• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.4
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• pp.537-545
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• 2013

The elastic recovery of a metal seal is a factor that can be used to assess its sealing performance. In this study, a compliant mechanism topology optimization has been performed to find a structure of a metal O-ring seal that can maintain excellent sealing performance with a maximized elastic recovery over extended operation. An evolutionary structural optimization (ESO) was used as a topology optimization algorithm with two different types of objective functions considering both flexibility and stiffness. In particular, a circular design domain was adopted to consider the outer shape of the metal O-ring seal. The elastic recovery of the optimal topology was calculated and compared to that of a commercial product.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.8
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• pp.18-24
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• 2011

A new problem happens with the evolution of TSV based 3D IC design. The bonding process takes place which follows with the testing of design for proper connectivity in the absence of TSV redundancy. In order to achieve good yield, the design should be tested with redundancy TSV. This paper presents a wrapper cell design for redundancy TSV interconnect test. The design for test technique, in terms of hardware and software perspectives is described. The wrapper cell with hardware design can use original test patterns. However, software design has less area overhead.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.11
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• pp.1796-1801
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• 2001

For micro-machines, very few design methodologies based on optimization hale been developed so far. To overcome the difficulties of design optimization of micro-machines, the search method for multi-dimensional design window (DW)s is proposed. The proposed method is defined as areas of satisfactory design solutions in a design parameter space, using both continuous evolutionary algorithms (CEA) and the modified K-means clustering algorithm . To demonstrate practical performance of the proposed method, it was applied to an optimal shape design of micro electrostatic actuator of optical memory. The shape design problem has 5 design parameters and 5 objective functions, and finally shows 4 specific design shapes and design characters based on the proposed DWs.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.324-329
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• 2006

PTT(Push-To-Talk)란 모든 IP기반의 유, 무선 통합 인터넷 환경으로 진화하고 있는 이동통신망을 통하여 음성 및 텍스트 기반의 일대일 및 그룹 즉시 통신을 제공하기 위한 서비스이다. 스위치를 누르고 말하면서 즉시 의사소통을 할 수 있으므로 일반적인 통화 유형의 대기 시간에 비해 매우 빠른 통화 서비스를 제공함에 따라 각 업체 및 사무실에서 사용하고 있으며 카메라폰에 이은 새로운 어플리케이션으로 부상하고 있다. 현재 이동통신망은 기본의 TDM 방식의 코어 망에서 IP방식의 코어 망으로 천이하고 있으며, 인터넷의 보급과 확산에 따른 인터넷 기술의 발전과 IMT-2000, WIBRO 등의 시스템 도입에 의해 점차 이동통신망 내의 모든 NE를 권고하고 있다. 그러나 무선망에서의 음성 통신은 기존의 통신망에서 보다는 대역폭을 많이 차지하는 단점이 있다. 또한 통화 연결에서 1:1이 아닌 1:N의 관계에 의해 통화 연결이 폭발적으로 일어나기 때문에 대역폭의 확보가 필요하며 안정적인 주파수 사용률 확보가 필요하다. 따라서 본 논문에서는 VoIP망에서의 SIP를 이용한 PTT를 서비스를 설계하고 위와 같은 문제점을 해결하기 위하여 ROHC 알고리즘을 적용하여 PTT 서비스를 설계한다.

• Informatization Policy
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• v.24 no.4
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• pp.68-78
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• 2017

Malicious codes are currently becoming more complex and diversified, causing various problems spanning from simple information exposure to financial or psychologically critical damages. Even though many researches have studied using reverse engineering to detect these malicious codes, malicious code developers also utilize bypassing techniques against the code analysis to cause obscurity in code understanding. Furthermore, rootkit techniques are evolving to utilize such bypassing techniques, making it even more difficult to detect infection. Therefore, in this paper, we design the analysis process as a more agile countermeasure to malicious codes that bypass analysis techniques. The proposed analysis process is expected to be able to detect these malicious codes more efficiently.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.2
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• pp.178-182
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• 2011

Generally in order to reduce the steel weight of stiffened plate, stiffener spaces tend to be narrow and the plate gets thin. However, it will involve more fabrication cost because it can lead to the increase of welding length and the number of structural members. In the yard, the design which is able to reduce the total fabrication cost is needed, although it requires more steel weight. The purpose of this study is to find optimum stiffener spaces to minimize the fabrication cost for the cargo tank of LPG Carriers. Global optimization methods such as ES(Evolution Strategy) and GA(Genetic Algorithm) are introduced to find a global optimum solution and the sum of steel material cost and labor cost is selected as main objective function. Convergence degree of both methods in according to the size of searching population is examined and an efficient size is investigated. In order to verify the necessity of the optimum design based on the cost, minimum weight design and minimum cost design are carried out.

