• The Journal of Engineering Geology
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• v.15 no.3
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• pp.309-323
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• 2005

Dynamic stiffness of subsurface materials is one of the most important geotechnical parameters in predicting deformational behavior of structures as well as practicing seismic design and performance evaluation. In an effort to measure the parameter efficiently and accurately, various borehole seismic testing techniques have been, thus, developed and used during past several decades. Moreover, recent rush of underground-space projects and increasing size of structures put more stress on reliable site investigation techniques in estimating stiffness of rock mass. In this paper, a new technique called 'in-hole seismic test' has been implemented to measure the dynamic stiffness of rock masses at subsurface foundations and tunnel-faces. The reliance of in-hole seismic test was evaluated by comparing the testing results at several rock sites with those of other borehole techniques and the technique tunnls out to be an efficient and accurate in-situ testing technique.

• Journal of Korean Society of Steel Construction
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• v.20 no.2
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• pp.247-258
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• 2008

In this study, static loading tests were performed on H-beam specimens to assess the static behavior of H-beam prestressed with multi-stepwise thermal prestressing method (TPSM). The amount of induced thermal prestress and connection type were differentiated among the 400-mm-high and 6,000-mm-long H-beam specimens to evaluate their effect on the behavior of the beams. From the experimental results, it between the H-beam and the cover-plate increased in yielding load by 13~18%, whereas stiffness increased by 27~34%. In case of specimens with both bolting and welding connection, yie lding load increased by 18~29% and stiffness increased by 43~51%. Multi-stepwise initial stress distribution was also observed from the prestressed specimens, verifying the effectiveness of the multi-stepwise TPSM. By application of the multi-stepwise TPSM, a significant increase in yielding load and stiffness can be achieved, hence increasing sectional and prestressing efficiencies.

• Journal of Soil and Groundwater Environment
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• v.10 no.2
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• pp.59-65
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• 2005

Step-drawdown test has been generally conducted to evaluate productivity or efficiency of both aquifer and well. In general step-drawdown test, pumping with a low constant discharge rate is conducted in the first stage until the drawdown within the well stabilizes. And then the groundwater is pumped with a higher rate in the next step until the drawdown stabilizes once more. This process is repeated at least three times (steps), with the equal duration. In this paper we tried to review some critical problems related to the step-drawdown test, which were revealed in the process of field practices and analyses. The problems, referred in this paper are mainly associated with the incorrect conceptual approach for analysis and incomplete data collection in the field test.

• Journal of Software Engineering Society
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• v.28 no.1
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• pp.7-12
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• 2019

Recently, as the weight of software in the weapon system increases, the quality of the software becomes a very important factor. In order to improve the quality of the weapon system software, DAPA(Defense Acquisition Program Administration) has institutionalized software reliability in Weapon System Software Development and Management Manual. The manual presents specific methods and procedures to improve the weapon system software quality. In order to meet the required reliability test standards specified in the manual, it is necessary to continuously detect and correct defects throughout the entire development period. However, it is difficult to build proper reliability test environment due to the cost of software reliability tools, setting up secured and separated network environment, and etc. Therefore, in this study, we propose an efficient environment construction method for software reliability test of defense industry field in restricted development environment and limited resources.

• Tunnel and Underground Space
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• v.32 no.4
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• pp.243-253
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• 2022

In this study, the cutting efficiency of TBE (Tunnel Boring Extender) was evaluated by using rotary cutting tester. In the rotary cutting test, a specimen which has a drilled hollow hole at the center was made of rock-like material. The specimen was cut by UDC (undercutting disc cutter) with spiral cutting path to simulate the cutting process of TBE. The cutting forces and specific energy were evaluated under different cutting conditions. The results indicated that the cutter forces of UDC linearly increased with the vertical and radial penetration depths. Among the three directional cutter forces, the normal force is larger than other force components. While the specific energy decreased with the two penetration depths, in particular, it was presumed that the specific energy was minimized at a certain value of the ratio of radial to vertical penetration depth.

