• 대한산업공학회지
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• 제29권1호
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• pp.65-77
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• 2003

This paper addresses FMS(Flexible Manufacturing System) loading problems with machine, tool and process flexibilities. When designing FMS planning, it is important to take account of these flexibilities for an efficient utilization of the resources. However, almost all the existing researches do not appropriately consider various flexibilities due to the problem complexity. This paper presents a new evolutionary algorithm to solve the FMS loading problems with machine, tool and process flexibilities. The algorithm is named a multi-level symbiotic evolutionary algorithm. The proposed algorithm is compared with the existing ones in terms of solution quality and convergence speed. The experimental results confirm the effectiveness of our approach.

• Industrial Engineering and Management Systems
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• 제11권3호
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• pp.215-223
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• 2012

This paper focuses on three very similar evolutionary algorithms: genetic algorithm (GA), particle swarm optimization (PSO), and differential evolution (DE). While GA is more suitable for discrete optimization, PSO and DE are more natural for continuous optimization. The paper first gives a brief introduction to the three EA techniques to highlight the common computational procedures. The general observations on the similarities and differences among the three algorithms based on computational steps are discussed, contrasting the basic performances of algorithms. Summary of relevant literatures is given on job shop, flexible job shop, vehicle routing, location-allocation, and multimode resource constrained project scheduling problems.

• 지능정보연구
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• 제2권2호
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• pp.69-83
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• 1996

The objective of this research is to develop a knowledge acquisition and refinement method for a multi-objective and multi-decision FMS scheduling problem. A competitive neural network and an inductive learning algorithm are integrated to extract and refine necessary scheduling knowledge from simulation outputs. The obtained scheduling knowledge can assist the FMS operator in real-time to decide multiple decisions simultaneously, while maximally meeting multiple objective desired by the FMS operator. The acquired scheduling knowledge for an FMS scheduling problem is tested by comparing the desired and the simulated values of the multiple objectives. The result show that the knowledge acquisition and refinement method is effective for the multi-objective and multi-decision FMS scheduling problems.

• 디지털산업정보학회논문지
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• 제8권3호
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• pp.87-95
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• 2012

Up to now, industrial cranes play important roles as the effective machines to carry heavy loads in the manufacturing premise, in the construction field and so on. And, a crane is widely used not only to daily work but also to carry heavy materials efficiently in a construction site for prevention of accident. However, the crane operation is highly complicated even for experts. In this paper, we developed the content of the crane mounted on the controller. This content overload conditions in the operating environment for the crane operator to warn, and the operation of equipment has the capability to limit automatically. The content for crane controller is to alert the operator overload and to limit the operation of equipment for stabilizing capabilities. The content of the flexible algorithm is based on stabilizing controllers, PLC (Programmable Logic Controller) to connect for using the equipment and electrical control systems to ensure the safety of workers and to improve the ability to work possible.

• 공업화학
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• 제34권3호
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• pp.226-240
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• 2023

This paper provides an overview of the trends and future directions in the development of anode materials for solid oxide fuel cells (SOFCs) using hydrocarbons as fuel, with the aim of enabling a decentralized energy supply. Hydrocarbons (such as natural gas and biogas) offer promising alternatives to traditional energy sources, as their use in SOFCs can help meet the growing demands for energy. We cover several types of materials, including perovskite structures, high-entropy alloys, proton-conducting ceramic materials, anode on-cell catalyst reforming layers, and anode functional layers. In addition, we review the performance and long-term stability of cells based on these anode materials and assess their potential for commercial manufacturing processes. Finally, we present a model for enhancing the applicability of fuel cell-based power generation systems to assist in the realization of the H₂ economy as the best practice for enabling distributed energy. Overall, this study highlights the potential of SOFCs to make significant progress toward a sustainable and efficient energy future.

