• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.99-112
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• 2014

This paper addresses an assessment model for selecting PL(Private Level) product companies. The proposed model extracts the weights of evaluation elements based on AHP(Analytic Hierarchy Process). These evaluation elements are from real-world instances in a domestic hyper market. Especially, the model points at food products which constitute a large portion of entire profits in the market. In this model, we first classify the 54 evaluation elements into 4 layers and secondly carry out a survey with relevant specialists based on them. We also estimate the weights of evaluation elements according to pairwise comparisons from the survey, and propose them as a quantitative alternative which can be applied in real-world problems. Finally, the pilot-study is conducted to compare the proposed model with the existing simple summation method. From this study, HACCP system assessment and Review(0.279281), Transportation(0.117706) and Fundamental law observance(0.066392) are presented as the key evaluation elements for selecting PL product companies. The proposed model facilitates the company selection among those candidate companies which is not easy to determine the superiority by reflecting the importance of evaluation elements.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.35-40
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• 2020

The ballast layers play a key role in distributing and supporting a trainload. On the other hand, it settles down by dynamic train loading due to large void ratios. Consequently, it requires continuous maintenance. In this paper, ballast layers mixed with three types of specially shaped artificial ballast (AB) (Rectangular, Tetrapod, Hexagonal) were modeled by using a two dimensional DEM (Discrete Element Method). Repeated loading tests were performed to evaluate the settlement behavior of the ballast layers. The smallest settlement was observed in the case of the ballast layer mixed with Tetrapod AB than in other cases, according to an analysis of the force transfer routes. In addition, contact force analysis showed that the Tetrapod AB, which has a concave shape, could easily make small and multi-channel force-transfer routes. This means that the stress in the ballast layer by the train loading transferred through the sleeper uniformly was distributed well by the AB. Therefore, the settlement of the ballast layer mixed with the concave-shaped Tetrapod AB could be reduced effectively under a repeated train loading. The effects of a decrease in settlement of the ballast layer highlight the possibility of a maintenance-free ballasted track.

• Resources Recycling
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• v.28 no.6
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• pp.26-35
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• 2019

This study aims to introduce and economical review on the possibilities of rare earth elements(REEs) recovery from coal ashes and the analysis of economical evaluation factors based on the data for securing domestic rare earth elements. The cut-off grade of REEs on recovering from coal ash was confirmed to be 1,000 ppm on total rare earth oxides(TREO) basis, and while the economic value of coal ash changed with contents and specific elements of rare earth elements. This shall be resulted in the price differences of rare earth elements required by the current industry, and it probably varies depending on the future demand of rare earth components. For developing of commercial recovery technology on REEs in coal ashes, many researches have been carried out by various analyzing methods, such as evaluation of holding value of REEs in ashes, assessment between supply and demand of industry, comparison of investment and its profitability for the REEs's production from coal ashes, and so on. Although these methods have been suggested, its recovery system with economical feasibility could not been confirmed up to present. In this reason, the process design of recovering REEs from coal ash shall be researched continuously to solve the problems of the global rare earth market. And also these researches shall be conducted actively in Korea for the purpose of securing the REEs resources and their recovering technologies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.9-17
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• 2017

Ensuring the safety of automobiles and trains during system operation is regarded as indispensable due to the progress in unmanned operation. The automotive functional safety standard, ISO 26262, has been proposed to ensure the safe design of vehicles. This standard describes in detail the required risk analysis and evaluation procedure and safety measures, while appropriately reflecting the system design information. Therefore, much research has been done on the risk analysis procedure, wherein the design information is mostly extracted from physical components of similar systems already in operation, the information traced back to obtain constituent functions, and then methods of identifying risk sources are studied. This method allows the sources of risk to be identified quickly and easily, however if the design requirements are changed or systems are newly developed, others may be introduced which are not accounted for, thereby yielding mismatched design information. To resolve this problem, we propose a top-down analysis in order to utilize the system design information appropriately. Specifically, a conceptual system is designed to obtain the functions, which are then analyzed. Then, a function-based fault tree analysis is conducted, followed by a risk source analysis. In this paper, a case study of automotive safety is presented, revealing that the proposed method can analyze the risk sources with reduced possibility of omission by systematically reflecting the system design information.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.315-321
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• 2017

This study investigated the problems of the tourism industry mostly focusing on the Chinese market and proposed strategic orientations by analyzing the inbound tourists from various countries. The study analyzed the relationships among satisfactions and expenditures of shopping, food, transportation, accommodation and intention to revisit for the inbound tourists in Korea and explored the differences in the relationships across the countries. The study results were analyzed via structural equation modeling (SEM) using AMOS with the data for inbound tourists in 2015. The results are summarized as follows. First, for Japanese tourists, the expenditures of accommodation, shopping and transportation were significantly related to their satisfaction, respectively, while for Chinese tourists, all the expenditures were significantly related to satisfaction in all areas. Expenditures of shopping and food for Southeast Asian tourists, of accommodation and shopping for North American tourists, and of shopping and transportation for European tourists had significant effects on satisfactions. Second, for Japanese tourists, shopping, food, and transportation satisfactions were significantly related to intention to revisit, while for North American and European tourists, all satisfactions but transportation satisfaction were significantly related to intention to revisit. The study results reveal the need to develop new products for various reasons of visit Korea for various countries and that our government will have to determine and solve the problems and meet the demands from the inbound tourists from various countries in terms of shopping and transportation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.147-156
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• 2016