• Korean Journal of Construction Engineering and Management
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• v.9 no.4
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• pp.193-205
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• 2008

Quality is an important keyword representing the corporate competitiveness and image in today' s construction industry. Especially in concrete construction, any problems or defects in fresh concrete can significantly degrade the entire quality and performance of the facility built. Thus, adequate quality inspection and testing must be exercised over the fresh concrete, if concrete with the required strength, durability and appearance is to be obtained. The testing of concrete delivered to the construction job site involves testing of fresh concrete and performing strength tests on hardened concrete. The principal tests conducted on fresh concrete include the slump test and tests for air and salt content. The temperature of fresh concrete should be checked out hot or cold weather concreting. The 7-day and 28-day strength of hardened concrete are also determined by compression tests on usually cylinder samples. However, it is very complex and time-consuming process requiring a lot of efforts to document those on-site concrete testing results and to accumulate their historical data. The primary objective of this study is to suggest a unique PDA and web-based system which enables an on-site quality manager to effectively conduct the concrete inspection and testing, automatically document and accumulate the collected historical data, and promptly obtain the approval from supervisors. Finally, it is anticipated that the effective use of the proposed PDA and web-based system would be able to improve reliability of the concrete quality inspection and testing data as well as significantly reduce the approval process.

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.99-106
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• 2000

The main advantage of incremental loading consolidation test is the simplicity of equipments that can be used. However, it is known that the incremental loading test has several deficiencies including long testing time, non-uniform stress state, high and variable rates of strain, very soft clay and problem of back pressure saturation. Due to these drawbacks, various testing methods including constant rate of strain consolidation test(CRS) were developed. In this paper, CRS consolidation test was performed with three different strain rate. The results were verified by the modified CRS theory of Wissa et al.(1971). And then the results obtained from the CRS consolidation tests were compared with those from incremental loading test and direct permeability test.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.161-163
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• 2012

웹 기반 서비스의 수요가 급속히 증가함에 따라, 다양한 분야의 웹 어플리케이션이 개발되고 있으며 기능 요구 사항도 복잡해 지고 있다. 이에 따라, 구현된 소프트웨어의 복잡도가 증가되어 기능 검증을 위한 시험의 중요성이 대두되고 있으나, GUI를 기반으로 하는 웹 어플리케이션의 특성 때문에 사용자 관점에서 다양한 기능시험을 수행하기 위해서는 많은 노력과 시간이 필요하다. 특히 최근에는 과거와 달리 다양한 브라우저가 사용됨에 따라, 다양한 브라우저 상에서의 웹 어플리케이션 기능시험을 필수적으로 해야 하기 때문에 시험 수행 시간을 줄일 수 있는 시험방안이 절실히 요구되고 있다. 본 논문에서는 공개 소프트웨어인 GUI 시험 자동화 도구를 활용하고, 테스트 자동화를 위한 테스트 케이스를 생성하여 다수의 브라우저 환경에서 동시에 자동으로 기능시험을 수행할 수 있게 함으로써, 시험 효율성을 극대화하기 위한 웹 어플리케이션 시험 자동화 방안을 제안한다. 실제 사례적용을 통하여, 시험 시간을 획기적으로 단축시키고, 4개의 브라우저에 대하여 동시 시험 수행이 가능함을 확인하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.9
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• pp.931-938
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• 2009

The flight test is last means of compliance to satisfy airworthiness standards and important to evaluate the performance and safety of the developed aircraft. The flight test technologies are obtained from great numbers of experiences and know-hows and protected. In addition, flight test should be conducted efficiently since its various test conditions and items. Therefore, it is requisite to secure efficient flight test methods. This paper discusses the flight test methods for take-off and landing performance and two kinds of techniques are proposed. By performing real flight tests, they are compared with each other and analyzed through the flight analysis.

• Nuclear industry
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• v.16 no.12 s.166
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• pp.70-77
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• 1996

원자력발전소에서 발생되는 방사성 폐기물 드럼 안에 있는 핵종과 그 양을 비파괴적인 방법으로 분석할 수 있는 방사성 폐기물 핵종 분석 장치가 개발되었다. 한전 전력연구원이 한국원자력연구소와 공동으로 개발한 이 장치는 기존의 계측 방법과 달리 슬라이드형 콜리메이터를 이용해 방사선량률 변화에 따라 드럼 안의 고방사능량까지 효율적으로 측정할 수 있는 시스템을 갖추고 있다. 현재 이 시스템은 실험실 성능 시험을 마치고 고리 제4폐기물 저장고에 설치되어 시험 운전중이며, 성능 검증 시험을 마친 후 전 원전에 설치될 예정이다.