• Title/Summary/Keyword: Choi criteria

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Optimal trade-off filters for Noise Robustness, Peak Sharpness and Light Efficiency in the Nonoverlapping Background Noise (배경이 물체에 겹치지 않는 영상에서 잡음에 대한 안정성, 출력의 최대값 크기, 광효율을 고려한 최적 Trade-off 필터)

  • Seong, Yeong-Kyeong;Choi, Tae-Sun
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.37 no.4
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    • pp.56-64
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    • 2000
  • The design of filters for pattern recognition that have optimal trade-off for the criteria of noise robustness, peak sharpness and Homer efficiency, when input scene noise is spatially disjoint (nonoverlapping) with the target, are presented Three different criteria, ie, signal-to-noise ratio, peak-to-output energy ratio and light efficiency are used to design the filter. Computer simulation is made for the various types of noise and parameters to illustrate filter performance for optical pattern recognition. When we compare the new trade-off filter with the original optimal trade-off filter, the performance of trade-off filter for nonoverlapping background is better than that of trade-off filter for overlapping background.

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Visual Environmental Elements of Game Space by Play-Event in Adventure Games (어드벤처 게임에서 플레이이벤트별 게임공간의 시각적 환경요소)

  • Choi, GyuHyeok;Jin, Hyungwoo;Kim, Mijin
    • Journal of Korea Game Society
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    • v.20 no.1
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    • pp.47-56
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    • 2020
  • The purpose of this study is to analyze visual environmental elements of game space by play-event in adventure games. We extracted common six types of play-event through exploring ten representative adventure games and organized three types of space structure and four types of object as the criteria of analysis. Based on the criteria, we embodied the characteristics of visual environmental elements by performing direct playing and monitoring. As a result, we verified that the story intended and the gameplay induced by the play-event are closely related to visual environmental elements.

Criteria of Impact Resistance of Lightweight Wall by the Large Soft Body (건식 경량벽체의 연질 충격체에 의한 내충격성 판정기준에 관한 연구)

  • Kim, Ki Jun;Song, Jung Hyeon;Choi, Soo Kyung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.05a
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    • pp.102-103
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    • 2014
  • Due to the nature of the existing load, the criteria of assessing the intensity of the lightweight wall's impact resistance has been though of as obscure. The current study, therefore, focuses on the standardized assessment of the impact resistance to the force of the large soft body applying to the lightweight wall. The gypsum board wall showed a low level of the maximum residual displacement. It is, however, required to be careful about the selection of the finishing process since the high level of the maximum displacement is likely to cause harm to finishing materials. Unlike the gypsum board, the ALC block wall displayed a considerable rigidity while showing almost no maximum residual displacement. Even with the low level of the maximum displacement due to the stiffness, the ALC block wall is still likely to be affected by the vibration derived from any impact on the surface, which demands a need for additional study. The future experimental study, accordingly, will focus on the impact of the vibration on finishing materials, consequently leading to the accurate prediction of the possibility of potential damage to the lightweight wall caused by the large soft body.

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A basic study on the Eco-friendly elements evaluation of Hanok according to G-SEED -Focus on the Unjoru and Jinwondang- (녹색건축인증제(G-SEED)에 따른 한옥의 친환경 요소 평가에 관한 기초연구 -구례 운조루와 진원당을 중심으로-)

  • Choi, Hyung-Seok;Kim, Hark-Rae
    • Journal of the Korean Institute of Rural Architecture
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    • v.17 no.1
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    • pp.9-18
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    • 2015
  • The purpose of this study is to analyze the usage of eco-friendly elements in Korean traditional architecture to evaluate Hanok(Unjoru and Jinwondang) according to Green Building Certification Criteria(G-SEED). The results of this study were as follows; Unjoru and Jinwondang was not enough to obtain certification points. From Site usage and Traffic category, Jinwondang gets more points than Unjoru. It's because Jinwondang is located in downtown Seoul, so it gets more points of traffic and neighborhood facility. From Energy and Environmental Pollution category, Jinwondang gets more points of energy performance than Unjoru, too. It's because Jinwondang secured insulation performance of wall and windows using insulator and glass. From Resources category, Unjoru gets more points than Jinwondang. It shows that modern Hanok was limited using natural resources. From Ecological Environments category, Jinwondang is located urban area, it's difficult to secure the open space, so Unjoru gets more points than Jinwondang. If Modern Honok installs a system that can getting point and secure insulation performance, it will be certificated according to G-SEED.

