• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2212-2216
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• 2008

본 연구는 하도특성의 불규칙으로 인해 수위와 유량이 단일 관계가 형성되지 않은 경우와 유수의 흐름이 지속되어 GZF 측정이 어려운 경우에 구간분리와 GZF를 결정하는 곡선식 개발 방법론이라 할 수 있다. 첫번째 연구과제는 저수위 구간 수위-유량관계곡선식의 GZF 추정방법의 개선에 관한 연구이다. 다음과 같은 연구를 수행하기 위해서 GZF의 변화에 따라 곡선식의 신뢰도를 분석할 수 있는 프로그램을 개발하였다. 본 연구에서 개발한 프로그램은 사용자들이 쉽게 이용할 수 있는 엑셀 VBA(Visual Basic for Applications)로 작성되었으며, 입력자료 구축 모듈, 하도단면 입력 모듈, GZF 설정 모듈, GZF 평가 등의 4개 모듈로 구성되어 있다. 두 번째 연구과제는 구간분리 유무의 기준에 관한 연구로서 수위-유량관계곡선의 신뢰도에 직접적인 영향을 미친다. 본 연구에서는 일차적으로 단면의 특성이 상이한 4개의 수위관측소를 선정하여 수위-면적 곡선과 수위-면적변화량곡선을 생성하였으며 이로부터 단면변화와 구간분리의 특성을 분석하였다. 구간분리의 기준에 영향을 미치는 변수로는 단면특성인자, 유속, 하상경사, 수면경사, 단면통제, 하도통제 등을 들 수 있으며, 또한 다음과 같은 주요변수들이 서로 복합적으로 작용되기 때문에 일정한 기준을 제시하기란 어려운 부분이라 할 수 있다. 따라서 본 연구에서는 구간분리에 영향을 미치는 주요 변수 중에서도 가장 크게 영향을 주는 변수인 하도 단면의 특성 등을 중심으로 연구를 진행하였다. 먼저 단면의 특성이 서로 상이한 수위 관측소 단면을 선정하여 수위관측소별로 저수부에서 고수위 구간까지 10cm의 등간격으로 수위별 면적을 산정하여 구간분리의 가능성을 판단하였다. 구간분리의 유무에 관한 연구는 현재 진행 중에 있으며, 향후에는 1단면, 2단면, 3단면까지 파악하여 단면 특성이 구간분리에 미치는 영향 등을 파악할 계획에 있다. 또한 하도 단면의 다양성을 고려하여 단면형상이 상이한 여러 수위관측소 지점에서 구간분리의 기준을 연구할 계획이며, 단면의 특성을 파악한 후에는 유량, 유속, 하상경사, 하도통제 등을 고려할 계획이다.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.4
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• pp.222-226
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• 2011

This study was conducted to identify the characteristics of analytical errors shown in the Korean quality control program on bulk asbestos analyses using polarized light microscopy (PLM). 179 participating laboratories were required to analyze 4 samples respectively and asked to classify each test sample as asbestos-containing (positive) or non-asbestos-containing (negative). For positive samples, participants were also asked to identify the type and semiquantitate the contents of asbestos present. The test results showed 21 (4%) false negative errors among 562 samples, 9 (6%) false positive errors among 154 samples and 53 (9%) asbestos identification errors among 562 samples. Most of false negative and positive errors were observed in a few types of samples. Higher frequencies of asbestos identification errors were shown in samples containing two or more types of asbestos and samples containing anthophyllite, tremolite or actinolite asbestos. For semiquantitative analyses, the ratios of mean to nominal weight contents were 2.1 for chrysotile and 2.9 for amphiboles. A tendency of over-estimation was observed in semiquantitative analyses using the visual estimation technique and higher in case of analyzing samples containing amphiboles than chrysotile. Coefficients of variation (CVs) of semiquantitative analytical results were 0.44~0.83 and 0.5~1.14 for samples containing chrysotile and amphibole asbestos, respectively.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.429-432
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• 2005

