• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.24 no.9
• /
• pp.1157-1165
• /
• 2000

A classic examples of the abnormal combustions are the knock and misfire, which raise noxious performance and life of the engine. A heavy knock can also cause severe damages to the engine itself, which gives more reason why it must be detected and corrected. With the response of the today's requirements, we have researched the new diagnostic system which uses the breakdown voltage characteristics between electrodes of spark plug. This breakdown voltage depends on the pressure, temperature and even the shape and material of electrodes. But there is no data of breakdown voltage in case of using the spark plug as a electrodes. So, in this study, we show the breakdown voltage characteristic by pressure and temperature in constant volume bomb, which will make it possible to diagnose the engine combustion phenomenon.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2021.05a
• /
• pp.305-306
• /
• 2021

Breakdown structure (BS) is a tool used to allocate information packages for various management functions and drive computerized information systems. Although several BS exists, work breakdown structures (WBS) and cost breakdown structures (CBS) are the most widely studied and used in previous literature. Nevertheless, heterogeneity of BS and respective management capabilities in current practices are not adequately addressed. In this context, this paper compared the management capabilities of various BS in both building and plant industries through systematic literature. Management requirements and applications scope, in terms of life cycle and stakeholder, were analyzed, respectively. Finally, finding and lesson-learned are outlined.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.16 no.2
• /
• pp.151-156
• /
• 2003

High temperature superconductor can only be applied against an engineering specofication that has to be determined for each particular application form the design requirements for economic viability and for operation margins in service. However, in order to realize the HTS transformer, it is necessary to establish the high voltage insulation technique in cryogenic temperature. Therefore, the composite insulation of double pancake coil type transformer are described and AC breakdown voltage characteristics of liquid nitrogen(LN$_2$) under HTS pancake coil electrode made by Bi-2223/Ag are studied. The Breakdown of LN$_2$ is dominated electrode shape and distance. The influence of pressure on breakdown voltage is discussed with th different electrode. For the electrical insulation design of turn-to-turn insulation for the HTS transformer, we tested breakdown strength of insulation sheet under varying pressure. And we investigated surface flashover properties of LN$_2$ and complex conition of cryogenic gaseous nitrogen(CGN$_2$) obove a LN$_2$ surface. The surface voltage of GFRP was measured as a function of thickness and electrode distance in LN$_2$ and complex condition of CGN$_2$ above a LN$_2$ surface. this research presented information of electrical insulation design for double pancake coil(DPC) type HTS transformer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.08a
• /
• pp.52-57
• /
• 2002

High temperature superconductors can only be applied against an engineering specification that has to be determined for each particular application form the design requirements for economic viability and for operation margins in service. However, in order to realize the HTS transformer, it is necessary to establish the high voltage insulation technique in cryogenic temperature. Therefore, the composite insulation of double pancake coil type transformer are described and ac breakdown voltage characteristics of liquid nitrogen($LN_{2}$) under HITS pancake coil electrode made by Bi-2223/Ag are studied. Breakdown in $LN_{2}$ is dominated electrode shape and distance. And we investigated AC breakdown properties of $LN_{2}$ and complex conition of cryogenic gaseous nitrogen($CGN_{2}$) obove a $LN_{2}$ surface. Also, the surface voltage of GFRP was measured as a function of thickness and electrode distance in $LN_{2}$ and complex condition of $CGN_{2}$ above a $LN_{2}$ surface. This research presented information of electrical insulation design for double pancake coil type HTS transformer.

