• Journal of Navigation and Port Research
• /
• v.41 no.3
• /
• pp.149-154
• /
• 2017

Recently, container terminal operators have made efforts to develop an efficient remarshalling plan in response to the increase in automation of equipment handling and transport of containers in the terminals. Usually, containers are handled by multiple AYCs(automated yard cranes) in-yard in an automated container terminal, and terminal operators establish a remarshalling plan using slack time to increase the efficiency of ship operation. This study develops the optimal mathematical model through mixed integer programming as a solution to the problem of dispatching multiple AYCs. Considering the difficulty of direct application to the field due to computation time, we analyze the five prototypical dispatching rules for real world adaptation. A numerical experiment found that the maximum weight ratio (MR) rule and the maximum weight (MW) rule are the ideal dispatching solutions to the multiple AYCs dispatching problem.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.38 no.3
• /
• pp.78-86
• /
• 2015

Up-to-date business environment for manufacturers is very complex and rapidly changing. In other words, companies are facing a variety of changes, such as diversifying customer requirements, shortening product life cycles, and switching to small quantity batch production. In this situation, the companies are introducing the concept of JIT (just-in-time) to solve the problem of on-time production and on-time delivery for survival. Though many companies have introduced ERP (enterprise resource planning) systems and MRP (material requirement planning) systems, the performance of these systems seems to fall short of expectations. In this paper, the case study on introducing an APS (advanced planning and scheduling) system based on dispatching rules to a machining company and on finding a method to establish an efficient production schedule is presented. The case company has trouble creating an effective production plan and schedule, even though it is equipped with an MRP-based ERP system. The APS system is applied to CNC (computer numerical control) machines, which are key machines of the case company. The overall progress of this research is as follows. First, we collect and analyze the master data on individual products and processes of the case company in order to build a production scheduling model. Second, we perform a pre-allocation simulation based on dispatching rules in order to calculate the priority of each order. Third, we perform a set of production simulations applying the priority value in order to evaluate production lead time and tardiness of pre-defined dispatching rules. Finally, we select the optimal dispatching rule suitable for work situation of the case company. As a result, an improved production schedule leads to an increase in production and reduced production lead time.

• Journal of the Korea Society for Simulation
• /
• v.8 no.4
• /
• pp.73-87
• /
• 1999

Order Review/Release (ORR) System is the linkage between planning system and actual production. Reduction of the waiting time on the machines, work in process and lead time variation may be achieved by adopting ORR strategies. But researchers on the ORR do not agree on the effectiveness of ORR. Some say that the overall system flow time may be increased if ORR is adopted, but others say that ORR can reduce work in process, flow time and variation of flow time. The objective of this research is to clarify under what environments order release strategy is effective. Simulation study was conducted in a hypothetical job shop. The experimental results show that dispatching rule is much more important than ORR is in controlling the shop floor. But the results indicate that ORR can reduce mean shop flow time, average work in process and variation of shop flow time under such environments where utilization level is high and planned order is weekly released to the order pool. And the results also show that the effect of plan smoothing on the ORR is insignificant, which is inconsistent with the results of the previous researches.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.2
• /
• pp.315-324
• /
• 2016

The purpose of this study was to present the future directions for strengthening the TLO(Technology licensing office)s' expertise of universities by examining the impact on utilizing the university management experts for patents and technology transfer. To identify the specific effects of dispatching patent management experts, this study was conducted under various conditions, such as the dispatch status, the dispatching duration of patent management experts and the starting year of dispatching them. The data were analyzed by utilizing the data of the KIPSI's supporting program of dispatching the patent management expert to universities and the data of University Information Disclosure site. The data from a total of 110 four-year universities from 2008 to 2013 were used. According to the analysis result, the technology transfer's performance and technology transfer's income of universities of utilizing the patent management experts compared to universities not utilizing them appeared to be high. Technology transfer and technology transfer income appeared to be higher with a longer period of utilizing the patent management expert at university. This suggests that the direction is required to provide the plan for a longer period to maximize the effect of the program "The dispatching a patent management expert". The technology transfer's performance and technology transfer's income did not increase according to the year of dispatched the patent management expert at the university. A comparison of before and after dispatching, the technology transfer performance appeared to be high after dispatch. This suggests that the effects of dispatching the patent management experts at a university can be interpreted as a subsequent effect, rather than an immediate effect. Therefore, it does not simply limit the effectiveness of the dispatch business in the short term, but it needs to activate the technology transfer organization, such as a patent management expert in the long term.

• Journal of the Korea Society for Simulation
• /
• v.27 no.2
• /
• pp.71-81
• /
• 2018

Forklifts in a shipyard lift and transport heavy objects. Tasks occur dynamically and the rate of the task occurrence changes over time. Especially, the rate of the task occurrence is high immediately after morning and afternoon business hours. The weight of objects varies according to task characteristic, and a forklift also has the workable or allowable weight limit. In this study, we propose an online forklift dispatching algorithm based on nearest-neighbor dispatching rule using minimal cost assignment approach in order to attain the efficient operations. The proposed algorithm considers various types of forklift and multiple jobs at the same time to determine the dispatch plan. We generate dummy forklifts and dummy tasks to handle unbalance in the numbers of forklifts and tasks by taking their capacity limits and weights. In addition, a method of systematic forklift selection is also devised considering the condition of the forklift. The performance indicator is the total travel distance and the average task waiting time. We validate our approach against the priority rule-based method of the previous study by discrete-event simulation.

