• International Journal of Automotive Technology
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• 제7권7호
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• pp.813-819
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• 2006

As the vehicle becomes bigger and faster, the importance of vehicle stability in an extreme driving condition caused by sudden steering, road condition or unexpected case has been emphasized. The ESP system is being utilized to improve the handling performance and the vehicle stability. In this study, we implemented various tests and proposed estimation methods for ESP characteristics in extreme driving situations. The estimation methods for ESP proposed in this paper are expected to facilitate developing the control logic and improving the performance of the ESP system.

• Advances in concrete construction
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• 제1권3호
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• pp.227-237
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• 2013

Modal testing, widely accepted and applied method for determining the dynamic characteristics of structures for operational conditions, uses known or unknown vibrations in structures. The method's common applications includes estimation of dynamic characteristics and also damage detection and monitoring of structural performance. In this study, the structural identification of concrete arch dams is determined using ambient vibration tests which is one of the modal testing methods. For the purpose, several ambient vibration tests are conducted to an arch dam. Sensitive accelerometers were placed on the different points of the crest and a gallery of the dam, and signals are collected for the process. Enhanced Frequency Domain Decomposition technique is used for the extraction of natural frequencies, mode shapes and damping ratios. A total of eight natural frequencies are attained by experimentally for each test setup, which ranges between 0-12 Hz. The results obtained from each ambient vibration tests are presented and compared with each other in detail. There is a good agreement between the results for all measurements. However, the theoretical fundamental frequency of Berke Arch Dam is a little different from the experimental.

• 한국수학교육학회지시리즈A:수학교육
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• 제42권2호
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• pp.159-176
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• 2003

From the mid-1990s in Korea, performance assessment has been continuously emphasized in school mathematics and thus many researchers and teachers have been steadily studying this topic. But the concepts relevant to performance assessment and its purposes are very confusing because the mathematics educators' different views and voices are vary. As a result most mathematics teachers experience trouble in executing performance assessment properly and effectively in their math class. This unability for proper execution of performance assessment was once again revealed in this study which dealt with 15 articles on performance assessment. These 15 articles includes almost every article written on the topic of performance assessment that have been published in 4 domestic journals since December 1997. By examining this inability, it is required that its concepts and purposes should be organized with a common view and newly defined in the near future. Therefore, to successfully accomplish this, this paper outlines the basic problems on the understanding of performance assessment as follows: ㆍWhat is the relationship between performance assessment and alternative assessment\ulcorner ㆍWhat is the proper types(methods) of performance assessment\ulcorner ㆍIs the subject test a type of performance assessment\ulcorner ㆍWhat is the difference between subject test and essay test\ulcorner ㆍWhat is the relationship between performance assessment and performance tasks\ulcorner ㆍWhat is the relationship between performance tests and project method\ulcorner ㆍWhat is a project method\ulcorner ㆍIs it assessment standard or scoring standard to score a test result\ulcorner ㆍWhat is the difference between analytic scoring method and holistic scoring method?

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제25권1호
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• pp.13-20
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• 2022

Purpose: Hydrogen-methane breath tests are used to diagnose carbohydrate malabsorption and small intestinal bacterial overgrowth. The COVID-19 pandemic has driven the modification of procedures as breath tests are potentially aerosol-generating procedures. We assessed the effect of delayed analysis of breath samples, facilitating the at-home performance of breath testing. Methods: Children provided two breath samples at every step of the lactose breath test. The samples were brought back to the clinic, and one set of samples was analyzed immediately. The second set was stored at room temperature and analyzed 1-4 days later. Results: Out of the 73 "double" lactose breath tests performed at home, 33 (45.8%) were positive. The second samples were analyzed 20 to 117 hours after the first samples (41.7±24.3 hours). There was no significant difference in the hydrogen concentration between the first and second sets (Z=0.49, p=0.62). This was not the case for methane, which had a significantly higher concentration in the second breath samples (Z=7.6). Conclusion: Expired hydrogen levels remain stable in plastic syringes if preserved at room temperature for several days. On the other hand, the delayed analysis of methane appeared to be less reliable. Further research is needed to examine the impact of delayed analysis on methane and hydrogen concentrations.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.III
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• pp.560-568
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• 2000

