• Journal of Korea Port Economic Association
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• v.34 no.4
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• pp.17-38
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• 2018

The purpose of this study is to establish shipping companies' selection factors related to a classification society and to explore the relative importance of each factor using the analytical hierarchy process(AHP) technique. Insufficient research exists on the hierarchial structure of shipping companies' factors of selecting a classification society. The factors are identified and classified into two tiers of major and detailed factors, by referring to the related industrial linkages, prior research related to the determinants, and the process and service delivery of the classification society's activities. The empirical analysis of this study is based on the relative importance of determinants when selecting a classification society, and experts engaged with shipping companies were surveyed using questionnaires. The results of the AHP methodology on the main factors of shipping companies in selecting a classification society are as follows. The relative importance of the main factors was 0.373 for technical and survey services, 0.284 for recognized organizations(RO) functions, 0.177 for cost and 0.167 for market(related industry) expectations. The relative importance of the detailed factors is 0.144 for the ability to respond to a port state control(PSC) inspection, 0.143 for technical services, 0.090 for the requirements of financial institutions/ shippers/shipyards, 0.087 for class maintenance costs, 0.086 for the survey network, 0.085 for surveyor competency, 0.072 for cooperation with IMO and government authorities, 0.067 for recognition for RO, 0.058 for the business power of the classification society, 0.052 for the initial inspection costs, 0.040 for reputation and trustworthiness, 0.038 for the costs related to the class, and 0.037 for connections to related industries.

• Journal of the Korea Society for Simulation
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• v.26 no.3
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• pp.115-123
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• 2017

Dispite the fact that our military has outwardly made notable accomplishments such as the development of weapon systems like tanks, self-propelled artillery, and missiles, there has been a lack of attention to producing weapon effectiveness data that suggests a standard as to what effects the developed weapons will demonstrate on the battlefield. For such reasons, most of the weapon effectiveness data utilizes JMEM data introduced by the United States and as for the rest of the data that cannot be acquired, respective branches create and utilize their own data through research. This research aims to develop a reliable methodology that can meet the requirements of the requesting branches in a short span of time and at a low cost by studying the existing weapon effectiveness data production methodologies such as that of JMEM. As a result I have developed a method that calculates the vulnerable area and the probability of kill of the weapon system that one wants to calculate by applying statistical technique and simulation technique based on weapon effectiveness data of similar weapon systems in JMEM and live test data.

• Journal of Digital Convergence
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• v.19 no.10
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• pp.221-227
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• 2021

In this paper, we conducted word-to-word similarity analysis of standardized datasets collected through web crawling for 10,000 Vertical Noise Mouses using Word2Vec, and made 92 students of computer engineering use the products presented for 5 days, and conducted self-report questionnaire analysis. The questionnaire analysis was conducted by collecting the words in the form of a narrative form and presenting and selecting the top 50 words extracted from the word frequency analysis and the word similarity analysis. As a result of analyzing the similarity of e-commerce user's product review, pain (.985) and design (.963) were analyzed as the advantages of click keywords, and the disadvantages were vertical (.985) and adaptation (.948). In the descriptive frequency analysis, the most frequently selected items were Vertical (123) and Pain (118). Vertical (83) and Pain (75) were selected for the advantages of selecting the long/demerit similar words, and adaptation (89) and buttons (72) were selected for the disadvantages. Therefore, it is expected that decision makers and product planners of medium and small enterprises can be used as important data for decision making when the method applied in this study is reflected as a new product development process and a review strategy of existing products.

• Journal of the Korea Society for Simulation
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• v.30 no.3
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• pp.11-17
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• 2021

The 30mm anti-aircraft gun has been developed with various types of weapon systems such as protective, protective complex, and wheel-type anti-aircraft artillery. The role of this anti-aircraft gun is an important anti-aircraft weapon in charge of air defense. Anti-aircraft weapons are tasked with defending the airspace from aircraft attacks. In particular, anti-aircraft weapons are organized in combination with mechanized units. And anti-aircraft weapons are prone to attack by enemies because they operate on the front lines of the battlefield. The enemy is expected to attack our troops by covering up or concealing as much as possible in order to increase their viability. Therefore, this study analyzed whether our 30mm anti-aircraft bullets could subdue the enemy in cover. This study analyzed the performance of 30mm anti-aircraft bullets using the M&S technique. For this study, live shooting and simulation method by M&S were used for the experiment. In this study, steel plate and plywood were used for the live shooting experiment. In addition, in the simulation process through M&S, this study used the PRODAS model, AUTODYN model, and Split-x model to analyze the trajectory, penetration, and fragmentation capability of 30mm anti-aircraft bullets. According to the experimental results, it has been proven that 30mm anti-aircraft bullets can destroy enemy armored vehicles. 30mm anti-aircraft bullets succeeded in quickly subduing enemies concealed in general buildings or forests. In this way, it was possible to minimize damage to allies in advance.

