• 정보처리학회논문지D
• /
• 제9D권6호
• /
• pp.1083-1090
• /
• 2002

소프트웨어개발방법론은 급변하는 정보기술변화에 따라가지 못한다. 대부분의 소프트웨어 개발 프로젝트는 구조적 또는 정보공학 방법론을 사용한다. 기존 소프트웨어 개발 방법론이 프로젝트에 적용할 기술이 반영이 안되어 있다면, 프로젝트는 비효율적으로 수행되어진다. 본 논문은 새로운 정보기술을 기존의 구조적 또는 정보공학 방법론에 용이하게 반영하여 개선하는 모델을 제안한다. 본 모델은 소프트웨어 생명주기를 단계들로 나누고 각 단계는 관점 영역으로 나누어 분할된 작은 영역에 새로 적용할 정보기술을 반영하는 분할과 정복 기법을 활용한다. 적용사례는 설계단계를 중심으로 KCC 정보통신(주)에서 사용한 클라이언트 서버 방법론 CS@RoadMap에 웹 기반 소프트웨어 개발절차를 반영하였다. CS@RoadMap방법론에 웹 기술을 반영한 Web@RoadMap방법론을 공공 프로젝트에 적용하였다.

• 한국항행학회논문지
• /
• 제27권4호
• /
• pp.457-462
• /
• 2023

파장 분할 다중 신호와 같은 대용량 광 신호를 장거리 전송하기 위하여 사용되는 MSSI (mid-span spectral inversion)와 분산 제어가 결합된 시스템에서의 융통적인 링크 구성을 제안하고 색 분산과 비선형 왜곡 보상 효과를 높일 수 있는 구체적 방법을 살펴보았다. 분산 제어 링크 구성의 융통성을 높이기 위해 제안된 분산 맵은 'random-inverse' 구조를 갖는다. 즉 광 위상 공액기까지의 전반 구획의 각 광성유 스팬의 RDPS는 랜덤하게 분포되고 후반 구획의 RDPS 분포는 전반 구획의 분포 패턴을 반전하는 구성의 분산 맵이다. 제안된 분산 맵은 RDPS의 랜덤 분포를 가지기는 하지만 결과적으로 광 위상 공액기를 중심으로 분산 프로파일이 대칭이 되는 점에 기인하여 왜곡 보상 효과가 개선되는 것을 확인하였다. 'random-inverse' 구조의 분산 맵에서 각 광섬유 스팬에 할당되는 RDPS의 크기가 큰 경우에서왜곡된 파장 분할 다중 신호의 보상 효과가 더욱커지는 것도 동시에 확인하였다.

• Investigative Magnetic Resonance Imaging
• /
• 제15권1호
• /
• pp.57-66
• /
• 2011

목적 : 0.35 Teslas의 저자장 자기공명영상 시스템에서 인체 조직의 물 성분 또는 지방 성분의 영상을 얻는데 있어서 주자장의 불균일도를 two-point Dixon 방법을 기반으로 보정하는 새로운 방법을 모색하였다. 대상 및 방법 : Two-point Dixon 방법을 사용하여 물과 지방의 위상이 동상일 때와 역상일 때의 영상들을 얻은 후 그 영상들로부터 위상과 크기의 위상 크기 결합 밀도 함수를 계산하고, 이를 통해 물과 지방의 영역을 분리하여 3차원 볼륨의 물 영역에서의 주자장의 불균일도 패턴을 분석하고 이를 반복적으로 보정하여 주자장의 불균일도를 개선하였다. 결과 : 제안한 영상 기법으로 인체의 여러 부위에서 주자장의 불균일도를 보정한 물과 지방 영상을 얻을 수 있었다. 삼차원 보정을 통하여 멀티 슬라이스 전체 영상에서 균일하게 물 또는 지방만의 영상을 얻을 수 있었다. 결론 : 위상-크기 결합 밀도 함수를 통하여 물과 지방의 영역을 분리할 수 있었고, 이를 이용하여 자장의 불균일도를 분석하고 보정할 수 있었다. 제안한 방법을 통해 주자장의 불균일도가 월등히 개선된 물 또는 지방 영상을 얻을 수 있었다.

• 전기학회논문지
• /
• 제57권12호
• /
• pp.2208-2212
• /
• 2008

This paper deals with the cost reduction design of a single-phase line-start permanent magnet(LSPM) motor. Due to high cost of the permanent magnet(PM), cost reduction can be effectively achieved by reducing PM volume. Therefore, motor characteristics according to the PM volume are calculated by using d-q axis equivalent circuit analysis, and the characteristic map is made. In the characteristic map, maximum torque and efficiency are shown according to motor parameters such as back electromotive force(back emf) and inductances; back emf represents the PM volume. Minimum back emf and inductances satisfying output performance are determined in the characteristic map. Then, motor geometry based on the prototype motor is optimized to get the determined parameters using response surface methodology(RSM) and finite element method(FEM). Through the presented cost reduction design, total PM volume is reduced to 32% of prototype model.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2001년도 춘계학술대회 논문집
• /
• pp.226-230
• /
• 2001

