• Journal of KIISE:Computing Practices and Letters
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• v.10 no.5
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• pp.385-393
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• 2004

Cluster systems have been widely used for solving problems in various application domains, and regarded as useful high performance computing resources. As the number of cluster system user is increasing, it is no less important to maintain stable operation than to improve cluster system performance. Although hardware preventive maintenance is important for keeping normal operation, the testing tool which can be used for general cluster systems during maintenance has received little attention. In this Paper, considering hardware Preventive maintenance, we suggest a testing tool for hardware of cluster system. The cluster system testing tool which is named CTS(Cluster system Test Suite) has two check routines; one for memory, and the other for NIC respectively. The CTS is designed to support the common features of general cluster systems and all the Jobs such as setting test conditions to querying the results can be done entirely within an integrated GUI environment. CTS is used as the testing tool for two kinds of cluster systems during maintenance, and the experimental results show that CTS reports useful information for cluster systems management.

• Advances in pediatric surgery
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• v.12 no.2
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• pp.202-212
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• 2006

The prognostic factors for extrahepatic biliary atresia (EHBA) after Kasai portoenterostomy include the patient's age at portoenterostomy (age), size of bile duct in theporta hepatis (size), clearance of jaundice after operation (clearance) and the surgeon's experience. The aim of this study is to examine the most significant prognostic factor of EHBA after Kasai portoenterostomy. This retrospective study was done in 51 cases of EHBA that received Kasai portoenterostomy by one pediatric surgeon. For the statistical analysis, Kaplan-Meier method, Logrank test and Cox regression test were used. A p value of less than 0.05 was considered to be significant. Fifteen patients were regarded as dead in this study, including nine cases of liver transplantation. There was no significant difference of survival to age. The age is also not a significant risk factor for survival in this study (Cox Regression test; p = 0.63). There was no significant difference in survival in relation to the size of bile duct. However, bile duct size was a significant risk factor for survival (Cox Regression test; p = 0.002). There was a significant difference in relation to survival and clearance (Kaplan-Meier method; p = 0.02). The clearing was also a significant risk factor for survival (Cox Regression test; p = 0.001). The clearance of jaundice is the most significant prognostic factor of EHBA after Kasai portoenterostomy.

• The Transactions of the Korea Information Processing Society
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• v.3 no.2
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• pp.339-347
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• 1996

object-oriented programming is used to develop next-generation telecommu- nications services running on the distributed processing environment. In order to test these services efficiently at the system-level during not only in the development phase but also in the operation phase, we define an embedded monitor service within the infrastructure to monitor the operation of the distributed programs, and describe a system-level test mechanism based on the monitor service. By separating the function of monitor server which monitors operations of objects and collects monitored data and that of tester which makes analysis and decides the sequence of test events, the invasive effect of monitoring can be minimized. At the same time, accurate diagnosis on the system can be achieve by exploiting the test mechanism. The mechanism, as a core component for the implementation of real-time fault-tol-erant systems, is applicable to general-purpose distributeded systems as well.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.141-144
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• 2015

The superconducting fault current limiter (SFCL) is an electric power device that limits the fault current immediately in a power grid. Korea Electric Power Corporation (KEPCO) has been developing a 154 kV, 2 kA SFCL since 2011 to protect power grids from increasing fault current and improve the stability and quality of electric power. This SFCL adopts 2G YBCO wires and operates at 71 K and 5 bars. In this paper, a cooling system for the 154 kV SFCL and its cooling test results are reported. This cooling system uses a Stirling-type cooler to make sub-cooled liquid nitrogen ($LN_2$), which cools the superconductor modules of the SFCL. The $LN_2$ is circulated between the cooler and the cryostat that contains superconductor modules. The $LN_2$ also plays the role of a high voltage insulator between the modules and the cryostat, so the pressure was maintained at 5 bars for high insulation performance. After installation in a test site, the cooling characteristics of the system were tested. In this operation test, some important data were measured such as temperature distribution in $LN_2$, pressure change, performance of the heat exchanger, and cooling capacity of the total system. Consequently, the results indicate that the cooling system operates well as designed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.338-344
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• 2021

