• Journal of Korean Society of Industrial and Systems Engineering
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• v.9 no.13
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• pp.29-32
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• 1986

A decision procedure to determine when computer software should be released after testing is described. This paper extends optimum release policies minimizing the total expected software cost with a scheduled software delivery time under reliability requirement constraint. Such cost considerations enable us to make a release decision as to when transfer a software system from testing phase to operational phase. The underlying model is software reliability growth model described by a nonhomogeneous poisson process. It is assumed that the penalty cost function due to delay for a scheduled software delivery time is linearly proportional to time. Numerical examples are shown to illustrate the results.

• Communications for Statistical Applications and Methods
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• v.11 no.3
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• pp.631-641
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• 2004

In this paper, a model for an inventory whose stock decreases with time is considered. When a deliveryman arrives, if the level of the inventory exceeds a threshold $\alpha$, no stock is delivered, otherwise a delivery is made. It is assumed that the size of a delivery is a random variable Y which is exponentially distributed. After assigning various costs to the model, we calculate the long-run average cost and show that there exist unique value of arrival rate of deliveryman $\alpha$, unique value of threshold $\alpha$ and unique value of average delivery m which minimize the long-run average cost.

• Journal of Construction Engineering and Project Management
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• v.2 no.4
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• pp.25-31
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• 2012

The growing rate of delays is adversely affecting the timely delivery of construction projects. This study therefore assesses construction stakeholders' perception of the causes of delays and its effects on project delivery in a bid to proffer solution in minimizing the occurrences of delays. Questionnaire was used to elicit responses from construction stakeholders; a total of thirty three causes of delays, seventeen resultant effects of delays and fifteen methods of minimizing construction delays were identified for the study based on literature reviews. The results suggest that client's cash flow related problems are the main causes of delays while time and cost overruns are the major identifiable effects of delays in construction projects. However, adequate project planning and budgeting were suggested as possible ways of minimizing the occurrences of delays.

• Health Policy and Management
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• v.29 no.3
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• pp.248-261
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• 2019

Establishing a healthcare delivery system is key to building a cost-effective healthcare system that can prevent the waste of healthcare resources and increase efficiency. Recently, the rapid increase in the national medical expenditures due to the aging of the population and the increase in chronic diseases has raised the question about the sustainability of the healthcare system including the health insurance system. This is why we need to reform the medical delivery system, including the function setting of medical institutions. Accordingly, gradual and practical efforts based on the recognition of reality are needed for solving the problems and improving the medical delivery system. The first effort is to secure policy measures to establish functions and roles of medical institutions which are the basis of the healthcare delivery system, and a systematic medical use system for appropriate medical use. This approach can be achieved through a reasonable health insurance schemes. Without reasonable reform efforts, it will be difficult for Korea's health care system to develop into a system that can provide cost-effective and high-quality medical services that the people want.

• The KSFM Journal of Fluid Machinery
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• v.16 no.3
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• pp.48-53
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• 2013

Due to the urbanization, lots of people are living in cities. It is very convenient to live in the cities for the people but at the same time, the highly populated city has several environmental problems. During delivery process of large amount of municipal waste generated from the cities, the automobile emission and traffic jam have been occurred. The waste collection in the cities has been mainly done by using labour force and delivery truck. This is the conventional waste collection up to now. Recently, new technologies like automated waste collection system and capsule transportation have been introduced. Conventional waste collection mainly relied on the labour force and truck delivery does not need to invest a lot of money for the start-up. However, it requires to pay the operational cost both for the labour force and the truck delivery. On the contrary to this conventional waste collection, the automated waste collection and capsule transportation require high initial investment cost. However, the automated waste collection and capsule transportation can reduce significantly the pollutants emission, traffic jam by the waste trucks and actual waste collection cost per ton. In dealing with the waste collection in the cities, new waste collection technologies could be properly combined with the conventional waste collection for the effective municipal waste treatment.

