• Journal of Digital Convergence
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• v.15 no.10
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• pp.31-43
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• 2017

This study was aimed at analyzing the operational efficiency of DPAs(the delivery and pickup agents), which serve as sub-terminals in parcel delivery services, using CCR/BCC models in DEA. The input variables included the number of employees, and the amount of equipment and the operating expenses. The output variable was revenue value. The efficiency for the period from 2014 to 2016 was analyzed. The results revealed that the operational efficiency improved in 2016, compared with 2014, in both CCR and BCC models. According to the benchmarking analysis, DMU 1 and DMU 7 showed higher efficiency in 2016. The inefficiency analysis based on the BCC model showed increased efficiency of all factors in 2016 when compared with 2014. The Malmquist productivity index (MPI) dropped slightly as a result of technical changes and indicated a declining technical efficiency in all DMUs. This study suggests the need for government-led systematic improvement and support for DPAs by providing current insight into the parcel delivery industry and analyzing DPAs' operational efficiency in Korea for the first time. This research performed efficiency analysis of DPAs located in new town of paju and gimpo cities. In future research, comparative study on efficiency analysis including new town, old town area, and other cities are needed.

• Journal of Korean Society of Transportation
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• v.36 no.3
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• pp.169-183
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• 2018

Aggressive driving leads to a greater crash potential because it threatens surrounding vehicles. This study conducted traffic simulation experiments using driving behavior data obtained from multi-agent driving simulations. VISSIM traffic simulator and surrogate safety assessment model (SSAM) were used to identify the impacts of aggressive driving on traffic stream in terms of safety and operational efficiency. Market penetration rates (MPR) of aggressive driving vehicle, coupled with various traffic conditions, were taken into consideration in analyzing the impacts. As expected, it was identified that aggressive driving vehicles tended to deteriorate the traffic safety performance. From the perspective of operational efficiency, interesting results were observable. Under level of service (LOS) A, B, and C, it was observed that the average travel speed increased with greater MPRs. Conversely, the average travel speed decreased with under LOS D and E conditions. The outcome of this study would be effectively used for developing safety-related policies for reducing aggressive driving behavior.

• Journal of the Korean Society for Railway
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• v.15 no.5
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• pp.524-530
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• 2012

Recently, open access policy to railway operation has been widely discussed. Compared to the case of Korea, European countries have dealt with this topic over a few decades. The competition on railway slots incurs an important technological problem about how to optimally allocate railway slots requested from RUs to them. In other words, the authority should be able to coordinate the timetables requested from RUs in the non-discriminatory manner. Related with the coordination, compared to the other European countries, which have done many studies and experiments especially on auction mechanisms, Korean railway has paid less attention to this topic and there have not been any related studies. Our study analyses the state-of-the-arts about the railway slot allocation especially focusing on the auction mechanisms and the associated optimization problems. And we suggest a new railway slot allocation mechanism and related optimization model reflecting the adjustment within the tolerance and the operational policies between railway undertakings.

• Journal of Korean Institute of Industrial Engineers
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• v.35 no.1
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• pp.58-72
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• 2009

The main activities of container terminals are to load container freights to vessels, discharge them from vessels, and store them in the storage yard. Container terminals make many operational plans to execute these functions effectively. If the plans do not consider enough the loads of related resources, they may have low actualities. This study discusses the optimal yard planning model which considers various resources, such as the storage yard, yard cranes, internal vehicles, and travel lanes, in container terminals. The model determines the groups and amounts of containers which are stored in each storage block by using the resource profile. The yard planning problem is represented to the multi-commodity minimal cost flow problem and is formulated to the linear programming model. In order to explain the application of the mathematical model, the numerical examples are presented. Additionally, the relationship between the average load ratio and the relocation ratio is discussed.

