• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.258-264
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• 2018

This paper presents application of a differential search (DS) meta-heuristic optimization algorithm for optimal operation of a micro grid system. The DS algorithm simulates the Brownian-like random-walk movement used by an organism to migrate. The micro grid system consists of a wind turbine, a diesel generator, a fuel cell, and a photovoltaic system. The wind turbine generator is modeled by considering the characteristics of variable output. Optimization is aimed at minimizing the cost function of the system, including fuel costs and maximizing fuel efficiency to generate electric power. The simulation was applied to a micro grid system only. This study applies the DS algorithm with excellence and efficiency in terms of coding simplicity, fast convergence speed, and accuracy in the optimal operation of micro grids based on renewable energy resources, and we compared its optimum value to other algorithms to prove its superiority.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.2
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• pp.166-172
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• 2014

Image classification is an important problem in computer vision. However, it is a very challenging problem due to the variability, ambiguity and scale change that exists in images. In this paper, we propose a method of a hypergraph based modeling can consider the higher-order relationships of semantic attributes of a scene image and apply it to a scene image classification. In order to generate the hypergraph optimized for specific scene category, we propose a novel search method based on a probabilistic subspace method and also propose a method to aggregate the expression values of the member semantic attributes that belongs to the searched subsets based on a linear transformation method via likelihood based estimation. To verify the superiority of the proposed method, we showed that the discrimination power of the feature vector generated by the proposed method is better than existing methods through experiments. And also, in a scene classification experiment, the proposed method shows a competitive classification performance compared with the conventional methods.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.169-169
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• 2017

스마트 돈사 내의 열환경 분석에 필수적으로 고려되어야 인자는 가축의 복사 에너지 변화로 볼 수 있다. 열환경 제어의 대상이기도 하지만 회귀적으로 열환경 변화의 인자이기도 하다. 이러한 가축의 복사 에너지 분석을 위하여 시설 내에 용이하게 배포가 가능한 열화상 계측 시스템을 개발하였다. 초소형 마이크로 열화상 계측 시스템에 부가적으로 IOT(Internet of Thing) 기반 기술을 이용한 모듈화 개발을 병행하였다. 열화상 계측 센서로 LWIR(Longwave infrared)영역에 해당하는 $8{\mu}m{\sim}4{\mu}m$의 영역에서 $0.05^{\circ}C$의 분해능을 보이는 $Lepton^{TM}$ (500-0690-00, FLIR, Goleta, CA)모델을 사용하였다. SPI(Serial Peripheral Interface) 속도 2 Mhz로 마이크로프로세서(NanoPi NEO Air, FrendlyArm, CA, USA)와 고속 통신을 수행하여 9 Hz의 계측이 가능하다. 열화상 센서와 마이컴으로 구성되는 단위 계측 시스템의 통신 기능 확장을 위하여 다음과 같이 세 단계의 정보 전달 시나리오를 설계하였다. 1) 단독적으로 열화상을 계측 하고 내장된 메모리에 저장하는 형식 2) 인접한 사용자 인터페이스에서 1번 단독 모듈에 접속하여 열화상을 실시간으로 전송하여 화면에 도시하는 형식 3) 2번 사용자 도시모듈과 병행적으로 Local WI-FI 통신을 이용한 모바일 기기에 화면을 도시하는 형식. 이와 같은 계층적이며 모듈화된 계측 시스템을 구성하기 위해서 1번 모듈에 공개 소프트웨어인 Hostapd 2.5(http://w1.fi/hostapd)버전을 설치하였다. 외부 인터넷 환경이 없는 상황에 1번 모듈 단독으로 AP(Access Point) 기능을 제공하여 지근 거리에 있는 2번 모듈과 3번 모바일 기기의 접속을 관리할 수 있다. 2번 모듈의 경우 화면 다수의 1번 모듈에 접속을 교차적으로 수행하는 방식과 2번 모듈 자체가 AP가 되어 1번 모듈의 접속을 허용하는 형태로 구성되어 있다. 계측 시스템의 계측 매트릭스 구성에 따라 선택적으로 결정할 수 있다. 1번 2번 모듈 공통적으로 TCP/IP Listener와 Client 서비스를 병렬적으로 수행할 수 있도록 개발을 하였다. 3번 모바일 기기에서 사용자 인터페이스 구현을 위하여 범용 Android 기반 GUI 프로그램과 Socket 통신을 연동시켰다. 1개의 열화상 Frame의 전송량은 9,600 Byte ($=80{\times}60{\times}2Byte$) 로 WI-FI 통신 전송 시 2회 ~ 6회 정도 내외로 가변적인 통신 수행 횟수를 나타내었다. 센서 계측 시스템과 정보 전송 시스템을 병렬적으로 구성한 모듈화 된 계측시스템의 전 요소에서 센서에서 제공하는 최대 계측 주기인 9 Hz 구현이 일반적으로 가능하였다. 이를 이용한 추후 연구를 통해 가축 객체의 열복사 정보와 돈사 내 열환경 간의 역학성을 연구할 것이다.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.6
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• pp.747-752
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• 2006

