• Journal of the Korea Society of Computer and Information
• /
• v.13 no.7
• /
• pp.281-289
• /
• 2008

In this study, a discrete-event simulation model is developed to estimate load factors and the corresponding revenues under different pricing and dispatching policies. The model has been employed to forecast the inbound and the outbound air cargo demands of the major Northeastern Chinese cities, and the simulation results were compared to the actual demands obtained from real-life airline operations. The statistical analysis confirms that the simulation model is able to provide accurate estimates for air cargo demands, and thus, the model may be employed to be a useful tool for air cargo demand management.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.37 no.1
• /
• pp.60-67
• /
• 2014

This paper considers an inbound ordering and outbound dispatching problem for multi-products and multi-vehicles in a third-party distribution center. The demands are dynamic over a discrete and finite time horizon, and replenishing orders are shipped in various transportation modes and the freight cost is proportional to the number of vehicles used. Any mixture of products is loaded onto any type of vehicles. The objective of the study is to simultaneously determine the inbound lot-sizes, the outbound dispatching sizes, and the types and numbers of vehicles used to minimize total costs, which consist of inventory holding cost and freight cost. Delivery time window is one of the general dispatching policies between a third-party distribution center and customers in practice. In the policy, each demand of product for a customer must be delivered within the time window without penalty cost. We derive mixed integer programming models for the dispatching policy with delivery time windows and on-time delivery dispatching policy, respectively and analyze the effect on a dispatching policy with delivery time windows by comparing with on-time delivery dispatching policy using various computational experiments.

• Journal of Korean Institute of Industrial Engineers
• /
• v.37 no.4
• /
• pp.331-341
• /
• 2011

This paper considers an inbound lot-sizing and outbound dispatching problem for a single product in a thirdparty logistics (3PL) distribution center. Demands are dynamic and finite over the discrete time horizon, and moreover, each demand has a delivery time window which is the time interval with the dates between the earliest and the latest delivery dates All the product amounts must be delivered to the customer in the time window. Ordered products are shipped by multiple vehicle types and the freight cost is proportional to the vehicle-types and the number of vehicles used. First, we formulate a mixed integer programming model. Since it is difficult to solve the model as the size of real problem being very large, we design a conventional genetic algorithm with a local search heuristic (HGA) and an improved genetic algorithm called adaptive genetic algorithm (AGA). AGA spontaneously adjusts crossover and mutation rate depending upon the status of current population. Finally, we conduct some computational experiments to evaluate the performance of AGA with HGA.

• Journal of the Korea Safety Management & Science
• /
• v.10 no.2
• /
• pp.187-193
• /
• 2008

Cross docking is a warehouse management concept in which items delivered to a distribution facility by inbound trucks are immediately sorted out and reorganized based on customer demands and are routed and loaded into outbound trucks for delivery to customers without actually being held in inventory in the distribution facility. In this research, the design of distribution facility for cross docking systems was studied. The objective of this research is to find the minimum number of receiving docks and shipping docks, respectively, in order to meet the daily demand of the distribution center. Two solution approaches are employed in modeling and solving the problem The first approach is mathematical modeling and the second approach is a simulation. The logic developed in the simulation model is expected to apply to the real world situation.

• Economic and Environmental Geology
• /
• v.57 no.2
• /
• pp.161-175
• /
• 2024

Aggregate typically refers to sand and gravel formed by the transportation of rocks in rivers or artificially crushed, constituting a core resource in the construction industry. Gyeongsangbuk-do, the largest administrative area in South Korea, produces various sources of gravel, including forest, land (excluding other sources), river, and crushed stone. As of 2022, it has extracted approximately 6.96 million cubic meters of aggregate, with permitted production totaling around 4.07 million cubic meters and reported production of about 2.88 million cubic meters. The aggregate demand in Gyeongsangbuk-do is estimated to be 12.39 million cubic meters according to the estimation method in Ready-Mix Concrete. From the supply perspective, about 120 extraction sites are operational, with most municipalities maintaining an appropriate balance between aggregate demand and supply. However, in some areas, there is inbound and outbound transportation of aggregate to neighboring regions. Regions with significant inbound and outbound aggregate transportation in Gyeongsangbuk-do are areas connected to Daegu Metropolitan City and Pohang City along the Gyeongbu rail line, showing a high correlation with population distribution. Gyeongsangbuk-do faces challenges such as population decline, aging rural areas, and insufficient balanced regional development. Analysis using GIS reveals these trends in gravel demand and supply. Currently in this study, Gyeongsangbuk-do meets its demand for aggregate through the supply of various aggregate sources, maintaining stable aggregate procurement. River and terrestrial aggregates may be sustained as short-term supply strategies due to the difficulty of longterm development. Considering the reliance on raw material supply for selective crushing, it suggests the need for raw material management to maintain stability. Gyeongsangbuk-do highlights quarries in the forest as an important resource for sustainable aggregate supply, advocating for the development of large-scale aggregate quarries as a long-term alternative. These research findings are expected to provide valuable insights for formulating strategies for sustainable management and stable utilization of aggregate resources.

• International Area Studies Review
• /
• v.13 no.3
• /
• pp.413-438
• /
• 2009

Tourism is an attractive field of industry to many countries due to its strong potentials in increasing employment rates as well as improving the national image. The positive effect of the tourism on the national economy and globalization has been recognized in Korea. A multilateral effort has been made in order to develop its tourist industry. Therefore, it is necessary to analyze the patterns of tourism demand in Korea. The present study analyzes and demonstrates the effects of a nation's characteristics on tourism demand. The study model was based on factors that affected tourism demand, especially emphasizing on the economic size, distance, national income, and language differences from the mother country. In particular, this study highlights the effects of economic relations between the countries and their exchange rate on tourism demand. In summary, this thesis demonstrates that actual national and international panel data enhance the credibility of the research and precisely determine factors that have a direct influence on tourism demand. A corresponding strategy of development and products are required as most tourists show the preference in advanced nations.

