• 디자인학연구
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• 제19권1호
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• pp.335-340
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• 2006

본 연구는 주거환경 중 욕실에서 사용하는 세면대의 디자인 개발로서, 생산성 향상에 따른 생산자 만족과 사용자의 다양성 수용이라는 소비자의 만족을 동시에 충족시키는 매스-커스터마이제이션(mass-customization) 개념을 도입하여, 다양한 특성의 조합 표현이 가능한 확장성(expansibility) 기반의 디자인 개발에 관한 것이다. 제품의 속성상 특히 기능적인 부분과 감성적인 부분의 적절한 균형에 중점을 두었다. 효율적인 디자인 개발 프로세스를 위하여 사용자 행동 분석을 통해 잠재되어 있는 소비자의 욕구를 도출하였고, 전반적인 주거환경과 욕실, 세면대 디자인에 대한 트랜드 분석을 기초로 제품의 특성에 맞는 새로운 소재의 응용과 그 조합을 개발하였으며, 사용자의 다양한 조건에 따른 확장성을 높이기 위하여 모듈라 디자인(modular design)을 사용하였다.

• 전력전자학회논문지
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• 제18권1호
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• pp.54-62
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• 2013

This paper proposes a high-efficiency DC-DC converter with improved dynamic response characteristics for modular photovoltaic power conversion. High power efficiency is achieved by reducing switching power losses of the DC-DC converter. The voltage stress of power switches is reduced at primary side. Zero-current switching of output diodes is achieved at secondary side. A modified proportional and integral controller is suggested to improve the dynamic responses of the DC-DC converter. The performance of the proposed converter is verified based on a 200 [W] modular power conversion system including the grid-tied DC-AC inverter. The proposed DC-DC converter achieves the efficiency of 97.9 % at 60 [V] input voltage for a 200 [W] output power. The overall system including DC-DC converter and DC-AC inverter achieves the efficiency of 93.0 % when 200 [W] power is supplied into the grid.

• 호남수학학술지
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• 제28권1호
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• pp.31-44
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• 2006

We discuss various types of sublattice of the lattice of intuitionistic fuzzy subgroups of a given group. We prove that a special class of intuitionitic fuzzy normal subgroups constitutes a modular sublattice of the lattice of intuitionistic fuzzy subgroups.

• 호남수학학술지
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• 제30권2호
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• pp.343-358
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• 2008

The primitive orders in a quaternion algebra play a central role of the theory of Hecke operators. In this paper, we study theta series generated by Brandt matrices and its applications to almost Ramanujan graphs.

• 한국산학기술학회논문지
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• 제16권3호
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• pp.2255-2262
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• 2015

최근 저심도의 도시철도 시스템이 제안되어 지상고가 형식의 민원과 지하경전철 형식의 비경제성을 극복하기 위한 연구가 진행중이다. 본 연구에서는 저심도 지하구조물의 경제성과 시공성 확보를 위하여 가시설을 대체하는 프리캐스트 형식의 모듈식 구조체를 적용하기 위하여 영구 강성벽체와 상부 슬래브간 연결부 조인트에 대한 구조적 성능을 검증하고자 실내 재하실험을 수행하였다. 성능재하 실험결과, 가시설 대체 강성벽체와 상부 슬래브간 연결부 구조는 휨모멘트 전달구조임을 확인하였다. 특히 휨 지배를 받는 상부에서는 채널형태보다는 커플러 조합이 휨 저항 성능이 30%정도 증가하여 유리함을 확인하였으나, 성능 개선이 필요한 것으로 확인되었다.

• Journal of Power Electronics
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• 제17권6호
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• pp.1490-1499
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• 2017

The modular multilevel converter (MMC) is generally considered to be a promising topology for medium-voltage and high-voltage applications. However, in order to apply it to high-power applications, a huge number of switching devices is essential. The numerous switching devices lead to considerable switching losses, high cost and a larger heat sink for each of the switching device. In order to reduce the switching losses of a MMC, this paper analyzes the performance of the conventional discontinuous pulse-width modulation (DPWM) method and its efficiency. In addition, it proposes a modified novel DPWM method for advanced switching losses reduction. The novel DPWM scheme includes an additional rotation method for voltage-balancing and power distribution among sub modules (SMs). Simulation and experimental results verify the effectiveness and performance of the proposed modulation method in terms of its switching losses reduction capability.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권3호
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• pp.425-437
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• 2017

