• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1716-1717
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• 2007

In this paper, a second order fuzzy sliding mode control that combines with a adaptive self-regulating technique is proposed for a nonlinear system with unknown dynamics. The chattering effect that is a representative disadvantage of the sliding mode control is avoided by using the second order sliding mode control instead of the first order sliding mode control. The proposed sub-controller is composed of the equivalent control that is approximated by an online rule regulation sheme and the hitting control that is used to constrain the states of the sub-system to maintain on the sub-sliding surface and used to guarantee the system robustness. Simulation results are presented to show the effectiveness of the proposed controller

• 시스템엔지니어링학술지
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• 제5권1호
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• pp.1-6
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• 2009

Gun fire solution computed in ballistic computing unit (BCU) needs to evaluated before applying in real fire. In this paper, ballistic performance analysis method is studied for reasonable prediction or hit probability with ballistics error presentation on hitting plane. Also Gun fire solution using interacting multiple model (IMM) algorithm is analyzed through proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.468-471
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• 2003

In this paper, a second order sliding mode control that combines with a fuzzy adaptation technique is presented for a nonlinear system with unknown dynamics. The chattering effect that is a representative disadvantage of the sliding mode control is avoided by using the second order sliding mode control instead of the first order sliding mode control. The proposed controller is composed of the equivalent control that is approximated by an online adaptation scheme and the hitting control that is used to constrain the states to maintain on the sub-sliding surface and used to guarantee the system robustness. Simulation results are presented to show the effectiveness of the proposed controller.

• 한국전자거래학회지
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• 제6권2호
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• pp.87-99
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• 2001

Along with the rapid emergence of the Internet and e-commerce, online auctions are hitting the spotlights. The inconveniences found in off-line auctions, such as time and place restriction and limited number of items, are solved in the online auction. However, not so many auction sites have integrated auction information systems, which monitor the present status of auctions, resulting in greater inconvenience for the online auction users. Moreover, there is no auction site that suggests the appropriate starting or closing price that is useful for users when they make, their bids, What the online auction users need is an auction system that can solve such problems. This study is purported for solving the problems by designing and implementing a real time auction system that applies the comparison search functions and the agent functions. In other words, an integrated database system using a bidder-oriented agent for providing information is built so that the users can search and compare the information on the item they are interested in and make a faster and more accurate purchase. Also the appropriate starting and closing prices are offered to the sellers and bidders through the integrated system for a closer and more accurate comparison and analysis of the prices. For future work, the product recommendation service, which accurately reflects the bidding patterns, and the methods for studying the multi bidding pattern will be applied to the suggested system to realize a real time auction information system that supports CRM(Customer Relationship Management) .

• 센서학회지
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• 제28권6호
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• pp.371-376
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• 2019

We have developed an acoustic resonance inspection system to inspect the welding defects in the mechanical parts fabricated using friction stir welding method. The inspection system was consisted of a DAQ board, a microphone sensor, an impact hammer, and controlled by a PC software. The system was developed to collect and analyze the sound signal generated by hitting the sample with an impact hammer to determine whether it is defective. In this study, 100% welded good samples were compared with 95%, 90%, and 85% welded samples, respectively. The variation of the completeness in welding did not affect the visual appearance in the samples. As a result of analyzing the natural frequencies of the good samples, the five natural frequency peaks were identified. In the case of the defective samples, the frequency change was observed. The welding failure detection time was fast enough to be only 0.7 seconds. Employing our welding defect inspection system to the actual industrial field will maximize the efficiency of quality inspection and thus improve the productivity.

• 한국정보시스템학회지:정보시스템연구
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• 제23권1호
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• pp.185-202
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• 2014

ERP, a typical enterprise application, helps companies to increase their productivity and to support their decision makings. ERP is composed of diverse functions that are optimized under PC environment, whereas the ERP applications on a mobile platform have many constraints such as a small screen, limited resolution, and computing power. Because all the functions of a ERP legacy system are not required for ERP on a mobile device, the core functions of the ERP system should be selected to increase system efficiency. In this study, two main methods were used; interviews and log analyses. The end users using a ERP system were interviewed for their perceptions, and log data analyses were made for the hitting number of specific ERP functions. The differences between the actual usage based on log data and users' cognitive preferences about ERP functions were analysed. Finally, the functional differences between users' perception and actual usage were suggested for some practical implications.

