• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.27-29
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• 2017

Container terminals in Northern Vietnam have recorded an impressive development in recent years. This development, however, also raises a fierce competition among local container terminals to attract customers. Beside the handling charges, the vessels' waiting cost is also an important factor that drive the opinion of users in choosing appropriate terminal. This research plans to estimate the waiting cost in different container terminals in Northern Vietnam by building regression equation that describe the relationship between the rate of throughput/capacity and waiting cost/TEU. Queuing theory with the application of Poisson distibution is used to estimate the waiting time of arrival vessels and uncertainty theory is applied to estimate the vessel's daily expenses. Previous studies suggested two different formation of the equation and according to the research results, cubic equation is more suitable in the given case. The research results are also useful for further research which require calculation of waiting cost per TEU in each container terminal in Northern Vietnam.

• Journal of Distribution Science
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• v.7 no.2
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• pp.45-61
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• 2009

The aims of this paper is to examine the key factor of customer satisfaction in the medical service. Especially service waiting is a significant component of the customer's overall satisfaction with the service process. For this purpose, this study proposed 6 hypotheses as follow : H1 : Waiting cost, affect on perceived service waiting, will be different between patient customer group and health care group. H2 : Controllability of the cause, affect on perceived service waiting, will be different between patient customer group and health care group. H3 : Controllability of the cause affect on perceived service waiting, will be different between patient customer group and health care group. H4 : Waiting environment, affect on perceived service waiting, will be different between patient customer group and health care group. H5 : Transaction importance, affect on perceived service waiting, will be different between patient customer group and health care group. H1 : Waiting cost, Controllability of the cause, Controllability of the cause, Waiting environment, Transaction importance, customer satisfaction will affect on service waiting significantly This study find that 1) Waiting cost and Transaction importance are significant variables to influence customer satisfaction between patient group and health care group. 2) customer satisfaction is very important variables to minimize perceived service waiting.

• Journal of Korea Port Economic Association
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• v.25 no.4
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• pp.183-202
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• 2009

This study estimates the port waiting cost of international trade ports in Korea by an opportunity cost approach. In the next step, we present a method to assess the levels of port services by the average waiting cost of ships derived from the results of the first step. Because the port waiting cost reflects the social cost, it is difficult to use as a service indicator even though it is the decision support information for a particular port facility expansion. The percentages of waiting ships and time also are insufficient indicators to reflect only the quantitative aspects by the time. However, the average waiting cost of ships in this study can be utilized as a service indicator to reflect waiting time and the loss of economic value simultaneously. It is also very useful information for a shipper and a carrier to select a port. Based on the average waiting cost of ships in 2007, it is analyzed in order of lowest service ports sequentially such as Pyeongtaek-Dangjin, Pohang, Donghae, and Samcheonpo. It is different from the sequential order of ports by the port waiting cost such as Pohang, Incheon, Gwangyang, Pyeongtak-Dangjin, and Ulsan. The port waiting cost is to a port authority as a key indicator what the average waiting cost of ships is to a port user as a useful indicator to evaluate the levels of port services.

• Journal of the Korea Society for Simulation
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• v.3 no.1
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• pp.99-105
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• 1994

Most of the companies are forced to cut down the manufacturing cost to survive in the competitive environment. Among others, material distribution cost alone takes substantial portion of the total manufacturing cost. In this study, we investigate the waiting phenomenon in the toll gate and propose a new toll booth layout to reduce the waiting time, thereby reduce the total material distribution cost. SIMAN, a simulation language, is employed to evaluate the proposed layout. The experimental results show that the layout reduces the waiting time significantly. Furthermore, the result indicates that determination of the intermediate buffer space affects the performance of the proposed layout.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.1
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• pp.27-33
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• 2019

Several studies have been completed on the topic of container terminals in Northern Vietnam. Few of them, however, deal with competition in terms of costs related to vessel waiting time or cargo handling. This paper estimates the average waiting cost per TEU for all the container terminals in Northern Vietnam. After average waiting time was first estimated by applying queuing theory, uncertainty theory was applied to estimated vessel daily cost. A simulation was performed to create a series of data representing waiting cost per TEU in relation to the rate of volume handled/capacity of each terminal. Non-linear regression based on this series was used to present a function for the relationship between the average waiting cost of each terminal and the rate of volume handled /capacity.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.6 no.8
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• pp.93-103
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• 1983