Seismic Capacity Test of Nuclear Piping System using Multi-platform Shake Table (다지점 진동대를 이용한 원자력발전소 배관계통의 내진성능실험)

  • Cheung, Jin-Hwan;Gae, Man-Soo;Seo, Young-Deuk;Choi, Hyoung-Suk;Kim, Min-Kyu
    • Journal of the Earthquake Engineering Society of Korea
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    • v.17 no.1
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    • pp.21-31
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    • 2013
  • In this study, dynamic characteristics and seismic capacity of the nuclear power plant piping system are evaluated by model test results using multi-platform shake table. The model is 21.2 m long and consists of straight pipes, elbows, and reducers. The stainless steel pipe diameters are 60.3 mm (2 in.) and 88.9 mm (3 in.) and the system was assembled in accordance with ASME code criteria. The dynamic characteristics such as natural frequency, damping and acceleration responses of the piping system were estimated using the measured acceleration, displacement and strain data. The natural frequencies of the specimen were not changed significantly before and after the testing and the failure and leakage of the piping system was not observed until the final excitation. The damping ratio was estimated in the range of 3.13 ~ 4.98 % and it is found that the allowable stress(345 MPa) according to ASME criteria is 2.5 times larger than the measured maximum stress (138 MPa) of the piping system even under the maximum excitation level of this test.

Vibration Characteristics of a Dummy Fuel Rod Supported by Spacer Grids (지지격자로 지지된 모의 연료봉의 진동특성)

  • Choi, Myoung-Hwan;Kang, Heung-Seok;Yoon, Kyung-Ho;Kim, Hyung-Kyu;Song, Kee-Nam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.3
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    • pp.424-431
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    • 2003
  • The spacer grid is one of the main structural components in the fuel assembly, which supports the fuel rods and maintains coolable geometry from an external load. A vibration test and a finite element analysis using ABAQUS on a dummy fuel rod continuously supported by Optimized H type(OHT) and New Doublet (ND) spacer grids arc performed to obtain the vibration characteristics such as natural frequencies and mode shapes an(1 to verify a finite element model. The results from the test and the finite element analysis are compared by modal assurance criteria (MAC) values. It is resulted that MACs for the first, the third and the fifth mode shapes are relatively good as compared with those of the second an(1 fourth ones. The natural frequency differences between two methods as well as the mode comparison results for the rod with OHT spacer grid are better than those with ND spacer grid. It is judged that the FE model for the ND spacer grid spring should be modified to consider the long contact length which actually happen when the spring supports the rod.

Development of a Material Mixing Method for Topology Optimization of PCB Substrate (PCB판의 위상 최적화를 위한 재료혼합법의 개발)

  • Han, Seog-Young;Kim, Min-Sue;Hwang, Joon-Sung;Choi, Sang-Hyuk;Park, Jae-Yong;Lee, Byung-Ju
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.1
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    • pp.47-52
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    • 2007
  • A material mixing method to obtain an optimal topology for a structure in a thermal environment was suggested. This method is based on Evolutionary Structural Optimization(ESO). The proposed material mixing method extends the ESO method to a mixing several materials for a structure in the multicriteria optimization of thermal flux and thermal stress. To do this, the multiobjective optimization technique was implemented. The overall efficiency of material usage was measured in terms of the combination of thermal stress levels and heat flux densities by using a combination strategy with weighting factors. Also, a smoothing scheme was implemented to suppress the checkerboard pattern in the procedure of topology optimization. It is concluded that ESO method with a smoothing scheme is effectively applied to topology optimization. Optimal topologies having multiple thermal criteria for a printed circuit board(PCB) substrate were presented to illustrate validity of the suggested material mixing method. It was found that the suggested method works very well for the multicriteria topology optimization.

