• Journal of the Korean Operations Research and Management Science Society
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• v.16 no.1
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• pp.76-88
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• 1991

Stochastic convexity (concavity) of a stochastic process is a very useful concept for various stochastic optimization problems. In this study we first establish stochastic convexity of a certain class of Markov additive processes through probabilistic construction based on the sample path approach. A Markov additive process is abtained by integrating a functional of the underlying Markov process with respect to time, and its stochastic convexity can be utilized to provide efficient methods for optimal design or optimal operation schedule wide range of stochastic systems. We also clarify the conditions for stochastic monotonicity of the Markov process. From the result it is shown that stachstic convexity can be used for the analysis of probabilitic models based on birth and death processes, which have very wide applications area. Finally we demonstrate the validity and usefulness of the theoretical results by developing efficient methods for the optimal replacement scheduling based on the stochastic convexity property.

• Journal of Digital Convergence
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• v.12 no.3
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• pp.399-414
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• 2014

The Princess Bari, an epic song passed down orally among the korean shamans, describes the process of its heroine's becoming a shaman. The life of a shaman coincides with the image of Mother Goddess that created human beings in that her role was to connect the life here and hereafter in Korea. Princess Bari, an abandoned daughter, experiences the world of death, sacrifices herself completely for her parents, devotes to her husband and gives birth to seven sons. She is a Mother Goddess who embraces fecundity and fertility, creation and destruction, and life and death. Furthermore, she is a "warm-hearted Mother Goddess" who takes the deceased to their last journey with maternal care. The number "seven", known to be a very significant number in human lives and the world after death, symbolizes how princess Bari had to be born as the seventh girl of her parents, not as the fifth or the sixth.

• The KIPS Transactions:PartC
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• v.9C no.3
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• pp.399-406
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• 2002

We consider design of multiservice network link, in which connections of constant- and adaptive-rate services arrive and leave dynamically. We propose performance analysis and design methods of these dynamic multiservice networks. A multiservice network link is modeled by a Markov chain, and data rates for adaptive-rate connections are derived using QBD (Quasi-Birth-Death) processes and matrix-geometric equations. We estimate average number of adaptive-rate connections, average data rate and average connection delay. The performance of constant-rate connections is determined from the blocking probability of the connections. Based on the performance of constant-and adaptive- rate connections, we propose a design methods of a network link to satisfy performance requirements of constant- and adaptive-rate connections (data rates, delay, blocking probability). Our methods can be used for the analysis and design of network switch supporting dynamic data and voice (video) traffic simultaneously.

• Journal of Korean Academy of Nursing
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• v.26 no.4
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• pp.759-767
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• 1996

This study was done to provide an understanding of nursing in relation to the existential philosophy of the West and Buddhistic philosophy, It examined how human beings and death are interpreted and understood in existential philosophy as well as in Buddhistic philosophy. Then the study suggested that nursing should focus on helping the sufferer to find meaning and a sense of responsibility in his or her existence. When people have the opportunity to realize certain important but painful truths about their existence, they develop internal strength and control of their lives. Just as people learn to face their being, so can they come to terms with their non-being. According to the causal process in Buddhism, Human Being is not always annihilation of self. Therefore, birth, aging, disease and death go through the process of natural change and it is the appearance of human existence which is inherent in the health of every human being. To promote our health we must gain an insight about this phenomenon. This study viewed nurses' clients as 〈good friend〉 rather than 〈patient〉 which focuses on a disease-oriented concept. The concept of 〈good friend〉 views nurses' clients as active participants to create their life and as responsible persons in a constantly changing life. The study also examined the concept of recovery which means to come back to the previous healthy state and it suggested that the concept of recovery should be changed to 〈good change〉, because in existential philosophy, human beings are viewed as never going back to the past but moving on to the future by creating their existence. This study also suggested that nursing should help 〈good friend〉enlighten their existence to be free from pain and death and to get control over their existence.

• Journal of the Korean Operations Research and Management Science Society
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• v.41 no.2
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• pp.35-51
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• 2016

This paper proposes a new approximate approach to calculate the order fill rate and the probability of filling an entire customer order immediately from the shelf in a business environment under purchase dependence characterized by customer purchase patterns observed in such areas as marketing, manufacturing systems, and distribution systems. The new approximate approach divides customer orders into item orders and calculates fill rates of all order types to approximate the order fill rate. We develop a greed iterative search algorithm (GISA) based on the Gauss-Seidel method to avoid dimensionality and prevent the solution divergence for larger instances. Through the computational analysis that compares the GISA with the simulation, we demonstrate that the GISA is a dependable algorithm for deriving the stationary joint distribution of on-hand inventories in the type-K pure system. We also present some managerial insights.

