• Journal of Environmental Impact Assessment
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• v.25 no.5
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• pp.345-356
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• 2016

In this study, auto-calibration method for water quality model was compared and analyzed using QUAL2Kw, which can estimate the optimum parameters through the integration of genetic algorithm and QUAL2K. The QUAL2Kw was applied to the Sum River which is greatly affected by the pollution loads of Wonju city. Two auto-calibration methods were examined: single parameter application for the whole river reach and separate parameter application for each reach of multiple reaches. The analysis about CV(RMSE) and fitness of the GA show that the separate parameter auto-calibration method is better than the single parameter method in the degree of precision. Thus the separate parameter auto-calibration method is applied to the water quality modelling of this study. The calibrated QUAL2Kw was used for the three scenarios for the water quality management of the Sum River, and the water quality impact on the river was analyzed. In scenario 1, which improve the effluent water quality of Wonju WWTP, BOD and TP concentrations of the Sum River 4-1 station which is representative one of Mid-Watershed, are decreased 17.7% and 29.1%, respectively. And immediately after joining the Wonjucheon, BOD and TP concentrations are decreased 50.4% and 40.5%, respectively. In scenario 2, Wonju water supply intake is closed and multi-regional water supply, which come from other watershed except the Sum River, is provided. The Sum River water quality in scenario 2 is slightly improved as the flow of the river is increased. Immediately after joining the Wonjucheon, BOD and TP concentrations are decreased 0.18mg/L and 0.0063mg/L, respectively. In scenario 3, the water quality management alternatives of scenario 1 and 2 are planned simultaneously, the Sum River water quality is slightly more improved than scenario 1. Water quality prediction of the three scenarios indicates that effluent water quality improvement of Wonju WWTP is the most efficient alternative in water quality management of the Sum River. Particularly the Sum River water quality immediately after joining the Wonjucheon is greatly improved. When Wonju water supply intake is closed and multi-regional water supply is provided, the Sum River water quality is slightly improved.

• Journal of the Ergonomics Society of Korea
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• v.24 no.3
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• pp.35-41
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• 2005

The KOSHA codes H-31 and H-30 provide general guidelines to establish a prevention program for work-related musculoskeletal disorders(WMSD). Understanding of the components and practitioner needs for a WMSD prevention program is necessary for effective revision and implementation of the KOSHA codes. The present study established a comprehensive structure for a WMSD prevention program and surveyed practitioner needs for the KOSHA codes. The comprehensive prevention program structure, consisting of 7 parts(organization, education, risk management, medical management, program evaluation, and record keeping) and 90 items, was constructed by analyzing WMSD prevention guidelines published by various government agencies such as KOSHA, OSHA and NIOSH. Next, 20 practitioners, from four industry sectors(auto manufacturing, auto part manufacturing, shipbuilding, and machinery), working in a safety and health department or labor union, were interviewed to collect opinions for the KOSHA codes in terms of relevance, government support, and additional information needed. Guidelines of the KOSHA codes requiring modifications and government supports were identified, which can be used to revise the KOSHA codes and to establish a government policy to promote the implementation of the KOSHA codes. Lastly, the survey revealed that integrated, customized, quantitative, and case information for WMSD prevention is additionally needed, which can be used as design guidelines for a WMSD prevention program manual for practitioners.

• Journal of Distribution Science
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• v.15 no.8
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• pp.29-36
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• 2017

Purpose - This paper proposes some ideas with a view to reducing any possible accidents caused by unlicensed drivers and an illegal use of other's name, particularly by teenagers in consideration of easy and simple instruction on smartphone with very weak and mere consciousness on auto life. Research design, data, and methodology - This study analyzes some accident cases between cargo trucks and rental cars in South Korea, and unlicensed vehicle with unlicensed drivers who use rental cars collided with cargo trucks which were loaded a lot of goods to be delivered to buyer designated. In order to fulfill this research, a case study accompanied with literature survey was conducted. Ideal suggestion for the right growth on rental car industry will be realized by legislation of the law. Results - This paper classified bodily injury of the victim, property damage and damaged cargo arising out of the unlicensed who is driving on car sharing service in South Korea. Conclusions - For the purpose of reducing cargo accidents caused by unlicensed drivers and an illegal use of other's name particularly by teenagers, this paper proposes some ideas of Amendment of the law, Paradigm shift of car sharing company, Preparation by association side and Technical Complementary Measures in South Korea.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.72-79
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• 2005

This paper deals with the construct of e-SCM System for a supply chain of an auto-mobile company. Two first vendors and two second vendors of a bus company are included in the objects of developing e-SCM system. We analyzed the information flow and business process within vendor and between vendors by using data flow diagram, to describe process to-be model of the e-SCM system. And to analyze and design the process of the system, we used Unified Modeling Language.

• Asia pacific journal of information systems
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• v.26 no.4
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• pp.526-541
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• 2016

This research aims to examine the predictive power of multiple online stock message boards, namely, NAVER Finance and PAXNET, which are the most popular stock message boards in South Korea, in stock market activities. If predictive power exists, we then compare the predictive power of multiple online stock message boards. To accomplish the research purpose, we constructed a panel data set with close price, volatility, Spell out acronyms at first mention.PER, and number of posts in 40 companies in three months, and conducted a panel vector auto-regression analysis. The analysis results showed that the number of posts could predict stock market activities. In NAVER Finance, previous number of posts positively influenced volatility on the day. In PAXNET, previous number of posts positively influenced close price, volatility, and PER on the day. Second, we confirmed a difference in the prediction power for stock market activities between multiple online stock message boards. This research is limited by the fact that it only considered 40 companies and three stock market activities. Nevertheless, we found correlation between online stock message board and stock market activities and provided practical implications. We suggest that investors need to focus on specific online message boards to find interesting stock market activities.

