• Journal of Educational Research in Mathematics
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• v.9 no.1
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• pp.111-119
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• 1999

This paper discusses jLogic, a mathematical logic education software developed by the author. jLogic is basically a MS-Windows based software that can construct first-order models, formulas and thet their satisfiablity. Logical formulas are easily input by a "keyboard" maintained by jLogic. A special finite model, called the "Toy World" can be visually cinstructed and modified. The user is supposed to answer the following 3 questions about the selected logical expression: 1. Is it a grammatically correct logical formula? 2. Is it a sentence that has a definite truth value? 3. Is th sentence true or false? When the user inputs his answer in the "Inspector window" and then presses the OK button, jLogic instantly tests the validity of the answer and tells the user the result. jLogic is freely downloaded from http://gauss.kyungpook.ac.kr/~jlogic/

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.242-245
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• 2005

The rotating flow in the space between co-rotating disks is of considerable importance in information storage systems. Hard disk drivers(HDD) in computer are used extensively as data storage capacity. The trend in the computer industry to produce smaller disk drives rotating at higher speed requires an improved understanding of fluid motion in the space between disks. In this study, we have tried LES model for inner-disk flowfield to investigate the flow disturbance and the flow structure driven by co-rotating disks. The boundary pattern between inner region and outer region obtained lobe-shape structure clearly and its number has been validated on experimental data by our previous study. We obtain the spectra of velocity and pressure components with several frequencies. We revealed there are two kinds of disturbances, one is global wave propagation and another is local wave propagation on Ekman boundary layer.

• Korean Journal of Child Studies
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• v.18 no.1
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• pp.177-198
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• 1997

This study investigated the viewpoint of teachers on the desirability of computer education in the early childhood classroom. The subjects were 8 kindergarten teachers in Seoul and Kyong'gi Province who used computers in the classroom. Nondirective and open-ended interview methods were used for data collection. Five steps or stages of viewpoints were found: step1-teachers want to have computers in the classroom but have no particular purpose in mind; Step 2-teachers want the children to play with the computers as if it were a toy; Step 3-teachers want to use any programs that are in the computer; Step 4-teachers want to use the computer more purposefully for educational goals; Step 5-teachers want to unify the early childhood curriculum through the multi-media system.

• Proceedings of the Safety Management and Science Conference
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• 2011.04a
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• pp.657-662
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• 2011

어린이 장난감은 과거보다 더 안전성의 필요가 되고 있다. 현대 사회의 가족변화로 인한 구성원으로 인하여 어린이가 귀한 존재가 입장이 되었기 때문이다. 이에 따른 어린이 용구에 대한 관심의 집중도가 높아졌으며 장난감에 대한 인식 변화와 안전성을 추구하고자 하는 노력도 많이 커졌다. 이는 어린이들이 장난감을 가장 많이 신체로 접촉하고 있기 때문이다. 장난감의 특성상 어린이, 특히 유아들이지만 입에 물거나 피부에 문지르고 소리나는 것에 민감하고 장난감의 재질에 따른 향, 촉감 등에 반응할 수 있기 때문이다. 이는 어린이의 처음 부딪히는 감각의 느낌과도 연결되어 감각의 기능에서 발전을 가져올 수 있다고 본다. 어린이들의 연령층에 따라 표현력이 부족하기 때문일 것이므로 어린이 장난감의 안전성에 어른들이 주의해야할 이유라고 여긴다. 즉 어린이 장난감의 안전성을 추구할 수 있는 어린이뿐만 아니라 제2의 소비자인 부모, 친척, 친지, 어린이와 연관된 직종의 어른들일 것이다. 장난감의 시장은 서구보다 발전되지 않았지만 근래에 들어 어린이 장난감은 중국이나 동남아에서 제조되어 한국으로 들어오는 경우가 많다. 따라서 안전성에 대한 인식의 제고와 실질적 노력 추구가 더욱 더 필요하다.