In this study, an actual test procedure was considered for the effective operation of a bulletproof test. The problems of the existing system were drawn in two ways. First, it is difficult to mount items of various shapes. Second, various test standards cannot be applied. To improve these problems, an automated and standardized mounting system was designed/applied to mount various items. The multi-purpose mount was compatible with the backing support for body armor testing. The sample holding frame was located inside and was designed to mount samples of various sizes and shapes through vertical movement and fixation without a separate detachment/attachment process. A comparison of the economics before and after the introduction of the item mounting system confirmed the effectiveness of the system by the increased number of daily tests and equipment utilization and reduced hourly cost.

• Journal of Korean Institute of Industrial Engineers
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• v.38 no.4
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• pp.262-275
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• 2012

This paper develops a multistage scheduling algorithm for the module operation of the LCD(Liquid Crystal Display) production systems and tests the efficiency of the proposed algorithm. The module operation is a multistage form composed of multiple sub operations of processes, and each stage is consists of multiple lines with the same kinds of machines. This paper presents a mathematical modeling reflecting the constraints of the LCD module operation and develops a multistage scheduling algorithm based on tabu search metaheuristic approach. For this purpose, an production order is assigned to a line of the sub operations and a sequence of the assigned order is rearranged to draw an efficient schedule. Simulation experiments test performance measures and show the efficiency of the proposed algorithm.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.322-322
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• 2016

Phase change memory (PCM) has attracted much attention as one of the most promising candidates for next-generation nonvolatile memory. In that regard, the purposes of the study are to propose reference of effective pulse parameter to control phase switching operation and to invest the effect of nitrogen doped in PCM materials for improved cycling stability and economic energy consumption. Switching operation of PCM is affected by electric pulse parameter and as shown in figure.1 are composed to RT(rising time), ST(setting time), FT(falling time) and the effect of these parameter was precisely investigated. Transmission electron microscope (TEM) was used to confirm fine structure and retention cycle test was conducted to confirm reliability. Finally improvement reliability and economic power consumption in quantitatively are obtainable by optimum pulse parameter and nitrogen doping in GST material. these study is related to the engineering background of other semiconductor industries and it have confirmed to possibility further applications.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.4
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• pp.62-68
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• 2015

Subsynchronous Resonance is a condition where the electrical power systems composed of generator and transmission line exchange energy with mechanical turbine-generator system at the frequency of the combined below the subsynchronous frequency. Therefore, the frequency of power systems should be associated with the subsynchronous resonance. This paper describes subsynchronous resonance by flexible frequency operation. It focuses on the characteristics and behavior of subsynchronous resonance. The subsynchronous resonance is being conducted by real-time digital simulator and the IEEE benchmark model for subsynchronous resonance have been utilized for the test systems.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.12
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• pp.979-986
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• 2003

The performance characteristics of heating and cooling operation for a heat pump system using seawater heat source and exhaust energy are presented. The heat pump system is made of a waste heat recovery system and a vapor compression refrigeration system. The working fluid is R-22. The heat pump system COPs are measured during heating and cooling operation modes, and the resultant COPs were 9.7 and 7.9, respectively, which are three times higher than those of the heat pump itself. Therefore, the performance of the heat pump system using exhaust energy is excellent compared to that of a general heat pump. The experimental data can be effectively used for the design of the high efficient heat pump using a seawater heat source.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2000.11a
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• pp.91-96
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• 2000

A commercial-scale Fluidized Bed Incinerator(FBI) to treat dewatered sludges has been developed by Jindo Corporation, Korea, as one of the governmental R&D project during 1990 to 1997. The FBI plant was constructed at Kunsan city and fully in operation after finishing the successful test-burn period since June 1998. The company now has a capability of the design, construction and operation of commercial FBI plants. This paper introduces the experiences of design and operation of Kunsan FBI plant, which has the capacity of 60 ton/day and incinerates various sludges from waste water treatment facilities and liquid waste such as waste oil or waste solvent.