19 research outputs found

    Developing a Framework for Effective Network Capacity Planning

    Get PDF
    As Internet traffic continues to grow exponentially, developing a clearer understanding of, and appropriately measuring, network's performance is becoming ever more critical. An important challenge faced by the Information Resources Directorate (IRD) at the Johnson Space Center in this context remains not only monitoring and maintaining a secure network, but also better understanding the capacity and future growth potential boundaries of its network. This requires capacity planning which involves modeling and simulating different network alternatives, and incorporating changes in design as technologies, components, configurations, and applications change, to determine optimal solutions in light of IRD's goals, objectives and strategies. My primary task this summer was to address this need. I evaluated network-modeling tools from OPNET Technologies Inc. and Compuware Corporation. I generated a baseline model for Building 45 using both tools by importing "real" topology/traffic information using IRD's various network management tools. I compared each tool against the other in terms of the advantages and disadvantages of both tools to accomplish IRD's goals. I also prepared step-by-step "how to design a baseline model" tutorial for both OPNET and Compuware products

    Modeling a Wireless Network for International Space Station

    Get PDF
    This paper describes the application of wireless local area network (LAN) simulation modeling methods to the hybrid LAN architecture designed for supporting crew-computing tools aboard the International Space Station (ISS). These crew-computing tools, such as wearable computers and portable advisory systems, will provide crew members with real-time vehicle and payload status information and access to digital technical and scientific libraries, significantly enhancing human capabilities in space. A wireless network, therefore, will provide wearable computer and remote instruments with the high performance computational power needed by next-generation 'intelligent' software applications. Wireless network performance in such simulated environments is characterized by the sustainable throughput of data under different traffic conditions. This data will be used to help plan the addition of more access points supporting new modules and more nodes for increased network capacity as the ISS grows

    Learning Module on Electric Motors Modeling, Control, and Testing (LM-EMMCT)

    Get PDF
    The objective of this paper is to develop and integrate a learning module on Electric Motors Modeling, Control and Testing (EMMCT) into the Electrical Engineering Technology (EET) and Mechanical Engineering Technology (MET) programs. Preparing future engineers to work in highly automated production requires proper education and training in mechatronics theory and applications. Although Engineering Technology programs at various universities offer various courses related to the controls, electrical motors, and automation, they are not including the same methods when it comes to the selection of appropriate electrical motor for a specific application in mechatronic system. MET student do have exposure to the electrical systems in the various courses that are offered at their lower division level courses. However, these methods have to be further emphasized and applied in the upper level courses as well. This paper will present one such application and a learning module that is focused on the Electric Motors Modeling, Control and Testing (EMMCT). This module can be integrated in various controls, mechatronics, robotics, senior design and capstone courses

    Delivery of Hands-On Technical Courses Through Real-Time Distance Learning

    Get PDF
    It is generally believed that it is too challenging to deliver technical laboratory courses using distance learning technologies. The focus of this research was to develop strategies that may be used to address these challenges. A research team composed of faculty from several universities and community colleges explored what might be needed to make these types of technical laboratory course instruction possible using distance learning technologies. The team explored delivering a microcontroller embedded systems design course through audio-visual distance learning technologies. The team\u27s research and development activities are discussed. These include focuses on the technical training equipment that had to be designed to support the course\u27s microcontroller technologies curriculum and laboratory modules, instructional support videos, and the design of an electronic server system to support this instruction. Also discussed will be the findings from the faculty of other colleges and universities who received professional development training from the research team on teaching microcontroller technology courses using distance learning technologies

    An Initial Look at Robotics-based Initiatives to Engage Girls in Engineering

    Get PDF
    Over the past 10 years, the use of robotic kits in K-12 Science, Technology, Engineering, and Math (STEM) initiatives as well as undergraduate engineering education has increased significantly. However, a survey of students in grades 9–12 indicated that only 2–3% of women in high school express an intention to study engineering; conversely, 16% of high school men declared that they plan to pursue an engineering degree [1]. In this paper, the authors present an initial review of published literature regarding the use of robotics in schools to identify cases where robotic kits have been used to engage girls in STEM learning and to discuss how robotics has been used or could be used to positively influence outcomes of girls’ knowledge, interests, self-efficacy, and attitudes related to careers in engineering

