No. 1 (2012)
Published:
2012-03-30
ARTICLES FROM THIS ISSUE
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Design and Development of a UDP-Based Connection-Oriented Multi-Stream One-to-Many Communication Protocol
Abstract
A communication protocol is a set of rules defined formally that describes the format of digital messages and the rules for exchanging those messages in or between computing systems. The Internet Protocol Suite used for communications throughout the Internet uses encapsulation to provide a way of abstracting protocols and services. This abstraction is grouped into layers of general functionality. For protocols on the transmission layer, many choices exist. But while popular protocols such as TCP, UDP and SCTP do provide connection oriented communication offering reliability, ordering and data integrity, solutions that offer such connections from one point to multiple endpoints are still limited. TCP only supports point-to-point communication and SCTP offers multi-homing functionality, but the transmission is still limited to two logical endpoints. In this paper we use the simple, stateless, transmission model of UDP in order to provide TCP-like services for one-to-many communication that is not limited to just multi-homing or other particular solutions. The protocol supports reliable communication from one endpoint to multiple endpoints in different transmission modes. In order to make it easier for developers to customize the protocol to their needs and possibly extend/modify it in order to create new variants from it, the protocol is developed in user space. Because of this design restriction performance wasn’t the main objective of our work, but rather the ease of customization and experimentation with new protocol variants. The protocol was implemented in the C++ programming language using classes with virtual members. New variants of components, such as packet retransmission, can easily be implemented without changing the whole code base.
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Towards an Agent-Based Augmented Cloud
Abstract
In the paper an agent-based framework deployed in hybrid cluster and volunteer computing environment is presented. It utilizes two concepts proposed by the authors: Augmented Cloud and Agent Platform as a Service (AgPaaS). Both concepts are discussed in the context of Cloud Computing as defined by NIST. The key idea of the presented solution is to span the cloud (i.e., computing infrastructure) beyond the data center borders by utilizing web browsers as computational workers. The feasibility of the approach was demonstrated by two prototypes: the first one was based on Java Applets and Adobe Flash, whereas the second one on Microsoft Silverlight. The prototypes were next used to perform simple experiments, mainly related to scalability issues. Selected results from the experiments are discussed in the final part of the paper.
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Design and Implementation of an Embedded System for Ambulatory Cardiac Monitoring
Abstract
Cardiac monitoring in the environment of the subject is one of the major fields of telemedicine. In this paper we present a prototype of embedded system for acquisition, storage, display on LCD or PC and transfer via GSM alarm warning in case of arrhythmias, which allows a great opportunity for rapid intervention of the physician. In terms of hardware, we have designed and implemented our system with a modular approach to facilitate development and debugging. Thus the system comprises three modules: analog module, digital module microcontroller-based for certain pretreatment, and a GSM communication module. Of course, there is appropriate software behind the material described. The system has the following features: low cost, ease to implement and versatility.
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Secure-Sim-G: Security-Aware Grid Simulator – Basic Concept and Structure
Abstract
Task scheduling and resource allocation are the key issues for computational grids. Distributed resources usually work at different autonomous domains with their own access and security policies that impact successful job executions across the domain boundaries. In this paper we present a security-aware grid simulator Secure-Sim-G, which facilitates the evaluation of the different scheduling heuristics under various scheduling criteria in several grid scenarios defined by the security conditions, grid size and system dynamics. The simulator allows the flexible activation or inactivation of all of the scheduling criteria and modules, which makes the application well adapted to the proper illustration of the different realistic scenarios and avoids the possible restriction to the specific scheduling resolution methods. The simulation results and traces may be graphically represented and stored at the server and can retrieved in different formats such as spreadsheets or pdf files.
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An Experiment on Multi-Video Transmission with Multipoint Tiled Display Wall
Abstract
In order to realize realistic remote communication between multipoint remote places via the Internet, displaying the appearance of remote participants by transmission of a video streaming with the large-sized display system is effective. However, the display of video streaming with sufficient quality is difficult because the specification of a commercial projector and large-sized display equipment is low-resolution. In order to these issues, we focus on the tiled display wall technology which configure effective wide-area screen system with two or more LCD panels and tried to display a highresolution video streaming on the large-scale display environment. In this paper, we have constructed remote communication environment with tiled display wall in multipoint sites and have conducted experiment in order to study the possibility of realizing realistic remote communication with multi-video streaming. As these results, these video streaming from each site have been shown to display more high-quality than magnified view of video image by a single small camera. Moreover, we have measured the network throughput performance for each transmitted and received video streaming in this envi- ronment. From measurement results, the steady throughput performance has been gained at the case of each transmitted and received video streaming.