• Journal of applied mathematics & informatics
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• v.33 no.1_2
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• pp.77-87
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• 2015

Parallel lines are often used to increase production rate in many manufacturing systems where the main line splits into several lines in parallel, and after some operations, they merge into a main line again. Queueing networks with finite buffers have been widely used for modeling and analyzing manufacturing systems. This paper provides an approximation technique for multi-server two-stage networks with merge configuration and blocking which will be a building block for analysis of general manufacturing systems with parallel lines and merge configuration. The main idea of the method is to decompose the original system into subsystems that have two service stations with multiple servers, two buffers and external arrivals to the second stage are allowed. The subsystems are modeled by level dependent quasi-birth-and-death (LDQBD) process.

• ETRI Journal
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• v.37 no.5
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• pp.917-921
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• 2015

We consider a multiserver system with two classes of customers with preemption, which is a widely used system in the analysis of cognitive radio networks. It is known that the optimal admission control for this system is of threshold type. We express the expected total discounted profit using the total number of customers, thus reducing the stochastic optimization problem with a two-dimensional state space to a problem with a one-dimensional birth-and-death structure. An efficient algorithm is proposed for the calculation of the expected total discounted profit.

• International Journal of Reliability and Applications
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• v.16 no.1
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• pp.35-53
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• 2015

This investigation deals with reliability and sensitivity analysis of a repairable embedded system with standby wherein repairman takes multiple vacations. The hardware system consists of 'M' operating and 'S' standby components. The repairman can leave for multiple vacations of random length during its idle time. Whenever any operating unit fails, it is immediately replaced by a standby unit if available. Moreover, governing equations of an embedded system are constructed using appropriate birth-death rates. The vacation and repair time of repairman are exponentially distributed. The matrix method is used to find the steady-state probabilities of the number of failed components in the embedded system as well as other performance measures. Reliability indexes are presented. Further, numerical experiments are carried out for various system characteristics to examine the effects of different parameter. Using a special class of neuro-fuzzy systems i.e. Adaptive Network-based Fuzzy Interference Systems (ANFIS), we also approximate various performance measures. Finally, the conclusions and future research directions are provided.

• Health Policy and Management
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• v.28 no.3
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• pp.222-225
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• 2018

Health policy is a historical product in the process of development, including the political and economic factors of the state as well as the social and cultural elements of the country. Bioethics began to debate the ethical questions that arise in the overall process of life's birth and death, and gradually evolved by presenting ethical directions for various social phenomena. Especially, according to the moral awakening of 'scientific medicine' which caused in some human problems in the rapidized scientific society from the late 19th century to the early 20th century, as a result of distress including the concept of various social relations, it is possible to say that it has reached the bioethics. Although health policy and bioethics are different in terms of starting and concept, they can be found in common with social, cultural, and political diversity in the times. In 2004, 'Bioethics Law' was enacted through the issue of research ethics in the life sciences. Therefore, in order to examine ethical aspects of current health policy direction and major issues, it can be divided into before and after enactment of 'Bioethics Law' in 2004. The authors would like to examine how the evolution of the ethical viewpoint on the health policy has changed in line with the enactment of the 'Bioethics Law' and how it is trying to solve it from an ethical point of view. Through the various events that took place in the 1990s and the 2000s, various discussions on bioethics were conducted in Korea. Prior to the enactment of the 'Bioethics Law,' ethical judgments of professions, distribution of healthcare resources, if the discussion focused on the ethical judgment of abortion, and the various events that appeared in the early 2000s became the beginning to inform that the ethical debate about the life, death, and dignity of human beings began in earnest in Korea with the enactment of the 'Bioethics Law.' Since then, 'Hospice and Palliative care Law' which was enacted in 2017, is based on the fact that the health policy of our country focuses on the treatment of the past diseases, health promotion, and delivery of health care services. It was an opportunity to let them know that even the quality problems were included. Therefore, considering the various circumstances, the ethical issue facing Korea's health care system in the future is the change of the demographic structure due to aging and what is to be considered as the beginning and the process of life in the overall process of life. It is the worry about how to die and when it sees as death. This has far exceeded the paradigm of traditional health care policies such as disease prevention and management and health promotion, and calls for innovative policy response at the national level that reflects the new paradigm, which in many cases creates a predictable ethical environment. And health policy should be shifted in the direction of future ethical review considering sustainability in the development process of future health care rather than coercive management.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.2
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• pp.134-141
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• 2008

This paper presents an innovative load management technique that can effectively lower the summer peak load by adjusting the aircondition loads through smoothe coordinations between utility companies and large customers. An intelligent hierarchical load management system composed of a Central Intelligent Load Management System(CIMS) and multiple Local Intelligent Management Systems(LIMS) is also proposed to implement the reposed technique. Upon receiving a load curtailment request from the utilities, CIMS issues tokens, which can be used by each LIMS as a right to turn on the airconditioner. CIMS creates and maintains a queue for fair allocation of the tokens among the LIMS demanding tokens. By adjusting the number tokens and queue management Policies, desired load factors can be achieved conveniently. The Markov Birth and Death Process and the Balance Equations are employed in estimating various queue performances. The proposed technique is tested using a summer load data of a large apartment complex and proved to be quite effective in load management while minimizing the customer inconveniences.