LMTT(Linear Motor based Transfer Technology) is a new type of transfer system used in the maritime container terminal for the port automation, and largely consists of a controller, shuttle car, and rail. The shuttle car is divided into the frame part, the driving part, and wheels. In order to design this system, various researched on each part of it must be conducted. In this study, we dealt with the optimum design for the frame part of the shuttle car designed from previous studies on the strength of the frame with respect to the number of cross beams to minimize the weight of the shuttle car and to satisfy design criteria of cargo-handling systems in container terminal. For the optimization of the frame, thicknesses of each beam were adopted as design variables, the weight of the frame as objective function, and stress and deflection per unit length as constraint conditions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.385-390
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• 2005

LMTT (Linear Motor-based Transfer Techn-ology) is a horizontal transfer system for the yard automation, which has been proposed to take the place of AGV (Automated Guided Vehicle) in the maritime container terminal. The system is based on PLMSL (Permanent Magnetic Linear Synchronous Motor) that consists of stator modules on the rail and shuttle car. It is desirable to reduce the weight of LMTT in order to control the electronic devices with minimum energy. In this research, the DACE modeling, known as the one of Kriging interpolation, is introduced to obtain the surrogate approximation model of the structural responses. Then, the GRG(Generalized Reduced Gradient) method built in Excel is adopted to determine the optimum. The objective function is set up as weight. On the contrary, the design variables are considered as transverse, longitudinal and wheel beam's thicknesses, and the constraints are the maximum stresses generated by four loading conditions.

• Toxicological Research
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• v.18 no.2
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• pp.129-138
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• 2002

The mouse lymphoma assay (MLA) has been recently validated as a sensitive and specific test system to determine the genotoxic potential for a chemical. The objective of this study is to evaluate the utility of MLA for detecting mutagens. Especially, to compare MLA with the in vitro chromosomal aberration test (CA), we performed MLA using the microwell method with three chemicals (hydroxyurea, theophylline and amino acid copper complex), which were reportedly positive in the CA. In cell treated with hydroxyurea, anti-neoplastic agent that blocks DNA replication, evidence of a positive response was obtained without S9 mix for 4 h and 24 h. In addition, analysis of colony size distribution at concentration that gave an elevated mutant fraction showed that hydroxyurea induced a high proportion of small type colonies, indicating that hydroxyurea-induced mutation is associated with large chromosomal deletion. Conversely, negative MLA result was obtained for theophylline, which was wed as central nervous system stimulator. Although theophylline increased the mutant frequency at concentration of 1250 $\mu\textrm{g}$/$\textrm{m}{\ell}$ with S9 mix for 4 h, a concentration-related increase in mutant frequency was not observed. The MLA result of amino acid copper complex was considered equivocal because the positive result was obtained at concentration showing 10% or less RS or RTG. Thus, among 3 CA-positive chemicals, positive MLA result was obtained for one. The other two chemicals were negative and equivocal. However MLA, which evaluates mutagenic potential of chemicals through colony formation by cell grouth, may provide a higher predictivity of carcinogenesis than CA.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.5
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• pp.685-691
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• 2013

A load-cell-type anemovane operates based on wind vector properties. The developed load-cell-type anemovane is of a fixed type in which the wing does not rotate, unlike in the case of existing anemovanes. The load-cell-type anemovane is required to accurately derive the correlation between the load ratio and the wind direction in order to develop a qualified product. This is because the load ratio repeats every $90^{\circ}$ owing to the use of four load cells, and its value varies nonlinearly according to the wind direction. In this study, we compared analytical results with experimental results. Fluid analysis was carried out using ANSYS CFX. Furthermore, the prototype was tested using a self-manufactured wind tunnel. The wind direction was selected as the design variable. 13 selected wind direction conditions ranging from $0^{\circ}$ to $90^{\circ}$ with an interval of $7.5^{\circ}$ for analysis were defined. Furthermore, 10 wind direction conditions with an interval of $10^{\circ}$ for the experiment were defined. We derived the relations between the pressure ratio and the wind direction through the experiment and fluid analysis.