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Video Transmission Using Network Coding
Abstract
Network coding is a new technique in the field of information theory and coding theory. This emerging technique offers great benefits in the communication networks such as increased throughput and energy savings. In this paper, we evaluate network coding for video transmission scenarios. In these scenarios, the source nodes encode the video packets, while the intermediate nodes implement network coding before forwarding the encoded packets to the end nodes. Finally, the end nodes decode the received packets in order to recovery the original video. H.264/MPEG-4 AVC is used as the video compression standard in this work. We have used the network simulator (NS-2) for our simulations. Our results show that network coding improves the system throughput, reduces the packet loss and improves the video quality in the end nodes.
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QRouteMe: A Multichannel Information System to Ensure Rich User-Experiences in Exhibits and Museums
Abstract
In this article the QRouteMe system is presented. QRouteMe is a multichannel information system built to ensure rich user experiences in exhibits and museums. The system starts from basic information about a particular exhibit or museum while delivering a wide user experience based on different distribution channels. The organization of the systems’ components allow to build different solutions that can be simultaneously delivered on different media. A wide range of media from touch-screen installations to portable devices like smartphones have been used. The used devices can communicate each others to increase the usability and the user experience for the visitors. Another important feature of the system is the definition of an inexpensive auto-localization system based on fiduciary marks distributed all around the building. In this article the system is presented from an architectural and functional point of view. A case study and analysis of experimental results are also provided in a real environment where the system was deployed.
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Component-Based Architecture for Systems, Services and Data Integration in Support for Criminal Analysis
Abstract
Criminal analysis processes is based on heterogeneous data processing. To support it, analysts utilize a large set of specialized tools, however they are usually designed to solve a particular problem are often incompatible with other existing tools and systems. Therefore, to fully leverage the existing supporting tools, their technological integration is required. In this paper we present original approach for integrating systems based on the component-driven paradigm. Firstly, a problem of supporting criminal analysis is described with a strong emphasis on the heterogeneity issues. Secondly, some theoretical information about integration is depicted followed by the details of the proposed architecture. Finally, the technological assumptions are discussed and prototype integration based on proposed concept is overviewed. om the experiments are discussed in the final part of the paper.
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Recognizing Sets in Evolutionary Multiobjective Optimization
Abstract
Among Evolutionary Multiobjective Optimization Algorithms (EMOA) there are many which find only Paretooptimal solutions. These may not be enough in case of multimodal problems and non-connected Pareto fronts, where more information about the shape of the landscape is required. We propose a Multiobjective Clustered Evolutionary Strategy (MCES) which combines a hierarchic genetic algorithm consisting of multiple populations with EMOA rank selection. In the next stage, the genetic sample is clustered to recognize regions with high density of individuals. These regions are occupied by solutions from the neighborhood of the Pareto set. We discuss genetic algorithms with heuristic and the concept of well-tuning which allows for theoretical verification of the presented strategy. Numerical results begin with one example of clustering in a single-objective benchmark problem. Afterwards, we give an illustration of the EMOA rank selection in a simple two-criteria minimization problem and provide results of the simulation of MCES for multimodal, multi-connected example. The strategy copes with multimodal problems without losing local solutions and gives better insight into the shape of the evolutionary landscape. What is more, the stability of solutions in MCES may be analyzed analytically.
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Modeling and Simulation of a Vehicle Suspension with Variable Damping versus the Excitation Frequency
Abstract
In this work, three types of vehicle suspensions were considered and modeled as follows: oil damper mounted in parallel with a compression helical spring, for which a Kelvin-Voigt model, consisted of a dashpot and an elastic element connected in parallel is considered; colloidal damper without attached compression helical spring, for which a Maxwell model, consisted of a dashpot and an elastic element connected in series is considered; and colloidal damper mounted in parallel with a compression helical spring, for which a standard linear model, consisted of a Maxwell unit connected in parallel with an elastic element is considered. Firstly, the vibration transmissibility from the rough road to the vehicle’s body for all these suspensions was determined under the constraint that damping varies versus the excitation frequency. Then, the optimal damping and stiffness ratios were decided in order to minimize the transmissibility of vibration from the rough pavement to the vehicle’s body.
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The Application of Neural Networks to the Process of Gaining and Consolidating the Knowledge
Abstract
The e-learning course is one of the most efficient and promising didactic policies. It must be grounded on the revision because it was proved that it enhances the longterm memory. However, human mind is not a uniform phenomenon. Each man memorizes and learns in a different manner. The purpose of the intelligent e-learning system presented in this paper is to teach orthography and this system is based on the multilayer neural network. Such structure enables a learner to adjust the crucial period between revisions to personal learning habits and policy.
