• Journal of Communications and Networks
• /
• v.15 no.2
• /
• pp.228-239
• /
• 2013

Peer-to-peer (P2P) systems have proved the most effective and popular file sharing applications in recent years. Previous studies mainly focused on equal service and differentiated service strategies when peers have no initial data before their downloads. For an upload-constrained P2P file sharing system, we model both the equal service process and the differentiated service process when the initial data distribution of peers satisfies some special conditions. Moreover, we show how to minimize the time required to distribute the file to any number of peers. The proposed fluid-based models can reveal the intrinsic relations among the initial data amount, the peer set size, and the minimum last finish time. The closed-form expressions derived from the extended models can closely approximate chunk-based models and systems, especially for relatively large files. As an application of the extended models, we show how to provide differentiated service efficiently to multiple peer sets. Since no limits are imposed on the upload bandwidth of peers or the size of each peer set, we believe that our analytic process and the results achieved can provide not only fundamental insights into bandwidth allocation and data scheduling but also a helpful reference for both improving system performance and building an effective incentive mechanism for P2P file sharing systems.

• Journal of the Korean Society of Safety
• /
• v.29 no.3
• /
• pp.121-128
• /
• 2014

Risk assessment system which is the point of occupational safety and health management system is recognized to be effective to prevent industrial accident and occupational disease internationally. Ministry of Employment and Labor developed guidance on risk assessment at workplace recently. This guidance presents standard model on risk assessment at workplace. However, enterprises may be confronted with many questions in the process of introducing and operating risk assessment. For risk assessment to be implemented properly and effectively at workplace, there are various questions that need to be considered in advance, including giving shape to standard on risk evaluation and clarifying the implementation system at workplace in advance. Also for risk assessment to be revitalized at workplace, several policy matters need to be settled. First, an administrative agency should present the implementation method of risk assessment more concretely. Secondly, it is necessary for an administrative agency to develop and spread various detailed manual, models and good practices related to risk assessment. Thirdly, a government agency need to apply an incentive & disadvantage policy actively to risk assessment.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.4
• /
• pp.810-819
• /
• 2016

Uncoordinated charging of large-scale electric vehicles (EVs) will have a negative impact on the secure and economic operation of the power system, especially at the distribution level. Given that the charging load of EVs can be controlled to some extent, research on the optimal charging control of EVs has been extensively carried out. In this paper, two possible smart charging scenarios in China are studied: centralized optimal charging operated by an aggregator and decentralized optimal charging managed by individual users. Under the assumption that the aggregators and individual users only concern the economic benefits, new load peaks will arise under time of use (TOU) pricing which is extensively employed in China. To solve this problem, a simple incentive mechanism is proposed for centralized optimal charging while a rolling-update pricing scheme is devised for decentralized optimal charging. The original optimal charging models are modified to account for the developed schemes. Simulated tests corroborate the efficacy of optimal scheduling for charging EVs in various scenarios.

• International Area Studies Review
• /
• v.13 no.3
• /
• pp.439-458
• /
• 2009

In this paper, Two countries have invested directly using the two models Multinational Enterprises, foreign companies doing R&D subsidy policy analysis in their activities to attract. Multinational Enterprises to get the spillover effect from competitors, the introduction of subsidiary R&D resources with an incentive to R&D activities. The government has established a subsidiary to bring the country to foreign Multinational Enterprises for the purpose of improving the technological capabilities of Multinational Enterprises with their parent company R&D to increase the resources by foreign companies in their R&D investment to subsidize R&D activities that have an incentive to attract. In addition, foreign companies and government cooperative R&D by two things also increase the rate of funding for activities to bring the two subsidiaries of multinational R&D has increased the amount of additional resources, the economic interests of both countries get more will increase.

• Korea Journal of Hospital Management
• /
• v.13 no.3
• /
• pp.69-93
• /
• 2008

Rising healthcare cost is a global phenomenon that justifies governments' introduction of 'incentive regulation' plan for the improvement of hospital efficiency. A number of previous studies tried to evaluate the efficiency of healthcare organization by using Data Envelopment Analysis(DEA), a common efficiency benchmarking method. However, there is a concern that this kind of efficiency evaluation could induce "quantity-quality trade-off". Moreover, as quality aspect is especially important in terms of 'effectiveness' of health care, it should be considered in efficiency evaluation of healthcare organization. A number of different models were tried so far to incorporate quality aspect into DEA, however, none is universally recognized as a standard. Thus, in this study, previous quality-incorporating DEA models were categorized into 6 types according to the way of incorporating quality aspect, and strengths and limitations of each type were reviewed with a set of artificial data as an example. Based on this review, a new quality-incorporating efficiency evaluation model, named Quality-adjusted output DEA(QAO-DEA), was suggested. As an exploratory empirical analysis, technical efficiency of human resource were measured with different quality-incorporating DEA models, using 2004 data from National University Hospitals. In conclusion, Quality-adjusted output DEA(QAO-DEA) model seems to be one of the most desirable alternatives to incorporate quality aspect in efficiency evaluation of hospital, and deserves the consideration as a policy tool to induce simultaneous improvement of both efficiency and quality.

