• The Journal of Korea Robotics Society
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• v.10 no.4
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• pp.200-212
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• 2015

In classical dynamics, the coefficient of restitution is one of variables to estimate the amount of impulse. In general, we have considered the coefficient of restitution as a constant value. However, coefficient of restitution (COR) is the function of contact material and colliding velocity. Furthermore, COR is also a function of contact area. Thus, without considering the variable characteristic of COR, the actual motion of an object just after impact is not the same as we expect. A general COR model is proposed in this work and its effectiveness is verified through a cart impact experiment and its result is applied to simulation of a ball impact problem. A three-degree-of-freedom manipulator is employed as a test-bed.

• Journal of Mechanical Science and Technology
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• v.20 no.8
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• pp.1101-1117
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• 2006

In the present article, recent progress of spray-wall interaction research has been reviewed. Studies on the spray-wall interaction phenomena can be categorized mainly into three groups: experiments on single drop impact and spray (multiple-drop) impingement, and development of comprehensive models. The criteria of wall-impingement regimes (i.e., stick, rebound, spread, splash, boiling induced breakup, breakup, and rebound with breakup) and the post-impingement characteristics (mostly for splash and rebound) are the main subjects of the single-drop impingement studies. Experimental studies on spray-wall impingement phenomena cover examination of the outline shape and internal structure of a spray after the wall impact. Various prediction models for the spray-wall impingement phenomena have been developed based on the experiments on the single drop impact and the spray impingement. In the present article, details on the wall-impingement criteria and post-impingement characteristics of single drops, external and internal structures of the spray after the wall impact, and their prediction models are reviewed.

• Journal of Distribution Science
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• v.13 no.12
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• pp.85-94
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• 2015

Purpose - The purpose of this paper is to provide a political registration point for analyzing the economic impacts on the national economy from the REITs distribution industry in our country. The REITs distribution industry was introduced in 2001 to accelerate the corporate restructuring process and advance the real estate market. During its establishment, the REITs distribution industry faced difficulties; however, the industry grew rapidly through interest from institutional investors, thus mitigating the establishment problems by 2006. In Korea, more than 108 REITs were operating as of the end of June 2015. REITs contribute significantly to the national economy. The economic impacts on the national economy of the REITs distribution industry was analyzed using input-output (I-O) analysis with respect to production, imports, value-added, and employment. Research design, data, and methodology - The research used an I-O analysis of the activities of the REITs distribution industry in the national economy. The I-O analysis methodology analyzes the economic effects that influence other industries with respect to one unit of external investment. The data for this analysis were the I-O table of 2013 as published by the Bank of Korea in 2014. Results - The findings of this study are as follows. First, if an external input to the REITs distribution industry is 1 won, the overall impact of the product is 1.3869 won, the import induction is 0.0002 won, and the value-added induction is 0.7656 won. A new investment of 659.9 billion won into the REITs industry was estimated to produce a gross effect of 915.2 billion won. Second, if an external input to the REITs distribution industry is 1 billion won, the employment-inducing effects are estimated at 19.6394 individuals. The employment-inducing coefficient of 19.6394 for the REITs distribution industry indicates that the industry created significant employment-more than other industries-because the coefficient was 2.2 times the 2013 industry average employment-inducing coefficient of 8.8. Third, the investment effects of the REITs distribution industry on production induction, value-added induction, and employment induction are assumed to be large in business support services, financing, communications and broadcasting, and professional, scientific, and technical services. Conclusions - The REITs distribution industry was analyzed as having a strong employment inducing, high value added effect. The REITs distribution industry is an excellent alternative for the government authority to create multilateral jobs. Because the REITs distribution industry has a significant positive impact on the national economy, it should be developed. However, the I-O methodology has restrictions with respect to the fixation and timing of the input coefficient. Follow-up research is expected to supplement the analysis method at a specific point in time.

• Journal of Environmental Impact Assessment
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• v.21 no.1
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• pp.1-13
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• 2012

We diagnosed on status and problems of environmental assessment regarding development of offshore wind power, and also on reasonable core assessment items. Most of the coastal wind power are located on the western coastline of Korea and Jeju Island. In the selections of the site for the offshore wind farms, a previous investigations should be conducted with regard to distances from the land, stabilities from external forces (tide, wave, etc.) and topographical changes, and characteristics of the surroundings (distributions of protected area, fishing ground, artificial seagrasses, and shipping traffic). It is needed to assess dispersion of suspended solids, changes of the sea bottom, and impacts on fisheries resources and fishing activities under construction of offshore wind power. Furthermore, the responses of marine organisms to noise and vibration, impacts by electromagnetic fields, impacts on sea birds, hindrances to sea lane routes, and damaged scenery and marine protection areas are thoroughly assessed during operation processes. The consultation criteria in case of development of offshore wind farm is adjusted by focusing marine environmental impact assessment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.5
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• pp.2131-2139
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• 2013

