• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.12A
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• pp.1759-1765
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• 2000

공기 갭을 갖는 일축성 기판위에 마이크로 패치 안테나의 공진 주파수가 full-wave approach와 모멘트 계산법을 이용하여 연구되었다. 일축성 매질내의 구성관계식을 통하여 제안된 구조에서의 파수영역 다이애딕 그린 함수를 유도하였으며 이 결과로부터 전계 적분 방정식을 수식화하였다. 갤러킨 모멘트법을 사용하여 전계 적분 방정식을 이산화 하였으며 기저함수의 선택은 수치 해석적 수렴을 고려하여 패치 위의 실제 전류밀도와 가장 유사한 형태인 정현적 기저함수를 선택하였다. 전사모의 실험 결과의 타당성을 검증하기 위해서 기존의 결과와 비교하여 일치된 결과를 얻었다. 공기 갭의 두께와 패치 길이, 이방성 비의 변화에 따른 공진 주파수가 제시되고 분석되었다.

• Journal of Communications and Networks
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• v.17 no.5
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• pp.463-472
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• 2015

This paper considers a limited feedback system for two-way wireless relaying channels with physical network coding (PNC). For full feedback systems, the optimal structure with the PNC has already been studied where a modulo operation is employed. In this case, phase and power of two end node channels are adjusted to maximize the minimum distance. Based on this result, we design new quantization methods for the phase and the power in the limited feedback system. By investigating the minimum distance of the received constellation, we present a code-book design to maximize the worst minimum distance. Especially, for quantization of the power for 16-QAM, a new power quantization scheme is proposed to maximize the performance. Also, utilizing the characteristics of the minimum distance observed in our codebook design, we present a power allocation method which does not require any feedback information. Simulation results confirm that our proposed scheme outperforms conventional systems with reduced complexity.

• Journal of Communications and Networks
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• v.16 no.2
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• pp.110-120
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• 2014

This article proposes a spectrum sharing method which can avoid the mutual interference in both primary and secondary systems. The two systems make them a priority to use two single-dimension orthogonal signals, the real and imaginary pulse amplitude modulation signals, if the primary system is not in outage with this use. A secondary transmitter is selected to be the primary relay and the active secondary source to perform this. This allows a simultaneous spectrum access without any mutual interference. Otherwise, the primary system attempts to use a full two-dimensional signal, the quadrature amplitude modulation signal. If there is no outage with respect to this use, the secondary spectrum access is not allowed. When both of the previous attempts fail, the secondary system is allowed to freely use the spectrum two whole time slots. The analysis and simulation are provided to analyze the outage performance and they validate the considerable improvement of the proposed method as compared to the conventional one.

• Journal of the Korea Society of Computer and Information
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• v.4 no.4
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• pp.57-68
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• 1999

The purpose of this study is to build a description technique and to make a simulator, which can simulate and verify the behavior of gate level digital system. To get the object code from the input description language, we build a translator. To do this, we used YACC of the UNIX parser generator. and made an intermediate code in the mid-process between translator and simulator to extend the range of application. For experimental models. we used the Full-Adder and Modulo-3 Counter.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.928-935
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• 2018

In this paper, a compact fully printable bandpass filter is suggested for a low-frequency channel 3.2 GHz ~ 3.7 GHz in the Ultra-Wideband (UWB) communication system. It is featured with a small geometry of $0.5{\lambda}_g/15$ and a low insertion loss despite using FR4 as a cheap substrate of a high dielectric loss. This is made possible by generating zeroth-order-resonance (ZOR) from one cell comprising two series resonances obviously separated from one shunt resonance as a third-order bandpass filter. Especially, the series resonance elements are combined with spur-lines bent by 90 degrees, which makes the port-impedance matched well and eliminates spurious hikes in the stopband, while the overall size remains almost unchanged. The design is carried out by setting up the equivalent circuit and the circuit simulation is checked by the full-wave EM analysis. The structure is manufactured and measured to show that the circuit modeling and EM simulation results agree with the measured data.

