• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.2
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• pp.111-120
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• 2017

This paper proposes an improved standard genetic algorithm (GA) of making a near optimal schedule for integrated process planning and scheduling problem (IPPS) considering tool flexibility and tool related constraints. Process planning involves the selection of operations and the allocation of resources. Scheduling, meanwhile, determines the sequence order in which operations are executed on each machine. Due to the high degree of complexity, traditionally, a sequential approach has been preferred, which determines process planning firstly and then performs scheduling independently based on the results. The two sub-problems, however, are complicatedly interrelated to each other, so the IPPS tend to solve the two problems simultaneously. Although many studies for IPPS have been conducted in the past, tool flexibility and capacity constraints are rarely considered. Various meta-heuristics, especially GA, have been applied for IPPS, but the performance is yet satisfactory. To improve solution quality against computation time in GA, we adopted three methods. First, we used a random circular queue during generation of an initial population. It can provide sufficient diversity of individuals at the beginning of GA. Second, we adopted an inferior selection to choose the parents for the crossover and mutation operations. It helps to maintain exploitation capability throughout the evolution process. Third, we employed a modification of the hybrid scheduling algorithm to decode the chromosome of the individual into a schedule, which can generate an active and non-delay schedule. The experimental results show that our proposed algorithm is superior to the current best evolutionary algorithms at most benchmark problems.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.9 s.186
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• pp.76-83
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• 2006

Machining accuracy is closely related with tool deflection induced by cutting forces. In this research, cutting forces and tool deflection in end milling are expressed as a closed form of tool rotational angle and cutting conditions. The discrete cutting fores caused by periodic tool entry and exit are represented as a continuous function using the Fourier series expansion. Tool deflection is predicted by direct integration of the distributed loads on cutting edges. Cutting conditions, tool geometry, run-outs and the stiffness of tool clamping part are considered together far cutting forces and tool deflection estimation. Compared with numerical methods, the presented method has advantages in prediction time reduction and the effects of feeding and run-outs on cutting forces and tool deflection can be analyzed quantitatively. This research can be effectively used in real time machining error estimation and cutting condition selection for error minimization since the form accuracy is easily predicted from tool deflection curve.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.8-13
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• 2001

In the turning process, the feed is usually selected by a machining operator considering workpiece, cutting tool and depth of cut. Even if this selection can avoid power saturation or tool breakage, it is usually conservative compared to the capacity of the machine tools and can reduce the productivity significantly. This paper proposes a selection method of the feed and the reference cutting force based on MRR(material removal rate), maximum spindle power and specific energy. In order to estimate and control cutting force accurately in transient and steady state, this study utilizes a synthesized cutting force estimation method and a Fuzzy controller. The experimental results present that these systems can be useful for the FMS(flexible manufacturing system) and unmanned automation system.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.183-188
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• 2002

Co-cured composite materials has its own characteristics, so its thermal expansion is different each other. The selection of tool material for co-cured composite part in high temperature more over $350^{circ}F$ and 50 Psi pressure have to consider part thermal expansion, size, shape, and economic aspect in production line. So it is important choose tooling material in manufacturing composite parts. We called the tool for airplane composite parts as BAJ (Bonding Assembly Jig). Composite parts are cured on the BAJ in autoclave. BAJ have to stable at high temperature over $350^{circ}F$ and 50 Psi pressure, Considering composite parts' dimensional tolerance compare to heat up in autoclave. This paper come from the results of the experiment at the composite parts production line and review other aircraft company's method for tooling This is for the engineer engaged in composite parts manufacturing.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.315-319
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• 1999

This paper has been considered on the cutting characteristics such as chip formation and surface roughness for Inconel 690 alloy with difficult-to-cut because of high toughness and strength. We have made efforts solving the problem to difficult-to-cut of Inconel by improvement of tool with TiN coating and the selection of optimum cutting condition. We used the CCD camera and the surface roughness tester to observe the chip formation and the state of machined surface by using the improved tool with diamond coating and various cutting condions. We have found that the chip formation showed the tooth shape of tooth blade and the surface roughness was very poor. but it can be better by selection of optimum cutting condition.

• Journal of Biomedical Engineering Research
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• v.26 no.6
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• pp.407-412
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• 2005

Convenience is one of the most important factors in medical image segmentation. Convenience is defined by compiling opinions from radiologists, and can be described as controllable maximum automation on the condition of producing only accurate results. The components of convenience are inclusive automation and inclusive modification. Inclusive modification consists of verify-and-confirm, undo-redo, exchange of segmentation methods, and intelligent modification tools. Inclusive automation is composed of automatic selection of a method, automatic selection of a confident segment, and automated chores. The convenient segmentation tool has been developed to segment X-ray images for orthopedic surgery, and has received an excellent evaluation from radiologists.

• Journal of the Korea Safety Management & Science
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• v.7 no.1
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• pp.57-76
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• 2005

A standardized ergonomics kit is suggested to evaluate and reduce musculoskeletal hazards that yield large socioeconomic burdens in the work system. This kit comprises basic and detailed analysis tools with proper tool selection rules. The basic tool includes a checklist for various risk factors to screen potentially hazardous jobs among manual works. Selective detailed analysis tools can then be applied to the screened job lists for more quantitative and precise evaluation. The tool selection rules are devised for using the basic and detailed analysis tools in a mutually supplemental way. To validate the standardized ergonomics kit, it was applied to evaluate jobs related to the musculoskeletal hazards in a paper-making industry. Among 101 manual jobs investigated, 44 potential hazardous jobs were screened during basic investigation phase and finally 16 hazardous jobs were identified by the detailed analysis phase. The result provided fairly promising ideas of ergonomic interventions for the hazardous jobs.

• Journal of the Korean Society of Safety
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• v.10 no.1
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• pp.9-19
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• 1995

The recent development of NC lathe and machining renter have enabled automatic or unmanned manufacturing system for the improvement of production rate. And if you want to introduce automatic or unmanned manufacturing system into the cutting process of cage motor rotor, the selections of effective cutting conditions, rational tool grades and tool angles are necessary. As a result, the selection of cutting conditions, tool grades and tool angles are important factors to production rate.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.11a
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• pp.208-212
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• 1999

In the use of glass fiber reinforced plastics(GFRP), cutting is often necessary. But the most of past studies have been interested in the effect of fiber orientation on tool wear. In this study, the effects of fiber contents on tool wear were investigated experimentally. By proper selection of cutting tool, the variables are cutting speed and fiber contents of 10, 20, 30wt% with fixed feed rate and depth of cut.

• Journal of the Korean Society of Safety
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• v.10 no.2
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• pp.46-55
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• 1995

The recent development of NC lathe and machining center have enabled automatic or unmanned manufacturing system for the improvement of production rate. And if you want to introduce automatic or unmanned manufacturing system into the cutting process of cage motor rotor, the selections of effective cutting conditions, rational tool grades and tool angles are necessary. As a result, the selection of cutting conditions, tool grades and tool angles are important factors to production rate.