• Industrial Engineering and Management Systems
• /
• v.8 no.4
• /
• pp.221-227
• /
• 2009

There are customer services jointly provided by two facilities so that each customer will complete the course made up of both facilities' sub-services. The two facilities are assumed invested respectively by an infrastructure owner and one subordinate facility owner, whose partnership is built on their capital investments. This paper presents a mathematical model of Stackelberg competition between the two facility owners to derive their optimal Nash equilibrium. In this study, each facility owner's profit is consisted of fixed revenue fractions of sold services, operating costs (including depreciation cost) and maintenance costs of her facility. The maintenance costs of one facility are incurred both by failures and deterioration due to usage. Moreover, for both facilities, failures are rectified immediately by minimal repairs and preventive maintenance is carried out at a fixed time epoch. Additional assumptions are also employed to develop the model such as customer arrivals are manipulated to follow a Poisson process, and each facility's lifetime is independently Weibull-distributed. The Stackelberg game proceeds as follows. At the first stage of decision making process, the infrastructure owner (acting as a leader) decides the allocation of revenue shares based on her self-interest. After observing the allocation of revenue shares, the subordinate facility owner determines her own optimal price of services. This paper investigates actions and reactions of the two partners in the system. Then analytical conditions are proposed to achieve a unique optimal Nash equilibrium. Finally, some suggestions for further research are discussed.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.9 no.4
• /
• pp.173-178
• /
• 2004

Chronic Cochlodinium blooms in the southern waters of Korea have brought about considerable economic losses for about a decade, This paper aims to reframe current perspectives on the outbreak mechanism and the remediation schemes through a thought experiment in a context of mass balance and mathematical ecology. Far different explanations emerge from a careful examination of the scientifically unnoticed clues and a through discussion on the phytoplankton conservation equation. Logic of the eutrophication-induced red tide subjects to criticism. It is strongly recommended that the current remediation scheme to exterminate the target species should be rerouted to an environmentally sound competition enhancement tactics. Finally a novel convergence-float-aggregation hypothesis is proposed as an outbreak mechanism.

• Journal of the Korea Safety Management & Science
• /
• v.15 no.2
• /
• pp.255-262
• /
• 2013

Due to the competition between the various professional events, it is imperative for the team's management to improve efficiency by removing the inefficiencies of the professional team in order to gain a competitive edge. This study use different Data Envelopment Analysis (DEA) models to measure the efficiency of professional sport organizations. In this mathematical-analytical study, this study first reviews the related literature to analyze the input/output variables. In the end, the variables were detected and the data for this study were gathered from the Korean Basketball League (KBL). While previous studies examine relative efficiency of Korean Professional baseball teams by using CCR model, this study fully utilize the DEA method to investigate Korean professional sports organizations' operating problem. Thus, this study propose full results of DEA analysis such as efficiency score (overall, technical, and scale efficiency), slacks in inputs and outputs of inefficient organizations, Malmquist index) As a result, this study provides not only the exact productivity information of a team and a way of improving a firm's productivity with a decision maker.

• Korea Journal of Hospital Management
• /
• no.spc
• /
• pp.1-13
• /
• 2016

In a situation where competition becomes intense, health care organizations constantly strive to provide more services with given personnel and time. While not only the 'quantity' of the services but also the 'quality' becomes increasingly important, various problems that can occur during the 'process' of service provision can be effectively managed by applying the methods of management science. In this study, we introduce the cases where the methods of management science can be applied for the management of health care organizations in Korea and abroad. There are many cases where various scenarios for improving the patients' accessibility to the services and for maximizing the efficient use of limited resources are established, and simulation or basic statistical analysis methods are used to solve the problems more systematically or to develop improvement plans. In this study, several exemplary cases, such as no-show of patients, crowding in the emergency room, prediction of the number of available beds in the intensive care units, nurse scheduling, delay of arrival of patients, and ordering of the proper amount of therapeutic materials, are introduced and discussed. From the perspective of administrators or clinicians, however, it may not be easy to master the methodology that requires considerable mathematical background or apply the theories to practice directly. Therefore, it is suggested that more practical and relatively simple analytical methods should be applied. Also, having a more positive attitude toward improving the current performance (e.g., a belief that 'we can always be better than now'), and paying attention to improving the job satisfaction by addressing problems, with experimental spirit and data-driven decision management.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.6 no.6
• /
• pp.376-385
• /
• 2001

Considerable attention has been focused in recent years upon the field of biosorption for the removal of metal ions from aqeous effluents. Compared to other technologies, the advan-tages of biosortption are the high purity of the treated waste water and the cheap raw material. Really, the first major challenge for the biosorption field is to select the most promising types of biomass. Abundant biomass types either generated as a waste by-product of large-scale industrial fermentations particularly fungi or certain metal-binding seaweeds have gained importance in re-cent years due to their natural occurrence, low cost and, of course good performance in metal biosorption. Industrial solutions commonly contain multimetal systems or several organic and in organic substances that form complexes with metals at relatively high stability forming a very complex environment. When several components are present, interference and competition phe-nomena for sorption sites occur and lead to a more complex mathematical formulation of the process. The most optimal configuration for continuous flow-biosorption seems to the packed-bed column which gets gradually from the feed to the solution exit end. Owing to the com-petitive ion exchange taking place in the column, one or more of the metals present even at trace levels may overshot the acceptable limit in the column effluent before the breakthrough point of the trargeted metal. Occurrence of 'overshoot's and impact on havey metal removal has not been analyzed enough. New trends in biosorption are discussed in this review.