This study clearly identify the correlation between adolescents resiliency and suicidal ideation and more effective to strengthen the external protective factors for adolescents suicide prevention alternatives presented. Research subjects were 243 boy and girl first year students in a high school located in Kyunggi Province; Questionnaires were distributed for one week from March 5, 2013. Frequency analysis, correlation analysis, multiple regression analysis, t-test, one-way ANOVA, etc. were executed. All empirical tests were verified with 5% of significance level. From the result of analysis, suicidal ideation has a negative correlation with the adolescent resilience, and especially, when interaction in family dimension and the care, expectation level of school and peer dimension become higher, suicidal ideation was reduced. The implications of this study suggest that the material prepared for suicide prevention policy based on the results of a study on the impact of adolescents resiliency to suicidal ideation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7204-7213
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• 2014

This study examined the impact on work life on health recognition and health behavior practices. The data was collected from 314 flight attendants from June to July 2014 in A airline. Questionnaires were used to measure the levels of health recognition, health behavior practice, Stress index, external image, and the impact on the work life. The data was analyzed using descriptive statistics, T-test, ANOVA, Pearson's correlation, structural equating model using the SPSS AMOS 18.0 program. The research showed that health care influences the external image and work life, and the health behavior practice influences the stress management. A survey of the various influencing factors of work life will be needed in terms of human resource management to provide quality service to customers, and health care programs for flight attendants in workplace will be needed.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.10 no.5
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• pp.219-231
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• 2015

Open innovation is known to have a significant impact on the performance of enterprise innovation. The role of open innovation is more critical due to small scale and limitation on the available resources for the venture company. This study focused on the relationship among Entrepreneurship(ENT), Innovation Capability(IC), and External Cooperation(EC), which affect Technological Innovation Performance(TIP) to maximize TIP. Empirical study was proceeded to analyze the relationships among ENT, IC, EC, and TIP for venture companies in Busan. ENT was verified to have a positive impact on IC, EC, and TIP. IC was done on EC and TIP. EC was done on TIP. Each of IC and EC showed positive mediating role in the relationship between ENT and TIP. Finally, IC and EC together performed positive mediating role in the relationship between ENT and TIC.

• Korean Management Science Review
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• v.33 no.2
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• pp.11-28
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• 2016

This study empirically investigated the relationships among external factors (i.e., the imitation, compulsory and normative pressures, and governmental regulation), proactive environmental strategy, the adoption of green-supply chain management (GSCM) techniques, green corporation with suppliers, environmental performance, and organizational performance. To empirically demonstrate the relationships, 78 sample firms' data were collected from Korean manufacturing firms that are listed on the Korean stock market. The results of this study showed that a proactive environmental strategy mainly and positively influences the adoption of GSCM, and the introduction of a proactive environmental strategy is significantly and positively affected by governmental regulation. It was also found that governmental regulation has an indirect impact on the adoption of GSCM through the introduction of a proactive environmental strategy. Thus, it is asserted that governmental regulation, in Korean manufacturing firms, is the unique external factor on the adoption of a proactive environmental strategy, which facilitates the use of GSCM techniques. According to the results, it was observed that GSCM positively influences the levels of green corporation, and both GSCM and green corporation have positive effects on the improvement of environmental performance. Hence, it is suggested that the implementation of GSCM inevitably brings high degrees of green collaboration with suppliers. Finally, it was found that environmental performance has a significant and positive impact on the organizational performance of a firm. This result implies that high degrees of environmental performance, which bring both the efficient usage of materials and energy and the elimination of wastes, can lead to the increase of organizational performance.

• Journal of the Korean GEO-environmental Society
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• v.11 no.6
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• pp.39-46
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• 2010

The past studies on reinforced earth retaining wall have been mostly focused on the internal and external failure of reinforced earth retaining wall, and the research for external impact was limited on earthquake. However, the potential external impact such as vehicle collision to reinforced earth retaining wall near the road are increasing with development of roads. Therefore, in this study, the reinforced earth retaining wall was modeled by using LS-DYNA, which is a general purpose finite element program recognized for its reliability. The behavior of reinforced earth retaining wall by vehicle speed was analyzed with Ford single unit truck offered by NCAC (National Crash Analysis Center), which is 8 tons weight. In addition, in order to obtain stability of reinforced earth retaining wall for vehicle collision, the gravity retaining wall was applied at the bottom of reinforced earth retaining wall. With varying the height of retaining wall (0.5m, 1.0m, 1.5m), the numerical study was performed to analyze the stability and behavior of reinforced earth retaining wall.

• Journal of Soil and Groundwater Environment
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• v.26 no.5
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• pp.60-76
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• 2021

The concept of resilience seems applicable for sustainable groundwater management. The resilience is broadly defined as the ability of a system to resist changes by external forces (EFs), and has been used for disaster management and climate change adaptation, including the groundwater resilience to climate change in countries where groundwater is a major water resource, whereas not yet in the geological society of South Korea. The resilience is qualitatively assessed using the absorptive, adaptive, and restorative capacity representing the internal robustness, self-organization, and external recovery resources, respectively, while quantitatively using the system impact (SI) and recovery effort (RE). When the groundwater is considered a complicated system where physicochemical, biological, and geological components interact, the groundwater resilience can be defined as the ability of groundwater to maintain the targeted quality and quantity at any EFs. For the quantitative assessment, however, the resilience should be specified to an EF and measurable parameters should be available for SI and RE. This study focused on groundwater resilience to two EFs in urban areas, i.e., pollution due to land use change and groundwater withdrawal for underground structures. The resilience to each EF was assessed using qualitative components, while measurements for SI and RE were discussed.