• Title/Summary/Keyword: 최적화프로그램

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Design Considerations on Large-scale Parallel Finite Element Code in Shared Memory Architecture with Multi-Core CPU (멀티코어 CPU를 갖는 공유 메모리 구조의 대규모 병렬 유한요소 코드에 대한 설계 고려 사항)

  • Cho, Jeong-Rae;Cho, Keunhee
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.2
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    • pp.127-135
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    • 2017
  • The computing environment has changed rapidly to enable large-scale finite element models to be analyzed at the PC or workstation level, such as multi-core CPU, optimal math kernel library implementing BLAS and LAPACK, and popularization of direct sparse solvers. In this paper, the design considerations on a parallel finite element code for shared memory based multi-core CPU system are proposed; (1) the use of optimized numerical libraries, (2) the use of latest direct sparse solvers, (3) parallelism using OpenMP for computing element stiffness matrices, and (4) assembly techniques using triplets, which is a type of sparse matrix storage. In addition, the parallelization effect is examined on the time-consuming works through a large scale finite element model.

Preliminary Design of a Ship by the Knowledge-Based Optimum Design System (지식기반 최적설계시스템에 의한 선박 초기설계)

  • Dong-Kon Lee;Soo-Young Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.33 no.1
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    • pp.161-172
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    • 1996
  • Although conventional computer programs use efficient and precise optimization algorithms, they can not emulate the problem solving capabilities of human experts. A design optimization process involves a number of tasks which require human expertise and experience. Traditional optimization systems have concentrated on numerical aspects of a design process and have not been successful in integrating the numerical parts with human expertise. On the other hand, most knowledge-based systems focus on symbolic reasoning and have been little concerned with the numerical processes. The objective of this paper is to develop a knowledge-based multiobjective optimum design system which has the capabilities of knowledge processing and numerical computation by integrating the multiobjective optimization method and the knowledge-based system. The knowledge-based system for symbolic processing is developed. Rules for knowledge representation and the inference mechanism of the system are written in LISP. The knowledge-based multiobjective optimum design system is finally developed by integrating the multiobjective optimization method and the knowledge-based system by applying shell programming technique. The system is applied to an optimum design model of a LNG carrier in the preliminary design stage. It is found that the system well simulate design variables and objective functions of the design model.

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Performance Analysis of Cross-Layer Handoff Scheme in IP-Based Next-Generation Wireless Networks (IP기반 차세대 무선 네트워크에서의 교차계층 핸드오프 기법의 성능 분석)

  • Lee, JaeSuk;Jeong, Jongpil
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38B no.6
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    • pp.454-472
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    • 2013
  • The development of wireless network technology and the increasing use of wireless networks to mobile users with a variety of wireless network systems has arisen. Wireless sensor networks, they can be nested together, and the need to switch between the network, depending on your needs. Next Generation Wireless Networks(NGWN) gives the mobile user a wide coverage and optimized service etc. Previous hand off management protocol is not enough to secure support of the NGWN application program. Cross-layer Handoff(CLH) protocol technique has been developed to support between and inside networks of handoff management of NGWN. CLH supports mobility management in a wireless network environment and also utilizes mobility speed and handoff signaling delay information to improve the handoff performance ability. For the analysis of handoff performance ability, we analyzed sensitivity of link layer and network layer, therefore, CLH technique is suggested based on this analysis.

Critical Pathway for Spinal Stenosis Patients (척추관 협착증 환자 진료 프로세스 개발)

  • Lee, Hwan Mo;Kim, Ho Jung;Kim, Keung Nyun;Ahn, Poong Gi;Chun, Jahae;Shin, Hyun-Ju;Kim, Yang Soo;Shin, Hye Sun;Kim, In Sook;Chung, Hye Kyung;Kim, Young Ah;Chae, Hyung Ki;Park, In Young
    • Quality Improvement in Health Care
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    • v.15 no.2
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    • pp.83-86
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    • 2009
  • 연구배경: 수술적 치료가 필요한 척추관 협착증 환자들은 주로 60세 이상의 고령환자로 장기간의 입원 시 기회 감염의 증대와 불필요한 의료비의 증대를 가져오게 되며, 수술 후 환자들의 재원일수의 증가는 병원의 병상가동률을 감소시키고, 전공의에게는 불필요한 업무를 증가시킨다. 연구목적: 비용 효과면에서 최적화된 진료 지침의 개발은 불필요한 의료비의 감소 및 Hospital Induced Complication을 줄여 환자 만족도를 증진시킬 수 있으며, 각 환자에 대한 전공의 업무를 줄일 수 있다. 의료기관: 서울특별시에 소재한 2,075병상의 종합전문요양기관 연구방법: 정형외과 및 신경외과의 척추관 협착증 환자의 처방을 비교하여 최적의 표준진료지침을 개발하고 최종적으로 CP Master Program(EMR 프로그램)에 입력하여 환자에게 적용하였다. 연구결과: CP 적용 전, 후 비교를 통해 재원일수는 3.8일이 감소하였으며, 이에 따라 병상 가동률 및 진료수익이 증가했으리라고 예상되며 현재 비교 검토 중이다. 또한, CP 개발 및 CP Master Program의 사용을 통한 전공의 업무 감소에 대해 검토하고 있다.

