• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.281-285
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• 2007

일반 공학용계산기를 모델로 WIPI를 이용한 어플리케이션인 모바일 공학용계산기를 개발하였다. 모바일 공학용계산기는 사용빈도가 높은 함수연산(삼각함수, log, $\surd$(루트), $\Pi$(파이), !(팩토리얼), 제곱 등)을 지원하며 식의 저장(Save), 불러오기(Load) 기능으로 이용의 편리함을 더하였다. 입력받은 문자열을 숫자로 변환하여 한자리씩 계산한 후 문자열로 재결합하는 구조로 결과값의 길이에 대한 제한 없이 출력이 가능하다. 성능은 PC나 일반 공학용계산기의 처리속도와 결과의 정확도면에서 뒤떨어지지 않는다. 모바일 공학용계산기는 휴대폰에 탑재되어 이동성이 탁월하며 언제어디서나 사용가능하고, 한번의 다운로드로 수명이 영구적이다. 또한 소프트웨어 업그레이드로 프로그램의 확장성이 특징이다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2008.06a
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• pp.169-174
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• 2008

본 논문에서는 사용자가 원하는 수식을 휴대 전화기의 사용자 입력 인터페이스를 통해 한꺼번에 모두 입력하면, 입력받은 수식을 분석하고 계산 및 연산자 우선순위를 파악한 후에 순차적으로 계산을 수행해주는 휴대 전화기용 공학 계산기 개발에 대하여 기술한다. 기존의 계산 기능을 지원하는 휴대 전화기에서는 수식 전체를 한꺼번에 입력받지 못하는 단점으로 인하여 간단한 수식 계산을 수행할 때에도 여러 번의 수식 입력을 해야 하기 때문에 하나의 수식을 계산하는데 시간이 많이 소모되는 불편함을 가지고 있었다. 또한 입력받은 수식을 저장할 메모리의 부족과 수식 분석 기능 등의 부재로 인해 현재까지 휴대 전화기용 공학 계산 기능은 제대로 서비스되지 못하고 있다. 그러므로 본 논문에서는 이러한 문제점들을 개선하여 모든 수식을 한꺼번에 입력하고 계산 및 연산자 우선순위에 의하여 실시간으로 결과 값을 확인할 수 있는 시스템을 개발하였으며, 향후 공학용 계산기가 필요한 학생 및 일반인들에게 매우 유용하게 사용될 수 있을 것으로 기대한다.

• The Mathematical Education
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• v.45 no.1 s.112
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• pp.35-60
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• 2006

In the seventh mathematics curriculum, the use of technological tools including calculator and computer are generally recommended through the seventh subjects related to mathematics emphasized, and especially in 'Applied Mathematics' subject, their use are more strongly emphasized and reflected. The total four kinds of textbooks of Applied Mathematics includes contents on their use. This study investigates what are contents on calculator use, how they are developed and constructed in Applied Mathematics Textbook. Furthermore, this study is focused on the analysis and comparison on those factors of four kinds of textbooks. Based on these results, this study ultimately hope to suggest how effectively calculator use be developed and constructed in textbook both in Applied Mathematics and the other mathematics subjects.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.2
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• pp.25-30
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• 1985

This paper proposes an algorithm to simplify Boolean functions into near minimal sum-of-products for Programmable Logic Arrays. In contrast to the conventional procedures, where the execution time depends on the number of variables, the execution time by this procedure depends on the degree of consensus of base minterms. Thus as the number of variables is increased, the difference of CPU time becomes larger using this new Procedure than using other procedures and consequently the executable range of input function increasing. The algorithm has been implemented on CYEER 170-740 and it's results were compared with those using Arvalo's algorithm.

