Mesmerizer: A Effective Tool for a Complete Peer-to-Peer Software Development Life-cycle

In this paper we present what are, in our experience, the best practices in Peer-To-Peer(P2P) application development and how we combined them in a middleware platform called Mesmerizer. We explain how simulation is an integral part of the development process and not just an assessment tool. We then present our component-based event-driven framework for P2P application development, which can be used to execute multiple instances of the same application in a strictly controlled manner over an emulated network layer for simulation/testing, or a single application in a concurrent environment for deployment purpose. We highlight modeling aspects that are of critical importance for designing and testing P2P applications, e.g. the emulation of Network Address Translation and bandwidth dynamics. We show how our simulator scales when emulating low-level bandwidth characteristics of thousands of concurrent peers while preserving a good degree of accuracy compared to a packet-level simulator

Engine performance characteristics and evaluation of variation in the length of intake plenum

In the engine with multipoint fuel injection system using electronically controlled fuel injectors has an intake manifold in which only the air flows and, the fuel is injected into the intake valve. Since the intake manifolds transport mainly air, the supercharging effects of the variable length intake plenum will be different from carbureted engine. Engine tests have been carried out with the aim of constituting a base study to design a new variable length intake manifold plenum. The objective in this research is to study the engine performance characteristics and to evaluate the effects of the variation in the length of intake plenum. The engine test bed used for experimental work consists of a control panel, a hydraulic dynamometer and measurement instruments to measure the parameters of engine performance characteristics. The control panel is being used to perform administrative and management operating system. Besides that, the hydraulic dynamometer was used to measure the power of an engine by using a cell filled with liquid to increase its load. Thus, measurement instrument is provided in this test to measure the as brake torque, brake power, thermal efficiency and specific fuel consumption. The results showed that the variation in the plenum length causes an improvement on the engine performance characteristics especially on the fuel consumption at high load and low engine speeds which are put forward the system using for urban roads. From this experiment, it will show the behavior of engine performance

Unattended network operations technology assessment study. Technical support for defining advanced satellite systems concepts

The results are summarized of an unattended network operations technology assessment study for the Space Exploration Initiative (SEI). The scope of the work included: (1) identified possible enhancements due to the proposed Mars communications network; (2) identified network operations on Mars; (3) performed a technology assessment of possible supporting technologies based on current and future approaches to network operations; and (4) developed a plan for the testing and development of these technologies. The most important results obtained are as follows: (1) addition of a third Mars Relay Satellite (MRS) and MRS cross link capabilities will enhance the network's fault tolerance capabilities through improved connectivity; (2) network functions can be divided into the six basic ISO network functional groups; (3) distributed artificial intelligence technologies will augment more traditional network management technologies to form the technological infrastructure of a virtually unattended network; and (4) a great effort is required to bring the current network technology levels for manned space communications up to the level needed for an automated fault tolerance Mars communications network

A critical analysis of research potential, challenges and future directives in industrial wireless sensor networks

In recent years, Industrial Wireless Sensor Networks (IWSNs) have emerged as an important research theme with applications spanning a wide range of industries including automation, monitoring, process control, feedback systems and automotive. Wide scope of IWSNs applications ranging from small production units, large oil and gas industries to nuclear fission control, enables a fast-paced research in this field. Though IWSNs offer advantages of low cost, flexibility, scalability, self-healing, easy deployment and reformation, yet they pose certain limitations on available potential and introduce challenges on multiple fronts due to their susceptibility to highly complex and uncertain industrial environments. In this paper a detailed discussion on design objectives, challenges and solutions, for IWSNs, are presented. A careful evaluation of industrial systems, deadlines and possible hazards in industrial atmosphere are discussed. The paper also presents a thorough review of the existing standards and industrial protocols and gives a critical evaluation of potential of these standards and protocols along with a detailed discussion on available hardware platforms, specific industrial energy harvesting techniques and their capabilities. The paper lists main service providers for IWSNs solutions and gives insight of future trends and research gaps in the field of IWSNs

Towards Developing a Travel Time Forecasting Model for Location-Based Services: a Review

Travel time forecasting models have been studied intensively as a subject of Intelligent Transportation Systems (ITS), particularly in the topics of advanced traffic management systems (ATMS), advanced traveler information systems (ATIS), and commercial vehicle operations (CVO). While the concept of travel time forecasting is relatively simple, it involves a notably complicated task of implementing even a simple model. Thus, existing forecasting models are diverse in their original formulations, including mathematical optimizations, computer simulations, statistics, and artificial intelligence. A comprehensive literature review, therefore, would assist in formulating a more reliable travel time forecasting model. On the other hand, geographic information systems (GIS) technologies primarily provide the capability of spatial and network database management, as well as technology management. Thus, GIS could support travel time forecasting in various ways by providing useful functions to both the managers in transportation management and information centers (TMICs) and the external users. Thus, in developing a travel time forecasting model, GIS could play important roles in the management of real-time and historical traffic data, the integration of multiple subsystems, and the assistance of information management. The purpose of this paper is to review various models and technologies that have been used for developing a travel time forecasting model with geographic information systems (GIS) technologies. Reviewed forecasting models in this paper include historical profile approaches, time series models, nonparametric regression models, traffic simulations, dynamic traffic assignment models, and neural networks. The potential roles and functions of GIS in travel time forecasting are also discussed.

