• Corrosion Science and Technology
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• 제6권6호
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• pp.291-296
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• 2007

The corrosion of metals and alloys in flowing liquids can be classified into uniform corrosion and localized corrosion which may be categorized as follows. (1) Localized corrosion of the erosion-corrosion type: the protective oxide layer is assumed to be removed from the metal surface by shear stress or turbulence of the fluid flow. A macro-cell may be defined as a situation in which the bare surface is the macro-anode and the other surface covered with the oxide layer is the macro-cathode. (2) Localized corrosion of the differential flow-velocity corrosion type: at a location of lower fluid velocity, a thin and coarse oxide layer with poor protective qualities may be produced because of an insufficient supply of oxygen. A macro-cell may be defined as a situation in which this surface is the macro-anode and the other surface covered with a dense and stable oxide layer is the macro-cathode. (3) Localized corrosion of the active/passive-cell type: on a metal surface a macro-cell may be defined as a situation in which a part of it is in a passivation state and another in an active dissolution state. This situation may arise from differences in temperature as well as in the supply of the dissolved oxygen. Compared to uniform corrosion, localized corrosion tends to involve a higher wall thinning rate (corrosion rate) due to the macro-cell current as well as to the ratio of the surface area of the macro-anode to that of the macro-cathode, which may be rationalized using potential vs. current density diagrams. The three types of localized corrosion described above can be reproduced in a Jet-in-slit test by changing the flow direction of the test liquid and arranging environmental conditions in an appropriate manner.

• 대한가정학회지
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• 제39권2호
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• pp.131-146
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• 2001

The main purpose of this study, based on implicit personality theory and attribution theory, was to examine whether there exist the physical attractiveness stereotype, "what is beautiful is good," in the present Korea, and if exist, what is the content of it. The index of the physical attractiveness of this study was the facial attractiveness judged by 30 female university students. The appropriateness of clothing was manipulated by 4 types of clothing perceived appropriate for two assumed situations by female university students. Three female faces having high, medium, and low attractiveness were simulated with the same body dressed four types of clothing using CAD system, and a total of 12 stimulus persons were created. A total of 524 male and female(262 of male, 262 of female) university students from 3 universities in Kwangju, Korea were participated as subjects in this study. The design for the experiment was a 3$\times$4$\times$2 randomaized factorial, with three levels of facial attractiveness (high, medium, low), and four types attire(formal-masculine, formal-feminine, casual-masculine, casual-feminine), two kinds of context (job interview, dating) in which perceptions were occurred. The data were analysed using factor analysis, MANOVA, t-test and Duncan test. The results were as follows: 1. The facial attractiveness exerted significant positive effects on the evaluation of sociability, adjustment, and potency of her in both of two assumed situations (p<.001, respectively). 2. The appropriateness of stimulus person′s clothing had significant positive erect on the evaluation of sociability of stimulus person in dating context(p<.001). 3. The gender of subjects did not influenced the trait evaluations in both of two assumed situations.

• 한국항공우주학회지
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• 제45권10호
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• pp.825-835
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• 2017

본 논문에서는 단일 보의 최적 설계를 활용하여 드론 플랫폼을 구축하였다. 단일 보를 끝 단 질량을 가진 외팔보로 가정하였다. 수치 최적화 이론에 기초하여, ANSYS가 얻은 유사한 결과와 비교함으로써 새로운 설계의 검증 및 최적화를 수행 하였다. 마지막으로, 이 설계는 제어 시뮬레이션에 반영되며 공진 상황을 고려한 최적의 구조 설계 요구 사항을 만족함을 보였다.

• Asian-Australasian Journal of Animal Sciences
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• 제10권4호
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• pp.422-427
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• 1997

Breeding efficiency was investigated to reveal crucial factors for constructing effective breeding system with subdivided populations under equal genetic level. Simulation study of selection experiment was performed for 20 generations with 20 replications each, comparing average breeding values and inbreeding coefficients between the two breeding systems; single population scheme and two population scheme, each of which had the same genetic parameters. Genetic correlations (-0.5 to 0.5) were assumed to be caused only by pleiotropic effect of a gene. Phenotypes of the two traits generated by polygenic effect with additive 36 loci and residuals distributed normally were selected by two traits selection index procedure. Comparing between the single population scheme and the two population scheme, the single population scheme showed higher genetic gain with lower inbreeding coefficient. This result was confirmed particularly for the situation of high selection intensity, high heritability and high degree of unevenness for economic weight. Genetic correlations in the single population scheme were significantly lower than the two population scheme when initial genetic correlation was negative. When terminal crossbreeding for the two population scheme is taken into account, superiority of the two population scheme was suggested. The terminal crossbreeding was effective under the situation of long term selection, existence of moderate inbreeding depression and use of less extreme economic weight.

• 한국학교ㆍ지역보건교육학회지
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• 제17권2호
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• pp.31-44
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• 2016

Objectives: This study was aimed at finding out the current smoking situation of workers in the field of railroad electricity and vehicles and changes of their smoking behaviors after the raise of price of tobacco in 2015. Methods: With a self-administered questionnaire conducted from February 9 to March 6 2015, one-way ANOVA and crosstabs(PASW Statistics Ver. 18.0) were conducted on the data of 626 people. Results: As the result, the smoking rate was 39.1% and 90.5% of the smoking experienced group showed some changes including cutting down on smoking due to raise of price of tobacco. Factors related to smoking included stress, the number of times of drinking, awareness of harmfulness of smoking, the number of days with hard exercise per week and the marital status. Conclusion: Therefore, it is assumed that there is necessity of top-down intervention using these factors to cut down the smoking rate.

