• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.5
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• pp.51-59
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• 2016

STS 321 stainless steel is generally used for a material of high-temperature and high-pressure system including liquid rocket engine. The constitutive equation for flow stress has been suggested using thermal stress component and athermal stress component based on Kocks dislocation barrier model to predict 321 stainless steel's deformation behavior at elevated temperature. The suggested model predicted well the material deformation behaviors of 321 stainless steel at the wide temperature range from room temperature to $500^{\circ}C$.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.6
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• pp.87-94
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• 2019

This paper contains the process of investigating the cause of fuel filter contamination of P&WC's PT6A-67A engine. An outline of the fuel filter contamination and configuration of the fuel supply line are specified. The analytical methods were classified into fuel component analysis and solid sediment analysis(EDX, TGA, optical microscope). In summary, the sulfur was detected from fuel tank sealant as a major contamination component. As a follow-up, P&WC and the Agency for Defense Development will conduct engine fuel filter cycle checks and fuel tank cleaning for engine operation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.4
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• pp.332-339
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• 2004

A technical analysis was conducted to predict the development trend for the highly efficient absorption type refrigeration system. The study was based on a submitted patent during January 1981 and December 2000 in Korea, Japan and America. The total number of extruded patents from the registered database was 24,822 and the filtering process makes the reduction of the data number to 3,510. Technical development of Japan for the absorption type refrigeration system is prominent compared to the other country due to approximately 75％ of the patents coming from Japan. When the patent is divided into two categories, the patent for component technology for the refrigeration system makes up 75％ and the refrigerating type technology 25％ of the patents. This shows technical development for the system component is advanced compared to the technology development for the system type. When the patents are classified by nationality of patent applicants, foreigners contribute up to 33％ of the patents in Korea. However, Japan's case shows the 99％ of the patents are invented by the Japanese. If the patents are classified to the International Patent Classification, most of the data for the absorption type refrigeration system belongs to IPC F25B.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.188-191
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• 2007

This paper shows the Development of In-tank pressure regulator and Solenoid Valve used in FCV(Fuel Cell Vehicle). We have developed new type of Regulator and Solenoid through analysis of the structure and characteristics of component of FCS(Fuel Cell System) from the advanced technology. Now it is possible to localize the component by making use of the development of Regulator and Solenoid made by us. Regulator and Solenoid is a equipment to control hydrogen pressure supplied into a stack. Therefore, outlet pressure, a flow of fluid and temperature are important parameters according to a inlet pressure. And leak test, endurance test and burst test should be done to guarantee the performance and safety of Regulator and Solenoid used in the fuel of high pressure. Also, Hydrogen friendly materials are applied to inner parts of the Regulator, Solenoid and weight reduction is done to cost saving in part not related to performance. As a result, we have proven the good performance and reliability in endurance of Regulator, Solenoid and will make an development in performance as well as durability to ensure industrialization.

• The KIPS Transactions:PartD
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• v.9D no.4
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• pp.703-712
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• 2002

Since component-based development technologies support reusability and enhance productivity of application development, they are adopted for rapid and efficient software development, and among them, EJB component is a Jana-based software development technology widely used in industry. In this paper, we designed and implemented bulletin board and shopping mall which are major constituents of mobile e-commerce system using EJB components, and suggest construction guideline supporting reusability and interoperability.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.2
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• pp.159-166
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• 2014

The study is conducted on the subject of optimization of components sizing for series hybrid electric propulsion systems. The components sizing of series type hybrid system is very important because each component of series type is larger than the corresponding component of the parallel type or series-parallel type. If the components sizing is greater or less than what is required to this system, the performance of the system is getting worse. The methodology for the sizing of a driving motor is introduced based on the foundation of determined system configuration and performance target. And the sizing of an engine/generator and a battery is achieved based on simulation results using Dynamic Programming. It is possible to find the optimal sizing of these components by comparing fuel efficiency of hybrid electric propulsion system for 8 driving cycles.

• Journal of the Korean Society of Systems Engineering
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• v.17 no.1
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• pp.21-34
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• 2021

The use of Field-Programmable Gate Arrays (FPGAs) in the development of safety-related Human-Machine Interface (HMI) systems has gained much momentum in nuclear applications. Recently, one of the application areas for the Advanced Power Reactor 1400 (APR1400) is in the development of the advanced Component Interface Module (CIM) of the Engineered Safety Features Actuation System (ESFAS). Using systems engineering approach, we have developed a new FPGA-based advanced CIM software. The first step of our software development process involves the Preliminary Hazard Analysis (PHA) based on the previous CIM design. In this paper, we describe the qualitative approach used in performing the preliminary hazard analysis. The paper presents the methodology for applying a modified Hazard and Operability (HAZOP) procedure for the conduct of PHA which resulted in a qualitative risk-ranking scheme that informed the decisions for the safety criteria in the requirements specification phase. The qualitative approach provided the justification for design changes during the advanced CIM software development process.

• International Journal of Computer Science & Network Security
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• v.22 no.10
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• pp.91-96
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• 2022

Article materials reflect the results of scientific research and generalization of experience concerning quality measurement of student's educational activities in the context of innovative development of the educational process, which is ensured by introducing educational innovations. The main point of monitoring of higher education students' activities and also phenomenon of education quality, particularly its results, are determined in the research. Guided by the scientific theory and personal experience of scientific and pedagogical activities, the attempt to single out the key components, important indicators and to introduce component indicator model of quality of higher education students' activities on the qualimetry base has been performed. Methodical solutions concerning the application of the developed model to determine the dynamics of pedagogical students' educational achievements by particular educational components in the process of innovative development of educational process are proposed. The advanced studies that relate to the development of methods for monitoring the quality of pedagogical higher education students' activities on the basis of systemic, competence and qualimetry approaches taking into account the levels of education and chosen specialties have been decided.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.4
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• pp.207-214
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• 2022

A prediction model is proposed for a blast load acting on a column component because of an external explosion. The model can predict the pressure-time histories acting on a column using the fitting curves established from a database composed of finite-element (FE) analysis results. To this end, 70 numerical simulations using the commercial software AUTODYN were performed by changing the column width. To confirm the performance of the proposed model, pressure-time histories estimated from an existing empirical formula and the proposed model were compared based on the FE analysis results. It was verified that the proposed model can more precisely predict the pressure-time histories compared with the existing model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.297-302
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• 2007

Vibrating test of vehicle component can be possible in lab-based simulators instead of field testing owing to the development of technology in control algorithm as well as computational process. Currently, Multi-Axial Simulation Table(MAST) is recommended as a vibrating equipment, which excites a target component for 3-directional translation and rotation motion simultaneously and hence, vibrational condition can be fully approximated to that of real road test. But, the vibration-free performance of target component is not guaranteed with MAST system, which is only simulator subjective to the operator. Rather, the reliability of multi-axial vibration test is dependent on the quality of input profile which should cover the required severity of vibrating condition on target component. In this paper, multi-axial vibration testing methodology of vehicle component is presented here, from data acquisition of vehicle accelerations to the obtaining the input profile of MAST using severe data at proving ground. To compare the severity of vibration condition, between real road test and proving ground one, energy principle of equivalent damage is proposed to calculate energy matrices of acceleration data and then, it is determined the optimal combination of special events on proving ground which is equivalent to real road test at the aspects of vibration fatigue using sequential searching optimal algorithm. To explain the vibration methodology clearly, seat and door component of vehicle are selected as a example.