In this paper, we study an optimal service policy of the M/M/2/K queueing system with two types of customers. The incurred costs consist of waiting cost, service cost and incurred costs consist of waiting cost, service cut and changeover cost. The changeover cost occurs when a server who assigned to serve a particular type of customers reassigned to the other types of customers. Two servers serve two types of customers who arrive to the two separate queues. The two types of customers differ in respect of their arrival rate, service rate, waiting cost, and service cost. The servers require a policy, for determining when they should change their service type, which minimizes the long run expected total cost. The policy is obtained by a Markov decision process model that consists of a finite number of states and actions. In order to find the optimal service policy, we define states and actions of the system, compute onestep transition probabilities, and apply to the successive approximations algorithm.

• Journal of KIBIM
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• v.8 no.3
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• pp.31-42
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• 2018

This study focuses on the BIM request for information(RFI) processing performance and quantitatively analyzes the performance of the BIM coordinator and the loss due to the waiting of the project participants. For these purposes, a method to quantitatively evaluate the performance of the BIM coordinator was proposed using a queueing model. For the verification, two projects in which BIM was applied in the construction phase were selected, and the BIM RFI data were collected through the analysis of the BIM monthly report and BIM coordinator work log of each project. In addition, the BIM input personnel, labor cost, and productivity data were collected through interviews with the experts of the case projects. The analysis of the BIM RFI processing performance of the BIM coordinator using the queueing model exhibited on a probabilistic basis that the waiting status of the project participants could vary depending on the preliminary BIM application to the design verification as well as the input number and level of the BIM coordinator personnel. In addition, the loss cost due to the waiting of the project participants was analyzed using the number of BIM RFIs waiting to be processed in the queueing system. Finally, the economic feasibility analysis for the optimal BIM coordinator input was performed considering the loss cost. The results of this study can be used to make decisions about the optimal BIM coordinator input and can provide grounds for the BIM return on investment (ROI) analysis considering the waiting cost of the project participants.

• International Journal of Reliability and Applications
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• v.3 no.4
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• pp.165-171
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• 2002

An optimization of the M/M/1 queue with impatient customers is studied. The impatient customer does not enter the system if his or her virtual waiting time exceeds the threshold K ＞ 0. After assigning three costs to the system, a cost proportional to the virtual waiting time, a penalty to each impatient customer, and also a penalty to each unit of the idle period of the server, we show that there exists a threshold K which minimizes the long-run average cost per unit time.

• Spatial Information Research
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• v.22 no.5
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• pp.65-75
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• 2014

Bus headway plays an important role not only in determining the passenger waiting time and bus service quality, but also in influencing the bus operation cost and passenger demand. Previous research on headway control has considered only an hourly difference in the distribution of ridership between peak and non-peak hours. However, this approach is too simple to help manage ridership demand fluctuations in a short time scale; thus passengers' waiting cost will be generated when ridership demand exceeds the supply of bus services. Moreover, bus ridership demand varies by station location and traffic situation. To address this concern, we propose a headway control algorithm for minimizing the waiting time cost by using Smart Card data. We also provide proof of the convergence of the algorithm to the desired headway allocation using a set of preconditions of political waiting time guarantees and available fleet constraints. For model verification, the data from the No. 143 bus line in Seoul were used. The results show that the total savings in cost totaled approximately 600,000 won per day when we apply the time-value cost of waiting time. Thus, we can expect that cost savings will be more pronounced when the algorithm is applied to larger systems.

• Korean Management Science Review
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• v.25 no.2
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• pp.57-71
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• 2008

We study factors that affect consumers' switching behaviors among service providers in Korean mobile telecommunications service market. For empirical analysis, quarterly time series data from the first quarter of 2004 through the second quarter of 2007 were used. We chose the number of switchers to each mobile service provider in each quarter as dependent variables. Independent variables include acquisition costs per subscriber, which play the role of subsidy to mobile handset, switching costs, time trend, structural change effect, and waiting demand effects. Through the empirical analysis, we found that each provider's churn-in customers are affected by different factors. Specifically, the number of churn-in customers into SK Telecom is explained mainly by SK Telecom's customer acquisition costs and waiting demand from KTF, while the number of customers switching into KTF is better explained by switching costs from the previous service provider and waiting demand from SK Telecom. Those who chose LG Telecom as their new provider, on the other hand, were mainly attracted by LG Telecom's high subscriber acquisition cost.