• Journal of Digital Convergence
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• v.19 no.12
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• pp.243-253
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• 2021

In this study, AHP analysis was conducted on potential residents who are willing or likely to live in a smart city. The purpose is to identify priorities for strategic objectives. In order to establish a hierarchical structure for the vision, core values, and strategic goals of the smart city business, we researched domestic and overseas smart city-related academic papers and research reports, business plans, and institutional websites. After reviewing professors, researchers, experts, and focus groups, 4 2nd tier and 12 3rd tier properties were finally selected and the hierarchical structure was confirmed. As a result of AHP analysis, it was found that residents place the highest importance on quality of life in smart city projects. As a result of the analysis of the lower-level factors, it was found that safety was the most important. The priorities were analyzed in the order of living convenience, eco-friendliness, and social inequality resolution. It is expected that the results of this analysis will be able to suggest strategies to be established when promoting smart city projects in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.456-463
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• 2019

Micro climatic conditions within the livestock facility are affected by various factors such as ventilation, cooling, heating, insulation and latent and sensible heat generation from animals. In this study, numerical BES method was used to simulate energy flow inside the poultry house. Based on the BES method and THI concept, degree of thermal stress of poultry was evaluated according to the locations in South Korea. Comparison of THI values within the poultry house was also carried out according to the stocking densities to reflect recent animal-welfare issue. Significant decrease in thermal stress of poultry was observed when the stocking density of $30kg/m^2$ was applied in the change of the seasons(p<0.05) however, there was no statistically significant difference in summer season(p>0.05). It meant that installation of proper cooling system is urgently needed. For Iksan city of Jeollabuk-do province, total 252 hours of profit for thermal stress was found according to decrease in the stocking density.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.7-13
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• 2019

This study aims to develop a FE Model to simulate dissimilar friction stir welding and to address its potential for fundamental analysis and practical applications. The FE model is based on Coupled Eulerian-Lagrangian approach. Multiphysics systems are calculated using explicit time integration algorithm, and heat generations by friction and inelastic heat conversion as well as heat transfer through the bottom surface are included. Using the developed model, friction stir welding between an Al6061T6 plate and an AZ61 plate were simulated. Three simulations are carried out varying the welding parameters. The model is capable of predicting the temperature and plastic strain fields and the distribution of void. The simulation results showed that temperature was generally greater in Mg plates and that, as a rotation speed increase, not the maximum temperature of Mg plate increased, but did the temperature of Al plate. In addition, the model could predict flash defects, however, the prediction of void near the welding tool was not satisfactory. Since the model includes the complex physics closely occurring during FSW, the model possibly analyze a lot of phenomena hard to discovered by experiments. However, practical applications may be limited due to huge simulation time.

• Journal of Convergence for Information Technology
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• v.9 no.4
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• pp.1-7
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• 2019

The medical environment, combined with IT technology, is changing the paradigm for medical services from treatment to prevention. In particular, as ICT convergence digital healthcare technology is applied to hospital medical systems, infrastructure technologies such as big data, Internet of Things, and artificial intelligence are being used in conjunction with the cloud. In particular, as medical services are used with IT devices, the quality of medical services is increasingly improving to make them easier for users to access. Medical institutions seeking to incorporate IoT services into cloud health care environment services are trying to reduce hospital operating costs and improve service quality, but have not yet been fully supported. In this paper, a patient information collection model from hospital IoT system, which has established a cloud environment, is proposed. The proposed model prevents third parties from illegally eavesdropping and interfering with patients' biometric information through IoT devices attached to the patient's body at hospitals in cloud environments that have established hospital IoT systems. The proposed model allows clinicians to analyze patients' disease information so that they can collect and treat diseases associated with their eating habits through IoT devices. The analyzed disease information minimizes hospital work to facilitate the handling of prescriptions and care according to the patient's degree of illness.

• Journal of the Korean Geotechnical Society
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• v.34 no.11
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• pp.93-105
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• 2018

Precise investigation and interpretation of the ground subsidence risk factors needed to predict and evaluate the settlement problems of the surrounding ground due to the ground excavation. There are various geophysical exploration methods to investigate the ground subsidence risk factors. However, there are factors that influence the characteristics of the underground medium in these geophysical methods, and the actual soil contains complex factors affecting geophysical exploration. Therefore, it is necessary to analyze the effects on the geophysical methods based on the understanding of the geotechnical properties of soil. In this study, a test bed was constructed to consider various complicated factors in the complex ground and the ground behavior was analyzed by numerical analysis. In addition, we analyzed the limitations on investigating the ground subsidence risk factors through ground penetration radar (GPR) survey. As a result, ground subsidence of Open-cut Type Excavation is caused by various factors. Especially, in the case of soft ground condition, it was found that it was greatly influenced by the flow change of groundwater level. At the center frequency of GPR of 250 MHz, the attenuation of the electromagnetic wave is severely attenuated in the clay with high electrical conductivity, making it difficult to penetrate deeply into the ground (4 m below the surface). As the electromagnetic waves pass through the groundwater level below the groundwater, the attenuation of the electromagnetic waves becomes severe.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.1105-1123
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• 2018

The main risk factors of tunnel excavation through urban areas are ground settlement and surface sink which caused by ground conditions, excavation method, groundwater condition, excavation length, support method, etc. In the process of ground settlement assessment, the numerical analysis should be conducted considering the displacement and stress due to tunnel excavation. Therefore a technique that can simplify such process and easily evaluate the influence of tunnel excavation is needed. This study focused on the tunnelling-induced ground settlement which is main consideration of underground safety impact assessment. The parametric numerical analyses were performed considering such parameters as ground conditions, tunnel depth, and lateral distance from tunnel center line, etc. A simplified ground settlement evaluation chart was suggested by analyzing tendency of ground subsidence, lateral influence area and character by depth. The applicability of the suggested settlement evaluation chart was verified by comparative numerical analysis of settlement characteristics.