• Management & Information Systems Review
• /
• v.36 no.2
• /
• pp.81-92
• /
• 2017

This study was to investigate the elasticity in tourism demand of Chinese tourists visiting Malaysia through ARDL models by using Chinese tourists arrivals, GDP, CPI, transportation costs and others. When China was implementing an open-door policy with foreign countries in the early 15th century, the movement of Chinese was very limited, and then communication between China and other countries was very weak. However, the Chinese government persistently and entirely implemented an open-door policy by participating in the World Trade Organization(WTO) in 2001. The Chinese government has opened the economy through foreign direct investment by providing various incentives for foreign investment. As a result, inbound and outbound Chinese movements increased in the early 21st century. China was one of the top five most visited tourist destinations in the world by 2016, and also Chinese tourists traveling abroad increased, so they made Malaysia a popular tourists destination because of increase sharply to around 1.41 million. This study examined the significance of major economic factors affecting the increase in Chinese tourists arriving in Malaysia. Other factors that induced their arrival included income, tourism prices, transportation costs and promotional activities. Short-run shocks from the Asian economic crisis and the outbreak of SARS were included to understand how tourism demand in Malaysia was affected. Finally this study found that the combination of the ARDL and the Error Correction Model were useful to statistically estimate the elasticities of tourism demand.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.11
• /
• pp.4268-4290
• /
• 2015

Future mobile communications face enormous challenges as traditional voice services are replaced with increasing mobile multimedia and data services. To address the vast data traffic volume and the requirement of user Quality of Experience (QoE) in the next generation mobile networks, it is imperative to develop efficient content distribution technique, aiming at significantly reducing redundant data transmissions and improving content delivery performance. On the other hand, in recent years cloud computing as a promising new content-centric paradigm is exploited to fulfil the multimedia requirements by provisioning data and computing resources on demand. In this paper, we propose a cooperative caching framework which implements State based Content Distribution (SCD) algorithm for future mobile networks. In our proposed framework, cloud service providers deploy a plurality of cloudlets in the network forming a Distributed Cloud Service Network (DCSN), and pre-allocate content services in local cloudlets to avoid redundant content transmissions. We use content popularity and content state which is determined by content requests, editorial updates and new arrivals to formulate a content distribution optimization model. Data contents are deployed in local cloudlets according to the optimal solution to achieve the lowest average content delivery latency. We use simulation experiments to validate the effectiveness of our proposed framework. Numerical results show that the proposed framework can significantly improve content cache hit rate, reduce content delivery latency and outbound traffic volume in comparison with known existing caching strategies.

• Journal of Navigation and Port Research
• /
• v.29 no.5 s.101
• /
• pp.439-445
• /
• 2005

Recently, owing to the increasing demand on the simplification of arrival and departure procedures, IMO's (International Maritime Organization) Facilitation Committee (FAL) is carrying out the standardization project of arrival and departure formalities and clearance form. Also, many port authorities of developed countries are making active researches for the smooth flow and efficiency of the information inbound and outbound ships by way of simplifying their formalities or through electronic means. However, this standardization project cannot be done by one country but by mutual cooperation among related nations. And to carry out this task, the first thing to be done is to standardize the formalities and document form, and to integrate information. To this end, this study has reviewed the model cases of advanced ports of developed countries with regard to their simplification and standardization efforts. And also we have analyzed the formalities and clearance form of the three countries Korea, China, and Japan. And then for the solution of common problems of three countries, this paper has suggested an ebXML-based Global Port B2B framework. Through this framework, we can reuse and automate the necessary information on the arrival and departure of ships, consequently realizing simplification, and laying a foundation for the introduction of e-commerce to the port industry.

• Journal of the Korean Geographical Society
• /
• v.42 no.4
• /
• pp.526-539
• /
• 2007

The purpose of this study is to investigate the influence of the Korean Wave on Chinese tourism to South Korea through a behavioral analysis of Chinese tourists in the general group package tours. China suppressed the needs of the Chinese people's geographical movement and imposed restrictions on information about the outside world with the use of a policy of "closure" for a long time. But since reforms and open-door policies were introduced in China, especially in the context of relaxation of control policies over Chinese outbound tourism after the mid-1990's, more and more Chinese make trips abroad including visits to South Korea. In this situation, the recent Korean Wave(especially, drama/film) describes the Korean national image by forming a bridge between fiction and reality and plays a pivotal role in broadening or reconstructing the geographical imagination of the Chinese people who have been historically isolated from the outside world. Although Chinese have imagined the Korean nationscape on the basis of geopolitical or economic factors in the past, they have currently broadened or reconstructed their geographical imagination to include socio-cultural factors related closely to the Korean way of life due to the recent Korean Wave. This newly constructed geographical imagination led by the Korean Wave functions as an important pulling factor in Chinese destination choices, affecting Chinese tourists' motivation formation and the recommendation of main attractions. The more influential the Korean Wave is on their destination choice, the more the respondents select the cultural factors in both their motivation for tourism to South Korea and their recommendations of tourism attractions to other people. Through the analysis results of both satisfaction and intention to revisit, the more influential the Korean Wave is on their destination choice, the higher is the degree of both satisfaction and intention to revisit. In other words, although Chinese tourism to South Korea is chiefly in the general group package tours, Chinese tourists who are influenced by Korean Wave on their destination choice have more attachment to(or affection for) Korea as a tourism destination. This result suggests that the Korean Wave affects qualitative change - that is, change of attitude - as well as quantitative change in Chinese demand for tourism to South Korea.