• Journal of Astronomy and Space Sciences
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• v.21 no.2
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• pp.153-166
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• 2004

Interplanetary trajectories using the gravity assists are studied for future Korean interplanetary missions. Verifications of the developed softwares and results were performed by comparing data from ESA's Mars Express mission and previous results. Among the Jupiter exploration mission scenarios, multi-planet gravity assist mission to Jupiter (Earth-Mars-Earth-Jupiter Gravity Assist, EMEJGA trajectory) requires minimum launch energy ($C_3$) of 29.231 $Km^2$/$S^2$ with 4.6 years flight times. Others, such as direct mission and single-planet(Mars) gravity assist mission, requires launch energy ($C_3$) of 75.656 $Km^2$/$S^2$ with 2.98 years flight times and 63.590 $Km^2$/$S^2$ with 2.33 years flight times, respectively. These results show that the planetary gravity assists can reduce launch energy, while EMEJGA trajectory requires the longer flight time than the other missions.

• Korean Security Journal
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• no.39
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• pp.295-317
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• 2014

In advanced country, private investigation system is made up of private security and in domestic, there is growing need constantly to introduce private investigation but it is not passed until now in assembly so a messenger office which is run illegally is growing because of demand by subdividing business areas. That is a proof that both the police and private security don't meet demand of public peace to the public. that's why the police has own businesses like a investigation, traffic, intelligence, crime prevention and private security's business areas are limited like a facilities security, escort security, protection of a person, machine security, special security as the Private Security Act. This study attempts to know structural difference between private security system and private investigation system in case private investigation system becomes one of the private security. on some question, respondents reply like that private security and private investigation is very different(71.2%), different(22.4%), average(6.3%), similar(0.0%), very similar(0.0%). the result seems like respondents recognize private security and private investigation as different businesses. In the result of non-quantity analysis, the differences seem like a business character, expense, business scope, public power, scale of organization, object of threat, legislation. In domestic, effort to legislate private investigation system has undergone difficulty since congressman Ha Soon Bong's motion in 1999 and today, congressman Yoon Jae Ok's All Amendments Private Security Act and congressman Song Young Geun's Private Inveswtigation Act are pending in assembly. This study's result is intended for examining difference in exploration between private security and private investigation and then there is going to propose to the policy in case private investigation system is passed in assembly by amending Private Security Act like congressman Yoon Jea Ok's All Amendment Private Security Act.

• Korean Security Journal
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• no.39
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• pp.131-160
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• 2014

The radicalization of diaspora is a new phenomena that have been begun to emerge in the complex picture of terrorism. The existence of diaspora and its supports for violent terrorist activities have made the whole dynamic of terrorism more complicated and unpredictable. Therefore, this study attempts to understand the relationship between diaspora support and violent terrorist activities in the constellation of other significant correlates of violent terrorist activities discussed in the prior studies. In analyses, the author utilized a step wise regrssion analyses with a set of variable drawn from an emphatical data collected in Arab and Africa region. The data used in this study is called as "MAROB"(the Minorities at Risk Organizational Behavior), which is developed by START and Minority at Risk project and contains information terrorist groups in Middle-East and Africa region. Considering the significance of this new emergence of the link between diaspora and violent terrorist activities, and the challenging nature of conducting empirical studies on this topic, this study have great contributions on the development in the field of criminal justice as well as terrorism. Other contributions of this study, policy implications, and suggestions for future studies are further discussed in the discussion.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.1-12
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• 2016

The Harmony Search Algorithm (HSA) is one of the recently developed metaheuristic optimization algorithms. Since the development of HSA, it has been applied by many researchers from various fields. The increasing complexity of problems has created enormous challenges for the current technique, and improved techniques of optimization algorithms are required. In this study, to improve the HSA in terms of a structural setting, a new HSA that has structural characteristics, called the Multi-layered Harmony Search Algorithm (MLHSA) was proposed. In this new method, the structural characteristics were added to HSA to improve the exploration and exploitation capability. In addition, the MLHSA was applied to optimization problems, including unconstrained benchmark functions and water distribution system pipe diameter design problems to verify the efficiency and applicability of the proposed algorithm. The results revealed the strength of MLHSA and its competitiveness.

