• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.3
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• pp.277-289
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• 2011

This study proposes a new testing method for shear bearing capacity of FRP-concrete interface, which could well consider a loading condition corresponding to a tunnel lining undergoing axial compression and could be easily carried out with a simply specified specimen. A parametric study is carried out for capturing an optimized condition of coarse-sand coating of FRP, which governs shear bearing capacity of FRP-concrete interface, by using the proposed testing manner in this study. From the parametric study, it is shown that the proposed testing method is reasonably feasible in comparison with the existing testing methods. An optimum condition of coated sand size and sand density is given for the shearing capacity of FRP-concrete interface.

• Journal of the military operations research society of Korea
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• v.33 no.1
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• pp.117-133
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• 2007

The weapon accuracy is a basic measure of performance in the area of weapon system acquisition. It requires the establishment of correct concept and the T&E methods. Existing T&E method for aircraft weapon systems have not considered types of exact hitting area for various weapons. This study intends to suggest an optimal T&E methods in Korean T&E environment. In order to sampling and to test aircraft weapon accuracy, we need probability and statistic theories. There are many types of CEP(Circular Error Probable) methods. We recommend 2 types of CEP methods which are Lockheed Martin CEP method and Johnson CEP method. Also, suggest some other T&E methods. These methods can be used to accuracy test in the area of weapon system acquisition in the future.

• 전기의세계
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• v.38 no.11
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• pp.34-47
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• 1989

본고에서는 OF케이블의 gas분석에 관한 언급을 제외하고는 주로 CV케이블의 전기적 특성면에서의 절연열화 진단에 관하여 가장 실용화에 접근한 시험법과 측정결과를 개략적으로 기술하였다. 그러나 소개하지 못한 연구시험중에 있는 신기술도 많이 있다. 다만, 이 여러가지 시험법과 이론이 증명하듯이 최근 전력 케이블의 열화진단 기술을 확립하려는 많은 노력이 경주되고 있다는 것이다. 앞으로 머지않아 이 결과들이 정리되어 최적의 케이블 진단기술이 확립될 것이며 이에따라 전력케이블의 절연파괴 사고를 미연에 방지하므로써 전력공합신뢰도 향상에 이바지 하게 될것으로 확신한다.

• Proceedings of the Korea Society for Simulation Conference
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• 1999.04a
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• pp.204-211
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• 1999

항공기, 자동차, 전차 등 차량의 시스템 또는 운동의 시뮬레이션에서는 다양한 종류의 불연속적인 파라미터 값들이 데이터 테이블의 형태로 주어지게 되는데, 본 연구에서의 관심은 적분 스텝의 크기가 고정되는 일반적인 실시간 시뮬레이션의 제약 하에서 기존의 검색 기법들을 비교하고, 최적의 검색 기법을 개발하는 것이다. 본 연구에서는 전통적으로 수치해석, 시뮬레이션, 데이터베이스 등 다양한 학문 및 응용기술 분야에서 개발된 데이터 검색 기법들을 조사하여 비교하였다. 또한, 다양한 크기와 형태의 데이터 테이블들을 사용하여 수치비교시험을 수행하였는데, 그 경향은 이론에 근거한 예상과 대체로 일치하였다. 한편, 검색하고자 하는 파라미터 값이 임의의 dynamics를 갖고 변한다면, 이러한 정보를 이용하여 주어진 데이터 테이블 내의 검색 영역을 축소 시켜 검색속도를 향상시킬 수가 있다. 다양한 수치시험에서 이분 검색법(bisection method)은 축소된 테이블의 크기에만 영향을 받지만 보간 검색법(interpolation method)과 그 변형 기법들은 검색 대상 테이블들의 축소로 데이터의 형태가 직선형이 되는 효과를 얻기 때문에 검색속도를 단축시키는데 매우 탁월한 효과를 나타내었다. 결론적으로 dynamic-window 개념을 도입한 보간 검색법과 그 변형들이 이론적으로도 실험적으로도 최적의 검색속도를 보장함이 입증되었다.

• Journal of the Korea Concrete Institute
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• v.21 no.4
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• pp.523-530
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• 2009

For designing concrete structures, engineers are provided data from unidirectional flexure test in most cases. But real structural components such as pavements and deck panel are subjected to multiaxial stress throughout their body. Therefore, biaxial flexure test for concrete may be considered as a gage of the performance of concrete in service. In this paper, we propose the optimum biaixial flexture test (BFT) to measure the biaxial flexural strength of concrete. This method are an improved version of the ring-on-ring test which have been used extensively in the fields of ceramics and biomaterials. The optimum geometry of the test specimen was determined by using a three-dimensional finite element analysis. A series of test data obtained from the proposed test method is provided to show that the proposed optimum biaxial flexure test method can be used to identify the biaxial tensile strength of concrete.

• Journal of the Korean Geotechnical Society
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• v.39 no.2
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• pp.5-17
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• 2023

In this study, a classification and uniaxial compression test of soil was conducted on 15 collapsed sites to use ground improvement with excellent protection effect owing to the increase of localized heavy rain in Korea. The Casagrande method and fall cone test were performed on the field soil to derive an expression for comparing liquid limit and plastic limit values, soil classification, and correlation between each other. By deriving the optimal mixing ratio of the ground improvement agent using uniaxial compressive strength for each soil classification, the classification of the fine-grained soil was not clear owing to the proficiency difference and test error. However, after classifying using the fall cone test, it was possible to suggest a clear optimal mixing ratio.