• Annual Conference of KIPS
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• 2018.10a
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• pp.5-7
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• 2018

VLSI(Very large scale integration) 기술을 통한 트랜지스터의 소형화를 통해 CMOS 집적 회로의 성능은 지속적으로 발전해 왔다. 이와 같은 기술 발전에 따라 집적 회로를 구성하는 디지털 논리 요소 또한 진화를 하고 있다. 디코더는 부호화된 정보를 다시 부호화되기 전으로 되돌아가는 처리를 하는 디지털 논리 요소이며 컴퓨터 설계에서 많이 사용되는 핵심 요소이다. 본 논문에서는 양자점 셀룰라 오토마타(Quantum Cellular-Automata, QCA)를 사용하여 인에이블 입력을 가진 2-to-4 디코더를 제안하였다. 4-입력 유니버설 게이트의 하나의 입력을 1로 고정시켜 3-입력 NOR 게이트로 사용하며, 입력 값 X와 입력 값 Y의 중복된 배선 수를 감소시키고 한 배선으로 두 게이트에 입력을 연결하여 디코더의 배선 수와 배선 교차부를 최소화한다. 제안안하는 4-to-2 인에이블 디코더는 기존 디코더보다 셀의 개수와 클럭수를 감소시켜 디코더의 성능을 더 효율적으로 향상시켰다. 이를 통해 고속 회로 설계에 활용 및 높은 성능을 기대 할 수 있으며 QCA 연구에 기여할 수 있을 것으로 전망 한다.

• Journal of Korea Multimedia Society
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• v.9 no.8
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• pp.1076-1085
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• 2006

It is difficult to design a component to satisfy several domain requirements and almost impossible to support a specific business logic completely. To satisfy this requirement, there need white box components rather than black box components. So, in this paper, we propose the variability design technique and the customization technique that can support the various requirements of domains. The initial variability of the component is designed at the CD (component development) phase and the customization technique is used for further application of the variability. In the paper, the behavior variability design and customization techniques are used for altering component behavior. As the components that have been developed using the variability technique can easily be re designed during the development of the applications, the variability of the components can be generalized further.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.389-394
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• 2017

In a conventional ship structure, stiffeners with an asymmetric section, such as inverted angles, are used widely despite the disadvantage of strength compared to the stiffeners with a symmetric section, such as a built-up T. On the other hand, T-type built-up members are attracting more attention than L-type inverted angles due to the increased size of ships. The purpose of this study was to develop an optimal design program for a built-up T, and apply an evolution strategy as an optimization technique. In the optimization process, the gross thickness concept was adopted for the design variables and objective function, and the constraints are set up based on HCSR (Harmonized Common Structural Rules). Using the developed program in this study, the optimal stiffener design was carried out for 300K VLCC and 158K COT of which the orders were obtained lately. The optimal results revealed the weight reduction effect of 144 tons and 60 tons, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.51-56
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• 2016

Corrugated bulkheads have many advantages compared to stiffened bulkheads, and they have thus been used for the cargo tank bulkheads of commercial vessels, such as bulk carriers, product oil carriers, and chemical tankers. Various studies have been carried out to find the optimum corrugation shape for bulk carriers, but optimum design studies for chemical tankers with bulkheads made of high-priced materials are scarce. The purpose of this study is to develop a minimum weight design method for horizontal corrugated bulkheads for a chemical tanker. An evolution strategy (ES) that searches for a reliable global optimum point was applied as an optimization technique, and the structural safety of the optimum design was verified through structural analysis using the finite element method (FEM). The results were compared with those of an existing ship, which showed a weight reduction of about 14% with equivalent structural strength.