• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.199-202
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• 2008

The advantage of ultrasonic burning rate measurement of solid propellant is measuring burning rates with wide range of pressure in a single test. In the ultrasonic method, instantaneous thickness of solid propellants as function of pressure or time were measured using time of flight(TOF) of ultrasonic signals. So, uncertainties of the measured burning rates by ultrasonic method have to evaluate with variation of pressure, TOF and initial propellant thickness. In this study, we evaluated uncertainties of ultrasonic method for measuring burning rates on the types 317 and the 318 propellants.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.161-164
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• 2008

It is played an important part in dam safety that KWATER is taken the responsibility of design, construction and maintenance about dam. It is considered that safety inspection of accumulated technology and knowledge of new evaluation method have developed. Thus this study is that instrumentation data is analyzed continually and dam's safety is evaluated about behavior property, in Chungju concrete dam. New evaluation method is that instrumentation data is analyzed reliability. It is suggested that suitability of management period and maintenance of instrument in dams.

• Journal of Labour Economics
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• v.32 no.3
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• pp.27-59
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• 2009

Using Korea Education Longitudinal Study and administrative school data, this paper analyzes school characteristics that influence the demand for private education. Among other findings, it should be noted that private education expenditure tends to be decreased when student evaluation of teacher effectiveness is high, the average education level of teachers is high, and individualized education is offered through subject-based classroom. These results suggest that the demand for private education could be dropped by a better quality and high effort of teachers, which would be attained through an improved education system for teaching profession and student-oriented teacher evaluation. In addition, ability grouping within school via subject-based classrooms with different levels appears to be helpful to overcome uniformity of school equalization system without inducing an increasing demand for private education.

• Journal of Engineering Education Research
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• v.7 no.1
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• pp.51-63
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• 2004

The accreditation system for engineering technology programs has not been carried out in this country. For need of accreditation for engineering technology programs and development of evaluation criteria, we need analyses of accreditation procedures, rules and evaluation criteria. So we researched accreditation system and evaluation criteria with countries. These are signatories to the Sydney Accord under which approved engineering technology programs. Accreditation procedures and evaluation criteria are characteristic of the each countries which carried out accreditation system. We have to introduce accreditation system and develop evaluation criteria in our manner for advancing our engineering technology education of community college.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.9
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• pp.781-788
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• 2012

Flow in the oxidizer manifold of a liquid rocket combustor has been analysed using an open source CFD toolbox, OpenFOAM. The applicability of OpenFOAM to the problems with complex geometries involving porous media zones for simulating the pressure drop induced by the injectors has been evaluated by performing turbulent, incompressible steady-state flow analysis. The usefulness and applicable area of the OpenFOAM as a design evaluation and analysis tool will be confirmed and enlarged by further evaluation with various computational cases representing major physical phenomena in rocket combustion devices.

• The Korean Journal of Archival Studies
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• no.63
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• pp.115-144
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• 2020

This paper aims to provide a reference case for the reform of the Korean records management system through the operation of the interim preservation facility of the Kanagawa Prefectural Archives in Japan, and the early transfer system, appraisal and selection system of current records.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.148-153
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• 2017

During natural ageing of HTPB propellant undergoes a series of slow physico-chemical degradation reactions. By using accelerated ageing conditions it is possible to simulate the material behaviour at different time-temperature conditions especially focused on the in-service conditions. Ageing behaviour of HTPB propellant were investigated using HFC(Micro-Heat Flow Calorimeter) is universal technique for measuring the rate of slow chemical and physical processes in long-term storage.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.5
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• pp.59-65
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• 2018

During natural aging, hydroxyl-terminated polybutadiene(HTPB) propellant undergoes a series of slow physico-chemical degradation reactions. By using accelerated ageing conditions it is possible to simulate the material behavior at different time-temperatures focusing on in-service conditions. Aging behaviors of HTPB propellant are investigated using HFC(heat flow calorimeter), a universal technique for measuring the rate of slow chemical and physical processes in long-term storage.

• Smart Media Journal
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• v.11 no.7
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• pp.70-75
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• 2022

In 2019, the government improved the system to reduce the maximum weight of economic feasibility items in the comprehensive evaluation from 50% to 45% in order to improve the problem that economic feasibility is a decisive factor in passing the preliminary feasibility study. This study is to analyze the effect of system improvement in 2019 and verified the difference between before and after system improvement. As a result of regression analysis and correlation analysis, both periods showed high correlation, and the difference through Z-test was analyzed as not statistically significant. This result means that institutional improvement to reduce the impact of economics was not effective. Therefore, it is judged that it is necessary to discuss the design of a more effective comprehensive evaluation study through research such as reevaluating the weights of each item in the comprehensive evaluation in various ways in existing projects.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.10a
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• pp.218-220
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• 2010

우리나라 연안 해역은 빈번한 선박조우로 인하여 해양사고 발생 잠재 위험이 높은 해역으로 분류되고 있으나 해상교통의 정량적인 평가의 미흡으로 맞춤형 안전대책이 제대로 수립되고 있지 않는 것이 현실이다. 본 연구에서는 해상교통 안전성 평가모델 중 하나인 IWRAP(IALA Waterway Risk Assessment Program)에 대한 기본적인 소개와 함께, 울산항을 대상으로 한 평가 사례 소개, 기존 유사한 연구와의 비교를 하고자 한다.