• Journal of Multimedia Information System
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• 제3권3호
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• pp.63-68
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• 2016

Environmental downtime produces a significant cost to organizations and makes them unable to do business because what happens in the data center affects everyone. In addition, the amount of electrical energy consumed by data centers increases with the amount of computing power installed. Installation of physical Information Technology and facilities related to environmental concerns, such as monitoring temperature, humidity, power, flood, smoke, air flow, and room entry, is the most proactive way to reduce the unnecessary costs of expensive hardware replacement or unplanned downtime and decrease energy consumed by servers. In this paper, we present remote system for monitoring datacenter implementing using open-source hardware platforms; Arduino, Raspberry Pi, and the Gobetwino. The sensed data displayed through Arduino are transferred using Gobetwino to the nearest host server such as temperature, humidity and distance every time an object hitting another object or a person coming in entrance. The raspberry Pi records the sensed data at the remote location. The objective of collecting temperature and humidity data allows monitoring of the server's health and getting alerts if things start to go wrong. When the temperature hits $50^{\circ}C$, the supervisor at remote headquarters would get a SMS, and then they would take appropriate actions to reduce electrical costs and preserve functionality of servers in data centers.

• 방송공학회논문지
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• 제20권3호
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• pp.440-448
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• 2015

논문에서는 지능형 차량에 적용하기 위해 보행자의 의도를 분석하여 보행자와의 사고를 미연에 방지하는 시스템을 제안한다. 제안하는 시스템은 블랙박스 영상으로부터 실시간으로 보행자를 검출하고, 소실점을 바탕으로 한 보행자의 상대 위치와 옵티컬 플로우를 이용한 움직임 방향 정보를 추출한다. 이러한 보행자의 정보와 차량의 현재 속도에 기반한 차량 정지 거리를 이용하여 보행자와의 충돌 위험도를 파악하는 퍼지 로직을 구현하였다. 최종적으로 퍼지 로직의 출력 정보인 충돌 위험도에 따라 운전자에게 경고를 주도록 하였다. 마지막으로 실제 주행 영상을 이용하여 제안된 시스템의 성능과 한계점을 분석하였다.

• 융합보안논문지
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• 제18권5_2호
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• pp.35-41
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• 2018

육군은 합동개념과 연계하여 지상전장개념을 발전시키고 있으며 이를 지원하기 위해 기반통신체계로서 TICN을 도입하였다. TICN을 이용하여 전송속도의 향상 및 통달거리를 확대하였으며, 이를 통해 감시체계로부터 타격체계까지 실시간 혹은 근실시간으로 정보 유통이 가능하도록 네트워크 중심 작전환경 조성에 힘쓰고 있다. 그러나 TICN은 전장상황에서의 여러 가지 우발상황으로 인해 발생할 수 있는 네트워크 측면에서의 제한사항을 극복하기에는 미흡한 부분이 있다. 이에 본 논문에서는 전장상황에서 발생 가능한 상황에 따른 통신 제한에 대해 파악하고 이를 극복하기 위한 고려사항에 대해 연구하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 V
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• pp.2875-2878
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• 2003

In this paper, we propose an EEG-based mental state prediction method during a mental tasks. In the experimental task, a subject goes through the process of responding to visual stimulus, understanding the given problem, controlling hand motions, and hitting a key. Considering the subject's varying brain activities, we model subjects' mental states with defining selection time. EEG signals from four subjects were recorded while they performed three mental tasks. Feature vectors defined by these representations were classified with a standard, feed-forward neural network trained via the error back-propagation algorithm. We expect that the proposed detection method can be a basic technology for brain-computer interface by combining with left/right hand movement or cognitive decision discrimination methods.