• 콘크리트학회논문집
• /
• 제16권2호
• /
• pp.229-240
• /
• 2004

불균형 휨모멘트를 재하받는 플랫플레이트-기둥 접합부의 편심전단강도와 모멘트강도를 규명하기 위해 그동안 많은 실험연구가 수행되어 왔다. 기존 실험들은 서로 다른 실험방식을 사용하고 있는데, 접합부의 전단강도는 실험방식에 따라 차이가 있는 것으로 나타났다. 따라서 기존 실험에 근거하여 개발된 현행 설계기준들은 플랫플레이트의 강도를 정확히 설명하고 있지 못한 실정이다. 선행 연구에서는 연속 플랫플레이트에 대한 비선형 유한요소해석에 근거하여, 슬래브-기둥 접합부에 패한 새로운 설계방법을 개발하였다. 그러나 제안된 설계방법에서는 휨모멘트 강도산정에 필요한 접합부 편심강도를 경험식에 의존하여 산정하고 있다. 본 연구에서는, 접합부 파괴 메카니즘을 분석하기 위해서, Rankine 재료파괴기준을 이용하는 이론적인 접근법을 채택하였다. 분석결과에 근거하여 개선된 편심전단강도모델이 개발되었고, 기존 실험과의 비교를 통해 검증되었다. 개발된 강도식을 이용하여, 선행연구에서 개발된 설계방법을 재검증하였다.

• Nuclear Engineering and Technology
• /
• 제55권10호
• /
• pp.3549-3558
• /
• 2023

The jet pump can be used in a test device of a nuclear reactor for high flow amplification as it reduces inlet flow requirement and thereby size of the process components. In the present work, a miniature jet pump was designed to meet high flow amplification greater than 3. Subsequently, experiments were carried out using a test setup for design validation and performance evaluation of the jet pump for different parameters. It was observed that a minimum pressure of 0.6 bar (g) was required for the secondary fluid inside the jet pump to ensure cavitation free performance at high amplification. Spacing between the nozzle tip and the mixing chamber entry point had significant effect on the performance of the jet pump. Variation in primary flow, temperature and area ratio also affected the performance. It was observed that at high flow amplification, the analytical solution differed significantly from experimental results due to very large velocities encountered in the miniature size jet pump.

• Journal of Information Technology Applications and Management
• /
• 제27권6호
• /
• pp.101-116
• /
• 2020

This study attempts to derive critical success factors and prioritize activities for implementing the automation of software test. Software testing proceeds in five steps of test plan, test case design, test scripting & test environment setup, test execution & evaluation, and test closure. From the literature, twenty influence factors in the five steps were identified. Focus Group Interviews with ten experts in software testing selected fourteen factors on the basis of importance and feasibility. Some factors were further divided to clarify their meanings and the number of influence factors finally became twenty one. A survey on the influence factors was conducted with 75 IT professionals. An importance-feasibility analysis was applied to the survey responses and classified the influence factors into four groups of essential factors, critical factors, low priority factors, and minimal factors. Essential factors include objectives for test automation, strategies for test automation, test automation training, test automation education, setting up test automation environment, setting up test environment, test automation tool selection. Critical factors include management's continued support, management's continued interest, role of automation engineers, and skills of automation engineers. This result suggests that a lot of efforts should be put into SW test plan for the successful SW test automation and SW automation should proceed in consideration with the priorities and resource consumption.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2003년도 추계학술대회논문집
• /
• pp.638-642
• /
• 2003

This paper presents a parameter design of an Electrorheological(ER) panel for noise reduction using Taguchi method. Taguchi method is a robust design method that determines control parameters in the presence of noise effect. Host structure thickness, spacer thickness, base oil viscosity and the weight ratio of ER particles are chosen for the control factors. A test setup in an SAE J1400 facility is used to analyze the sound transmission loss. The sensitivity of each factor with signal-to-noise(S/N) ratio and analysis of variance are investigated. The analysis results show that the weight ratio of ER particle and base oil viscosity of the ER fluid mostly affects the noise reduction in the presence of electric field. Based on the Taguchi method, an optimal configuration was designed and comparison is made with experimental result fer the verification.

• 한국초전도ㆍ저온공학회논문지
• /
• 제13권3호
• /
• pp.1-4
• /
• 2011

This paper deals with the design and fabrication of prototype superconducting hybrid electromagnet(SH-EM) for EMS (Electromagnetic suspension)-based Maglev. The design requirements are based on the normal conducting EM used in the German high-speed Maglev. From the MMF-Levitation force curves simulated by FEM analysis, the required MMF by superconducting coil is suggested. As an experimental test setup to demonstrate the SH-EM, the experimental SH-EM with HTS coil cooled in $LN_2$ is fabricated. From the expected operating current of the HTS coil, the levitation performance of the SH-EM is estimated.