• Food Science and Biotechnology
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• v.15 no.2
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• pp.270-276
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• 2006

We evaluated the effects of extracts of Tsunokaori tangor peel on lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin $E_2\;(PGE_2)$ in RAW 264.7 cells. The ethyl acetate fraction of Tsunokaori tangor peel (EA-TTP) markedly inhibited the production of NO and $PGE_2$ in LPS-stimulated RAW 264.7 cells. Consistent with these findings, the expression levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins were down-regulated in a dose-dependent manner. Additionally, EA-TTP decreased the expression iNOS mRNA but not COX-2 mRNA. To determine the upstream signaling mechanism for the down-regulation of LPS-induced iNOS expression, we investigated the effect of EA-TTP on the degradation and re-synthesis of $I{\kappa}B{\alpha}$. EA-TTP dose-dependently delayed $I{\kappa}B{\alpha}$ degradation and increased $I{\kappa}B{\alpha}$ re-appearance following degradation, suggesting this as the mechanism by which EA-TTP suppressed iNOS gene expression. The EA-TTP also dose-dependently reduced the expression of the cellular stress-response protein heme oxygenase-1, and inhibited the LPS-induced sustained activation of extracellar signal-regulated kinase (ERK).

• The Journal of Society for e-Business Studies
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• v.15 no.3
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• pp.85-98
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• 2010

The prevailing infrastructure of ubiquitous computing paradigm on the one hand making significant development for integrating technology in the daily life but on the other hand raising concerns for privacy and confidentiality. This research presents a new privacy-preserving spatio-temporal query processing technique, in which location based services (LBS) can be serviced without revealing specific locations of private users. Existing location cloaking techniques are based on a grid-based structures such as a Quad-tree and a multi-layered grid. Grid-based approaches can suffer a deterioration of the quality in query results since they are based on pre-defined size of grids which cannot be adapted for variations of data distributions. Instead of using a grid, we propose a location-cloaking algorithm which uses the R-tree, a widely adopted spatio-temporal index structure. The proposed algorithm uses the MBRs of leaf nodes as the cloaked locations of users, since each leaf node guarantees having not less than a certain number of objects. Experimental results show the superiority of the proposed method.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.5
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• pp.1088-1101
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• 2013

The purpose of this study is to investigate intrinsic values with respect to the nature of aim from the viewpoint of Dewey. The intrinsic values have been recognized as values independent of activities or the content that preexist before embodied into activities. But from the perspective of Dewey, intrinsic values can be revealed only through the activity. Because they are inherent in the activities. Dewey suggested that the educational aim that is influenced by the traditional metaphysics should be meaningless in that it is given from outside and not related to human activities. The educational purpose that influenced by modern metaphysics and contemporary theories also can be regarded external, because the content and value of learning are assumed ahead activities. In the view of Dewey, the concepts of values are exposed through activities, so they can not exist independently. According to his own metaphysics that organism and its environment interact each other, all values c an be formed only in the course of activities. Thus, the intrinsic value of Dewey is a process per se, as the intrinsic value cannot be assumed ahead activities but can be exposed through activities. Bringing meaning to life through experience is Dewey's concept of growth as an educational aim. Education under such a purpose, would give the foundation to cultivate talent who are creative, proactive and communicate with their neighbors as a member of a democratic society.

• Physical Therapy Korea
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• v.15 no.3
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• pp.62-69
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• 2008

The purpose of this study was to measure intrarater and interrater reliability of a portable digital pressure algometer. Fifty healthy subjects were recruited for this study. Pressure pain thresholds of splenius capitis, levator scapular, and upper trapezius muscles were measured using by FPK algometer and portable digital pressure algometer. Three trials were done on each subject by two examiners. Intraclass correlation coefficients (ICCs) were used to determine the reliability of each measure. The intrarater reliability of the FPK algometer was good and excellent (ICC .63~.79) and the interrater reliability was poor and good (ICC .15~.57). The intrarater reliability of a portable digital pressure algometer was excellent (ICC .75~.86) and the interrater reliability was poor and good (ICC .35~.61). This result suggests that the intrarater reliability and interrater reliability of a portable digital pressure algometer were better than an FPK algometer.