• Journal of Advanced Marine Engineering and Technology
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• v.8 no.1
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• pp.17-36
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• 1984

Since 1973, the competition on the development of fuel saving type internal combustion engines has become severe by the two times oil shock, and new type engines are reported every several months. Whenever these new type engines are developed, new designs are required and they will be offered in the market after performing the endurance test for a long time. But the engine market is faced with a heavy burden of finance, as the developing of a new engine requires tremendous expenses. For this reason, the computer simulation method has been lately developed to cope with it. The computer simulation method can be available to perform the reasonable research works by the theoretical analysis before carrying out practical experiments. With these processes, the developing expenses are cut down and the period of development is curtailed. The object of this study is the development of simulation computer program for the small naturally aspirated four-stroke diesel engine which is intended to product by the original design of our country. The process of simulation is firstly investigated for the ideal engine cycle, and secondly for the real engine cycle. In the ideal engine cycle, each step of the cycle is simulated by the energy balance according to the first law of thermodynamics, and then the engine performance is calculated. In the real cycle imulation program, the injection rate, the preparation rate and the combustion rate of fuel and the heat transfer through the wall of combustion chamber are considered. In this case, the injection rate is supposed as constant through the crank angle interval of injection and the combustion rate is calculated by the Whitehouse-Way equation and the heat transfer is calculated by the Annand's equation. The simulated values are compared with measured values of the YANMAR NS90(C) engine and Mitsubishi 4D30 engine, and the following conclusions are drawn. 1. The heat loss by the exhaust gas is well agree with each other in the lower load, but the measured value is greater than the calculated value in the higher load. The maximum error rate is about 15% in the full load. 2. The calculated quantity of heat transfer to the cooling water is greater than the measured value. The maximum error rate is about 11.8%. 3. The mean effective pressure, the fuel consumption, the power and the torque are well agree with each other. The maximum error is occurred in the fuel consumption, and its error rate is about 7%. From the above remarks, it may be concluded that the prediction of the engine performance is possibly by using the developed program, although the program needs to reform by adding the simulation of intake and exhaust process and assumping more reliable mechanical efficiency, volumetric efficiency, preparation rate and combustion rate.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.8
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• pp.1120-1128
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• 2016

The objective of this work was to evaluate the effects of supplementation with nitrogen and starch on the nutritional performance of grazing cattle during the rainy season. Five rumen cannulated Nellore steers, averaging 211 kg of body weight (BW), were used. Animals grazed on five signal grass paddocks. Five treatments were evaluated: control (forage only), ruminal supplementation with nitrogen at 1 g of crude protein (CP)/kg BW, ruminal supplementation with starch at 2.5 g/kg BW, supplementation with nitrogen (1 g CP/kg BW) and starch (2.5 g/kg BW), and supplementation with nitrogen (1 g CP/kg BW) and a mixture of corn starch and nitrogenous compounds (2.5 g/kg BW), thereby resulting in an energy part of the supplement with 150 g CP/kg of dry matter (DM). This last treatment was considered an additional treatment. The experiment was carried out according to a $5{\times}5$ Latin square design following a $2{\times}2+1$ factorial arrangement (with or without nitrogen, with or without starch, and the additional treatment). Nitrogen supplementation did not affect (p>0.10) forage intake. Starch supplementation increased (p<0.10) total intake but did not affect (p<0.10) forage intake. There was an interaction between nitrogen and starch (p<0.10) for organic matter digestibility. Organic matter digestibility was increased only by supplying starch and nitrogen together. Nitrogen balance (NB) was increased (p<0.10) by the nitrogen supplementation as well as by starch supplementation. Despite this, even though a significant interaction was not observed (p>0.10), NB obtained with nitrogen plus starch supplementation was greater than NB obtained with either nitrogen or starch exclusive supplementation. Supplementation with starch and nitrogen to beef cattle grazing during the rainy season can possibly improve digestion and nitrogen retention in the animal.

• Journal of the Korea Concrete Institute
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• v.20 no.5
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• pp.653-660
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• 2008

The purpose of this study is to analyze the optimal mix design of the sound absorption material that is made from perlite and various binder systems for noise barrier wall. The polymer cement slurry which is made from two types of polymer dispersions, and silicone type inorganic material are used as binder. The test specimens are prepared with various polymer cement ratios, binder ratios, and tested for strengths, freezing and thawing and sound absorption performance by the tube and the reverberation room methods. From the test results, the difference of sound absorption coefficient by the tube method is a little recognized, however, noise reduction coefficient (NRC) of test specimens bound by the polymer cement slurry is in the ranges of 0.48 to 0.51. They are a little higher than those bound by cement only, and are lower values than recommended value of 0.7 by the Ministry of Environment. However, the sound absorption coefficient of test specimens at low frequency range of 250 to 500 Hz by reverberation room method shows very high values as 0.84 to 1.00, and 0.57 to 0.77 at the high frequency. The test specimens with polymer cement slurry binder have a good balance between performance and cost, and have proper properties in strengths, freezing and thawing resistance as sound absorption material for noise barrier wall. It is apparent that the good sound absorption material can be produced according to the optimum mix design that is recommended from this study.

