D sound is of great importance to the whole interactive experience. The percept of sound is a major counterpart for the eyesight, since it describes the location, the momentum and the attitude towards the listener, of each surrounding entity. The sound can offer precision of spatial perception that cannot be achieved by the eye itself Thus the support of 3D surround sound of high fidelity is mandatory for a 3D Virtual platform. The evolution of Internet telephony led to the introduction of new session establishment and management protocols. The most important of them, the Session Initiation Protocol (SIP), is a robust, lightweight reliable and fast application-layer control (signaling) protocol that is highly adopted for creating, modifying and terminating sessions. This protocol can be of extreme importance in establishing audio sessions for multi-user platforms. This paper presents the work done for developing a SIP 3D spatial audio server for a multi-user virtual environments platform, called EVE, in order to support 3D spatial audio.
The physical activities of a real wireless network are represented by events which are the main components of a discrete event simulation (DES) system and are produced by its event generator during simulation time. Ea...
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The physical activities of a real wireless network are represented by events which are the main components of a discrete event simulation (DES) system and are produced by its event generator during simulation time. Each network service (e.g. voice, data and video) constitutes an event for a particular mobile user. A critical component within the simulation system, called scheduler, runs by selecting the next earliest event, executing it till completion, and returning to execute the next event. Calendar queue is the state of the art implementation of the scheduler among the most popular networking simulation tools such as ns-2. However, Calendar queue time-stamping mechanism presents drawbacks in the case of complex dynamical systems, like wireless networks, where probability of events concurrency is large. In such a case sequential time-stamping of calendar queue scheduling does not reflect real network events occurrence and generation. It should be remarked that there are very few reports if any in the literature concerning research on events scheduling mechanisms in such real time systems. On the other hand, multi-threading technology offers advanced capabilities for modelling concurrent events. The main goal of this paper is to illustrate that multithreading architectures provide the means for designing efficient schedulers in the simulation of wireless networks resource allocation but, also, several critical issues such as deadlocks, synchronization and scheduling must be effectively faced. In this paper, a stable simulation model is presented based on a novel layered thread architecture and on an alternative network event scheduling mechanism, called the Priority Queue (PQ) - Time Division Multiplexing (TDM) Layered Multithreading mechanism, which supports concurrent events as compared to the state of the art approach which supports only sequential events. Moreover, specific drawbacks of the JVM multi-threading platform such as thread execution unpredictability
The Human Protein Atlas is a rich source of location proteomics data. In this work, we present an automated approach for processing and classifying major subcellular patterns in the Atlas images. We demonstrate that t...
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ISBN:
(纸本)9781424439317
The Human Protein Atlas is a rich source of location proteomics data. In this work, we present an automated approach for processing and classifying major subcellular patterns in the Atlas images. We demonstrate that two different classification frameworks (support vector machine and random forest) are effective at determining subcellular locations; we can analyze over 3500 Atlas images with a high degree of accuracy, up to 87.5% for all of the samples and 98.5% when only considering samples in whose classification assignments we are most confident. Moreover, the features obtained in both of these frameworks are observed to be highly consistent and generalizable. Additionally, we observe that the features relating the proteins to cell markers are especially important in automated learning approaches.
Service-oriented architecture can be considered as a philosophy or paradigm in organizing and utilizing services and capabilities that may be under the control of different ownership domains. Virtualization provides a...
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Service-oriented architecture can be considered as a philosophy or paradigm in organizing and utilizing services and capabilities that may be under the control of different ownership domains. Virtualization provides abstraction and isolation of lower level functionalities, enabling portability of higher level functions and sharing of physical resources. However, dynamics, environmental conditions and increasing complexity / heterogeneity of underlying resources call for adaptive resource handling. In this view an intelligent distributed architecture that enables dynamic user management and control on network-wide resource sharing by using the service oriented architecture concept is presented. Additionally, the proposed architecture supports trading of resources that will enable the transformation of traditional business models.
In this paper, we present the implementation and analysis of our testbed considering the link quality window size (LQWS) parameter of optimized link state routing (OLSR) and better approach to mobile ad-hoc networking...
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ISBN:
(纸本)9781424440009
In this paper, we present the implementation and analysis of our testbed considering the link quality window size (LQWS) parameter of optimized link state routing (OLSR) and better approach to mobile ad-hoc networking (B.A.T.M.A.N.) protocols. We investigate the effect of mobility in the throughput of a mobile ad-hoc network (MANET). The mobile nodes move toward the destination at a regular speed. When the mobile nodes arrive at the corner, they stop for about three seconds. In our experiments, we consider two cases: only one node is moving (mobile node)and two nodes (intermediate nodes) are moving at the same time. We assess the performance of our testbed in terms of throughput, round trip time, jitter and packet loss. From our experiments, we found that throughput of TCP was improved by reducing LQWS.
Resting tremor (RT) is one of the most frequent signs of the Parkinson's disease (PD), occurring with various severities in about 75% of the patients. Current diagnosis is based on subjective clinical assessment, ...
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Resting tremor (RT) is one of the most frequent signs of the Parkinson's disease (PD), occurring with various severities in about 75% of the patients. Current diagnosis is based on subjective clinical assessment, which is not always easy to capture subtle, mild and intermittent tremors. The aim of the present study is to assess the suitability and clinical value of a computer based real-time system as an aid to diagnosis of PD, in particular the presence of RT. Five healthy subjects were asked to simulate several severities of RT in hands and feet in three static activities. The behaviour of the subjects is measured using tri-axial accelerometers, which are placed at four different positions on the body. Frequency-domain features, strongly correlated with the RT activity, are extracted from the accelerometer data. The classification of RT severity based on those features, provided accuracy 76%. The real-time system designed for efficient extraction of those features and the provision of a continuous RT severity measure is described.
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