• Journal of the Korea Safety Management & Science
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• v.8 no.5
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• pp.167-180
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• 2006

This study expands limitation of OASIS(Optimal Allocation of Spares for Initial Supports) program, which calculates CSP(Concurrent Spare Part), not only availability but also cost, and developed the program enabling run in WINDOW OS. By considering multi-step repair and logistics support system, repairing capability at the time of deployment, and procurement period, this model is the first local model reflecting circumstances of the armed forces of the Republic of Korea. Furthermore, the programmed model was selected as the military standard software and has being essentially used for CSP calculation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.11a
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• pp.53-61
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• 2002

This paper aims to apply a supply chain modeling and its analysis framework to the supply chain in the port industry, each of which has its own objective. The simulation approach serves two purposes: to model a supply chain network in quantity approach and to evaluate its supply chain performance based on proposed strategies. The simulation model will be applied to quantifying the flow of a supply chain, the involved information and material flow and conducted to simulate the supply chain operations. The model will also be used which strategic and operational policies are the most effective in smoothing the variations in the supply chain.

• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.477-487
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• 2020

The inefficient operation of Busan New Port is due to container-terminal operators being dispersed in small groups, rather than being integrated. This dispersion increased following the reorganization of global shipping alliances in 2016 and causes unnecessary Inter-terminal Transportation(ITT) and ship delays. Studies of integrated operations for larger container terminals show that integration is not going well, however, due to the pre-emptive task that follows the integrated operation. Therefore, in this study, we divided the integrated operation into stages based on a simulated model of the container terminals in Busan New Port. The simulation took into account future increases in the ship's enlargement and terminal congestion, and the operational effects of each type of integrated operation were analyzed and evaluated.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.4
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• pp.238-247
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• 2018

This paper considers the problem of scheduling loading and unloading operations of a crane in a railway terminal motivated from rail-road container transshipment operations at Uiwang Inland Container Depot (ICD). Unlike previous studies only considering the total handling time of containers, this paper considers a bi-criteria objective of minimizing the weighted sum of the total handling time and tenant service time. The tenant service time is an important criterion in terms of terminal tenants who are private logistics companies in charge of moving containers from/to the terminal using their trucks. In the rail-road container shipment yard, the tenant service time of a tenant can be defined by a time difference between beginning and finishing loading and unloading operations of a crane. Thus, finding a set of sequences and time of the crane operations becomes a crucial decision issue in the problem. The problem is formulated as a nonlinear program which is improved by linearizing a nonlinear constraint in the model. This paper develops a genetic algorithm to solve the problem and performs a case study on the Uiwang ICD terminal. Computational experiment results show that the genetic algorithm shows better performance than commercial optimization solvers. Operational implications in terms of tenants are drawn through sensitivity analyses.

• Journal of Distribution Science
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• v.15 no.11
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• pp.59-72
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• 2017

Purpose - This paper evaluated the efficiency performance of the three major maritime transport markets and examined the determinants of the performance. The firms' revenue fluctuates with the changes of the economic cycle; hence it is important for them to set up business strategies to improve efficiencies. A lack of efficiency measurements for shipping firms leads to a significant gap in determining their overall performance. Research design, data, and methodology - Each of DEA scores was adopted for the evaluation and panel regression was used to examine the impact of determinants on the performance. The analysis included 50 shipping firms from three maritime transport markets as follows; 15 firms of container liners, 18 firms of bulk carrier and 17 firms of tanker carriers, and its period was from 2010 to 2016. Results - In the CCR model, container liners were the highest, tanker carriers were the second, and bulk carriers were the lowest in operation efficiency and financial efficiency. By region, operation efficiency and financial efficiency was high in the order of America, Asia, and Europe. Conclusions - This study suggests business strategies for maritime transport companies based on the analytical results of determinants of operational and financial efficiency.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.1
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• pp.181-186
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• 2022

There is a demand for an intermodal automatic transport bogie as a means for efficient logistics transport. Intermodal is characterized by high demand for single-track operation in a specific section in connection with heterogeneous transportation means. In this study, a driving information system that is simple and optimized for the intermodal automatic transportation bogie is implemented to be suitable for the characteristics of the inter-modal automatic transportation bogie, unlike the existing railroad operation system, and applied to a real large-scale demonstration model to ensure in-place stopping and a smooth interface between each system. and operational examples with a simplified system.