• 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.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.06a
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• pp.74-76
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• 2013

컨테이너 터미널은 비용 절감과 생산성 향상을 위해 무인 야드 크레인을 운영하고 있다. 그러나 무인 야드 크레인이 상하차 작업을 안전하고 원활하게 수행하기 위해서는 작업자의 원격 통제가 필요하다. 상하차 작업은 다수의 야드 크레인에게 불규칙적으로 발생하며 다수의 원격 통제 작업자들은 교대로 작업 요청을 배정받아 원격 작업을 수행한다. 본 연구는 상하차 작업의 적정 서비스 수준을 고려하여 작업인력 비용과 대기비용의 합을 최소화하는 인력 산정 방법을 다루었다. 대기이론을 이용하여 원격작업 인력과 비용 요소의 변화에 따른 작업대기를 분석하였다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1996.07a
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• pp.89-102
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• 1996

본 연구는 우리나라 대기오염의 실태를 알아보고, 급격히 증가하고 있는 대기오염으로 인한 사회적 비용을 산출해 봄으로서 비용-편익분석에 기초하여 이루어지고 있는 선진국형 환경규제기준의 발판을 마련하는데 그 의의가 있다. 이러한 연구는 앞으로 WTO의 정식의제로 채택되리라고 예상되는 환경정책에 능동적으로 대응하고, 우리나라 환경정책의 우선순위의 결정 및 사람들이 체감으로 느끼는 대기오염의 심각성을 확인시킴으로써 환경보전에 대한 인식을 확산, 환경정책의 수행을 용이하게 한다. 이산화질소와 호흡기 질환의 반응도에 관한 실증분석의 결과는 이산화질소가 인체의 호흡기 질환에 매우 유의적인 영향을 미치고, 이산화질소 대기오염으로 인한 한해 동안의 사회적 비용은 약 5조 3,946억원을 상회했다. 이외에 상관관계를 이용해 대기오염이 질병에 미치는 영향을 진료과목별로 분류하여 분석한 결과는 대기오염이 질병에 상당한 상관관계를 갖고 질병을 유발시키고 있음을 확인했다.

• Journal of Korea Port Economic Association
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• v.26 no.3
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• pp.42-55
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• 2010

This paper primarily deals with a decision-making for determining the number of voyages in each ship size under a specific port structure in order to minimize the total transport cost consisting of transport cost at sea, queuing cost in port, and inventory cost in yard. As a result of computer simulation using queuing model characterized by inter-arrival time distribution, we were able to find out some combination of voyage numbers of 3 ship-size(50,000-ton, 100,000-ton, and 200,000-ton), where the total transport cost can be minimized under a specific port structure. The simulation model also allows us to figure out any trade-off relationship among sea transport cost, queuing cost in port, and inventory cost in yard. Put it differently, an attempt to reduce the sea transport cost by increasing the number of voyages of the largest ship size, the transport cost incurred in both port and yard is hypothesized to be increased and vice versa. Consequently, Port managers are required to adjust the number of annual number of voyages allocated in each ship size, put into the sea lines for importing raw materials, in order to optimize the transport costs incurred under the specific port system. We may consider a net present value(NPV) model for performing an economic feasibility analysis on port investment project. If a total discounted net benefit, including cost savings, exceeds the initial investment for an additional berth construction, then we accept the port investment project. Otherwise, we reject the proposed port investment plan.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1087-1094
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• 2013

This study aims at enhancing the objective estimation of social cost of air quality due to mobile emission. More specifically, it examines the difference between the daily oriented and hourly oriented estimation results of social air quality cost and draws implications from the comparative analysis. The result indicates that the social cost of air quality differs up to approximately 24 times depending on the analysis time period. Moneywise, the difference between daily and hourly assignments amounts to the average of 653.5 billion won whereas only 1% of error occurred in the estimation result based on peak and nonpeak based hourly assignment. This study reaffirms the need for time-based travel demand management for emission reduction, and confirms the feasibility of emission estimation by travel demand forecasting method over the conventional method employed by the CAPSS.

• Environmental and Resource Economics Review
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• v.6 no.1
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• pp.111-128
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• 1996

본 연구는 대기오염물질인 이산화질소와 인체의 호흡기질환과의 반응도를 실증분석하고, 이 반응도를 이용해 이산화질소의 대기오염으로 인한 사회적 비용을 계산하는 것이다. 사람들이 대기오염에 노출되었을 때 발생하는 질환의 피해를 측정하기 위하여 손실함수(damage function)를 설정하고, 이를 회귀분석기법(regression technique)을 이용해 추정한 결과 이산화질소는 호흡기질환에 상당히 유의적인 영향을 미쳤고, 1994년 한해 동안 배출된 이산화질소량이 발생시킨 사회적 비용은 약 8조 2천 억원이었다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.29 no.3
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• pp.70-78
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• 2006

제조업에서는 보다 합리적으로 생산량을 결정함으로써 고객에 대한 납기 준수는 물론, 기업 내부의 비용을 감소시키기 위한 노력을 끊임없이 하고 있다. 합리적인 생산량의 결정은 기업 내적으로는 낭비를 제거하고, 생산 흐름의 안정성을 유지하여 주며, 기업 외적으로는 공급사슬 전체의 자재흐름을 원활히 해주고 고객의 기호 변화에 빠르게 대처할 수 있도록 한다. 이에 본 논문은 보다 높은 고객 만족도와 비용의 절감을 위해서 재고 유지비용과 생산준비비용만을 고려하는 기존의 생산량 결정 모형에 고객의 대기 비용을 추가한 다품목 경제적 생산량 모델을 제시하였다.

• Journal of Korea Port Economic Association
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• v.29 no.3
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• pp.159-174
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• 2013

This paper mainly deals with the appropriation of ship voyage allocation, using a heuristic regression model, in order to reduce total costs incurred in port, yard and at sea under the specific port condition. Because of different behavior of costs incurred in port, yard and at sea, an effort to minimize these costs by adjusting the number of voyages for three ship classes(50,000, 100,000, and 150,000-ton) should be made. For instance, if the port managers attempt to reduce the sea transport cost by increasing the annual allocated number of ship voyages classed 150,000-ton for economies of scale, they have no choice but to suffer a significant increase in queueing cost due to port congestion. To put it differently, there are trade-off relationships among the costs incurred in port, yard, and at sea. We utilized a computer simulation result to perform a couple of regression analyses in order to figure out the appropriate range of allocated number of voyages of each ship class using a heuristic approach. The detailed analytical results will be shown at the main paper. We also suggested a net present value(NPV) model to make a proper investment decision for an additional berth of 200,000-ton class that alleviates port congestion and reduces transport cost incurred both in port and at sea.

• 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 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.