Search results for: Sanguk Ahn

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Ahn</title> <meta name="description" content="Search results for: Sanguk Ahn"> <meta name="keywords" content="Sanguk Ahn"> <meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=1, maximum-scale=1, user-scalable=no"> <meta charset="utf-8"> <link href="https://cdn.waset.org/favicon.ico" type="image/x-icon" rel="shortcut icon"> <link href="https://cdn.waset.org/static/plugins/bootstrap-4.2.1/css/bootstrap.min.css" rel="stylesheet"> <link href="https://cdn.waset.org/static/plugins/fontawesome/css/all.min.css" rel="stylesheet"> <link href="https://cdn.waset.org/static/css/site.css?v=150220211555" rel="stylesheet"> </head> <body> <header> <div class="container"> <nav class="navbar navbar-expand-lg navbar-light"> <a class="navbar-brand" href="https://waset.org"> <img src="https://cdn.waset.org/static/images/wasetc.png" alt="Open Science Research Excellence" title="Open Science Research Excellence" /> </a> <button class="d-block d-lg-none navbar-toggler ml-auto" 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id="custom-search-input"> <div class="input-group"> <i class="fas fa-search"></i> <input type="text" class="search-query" name="q" placeholder="Author, Title, Abstract, Keywords" value="Sanguk Ahn"> <input type="submit" class="btn_search" value="Search"> </div> </div> </form> </div> </div> <div class="row mt-3"> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Commenced</strong> in January 2007</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Frequency:</strong> Monthly</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Edition:</strong> International</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Paper Count:</strong> 2</div> </div> </div> </div> <h1 class="mt-3 mb-3 text-center" style="font-size:1.6rem;">Search results for: Sanguk Ahn</h1> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2</span> A Smart Monitoring System for Preventing Gas Risks in Indoor</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Gyoutae%20Park">Gyoutae Park</a>, <a href="https://publications.waset.org/abstracts/search?q=Geunjun%20Lyu"> Geunjun Lyu</a>, <a href="https://publications.waset.org/abstracts/search?q=Yeonjae%20Lee"> Yeonjae Lee</a>, <a href="https://publications.waset.org/abstracts/search?q=Jaheon%20Gu"> Jaheon Gu</a>, <a href="https://publications.waset.org/abstracts/search?q=Sanguk%20Ahn"> Sanguk Ahn</a>, <a href="https://publications.waset.org/abstracts/search?q=Hiesik%20Kim"> Hiesik Kim</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this paper, we propose a system for preventing gas risks through the use of wireless communication modules and intelligent gas safety appliances. Our system configuration consists of an automatic extinguishing system, detectors, a wall-pad, and a microcomputer controlled micom gas meter to monitor gas flow and pressure as well as the occurrence of earthquakes. The automatic fire extinguishing system checks for both combustible gaseous leaks and monitors the environmental temperature, while the detector array measures smoke and CO gas concentrations. Depending on detected conditions, the micom gas meter cuts off an inner valve and generates a warning, the automatic fire-extinguishing system cuts off an external valve and sprays extinguishing materials, or the sensors generate signals and take further action when smoke or CO are detected. Information on intelligent measures taken by the gas safety appliances and sensors are transmitted to the wall-pad, which in turn relays this as real time data to a server that can be monitored via an external network (BcN) connection to a web or mobile application for the management of gas safety. To validate this smart-home gas management system, we field-tested its suitability for use in Korean apartments under several scenarios. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=gas%20sensor" title="gas sensor">gas sensor</a>, <a href="https://publications.waset.org/abstracts/search?q=leak" title=" leak"> leak</a>, <a href="https://publications.waset.org/abstracts/search?q=gas%20safety" title=" gas safety"> gas safety</a>, <a href="https://publications.waset.org/abstracts/search?q=gas%20meter" title=" gas meter"> gas meter</a>, <a href="https://publications.waset.org/abstracts/search?q=gas%20risk" title=" gas risk"> gas risk</a>, <a href="https://publications.waset.org/abstracts/search?q=wireless%20communication" title=" wireless communication "> wireless communication </a> </p> <a href="https://publications.waset.org/abstracts/31021/a-smart-monitoring-system-for-preventing-gas-risks-in-indoor" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/31021.