• 한국정보전자통신기술학회논문지
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• 제5권1호
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• pp.13-19
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• 2012

본 논문에서는 계층적 삼차원 블록 영상분석을 이용한 폐결절 자동 검출 방법을 제안한다. 제안하는 블록 기반 폐 영상 분석 방법은 크게 두 부분으로 나눌 수 있다. 첫 번째는 블록을 분할하고 분석하고자 하는 대상 블록을 선택하는 과정이며 두 번째는 선택된 분석 대상 블록을 분석하는 과정이다. 첫 번째 과정을 통하여 선택된 분석대상 블록들은 다음 단계인 분석과정을 통해 결절과 비결절로 분리될 수 있다. 분석대상 블록의 중심에 있는 object에서 분석을 위한 형태 특징을 추출 하고, 추출된 형태 특징 값을 Support Vector Machine을 이용하여 결절과 비 결절로 분리한다.

• 동력기계공학회지
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• 제19권4호
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• pp.43-49
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• 2015

This study has been analyzed and investigated the possibility for the substitution of a heat source with the application of PTC(Positive Temperature Coefficient Heater) in a food drying machine. And this experiment was conducted to measure temperatures at the upper part of the vessel and the heat sink. And the structure has the many holes plane connected with the external air in the upper part of similar volumetric vessel, and attached to the PTC heater (3sets) of total consumption electricity of 120[W] in Al radiant heat structure and the small fan (2sets) in the suitable space of the lower part. Consequently, it was found that at the most conditions of food drying test with the seven holes(5mm) under the control temperature $62^{\circ}C$, the optimum drying condition formatted and the optimum time range especially appeared from 6,500 second to 7,000 second in case of drying test on banana sample.

• 조명전기설비학회논문지
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• 제23권2호
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• pp.62-69
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• 2009

본 논문에서는 전력용 변압기의 고장진단을 위해 써포트 백터머신에 기반을 둔 고장진단 알고리즘을 제안한다. 제안된 기법은 데이터 취득부, 정상/고장판별부, 고장원인판별부로 구성된다. 제안한 고장진단과정을 보면, 데이터 취득부에서는 변압기에서 가스성분을 취득한다. 정상/고장 판별부에서는 취득된 가스성분들을 KEPCO 규정과 비교하여 정상/고장 여부를 판단한다. 고장원인 판별부에서는 입력 데이터가 고장으로 판정이 난 경우에 다중-클래스 써포트 백터머신에 의해 고장원인을 판정한다. 제안된 방법은 사례연구를 통해 우수성을 입증하였다.

• Industrial Engineering and Management Systems
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• 제15권1호
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• pp.11-18
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• 2016

This paper considers a scheduling problem in a flexible job shop with a reconfigurable manufacturing cell. The flexible job shop has both operation and routing flexibilities, which can be represented in the form of a multiple process plan, i.e. each part can be processed through alternative operations, each of which can be processed on alternative machines. The scheduling problem has three decision variables: (a) selecting operation/machine pairs for each part; (b) sequencing of parts to be fed into the reconfigurable manufacturing cell; and (c) sequencing of the parts assigned to each machine. Due to the reconfigurable manufacturing cell's ability of adjusting the capacity, functionality and flexibility to the desired levels, the priority scheduling approach is proposed in which the three decisions are made at the same time by combining operation/machine selection rules, input sequencing rules and part sequencing rules. To show the performances of various rule combinations, simulation experiments were done on various instances generated randomly using the experiences of the manufacturing experts, and the results are reported for the objectives of minimizing makespan, mean flow time and mean tardiness, respectively.

• 한국정밀공학회지
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• 제34권3호
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• pp.173-178
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• 2017

Recently, a high-precision ball screw is an essential part of high-speed machines. However, producing high-precision ball screws has been costly and time-consuming. Nowadays, a whirling machine is used to produce high-precision ball screws efficiently. Rotating multi-tips are used to turn the ball screw in the whirling machine. In this study, a structural analysis was performed by a finite-element method to develop a whirling machine. An improved model of the whirling machine was proposed by the analysis. In addition, a thermal analysis was performed to confirm the thermal stability. The results of the analysis can be applied in order to further develop the whirling machine.

• 대한안전경영과학회지
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• 제9권5호
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• pp.79-85
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• 2007

Intelligent machines respond to external environments on the basis of decisions that are made by sensing the changes in the environment and analyzing the obtained information. This study focuses on the construction of a knowledge base which enables decision making with that information. Approximately 70% of all errors that occur in machine tools are caused by thermal error. In order to proactive deal with these errors, a system which measures the temperature of each part and predicts and compensates the displacement of each axis has been developed. The system was built in an open type controller to enable machine tools to measure temperature changes and compensate the displacement. The construction of a machining knowledge base is important for the implementation of intelligent machine tools, and is expected to be applicable to the network based intelligent machine tools which look set to appear sooner or later.

• 한국정밀공학회지
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• 제18권1호
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• pp.98-103
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• 2001

Machining is the commonly used process in the manufacturing of prototypes. This process offers several advantages, such as rigidity of the machine, precision of the machine, precision of the operation and specially a quick delivery. The weight and immobility of the machine support and immobilize the part during the operation. However, despite these advantages it shows, machining still presents several limitations. The immobilization, location and support of the part are referred to as fixturing or workholding and present the biggest challenge for time efficient machining. So it is important to select and design the appropriate fixturing assembly. This assembly depends on the complexity of the part and the tool paths and may require the construction of dedicated fixtures. With traditional techniques, the range of fixturable shapes is limited and the identification of suitable fixtures in a given setup involves complex reasoning. To solve this limitation and to apply the automation, this paper presents the Reference Free Part Encapsulation(RFPE) and implementation of the encapsulation system. The feature-based modeling system and the encapsulation system are implemented. The small part of which it is difficult to find out the appropriate fixturing assembly is made by this system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.711-712
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• 2012

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.1245-1246
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• 2013

• 대한산업공학회지
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• 제21권1호
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• pp.67-84
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• 1995

Five-axis NC machining is advanced machining technology by which highly geometrically complicated parts can be machined accurately with high machinability. In this paper, we investigate the problems of determining the machinability and part setup orientation for a given surface models. We first develop kinematic model of the five-axis machines based on the axis configuration, then develop algorithms for determining the feasibility of machining by one setup(machinability) and the part orientation for the C,A and A,B type configuration. The machinability is determined by computationally efficient procedure for finding the intersection between the feasible area on the sphere and the numerical map called binary spherical map(BSM), and the part setup is chosen such that the rotational range is minimized among the feasible configurations. The developed algorithms are tested by numerical simulations, convincing they can be readily implemented on the CAD/CAM system as an automated process planner giving the efficient machine type and setup for NC machining.