• The KIPS Transactions:PartD
• /
• v.12D no.6 s.102
• /
• pp.869-874
• /
• 2005

In the recent years there has been an increase of service competition in the activity of product selling, especially in the extension of warranty coverage and qualify. The variables in connection with the service competition are not crisp, and required the expertise of the production line. It thus becomes all the more necessary to use subtler tools as decision supports. These problems are typical not only of product companies but also of financial organizations, credit institutions, insurance, which need predictions of credibility for firms or persons in which they have any kind of interest. A suitable approach for minimizing the risk is to use a knowledge-based system. Most often expert systems are not standalone programs, but are embedded into a larger application. The aim of this paper is to discuss an approach for developing an embedded fuzzy expert system with respect to the product selling policy, especially to present the decision system of automobile selling activity around the extension of warranty coverage and quality. We use the MATLAB tools which integrates computation, visualization, and programming in an easy-to-use environment where problems and solutions are expressed in familiar mathematical notation. Also, we present the API functions embedding into the existing application.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.2
• /
• pp.483-496
• /
• 2018

NCS (National Competency Standards) has emerged as an issue of great importance amongst Korean universities and corporations. Although previously used mostly for vocational education purposes at colleges, NCS is currently receiving an increasing amount of attention from 4-year universities as well. In the ever-evolving information economy, the basic workplace skills defined by NCS, which include soft skills such as communication skills, problem-solving skills, and interpersonal skills, have now become more important than specific technical skills. This study analyzes the correlation between the basic workplace skills of NCS with participation in Formula SAE activities, a common component of Capstone design courses across North America and Europe. Data are derived from site visits to Formula SAE competitions, competition-related documents drafted by student participants, and questionnaires administered to student participants at the Formula SAE Lincoln completion and at the Korea KSAE competition. From the study findings, we claim that the basic workplace skills of NCS are closely correlated to participation in Formula SAE activities. Through a survey designed to measure the degree to which Formula SAE activities can enhance an individual's NCS Basic Workplace Skills, we find that these activities overall improved NCS basic workplace skills averaging 4.0 points above in the Likert 5-point scale. For reference the mathematical skills, communication skills, and problem-solving skills displayed statistically significantly correlation with NCS but the remaining 7 skills did not show a statistically strong correlation with NCS comparatively.

• Journal of Korean Society for Quality Management
• /
• v.45 no.4
• /
• pp.957-968
• /
• 2017

Purpose: There are lots of efforts to increase the revenue of on-line travel agency due to the extreme competition in the hospitality industry. One of the way to improve the revenue is applying new concepted service for their business. In this study, it is introduced an innovative system design of hotel reservation for the on-line travel agency using the concept of an opaque product. Methods: By adopting the opaque product at the hotel reservation system, the reservation requests can increase because the customer tends to feel that they purchase the hotel service with relatively cheap price. The overall process for an innovative hotel reservation system is presented and the core algorithm to implement this system is also suggested through a mathematical model based optimization method. Results: To validate and to examine the proposed process and core algorithm, a numerical example is provided with the modified data of the hotels in Seoul metropolitan city. The discount prices and the overall revenue of hotels are generated according to hotel grade. Conclusion: It is confirmed that the revenue of the hotel tends to increase according to its grade. This is because that the customer want to use the new service which applying the concept of opaque product when the higher discount ratio are decided for lower grade hotels.

• Korean System Dynamics Review
• /
• v.14 no.3
• /
• pp.25-49
• /
• 2013

As global competition for green car, that is environmentally friendly car, is getting tougher, the governments and the related industries are putting their core efforts in its diffusion. However, the green car sales are disappointing so far. To overcome the gridlock, it is necessary to develop concrete analytical framework to understand the diffusion process. Based on causal loop analysis from the previous work, we have identified main variables and relationships of them in the diffusion process and developed a stock-flow diagram and mathematical formula for the main components. The model would be applied for further quantitative simulation on the diffusion process of green car and other innovative goods as well. Also, we have suggested constructive insights for the policy makers and for the related industries. First, it is important to increase consumers' willingness to consider through marketing and word of mouth to accelerate the diffusion process. Second, in the perspective of the industry, the market share of green car should be increased at the earliest possible stage and this could be done by enhancing each components of green car attractiveness(e.g. price, driving range, social infra). Third, companies should develop a balanced investment between consumer and technology sector through a flexible financial policy. Fourth, the government continuously has the role of investing in the related R&D and social infra building. We expect the green car diffusion model and related formula from the research can provide meaningful tools to analyze the diffusion process of other new and innovative goods based on its deep researched literature review.

• Journal for History of Mathematics
• /
• v.21 no.4
• /
• pp.153-168
• /
• 2008

This study investigates how high achievers solve a given mathematical problem. The problem, which comes from 'SanHakIbMun', a Korean mathematics book from eighteenth century, is not used in regular courses of study. It requires students to determine the area of a gnomon given four dimensions(4,14,4,22). The subjects are 84 sixth grade elementary school students who, at the recommendation of his/her school principal, participated in the mathematics competition held by J university. The methods used by these students can be classified into two approaches: numerical and decomposing-reconstructing, which are subdivided into three and six methods respectively. Of special note are a method which assumes algebraic feature, and some methods which appear in the history of eastern mathematics. Based on the result, we may observe a great variance in methods used, despite the fact that nearly half of the subject group used the numerical approach.