• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.87-91
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• 2004

High aged society is rapidly progressing in Japan. The rate of aged person more than 65 years old in the population are estimated 25 % in 2017 and rate of younger population will be decreased at same time. As a result, it is estimated that the human resources that is looking after or supporting for the aged person will be drained in Japan. In the other hand, the society has to provide high quality of life in order to be improved living environment for aged person. To decrease the share of nursing and caring for the aged person, it is required that new supporting systems for aged person have to build up as soon as possible. But it is required that various kind of measurement for posture and movement in activities with a simple and single detector for the aged person. The measurement instrument has to be lightweight and simple structure. The results give us a simple measurement method are classified that the posture of sitting down, lying down in stationary statuses and walking, running and going to up and down on the stairs in moving statuses. The detected data will plane to transmit to wireless mobile system to the host computer.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1865-1868
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• 2003

This paper provides a new method for hybrid machining, particularly suited to micro fabrication applications such as micro point, micro line, micro structure, micro partition and so on. Developed micro fabrication process by electrical discharge machining (EDM) and electrical discharge deposition (EDD) with metal powder (Ti, Fe) has been studied to build TiC or FeC structure. Titanium powder or iron powder is supplied from working fluid (kerosene or de-ionized water with powder) and adheres on a workpiece by the heat and electric power caused by the electrical discharge. The use of a tool electrode is expected to keep powder concentration high in the gap between a workpiece and a tool electrode and to accrete powder material on the workpiece. The deposition is tried under various electrical conditions (workpiece. tool electrode, working fluid, discharge current, voltage and powder etc.). On the other hand. using electrical discharge machining (EDM) with the same tool electrode, it can be used as a removal process (cutting) by electro erosion at the same time. Therefore. this new method can do a hybrid machining to build up and down a structure with the workpiece.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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• pp.189-192
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• 2012

Underground structure construction in the downtown is very difficult despite the development of construction technology. We have been a lot of research in order to solve the problem, it was a remarkable achievement. But there are still many difficulties. This study is to analyze the construction technology to demolish the existing underground structures and to build new building applied topdown method at the same time. This technology was effective to suppress interference between the exsisting structure and new building. Therefore, this technology is expected to be able to be used in similar cases in the future.

• 제어로봇시스템학회논문지
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• 제4권4호
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• pp.525-533
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• 1998

A conventional contact type brake system which uses a hydraulic system has mny Problems such as time delay response due to pressure build-up, brake pad wear due to contact movement, bulky size, and low braking performance in high speed region. As vehicle speed increases, a more powerful brake system is required to ensure vehicle safety and reliability. In this work, a contactless brake system of an eddy current type is proposed to overcome problems. Optimal torque control which minimizes a braking distance is investigated with a scaled-down model of an eddy current type brake. It is possible to realize optimal torque control when a maximum friction coefficient (or desired slip ratio) corresponding to road condition is maintained. Braking force analysis for a scaled-down model is done theoretically and experimentally compensated. To accomplish optimal torque control of an eddy current type brake system, a sliding mode control technique which is, one of the robust nonlinear control technique is developed. Robustness of the sliding mode controller is verified by investigating the braking performance when friction coefficient is varied. Simulation and experimental results will be presented to show that it has superior performance compared to the conventional method.

• 대한의용생체공학회:의공학회지
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• 제44권3호
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• pp.167-175
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• 2023

Chest PA is the basic examination of radiographic imaging. Moreover, Chest PA's demands are constantly increasing because of the Increase in respiratory diseases. However, it is not meeting the demand due to problems such as a shortage of radiological technologist, sexual shame caused by patient contact, and the spread of infectious diseases. There have been many cases of using artificial intelligence to solve this problem. Therefore, the purpose of this research is to build an artificial intelligence dataset of Chest PA and to find a posture evaluation method. To construct the posture dataset, the posture image is acquired during actual and simulated examination and classified correct and incorrect posture of the patient. And to evaluate the artificial intelligence posture method, a posture estimation algorithm is used to preprocess the dataset and an artificial intelligence classification algorithm is applied. As a result, Chest PA posture dataset is validated with in over 95% accuracy in all artificial intelligence classification and the accuracy is improved through the Top-Down posture estimation algorithm AlphaPose and the classification InceptionV3 algorithm. Based on this, it will be possible to build a non-face-to-face automatic Chest PA examination system using artificial intelligence.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권7호
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• pp.3150-3171
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• 2018

In this paper, a heuristic method that leverages packet traces captured at the entire boarder of an ISP to distinguish and estimate the overall packet loss within an ISP's management domain (Intra_Path_Loss) and that in the outside Internet (Inter_Path_Loss) is proposed. Our method is inspired by that packet losses happened at different locations will cause different TCP sequence number patterns at the border of an ISP. Thereby, we leverage these TCP sequence number patterns to build a series of heuristic rules to estimate Intra_Path_Loss and Inter_Path_Loss, respectively. We do this work with an eye towards showing that the overall packet losses defined and estimated in this paper can provide the operators with some valuable information to help them precisely grasp the overall performance of network paths and narrow down the range of network anomalies. The proposed method is rigorously validated with simulations, and finally the results from a regional academic network JSERNET verify its effectiveness and practicability.

