멀티 콘센트용 변류기 및 과전류 검출 회로 설계

김용재,김민석,박규상,김재홍,Kim, Yong-Jae,Kim, Min-Seok,Park, Gyu-Sang,Kim, Jae-Hong 한국전자통신학회 2015 한국전자통신학회 논문지 Vol.10 No.8

멀티 콘센트의 과전류로 인한 과열을 방지하기 위한 보호방식으로는 주로 금속바이메탈 방식, 스위칭회로 방식, 마이크로컨트롤러(MCU)를 이용한 과전류 정밀제어 방식 등이 사용되어 오고 있다. 하지만 이러한 방식들은 보호회로가 과전류가 흐르는 전선에 병렬접속 함으로써 2차 화재의 위험이 있을 수 있으며 입력전압의 비선형 왜곡에 취약한 단점을 가지고 있다. 또한 기존의 방식들은 제품의 단가가 비교적 크게 올라가므로 충분한 시장성을 확보하기가 쉽지 않다. 본 논문에서는 이러한 문제를 해결하고자 과전류가 흐르는 전선에 비접촉식 관통형 변류기를 설계하고 변류기의 2차 유도전류를 이용하여 과전류를 감지하여 사용자가 과전류 상황을 인지할 수 있도록 LED 및 부저 회로를 통하여 시각 및 청각적 신호를 전달하는 기능을 구현한다. 실험 결과들로부터 제안된 회로는 매우 경제적이고 간단하면서도 안정적으로 동작함을 확인 할 수 있다. For the over-heat protection purpose in power strip devices, over-current detection/protection circuits, such as bimetal, switching circuit, and microprocessor-based relay circuit, have been widely setup in high-end products. Most of these circuits are connected to the power line in parallel and, thus, they are sensitive to the line voltage and current distortion. Moreover, these protection circuits are often costly and, therefore, it is hard to meet the commercial requirements. A low-cost over-current detection circuit with the contactless current transducer is designed and tested in this paper. The detection circuit is galvanically isolated from the power line and, thus, less sensitive to the line voltage distortion. The experimental results show that the proposed circuit accurately operates despite of its simple structure and low-cost electronic parts.

MPEG-2에서 H.264로의 Transcoding 과정에서 DCT 계수를 H.264 변환 계수로 변환하는 효율적인 알고리듬

김용재,이창우,Kim, Yong-Jae,Lee, Chang-Woo 한국통신학회 2007 韓國通信學會論文誌 Vol.32 No.8c

가장 최근에 표준화된 H.264/AVC 동영상 압축 부호화 방식은 기존의 방법인 MPEG-2에 비해 우수한 압축 효율을 보이지만, 아직 많은 응용분야에서 MPEG-2가 적용되고 있기 때문에 MPEG-2에서 H.264/AVC로의 변환 기법 개발이 필요하다. 본 논문에서는 이러한 변환을 위해 가장 첫 번째 단계로 볼 수 있는 DCT 계수에서 H.264 변환 계수로의 변환을 위한 효율적인 방법을 제안한다. 이러한 변환은 영상의 압축을 위한 변환기술로 MPEG-2에서는 $8{\times}8$ discrete cosine transform(DCT)를 사용하고 있고, H.264/AVC 표준안에서는 $4{\times}4$ integer transform을 사용하고 있기 때문에 필수적이다. 제안하는 알고리듬에서는 부호화 성능을 유지하면서 효율적으로 계산량을 감소시킬 수 있는 방법을 제시하고 계산량 분석과 모의실험을 통해서 이를 입증한다. The H.264/AVC video coding standard provides higher coding efficiency compared to the conventional MPEG-2 standard. Since a lot of videos have been encoded using MPEG-2, the format conversion from MPEG-2 to H.264 is essential. In this paper, we propose an efficient method for the conversion of DCT coefficients to H.264/AVC transform coefficients. This conversion is essential, since $8{\times}8$ DCT and $4{\times}4$ integer transform are used in MPEG-2 and H.264/AVC, respectively. The mathematical analysis and computer simulation show that the computational complexity of the proposed algorithm is reduced compared to the conventional algorithm, while the loss caused by the conversion is negligible.

