• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.393-396
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• 2005

Due to the fast growing rate of the global container trade, every major port is under the pressure of meeting the projected capacity demand. As a result, alternative solutions have been sought for improving capacity and meeting the growing demand for container storage area and terminal capacity. Moreover, material handling process re-engineering is now a critical issue for logistics and supply chain managers of airline, shipping lines, terminal and warehousing enterprises around the world. Therefore, the purpose of this paper is to develop the 3D simulator for executing performance valuation of port transportation systems. The developed 3D simulator system is to measure the effectiveness of the proposed total system and compare it with existing practices. The performance analysis variables are also defined for these comparisons

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.2
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• pp.139-155
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• 2003

The aim of this study is to identify the data traffic capacity of 3G mobile communication networks, especially of cdma2000-1X networks. Three-layered ON/OFF traffic model is used to describe the dynamics of data traffics and the process of data transmission such as packet scheduling. We construct a simulator fully incorporating packet handling process of cdma2000-lX data network as well as three-layered ON/OFF traffic model describing the behavior of source data traffics. To get influence of traffic parameters on performance measures, the extensive simulations were performed for several data sets which are obtained from real trace data or previous studies. The experimental results show that the engineered throughput satisfying QoS criteria is approximately 25% of total capacity. Finally, some proposals to improve the system capacity are followed.

• Journal of the Korean Operations Research and Management Science Society
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• v.26 no.1
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• pp.71-85
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• 2001

This paper considers a cost model for a U-shaped manufacturing cell formation which incorporates a required number of machines and various material flows together under multi-part multi-cell environment. The model is required to satisfy both the specified operation sequence of each part and the total part demand volume, which are considered to derive material handling cost in U-shaped flow line cells. In the model several cost-incurring factors including set-up for batch change-over, processing time for operations of each part, and machine failures are also considered in association with processing load and capacity of each cell. Moreover, a heuristic for a good machine layout in each cell is newly proposed based on the material handling cost of each alternative sequence layout. These all are put together to present an efficient heuristic for the U-shaped independent-cell formation problem, numerical problems are solved to illustrate the algorithm.

• The Journal of Korea Robotics Society
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• v.11 no.4
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• pp.242-247
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• 2016

A robot manipulator handling a heavy weight requires high-capacity motors and speed reducers, which increases the cost of a robot and the risk of injury when a human worker is in collaboration with a robot. To cope with this problem, we propose a collaborative manipulator equipped with a counterbalance mechanism which compensates mechanically for a gravitational torque due to the robot mass. The prototype of the manipulator was designed on the basis of a four-bar linkage structure which contains active and passive pitch joints. Experimental performance evaluation shows that the proposed robot works effectively as a collaborative robot.

• IE interfaces
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• v.16 no.spc
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• pp.93-98
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• 2003

This paper addresses an AGV dispatching problem in semiconductor clean-room bays where AGVs move cassettes of wafers between machines or machines and a central buffer. Since each machine in a bay has a local buffer of limited capacity, material flow should be controlled in a careful way to maintain high system performance. It is regarded that two most important performance measures in a semiconductor bay are throughput rate and lead-time. The throughput rate is determined by a bottleneck resource and the lead-time depends on smooth material flow in the system. This paper presents an AGV dispatching procedure based on the concept of theory of constraints (TOC), by which dispatching decisions are made to utilize the bottleneck resource at the maximum level and to smooth the flow of material. The new dispatching procedure is compared with existing dispatching rules through simulation experiments.

• KSBB Journal
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• v.9 no.2
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• pp.98-103
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• 1994

A bed configuration wherein sheets of modified fibrous polyethylene are potted within a Millipore Filter Cartridge matrix has been developed. Polyethylene fibers form sturdy beds but the native hydrophobicity and inertness of polyethylene have precluded their use in protein chromatography The polyethylene fibers used in this system were modified by plasma oxidation and further derivatization. The resulting fibers are hydrophilic, bind protein reversibly and serve as an anion-exchange stationary phase. Separation of Bovine Serum Albumin on this bed, as well as results of basic studies on capacity and reversibility of binding within a fibrous bed and experimental data handling system are shown.

• Journal of Korea Port Economic Association
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• v.19 no.1
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• pp.43-68
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• 2003

With development of Asia's economy, the ports in trunk route have increased its handling capacity According to previous studies, main determinants to become hub-port are referred to location, connection inland transport with hinterland, port service availability and efficiency, cost of port handling, socio-economic stability and port information system etc. This study aims to investigate the changes in factors determine port's competitiveness particularly in Asian neighbor ports such as Hong Kong port and Shenzen port, and Singapore port and the Port of Tanjung Pelapas in Malaysia by comparing and analyzing main indicators relating to those ports. In conclusion, main reasons which gained competitiveness by newly developed ports such as Shenzen port and the Port of Tanjung Pelapas were port price and massive hinterland space offered.

• Industrial Engineering and Management Systems
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• v.10 no.4
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• pp.255-263
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• 2011

During the design process of a terminal, the handling capacity of a container yard needs to be evaluated in advance. This study suggests formulas for estimating the expectations and the variances of cycle times for various types of operations of a yard crane. Statistical analysis is used to estimate the expectations and variances. The main focus of this study is to show the impact of interdependencies among handling time elements on the expectation and variance of the cycle times; these interdependencies have not been considered in previous studies. Numerical experiments are done for evaluating the difference in the variance of cycle times and the waiting of trucks between the cases with and without the consideration of interdependencies.

• Journal of Korean Institute of Industrial Engineers
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• v.18 no.2
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• pp.65-82
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• 1992

We present an approximate analytical model to estimate throughput capacity and expected waiting times for move requests of an Automated Guided Vehicle System(AGVS) used in manufacturing. This analytical model considers an empty vehicle dispatching rule, namely, the First-Come-First-Served(FCFS) rule. The performance of the analytical model is tested extensively through simulation. Using this model one can rapidly evaluate a wide range of handling and layout alternatives for given flow data. Hence, the model would be most effective when used early in the design phase to narrow down the set of alternative handling systems and configurations prior to simulation.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.1
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• pp.47-55
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• 2009

Sewers are important national infrastructure and play an essential part by handling both wastewater and stormwater to minimise problems caused to human life and the environment. However, they can cause urban flooding when rainfall exceeds the system capacity. Sewer flooding is an unwelcome and increasingly frequent problem in many urban areas, and its frequency will increase over time with urbanisation and climate change. Under current standards, sewers are designed to drain stormwater generated by up to 10 year return period storms, but data suggests that many in practice have been experienced flooding with exceeding system capacity under increased storm events. A large number of studies has considered upgrading or increasing the design standard but there are still lack of information to propose a suitable return period with the corresponding system quantity to achieve. A methodology is required to suggest a proper level of standard within a suitable sewerage rehabilitation planning that can avoid the exceedance problem. This study aimed to develop a methodology to support effective sewer rehabilitation that could prevent urban flooding mainly resulted from the exceedance of existing storm sewer system capacity. Selected sewerage rehabilitation methods were examined under different storm return periods and compared to achieve the best value for money.