Electronic Speckle Pattern Interferometry (ESPI) has been recently developed and widely used because it has advantage to be able to measure surface deformations of engineering components and materials in industrial areas with non-contact. The spekle patterns to be formed with interference phenomena of scattering phenomena measure the out-of-plane deformations, together with the use of digital image equipment to process the informations included in the speckle patterns and the display consequent interferogram on a computer monitor. In this study, the experimental results of a canti-levered plate using ESPI were compared with those obtained from the simple beam theory. The ESPI results of the canti-levered plate analyzed by 4-step phase shifting method are close to the theoretical expectation. Also, out-0of-plane displacements of a spot welded canti-levered plate were measured by ESPI with 4-step phase shifting technique. The phase map of the spot welded canti-levered plate is quite different from that of the canti-levered plate without spot welding.

• 대한기계학회논문집B
• /
• 제27권8호
• /
• pp.1033-1041
• /
• 2003

Two-phase flow pattern data during horizontal in-tube flow boiling are presented for pure and mixed refrigerants of R134a and Rl23, The flow pattern is observed through tubular sight glasses located at inlet and outlet of the test section, which is made of a stainless steel tube, 2m long with 10mm I.D., 1.5mm wall thickness. The obtained results are compared with the available various correlations for flow pattern. The flow pattern map of Hashizume was in good agreement with the present data except the region of low mass velocity. Weisman flow pattern map was also known to satisfactorily predict data for refrigerants in the region of annular flow. In this study, the flow pattern are simply classified into two groups; stratified(including intermittent, stratified and stratified-wavy) flow and annular flow. The transition quality from stratified to annular flow was obtained by modifying the liquid Froude number.

• Journal of the Optical Society of Korea
• /
• 제20권3호
• /
• pp.341-357
• /
• 2016

A novel asymmetric multiple-image encryption method using an octonion Fresnel transform (OFST) and a two-dimensional Sine Logistic modulation map (2D-SLMM) is presented. First, a new multiple-image information processing tool termed the octonion Fresneltransform is proposed, and then an efficient method to calculate the OFST of an octonion matrix is developed. Subsequently this tool is applied to process multiple plaintext images, which are represented by octonion algebra, holistically in a vector manner. The complex amplitude, formed from the components of the OFST-transformed original images and modulated by a random phase mask (RPM), is used to derive the ciphertext image by employing an amplitude- and phase-truncation approach in the Fresnel domain. To avoid sending whole RPMs to the receiver side for decryption, a random phase mask generation method based on SLMM, in which only the initial parameters of the chaotic function are needed to generate the RPMs, is designed. To enhance security, the ciphertext and two decryption keys produced in the encryption procedure are permuted by the proposed SLMM-based scrambling method. Numerical simulations have been carried out to demonstrate the proposed scheme's validity, high security, and high resistance to various attacks.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 추계학술대회논문집 II
• /
• pp.799-804
• /
• 2001

Nonlinear normal mode (NNM) vibration, in a nonlinear dual mass Hamiltonian system, which has 6th order homogeneous polynomial as a nonlinear term, is studied in this paper. The existence, bifurcation, and the orbital stability of periodic motions are to be studied in the phase space. In order to find the analytic expression of the invariant curves in the Poincare Map, which is a mapping of a phase trajectory onto 2 dimensional surface in 4 dimensional phase space, Whittaker's Adelphic Integral, instead of the direct integration of the equations of motion or the Birkhotf-Gustavson (B-G) canonical transformation, is derived for small value of energy. It is revealed that the integral of motion by Adelphic Integral is essentially consistent with the one obtained from the B-G transformation method. The resulting expression of the invariant curves can be used for analyzing the behavior of NNM vibration in the Poincare Map.

• 대한수학회보
• /
• 제53권4호
• /
• pp.985-1004
• /
• 2016

We consider the MAP/PH/c/K queue in which blocked customers retry to get service and servers may take vacations. The time interval between retrials and vacation times are of phase type (PH) distributions. Using the method of mean drift, a sufficient condition of ergodicity is provided. A condition for the system to be unstable is also given by the stochastic comparison method.

• 산업공학
• /
• 제25권4호
• /
• pp.393-404
• /
• 2012

Increasing safety requirements of automobile are asking companies to find out solutions, based on the ISO 26262 which is a functional safety standard. ISO 26262 is an adaptation of the IEC 61508 for automotive electric/electronic systems. ISO 26262 provides a V model for ECU (Electronic Control Unit) development process to secure safety against vehicle. It well describes the requirements, necessary works and their resulting products for each development phase. However, it is difficult to apply to product development for achieving functional safety in the electric/electronic systems of an automobile because it lacks explanation on the working steps to follow and the methodologies and tools to be used in each step. In this paper, we introduce the outline of the ISO 26262 product development process and present a DFSS (Design For Six Sigma) road-map based on the ISO 26262 product development process as a way to operate efficiently the ISO 26262 product development process. The DFSS road-map consists of five phases: Define, Measure, Analyze, Design, and Verify. The detailed activities, tools, inputs, and work products are given for each phase.