• Analytical Science and Technology
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• v.33 no.6
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• pp.262-273
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• 2020

A fluorine content analysis method for krill oils, which is a representative oil formulation in foods, was developed in compliance with the Korea Food and Drug Ministry's "Guidelines for Validation of Testing Methods Related to Food". Using this method for krill oils, the presence of impurities was evaluated via combustion-ion chromatography (C-IC). A review of published technical data on fluorine in krill oils showed that while the traditional wet potentiometric method was typically used, it was not reliable. Moreover, there was no food testing/analysis laboratory in Korea to perform a fluorine test analysis on such an oil matrix. Therefore, we identified halogen (fluorine) tests, developed to national and international standards, and developed a test method suitable for krill oils by selecting a C-IC method that is sufficiently applicable to the oil matrix. Based on the characteristics of the oil matrix, the optimal test method was established through various experiments by reviewing the concerns related to loss and interference in the preparation and introduction of samples. The fluorine content test was carried out on 11 krill oil products that were purchased online. Most products (with the exception of only one) were found to contain less than the reporting limit obtained by the test method. Furthermore, after additional testing, a high fluorine content of approximately 2,000 ~ 3,000 mg/kg was detected on the krill surface, although the concentration varied depending on the area of the krill. A comparison with samples from two ISO/IEC 17025 testing laboratories confirmed that there was no significant difference in the statistical analysis results obtained by ANOVA among the three laboratories. A testing guide for fluorine content analysis was completed.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1239-1244
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• 2010

중금속 및 유류 오염토양 정화를 위해 효율적인 토양세척법과 공정 선정을 목적으로 최적의 오염정화 설계인자를 제시하기 위한 실험적 연구를 수행하였다. 실험분석 항목은 구리, 납, 아연을 포함하는 중금속항목과 총석유계탄화수소(TPH)인 유류항목에 대해 흡광광도법(absorptiometric analysis), 기체 크로마토그래피(gas chromatography)법을 이용하여 단계별로 분석하였다. 실험방법은 최적 세척용매 결정시험, 최적 세척시간 도출시험, 최적 진탕비(S/W ratio) 결정시험 등을 통해 얻어진 결과를 토대로 계면활성제 첨가량별 중금속 용출영향 분석시험 순으로 실시하였다. 실험결과 세척용매인 염산 0.1mole, 체류시간 1시간, 진탕비 1:3 조건에서 오염물질의 저감효과가 우수하게 나타났으며, 이들 조건을 적용하였을 때 1%의 계면활성제를 세척용매에 첨가하였을 경우 추가적인 오염물질의 농도 저감효과가 있는 것으로 분석되었다.

• Journal of Marine Life Science
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• v.9 no.1
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• pp.9-21
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• 2024

Paralytic shellfish poisoning (PSP) including Saxitoxin (STX) is caused by harmful algae, and poisoning occurs when the contaminated seafood is consumed. The mouse bioassay (MBA), a standard test method for detecting PSP, is being sanctioned in many countries due to its low detection limit and the animal concerns. An alternative to the MBA is the Neuro-2a cell-based assay. This study aimed to establish various test conditions for Neuro-2a assay, including cell density, culture conditions, and STX treatment conditions, to suit the domestic laboratory environment. As a result, the initial cell density was set to 40,000 cells/well and the incubation time to 24 hours. Additionally, the concentration of Ouabain and Veratridine (O/V) was set to 500/50 μM, at which most cells died. In this study, we identified eight concentrations of STX, ranging from 368 to 47,056 fg/μl, which produced an S-shaped dose-response curve when treated with O/V. Through inter-laboratory variability comparison of the Neuro-2a assay, we established five Quality Control Criteria to verify the appropriateness of the experiments and six Data Criteria (Top and Bottom OD, EC₅₀, EC₂₀, Hill slop, and R² of graph) to determine the reliability of the experimental data. The Neuro-2a assay conducted under the established conditions showed an EC₅₀ value of approximately 1,800~3,500 fg/μl. The intra- & inter-lab variability comparison results showed that the coefficients of variation (CVs) for the Quality Control and Data values ranged from 1.98% to 29.15%, confirming the reproducibility of the experiments. This study presented Quality Control Criteria and Data Criteria to assess the appropriateness of the experiments and confirmed the excellent repeatability and reproducibility of the Neuro-2a assay. To apply the Neuro-2a assay as an alternative method for detecting PSP in domestic seafood, it is essential to establish a toxin extraction method from seafood and toxin quantification methods, and perform correlation analysis with MBA and instrumental analysis methods.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.4
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• pp.1-6
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• 1992

The finite difference simulation method for ship waves is introduced for hull form improvement. Numerical simulations were performed for a series of modified hull forms and the simulated results were used for the determination of the better hull forms. A 4,400 TEU container carrier which was designed and experimented in towing tank was chosen for the purpose. The calculation results are compared with those of model test, of simplified Neumann-kelvin problems and of Rankine source method. In this study, it is shown that the combination of the computer simulation by our method with the experiment provides one of the most economical and reliable procedures of hull form improvement and that the degree of accuracy of this method is so high that it can cope with very practical design purposes.