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">414</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">1</span> A Novel PWM/PFM Controller for PSR Fly-Back Converter Using a New Peak Sensing Technique</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Sanguk%20Nam">Sanguk Nam</a>, <a href="https://publications.waset.org/abstracts/search?q=Van%20Ha%20Nguyen"> Van Ha Nguyen</a>, <a href="https://publications.waset.org/abstracts/search?q=Hanjung%20Song"> Hanjung Song</a> </p> <p class="card-text"><strong>Abstract:</strong></p> For low-power applications such as adapters for portable devices and USB chargers, the primary side regulation (PSR) fly-back converter is widely used in lieu of the conventional fly-back converter using opto-coupler because of its simpler structure and lower cost. In the literature, there has been studies focusing on the design of PSR circuit; however, the conventional sensing method in PSR circuit using RC delay has a lower accuracy as compared to the conventional fly-back converter using opto-coupler. In this paper, we propose a novel PWM/PFM controller using new sensing technique for the PSR fly-back converter which can control an accurate output voltage. The conventional PSR circuit can sense the output voltage information from the auxiliary winding to regulate the duty cycle of the clock that control the output voltage. In the sensing signal waveform, there has two transient points at time the voltage equals to Vout+VD and Vout, respectively. In other to sense the output voltage, the PSR circuit must detect the time at which the current of the diode at the output equals to zero. In the conventional PSR flyback-converter, the sensing signal at this time has a non-sharp-negative slope that might cause a difficulty in detecting the output voltage information since a delay of sensing signal or switching clock may exist which brings out an unstable operation of PSR fly-back converter. In this paper instead of detecting output voltage at a non-sharp-negative slope, a sharp-positive slope is used to sense the proper information of the output voltage. The proposed PRS circuit consists of a saw-tooth generator, a summing circuit, a sample and hold circuit and a peak detector. Besides, there is also the start-up circuit which protects the chip from high surge current when the converter is turned on. Additionally, to reduce the standby power loss, a second mode which operates in a low frequency is designed beside the main mode at high frequency. In general, the operation of the proposed PSR circuit can be summarized as following: At the time the output information is sensed from the auxiliary winding, a saw-tooth signal from the saw-tooth generator is generated. Then, both of these signals are summed using a summing circuit. After this process, the slope of the peak of the sensing signal at the time diode current is zero becomes positive and sharp that make the peak easy to detect. The output of the summing circuit then is fed into a peak detector and the sample and hold circuit; hence, the output voltage can be properly sensed. By this way, we can sense more accurate output voltage information and extend margin even circuit is delayed or even there is the existence of noise by using only a simple circuit structure as compared with conventional circuits while the performance can be sufficiently enhanced. Circuit verification was carried out using 0.35渭m 700V Magnachip process. The simulation result of sensing signal shows a maximum error of 5mV under various load and line conditions which means the operation of the converter is stable. As compared to the conventional circuit, we achieved very small error only used analog circuits compare with conventional circuits. In this paper, a PWM/PFM controller using a simple and effective sensing method for PSR fly-back converter has been presented in this paper. The circuit structure is simple as compared with the conventional designs. The gained results from simulation confirmed the idea of the design <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=primary%20side%20regulation" title="primary side regulation">primary side regulation</a>, <a href="https://publications.waset.org/abstracts/search?q=PSR" title=" PSR"> PSR</a>, <a href="https://publications.waset.org/abstracts/search?q=sensing%20technique" title=" sensing technique"> sensing technique</a>, <a href="https://publications.waset.org/abstracts/search?q=peak%20detector" title=" peak detector"> peak detector</a>, <a href="https://publications.waset.org/abstracts/search?q=PWM%2FPFM%20control" title=" PWM/PFM control"> PWM/PFM control</a>, <a href="https://publications.waset.org/abstracts/search?q=fly-back%20converter" title=" fly-back converter"> fly-back converter</a> </p> <a href="https://publications.waset.org/abstracts/32180/a-novel-pwmpfm-controller-for-psr-fly-back-converter-using-a-new-peak-sensing-technique" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/32180.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">338</span> </span> </div> </div> </div> </main> <footer> <div id="infolinks" class="pt-3 pb-2"> <div class="container"> <div style="background-color:#f5f5f5;" class="p-3"> <div class="row"> <div class="col-md-2"> <ul class="list-unstyled"> About <li><a href="https://waset.org/page/support">About Us</a></li> <li><a href="https://waset.org/page/support#legal-information">Legal</a></li> <li><a target="_blank" rel="nofollow" href="https://publications.waset.org/static/files/WASET-16th-foundational-anniversary.pdf">WASET celebrates its 16th foundational anniversary</a></li> </ul> </div> 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Search results for: Sanguk Ahn