대학신문의 진로

김용재,Kim, Yong-Jae 한국대학교육협의회 1986 大學敎育 Vol.23 No.-

Segmenting sport video gamers by motivation: a cluster analysis

김용재,Soojin Kim 한국마케팅과학회 2013 마케팅과학연구 Vol.23 No.1

Using the Uses and Gratifications paradigm, the present study examines motives for playing sport video games (SVG). Based on motivations, this study identifies segments of SVG users using a cluster analysis, and then explores potential similarities and differences between segments based upon demographic and behavioral variables. With a sample of 378 SVG users from four popular video game websites, the cluster analysis yielded two distinct clusters: Fun seekers and Fantasy seekers. Results indicated that the members of each cluster seek various gratifications from SVG use. Each cluster also was further distinguished based upon gender, marital status, and media consumption behaviors. Implications are discussed relative to virtual sport experience in the mediated environment and its corresponding marketing strategies.

낙동강 수계의 6개 댐호의 식물플랑크톤 군집구조 비교

김용재,이정호 ( Yong Jae Kim,Jung Ho Lee ) 한국하천호수학회 1996 생태와 환경 Vol.29 No.4

There were collected and investigated to the comparison of phytoplankton communities in 6 dam lakes of the Naktong River system on September, 1994. Total 260 taxa were 233 species, 19 varieties, 2 forma and 14 unidentified species, belong to 89 genera, 30 families, 5 suborders, 12 orders and 6 classes. The species number occurred were ranged from 89 taxa in lake Youngchun to 135 taxa in lake Chinyang. The standing crops were ranged from 2.9×10^6 individuals/l to 8.9×10^6 individuals/l. Chlorophyceae was counted the highest value in lake Imha, but Bacillariophyceae was enumerated the highest in other lakes. Cyclotella pseudostelligera Cl. and Grun. in V. H. was dominated (47∼73%) in lake Andong, Hapchun and Chinyang, Phacotus lenticularis (Ehr.) Stein (45.7%) in lake Imha, Fragilaria capucina Desm. (18.4%) in lake Unmun and Aulacoseira distans (Ehr.) Sim. var. alpigena (Grun. Sim. (30.4%)) in lake Youngchun. The trophic states using indicators of phytoplankton were eutrophic levels in all the lakes. The examination of trophic status by LTSI (lake trophic status index) were mesotrophic level (5.2) in lake Hapchun and eutrophic levels (5.4< ) in the other lakes.

보문호에서의 (普門湖) Pediastrum clathratum ( Schroeter ) Lemmermann ( 녹엽망 (綠葉綱) 의 천이와 (遷移) 생태형

김용재,정준 ( Yong Jae Kim,Jun Chung ) 한국환경생물학회 1993 환경생물 : 환경생물학회지 Vol.11 No.1

According to the environmental fluctuations, it was changed with not only physico-chemical factors but also biological species composition and standing crops. In this water system, the authors investigated the total standing crops, standing crops and composition ratio of each morphotype of Pediastrum clathratum from Nov. 1990 to Oct. 1991 and established the ecotype. Physico-chemical factors were changed uniformly in the steady state water system, but changed dramatically as the nonsteady state from June to Oct. 1991 by a torrential rain. Changes of standing crops of P. clathratum were ranged from the 7.0×10 exp (4)unit/ℓ in Nov. 1990 to 1×10 exp (2)unit/ℓ in Aug. and Sept. 1991. Of seasonal changes of each morphotype, A-2 morphotype occurred during the all months and showed the highest standing crops and composition ratio. Therefore, the authors treat A -2 morphotype as the ecotype (e.g. P. biwae form) by the seasonal changes of steady state, eury-adaptation, the highest standing crops and composition ratio.