• Journal of Communications and Networks
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• v.14 no.3
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• pp.319-335
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• 2012

In this study, we design an applicable model enabling internet protocol television (IPTV) service providers to use a virtual network (VN) for IPTV service delivery. The model addresses the guaranteed service delivery, cost effectiveness, flexible control, and scalable network infrastructure limitations of backbone or IP overlay-based content networks. There are two major challenges involved in this research: i) The design of an efficient, cost effective, and reliable virtual network topology (VNT) for IPTV service delivery and the handling of a VN allocation failure by infrastructure providers (InPs) and ii) the proper approach to reduce the cost of VNT recontruction and reallocation caused by VNT allocation failure. Therefore, in this study, we design a more reliable virtual network topology for solving a single virtual node, virtual link, or video server failure. We develop a novel optimization objective and an efficient VN construction algorithm for building the proposed topology. In addition, we address the VN allocation failure problem by proposing VNT decomposition and reconstruction algorithms. Various simulations are conducted to verify the effectiveness of the proposed VNT, as well as that of the associated construction, decomposition, and reconstruction algorithms in terms of reliability and efficiency. The simulation results are compared with the findings of existing works, and an improvement in performance is observed.

• Korea Journal of Hospital Management
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• v.14 no.2
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• pp.60-74
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• 2009

This study purports to verify managerial effectiveness of the integrated delivery system(IDS) of Japanese health care institutions through comparing the managerial performance between hospital groups providing with both acute and nursing care and those with acute care only. Data on the managerial performance of 697 hospitals providing with nursing care together and 819 hospitals providing with acute care only were collected from Japanese Central Social Insurance Medical Councils 2001, 2003, 2005, and were analyzed using mean comparison test(t-test) between the two groups. The results revealed that there were significant differences between the two groups in such indicators as ratio of material cost, labor cost, depreciation rate, total margin, operating margin, average number of outpatient per day, average revenue of an inpatient per day, total amount of labor cost, gross revenue per employee, and labor productivity. However, we could not find out any consistent evidence which support the effect of integrated delivery system on the hospital managerial performance. Further discussion was made on the limitation of the study and future research agenda relevant to the topic.

• Journal of Korean Institute of Industrial Engineers
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• v.40 no.4
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• pp.435-441
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• 2014

This paper considers a single-product problem for inbound lot-sizing and outbound dispatching at a third-party warehouse, where the demand is dynamic over the discrete time horizon. Each demand must be delivered into the corresponding delivery time window which is the time interval characterized by the earliest and latest delivery dates of the demand. Ordered products are shipped by heterogeneous container types. Each container type has type-dependent carrying capacity and the unit freight cost depends on each container type. Total freight cost is proportional to the number of each container type used. Also it is assumed that related cost functions are concave and backlogging is not allowed. The objective of the paper is to simultaneously determine the optimal inbound lot-sizing and outbound dispatching plans that minimize total costs which include ordering, shipping, and inventory holding costs. The optimal solution properties are characterized for the problem and then a dynamic programming algorithm is presented to find the optimal solution.

• Journal of Korea Society of Industrial Information Systems
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• v.26 no.6
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• pp.35-46
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• 2021

This study investigates the behavior of users using delivery apps as non-face-to-face lifestyles accelerated due to the 4th industrial revolution era and Covid 19. Specifically, this study examines the effect of customers' perceived service quality on the conversion cost, customer satisfaction, and continuous use intention. Based on the results, the main purpose of this study is to provide useful information and implications for entrants (restaurants) who have signed up and operated and platforms that connect customers, restaurants, and delivery people.

• Journal of the Korea Society of Computer and Information
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• v.14 no.4
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• pp.59-67
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• 2009

In wireless sensor networks (WSNs), geographic greedy forwarding fails to move a packet further towards its destination if the sender does not have any closer node to the destination in its one hop transmission region. In this paper, we propose a enhanced geographic routing, called CGR(Cost based Geographic Routing) for efficient data delivery against void problem environment. CGR first establishes Shadow Bound Region and then accomplishes Renewing Cost Function Algorithm for effective greedy forwarding data delivery. Our simulation results show significant improvements compared with existing schemes in terms of routing path length, success delivery ratio and energy efficiency.