• 한국정밀공학회지
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• 제34권3호
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• pp.167-172
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• 2017

This study proposes a method for identifying correlations between tension and drop height for sessile droplets in a roll-to-roll processing system. The effect of tension and drop height on the contact angle of a sessile droplet is presented. Design of experiment (DOE) methodology and statistical analysis are used to define a correlation between the process parameters. The contact angle is decreased while increasing tension and drop height. The influence of the tension is less significant on the contact angle compared with the effect of the drop height. However, tension should be considered as a major parameter because it is not easy to fix with roll eccentricity and compensating speed of the driven roll. The results of this study show that the effect of tension on the contact angle of a sessile droplet is more important than drop height because the drop height is fixed when the process systems are determined.

• 한국정밀공학회지
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• 제22권9호
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• pp.107-114
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• 2005

With the recent progress in flexible manufacturing systems (FMS) in industry, increasing attention has been given to Automatic Guided Vehicle (AGV) systems. An AGV is a self-powered unit for transporting materials between stations without needing to be controlled by an operator. Such a system has several sensors to recognize the external state, and it is designed to travel between stations automatically without external assistance. To manage each device automatically in real time it requires a distributed controller with a main computer as the host, as well as a number of micro-controllers. In this study, an AGV system with dual motor drive was constructed. A Pentium 4 personal computer was set up as the main host for the distributed control, and this communicated with other micro-controllers in the management of the motor. The speed of each motor was also controlled by a micro-controller.

• 한국정밀공학회지
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• 제33권2호
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• pp.115-119
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• 2016

Winding is one of the major processes in roll-to-roll systems. Taper tension profile in a winding determines the distribution of stress in the radial direction, i.e., the radial stress in the wound rolls. Maximum radial stress is major cause of material defect, and this study has been actively proceeded. Traditional models of radial stress model were focused on flexible and light substrate. In this study, we developed an advanced radial stress model including effects of both these parameters(weight and stiffness) on the radial stress. The accuracy of the developed model was verified through FEM(Finite Element Method) analysis. FEM result of maximum radial stress value corresponds to 99 % in comparison to result with the model. From this study, the material defects does not occur when the steel winding. And steel industry can be applied to improve the winding process.

• 제어로봇시스템학회논문지
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• 제15권11호
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• pp.1122-1129
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• 2009

Recently taping robot with smart recognition function have been studied in the coil manufacturing field. Due to the difficulty of 3D surface processing from the complicated working environment, it is not easy to accomplish smart tape attachment motion with non-contact sensor. To solve these problems the applicable surface recognition algorithm and a flexible sensing device has been recommended. In this research, the fusion method between 1D displacement and 3D laser scanner is applied for robust tape attachment about cold rolled coil. With these sensors we develop a two-step exploration and the smart algorithm for the awareness of non-aligned coil's information. In the proposed robot system for tape attachment, the problem is reduced to coil's radius searching with laser displacement sensor at first, and then position and orientation detection with 3D laser scanner. To get the movement at the robot's base frame, the hand-eye compensation between robot's end effector and sensing device should be also carried out respectively. In this paper, we examine the auto-coordinate transformation method in the calibration step for the real environment usage. From the experimental results, it was shown that the taping motion of robot had a robust under the non-aligned cold rolled coil.

• 대한조선학회논문집
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• 제54권5호
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• pp.415-420
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• 2017

Insulation systems in Liquefied Natural Gas Carriers (LNGC) are vulnerable to sloshing impact and fatigue loads because of waves. If gas leaks into the primary barrier, the Flexible Secondary Barrier (FSB) prevents the leakage of gas in this system. Fatigue strength of the FSB largely depends on the behavior of composite materials. In this study, a new system is applied to the FSB using aramid fiber to improve the fatigue strength of the secondary barrier, with the intention of replacing conventional E-glass fibers. The manufacturing method involved varying the ratio of the aramid fiber to the E-glass fiber for optimum design of the FSB. The fatigue tests results of the secondary barrier using aramid fiber were superior to that using E-glass fiber. The statistical analysis is performed to obtain the fatigue test results and estimate the probability of failure as well as the design guideline of LNGC secondary barriers.