In this paper, the adaptive fuzzy sliding mode controller with two systems is designed. The existing sliding mode controller used to $approximation{\^{u}}(t)$ with discrete sgn function and sat function for keeping the state trajectories on the sliding surface[1]. The proposed controller decrease the disturbance for uncertain control gain and This paper is concerned with an Adaptive Fuzzy Sliding Mode Control(AFSMC) that the fuzzy systems ate used to approximate the unknown functions of nonlinear system. In the adaptive fuzzy system, we adopt the adaptive law to approximate the dynamics of the nonlinear plant and to adjust the parameters of AFSMC. The stability of the suggested control system is proved via Lyapunov stability theorem, and convergence and robustness properties ate demonstrated. Futhermore, fuzzy tuning improve tracking abilities by changing some sliding conditions. In the traditional sliding mode control, ${\eta}$ is a positive constant. The increase of ${\eta}$ has led to a significant decrease in the rise time. However, this has resulted in higher overshoot. Therefore the proposed ${\eta}$ tuning AFSMC improve the performances, so that the controller can track the trajectories faster and more exactly than ordinary controller. The simulation results demonstrate that the performance is improved and the system also exhibits stability.

• Journal of KIISE
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• v.43 no.12
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• pp.1365-1375
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• 2016

One of the most important capabilities for autonomous service robots working in living environments is to recognize and understand the correct context in dynamically changing environment. To generate high-level context knowledge for decision-making from multiple sensory data streams, many technical problems such as multi-modal sensory data fusion, uncertainty handling, symbolic knowledge grounding, time dependency, dynamics, and time-constrained spatio-temporal reasoning should be solved. Considering these problems, this paper proposes an effective dynamic context management and spatio-temporal reasoning method for intelligent service robots. In order to guarantee efficient context management and reasoning, our algorithm was designed to generate low-level context knowledge reactively for every input sensory or perception data, while postponing high-level context knowledge generation until it was demanded by the decision-making module. When high-level context knowledge is demanded, it is derived through backward spatio-temporal reasoning. In experiments with Turtlebot using Kinect visual sensor, the dynamic context management and spatio-temporal reasoning system based on the proposed method showed high performance.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2001.11a
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• pp.45-45
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• 2001

종이 표변에 전분 사이징을 하는 목적은 종이가 액체에 대하여 침투저항성을 부여하 여 종이의 인쇄적성을 향상시키며 아울랴 종이의 표면적성과 종이강도 등의 물리적 특 성을 향상시키기 위해서 사용된다. 표면 사이징은 기본적으로 종이 표면에 전분을 이용 한 필름을 형성하여 종이 표면의 공극크기를 줄여 인쇄잉크 등과 같은 액체의 침투속 도를 늦여준다. 현재 국내에서 널리 사용되는 표면 사이징용 전분으로는 산화전분과 자 가변성용 일반전분이 있다. 자가변성용 전분은 효소나 APS로 전분의 chain 길이를 적 당한 점도로 잘라주는 것으로 전분 호액의 노화가 쉽게 일어나는 경향이 있다. 산화전 분은 전분회사에서 산화제를 이용하여 전분의 점도를 사용자의 요구에 따라 조절한 것 으로 water holdout이 개선되고 자가변성용 전분보다는 노화 안정성이 개선되지만 종 이 내부로의 칩투가 많이 일어나 전분 필름 강도가 약해지며 표면 강도 향상 효과가 적고 종이의 광학적 특성을 저하시키는 단점을 지니고 있다. 또한 약 10 ~ 20% 정도 사 용되는 파지의 재활용시 펄프 섬유에 흡착되지 않는 전분으로 인해 백수 내의 COD 및 B BOD를 증가시키는 원인이 된다.따라서 본 연구에서는 펄프 섬유와 친화력이 높아 지료 내첨용 지력증강제로 널리 사용되고 있는 양성 전분의 양이온 치환도 및 점도를 사이즈 프레스에 적합하게 조절 하여 백상지 제조업체의 라언에 적용하였다. 결과분석 항목으로는 파지 재활용에 따른 백수내 COD, 칼숨 이온함량 등의 백수 시스템의 변화와 종이의 물리적, 광학적 특성 및 ink jet 용지의 인쇄적성 등을 측정하여 산화전분과 비교하였다. 그 결과 약 20%의 C COD 감소 효과와 10%정도의 OPR 향상 효과를 얻을 수 있었다. 종이 물성의 경우 인 장강도와 뺏뺏이(stiffness) 및 지분 등을 측정한 결과 산화전분 보다 향상되었다. 특히 지분의 경우, 참여한 회사의 지분관련 complain이 약 80% 정도 감소하는 결과를 나타 내었다. 또한 백상지의 경우 ink jet 프린터에 많이 사용됨으로 ink jet 프린터의 인쇄 적성을 image analyzer로 측정한 결과 산화전분 보다 향상된 결과를 나타내었다.

