• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.9
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• pp.667-674
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• 2014

A ship's propulsion shafting system is subjected to varying magnitudes of intermittent loadings that pose great risks such as failure. Consequently, the dynamic characteristic of a propulsion shafting system must be designed to withstand the resonance that occurs during operation. This resonance results from hydrodynamic interaction between the propeller and fluid. For ice-class vessels, this interaction takes place between the propeller and ice. Producing load- and resonance-induced stresses, the propeller-ice interaction is the primary source of excitation, making it a major focus in the design requirements of propulsion shafting systems. This paper examines the transient torsional vibration response of the propulsion shafting system of an ice-class research vessel. The propulsion train is composed of an electric motor, flexible coupling, spherical gears, and a propeller configuration. In this paper, the theoretical analysis of transient torsional vibration and propeller-ice interaction loading is first discussed, followed by an explanation of the actual transient torsional vibration measurements. Measurement data for the analysis were compared with an applied estimation factor for the propulsion shafting design torque limit, and they were evaluated using an existing international standard. Addressing the transient torsional vibration of a propulsion shafting system with an electric motor, this paper also illustrates the influence of flexible coupling stiffness design on resulting resonance. Lastly, the paper concludes with a proposal to further study the existence of negative torque on a gear train and its overall effect on propulsion shafting systems.

• Journal of Sericultural and Entomological Science
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• v.53 no.1
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• pp.50-54
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• 2015

Mulberry fruit is common to keep a frozen storage because of the very high water content. Because freezing-storing cost is generated before the processing or sales, farmers of mulberry fruit production are weighted in financial burden. In addition, mulberry fruit has difficulty in expanding consumption by made in the simple processed products like the mulberry jam, mulberry juice, mulberry enzyme, alcohol, etc. Recent, frozen fruits including frozen blueberries, frozen strawberries, frozen mango, frozen rich, frozen mulberry fruit has been started to sell in the large discount stores and convenience stores. However, there is restricted sales in only special place that have the frozen distribution facilities. So, for the income improvement and consumption promotion of mulberry farmers facing these difficult situations, we developed the processing method of semi-dried mulberry fruit using the vacuum freezing dryer. The frozen mulberry fruit which was stored below $-40^{\circ}C$ is to dry in a vacuum freeze dryer, at $30{\sim}35^{\circ}C$, 23 ~ 24 hours. Semi-dried mulberry fruit seperated respectively. It had soft texture, and maintained shape, size and flavor. In particular, semi-dried mulberry fruit can be stored at room temperature.

• Journal of Korean Society of Transportation
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• v.19 no.5
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• pp.119-134
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• 2001

This paper proposed a dynamic transit vehicle simulation model and a dynamic transit passengers simulation model, which can simultaneously simulate the transit vehicles and passengers traveling on a transit network, and also developed an algorithm of dynamic departure time choice model based on individual passenger. The proposed model assumes that each passenger's behavior is heterogeneous based on stochastic process by relaxing the assumption of homogeneity among passengers and travelers have imperfect information and bounded rationality to more actually represent and to simulate each passenger's behavior. The proposed model integrated a inference and preference reforming procedure into the learning and decision making process in order to describe and to analyze the departure time choices of transit passengers. To analyze and evaluate the model an example transit line heading for work place was used. Numerical results indicated that in the model based on heterogeneous passengers the travelers' preference influenced more seriously on the departure time choice behavior, while in the model based on homogeneous passengers it does not. The results based on homogeneous passengers seemed to be unrealistic in the view of rational behavior. These results imply that the aggregated travel demand models such as the traditional network assignment models based on user equilibrium, assuming perfect information on the network, homogeneity and rationality, might be different from the real dynamic travel demand patterns occurred on actual network.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.3
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• pp.141-147
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• 2018