• 한국정보과학회논문지:데이타베이스
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• 제29권5호
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• pp.367-380
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• 2002

최근 공간 데이타 분석, 영상 분석 등과 같은 대용량 데이타를 관리하는 다양한 응용 업무들이 증가함에 따라, 대용량의 데이타베이스를 위한 클러스터링 기법이 많이 연구되고 있다. 그 중에서도 계층 클러스터링 기법은 데이타베이스의 계층 분할을 표현하는 계층 트리를 생성하고 이를 이용하여 효율적인 클러스터링을 수행하는 방법으로서, 지금까지는 주로 트리를 하위 계층으로부터 상위 계층으로 생성해 가는 상향식(bottom-up) 계층 클러스터링 기법들이 연구되었다. 이러한 상향식 클러스터링 방법은 트리를 생성하기 위하여 전체 데이타베이스를 한 번 이상 액세스하여야 할 뿐만 아니라, 하위 계층에서부터 검색을 시작하기 때문에 트리의 많은 부분을 검색하여야 하는 문제점이 있다. 본 논문에서는 대부분의 데이타베이스 응용에서 이미 유지하고 있는 다차원 색인을 이용하여 클러스터링을 수행하는 새로운 하향식(top-down) 계층 클러스터링 기법을 제안한다. 일반적으로 다차원 색인에서는 가까운 객체들이 동일한 (혹은 인접한) 페이지에 저장될 가능성이 큰 클러스터링 성질을 가진다. 이러한 다차원 색인의 클러스터링 성질을 사용하면 각 객체들간의 거리를 일일이 계산하지 않고도 이웃한 객체들을 식별할 수 있다. 우선 객체들의 밀도에 기반하여 클러스터를 정형적으로 정의한다. 이를 위하여, 객체를 포함하는 영역의 밀도를 이용한 영역 대조 분할(region contrast partition) 개념을 사용한다. 또, 클러스터링 알고리즘에서의 빠른 검색을 위하여 분기 한정(branch-and-bound) 알고리즘을 사용하며, 여기서의 한계값(bound)을 제안하고 이의 정확성을 이론적으로 증명한다. 실험 결과, 제안한 방법은 상향식 계층 클러스터링 방법인 BIRCH와 비교하여, 정확성 측면에서 우수하거나 유사한 것으로 나타났으며, 데이타 페이지 액세스 횟수를 데이타베이스 크기에 따라 최고 26～187배까지 감소시킨 것으로 나타났다. 이 같은 결과로 볼 때, 제안한 방법은 대용량 데이타베이스에서의 클러스터링 성능을 크게 향상시키는 기법으로서, 일반 데이타베이스 응용에 실용적으로 적용 가능하다고 판단된다.

• 한국정보과학회논문지:소프트웨어및응용
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• 제37권3호
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• pp.214-221
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• 2010

검색 결과 내 군집화(search-result clustering)는 검색 엔진으로부터 검색된 결과 내에서 비슷한 문서를 자동으로 군집화하는 기법이다. 본 논문에서는 논문 검색 서비스에 전문화된 새로운 결과 내 군집화 기법을 제안한다. 제안하는 시스템은 '범주체계생성기(Category Hierarchy Generation System)'와 '논문군집기(Paper Clustering System)'로 구성되어있다. '범주체계생생기'는 KOSEF의 연구 범주 체계를 이용하여 분야 시소러스라 불리는 범주 체계를 생성하고, K-means 알고리즘을 이용한 단어 군집화 알고리즘을 사용하여 분야 시소러스의 키워드 집합을 확장한다. '논문군집기'는 top-down 방식과 bottom-up 방식을 이용하여 각 논문의 범주를 결정한다. 제안하는 시스템은 논문 검색 서비스와 같은 전문 분야에 대한 검색 서비스에 유용하게 사용될 수 있을 것이다.

• 한국컴퓨터그래픽스학회논문지
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• 제25권3호
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• pp.31-41
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• 2019

포그 스크린은 미세한 물방울들로 구성된 스크린으로 관찰자는 포그 스크린을 투과한 영상을 관찰하게 된다. 일반 스크린과는 달리 관찰자는 무대 위에서 연기자가 포그 스크린에 표시된 이미지를 뚫고 들어가는 모습을 볼 수 있다. 본 논문에서는 상부에서 생성된 포그 입자 집단이 중력에 의하여 아래로 떨어질 때 평평한 수직 스크린을 이루도록 하는 하향식 포그 스크린 생성 장치 구현 방법을 기술한다. 본 기법은 수조안에 배치된 초음파 진동자에 의해 수조 표면에서 포그 입자가 발생되는 원리를 이용한다. 생성된 포그 집단이 하나의 평면을 유지할 수 있도록 포그가 나오는 통로 출구 양옆에 가이드 바람을 형성하는 기법과 포그 스크린 생성 장치의 설계와 제작 방법을 기술한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1405-1405
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• 2011

Sudden earthquake is changing national energy stratagem for future energy resource. In case Germany, current nuke power station will be shut down with several decades. Newly constructed build in Japan must have photovoltaic system as a obligations.. As a long-term sustainable energy one, PV should give confidence to customers up to more than 20 years. Today, IEC 61215 and IEC 61646 standards are representative one for ensuring performance and safety of PV module. But it is still needed to develop more realistic test method. For example, if we think about extreme condition like desert and North Pole, the temperature condition describe in test standards can have little effect on life time expectation of PV module. Installation speed of PV system is very high, but establishing test standards are very complex and not easy. So in this paper, I tried to open the long-term test method for PV module to ensure 25 year's old life time. It is just starting point of PV related long-term test methods. The specific and technical explanation will be shown in the following paper in detail.