The aims of this research were to investigate the preprocessing effect of spectrum data on prediction performance and to develop a robust model to predict SSC in intact apple. Spectrum data of 320 Fuji apples were measured with the on-line transmittance measurement system at the wavelength range of 550∼1100nm. Preprocess methods adopted for the tests were Savitzky Golay, MSC, SNV, first derivative and OSC. Several combinations of those methods were applied to the raw spectrum data set to investigate the relative effect of each method on the performance of the calibration model. PLS method was used to regress the preprocessed data set and the SSCs of samples, and the cross-validation was to select the optimal number of PLS factors. Smoothing and scattering corection were essential in increasing the prediction performance of PLS regression model and the OSC contributed to reduction of the number of PLS factors. The first derivative resulted in unfavorable effect on the prediction performance. MSC and SNV showed similar effect. A robust calibration model could be developed by the preprocessing combination of Savitzky Golay smoothing, MSC and OSC, which resulted in SEP= 0.507, bias=0.032 and R$^2$=0.8823.

• 한국항공우주학회지
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• 제37권9호
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• pp.931-938
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• 2009

비행시험은 개발 항공기의 다양한 성능검증을 포함하여 감항기술기준에 대한 안전성을 입증하는 최종시험으로서 중요성이 크다. 특히, 민간 항공기의 비행시험은 개발업체의 경험 및 노하우에 의해 기술 보호성격이 강하며, 다양한 시험항목과 비행조건에 의해 비용이나 시간측면에서 효율적인 비행시험 수행 및 비행시험 기법의 확보는 필수적이다. 본 논문에서는 이륙 및 착륙성능 입증을 위한 이착륙 비행시험에 대해 지상관측법과 DGPS를 활용한 비행시험 기법을 제안하고 실제 비행시험을 수행하여 그 결과를 비교하였다.

• 설비공학논문집
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• 제16권1호
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• pp.62-69
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• 2004

Thermoelectric module is a device that can produce cooling in a direct manner using the electrical energy. The purpose of this study is to investigate the performance of thermoelectric module and cooling system equipped with the thermoelectric module. The performance of a thermoelectric module is estimated using two methods; theoretical analysis based on one-dimensional energy equations and experimental tests using heat source, heat sink and brass conduction extenders. For the thermoelectric cooling system, the temperatures in the chamber are recorded and then compared with those of lumped system analysis. The results show that the cooling capacity and COP of the thermoelectric module increases as the temperature difference between hot and cold surface decreases, and there is particular current at which cooling capacity reaches its maximum value. The experimental results for the thermoelectric cooling system are similar to those of lumped system analysis.

• 한국콘텐츠학회논문지
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• 제19권6호
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• pp.565-574
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• 2019

본 연구는 혈액은행 자동화 장비 QWALYS-2 up (Diagast, Loos Cedex, France)의 유용성을 평가하기 위하여 수행되었다. 2013년 10월 1일부터 10월 31말까지 1개월간 강원대학교병원 진단검사의학과에 의뢰된 ABO 및 RhD 혈액형 검사 1,636건, 항체선별검사 1,374건을 대상으로 하였고, ABO 및 RhD 혈액형 검사의 평가는 200건을 대상으로 하였다. 혈액은행 자동화장비의 경제성을 평가하기 위해서는 2018년 12월을 기준으로 장비 도입 전인 2013년 1월부터 장비 도입 후 5개년의 ABO 및 RhD 혈액형 검사와 항체선별검사의 단가를 비교하였다. 본 연구의 주요 결과는 ABO 및 Rh 혈액형 검사 결과, 슬라이드나 시험관을 이용한 수기법의 결과가 100% (200/200) 일치하였고 동종항체 선별검사 결과, 불일치 3검체는 수기법으로 재검을 한 결과, 음성을 보여 QWALYS-2 up에서 위양성의 결과를 나타냈으나, 반응의 정도를 비교한 결과 QWALYS-2 up에서 상대적으로 높게 나타났다. 결론적으로 혈액형자동화 장비 도입 전후의 효과를 평가한 결과, 기존의 수기법과 비교하였을 때 높은 일치율을 보였으며, 정확도 면에서도 신뢰할 만한 것으로 판단되었다. 도입 전후의 시약의 비용은 증가하였지만 인건비의 절감을 감안하면 경제적으로도 유용하다고 평가할 수 있다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권14호
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• pp.5889-5897
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• 2015