• Korean Journal of Agricultural Science
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• v.25 no.2
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• pp.343-350
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• 1998

This paper is aims at identifying the minimum farm size of the greenhouse vegetable cooperatives. Farm cooperative is one of the institutional measurments for the seeking of economy of scale which could not be found in family farm. In this paper 5 cooperatives and 5 farmhouseholds which have been managed vegetable greenhouse were surveyed. The results are as follows; First, cooperatives had 29.3% less on the fixed costs, and received 43% more on prices than general vegetable farmhouseholds. This means that the cooperatives have economy of scale. Second, to establish full organized coopratives, cooperative sizes must be more than 4,582 pyung, considering the government target which will be loaned 80% goverment loan of total facility costs with no subsidy.

• Nuclear Engineering and Technology
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• v.37 no.3
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• pp.231-244
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• 2005

In recent decades, significant effort has led to risk-informed improvements to regulation. Performance-based approaches also promise significant gains in efficiency (level of safety versus effort). However, significant work remains to be done before performance-based approaches realize their full potential in regulation of nuclear power plants. This paper reviews key concepts related to performance-based regulation, discusses some applications of performance-based approaches, and identifies issues that still need to be addressed. Realistic, experience-based models of licensee performance are still lacking; this makes it difficult to assess the prospective effectiveness of any given regulatory approach, in light of the performance issues that it will actually face. Also, while 'compliance' is an intuitively straightforward concept to apply within a prescriptive implementation, its analog in a performance-based approach remains unclear. An overarching theme of the paper is that formal methods of decision analysis are very helpful in developing appropriate regulatory approaches, especially performance-based ones; this theme is illustrated at several points.

• Proceedings of the Korean Society of Computer Information Conference
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• 2010.07a
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• pp.187-189
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• 2010

본 논문에서는 현재 의료부분에 많은 혜택을 주는 PACS라는 시스템을 중소병원에 맞게 설계하였다. PACS는 초기 도입 비용과 불확실한 투자효과에 의해서 많은 개인, 중소병원들이 도입하기 어려워하는 시스템 중 하나였다. 그러한 문제점으로 현재 대형병원에서만 사용 중인 PACS를 중소 병원급 PACS 시스템으로 연구하는데 있다. 본 논문에서는 기존의 병원 정보 시스템을 수용하면서도 Full PACS의 네트워크 관리모듈의 비중과 시스템 연동을 위한 WorkList Server 기능을 제한하고 특정기기에 대한 생산성 향상을 목적으로 전체가 아닌 단위별로 운영되는 중소병원용 Departmental PACS에 대해 기술하였다.

• Journal of Korea Society of Digital Industry and Information Management
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• v.15 no.4
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• pp.137-148
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• 2019

This paper is designed to examine the effectiveness of Computational Thinking and programming awareness by designing and applying programming classes using Havruta. In the present society, where the Fourth Industrial Revolution was in full swing, the capacity to be equipped has changed, and the education has been changed accordingly. Programming education is logically capable of thinking and improves comprehensive problem solving skills. This direction of programming education allows us to get ideas for solving problems based on computing thoughts and to create our own creative results. However, because they require the grammar of the programming language and many additional abilities, they are not easy for learners, and individual differences in competencies make learning less immersive and interesting. In this paper, to solve the problems of the uniform programming class, this study is designed and applied to the class applying the Jewish traditional teaching method, Havruta's teaching method, to find out the effect of computing thinking and programming perception.

• ETRI Journal
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• v.27 no.6
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• pp.708-712
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• 2005

We propose a computational reconstruction technique in large-depth integral imaging where the elemental images have information of three-dimensional objects through real and virtual image fields. In the proposed technique, we reconstruct full volume information from the elemental images through both real and virtual image fields. Here, we use uniform mappings of elemental images with the size of the lenslet regardless of the distance between the lenslet array and reconstruction image plane. To show the feasibility of the proposed reconstruction technique, we perform preliminary experiments and present experimental results.