• Journal of Korea Technology Innovation Society
• /
• v.3 no.3
• /
• pp.36-52
• /
• 2000

This study takes an issue of efficiency analysis in the presence of network effect utilizing the DEA (Data Envelopment Analysis) framework. Network effect has important policy implication for the regulation of local monopolies which undertake their business through physical network, such as electricity, natural gas, local telephony, etc. If the difference in spatial condition between companies is not controlled properly, the performance comparison and associated incentive regulation bear significant bias. In this study, we propose a methodology to measure the true managerial or technical efficiency apart from efficiency difference accruing from the difference in spatial condition. A series of modified DEA efficiency models are combined to investigate the extent of exogenous and endogenous efficiency component in the Korean natural gas distribution companies. Empirical results show that the network effect plays significant role in determining superficial performance difference.

• Management Science and Financial Engineering
• /
• v.11 no.3
• /
• pp.61-78
• /
• 2005

The aim of this paper is to identify the barriers to the B2B e-commerce development in China's pharmaceutical industry and to devise an effective strategy for its future development. Built on a detailed investigation of the market structure and recent development of electronic commerce in China's pharmaceutical industry, this paper proposes that the key issue in the development of effective B2B e-commerce business models is the successful transformation of the inter- organizational information systems into electronic marketplaces. In order to ensure the success of such electronic marketplaces, a government driven approach will be needed. In the process, designing an incentive compatible mechanism of coordinating the interest of all the market players will be the prerequisite.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2004.10a
• /
• pp.539-553
• /
• 2004

This paper models and solves contracting schemes for both when quality is perfectly observable and when quality is not perfectly observable in supply chain. When quality is perfectly observable, the first-best optimal solution which is that the marginal utility of procurer obtained from the quantity and quality supplied by suppliers (the price) is equal to the marginal cost to produce the quantity and quality is obtained. However, when quality is not perfectly observable to procurers the optimal solution cannot be the first-best but the second-best where the price is greater than the marginal cost to produce the quantity and quality and social welfare is less than that of the first-best solution.

• Korean System Dynamics Review
• /
• v.17 no.1
• /
• pp.5-24
• /
• 2016

This study structurally analyzes major inefficiency of Korea's healthcare delivery system by utilizing the systems thinking. In particular, the phenomenon of patient's concentrated visits to large hospitals, waste of resource due to competitions between clinics and large hopitals, and the structure of oversupply were visualized using the causal loop diagram. The inefficient structure of healthcare delivery system can be understood more clearly by utilizing the major system archetypes of 'success to the successful', 'tragedy of commons', 'escalation' and 'limits to growth'. This study also finds solution from archetypal structure suggested by Wolstenholme. The inefficient status of healthcare delivery system might be explained by the 'out of control' archetype. In conclusion, the public resources such as the national health insurance need to be acknowledged as the entire achievement. All the participants should cooperate with each other in order to improve the inefficiency of the healthcare delivery system. In addition, the arrangement of incentive system for cooperation, acceleration of health information technology, and development of innovative business models make the sustainable healthcare delivery system.

• Journal of Distribution Science
• /
• v.17 no.7
• /
• pp.87-98
• /
• 2019

Purpose - The goal of this research is to examine the influence of Quick Response on the supply chain performance. Furthermore, this study investigates the potential of Quick Response to be a more advanced form of supply chain collaboration program with extensive information sharing activities. Research design, data, and methodology - The mathematical model is developed to represent the two stage supply chain system with a single manufacturer and one retailer. In the numerical study with the proposed mathematical models, three supply chain systems including the traditional system, Quick Response, and the fully shared information system are compared in terms of their profits. Results - The numerical analysis shows both manufacturer and retailer obtain greater profits under Quick Response than in the traditional system. While the fully shared information outperforms Quick Response as well as the traditional system, it results in lower manufacturer's profit compared with Quick Response. Conclusions - According to the numerical examples, Quick Response is the effective supply chain collaboration program that is beneficial to every supply chain member. The fully shared information system, as a more advanced form of collaboration than Quick Response can bring more benefits to the whole supply chain system, but it is necessary to prepare the proper incentive program that enables every member to share its benefits equally.