• 한국항공운항학회지
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• 제12권3호
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• pp.13-24
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• 2004

It is easier to view flow visualization by using a water tunnel rather than a smoke wind tunnel because of low speed at same Reynolds number. Using a water tunnel also produces more definite flow visualization by the use of various color dyes. The flow uniformity in test section is very significant for accuracy of the test because most flow experiments elicit results through the installation of a model in uniform flow. The purpose of small-size desktop-type water tunnel is not to produce quantitative measurements, but rather to give a visualization of the fluid flow phenomenon. However, uniformity in the test section affects the accuracy of the results. Accordingly, this research estimates uniformity in a water tunnel test section by using the commercially available CFD code FLUENT. Results of the CFD analysis show that the flow uniformity of the test section is good.

• Communications for Statistical Applications and Methods
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• 제7권2호
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• pp.563-573
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• 2000

In this thesis, we propose the test statistic for ordered alternatives on c-sample ranked set samples(RSS). The proposed test statistic JRSS is Jonckheere type statistic using the median of the i-th samples in each cycle. We obtained the asymptotic property of the proposed test statistic and the asymptotic relative efficiencies of the proposed test statistic with respect to J SRS which Jonckheere type statistic on simple random samples(SRS). From the simulation works, J RSS is superior to J SRS. We compared the empirical powers of J RSS with respect to U RSS on ranked set sample and U SRS on simple random sample using all samples, which are proposed by Kim, Kim and Lee(1999). The powers of J RSS are nearly the same values when entire sample size is large. J RSS is superior to U RSS. J RSS is simpler than U RSSon calculating process.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 춘계학술대회 논문집
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• pp.411-418
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• 2001

The initial analysis frequencies of the isolated test structure for seismic excitation tests give quite higher values to the actual modal test results. This large difference was redulted from some uncertainties in analysis modeling of several connection regions between column and upper beam, cross bars of the isolated structure. A modified simple analysis model is developed representing the actual dynamic behaviors of the test model, and the seismic analysis responses of the simple model are compared with those of the seismic tests.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.529-536
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• 2005

Based on an estimating method for post-cyclic strength and stiffness with cyclic triaxial tests, Direct Simple Shear (DSS) tests were carried out to confirm whether the method can be adapted to DSS test on fine-grained soils: silty clay, plastic silt, and non-plastic silt. Results from post-cyclic DSS tests were interpreted by a modified method as adopted for post-cyclic triaxial tests. In particular, influence of plasticity index for fine-grained soils was emphasised. Findings obtained from the present study are: (i) the higher the plasticity index of fine-grained soils is, the less not stiffness ratio but strength ratio decreases with increment of a normalised excess pore water pressure; and (ii) post-cyclic strength and stiffness results from DSS tests agree well with those predicted by the method modified from a procedure used for triaxial test results.

• 한국응급구조학회지
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• 제3권1호
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• pp.20-32
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• 1999

The purpose of this retrospective research of 603 patients who were transferred to the emergency medical center of university hospital from 1 Jan, 1998 to 31 Jan, 1998 was making of basic data for emergency medical transfer system improvement countermeasure and the point at issue of overlapping reexamination ststus of patients transfered to emergency medical center of university hospital from 1,2 level hospital. The data analysis was done by SPSS, t-test, ANOVA, Pearson correlation. The results were as follows: 1. Male to female ratio was 1.7:1 and peak age group was patients over forties and under nine years of age(70.5%) 2. Traumatic patients were 17.8%, motor vehicle accident patients were 16.7% and Non-traumatic patients were 65.3%. Transferring hospital was divided into 2groups: primary hospital, secondary hospital. The majority was secondary hospital(73.3%). The result of symptom severity classification of patients transferred to 3rd emergency medical center was urgent patients 32.5%, emergency patients 33.58%, non-emergency patients 34.0% 3. Most highest score items amoung overlapping reexamination of patients transfered to emergency medical center of university hospital from 1,2 level hospital were CBC test, simple X-ray (0.93점), CBC test(0.97점), urin test(0.88점), chemistry test(0.94점), simple X-ray(0.98점), CT(0.42점), EKG(0.89점) amoung overlapping reexamination of motor vehicle accident patients were more higher reexamination score than traumatic patients and non-traumatic patients 4. CBC test(P<0.001), urin test(P<0.001), chemistry test(P<0.001), simple X-ray(P<0.001), CT(P<0.01), EKG(P<0.001) amoung overlapping reexamination of patients in 2 level hospital were more higher reexamination score than 1 level hospital patients 5. About symptom severity classification of patients transferred to 3rd emergency medical center, CBC test(P<0.001), urin test(P<0.001), chemistry test(P<0.001), simple X-ray(P<0.01), CT(P<0.001), EKG(P<0.001) amoung overlapping reexamination items in urgent patients were more higher reexamination score than other patients 6. Influencing variation for overlapping reexamination in hospital was CBC test(P<0.001), CT (P<0.001), MRI (P<0.05).