• Journal of the Korean Professional Engineers Association
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• v.19 no.2
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• pp.10-20
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• 1986

This paper describes a countermeasure of electric utilities and customer equipment in order to minimize an effect of sensitive electrical and electronic equipment on the voltage disturbances. After being studied, some schemes to solve were discovered. Firstly, in the electric utilities, the reduction of frequency and influence of voltage drop's time are not easy to realize because of the standpoint of effect and economy. Secondly, in the customer equipment, there are some equipment to minimize the voltage disturbances, Such as an UPSs, a noise suppressors and a power conditioners. One of them should be established on the computer control and automated systems, the electromagnetic switch of delay-release type should be adopted on the electromagnetic switch, the controlling circuit should be adopted on the variable speed motors which is being considered a countermeasure for a momentary under-voltage drops, the luminaire adhering a instantaneous restrike device should be adopted on the HID lamp. And also, the scheme of extending a setting time of relay on the undervoltage relay and the forming method of sequence which is automatic reclosing at this time of instantaneous suspension of an electric supply have been studied.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.5
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• pp.533-540
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• 2013

Prime movers in engine rooms inherently are much affected by the adjustment of their governors for the steady state and transient properties, consequently requiring that marine engineers shall be well familiar with the way to manage governor dials for normal operation. The hydro-mechanical governors basically have different control characteristics and adjustment parameters of stability from digital governors. The former include compensation mechanism using dash pot while the control algorithm of the latter is usually based on the PID action. This study is for configuring a simulation module to let trainees practice how to adjust dials for stability on hydraulic governors in the view that the practice by real governors and engines is time consuming and high cost for operation. The governor module includes the adjusting points such as speed set, speed droop, needle valve and compensation pointer with engine module of $2^{nd}$ order coupled. The results of simulation showed satisfactory responses as a training tool for the adjustment of control parameters.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.3
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• pp.179-184
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• 2019

In many countries, such as developing countries where electricity is scarce, small wind turbines in the form of Off Grid are an effective solution to solve power supply problems. In some countries, the expansion of power systems and the decline of electricity-intensive areas have led to the use of small wind power in urban road lighting, mobile communications base stations, aquaculture and seawater desalination. With this change, the size of the small wind power industry is expected to have greater potential than large-scale wind power. In the case of small wind power generators, the generator is controlled at a variable speed, and the voltage and current generated by the generator have many harmonic components. To solve this problem, the AC to DC converter to be studied in this paper is a three-phase step-up type converter with a single switch. The inductor current is controlled in discontinuous mode, and has a characteristic of having a unit power factor by eliminating the harmonic of the input current. The proposed converter is composed of LCL filter and three phase rectification boost converter at the input stage and a single phase full bridge for grid connection. It is a control system with energy storage system(ESS) that the system stabilization can be pursued against the electric power.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.2
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• pp.149-162
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• 2005

This paper suggest a way to detect a specific wanted figure in public places such as subway stations and banks by comparing color face images extracted from the real time CCTV with the face images of designated specific figures. Assuming that the characteristic of the surveillance camera allows the face information in screens to change arbitrarily and to contain information on numerous faces, the accurate detection of the face area was focused. To solve this problem, the normalization work using subsampling with $20{\times}20$ pixels on arbitrary face images, which is based on the Perceptron Neural Network model suggested by R. Rosenblatt, created the effect of recogning the whole face. The optimal linear filter and the histogram shaper technique were employed to minimize the outside interference such as lightings and light. The addition operation of the egg-shaped masks was added to the pre-treatment process to minimize unnecessary work. The images finished with the pre-treatment process were divided into three reception fields and the information on the specific location of eyes, nose, and mouths was determined through the neural network. Furthermore, the precision of results was improved by constructing the three single-set network system with different initial values in a row.