• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.4
• /
• pp.33-41
• /
• 2015

With rapid rise of virtualization technology from diverse types of cloud computing service, security problems such as data safety and reliability are the issues at stake. Since damage in virtualization layer of cloud service can cause damage on all host (user) tasks, Hypervisor that provides an environment for multiple virtual operating systems can be a target of attackers. This paper propose a security structure for protecting Hypervisor from hacking and malware infection.

• Journal of Information Technology Services
• /
• v.19 no.3
• /
• pp.151-163
• /
• 2020

This paper describes a study on the FRACAS(Failure Reporting Analysis and Corrective Action System)-based dependability control platform for domestic urban railway trains. There are more demands for the verification of the dependability of trains as it becomes a regulation for train manufacturers to verify the dependability recently. Train manufacturers as well as railway operators need a effective FRACAS solution to perform the verification of the dependability. Yet current FRACAS solutions have limitations to support the verification processes effectively. This paper addresses the issues of current FRACAS solutions and suggests a FRACAS framework designed for the domestic urban railway trains. Service failure scenarios are standardized using the proposed availability model to implement a more user-friendly and reliable platform. A new FRACAS-based platform for the dependability control (SCARF^®) has been developed to implement the suggested framework. The detail interfaces and functions of the platform are explained. The SCARF^® platform is expected to engage the increasing demands for the dependability control successfully enhancing the reliability, maintainability, availability and safety of domestic urban railway trains eventually.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.29 no.11
• /
• pp.729-735
• /
• 2016

It is highly important issue to use an energy efficiently for sustainable prosperity of mankind. From this point of view, using LED lighting can be a good alternative because it has a lot of advantages such as high efficiency, long life time and eco-friendly manufacturing process. That is the reason why using LED lighting has been encouraged worldwide. However, in situations that LED lighting is replacing traditional lighting quickly, the problem of the flicker of LED lighting has emerged as an important issue. Therefore, in foreign countries like US or Japan in order to ensure the reliability of LED lighting, study for flickering effects of the human body and test methods are have been actively conducted. But related research in domestic situation is an insufficient condition. In this study, a flicker characteristic was measured conventional lamps such as incandescent lamps or fluorescent lamp and 81 items of LED lightings which are distributed in domestic markets.

• The KSFM Journal of Fluid Machinery
• /
• v.4 no.4 s.13
• /
• pp.16-21
• /
• 2001

The field tests on the waterhammer were carried out for PalDang intake pumping station of the metropolitan water supply 5th stage project. The pumping station was equipped with the pump control valve as the main surge suppression device and the surge relief valve as auxiliary. However, the pump control valve had not been early controlled in the planned closing mode, and the slamming occurred to the valve which abruptly closed during the large reverse flow. Because the pressure wave caused by the pump failure was superposed on the slam surge, the upsurge increased so extremely that the shaft of the valve was damaged. It was desirable that the surge relief valve was installed in the pumping station or near the pump exit for the delay of response. After reforming the oil dashpot of the pump control valve, the sliming disappeared and the measured pressure was in fairly good agreement with the results of simulation. In case of three pumps for ${\phi}2,600$ pipeline being simultaneously tripped, the pressure head in the pumping station increased to 95.6 m, and the upsurge caused by the emergency stop of four pumps for ${\phi}2,800$ pipeline was 89.6m. We concluded that the pumping station acquired the safety and reliability for the pressure surge.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.11a
• /
• pp.191-196
• /
• 1996

The potential value of the Application Specific Integrated Circuits(ASIC's) in safety systems of Nuclear Power Plants(NPP's) is being increasingly recognized because they are essentially hardwired circuitry on a chip, the reliability of the system can be proved more easily than that of software based systems which is difficult in point of software V&V(Verification and Validation). There are two types of ASIC, one is a full customized type, the other is a half customized type. PLD(Programmable Logic Device) used in this paper is a half customized ASIC which is a device consisting of blocks of logic connected with programmable interconnections that are customized in the package by end users. This paper describes the RPS(Reactor Protection System) composed of ASICs which provides emergency shutdown of the reactor to protect the core and the pressure boundary of RCS(Reactor Coolant System) in NPP's. The RPS is largely composed of five logic blocks, each of them was implemented in one PLD, as the followings. A). Bistable Logic B). Matrix Logic C).Initiation Logic D). MMI(Man Machine Interface) Logic E). Test Logic.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.33 no.8
• /
• pp.739-744
• /
• 2009