• 비교문화연구
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• 제37권
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• pp.361-382
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• 2014

This study aims to investigate the change of functions of duibuqi and analysis other fuctions of duibuqi apart from apology from pragmatics and conversation analysis perspectives. Duibuqi consists of dui(face) and buqi(be not capable of performing), and means 'be not capable of facing'. After that, it is assumed to have changed to 'ashamed' and finally 'sorry'. In terms of functions, duibuqi is generally regarded as meaning 'sorry' typically, so mei guanxi is considered to consist adjacency pair with it, but in this investigation, mei guanxi is very little adjacent to duibuqi contrary to expectation(n=2/28, per.=7.1/100). About half of duibuqi(n=15/28, per.=53.6/100) functions in apology action sequence, and in the sequence, duibuqi functions much more for take the lead in apology(n=11/15) but not for a reaction against scolding(n=4/15). And the other half of duibuqi(n=13/28, per.=46.4/100) functions for softening the impact of reject or direct action, or for switching situations, e.g. from favorable situation to unfavorable situation, or for expressing speaker's emotion to the other's repair etc. Consequently, duibuqi has being changed its meanings and its functions is being changed accordingly.

• 경영과학
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• 제32권4호
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• pp.109-133
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• 2015

This paper considers the allocation and engagement scheduling of air defense missiles by using MIP (mixed integer programming). Specifically, it focuses on developing a realistic MIP model for a real battle situation where multiple enemy missiles are headed toward valuable defended assets and there exist multiple air defense missiles to counteract the threats. In addition to the conventional objective such as the minimization of surviving target value, the maximization of total intercept altitude is introduced as a new objective. The intercept altitude of incoming missiles is important in order to minimize damages from debris of the intercepted missiles and moreover it can be critical if the enemy warhead contains an atomic or chemical bomb. The concept of so called the time window is used to model the engagement situation and a continuous time is assumed for flying times of the both missiles. Lastly, the model is extended to simulate the situation where the guidance radar, which guides a defense missile to its target, has the maximum guidance capacity. The initial mathematical model developed contains several non-linear constraints and a non-linear objective function. Hence, the linearization of those terms is performed before it is solved by a commercially available software. Then to thoroughly examine the MIP model, the model is empirically evaluated with several test problems. Specifically, the models with different objective functions are compared and several battle scenarios are generated to evaluate performance of the models including the extended one. The results indicate that the new model consistently presents better and more realistic results than the compared models.

• 한국가정과학회지
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• 제10권1호
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• pp.59-70
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• 2007

This study was conducted to investigate the perception about situation about school foodservice facilities and utilities in Chonbuk area. Self administered questionnaires were collected from 222 dietitians. Statistical data analysis was completed using a SPSS v. 10.0 program. The results are summarized as follows: Among 222 school foodservice systems, 68.5% of schools prepared the meal with conventional way and 31.5% of with commissary way. As the results of condition of school foodservice facilities, there was significantly differences between conventional and commissary foodservice systems; wall and ceilings(p<0.05), lighting(p<0.05), kitchen ventilation(p<0.05), preparation facilities(p<0.01), washstands(p<0.05), dressing rooms for employees(p<0.001), rest, and showers(p<0.01). On the basis those result it was assumed that the status of facilities of conventional foodservice systems better than commissary ones. About 66% of conventional foodservice systems and 34.5% of commissary ones have conducted own dining rooms. As to situation of dining rooms, conventional foodservice systems had better facilities than commissary ones. Therefore, governmental regulation agencies have to review and approval of plans prior to new construction or extensive remodeling of school foodservice facilities. In addition, content analysis was conducted regarding to dietitian's opinions on foodservice facilities and utilities.

• 한국국방경영분석학회지
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• 제11권2호
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• pp.6-14
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• 1985

The layered multi-barrier defense situation against penetrating enemy threat is analytically modeled towards minimizing the penetration probability. Each layer is characterized by probability of detection and probability of kill given detection. The two capabilities are assumed independent. Detection in a layer, however, affects detection performance in subsequent layers. The following three models were formulated and investigated: (1) 'Model A' permits increase of detection performance in only the next barrier, (2) 'Model B' permits the increase in all subsequent barriers linearly, and (3) 'Model C' expresses the increase in an asymptotic exponential way. The best and the worst barrier combinations are determined through model exercise and model performances are compared through sensitivity analysis for the 'intensification factor.'

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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• pp.89-96
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• 2005

Numerical procedure of design optimality evaluation is studied for caisson structural systems. Two kinds of evaluation methods can be considered; mathematical optimality criteria method (MOCM) and numerical optimization method (NOM). The choice of the method depends on the available information of the system MOCM can be used only when the information of all function values, gradients and Lagrange multipliers is available, which may not be realistic in practice. Therefore, in this study, NOMs are applied for the structural optimality evaluation, where only design variables are necessary. To this end, Metropolis genetic algorithm (MGA) is advantageously used and applied for a standard optimization model of caisson composite breakwater. In the numerical example, cost and constraint functions are assumed to be changed from the orignal design situation and their effects are evaluated for optimality. From the theoretical consideration and numerical experience, it is found that the proposed optimality evaluation procedure with MGA-based NOM is efficient and practically applicable.