• Journal of the Korea Safety Management & Science
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• v.12 no.3
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• pp.257-262
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• 2010

The study investigates the various Acceptance Control Charts (ACCs) based on the factors that include process independence, data weighting scheme, subgrouping, and use of control charts. USL - LSL > $6{\sigma}$ that used in the good condition processes in the ACCs are designed by considering user's perspective, producer's perspective and both perspectives. ACCs developed from the research is efficiently applied by using the simple control limit unified with APL (Acceptable Process Level), RLP (Rejectable Process Level), Type I Error $\alpha$, and Type II Error $\beta$. Sampling interval of subgroup examines i.i.d. (Identically and Independent Distributed) or auto-correlated processes. Three types of weight schemes according to the reliability of data include Shewhart, Moving Average(MA) and Exponentially Weighted Moving Average (EWMA) which are considered when designing ACCs. Two types of control charts by the purpose of improvement are also presented. Overall, $\alpha$, $\beta$ and APL for nonconforming proportion and RPL of claim proportion can be designed by practioners who emphasize productivity and claim defense cost.

• Journal of the Korea Safety Management & Science
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• v.14 no.1
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• pp.129-136
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• 2012

This study proposes a collaboration system framework on the web service in a supply chain to implement an efficient virtual supply chain and improve an ability to fulfill received orders over a supply chain. The system based on the framework proposed in this paper plays an important role for automatic order negotiation and placing/receiving an order noticed in web service by the main system. Furthermore, it can evaluate the fulfillment of received orders over a supply chain by using the transaction results from hierarchically related vendors and establish efficient manufacturing plans. In a word, this system is the automated system for creating manufacturing plans, placing and receiving orders. A little more important main function of this system is that it has a dynamic evaluation capability about fulfillment with received orders over a supply chain, and improves the evaluation method of fulfillment ability with received orders with related to direct dealing vendors, which is a main problem in existing system. As a result, this system is able to reduce the work load of the sales and purchasing materials, production control division, to manage accurate inventory promptly, to maintain the optimal inventory level by analyzing the information of fulfillment ability with received orders, and to enhance the level of service for customers.

• Journal of Korean Society for Quality Management
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• v.49 no.4
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• pp.539-550
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• 2021

Purpose: The purpose of this study is to propose a multivariate CUSUM control chart that can detect the out-of-control state fast while monitoring the cross- and auto- correlated multivariate time series data. Methods: We first build models to estimate the observation data and calculate the corresponding residuals. After then, a multivariate CUSUM chart is applied to monitor the residuals instead of the original raw observation data. Vector Autoregression and Artificial Neural Net are selected for the modelling, and Separated-MCUSUM chart is selected for the monitoring. The suggested methods are tested under a number of experimental settings and the performances are compared with those of other existing methods. Results: We find that Artificial Neural Net is more appropriate than Vector Autoregression for the modelling and show the combination of Separated-MCUSUM with Artificial Neural Net outperforms the other alternatives considered in this paper. Conclusion: The suggested chart has many advantages. It can monitor the complicated multivariate data with cross- and auto- correlation, and detects the out-of-control state fast. Unlike other CUSUM charts finding their control limits by trial and error simulation, the suggested chart saves lots of time and effort by approximating its control limit mathematically. We expect that the suggested chart performs not only effectively but also efficiently for monitoring the process with complicated correlations and frequently-changed parameters.

• Journal of Digital Convergence
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• v.12 no.2
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• pp.211-221
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• 2014

The study aims to estimate the determinants of policyholder's trust for the Chinese insurance industry by structural equation model. In particular, differences in determinants of trust among Chinese life insurance and auto insurance were derived from the latent mean and multi group analysis. The result shows the most effective determinants of trust were honesty, followed by credibility which shows the compensation ability of insurance company. However, benevolence is not influence statistically on the determinants of trust of both life insurance and auto insurance. Moreover, the policyholder's trust for the insurance industry was later extended to relationship commitment such as renewal and recommendation intentions. Especially, the linkage between the level of trust and relationship commitment was the strongest in life insurance than auto insurance. Even though the result is differ based on types of insurance, in order for the insurance industry to grow stably it is importance to get trust from policyholder.

• KNOM Review
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• v.23 no.2
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• pp.1-10
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• 2020

Network Function Virtualization (NFV) is a key technology of 5G networks that has the advantage of enabling building and operating networks flexibly. However, NFV can complicate network management because it creates numerous virtual resources that should be managed. In NFV environments, service function chaining (SFC) composed of virtual network functions (VNFs) is widely used to apply a series of network functions to traffic. Therefore, it is required to dynamically allocate the right amount of computing resources or instances to SFC for meeting service requirements. In this paper, we propose Deep Q-Networks (DQN)-based auto-scaling to operate the appropriate number of VNF instances in SFC. The proposed approach not only resizes the number of VNF instances in SFC composed of multi-tier architecture but also selects a tier to be scaled in response to dynamic traffic forwarding through SFC.