Rail-pad is an important and readily replaceable component of a railway track, as it is the elastic layer between the rail and the sleeper. Characteristics and useful lifetime prediction of rail-pad was very important in design procedure to assure the safety and reliability. In this paper, the degradation of rail pad properties as a function of their in-service life is studied with a view of developing a technique for predicting the optimum period of track maintenance with regard to pad replacement. In order to investigate the useful lifetime, the accelerate test were carried out. Accelerated test results changes as the threshold are used for assessment of the useful life and time to threshold value were plotted against reciprocal of absolute temperature to give the Arrhenius plot. By using the acceleration test, several useful lifetime prediction for rail-pads were proposed.

• Journal of Navigation and Port Research
• /
• v.35 no.8
• /
• pp.649-656
• /
• 2011

Marina industry is growing as a higher value-added business. This study aims to develop a tool that measures marina service quality from marina users' perspective. As the result of empirical analysis, five of marina service quality aspects including physical facilities, support services, activity programs, employees' attitude, and safety were drawn. In addition, 20 measurement items whose reliability and validity were verified were suggested. The scale developed by this study is not only an important tool to measure marina service quality but also contributes to marina service quality control, and seem, to provide useful information for establishing marketing strategies.

• Transactions of Materials Processing
• /
• v.21 no.5
• /
• pp.305-311
• /
• 2012

One of the main methods of building LNG tankers uses the Moss spherical tank design since it can be precisely analyzed with respect to reliability and safety of construction by stress analysis. Aluminum alloy 5083 is generally used in the Moss spherical tank design for the wall in constructing the LNG tanker. This aluminum alloy does not have low temperature brittleness, but has good corrosion resistance, good weldability, and excellent material properties for the application. The Moss spherical tank is constructed with several sections of A5083 thick plate with curved surfaces, which are welded together. It is essential to predict the amount of springback for the deformed thick plates in design to insure a reliable construction because the structure needs to be assembled into a perfect sphere. Unless the initial construction meets the design, there are additional processing costs for reworking to meet the specifications as well as a cost penalty paid to a consumer. In this paper, FE analyses were conducted to predict the amount of springback for various forming conditions and forming processes. The various forming processes were evaluated with respect to reducing springback and compared with the conventional forming process used for curved surfaces of thick Al plate.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.21 no.6
• /
• pp.920-925
• /
• 2012

A study of vehicle weight lightening has been progressed to reduce the fuel consumption. In this paper, the body floor in an EV (Electric Vehicle) bus has been applied by composites as CFRP and GFRP. In order to analyse a various reliability and safety, an experiment and FEM analysis was carried out to obtain weight lightening. Especially, the joint. An effective design is obtained through an experiment as well as FEM analysis. Results of stress analysis of GFRP material showed twice as much displacement than those of CFRP material. Among three kinds of joint methods, the bond joint method is occurred to a substantial shape change in the body and floor. It is found that the rivet joints are fairly suitable for stress sustaining capability.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2003.11a
• /
• pp.707-719
• /
• 2003

The D&D work requires worker's safety and high reliability of operation because it has been processing in high radioactive environment. Therefore, it is necessary to select the dismantling items and applicable dismantling technologies and analyze the scenarios for selected items. In this paper, the main dismantling items were selected by the consideration of several factors, their 3D CAD models were constructed as well. The applicable dismantling technologies for each dismantling items were selected and their dismantling scenarios were setup. Finally the 3D graphic simulations for the shielding concrete, the RSR, and the core are performed.