• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.269-270
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• 2011

본 논문은 계통연계형 태양광 발전 시스템에서 유효, 무효전력 주입 시 성능개선을 위한 슬라이딩 모드가 적용된 직접전력제어 기법을 제안한다. 제안하는 제어 기법은 공간벡터변조 방식이 적용된 직접전력제어에서 적합한 비례-적분제어기의 모델링을 함으로 적절한 제어기의 이득을 설정한다. 직접전력 제어의 우수한 응답특성을 유지하기 위하여 가변구조제어의 한종류인 슬라이딩 모드제어를 적용한다. 제안하는 알고리즘의 검증을 위하여 시뮬레이션을 수행하여 제안하는 제어기법의 타당성을 확인 한다.

• Journal of Korea Multimedia Society
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• v.4 no.3
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• pp.222-229
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• 2001

Many techniques have been proposed for digital image enlargement, which use spatially neighbored pixels information in a still image. In this paper, we propose the digital image interpolation method that improves edge characteristics by selectively transposing the sub-windows of pseudomedian filter, which results in relatively better performance than others. We have simulated the proposed algorithm using Visual C++ and verified performance of the algorithm by PSNR(Peak signal Noise Ratio) and edge characteristics. Finally, we have designed the adaptive pseudomedian by using synopsys VHDL(Very high speed integrated circuit Hardware Description Language).

• Proceedings of the KIEE Conference
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• 2004.11d
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• pp.33-36
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• 2004

단상 및 3상 부하를 동시에 공급할 수 있는 3강 4선식 배전시스템은 일반 수용가 및 상업용, 공장 등의 시설에 널리 적용되고 있다. 한대의 변압기로 전력을 공급할 수 있으므로 작은 공간과 시스템 구성의 간편함이 장점이지만, 부하 운전패턴의 다양화와 컴퓨터 및 가변속 드라이브와 같은 비선형부하의 사용 증가시 전압불평형에 의한 문제점 발생은 큰 문제가 되고 있다. 외국의 경우 전압불평형에 의한 영향을 줄이기 위해 전압별 또는 부하의 종류에 따라 전압불평형율에 대한 규정을 제시하고 있으나, 국내에서는 전기철도와 같은 대형 부하에서만 전압불평형율의 기준만 정립되어 있고, 선형 및 비선형부하에 대해서는 규정이 제시되어 있지 않아 점차 증가하는 다양한 부하의 종류에 효율적으로 대처하기가 매우 어렵다. 따라서 본 연구에서는 국내외 전압불평형율에 대한 기준의 비교와 측정방법에 대한 내용을 제시 하고자 한다.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.88-90
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• 2008

본 논문은 이중여자 유도형(DFIG) 풍력발전 시스템에서 유효전력과 무효전력을 직접적으로 제어하기 위해 가변구조제어의 일종인 스위칭 이득기반의 선형궤환(LFSG)제어기법을 제시한다. 개조된 직접전력제어기법 (DPC)과 공간벡터변조방식(SVM)은 제안하는 제어기법을 실현하기 위해 이용된다. 개조된 직접전력제어원리를 이용해서 설계된 LFSG제어기법은 널리 사용되고 있는 자속기준제어기법(FOC)에 비해서 간단한 제어구조로 강인성과 빠른 응답특성을 보인다. 시뮬레이션결과는 제안하는 제어전략의 타당성과 강인성을 확인해준다.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.4
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• pp.504-510
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• 2009

Recently, personalized-adaptive services became the center of interest in the world. However the services about music are not widely diffused out. That is because the analyzing of music information is more difficult than analyzing of text information. In this paper, we propose a music recommendation system which provides personalized services. The system keeps a user's listening list and analyzes it to select pieces of music similar to the user's preference. For analysis, the system extracts properties from the sound wave of music and the time when the user listens to music. Based on the properties, a piece of music is mapped into a point in the property space and the time is converted into the weight of the point. At this time, if we select and analyze the group which is selected by user frequently, we can understand user's taste. However, it is not easy to predict how many groups are formed. To solve this problem, we apply the K-means clustering algorithm to the weighted points. We modified the K-means algorithm so that the number of clusters is dynamically changed. This manner limits a diameter so that we can apply this algorithm effectively when we know the range of data. By this algorithm we can find the center of each group and recommend the similar music with the group. We also consider the time when music is released. When recommending, the system selects pieces of music which is close to and released contemporarily with the user's preference. We perform experiments with one hundred pieces of music. The result shows that our proposed algorithm is effective.