• Journal of KIISE:Software and Applications
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• v.28 no.9
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• pp.669-680
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• 2001

Genetic Algorithms are optimization algorithm that mimics biological evolution to solve optimization problems. Genetic algorithms provide an alternative to traditional optimization techniques by using directed random searches to locate optimal solutions in complex fitness landscapes. Hybrid genetic algorithm that is combined with local search called learning can sustain the balance between exploration and exploitation. The genetic traits that each individual in the population learns through evolution are transferred back to the next generation, and when this learning is combined with genetic algorithm we can expect the improvement of the search speed. This paper proposes a genetic algorithm based Cellular Learning with accelerated learning capability for function optimization. Proposed Cellular Learning strategy is based on periodic and convergent behaviors in cellular automata, and on the theory of transmitting to offspring the knowledge and experience that organisms acquire in their lifetime. We compared the search efficiency of Cellular Learning strategy with those of Lamarckian and Baldwin Effect in hybrid genetic algorithm. We showed that the local improvement by cellular learning could enhance the global performance higher by evaluating their performance through the experiment of various test bed functions and also showed that proposed learning strategy could find out the better global optima than conventional method.

• The Journal of the Korea Contents Association
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• v.14 no.1
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• pp.128-138
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• 2014

Local festivals quite often give their visitors and local residents a good opportunity to experience the regional culture thoroughly. Also, the festivals empower the cultural pride and communal sociality, and create new jobs improving local economy. In Korea, more than 700 local festivals are held every year. Each festival is organized and operated upon all different purpose and mission. It is unfortunate, however, that many festivals fail to balance between making profits and accomplishing their purpose. Festival's marketing plan and content management should be cohesive, but at the same time, they also should be different depending on the festival's purpose and program. Especially in case of performance natured festivals, the role and function of festival directing should be more weighed on content management. Namhaean Byeolsingut is one of performance natured festivals, in which its archetype or primitive form is well maintained. This study observes the primitive form of NB from the director's viewpoint, and then provides a solid foundation on how those main characteristics of NB could be applied to invigorating local festival directing. The directing suggestions here are motivated by NB's ritual, performative, and play form.

• Journal of the Korean Operations Research and Management Science Society
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• v.32 no.2
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• pp.17-40
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• 2007

Most research on web site design has focused on technological factors, while visual aesthetic factors have been considered less important. In contrast, this study focuses on visual aesthetic factors in web site design. Findings of this study can be summarized as follows : (1) The result of SPSS-factor analysis shows that there are 3 distinct factors, 'classical aesthetics', 'expressive aesthetics', and 'usability' 'Classical aesthetics' and 'expressive aesthetics' can be described by visual aesthetic design, 'Visual aesthetic design' can be distinguished from 'usability'. This conceptual confusion relating to 'usability' and 'visual aesthetic design' can be clarified by these findings. (2) As a result of multiple regression analyses, 'classical aesthetics', 'expressive aesthetics', and 'usability' have a positive influence on 'interactivity' and 'web site evaluation'. This research clarifies the concepts of 'expectations' of Grier [18] and 'engagement' of Rosen and Purinton [33] as the 'interactivity' between users and web sites. Furthermore, this research suggests a valid model with high $R^2$(interactivity, 48% : web site evaluation, 68%). (3) Empirical tests show that the differences among users in 'entry point' are related to the characteristics of web sites and the personal characteristics of users. The differences among users in terms of 'scanning time' are closely related to the attitudes and evaluation tendencies of users with respect to web sites. These findings could contribute to the 'search phase' of the Faraday model [16], enabling it to be more precise and extensible. The managerial implication of this study is that customers' preferences regarding web site designs are differences, as their preferences are based on their individual characteristics. Therefore, marketing managers should consider promotional tools on web sites that are relevant to the target market. An optimal strategy for web design could be a carefully-selected combination of factors that are relevant to the 'interactivity' and 'evaluation' of web sites. Additionally, if marketing managers want to attract more favorable attitudes and more affirmative evaluations from users, web sites should be designed so that they are understood more quickly by users. finally, this study suggests that 'good design' for web sites depends on understanding how to attain the appropriate balance between 'classical aesthetics' and 'expressive aesthetics', based on the target customer.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.6
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• pp.43-54
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• 2018