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 2002년도 춘계공동학술대회
• /
• pp.390-396
• /
• 2002

This study is concerned with the strict machine-cell and part-family grouping (MCPFG) in cellular manufacturing system design. Most of MCPFG methodologies often suffer from improper assignment of machines and parts in which exceptional machine has more common operations with machines in a cell other than its own cell and exceptional part has more operations through machines in a cell other than the cell corresponding to its own family. This results in the loss of similarity in part design or common setup of machines and the benefits from the conversion of job shop manufacturing into cellular manufacturing are lost. In this study, a two-phase methodology is proposed to find the machine-cells and part families under the strict constraints in which all machines and parts are assigned to its most proper cells and families. Test results with moderately medium-sized ill-structured MCPFG problems available from the literature show the substantial efficiency of the proposed approach.

• 융합보안논문지
• /
• 제2권2호
• /
• pp.199-207
• /
• 2002

최근에 들어와서는 컴퓨터 바이러스와 해킹에 대한 공격이 심각한 수준에 와 있다. 이제 컴퓨터 바이러스는 특정 사건이 아니라 우리의 생활 속에서 발생할 수 있는 실질적인 피해임을 느낄 수 있다. 특히 1999년 이후에 나타난 바이러스는 다양한 변화를 보였고, 진보된 형태의 바이러스도 많이 나타났다. 일부 바이러스는 자신의 코드를 재배치하는 암호화 기술을 사용하기도 한다. 이에 따라서 백신 프로그램들은 바이러스의 암호화를 다시 복호화 하기 위해 가상 실행 엔진(emulation mine)을 사용하고 있다. 이러한 바이러스의 복잡한 암호화 기술 및 복호화 기술은 O.S의 종류에 따라 형식이 다양하다. 따라서 하나의 시스템에서 여러 가지 운영체제의 가상 실행 엔진을 사용하기 위해서 다수의 운영체제를 같이 사용할 수 있게 해주는 응용 소프트웨어인 VMware를 사용하여 '바이러스 Test Simulation'의 설계 및 구현을 할 수 있다.

• International Journal of Concrete Structures and Materials
• /
• 제11권2호
• /
• pp.343-363
• /
• 2017

The objective of this work was finding out the most advisable testing conditions for an effective and robust characterization of the tensile strength (TS) of concrete disks. The independent variables were the loading geometry, the angle subtended by the contact area, disk diameter and thickness, maximum aggregate size, and the sample compression strength (CS). The effect of the independent variables was studied in a three groups of experiments using a factorial design with two levels and four factors. The likeliest location where failure beginning was calculated using the equations that account for the stress-strain field developed within the disk. The theoretical outcome shows that for failure beginning at the geometric center of the sample, it is necessary for the contact angle in the loading setup to be larger than or equal to a threshold value. Nevertheless, the measured indirect tensile strength must be adjusted to get a close estimate of the uniaxial TS of the material. The correction depends on the loading geometry, and we got their mathematical expression and cross-validated them with the reported in the literature. The experimental results show that a loading geometry with a curved contact area, uniform load distribution over the contact area, loads projected parallel to one another within the disk, and a contact angle bigger of $12^{\circ}$ is the most advisable and robust setup for implementation of BT on concrete disks. This work provides a description of the BT carries on concrete disks and put forward a characterization technique to study costly samples of cement based material that have been enabled to display new and improved properties with nanomaterials.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
• /
• pp.2787-2794
• /
• 2011

A mesh node, a component of a mesh network, is connected with the network by dynamic routing using routing protocol and collects the information of adjacent or connected mesh nodes for its self-management and settings. Also, it relays packets between the mesh nodes and provides AP(Access Point) with its corresponding functions based on IEEE 802.11 a/b/g for clients' access to the network. In this paper, the study focused on the design and performance tests of Wireless Mesh Network(WMN) which is applied to the wireless communication network for the CBTC(Communications Based Train Control) system. The WMN was established on a K-AGT test-line (Kyeongsan city, Gyeongsangbuk-do), and to verify the applicability, its operation and performances are checked by measuring the data throughput, delay latency, quality measurements such as transmission loss, radio interference and path recovery and setup between the on-board and wayside.

• 한국압력기기공학회 논문집
• /
• 제6권1호
• /
• pp.57-64
• /
• 2010

PHE(Process Heat Exchanger) is a key component required to transfer heat energy of $950^{\circ}C$ generated in a VHTR(Very High Temperature Reactor) to the chemical reaction that yields a large quantity of hydrogen. Korea Atomic Energy Research Institute established the gas loop for the performance test of components, which are used in the VHTR, and they manufactured a PHE prototype to be tested in the loop. In this study, as part of the high-temperature structural-integrity evaluation of the PHE prototype, which is scheduled to be tested in the gas loop, we carried out high-temperature structural-analysis modeling, thermal analysis, and thermal expansion analysis of the PHE prototype. The results obtained in this study will be used to design the performance test setup for the PHE prototype.