Topology overlays for dedicated protection Ethernet LAN services in advanced SONET/SDH networks

The explosion of information technology (IT) services coupled with much-increased personal and scientific computing capabilities has resulted in great demand for more scalable and reliable networking services. Along these lines, carriers have spent large sums to transition their legacy\u27 SONET/SDH voice-based networking infrastructures to better support client-side Ethernet data interfaces, i.e., next-generation SONET/SDH (NGS). In particular, a key addition here has been the new virtual concatenation (VCAT) feature which supports inverse multiplexing to \u27split\u27 larger connection requests in to a series of independently-routed \u27sub-connections\u27. As these improved infrastructures have been deployed, the design of new Ethernet over SONET/SDH (EoS) services has become a key focus area for carriers, i.e., including point-to-point and multi-point services. In light of the above, this thesis focuses on the study of improved multi-point EoS schemes in NGS networks, i.e., to provision robust \u27virtual LAN\u27 capabilities over metro and wide-area domains. Indeed, as services demands grow, survivability considerations are becoming a key concern. Along these lines, the proposed solution develops novel multi-tiered (partial) protection strategies. Specifically, graph-theoretic algorithms are first proposed to interconnect multi-point node groups using bus and minimum spanning tree (MST) overlays. Next, advanced multi-path routing schemes are used to provision and protect these individual overlay connections using the inverse-multiplexing capabilities of NGS. Finally, post-fault restoration features are also added to handle expanded failure conditions, e.g., multiple failures. The performances of the proposed multi-point EoS algorithms developed in this research are gauged using advanced software-based simulation in the OPNET ModelerTM environment. The findings indicate that both the bus and MST overlays give very good performance in terms of request blocking and carried load. However, the MST-based overlays slightly outperform the bus-based overlays as they allow more efficient topology designs. In addition, the incorporation of dynamic load state information in the selection of bus and/or MST overlays is also very beneficial as opposed to just using static hop count state. Furthermore, inverse-multiplexing is highly-effective, yielding notably higher carried loads when coupled with load-balancing sub-connection routing. Finally, results also show that post-fault restoration is also a very effective means of boosting EoS LAN throughputs for partially-protected demands, consistently matching the reliability of full-protection setups.\u2

ZigBee-Based wireless sensor network topologies using one and multiple coordinators

Wireless Sensor Networks (WSN) have been a cost-effective and feasible solution for a wide range of applications, such as communications infrastructure, traffic networks, telecommunications systems, military operations and so forth. IEEE804.15.4 ZigBee network model is ideally suited to the constraints of WSN in terms of bandwidth, processing power and battery capacity. This paper investigated tree and mesh routing in WSN with multiple coordinators and the failure of single coordinator using OPNET Modeler v14 which is an efficient computational platform for data networks simulation. Throughput, delay, traffic received, MAC Load are studied in this system and the results showed that tree routing was better suited for WSN than mesh routing and mobility of end node in multiple coordinator network was the best

Simulation and Evaluation of Wired and Wireless Networks with NS2, NS3 and OMNET++

Communication systems are emerging rapidly with the revolutionary growth in terms of networking protocols, wired and wireless technologies, user applications and other IEEE standards. Numbers of industrial as well as academic organizations around the globe are bringing in light new innovations and ideas in the field of communication systems. These innovations and ideas require intense evaluation at initial phases of development with the use of real systems in place. Usually the real systems are expensive and not affordable for the evaluation. In this case, network simulators provide a complete cost-effective testbed for the simulation and evaluation of the underlined innovations and ideas. In past, numerous studies were conducted for the performance evaluation of network simulators based on CPU and memory utilization. However, performance evaluation based on other metrics such as congestion window, throughput, delay, packet delivery ratio and packet loss ratio was not conducted intensively. In this thesis, network simulators such as NS2, NS3 and OMNET++ will be evaluated and compared for wired and wireless networks based on congestion window, throughput, delay, packet delivery and packet loss ratio. In the theoretical part, information will be provided about the wired and wireless networks and mathematical interpretation of various components used for these networks. Furthermore, technical details about the network simulators will be presented including architectural design, programming languages and platform libraries. Advantages and disadvantages of these network simulators will also be highlighted. In the last part, the details about the experiments and analysis conducted for wired and wireless networks will be provided. At the end, findings will be concluded and future prospects of the study will be advised.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format