임하호에서의 (臨河湖) 식물성플랑크톤 군집의 (群集) 생태학적 고찰

김용재,최재신,김도한,정준 ( Yong Jae Kim,Jae Sin Choi,Do Han Kim,Jung Chung ) 한국하천호수학회 1995 생태와 환경 Vol.28 No.1

This study was investigated the ecological study of phytoplankton community from eight stations of Imha lake on May, July, September and November in 1993. Phytoplankton was identified the total 297 taxa, which was composed of 261 species, 29 varieties, 3 forma and 4 unidentified taxa. Standing crops were ranged from 6.Ox10^5unit/l at st. 1 on May to 1.4×10^7unit/l at st. 2 on July. Dominant species were Anabaena soilitaria f. planctonica, Cyclotella comta, Cyclotella meneghiniana, Cyclotella ocellata, Cyclotella stelligera and Synedra delicatissima var. angustissima. Dominant index, diversity index and evenness index were 0.068∼0.750, 0.341∼1.367, 0.183∼0.716, respectively. In relationships between community and physico-chemical factors, chlorophyll-a concentration was showed a law coefficient with the total standing crops but a high with standing crop of C. stelligera. Water temperature was a positive relations with the total standing crops. T-P was showed a low relation with the total standing crops and a negative with A. solitaria f. planctonica. T-N and conductivity were a positive with the total standing crops and standing crop of Bacillariophyceae. This lake was the oligotrophic or mesotrophic type on May but converted from mesotrophic to eutrophic type at all stations on July, September and November by comparison with phytoplankton community and physico-chemical factors.

임하호의 식물 플랑크톤 군집구조

김용재,최재신,김한순 ( Yong Jae Kim,Jae Shin Choi,Han Soon Kim ) 한국하천호수학회 1997 생태와 환경 Vol.30 No.4

Phytoplankton communities are investigated at four stations in Lake Imha from March, 1992 to November, 1994. Phytopalnkton are identified from 234 taxa in 1992 to 302 taxa, in 1994. Standing crops are the highest value in 1992 and the lowest value in 1993, and slowerly increased in 1994. Dominant species are Cyclotella pseostelligera and 13 taxa. Among them, Anabaena solitaria f. planctonica is bloomed during the season the high Total-N/Total-P ratio. This result is guessed the difference between the water environment of Korea and other nations.

보행자보호 시험용 Flex-PLI의 특성 및 소형차 대응 구조 연구

김용재,진욱,김동선,Kim, Yong Jae,Jin, Wook,Kim, Dong Sun 한국자동차안전학회 2012 자동차안전학회지 Vol.4 No.2

In 2014 Flex-PLIfor the pedestrian protection will be applied to NCAP test. The most significant feature of Flex-PLI is constructed with segmental bone cores for the femur and tibia regions. So it can be more reproducible by representing pedestrian injuries such as knee ligament and tibia injury during the pedestrian crash against vehicle. In this paper, Analyzed the characteristics of Flex-PLI through the structural analysis and the test results by using Flex-PLI for our compact vehicles. Finally countermeasures into compact vehicle were proposed to fulfill the injury criteria of Flex-PLI.

An Optimal Incentive-Compatible Pricing for Congestible Networks

김용재,Kim, Yong-Jae 한국경영정보학회 1997 Asia Pacific Journal of Information Systems Vol.7 No.3

Pricing information services, where congestion can threaten the efficient operation of information systems, has been studied in economics and information systems literature, Recent explosion of the Internet ana proliferation of multimedia content over the Internet have rekindled the research interest in designing pricing schedules for differentiated information services, In order for the information system to effectively serve users having heterogeneous needs, pricing rules for discriminated services should be considered. At the same time, when individual users' interest does not align with that of the organization that individual users belong to, organization-wide pricing policy should be devised to improve the value of the services rendered by the system. This paper, using a priority queuing model, addresses the need for such on incentive-compatible pricing for different information services.