In a time when product development cycles are getting shorter and shorter, many companies are making efforts to develop products with high reliability in a short period of time, accelerated life test is widely used as a method to quickly evaluate reliability. Accelerated life test reduces the test life or the life of the product from the observed data by shortening the lifetime of the product or abruptly lowering the performance under the worse condition than the actual condition in order to shorten the test cost or the test time. In this paper, BL3640A-06P+RB35, DC12V model, which is used in the support device of an automatic rotation type digital signage, which display various information such as textures and images on a display screen in a public place or a commercial space, BLDC motors were subjected to a constant stress test and at the rotational speed of 1rpm, $180^{\circ}$ rotation and reverse rotation under actual use conditions, the stress was imposed on the rotating speed of 2rpm and the weight of the actual installed product from 22.2kgf to 10kgf were installed. The lifetime of the actual use environment condition is 23,545 hours and the rotation speed is accelerated. The life time of the acceleration condition with the additional weight is 1,380 hours. The acceleration factor is calculated as 17.06, the one year guarantee test day is 235 days to 14 days, of the period from 470 days to 28 days, and the third year from 704 days to 42 days. The test date of the BLDC motor was tested on the shortened test date, and the rotational speed and the current value were measured. It is found that there is no defect even if it operates as the test date corresponding to the specified one year warranty period and the 3 year accelerated life test which is experimented. Using the statistical technique of the regression analysis the expected time for the motor to defect to #4 samples was 20 years.

• The Journal of the Korea Contents Association
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• v.13 no.3
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• pp.141-151
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• 2013

With the spread of Personal Computers(PC) in the 1980's, many people started to deal businesses with PC. From late 1990's, the Internet age with PC have started and many people have showed keen interest in cyber-space and now they are utilizing it. Since 2000's the use of cyber-space have skyrocketed and it caused significant changes to humans' life. There was a huge prosperity to us but the new kind of crime, cyber-crime, was raised. Unlike past physical type of crimes, those cyber-crimes take place in the cyber-space and they have special features of non-facing, anonymity, specialty, technologic, repetition, continuation. Those cyber-crimes are continually growing since 2003 and in 2010 it almost doubled compared to 2003. General cyber-crimes like phishing-scam pornography circulation was most of them and notably perpetrators of them are younger generation. Recently cyber-crimes are showing the trend of advancing more and more and cyber-bullying, fraud like phishing scam are on the rise. The police are responding by making 'Cyber Terror Response Center', but it does not work effectively with the problems of breakup of prevention and investigation unit, procedure of investigation and the system itself. So, I suggest practical use of private security to remedy our police's weakness and to prevent cyber-crimes. Preventing solutions of cyber-crime with private security are physical defense of large-scale servers and vital computers, building of Back-up system to prevent vital data loss, and building of cyber-crime preventing system combining software and hardware.

• Environmental and Resource Economics Review
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• v.15 no.4
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• pp.761-782
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• 2006

Public concern about potential environmental risks of agricultural business for the livestock production and processing is increasing. However, due to differences in general industry structural characteristics, such as farm production and waste management practices, the effect of environmental policies may differ from species to species as well as across size categories. I hypothesize that additionally the Hog subsector may be more responsive to (or a greater driver of) a changing environmental policy environment than the beef cattle subsector. As a result, I expect to see more evidence of sensitivity in the environmental policy milieu from hog-operation stocking and location decisions than with the beef cattle industry. The written stringency may not effective, instead state's willingness to enforce has directed and regulated. However, in presence of rapid structural change, just like hog, industry location is affected by state regulation. The environmental compliance cost may be a small portion of industry total cost and fixed cost of beef industry makes for them to take into account environmental compliance for their decision location making. The special movements of flog industry have chance to minimize the cost of the operation and they willing to locate less stringent place.

• The Journal of the Korea Contents Association
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• v.9 no.8
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• pp.285-293
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• 2009

The purpose of this study is to closely examine the effect of exercise behavior change of casino securities on their Self-efficacy. This observation takes place in casino enterprises in the whole country. Within these areas, we set the selected employees as the targeted sampling unit, we extracted the specimen, using the stratified cluster random sampling with the quota sampling, putting a weigh on the specimen of focused areas. Among 420 persons sampling unit, we have excluded 47 copied which seem to be insincere, and actually used 373 copies in this study. Evaluation forms are used as a study method; each form consists of continuance 5 points Likert scales and nominal/proportional scaling and used after excluding a test through the analysis of validity and reliability. After encoding and inputting the framing completed data along with each purpose, it was computerized by computer process, making use of SPSS 15.0 version. Through the data analysis according to these methods and procedures, the result on this study is described below. First, the exercise behavior change process the self-efficacy according to socio-demographic characteristics make a difference. Second, the self-efficacy according to socio-demographic characteristics make a difference. Third, the exercise behavior change process influence on the self-efficacy.

