• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
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• pp.226-229
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• 2001

The combined transmission lines with the underground power cables are continuously expanded in power systems. So the fault of combined transmission line is increased every year as the complication of underground transmission line. In this paper. traveling wave theory and DWT wavelet transform are used for fast and accurate detection of fault location at the combined transmission line. Traveling wave travels to each bus like surge and repeats reflection and transmission till transient signal is completely disappeared. When fault is occurred on overhead and underground tine, the fault location detecting algorithm was performed with using continuous peak value time-delay of traveling wave reflected from A bus.

• Communications for Statistical Applications and Methods
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• 제25권3호
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• pp.263-274
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• 2018

One of the common issues in large dataset analyses is to detect and construct homogeneous groups of objects in those datasets. This is typically done by some form of clustering technique. In this study, we present a divisive hierarchical clustering method for two monothetic characteristics of histogram data. Unlike classical data points, a histogram has internal variation of itself as well as location information. However, to find the optimal bipartition, existing divisive monothetic clustering methods for histogram data consider only location information as a monothetic characteristic and they cannot distinguish histograms with the same location but different internal variations. Thus, a divisive clustering method considering both location and internal variation of histograms is proposed in this study. The method has an advantage in interpreting clustering outcomes by providing binary questions for each split. The proposed clustering method is verified through a simulation study and applied to a large U.S. house property value dataset.

• Journal of Information Processing Systems
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• 제17권2호
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• pp.352-368
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• 2021

Sign-in point of interest (POI) are extremely sparse in location-based social networks, hindering recommendation systems from capturing users' deep-level preferences. To solve this problem, we propose a content-aware POI recommendation algorithm based on a convolutional neural network. First, using convolutional neural networks to process comment text information, we model location POI and user latent factors. Subsequently, the objective function is constructed by fusing users' geographical information and obtaining the emotional category information. In addition, the objective function comprises matrix decomposition and maximisation of the probability objective function. Finally, we solve the objective function efficiently. The prediction rate and F1 value on the Instagram-NewYork dataset are 78.32% and 76.37%, respectively, and those on the Instagram-Chicago dataset are 85.16% and 83.29%, respectively. Comparative experiments show that the proposed method can obtain a higher precision rate than several other newer recommended methods.

• 한국정보통신학회논문지
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• 제17권6호
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• pp.1477-1486
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• 2013

본 논문에서는 ZigBee를 기반으로 하는 무선 통신기술을 이용한 위치인식 시스템을 구현하였다. 무선 통신 기술을 이용하여 보다 정밀한 위치정보를 산출하고 위치정보를 서비스하기 위하여 관련 H/W와 S/W를 개발하였다. 위치인식 시스템을 구현하기 위해 스마트 태그(위치단말기), 수신기, 중계기를 개발하였고, 스마트 태그에는 120~130KHz, 13~14MHz, 2.0~3.0GHz의 무선주파수용 태그를 내장하였으며, 수신기 및 중계기는 태그 인식용 무선신호를 송출하여 위치단말기의 액티브 RFID 태그를 인식하는 태그 모듈을 적용하였다. 공동현관 관제기는 스마트 태그를 공동현관 관제기에 가져가면 LAN을 통해 출입통제 서버로 태그 값을 전송하도록 시스템을 구현하였다.

• 대한전기학회논문지:전력기술부문A
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• 제55권3호
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• pp.116-122
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• 2006

The underground transmission lines is continuously expanded in power systems. Therefore the fault of underground transmission lines are increased every year because of the complication of systems. However the studies dealing with fault location in the case of the underground transmission lines are rarely reported except for few papers using traveling wave method and calculating underground cable impedance. This paper describes the algorithm using fuzzy system and travelling wave method in the underground transmission line. Fuzzy inference is used for fault discrimination. To organize fuzzy algorithm, it is important to select target data reflecting various underground transmission line transient states. These data are made of voltage and average of RMS value on zero sequence current within one cycle after fault occurrence. Travelling wave based on wavelet transform is used for fault location. In this paper, a variety of underground transmission line transient states are simulated by EMTP/ATPDraw and Matlab. The input which is used to fault location algorithm are Detail 1(D1) coefficients of differential current. D1 coefficients are obtained by wavelet transform. As a result of applying the fuzzy inference and travelling wave based on wavelet transform, fault discrimination is correctly distinguished within 1/2 cycle after fault occurrence and fault location is comparatively correct.