• Journal of Engineering Education Research
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• v.11 no.3
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• pp.12-23
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• 2008

The purpose of this study is to explore teaching and learning strategies through analyzing cases of foreign engineering education. With the analysis criteria composed of engineering education model, teaching and learning method, evaluation strategy, and technology supporting strategy, 10 foreign colleges of engineering in 5 countries were examined and analyzed. Teaching and learning strategies deduced from analysis state as follows. First of all, it need to develop engineering education models that reform should be made in systematic approach to teaching and learning, workplaces and laboratories, evaluation, technology support, etc. Secondly, the strategy for teaching and learning recommends supporting student directed learning, active learning participation, and collaboration learning by inductive learning strategies such as problem based learning, inquiry learning, project based learning, studio based learning, and blended learning. Thirdly, the evaluation strategy suggests that evaluation should be made to reflect students' learning and facilitate continuous learning based current learning results while it is necessary to build up a whole evaluation system. Finally, it is the educational technology approach for systematic engineering education that is required considering that many foreign colleges of engineering have reformed engineering education through technology supporting systems and are maximizing research and education in connection with other universities. This study is expected to contribute as preliminary data in developing further teaching and learning models and strategies for nurturing engineering students.

• Culinary science and hospitality research
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• v.18 no.4
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• pp.1-14
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• 2012

The focus of this study is on investigating an appropriate selling strategy for the guests of a fine dining restaurant in deluxe hotels located on seoul. As survey methods, questionnaires were prepared and distributed to the customers who visited the restaurants of five-star hotels in Seoul. The survey was carried out from July 1 to August 30, 2010. Total 223 copies of questionnaire were used for final analysis. Frequency analysis, descriptive statistics, exploration factor analysis, and reliability analysis were conducted through SPSS 18.0 for final analysis, and path analysis was conducted through AMOS 18.0 for verification of hypotheses. The hypothesized relationships among the models were tested simultaneously by using a structure equation model(SEM). The proposed model provided an adequate fit to the date, $X^2$ = 143.934(df=120, p<.001), GFI=0.935. AGFI= 0.907, RMR=0.022, CFI=0.983. The study results are as follows. First, the restaurant employee's adaptive selling strategies consist of persuasion-suggestion, kindness-rapidity. Second, in the result of analysis to understand the influences between customer satisfaction and adaptive selling strategies, customer satisfaction is shown to have an influential relationships with persuasion-suggestion strategy and kindness-rapidity strategy of employee's adaptive selling. Third, all adaptive selling strategies did not affect customer loyalty. Finally, customers who are satisfied with such services have a significant effect on customer loyalty and supports the existing previous studies.

• The Korean Journal of Air & Space Law and Policy
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• v.30 no.2
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• pp.155-176
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• 2015

Leasing is one of the main methods for Chinese airlines to introduce aircraft from overseas manufactures, and this method has been used for more than 30 years by Chinese airlines. Aircraft leasing in essence is a kind of financial transaction, through which lessors provide finance to lessees by means of the delivery of possession of the leased aircraft. At the time when China started to introduce aircraft through leasing some 30 years ago, the Chinese domestic laws were very insufficient to regulate these activities. Therefore, a construction process for the law of aircraft leasing was triggered then, and some fruit has been gained. By far, there are rules to adjust the aircraft activities in the aspects of contract, real right, default and bankruptcy remedies. However, as the improvement of any system must undergo a process of exploration, the law of aircraft leasing in China is still faced up with many challenges. Especially with the emergence and prosperous of domestic leasing industry, new transaction structures and models of aircraft leasing have emerged, which leaves new challenges to current legal system. On the basis of introducing the history and main contents of Chinese legal regime of aircraft leasing, this paper offers an analysis of achievements and challenges on present Chinese laws in the aspects of contract, real right and remedies.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.3
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• pp.245-253
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• 2001