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Numerical Study of Heat Transfer Characteristics and Thermal Stress for Enamel coating Heat Exchanger in High Temperature Firing Process (법랑코팅 열교환기에서 고온 소성공정에 따른 열전달 및 열응력에 관한 연구)

  • Choi, Hoon-Ki;Lim, Yun-Seung;Lee, Jong-Wook
    • Journal of Convergence for Information Technology
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    • v.10 no.2
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    • pp.82-88
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    • 2020
  • The purpose of this study is to obtain basic data on the optimization of firing process conditions for enamel coating in chemical heat exchanger. The method of increasing the firing temperature in order to apply enamel coating to shell & tube type heat exchanger was examined. The temperature distribution of the heat exchanger in the firing kiln was numerically calculated using a commercial CFD program. The structural safety of the heat exchanger was confirmed by thermal stress analysis using the FSI method. Numerical analysis and experimental results show that there is a problem of safety due to temperature difference when the heat exchanger at room temperature is directly put into a firing kiln at 860℃. Therefore, a preheating process is need to reduce the temperature difference. As in Case2 with fewer firing steps, the first stage preheating temperature of 445℃and the second stage firing temperature of 860 ℃are considered to be most suitable.

Electronic Spectroscopy and Ligand Field Analysis of trans-[CrX2([15]aneN4)]+(X=F,CI) (trans-[CrX2([15]aneN4)]+(X=F,CI)의 전자분광학과 리간드장 해석)

  • Jong-Ha Choi;In-Gyung Oh;Sang Hak Lee;Yu Chul Park
    • Journal of the Korean Chemical Society
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    • v.47 no.2
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    • pp.109-114
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    • 2003
  • The electronic absorption spectra of trans-$[CrX_2([15]aneN_4)]ClO_4\;([15]aneN_4$=1,4,8,12-tetraazacyclopentadecane; X=F, Cl) complexes have been interpreted using the ligand field theory. An AOMX program is used to optimize the differences between the calculated and the observed positions for the spin-allowed transition bands. The crystal field theory(CFT) parameter is directly related to the angular overlap model(AOM), normalized spherical harmonic hamiltonians(NSH), and semiempirical parameters. The various ligand field parameters are discussed in terms of their chemical significances. According to the ligand field analysis, we can confirm that the fluoride ligand is a very strong ${\sigma}-$ and ${\pi}-$donor while the chloride has weak ${\sigma}-$ and ${\pi}-$donor properties toward chromium(III) ion.

Scleral Diagnostic System Implementation with Color and Blood Vessel Sign Pattern Code Generations (컬러와 혈관징후패턴 코드 생성에 의한 공막진단시스템 구현)

  • Ryu, Kwang Ryol
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.12
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    • pp.3029-3034
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    • 2014
  • The paper describes the scleral diagnostic system implementation for human eyes by using the scleral color code and vessels sign pattern code generations. The system is based on the high performance DSP image signal processor, programmable gain control for preprocessing and RISC SD frames storage. RGB image signals are optimized by PGC, the edge image is detected form the gray image converted. The processing algorithms are executed by scleral color code generation and scleral vessels sign pattern code creation for discriminating and matching. The scleral symptomatic color code is generated by YCbCr values at memory map tolerated and the vessel sign pattern code is created by digitizing the 24 clock and 13 ring zones, overlay matching and tolerances. The experimental results for performance are that the system runs 40ms, and the color and pattern for diagnostic errors are around 20% and 24% on average. The system and technique enable a scleral diagnosis with subdividing the patterns and patient database.