• Journal of the Korean Society of Systems Engineering
• /
• v.7 no.2
• /
• pp.31-37
• /
• 2011

Korean Naval Ship acquisition processes are very complicate. There are 4 phases, Feasibility Study, Concept Design, Basic Design, Detail Design and Construction. A number of organizations and support groups exist to acquire naval war ships. Thus, It is very important how to establish traceability about requirements. This work has investigated how to improve traceability about requirements using Shipboard Work Breakdown Structure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.30 no.4
• /
• pp.214-217
• /
• 2017

An IGBT (insulated gate bipolar transistor) device has an excellent current-conducting capability. It has been widely employed as a switching device to use in power supplies, converters, solar inverters, and household appliances or the like, designed to handle high power. The aim with IGBT is to meet the requirements for use in ideal power semiconductor devices with a high breakdown voltage, an on-state voltage drop, a high switching speed, and high reliability for power-device applications. In general, the concentration of the drift region decreases when the breakdown voltage increases, but the on-resistance and other characteristics should be reduced to improve the breakdown voltage and on-state voltage drop characteristics by optimizing the design and structure changes. In this paper, using the T-CAD, we designed the NPT-IGBT (non punch-through IGBT) and FS-IGBT (field stop IGBT) and analyzed the electrical characteristics of those devices. Our analysis of the electrical characteristics showed that the FS-IGBT was superior to the NPT-IGBT in terms of the on-state voltage drop.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.435-435
• /
• 2000

Light Rail Transit (LRT) system is a complex and large system in which there are many subsystems, interfaces, functions and demanding performance requirements. Because many contractors participate in the development, it is necessary to apply methods of sharing common objectives and communicating effectively among all of the stakeholders. This paper shows not only the methodology and the results of computer-aided systems engineering including requirement management, functional analysis and architecting LRT system, but also propose a tool to help manage a project by linking WBS (Work Breakdown Structure), work organization and PBS (Product Breakdown Structure). The application of computer-aided tool RDD-100 provides the capability to model product design knowledge and decisions about important issues such as architecting the top-level system. The product design knowledge will be essential in integrating the following life-cycle phase activities over the life of the LRT system. Additionally, when a new generation train system is required, the reuse of the database can increase the system design productivity and effectiveness significantly.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.17 no.1
• /
• pp.24-28
• /
• 2009

The reliability assessment is performed for Pressure Control Regulator of Aircraft Fuel System using reliability procedure which consists of the reliability analysis and the Failure Modes and Effects Analysis(FMEA). The target reliability as MTBF(Mean Time Between Failure) is set to 5000hr. During the reliability analysis process, the system is categorized by Work Breakdown Structure(WBS) up to level 3, and a reliability structure is defined by schematics of the system. Since the components and parts that have been collected through EPRD/NPRD. The predicted reliability to meet mission requirements and operating conditions is estimated as 4375.9hr. To accomplish the target reliability, the components and parts with high RPN have been identified and changed by analyzing the potential failure modes and effects. By changing the configuration design of components and parts with high-risk, the design is satisfied target reliability.

• Laser Solutions
• /
• v.11 no.2
• /
• pp.33-38
• /
• 2008

Laser micromachining has increasingly been adopted in various advanced industries where the high-precision machining of large-area, high-density and multi-layered components is in a strong demand. To effectively meet the requirements, the laser micromachining process must be carefully monitored. In order to facilitate the development of a new laser micromachining process and/or a new system, we have fabricated a UV laser micromachining platform that is equipped with optical modules for monitoring the process online. They include a laser power stabilizing module, a module for laser-induced breakdown spectroscopy, and an auto-focusing module.

• International conference on construction engineering and project management
• /
• 2015.10a
• /
• pp.716-717
• /
• 2015

A construction temporary work is main process and importance trade section. A technology system of construction temporary has very low availability of field works and needs improvements in Korea as construction site has a quick response about new requirements. This study reviews literature researches and can verify that changes to a comprehensive technology system for construction site. In addition, it suggests a breakdown structure of new standards for temporary construction technology based on views of construction site managers. Meanwhile, temporary construction technology in Korea has changed with a specification of construction temporary work which had been revised in 2014. However, the revision is merely dividing the design and building off of construction temporary technology. It is lacking in many ways to change this in a new standard system for temporary construction technology. Henceforth, it needs to develop a standard system for temporary construction technology and a professional system that is appropriate for different purposes by detail trade sections.