• 한국산학기술학회논문지
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• 제21권9호
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• pp.466-472
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• 2020

본 연구는 자유선택놀이 활동에서 유아의 또래관계 탐색을 위한 위치데이터의 활용 방안을 탐색하는 것을 목적으로 한다. 이를 위해 충남 소재 유아교육기관 1개 학급, 14명을 대상으로 웨어러블 디바이스를 활용하여 위치데이터를 수집했다. 수집한 위치데이터의 전처리를 위해 스무딩 기법을 적용하여 수집 과정에서 발생한 결측치를 복구하고 파이썬의 Matplotlib를 활용해 데이터를 시각화했다. 이후 수식을 활용하여 위치데이터에서 이동거리, 유아 간 거리, 유아의 상호작용 유형을 추출했다. 연구결과 시간의 흐름에 따른 1) 이동거리의 변화와 누적값 및 평균값, 2) 유아간 거리 변화와 평균 거리값 3) 상호작용 유형의 변화와 경향성을 도출할 수 있었다. 정보통신기술의 발달은 교육현장에 많은 변화를 야기하고 있으며 특히 최근 교육 현장에서는 학습자의 특성, 요구를 중심으로 다양한 교수-학습적 처방을 통한 맞춤형 교육에 대한 수요가 높아지고 있다. 이러한 연구결과는 교사가 모든 유아를 세밀하게 관찰하기 어려운 상황에서 유아들의 또래집단 형성 과정에 대한 정보를 제공할 수 있으며 이에 따른 교육 프로그램의 설계 및 운영에 유의미한 정보로 활용될 수 있다.

• 한국주거학회논문집
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• 제19권4호
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• pp.11-20
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• 2008

The purpose of this study is to gather baseline data on perceived housing values and satisfaction rates among consumers with the aim of using this information for future planning. Self-administered questionnaires were provided to 1000 university students from Gwangju and the Chonnam area from 2007 October 8th to 30th. The collected data was used to conduct comparative and descriptive statistical analysis: factor analysis, cluster analysis, t-test, $x^2-test$ and one-way ANOVA. The main findings are as follows: Firstly, in relation to perceived house values, students identified three factors as important: pursuit of convenience, disposition toward individuality-orientation and consciousness of others. The respondents regarded convenience as very important, especially in regard to one's safety, health and location of amenities. Secondly, cluster analysis based on perceived house value revealed passive and energetic types. Students in the energetic type exhibited a tendency to prefer convenience, independence, and consciousness of others. Finally in terms of housing satisfaction, the respondents identified four factors as important: house quality, neighborhood environment, local socio-psychological environment, and location. Housing satisfaction was higher among students who lived in large or new houses, shared the same house with their family, and had a room all to themselves. Accoding to these findings, university students important value safety, health and environmental-friendliness in a house and they find location important. Therefore, future houses should reflect these wants.

• Advances in Energy Research
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• 제5권2호
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• pp.147-177
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• 2017

This study aims to evaluate and prioritize ten different sites in Iran's Khorasan provinces for the construction of wind farm. After studying the geography of the sites, nine criteria; including wind power, topography, wind direction, population, distance from power grid, level of air pollution, land cost per square meter, rate of natural disasters, and distance from road network-are selected for the analysis. Prioritization is performed using data envelopment analysis (DEA). The developed DEA model is validated through value engineering based on the results of brainstorming sessions. The results show that the order of priority of ten assessed candidate sites for installing wind turbines is Khaf, Afriz, Ghadamgah, Fadashk, Sarakhs, Bojnoord, Nehbandan, Esfarayen, Davarzan, and Roudab. Additionally, the outcomes extracted from the value engineering method identify the city of Khaf as the best candidate site. Six different wind turbines (7.5 to 5,000 kW) are considered in this location to generate electricity. Regarding an approach to produce and store hydrogen from wind farm installed in the location, the AREVA M5000 wind turbine can produce approximately $337ton-H_2$ over a year. It is an enormous amount that can be used in transportation and other industries.

• 대한인간공학회지
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• 제35권5호
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• pp.449-464
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• 2016

Objective: The objective of this study is to identify essential requirements of the instrument cluster's features and layout for elderly drivers through interview and paper prototyping. Background: Recent updates implemented in passenger vehicles require more complex information to be processed by drivers. Concurrently, a large portion of the US population, the baby boomer generation has aged, causing their physical and cognitive abilities to deter. Thus it is crucial that new methods be implemented into vehicle design in order to accommodate for the deterioration of mental and physical abilities. Method: Forty elderly drivers and twenty young drivers participated in this study. The test included three sessions including: 1) location value assessment to identify the priority of areas within the instrument cluster; 2) component value assessment to capture rankings of the degree of importance and frequency of use for possible instrument cluster components; and 3) paper prototyping to collect self-designed cluster with selection of designs for each component and location of features from each participant. Results: Results revealed differences in the area priority of the instrument cluster as well as the shape and location of component features for age and gender groups. Conclusion: The study provided insights on instrument cluster layout guidelines by proving elderly driver's mental model and preferred cluster design configurations to improve driving safety. Application: LCD-based vehicle instrument cluster design, with an adaptable feature configuration for cluster components and layouts.

• 대한기계학회논문집
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• 제16권4호
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• pp.795-802
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• 1992

본 연구에서는 일정한 각도의 분사를 갖는 평씨일(plain seal)에 대하여 각 인자들이 누수성능에 미치는 영향을 수치적으로 조사하였다. 인자들로는 축방향 레 이놀즈수, 축회전속도, 분사의 유입속도, 간극비, 분사의 위치 및 유입각 등이 고려되 었다.