• 한국군사과학기술학회지
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• 제19권2호
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• pp.145-154
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• 2016

In this paper, a pneumatic device for the deployment performance verification of canards deployed by inertia has been designed and the performance of the pneumatic device has been proven through analysis and tests. The pneumatic conveying process, orifice opening process and piston movement process of the pneumatic device were investigated by using numerical methods. The orifice diameter, pressure in a pressure tank and type of gas were regarded as the main design parameters of the pneumatic device. The error rate between analysis and test results under the same conditions was within 4 %. The accuracy of numerical methods used in this study were validated.

• Computers and Concrete
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• 제32권2호
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• pp.149-163
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• 2023

One of the main design parameters traditionally utilized in projects of geotechnical engineering is the uniaxial compressive strength. The present paper employed three artificial intelligence methods, i.e., the stochastic fractal search (SFS), the multi-verse optimization (MVO), and the vortex search algorithm (VSA), in order to determine the compressive strength of concrete (CSC). For the same reason, 1030 concrete specimens were subjected to compressive strength tests. According to the obtained laboratory results, the fly ash, cement, water, slag, coarse aggregates, fine aggregates, and SP were subjected to tests as the input parameters of the model in order to decide the optimum input configuration for the estimation of the compressive strength. The performance was evaluated by employing three criteria, i.e., the root mean square error (RMSE), mean absolute error (MAE), and the determination coefficient (R²). The evaluation of the error criteria and the determination coefficient obtained from the above three techniques indicates that the SFS-MLP technique outperformed the MVO-MLP and VSA-MLP methods. The developed artificial neural network models exhibit higher amounts of errors and lower correlation coefficients in comparison with other models. Nonetheless, the use of the stochastic fractal search algorithm has resulted in considerable enhancement in precision and accuracy of the evaluations conducted through the artificial neural network and has enhanced its performance. According to the results, the utilized SFS-MLP technique showed a better performance in the estimation of the compressive strength of concrete (R²=0.99932 and 0.99942, and RMSE=0.32611 and 0.24922). The novelty of our study is the use of a large dataset composed of 1030 entries and optimization of the learning scheme of the neural prediction model via a data distribution of a 20:80 testing-to-training ratio.

• 한국도로학회논문집
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• 제10권2호
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• pp.15-26
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• 2008

최근 들어 철근 부식, 콘크리트 포장표면의 박리파손, 환경 피해 등 염화물계 제설제의 사용에 따른 각종 피해가 보고되고 있으며, 이를 위해 대체 제설제의 개발을 위한 연구가 활발히 진행되고 있다. 하지만 개발된 제설제의 성능평가에 대한 연구는 대부분 실내실험을 위주로 한 기초적이고 제한적인 성능평가에 의존하고 있는 선정이다. 특히 제설제의 융빙성능은 제설제가 갖추어야 할 기본적인 성능으로, 합리적이고 체계적인 평가방법을 통한 융빙성능의 평가가 필수적이다. 본 연구에서는 기존 연구를 바탕으로 보다 구체적이고 현실적인 융빙성능 평가방법을 수립하였으며 그 절차에 따라 본 연구진에 의해 개발된 저염화물계 친환경 제설제인 EFD(Eco Friendly Deicer)의 융빙성능을 평가 및 검증하였다. 실내실험 결과, EFD는 국내 고속도로에서 사용 중인 습염식 제설제와 대등한 수준의 초기 융빙성능을 나타냈으며 2회의 현장살포 실험을 통해 EFD의 융빙성능을 검토한 결과, 전체적인 융빙성능이 습염식 제설제의 융빙 성능에 비해 큰 차이가 없음을 확인하였다.