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2004년도 가을 학술발표논문집 Vol.31 No.2 (2)
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• pp.490-492
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• 2004

소프트웨어 개발 프로세스의 평가를 통해 소프트웨어 프로덕트의 품질을 높이려는 다양한 시도들이 행해지고 있다. 소프트웨어 테스트 프로세스는 소프트웨어 개발 프로세스 중에서도 소프트웨어 프로덕트의 품질 향상에 직접적인 영향을 끼치므로, 이에 대한 체계적인 개선이 필요하다. 본 논문에서는 프로세스의 품질과 프로덕트의 품질을 동시에 고려하는 소프트웨어 테스팅 모델인 SETP 핵심 모델과 이를 지원하는 자동화 도구(Legba)를 제안한다.

• Communications for Statistical Applications and Methods
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• 제10권2호
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• pp.257-266
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• 2003

Distribution-free estimation methods are proposed for slope, $\beta$ in the simple linear regression model. In this paper, we suggest the point estimators using the sequential slope based on sign test and Wilcoxon signed rank test. Also confidence intervals are presented for each estimation methods. Monte Carlo simulation study is carried out to compare the efficiency of these methods with least square method and Theil´s method. Some properties for the proposed methods are discussed.

• 응용통계연구
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• 제5권1호
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• pp.29-39
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• 1992

단순선형회귀모형에서 어떤 미지의 시점을 전후하여 회귀계수에 변화가 있었는지에 대한 통계적 가설을 검정하고 변화점의 추정방법을 논의한다. 이차형식의 통계량을 제안하고 그 근사분포 및 유의수준제어를 살펴보았다. 또한 하나의 예를 통하여 제안된 방법을 적용하고 우도비검정과 비교하였다.

• 한국강구조학회 논문집
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• 제9권3호통권32호
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• pp.377-390
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• 1997

본 연구는 콘크리트충전 각형강관을 이용한 기둥-보 접합부에 있어서 시공성과 충전성을 고려하여 철근으로 보강한 콘크리트충전 각형강관 기둥-H형강보 접합부를 제시하고, 1차적으로 보의 인장플랜지와 충전 각형강관 기둥 접합부와의 인장거동을 실험적으로 관찰한 후, 내진 설계 개념을 적용하여 수평 하중을 반복적으로 가할 경우의 접합부 실험을 실시하고 제시한 접합부의 내력 및 변형 특성을 파악한다. 실험결과로부터 항복선이론을 적용하여 내력을 평가하고 접합부의 내력식을 제안하며, 향후 국내의 콘크리트충전 강관구조 규준 제정에 필요한 기초 자료를 제시하는데 그 목적이 있다.

• 대한기계학회논문집A
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• 제37권10호
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• pp.1239-1249
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• 2013

본 연구에서는 zircaloy-4 판재에 대해 바우싱거 효과를 고려한 경화거동 예측모델을 구축했다. 금속소재 가공에서 인장 후 압축 시 항복응력이 감소한다. 이에 스프링백 해석 시 바우싱거 효과를 반드시 고려해야 한다. Simple shear 시험에서 적정 시편크기 및 적정 조임토크에 대한 결정법을 제시했다. 5 가지 재료에 대한 simple shear 시험을 통해 응력-변형률 곡선을 구했다. 또한 유한요소해석을 활용해 simple shear 하중-변위 곡선으로부터 유효응력-변형률 곡선으로 변환과정을 소개했다. 등방/운동성 경화 조합모델을 활용해 simple shear 순/역방향 시험을 모사했다. 이때 각 경화계수에 따른 하중-변위 곡선 변화를 관찰하고, zircaloy-4에 대한 경화계수를 결정했다.