• Archives of design research
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• v.13 no.3
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• pp.281-292
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• 2000

Today, the rapid economic growth and emerging new trends have been changed radically throughout the society and they especially have affected the changes of life-style and the diversity of residents'demands in housing life. This changes of life have brought the shift in family form from traditional type, thus new phase of nuclear family means that it makes on the whole, variable family forms such as single family, non-blood one, a generation one and so on. It therefore is time that we should not only explore current housing plans, but envisage concept of new living space to satisfy latent need of the occupants. But the forms, in spite of the diversity of user's needs and the change of life-style, of many houses as many apartment and tenement houses supplied so far have been clearly limted, and housing policy of the mass-supply causes monotonous space composition, over-occupation and non-changeability. Now, the collective houses have some limits owing to the commoness and assemblage, but they have failed to keep up with the variable and changeable life-style of residents. These problems, to put it concretely, lead to increasing needs for the number of rooms in proportion to family members, for the change of behavior using the space. We therefore need to propose the new living space. As the current plans for designing house are based on the average life-style of people, they can not cope with variable demands of the resident. For that reason, this paper will propose the manual space system as an alternative for it and the goal is to suggest new furniture system which we need to create the flexibility of living space.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.12 no.2
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• pp.209-218
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• 1994

This study aims to generate triangulated irregular network in a form of digital terrain model which is being increasingly used. In general, grid digital elevation model and triangulated irregular network are reasonable units for solving terrain problems. But, triangulated irregular network is an efficient alternative to grid digital elevation model because of their efficiency in storing data and their convenient data structure for accommodating irregularly spaced elevation data. Various methods represented for extracting triangulated irregular networks from grid digital elevation model, and then algorithm that get accurate results for triangulation with their data set was introduced. The new approach for triangulation in this study uses the Elevation and Changeable Distance criterion, and adding interpolation points and restricted constraint lines can generate triangulated irregular network which is more close to real surface. This made database efficient construction and could be used for many applications of geo-spatial information system.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.4
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• pp.318-324
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• 2017

We introduced a stereo camera on the aircraft to detect flight objects and to estimate the 3D position of them. The Saliency map algorithm based on PCT was proposed to detect a small object between clouds, and then we processed a stereo matching algorithm to find out the disparity between the left and right camera. In order to extract accurate disparity, cost aggregation region was used as a variable region to adapt to detection object. In this paper, we use the detection result as the cost aggregation region. In order to extract more precise disparity, sub-pixel interpolation is used to extract float type-disparity at sub-pixel level. We also proposed a method to estimate the spatial position of an object by using camera parameters. It is expected that it can be applied to image - based object detection and collision avoidance system of autonomous aircraft in the future.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.81-86
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• 2014

A smart phone subscriber needs wide bandwidth services for more fast data communication on the internet. The conventional MIMO system is now developing to resolve these problems with limited device space for antenna and frequency band environment reserved. One of way to make it practically is to add the number of antennas theoretically. But it is difficult to increase the antenna element as a limited space on the system. Therefore an active beam forming scheme is known as a way of constructing a Compact MIMO system for that. In this paper, the fast switching control block was suggested to adjust a reactance of the antenna element and verified experimentally the effects by switching signal on an orthogonal beam forming through a spatial domain.

• Korean Institute of Interior Design Journal
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• v.15 no.5 s.58
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• pp.120-129
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• 2006

Apartments have become the most popular type of residential building in Korea since the 1960s. The dwelling space should be designed to accomodate various life styles or changing needs of family members. This research is conducted to analyze flexible interior space types of apartments and to improve the architectural planning and design of apartments that can satisfy various needs of residents. In this study, apartments of 10 - 90 pyeongs built in the region of Seoul, between 1998 and 2007, are investigated in terms of the unit plan, the number of open sides, and a distribution of flexible apartment types for each year, Apartments with flexible space are classified into 10 different types, including a flexible type between bedrooms, a flexible type between a bedroom and the livingroom, and a flexible type between the dinning room and the livingroom. According to the composition of unit plans, apartments are also differentiated as a single-corridor type, a double-corridor type, a stairway type, a hall type, and a combination type. According to these classifications, the characteristics of desirable unit plans were analyzed. The results of the analysis showed that, as the unit size of apartments get bigger, the ratio of width/depth of the front side unit plan is increased. This result reflects a trend of high-rise apartments which have an increased number of front-side bays and a shorter depth for better penetration of daylight. In addition, a hall type is found to have a wider front side and shorter depth. According to open sides, a flexible type of the livingroom and the dinning room/kitchen (L-D.K) is found to be most common for the front/back open space, and the livingroom is usually placed on the front/side open space. To meet the changing needs of residents, more research should be conducted on flexible dwelling space.