The accurate estimation of reference crop evapotranspiration ($ET_o$) is essential in irrigation water management to assess the time-dependent status of crop water use and irrigation scheduling. The importance of $ET_o$ has resulted in many direct and indirect methods to approximate its value and include pan evaporation, meteorological-based estimations, lysimetry, soil moisture depletion, and soil water balance equations. Artificial neural networks (ANNs) have been intensively implemented for process-based hydrologic modeling due to their superior performance using nonlinear modeling, pattern recognition, and classification. This study adapted two well-known ANN algorithms, Backpropagation neural network (BPNN) and Generalized regression neural network (GRNN), to evaluate their capability to accurately predict $ET_o$ using daily meteorological data. All data were obtained from two automated weather stations (Chupungryeong and Jangsu) located in the Yeongdong-gun (2002-2017) and Jangsu-gun (1988-2017), respectively. Daily $ET_o$ was calculated using the Penman-Monteith equation as the benchmark method. These calculated values of $ET_o$ and corresponding meteorological data were separated into training, validation and test datasets. The performance of each ANN algorithm was evaluated against $ET_o$ calculated from the benchmark method and multiple linear regression (MLR) model. The overall results showed that the BPNN algorithm performed best followed by the MLR and GRNN in a statistical sense and this could contribute to provide valuable information to farmers, water managers and policy makers for effective agricultural water governance.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.6
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• pp.688-693
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• 2016

In this study, various conflicts in the maritime police organization were diagnosed and police subculture, which is different from dominant mainstream maritime police culture, was concluded to cause conflicts. In addition, maritime police conflicts and conflicts due to the balance, confrontation, and contradiction between bureaucratic and democratic values in the maritime police organization itself are discussed. The results of analysis on the effects of Maritime police subculture on organizational conflict are as follows: First, the influence of cynicism on functional conflict was explored. The higher the level of lies of the persons under investigation, the more functional conflict appeared. Also, if a person showed a low level of credibility among the police, this also led to functional conflict. In addition, if an individual showed low levels of cooperation and credibility with the police, this resulted in hierarchical conflict. Second, the influence of machismo on functional conflict was also explored. It was found that female officers experienced conflicts because of poorer job performance compared to male counterparts. In hierarchical issues, female officers experienced conflict over the reduced scope of tasks assigned to them and lower job performance ability. Third, the effect of non-acceptance of change in functional conflict was not statistically significant. An aggressive attitude toward crime control and rejecting jobs unrelated to crime influenced functional conflict, and an aggressive attitude and performing jobs unrelated to crime lead to functional conflict.

• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.807-815
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• 2018

This study was investigated the effect of dietary probiotic mixture on blood biomarkers, immune responses, caecal microorganism and productivity in broiler chickens under heat stress (HS). A total of 400 broiler chick males (Ross 308) were divided into four groups of 100 heads each, group C (control, room temperature $25^{\circ}C$), HS (heat stress $33^{\circ}C$) and HSP (HS plus probiotic mixture 500, 750 mg/kg of diet), respectively. Broiler body weight gain, feed intake, feed conversion ratio and immune organ weight increased in the HSP group compared to the HS group. The concentrations of blood IgG and lymphocyte were increased in the HSP group compared to the HS group, and the heterophil:lymphocyte (H:L) ratio, corticosterone concentration and mortality were low. Lactobacillus in the cecum increased in the HSP group compared to the HS group, but was lower in Escherichiacoli (E. coli), coliform bacteria and aerobic bacteria. These results indicate that feeding probitic mixture including three strains such as B. subtilis, S. galilaeus and Sphingobacteriaceae to broiler exposed to heat stress can improve production with lowering mortality by improving immune response and microbial balance.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.3
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• pp.456-464
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• 2020

Objective: The aim of this study is to investigate the effect of oral spray with probiotics on the intestinal development and microflora colonization of hatched ducklings. Methods: In Exp. 1, an one-way factorial design was used to study the antibacterial activity of the probiotics and metabolites on Escherichia coli (E. coli) without antimicrobial resistance. There were four experimental groups including saline as control and Lactobacillus, Bacillus subtilis, combined Lactobacillus and Bacillus subtilis groups. In Exp. 2, 64-day-old ducklings were allotted to 2 treatments with 4 replicated pens. Birds in the control group were fed a basal diet supplemented with Lactobacillus fermentation in the feed whereas birds in the oral spray group were fed the basal diet and administrated Lactobacillus fermentation by oral spray way during the first week. Results: In Exp. 1, the antibacterial activities of probiotics and metabolites on E. coli were determined by the diameter of inhibition zone in order: Lactobacillus>combined Lactobacillus and Bacillus subtilis>Bacillus subtilis. Additionally, compared to E. coli without resistance, E. coli with resistance showed a smaller diameter of inhibition zones. In Exp. 2, compared to control feeding group, oral spray group increased (p<0.05) the final body weight at d 21 and average daily gain for d 1-21 and the absolute weight of the jejunum, ileum and total intestine tract as well as cecum Lactobacillus amount at d 21. Conclusion: Lactobacillus exhibited a lower antibacterial activity on E. coli with resistance than E. coli without resistance. Oral spray with Lactobacillus fermentation during the first week of could improve the intestinal development, morphological structure, and microbial balance to promote growth performance of ducklings from hatch to 21 d of age.