Trapezoidal Gate 구조를 이용한 AlGaN/GaN HEMT의 DC 및 고내압 특성 연구

  • Kim, Jae-Mu;Kim, Dong-Ho;Kim, Su-Jin;Jeong, Gang-Min
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.151-151
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    • 2008
  • 갈륨-질화물(GaN) 기반의 고속전자이동도 트랜지스터(high electron mobility transistor, HEMT)는 마이크로파 또는 밀리미터파 등과 같은 고주파 대역의 통신시스템에 널리 사용되는 전자소자로 각광받고 있다. GaN HEMT는 AlGaN/GaN 또는 AlGaN/InGaN/GaN 등과 같은 이종접합구조(heterostructure)로부터 발생하는 이차원 전자가스(two-dimensional electron gas, 2DEG) 채널을 이용하여 캐리어 구속효과(carrier confinement) 및 이동도의 향상이 가능하다. 또한 높은 2DEG 채널의 면밀도(sheet concentration) 와 전자의 포화 속도(saturation velocity)를 바탕으로 고출력 동작이 가능하여 차세대 이동통신용 전력 증폭기로 주목받고 있다. 그러나 이론적으로 우수한 특성과 달리, 실제 소자에서는 epi 성장시의 결함이나 전위, 표면 상태에 따른 2DEG 감소 등의 영향으로 이론보다 높은 누설 전류와 낮은 항복 전압 특성을 가진다. 특히, 기존의 GaN HEMT 구조에서는 Drain-Side Gate Edge에서의 전계 집중이 항복 전압 특성에 미치는 영향이 크다. 본 논문에서는 이러한 문제를 해결하기 위해 Trapezoidal Gate구조를 이용하여 Drain 방향의 Gate Edge가 완만히 변하는 구조를 제안하였다. 이를 위해 $ATLAS^{TM}$ 전산모사 프로그램을 이용하여 Trapezoidal Gate 구조를 구현하여 형태에 따른 전류-전압 특성 및 소자의 스위칭 특성 및 Gate 아래 채널층에 형성되는 Electric Field의 분산을 조사하고, 이를 바탕으로 고속 동작 및 높은 항복 전압을 갖는 AlGaN/GaN HEMT의 최적화된 구조를 제안하였다. 새로운 구조의 Gate를 적용한 AlGaN/GaN HEMT는 Gate edge에서의 전계를 분산시켜 피크 값이 감소되는 것을 확인하였다.

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Optimization of the Integrated Seat for Crashworthiness Improvement (일체형 시트의 충돌특성 개선을 위한 최적설계)

  • 이광기;이광순;박현민;최동훈
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.16 no.4
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    • pp.345-351
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    • 2003
  • Due to increasing legal and market demands for safety in the automotive design process, the design of integrated seat is important more and mote because it should satisfy the conflict between stronger and lower weight for safety and environmental demands. In this study for crash simulations, the numerical simulations have been carried out using the explicit finite element program LS-Dyna according to the FMVSS 210 standard for safety test of seat. Since crash simulations are very time-consuming and a series of simulations that does not lead to a better result is very costly, the optimization method must be both efficient and reliable. As a result of that, statistical approaches such as design of experiments and response surface model have been successfully implemented to reduce time-consuming LS-Dyna simulations and optimize the safety and environmental demands together with nonlinear optimization algorithm. Design of experiments is used lot exploring the design space of maximum displacement and total weight and for building response surface models in order to minimize the maximum displacement and total weight of integrated seat.

Optimization of Peel Adhesion of Acrylic Pressure Sensitive Adhesive using Design of Experiments (실험계획법을 이용한 아크릴 점착제의 점착력 최적화)

  • Lee, Young Sang;Ha, Jin Kuk;Lee, Euy Soo
    • Journal of Adhesion and Interface
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    • v.9 no.1
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    • pp.22-27
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    • 2008
  • The effect of functional monomers on the acrylic pressure sensitive adhesive (PSA) property was measured. Design of experiments in order to optimal peel adhesion was applied and commercial program (MINITAB) was used. Analysis was used to mixture design (special cubic model) in response surface methodology. Optimal monomer compositions was construed by 2-EHA (0.8861), EA (0.0639), MAA (0.03) and AAm (0.02). The estimated regression equation was as follows : $$y=54.8816x_1+80.7067x_2-44.4700x_3-99.0288x_1x_2+60.7706x_1x_3-441.030x_2x_3+974.341x_1x_2x_3$$.

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