Background: The performance of combined testing visual inspection with acetic acid (VIA) and cervical cytology tests might differ from one setting to another. The average estimate of the testing accuracy across studies is informative, but no meta-analysis has been carried out to assess this combined method. Objective: The objective of this study was to estimate the average sensitivity and specificity of the combined VIA and cervical cytology tests for the detection of cervical precancerous lesions. Materials and Methods: We conducted a systematic review and a meta-analysis, according to the Cochrane Handbook for Systematic Review of Diagnostic Test Accuracy. We considered two cases. In the either-positive result case, a positive result implies positivity in at least one of the tests. A negative result implies negativity in both tests. In the both-positive case, a positive result implies having both tests positive. Eligible studies were identified using Pubmed, Embase, Website of Science, CINHAL and COCRANE databases. True positive, false positive, false negative and true negative values were extracted. Estimates of sensitivity and specificity, positive and negative likelihood (LR) and diagnostic odds ratios (DOR) were pooled using a hierarchical random effect model. Hierarchical summary receiver operating characteristics (HSROC) were generated and heterogeneity was verified through covariates potentially influencing the diagnostic odds ratio. Findings: Nine studies fulfilled inclusion criteria and were included in the analysis. Pooled estimates of the sensitivities of the combined tests in either-positive and both-positive cases were 0.87 (95% CI: 0.83-0.90) and 0.38 (95% CI: 0.29-0.48), respectively. Corresponding specificities were 0.79 (95% CI: 0.63-0.89) and 0.98 (95% CI: 0.96-0.99) respectively. The DORs of the combined tests in either-positive or both-positive result cases were 27.7 (95% CI: 12.5-61.5) and 52 (95% CI: 22.1-122.2), respectively. When including only articles without partial verification bias and also a high-grade cervical intraepithelial neoplasia as a threshold of the disease, DOR of combined test in both-positive result cases remained the highest. However, DORs decreased to 12.1 (95% CI: 6.05-24.1) and 13.8 (95% CI: 7.92-23.9) in studies without partial verification bias for the combined tests in the either-positive and both-positive result cases, respectively. The screener, the place of study and the size of the population significantly influenced the DOR of combined tests in the both-positive result case in restriction analyses that considered only articles with CIN2+ as disease threshold. Conclusions: The combined test in the either-positive result case has a high sensitivity, but a low specificity. These results suggest that the combined test should be considered in developing countries as a primary screening test if facilities exist to confirm, through colposcopy and biopsy, a positive result.

• Structural Engineering and Mechanics
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• 제44권6호
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• pp.775-799
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• 2012

This work approaches the structural performance of masonry arches that have a small ratio between number of vossoirs and span length. The aim of this research is to compare and validate three different methods of analysis (funicular limit analysis F.L.A., kinematic limit analysis K.L.A. and plane stress Finite Element Analysis F.E.A.) with an experimental campaign. 18 failure tests with arches of different shapes and boundary conditions have been performed. The basic failure mechanism was the formation of enough hinges in the geometry. Nevertheless, in few cases, sliding between vossoirs also played a relevant influence. Moreover, few arches didn't reach the collapse. The FLA and KLA didn't find a solution close to the experimental values for some of the tests. The low number of vossoirs and joints become a drawback for an agreement between kinematic mechanism, equilibrium of forces and geometry constraints. FLA finds a lower bound whereas KLA finds an upper bound of the ultimate load of the arch. FEA is the most reliable and robust method and it can reproduce most of the mechanism and ultimate loads. However, special care is required in the definition of boundary conditions for FEA analysis. Scientific justification of the more suitability of numerical methods in front of classic methods at calculating arches with a few vossoirs is the main original contribution of the paper.