• Journal of Energy Engineering
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• v.3 no.1
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• pp.44-53
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• 1994

STELF 기술의 핵심의 되는 IMPEX 블록의 잔류 공급률, 겉보기 밀도, 흑연의 혼합비 등 여러 가지 주요 변수가 블록의 특성에 미치는 영향을 조사하여 실제 반응기를 설계하는데 필요한 자료를 구하였다. 대표적인 염들에 대하여 물질전달 및 열전달 문제를 일으키지 않는 영역에서 최소의 부피를 갖는 값들을 계산하였고, 각각의 물질이 갖는 특정 전도도에서의 최대 냉방 및 난방 에너지 밀도를 계산하였다. 이로부터 얻은 값들을 8시간 동안 사용할 수 있는 6kW 냉방용 반응기 설계에 적용하여 본 결과 SrCL2-8/1 NH3가 최적의 염임을 확인하였다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.5
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• pp.17-30
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• 2001

In this paper, we implemented a scalar multiplier needed at an elliptic curve cryptosystem over standard basis in $GF(2^{163})$. The scalar multiplier consists of a radix-16 finite field serial multiplier and a finite field inverter with some control logics. The main contribution is to develop a new fast finite field inverter, which made it possible to avoid time consuming iterations of finite field multiplication. We used an algorithmic transformation technique to obtain a data-independent computational structure of the Extended Euclid GCD algorithm. The finite field multiplier and inverter shown in this paper have regular structure so that they can be easily extended to larger word size. Moreover they can achieve 100% throughput using the pipelining. Our new scalar multiplier is synthesized using Hyundai Electronics 0.6$\mu\textrm{m}$ CMOS library, and maximum operating frequency is estimated about 140MHz. The resulting data processing performance is 64Kbps, that is it takes 2.53ms to process a 163-bit data frame. We assure that this performance is enough to be used for digital signature, encryption & decryption and key exchange in real time embedded-processor environments.

• Journal of Aerospace System Engineering
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• v.16 no.6
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• pp.106-113
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• 2022

The structural safety of the basic design model of the linear actuator for the individual blade pitch control of eVTOL personal aircraft was investigated. Stress analysis based on the finite element method was conducted, and the margin of safety was calculated to examine the structural safety under stall load conditions. Additionally, fatigue analysis was conducted to evaluate the fatigue life of the linear actuators under operating conditions. The load history with the blade pitch angle was calculated using multi-body dynamics analysis, and the static load analysis was used to obtain the stress distribution for the rated load. As a result, it was confirmed that the safety margins exceeded zero, and the fatigue lives of all linear actuator components exceeded 107 cycles, indicating a safe structural range.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.105-110
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• 2014

Feature-oriented software product line engineering is to develop various products by developing product line core assets in terms of features and composing those features. However, the developed product may not behave correctly if the feature interaction problem has not be properly taken into account during the feature composition. This paper proposes techniques for identifying and modularizing undesirable feature interactions effectively. The scientific calculator product line is used for evaluating the applicability of the proposed method.

• Journal of Aerospace System Engineering
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• v.17 no.4
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• pp.126-132
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• 2023

Recently, the consideration of eco-friendly technology to reduce greenhouse gas is being emphasized in the aviation field. Various studies for applying electro-mechanical actuators that control mechanical linear and rotational movements using electricity as the primary power source are in progress. In this study, the fatigue analysis of the electro-mechanical actuator for the front wheel steering of a single aisle aircraft was carried out. A unit load stress table was constructed for the vulnerable part selected through structural analysis, and the representative stress for each load profile was calculated using the unit load stress table constructed for the vulnerable part. Then, individual profiles of representative stress group were extracted from continuous load profiles by applying the rainflow counting method. The damage of each profile was calculated by applying the S-N diagram. Finally, the total damage in the vulnerable parts was calculated by the linear cumulative damage law, and the fatigue life of the electro-mechanical actuator for the front wheel steering of a single aisle aircraft was evaluated.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.10
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• pp.41-49
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• 2013

This paper suggests the dielectric resonator antenna using LTCC process for mm-wave car radar system. In this paper, dielectric resonator antennas (DRA) operated in 76-77 GHz frequency band are designed. And, using the LTCC process, the structures of dielectric resonator with SRR (split ring resonator) inside and those of dielectric resonator with probe inside are suggested. Linear polarization antennas and circular polarization antenna are designed for the DRA with probe inside. Three kinds of the DRA antennas are designed and their characteristics are calculated using CST RF simulation tool. The designed antennas are fabricated and measured and the measured results are compared with calculated results. The measured operating frequencies of DRAs are within 76 GHz to 77 GHz, which are close to the calculated results, and the measured gains are about 8.15 dBi to 10.82 dBi.