FBG Sensor Probes with Silver Epoxy for Tracing the Maximum Strain of Structures

  • Im, Jooeun;Kim, Mihyun;Choi, Ki-Sun;Hwang, Tae-Kyung;Kwon, Il-Bum
    • Journal of the Korean Society for Nondestructive Testing
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    • v.33 no.5
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    • pp.459-464
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    • 2013
  • Structures can be evaluated their health status by allowable loading criteria. These criteria can be determined by the maximum strain. Therefore, in order to detect this maximum strain of structures, fiber optic Bragg grating(FBG) sensor probes are newly designed and fabricated to perform the memorizing detection even if the sensor system is on-and-off. The probe is constructed with an FBG optical fiber embedded in silver epoxy. When the load is applied and removed on the structure, the residual strain remains in the silver epoxy to memorize the maximum strain effect. In this study, a commercial Al-foil bonded FBG sensor probe was tested to investigate the detection feasibility at first. FBG sensor probes with silver epoxy were fabricated as three different sizes. The detection feasibility of maximum strain was studied by doing the tensile tests of CFRP specimens bonded with these FBG sensor probes. It was investigated the sensitivity coefficient defined as the maximum strain divided by the residual strain. The highest sensitivity was 0.078 of the thin probe having the thickness of 2 mm.

A survey on the perception of China private antidesertification afforestation support project and evaluation

  • Ji, Seung-Yong;Lee, Sang-Hyuk;Lee, Oh-Kyu;Choi, Jaeyong
    • Korean Journal of Agricultural Science
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    • v.43 no.2
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    • pp.288-297
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    • 2016
  • This study is to evaluate the 'Private antidesertification afforestation support project' in the Kubuqi Desert through a survey of local residents and interviews with relevant personnel. Based on this survey, gender, age, and occupational differences in perception of the project were analyzed. In addition, the project was evaluated based on the OECD/DAC criteria using survey results and in-depth interviews with the relevant personnel. The survey analysis results show that the participants answered most of the questions positively, claiming that they were receiving social, economic, and environmental benefits through the project. However, most of the participants answered negatively to questions regarding the understanding of the project and relevant information. Gender differences in perception of the project were not found, whereas, age and occupational differences in perception were found. Older age groups showed higher levels of perception. Participants in the agro-livestock industry and office workers showed higher levels of perception compared to middle/high school students, the unemployed and college students. Teenagers, in particular, showed the lowest level of perception of the project, and thus, promotional activities targeting teenagers should be conducted in the future. Results of this evaluation of the project based on the OECD/DAC's five criteria (relevance, effectiveness, efficiency, impact, and sustainability) showed that the project operated effectively for the most part.

Lifetime Assessment Criteria and Failure Analysis for the Clutch Coil in an Automotive Air Conditioner (자동차용 에어컨 클러치 코일의 수명평가 기준과 고장해석)

  • Choi, Man-Yeop;Wei, Shin-Hwan;Kim, Jung-Sik;Jeong, Hai-Sung
    • Journal of Applied Reliability
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    • v.11 no.2
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    • pp.111-126
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    • 2011
  • The clutch coil mounted on the automotive air conditioner is an important part which actuates the clutch to connect or disconnect the pulley and the compressor according to the climate control condition in an automobile. Here, it is generally required that the clutch coil should ensure the long term durability requirement, such as a warranty for the 10 years of field operation or 160,000 km driving, especially in a brand new item, and so forth. However, some difficulties have arisen in restoring its credibility, since domestic specifications for the part have not been yet unified. In order to ensure the reliability, test methods and assessment criteria should be standardized. Moreover, assessed lifetime under specific conditions and potential failure analysis would be important. In this study, lifetime test specifications for the clutch coil have been reviewed and methodological suggestions are provided to ensure reliability, utilizing a quality function deployment through the potential failure mode effect analysis.