• 대한산업공학회지
• /
• 제42권6호
• /
• pp.404-411
• /
• 2016

In footwear manufacturing systems, the upper parts of the shoes are manually sewed on a sub-line while bottom parts are produced by machines such as injection and molding machines on a sub-line before these two parts are combined into complete shoes on a final assembly line. The manual operations for the upper parts lead to a large variability in processing times, resulting in higher work-in-process inventory. In most footwear industries, production lines have been controlled by MRP-based push systems. Some industries attempt to introduce Kanban-based pull systems. This paper identifies the characteristics of the footwear manufacturing processes, and discusses the problems of the current control systems. As an operational alternative, a CONWIP-based control strategy is presented. Simulation experiments are performed to examine the performance of the control strategies.

• 한국토양비료학회지
• /
• 제42권Spc호
• /
• pp.8-13
• /
• 2009

심층토 내에서의 흐름과 이동과정을 포함하는 연구와 관리 측면에서 수학모델에 대한 관심도가 점점 증가하고 있다. 로제타는 토성이나 용적밀도 자료와 같은 대체 토양자료로부터 불포화수리특성에 대한 자료를 추정하는 프로그램이다. 이와 같은 형태의 모델은 애초 기본 토양자료를 수리특성자료로 전환하기 시작한 이래 대체 측정수단으로서 PTF라 불리워졌다. 이러한 기능은 유사-실험모델을 사용하여 예측한 자료를 근간으로 하여 직간접적으로 토양수분을 추정할 수 있다.

• Asia pacific journal of information systems
• /
• 제21권2호
• /
• pp.43-58
• /
• 2011

Support vector machines (SVMs), a machine learning technique, has been applied to not only binary classification problems such as bankruptcy prediction but also multi-class problems such as corporate credit ratings. However, in general, the performance of SVMs can be easily worse than the best alternative model to SVMs according to the selection of predictors, even though SVMs has the distinguishing feature of successfully classifying and predicting in a lot of dichotomous or multi-class problems. For overcoming the weakness of SVMs, this study has proposed an approach for selecting features for multi-class SVMs that utilize the impurity measures of classification trees. For the selection of the input features, we employed the C4.5 and CART algorithms, including the stepwise method of discriminant analysis, which is a well-known method for selecting features. We have built a multi-class SVMs model for credit rating using the above method and presented experimental results with data regarding S&P 500 companies.

• 산업기술연구
• /
• 제18권
• /
• pp.139-148
• /
• 1998

Traditionally, the problems of manufacturing technology and manufacturing management have been treated independently. In this research, we endeavor to integrate the process planning and scheduling activities as an attempt to integrate the two realms. To draw up a plan of process planning and scheduling in real manufacturing environment is not an easy task because available time to plan could be limited and the shop status could change frequently. So we propose an architecture of integrated process planing and scheduling problem within the allowed time even if sheep situations change rather frequently. We argue that we can obtain a better and practical scheduling solution by dynamically changing the processing machines and operations as the shop condition changes. The proposed system takes the initial information for alternative machines and operations represented by an AND/OR graph as its input. Other informational inputs to the system are part order and shop statues. The system then generates new process plan and schedules during permitted time. Experimental results show that the proposed scheme provides a viable solution for real world scheduling problems.

• Journal of international Conference on Electrical Machines and Systems
• /
• 제1권1호
• /
• pp.61-66
• /
• 2012

Linear motors has been developed for factory automation, transportation applications, among other applications. As the trend toward compact sizes in micro electronic products progresses, the required motor drives in these applications need to be downsized with increased power densities. It appears that the winding of miniature linear motors is the most awkward part to be scaled down from conventional motor designs when miniaturizing. This paper presents an alternative design for slotless linear motors. A novel flexible printed circuit winding has been applied to obtain a simplified but qualified result. Having explained the prototyping and inspection, a discussion is given to examine the achievement of this study.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.109.2-109
• /
• 2001

In the PCB assembly lines, as components become more complex and smaller, the conventional inspection method using traditional ICT and function test show their limitations in application. The automatic optical inspection(AOI) gradually becomes the alternative in the PCB assembly line. In Particular, the PCB inspection machines need more reliable and flexible object recognition algorithms for high inspection accuracy. The conventional AOI machines use the algorithmic approaches such as template matching, Fourier analysis, edge analysis, geometric feature recognition or optical character recognition (OCR), which mostly require much of teaching time and expertise of human operators. To solve this problem, in this paper, a statistical learning based part recognition method is proposed. The performance of the ...

• 한국경영과학회지
• /
• 제30권3호
• /
• pp.55-65
• /
• 2005

In recent manufacturing systems, most jobs may have several process plans, such as alternative sequence of operations, alternative machine etc. A few researches have addressed the necessity for the integration of process planning and scheduling function for efficient use of manufacturing resources. But the integration problem is very difficult and complex. Many prior researches considered them separately or sequentially. It introduces overlapping or partial duplications in solution efforts. In this paper, Integration problem of jobs with multiple process plans in a job shop environment Is addressed. In order to achieve an efficient integration between process planning and scheduling by taking advantage of the flexibility that alternative process plans offer, we designed GA(Genetic Algorithm)-based scheduling method. The performance of proposed GA is evaluated through comparing integrated scheduling with separated scheduling in real world company with alternative machines and sequences of operations. Also, a couple of benchmark problems are used to evaluate performance. The integrated scheduling method in this research can be effectively epplied to the real case.

• 대한치과의사협회지
• /
• 제50권4호
• /
• pp.180-188
• /
• 2012

Cone beam computed tomography(CBCT) machines recently developed in Korea, being designed for imaging hard tissues of the oral and maxillofacial region. I reported a brief overview of CBCT system, in comparison with coventional computed tomography(CT) system. CBCT provides high resolution, simpler image acquisition, lower dose and cost alternative to conventional CT, promising to revolutionize the practice of oral and maxillofacial radiology.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1995년도 추계학술대회 논문집
• /
• pp.859-863
• /
• 1995

Presented in the paper are a review of sorting and buffering system(SBS), the design procedure of a SBS and an analytical model for the initial alternative generation. SBS is an automated material handling system in which incoming items of different part types are automatically sorted and buffered so that the processing machines can process the part in lots. SBSs play a key role in modern manufacturing systems ans are widely found in mass fabrication lines, packaging and palletizing, and disribution centers.

• 경영과학
• /
• 제13권2호
• /
• pp.147-161
• /
• 1996

Due-date is an important factor in Flexible Manufacturing System scheduling. Even though most of researchers have focused part selection and loading problem using fixed due-date assignment rules, FMSs consist of multi-function machines which facilitate alternative processes. This research investigates interactions of three dispatching mechanisms, three NSS (Next Station Selection) rules and four due-date assignment rules using simulation. Both cost-based and time-based performance measures are considered in this research.