• 한국항해항만학회지
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• 제39권1호
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• pp.15-21
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• 2015

GNSS를 이용한 정밀측위에서 미지정수 결정은 가장 중요한 과정이다. 정확한 미지정수를 추정하는 경우에는 수 mm에서 수 cm의 정밀한 측위결과를 가져오지만 부정확한 미지정수를 사용하는 경우에는 측위결과의 정확도와 정밀도를 보장할 수가 없다. 미지정수 결정은 IR(Integer Rounding), IB(Integer Bootstrapping), ILS(Integer Least Squares) 등의 기법을 기반으로 수행할 수 있다. 이중에서 ILS는 이론적, 실험적으로 가장 좋은 성능을 보여준다. 하지만 다른 기법들과 달리 ILS는 미지정수에 대한 후보를 검색하기 때문에 올바른 미지정수를 판단하기 위한 타당성 검정이 필요하다. 본 논문에서는 타당성 검정 기법간의 실험적인 비교 분석을 수행한다. 실험에는 타당성 검정 기법으로 자주 쓰이는 R-ratio, F-ratio, W-ratio가 사용되었다. 각 타당성 검정 기법의 성능을 정상동작, 검출, 미검출, 오검출로 나누어 평가하였다. 실험결과로 각 타당성 검정 기법의 장단점이 분명하게 나타났으며, 이를 통해 적용환경에 따라 기법이 선택되어야 함을 확인하였다.

• PNF and Movement
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• 제8권1호
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• pp.67-77
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• 2010

Purpose : The purpose of this study was to investigate the usefulness of clinical balance tests through the correlation of balance evaluation using by forceplate in elderly. Methods : Thirty nine healthy elderly subjects (14 males, 25 females) participated in the study. The subjects were evaluated with clinical balance tests [(Berg balance scale (BBS), Functional reach test (FRT), Tinetti's performance oriented mobility assessment (POMA), and one leg standing (OLS)]. Static balance evaluation was assessed by using forceplate. Center of pressure (COP) parameters were obtained using it as total path distance, total sway area, X mean frequency and Y mean frequency for 20 seconds in the following conditions: (1) comfortable standing with eyes opened and closed, (2) uncomfortable standing with eyes opened and closed. After static balance evaluation tested, dynamic balance evaluation was assessed. COP parameters were error distance and area during sine curve trace. COP parameters were movement time, error distance, and maintained time in the circle during COP movement task. Results : Clinical balance tests showed statistically significant correlation between static and dynamic balance evaluations. Among the clinical balance tests, the BBS, POMA, and OLS showed significant correlation with to assess the balance ability of elderly in clinical setting both evaluations. Conclusion : Clinical balance tests can be recommended in clinical setting because of low costs and simplicity.

• 가정간호학회지
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• 제24권1호
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• pp.14-22
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• 2017

Purpose: To study aimed to examine the impact of the Nursing and Care=giving Integrated Service on nursing work performance, nurse' job satisfaction, and patient safety. Methods: A total of 66 nurses were selected as participants, comprising 30 nurses working in Nursing and Care=giving Integrated Service hospital ward, and 33 nurses working in a general hospital ward with a similar patient and disease group and distributed moderately. For data analysis, t-tests, ANOVA, and $X^2$ tests were conducted. Results: Nursing work performance in the Nursing and Care=giving Integrated Service ward was higher than that in the general hospital ward, but this difference was not statistically significant. Conversely, job satisfaction was lower among nurses in the Nursing and Care=giving Integrated Service ward, although again the difference was not significant. However, the Nursing and Care=giving Integrated Service ward had a significantly lower rate of safety-related accidents in patients compared to the general hospital ward. Conclusion: In order to expand and improve patient safety and other aspects of the Nursing and Care=giving Integrated Service, there is a need to establish a mediation strategy for increasing nurses' work performance and job satisfaction.