    Dissemination of Microprocessor Courses Through Classroom and Interactive Cyber-Enabled Technologies

    Get PDF
    The project is in the middle stages of the implementation. There seems to be a positive attitude of learning and using of the training system and curriculum package by all project staffs. Microchip, Inc. and microEngineering Labs, Inc. have donated supplies to support the hardware and software development for this project. The next objectives are team training, recruitment of interested trainees/teachers to participate in training for summers 2014, and assess the effectiveness of the implementations with teachers and students. Photo 2 is the project logo that describes all the concepts of this project

    Gamma rays induced enhancement in the phytonutrient capacities of tomato (Solanum Lycopersicum L.)

    Get PDF
    One of the most important problems for the field-grown Ayaş tomato (Solanum lycopersicum Ayas population), which is preferred for consumption in Central Anatolia because of its aromatic taste, is that the shelf life is short because of insufficient fruit firmness. Therefore, a study was initiated to develop high-quality lines and variety candidates through mutation breeding in the current Ayaş population. In this study, the effective mutation dose (EMD50) was found to be 150 Gy for seeds using a Cobalt-60 gamma ray source. The main mutant population was generated by applying EMD50. During the study, mutant lines selected by following the classical mutation breeding stages were evaluated in terms of yield and quality traits (antioxidant content, total soluble solid amount, fruit firmness, Brix, etc.) starting from the M4 stage. One of our aims was to determine and improve the phytonutrient content of field-grown tomatoes. The fruits of selected lines at the M4 stage were extracted by liquid-liquid partition and accelerated solvent extraction techniques and analyzed by High Performance Liquid Chromatography (HPLC) in this study. It was found that 28 of the 29 mutant lines were significantly different from the control and mutant lines. Mutant lines 9-22, 8-90, 8-135, and 8-127 were determined to be the most promising for commercialization

    An Urn Occupancy Approach for Modeling the Energy Consumption of Distributed Beaconing

    No full text
    In past years, ultra wideband technology has attracted great attention from academia and industry for wireless personal area networks and wireless sensor networks. Maintenance of connectivity and exchange of data require an efficient way to manage the devices. Distributed beaconing defined by ECMA-368 is used to manage the network in fully distributed fashion. Distributed beaconing requires that all devices acquire a unique beacon slot, with the beacon period accessed using a slotted Aloha scheme. In this paper, we study the efficiency of distributed beaconing in the presence of k newcomer devices forming a closed system. Efficiency is measured in terms of energy consumption and network set-up delay. ECMA-368 defines two distinct phases: extension and contraction. Both phases are analyzed with particular emphasis on the extension phase by means of an absorbing Markov chain model. The main contributions of this paper are: 1) a systematic approach to model distributed beaconing by formulating two equivalent urn occupancy problems of the extension and contraction phases; 2) the use of exponential generating functions to obtain closed form expressions of the transition probabilities of the absorbing Markov chain; and 3) comparison with computer simulations based on Opnet modeling and with the preexisting literature.JRC.G.6-Security technology assessmen

    Toward actively defending from DOS attacks in UMTS-WLAN

    No full text
    A wireless network is more vulnerable to denial of service (DoS) attacks than a wired one. In this paper we propose a new DoS defense scheme toward actively resisting DoS attacks. A mobile terminal generates an authorized anonymous ID (AAI) using its true ID, and assigns its true ID with the produced AAI. Using an AAI, a legitimate mobile terminal will be authenticated by the wireless network, however, its true ID is concealed, and it ‘disappears’ to potential attackers. This method can be used to defend several kinds of DoS attacks at the same time. Additionally it can also be used to alleviate other kinds of security threats in wireless networks, such as eavesdropping. We demonstrate our proposed method in detail in a new application network: UMTS-WLAN (Universal Mobile Telecommunication Systems - Wireless Local Area Network) network, and provide some simulation results in OPNET 10.0 A environment
    corecore