• The Journal of Information Systems
• /
• v.17 no.4
• /
• pp.301-319
• /
• 2008

The display market has been replaced by the FPD (Flat Panel Display) from the CRT (Cathode-Ray Tube) since the late 1990s. In the FPD production line, the most equipment has high price. Thus, when the equipment has multi-function, the repetitive process is arranged for the equipment. However, such disposition of equipment results in more complicated process flow owing to repetitive operations. This reduces the production capacity and increases lead-time in turn. In this paper, we develop an AutoMod simulation system that derives to information about the quantity, production lead-time, utilities of facilities, and occupation rates of racks. In this simulation system, we consider the situation where the equipment might be broken and suspended randomly. For the developed system, we first evaluate a production plan with current layout and then, propose a revised alternative plan. Using the same simulation scheme, we investigate comparing the production quantity and lead-time with the two plans. In addition, for a proposed alternative, we try to forecast the most adequate rule between the two job dispatching rules which are FOR (Fewest Operation Remaining) and FCFS (First Come First Serve) through simulation.

• Journal of the Korean Society for Precision Engineering
• /
• v.14 no.10
• /
• pp.75-84
• /
• 1997

This paper describes the development of an integrating method for process planning and scheduling activities for block assembly in shipbuilding. A block is composed of several steel plates and steel sections with the predetermined shapes according to the ship design. The parts which constitute the block are manufac- tured by cutting and/or bending operations, which are termed as machining operation in this paper. The machining operation is the first process for block assembly which influences the remaining block assembly processes. Thus process planning and scheduling for machining operation to manufacture parts for block are very important to meet the assembly schedule in the shipyard. An integrating method for process plan- ning and scheduling is developed by introducing the concept of distributed process planning and scheduling composed of initial planning, alternative planning and final planning stages. In initial planning stage, nesting parts information and machining emthods are generated for each steel plate. In alternative plan- ning stage, machine groups are selected and workcenter dispatching information is generated. In final planning stage, cutting sequences are determined. The integrated system is tested by case study. The result shows that the integrated system is more efficient than existing manual planning system.

• Journal of Navigation and Port Research
• /
• v.45 no.6
• /
• pp.314-324
• /
• 2021

Competition between ports around the world is intensifying to attract transshipment cargo. However, recently, there have been concerns about the departure of transshipment cargo volume at Busan Port, such as the lifting of the cabotage policy in China's shipping sector and the implementation of a safe fare system. In terms of operation, terminal congestion and vehicle waiting time are seriously occurring due to imbalance in the transshipment volume of each terminal and vehicles concentrated in a specific time period. In this paper, we propose a method of inter-terminal transportation (ITT) using buffer space to solve the problem caused by inefficient ITT systems and presented a mixed integer programming (MIP) for the problem. The effect of using the buffer space was analyzed for various work volumes and capacity fluctuation ranges by applying the terminal congestion pattern and ITT vehicle in/out pattern based on the Busan New Port data.

• Journal of Arbitration Studies
• /
• v.15 no.3
• /
• pp.139-174
• /
• 2005

Since a declaration between North and South Korea was adopted, North and South Korea has strengthened the interchange and cooperation between each other in many fields. Especially, the interchange and cooperation in the field of industrial property right, such as patent and trademark, are required to keep up with the age of the knowledge industry. But, until a recent date, there has been little interchange or cooperation in the field of industrial property right, and a few major companies were attempt to apply for the patent in North Korea through the Third country The system of industrial property laws in North and South Korea are very different because of time and political ideology barriers. To unify the system of industrial property laws in North and South Korea, firstly, North and South Korea must try to recognize and understand the dissimilarity between them. In this article, I compared the system of industrial property law of South Korea with that of North Korea to search commonalities and dissimilarities. Furthermore, it is needed to establish systematic devices for understanding of between North and South Korea, for instance, conducting a interdisciplinary seminar or dispatching a judge mutually. Finally, it is necessary to phase in a practical plan for unification. In the short run, mutual application and registration have to be authorized, and in the long view, unifying the practice of industrial property law service is needed. At the conclusion, the industrial property laws in North and South Korea can be unified systematically. In other words , to unify system of industrial property laws in North and South Korea, it is prerequisite that mutual understanding of industrial property laws and performance of the unify plan. The interchange and cooperation in this field will not only promote technical development but also create common interests of North and South Korea by expanding an opportunity for creating and utilizing industrial property.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.28 no.1
• /
• pp.1-10
• /
• 2003

A recent trend In flexible manufacturing systems (FMS) Is to utilize the Identical versatile machines with fast tool delivery devices. Unlike a conventional FMS where parts are fed to the machines with the required tools, tools are acquired from other machines using a tool delivery system and parts can be finished on the same machine In these FMS. Therefore it Is more important problem 4o plan tool flow using tool delivery system In these FMS rather than part flow In conventional FMS. According to the existing study, In FMS 20∼30 percent of the total management cost Is the cost related with tools and It Is possible to reduce the tool Inventory by 40 percent using efficient tool allocation. In this study, In FMS under dynamic tool allocation strategy, a new method of part release considering tool flow at the stage of part release Is proposed. In order to prove the efficiency of the proposed part release It is compared with other part release through simulation experiments. Performance measures in these experiments are the throughput and the number of tardy parts.