• The Journal of Industrial Distribution & Business
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• v.9 no.3
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• pp.89-98
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• 2018

Purpose - Despite the global economic crisis, the numbers of coffee shops used for providing a place for social and cultural interactions show an upward trend and have become an indispensable part in people's daily life in recent years. Under the circumstance of tremendous efforts of searching new management strategies and projects, the concept of servicescape(which has physical environment characteristics) may provide a better alternative. Therefore, the purpose of this study can be broadly divided into 3 key points. First is to investigate the effects of servicescape on customer satisfaction, service value and customer loyalty about Coffee Shops in Jeonju area. Second is to examine the mediating effect of customer satisfaction and service value between servicescape and customer loyalty. Third, there is evidence that indicates the moderating effect among the interaction of customer and staff, brand image and the composition of servicescape, customer satisfaction, service value and customer loyalty. Research design, data, and methodology - This study begins empirical research about users of coffee shops' services. The data of the study is collected from 285 samples of a questionnaire which has been made from Korea and analysed by IBM SPSS 24.0 and IBM AMOS 24.0. Results - The results are reported below: First of all, the composition of condition, functionality, cleanliness and aesthetic characteristics of the servicescape has a significant impact on customer satisfaction and service value. Furthermore, customer satisfaction is identified as a factor to influence service value. Moreover, customer satisfaction and service value are identified as the causal relationship with customer loyalty. Besides, customer satisfaction and service value illustrated the mediation effect between the composition of servicescape and customer loyalty. Finally, the interaction between customer and staff, brand image illustrates the moderated effect. Conclusions - The composition of servicescape contributes to the formation of customer satisfaction and enhancing the customer's perceived service value in coffee shops. By meeting diverse and complex needs of consumers in coffee shop, the service value will not only attract loyal customers, but also increase customer loyalty and profitability. In a word, managers should rely on servicescape to enhance service experience by making differences with other competitors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.3085-3093
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• 2012

The purpose of this study is to examine difference in knowledge level, attitude and performance competence on CPR (Cardiopulmonary Resuscitation) in football players. For this, questionnaire survey was carried out from October 5, 2011 to October 19 targeting 234 football players of high schools and universities where are located in Seoul, Gyeonggi, and Gangwon-do Province. The collected data was carried out frequency, t-test ANOVA, and correlation analysis by using SPSS/PC 19.0 for Windows. All the statistical analyses were set for significance level in p<.05. The results are as follows. Knowledge level, attitude and performance competence on CPR according to football players' general characteristics were indicated to have influence upon gender, academic background, and the appearance of educational experience in CPR. It was indicated that there is difference between CPR-related characteristics, and knowledge level, attitude & performance competence. Also, it was indicated that there is correlation among knowledge level, attitude and performance competence on CPR in football players. Based on these results, it accurately grasps experience and knowledge level on CPR in football players, thereby making a place available for having a game with security, resulting in being considered to possibly make the better sports.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.709-719
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• 2010

As the world has had a high recognition of security since 9/11 attacks in 2001, many countries and international organizations around the world are making strenuous efforts in establishing stronger security, centering on areas with high possibility of terrorist attacks. In particular, harbor facilities where a great deal of trade take place between countries, have high possibilities of becoming the objects of terrorist attacks and also of becoming places of trading objects and illegal items which might be leveraged for terror attacks. In this study, I have explained the current status of the harbor entrance system through existing documents, interviews and field trips to harbors and have also introduced improvement measures using RFID technology from the viewpoint of BP(Business Process). I expect that this study will be used as basic materials because I have studied the number of people entering harbors and working procedures for vehicle entrance, which have not been studied so far and also laid out various factors to be considered to introduce RFID technology.