• 한국도로학회논문집
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• 제15권1호
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• pp.1-9
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• 2013

PURPOSES: The purpose of this study is to evaluate physical properties, durability, fatigue resistance, and long-term performance of poly-urethane concrete (PU) which can be possible application of thin layer on long-span orthotropic steel bridge and to check structural stability of bridge structure. METHODS : Various tests of physical properties, such as flexural strength, tensile strength, bond strength and coefficient of thermal expansion tests were conducted for physical property evaluation using two types of poly urethane concrete which have different curing time. Freezing and thawing test, accelerated weathering test and chloride ion penetration test were performed to evaluate the effect of exposed to marine environment. Beam fatigue test and small scale accelerated pavement test were performed to assess the resistance of PU against fatigue damage and long-term performance. Structural analysis were conducted to figure out structural stability of bridge structure and thin bridge deck pavement system. RESULTS: The property tests results showed that similar results were observed overall however the flexural strength of PUa was higher than those of PUb. It was also found that PU materials showed durability at marine environment. Beam fatigue test results showed that the resistances of the PUa against fatigue damage were two times higher than those of the PUb. It was found form small scale accelerated pavement test to evaluate long-term performance that there is no distress observed after 800,000 load applications. Structural analysis to figure out structural stability of bridge structure and thin bridge deck pavement system indicated that bridge structures were needed to increase thickness of steel deck plate or to improve longitudinal rib shape. CONCLUSIONS: It has been known that the use of PU can be positively considered to thin layer on long-span orthotropic steel bridge in terms of properties considered marine environment, resistance of fatigue damage and long-term performance.

• 수면정신생리
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• 제6권2호
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• pp.143-148
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• 1999

목 적: 지각 장애가 어떤 뇌의 부위와 기능에 장애가 있을 때 발생되는지를 알아보기 위해 정신과와 뇌손상 환자에서 신경심리 검사와 지각 장애와 관계성을 조사하였다. 방 법: 정신과 환자 69명, 뇌손상 환자 50명, 총 119명에서 Halstead Reitan 신경 심리 검사와 K-WAIS, MMPI를 시행하였다. MMPI 항목 중 지각 장애와 관계되는 9개 항목에서 산출된 점수와 신경심리 검사의 결과와의 상관 관계를 조사하였다. 또 정신과 환자에서 지각 장애 점수가 높은 지각 장애군 21명과 지각 장애가 없는 지각 장애 17명을 t-test로 비교하였다. 결 과: 뇌손상 환자군에서 지각 장애가 전두엽 기능을 보는 범주화 검사, 선로 잇기 검사, 촉각 수행 검사, 손끝 숫자 쓰기 검사와 우측 반구 기능을 보는 촉각 수행 검사의 위치, 동작성 점수, 빠진곳 찾기, 차례 맞추기, 토막 짜기 등과 유의한 상관 관계를 보였다. 또 피질하 기능을 보는 숫자 상징, 산수, 숫자 외우기와 유의한 상관 관계를 보였다. 정신과 환자의 높은 지각 장애군은 우측 반구 편측화 지수와 빠진 곳 찾기, 토막 짜기와 같은 우측 반구 기능에서 유의한 차이가 있었고, 또 이해, 어휘, 공통성과 같은 좌측 반구 기능에서도 유의한 차이가 있었다. 결 론: 지각 장애는 전두엽, 우측 반구, 피질하 구조의 기능과 깊은 연관성을 가지고 발생이 되며, 정신과 환자군에서는 좌측 반구의 기능도 영향을 주는 것으로 생각된다.

• Communications for Statistical Applications and Methods
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• 제6권1호
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• pp.159-168
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• 1999

We introduce a new conditional signed-rank test for the tree alternatives comparing several treatments with a control in the randomized block design. We demonstrate its performance by comparing with 3 classes of signed-rank tests proposed by Park et al.(1991) in some general situations. In most cases the proposed procedure is simpler to compute and has better power than others.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.490-495
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• 2001

This paper deals with an analysis and countermeasure for improving the shock performance of laptop computers. The shock analysis is carried out by using the commercial program of LS-DYNA3D. Also the analysis is verified by the measurements from modal tests and shock tests. The available countermeasures are investigated theoretically and experimentally to find the effective methods of reducing the shock acceleration on hard disk driver during one side fall test. The hard disk drive is the most sensitive part in a laptop computer. This research shows the effects of the spring constant of rubber pad, the reinforcement of mechanical parts and the location of a hard disk driver, on the shock reduction.