The purpose of this study was to identify the factors associated with the improvement of metabolic syndrome, and provide basic data for the health management of clients. The subjects were 280 adults who were diagnosed with metabolic syndrome in 2013, and who were examined from January 2013 to December 2014. The data were analyzed by descriptive statistics, t-test, ${\chi}^2$-test, and logistic regression analysis with SPSS WIN 18. The change rate from 3 to 2 risk factors was 60.6% among those clients whose metabolic syndrome improved. The improvement group showed a decrease in their waist circumference, systolic blood pressure, triglycerides and increase in their HDL cholesterol in 2014 compared to 2013, as well as decreased drinking, increased exercise, proper calorie, protein and carbohydrate uptake, and increased consumption of a lipid lowering agent. Exercise, calorie uptake and maintenance of an oral hypoglycemic drug influenced the improvement of the metabolic syndrome. In conclusion, it is necessary to have an intervention program including exercise enhancement and diet modification and to reinforce the health education for continuing health management.

• Journal of Korea Spatial Information System Society
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• v.1 no.2 s.2
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• pp.81-98
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• 1999

The purpose of this study is to provide a common model and implementation strategies for reusing GIS components in local governments. The common model includes several solutions to remove stumbling blocks step by step in reusing or exchanging GIS application systems between local governments. Elements of the model are component architecture, common business process model, common function model, and data model. The elements are the minimum standards for reusability. In order to realize the desirable common model at present, however, the following problems remain : usable components are insufficient in spatial domains and existing GIS application systems require reinvestment to accommodate the new component technology. Three questions are raised to maximize reusability from a monolithic structure toward layered and the componentized GIS application systems : (1) How can the application systems be reused within a local government?, (2) Can the systems be exchanged when they are in the same computing platform?, and (3) When the systems are componentized by standardized interfaces, are the components replaceable between the systems in local governments? Some strategies are presented to accomplish the objectives implicated in the questions. For the actual implementation, several issues such as evaluation procedures for component products, ownership and commercialization issues, will be brought up in the future. Central and local governments, and commercial party need to co-operate each other to maximize the reusability. Reducing overlapping investments in local governments and obtaining competitive component technology in the commercial party should be recognized as critical tasks for the more efficient and economical GIS implementation.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.1
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• pp.122-131
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• 1992

An expert system is developed which can design the power transmission involute cylindrical gears on the basis of strength and durability. Bending strength, surface durability, scoring, and wear probability are considered as the basis. The basic components of the expert system are knowledge base, inference engine, and working memory. The knowledges in knowledge base are classified hierarchically into the knowledges used in selection of gear type, selection of materials, and determination of K factor and are represented by rules. In the inference engine two inference methods are implemented with the depth first search method. For-ward chaining method is introduced in the selection of gear type and materials and in the determination of K factor. Backward chaining method is introduced in the detailed design of module and face width in accordance with the validation of strength. And inference efficiency is achieved by constructing the part needing a lot of numerical calculations in strength estimation separately from inference mechanism. The working memory is established to save the results during inference temporarily. In addition, design database of past design results is built for consultation during design and knowledge acquisition facility, explanation facility, and user interface are included for the usefulness of user. This expert system is written with the PROLOG programming language and the FORTRAN language in numerical calculation part which interfaced with PROLOG and can also be executed on IBM-PC compatible computer operated by MS-DOS alone.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3740-3747
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• 2009

To protect the citizens' health of Gyeongju and to secure basic data for the assessment of health and environmental risk, distribution characteristics of meteorological elements were investigated and numerical simulation of wind field using RAMS model was carried out. In addition, measurement and analysis of air pollutants, forecasting the behavior air pollutants using ISC-AEROMOD view, and health and environmental risk-influenced zones were defined through managing air polluting materials to prevent health damage and property damage. According to the survey results of air pollution in Gyeongju and surroundings, average annual concentration of air pollutants in Gyeongju was slightly lower than that in Pohang and Ulsan areas, but concentration of particulate matters and nitrogen dioxide at Gyeongju Station Square and Yonggang Crossing were sometimes higher than that in Pohang and Ulsan areas. Results of the modeling of moving and diffusion of air pollutants that affect citizens' health showed that parts of the 1st through 4th industrial complexes together with POSCO were included in particulate matters and sulfur dioxide influenced areas in Pohang Steel Complex area, and that Haedo-dong, Sangdae-dong, Jecheol-dong and Jangheung-dong in Pohangnam-gu represented locally worsened air quality due to a quantity of air pollutant emission from dense steel industries and large scale industrial facilities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.542-547
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• 2013

In this study, mechanical property on the composite material of aluminum foam core is investigated by simulation analysis. Impact energies such as 50J, 70J, and 100J are applied to the specimen model. The maximum load occurs at 3.4ms for 50J, 3.2ms for 70J, and 3.2ms for 100J respectively. The striker penetrates the upper face sheet, causing the core to be damaged at 50J test but the lower face sheet remains intact with no damage. It results in occurring with the energy of 52 J. At 70J test, it penetrates the upper face sheet and penetrated the core. And the striker causes the lower face sheet with damage. And it results in occurring with the energy of 65 J. Finally at 100J test, the striker penetrated both the upper face sheet and core and even the lower face sheet. The load becomes maximum at the time when striker penetrates through the upper plate and it rapidly reduced. And then the load increases rapidly when reaching the lower face sheet. And it decreases again. It results in occurring with the energy of 95 J.