For efficient hardware (HW) implementation of elliptic curve cryptography (ECC), various sub-modules for the underlying finite field operations should be implemented efficiently. Among these sub-modules, modular inversion (MI) requires the most computation; therefore, its performance might be a dominant factor of the overall performance of an ECC module. To determine the most efficient MI algorithm for an HW ECC module, we implement various classes of MI algorithms and analyze their performance. In contrast to the common belief in previous research, our results show that the right-shift binary inversion (RS) algorithm performs well when implemented in hardware. In addition, we present optimization methods to reduce the area overhead and improve the speed of the RS algorithm. By applying these methods, we propose a new RS-variant that is both fast and compact. The proposed MI module is more than twice as fast as the other two classes of MI: shifting Euclidean (SE) and left-shift binary inversion (LS) algorithms. It consumes only 15% more area and even 5% less area than SE and LS, respectively. Finally, we show that how our new method can be applied to optimize an HW ECC module.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 추계종합학술대회 B
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• pp.732-735
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• 2008

RSA 암호 알고리즘의 고속 연산에 핵심이 되는 법 곱셈 (modular multiplication)을 고속으로 처리하기 위해서 몽고메리 알고리즘이 연구되고 발전되어 왔다. 이 몽고메리 알고리즘에서는 법 곱셈에 나눗셈이 들어가지 않기 때문에 빠른 법 곱셈 연산을 수행할 수 있다. 하지만, 일반 잉여 형태의 숫자를 몽고메리 표현 형태로 변환하고 이후에 결과를 다시 일반 잉여 형태로 변환하는 과정에서 별도로 연산이 필요하게 된다. 1024 비트 이상의 고비도의 RSA 연산을 수행하기 위해서는 키 비트를 워드 단위로 쪼개어 다진법 개념을 도입하여 연산할 수가 있다. 본 논문에서는 몽고메리 알고리즘을 개선시키기 위하여 오퍼랜드 스캐닝 개념을 도입한 방법을 연구하여 비교하였다. 각각의 방법은 최적화에 대한 이슈, 메모리 공간에 대한 이슈, 연산 시간에 대한 이슈를 고려 대상으로 한다.

• Journal of Welding and Joining
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• 제26권6호
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• pp.59-66
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• 2008

Recently, automobile parts progress with modularization, which a great many allied products are modularized. Therefore, the purpose of this study is to develope modular housing for modularization of steering gear. Generally, steering gear housing is composed of valve housing and rack housing, it is important to combine two housings. However, housing having the pipe shape is very sensitive to welding distortion, and welding trajectory is very complicated. In order to solve this subject, cooperative control by using robots was constructed. Further, we developed the dedicated system to suit modular housing based on it, and applied laser welding to there. Moreover, welding speed was controlled in the rapid curve section so that the defect in trajectory of housing was reduced to obtain sound weldment. Accordingly, produced housing by this way is presented enough withstanding pressure to $100kg/cm^2$, and roundness and straightness are measured about 10/100 and 0.9/100 respectively.

• 디지털산업정보학회논문지
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• 제16권2호
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• pp.1-9
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• 2020

Many cryptographic and error control coding algorithms rely on finite field GF(2m) arithmetic. Hardware implementation of these algorithms needs an efficient realization of finite field arithmetic operations. Finite field multiplication is complicated among the basic operations, and it is employed in field exponentiation and division operations. Various algorithms and architectures are proposed in the literature for hardware implementation of finite field multiplication to achieve a reduction in area and delay. In this paper, a low area and delay efficient semi-systolic multiplier over finite fields GF(2m) using the modified Montgomery modular multiplication (MMM) is presented. The least significant bit (LSB)-first multiplication and two-level parallel computing scheme are considered to improve the cell delay, latency, and area-time (AT) complexity. The proposed method has the features of regularity, modularity, and unidirectional data flow and offers a considerable improvement in AT complexity compared with related multipliers. The proposed multiplier can be used as a kernel circuit for exponentiation/division and multiplication.