• Korean Journal of Plant Resources
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• v.17 no.2
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• pp.135-138
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• 2004

To determine the optimal transplanting time of wanggol in southern areas of Korea, wanggol c.v. Gangsan the highest yielding variety was grown under three different tansplanting times. Yield components such as stem length, number of tillers, number of heading stem and stems diameters were the highest at the transplanting time of May 20. Plants sown of Mar 30 showed the highest dry cortex and medulla yield. Judging from the results reported above, at optimum transplanting time combined with sowing time toy yield of wanggol (cyperus iwassaki Makino) seemed to be the time of May 20 and Mar. 30.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.1120-1122
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• 2017

IoT(Internet of Things) 기술이 접목 된 스마트 완구는 다양한 센서의 결합으로 점차 고도 지능화 되며 더 많은 서비스를 제공하고 있다. 스마트 완구는 단일 서비스 제공에서 다중 사용자 간 데이터 교환 기술로 발전하여 상호 작용을 위한 서비스 연구도 함께 이루어지고 있다. 이를 위해 국내 통신 망을 이용한 스마트 완구 서비스 플랫폼이 출시되는 등의 다양한 연구가 이루어지고 있으나 사용자 입장에서의 상호 교감 및 콘텐츠 서비스 기술에는 다소 부족한 내용이 있다. 이에 본 연구에서는 클라우드 서비스를 기반으로 스마트 완구를 이용하는 이용자 간의 상호 교감형 커뮤니케이션을 지원하기 위한 스마트 완구의 서비스 플랫폼을 설계하는 내용을 기술한다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.5
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• pp.581-588
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• 1998

An experimental study of the absorption process of water vapor into Lithium Bromide solution was performed. For the purpose of development of high performance absorption chiller-heater utilizing Lithium Bromide solution as working fluid, the absorber is the most effective to improve the performance of an absorber because it requires the largest heat transfer area in an absorption chiller-heater system. This paper introduces bare tube and floral tube for the absorber of absorption chiller-heaters. floral tube has higher heat and mass transfer performance than bare tube conventionally used in absorbers and the it is expected to perform high heat and mass transfer. This paper will provide important information on the selection of absorber tubes in commercial absorption chiller -heaters.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.433-436
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• 2000

In this paper, we present two types of digital image stabilization (DIS) schemes for mobile video communications. In the first scheme, the DIS system, which is used as a preprocessor of the video encoder, compensates the camera’s undesirable shakes before encoding. This method can reduce the bit rate of encoded video sequence by attenuating the prediction error to be encoded. In the second proposed scheme, the DIS system is coupled with the video decoder. The second scheme uses the K-means clustering algorithm to estimate the camera motion using motion vectors decoded from the received video stream. Simulation results show that the first scheme improves coding efficiency, while the second scheme is computationally efficient since it does not require motion estimation.

• Korean Journal of Child Studies
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• v.21 no.4
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• pp.197-210
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• 2000

This integrative review of research on the role of toys in the pretend play of young children investigated claims about the relative effects of abstract or unrealistic compared with concrete or realistic toys. Researchers and educators acknowledge the benefits of pretend play as an expression of the child's capacity of symbolic functioning and they attend to strategies for promoting pretend play at each stage of its development, including the selection and presentation of playthings. Highly structured or realistic toys were once thought to impede pretend play because they can only be used for a single intended purpose whereas less structured toys are pliant and hold the child's interest over longer periods of time as new ideas are tried out. However, the present review suggests that realistic toys are effective for very young children who still have limited representational capacity, and that realistic toys continue to give impetus to make-believe even for kindergarten children.

• 전자공학회논문지 IE
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• v.44 no.1
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• pp.10-14
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• 2007

Analytical expression for breakdown voltages of InP diodes is induced by employing the effective ionization coefficient extracted from ionization coefficients for electron and hole in InP. The analytical results for breakdown voltage are compared with numerical and experimental results for the doping concentration, $N_D=6\times10^{14}cm^{-3}\sim3\times10^{17}cm^{-3}$. The analytical results show good agreement with the numerical data. Good fits with the experimental results are found for the breakdown voltages within 10% in error at each doping concentration.