To investigate the effects of hydromechanical and textural characteristics of sediment deposits on the cultivation of Manila clam, Ruditapes philippinarum surface and sub-surface core sediments were collected seasonally in Gomso tidal flat. Grain size distribution were analyzed to investigate the annual variation of sediment texture. In winter unimodal distribution of grain size with the peak at $5\phi$ is dominant However, during the summer sediment texture become a little bit coarser and grain size distribution shows the peaks at $4\~5 \phi$. Optimum sediment texture for the cultivation of manila clam, R. philippinarum was found to be sandy silt in which mean Brain size was between 4 and $5 \phi$ with the sand content less than $50\%$ and clay content of $5\~10\%$. Mechanical and hydrological characteristics of sediment deposits were also studied in the laboratory and the results were applied to the numerical simulation for the behavior of surface sediment subjected to the cyclic loading from sea-water level change. Results of numerical simulation illustrate that the permeability of sediment had to be maintained in the range of $10^{-11}\sim10^{-12}m^2$ to ensure the proper sedimentological environment for the cultivation of manila clam, R. philippinarum. The deposits of virtually impermeable mud layer, with the threshold thickness of 4 cm, would be very hazardous to clam habitat.

• Culinary science and hospitality research
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• v.21 no.5
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• pp.14-24
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• 2015

Fast food restaurants are one of the fastest growing industries in the world. Even though it is an emerging field, there are few studies about the relationship of fast food customer satisfaction about brand value and behavior intention. The current study examined which factor concerning brand value affects to customer satisfaction in fast food restaurants and investigated how customer satisfaction affects the behavior intention. The subjects of this study are current undergraduate students in Busan, South Korea. A self-administrated questionnaire survey was distributed to 528 students who have been to fast-food restaurants in Busan, Korea and 493 questionnaires were used for data analysis. Research findings indicated that food quality, brand image, brand awareness, and brand association through multiple linear regression were significant factors for customer satisfaction. In addition, the result of a simple linear regression showed that customer satisfaction was positively related to behavior intention. This study can provide valuable information and offer specific ways for fast food managers to increase customer satisfaction and behavior intention.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.48-54
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• 2004

The effects of injector spacing s and injector diameter d on mixing are numerically investigated in supersonic combustor with perpendicular injection behind a backward-facing step. Simulations are reported for airstream Mach number of 2.4. Parameters are changed on following 4 cases to investigate the effects of injector configuration on mixing efficiency $\eta_m$. In the case of varying d or s, dynamic pressure ratio $Rq(=(pu^2)_j/(pu^2)_a)$ is also varied to keep bulk equivalence ratio $\Phi({\oe})Rq.d^2/s)$ constant. (l) Injector spacing s is varied at constant $\Phi$=0.5, 1, 2 for injector diameter d=6mm. In the case of $\Phi$=1, $\eta_m$ has its maximum value at s=24mm. The reason is that increase of $\eta_m$. , by widening spacing at Rq=constant competes with decrease of $\eta_m$ by increasing Rq at s=constant. When spacing is narrow, the flow field of vicinity of injector becomes two-dimensional because adjacent jets interferes each other. By widening spacing, air is easily entrained by three-dimensional effect. This mechanism also appears in the case of $\Phi$=0.5, 2 for d=6mm, and $\eta_m$. reaches its maximum value at s=24mm for $\Phi$=0.5 and at s=42mm for $\Phi$=2. (2) In the case of injector diameter d varied at $\Phi$=1 for s=30mm, $\eta_m$. has its maximum value at d=3mm. The reason is that decrease of $\eta_m$ by increasing injector diameter competes with increase of $\eta_m$ by decreasing Rq at d=constant.(3) In the case of s varied at $\Phi$=0.5, 1,2 for d=3mm, the injector spacing at which mixing efficiency has its maximum value is s= 18mm for $\Phi$=0.5, s=24mm for $\Phi$=1, s=24mm for $\Phi$=2. Therefore it is found that d=3mm and s=24mm can be optimum configuration over a range of $\Phi$=0.5~2.(4) The effect of h on the optimum spacing is investigated. s is varied for d=6mm at step height h=4, 6, 8mm. The simulation results do not show significant change on the step height.