• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.1642-1649
• /
• 2010

At present, KORAIL is in the middle of renovating. All steps exert great effort at cost reduction and a profit improvement. Especially to improve maintenance method and inspection period at the rolling-stock division lots of research is under progress. Daily inspection of rolling stocks is to operate the rolling stock normally. Daily inspection items are driving control device, coupling device, brake system, water system and air conditioning system, electrical system etc. Half of the maintenance manpower are inputted at daily inspection. Strengthens the quality and optimize the proportion of daily inspection are urgent problem. Daily inspection period extension aim is as follows. KTX from 3,500km to 5,000km, passenger car from 1st to 3,500km, new style electric locomotive from 2nd to 5,000km, the diesel locomotive is 2,800km from 1,200km. In this paper, the optimal daily inspection period and methods are considered including expected problem and counter measures.

• Management Science and Financial Engineering
• /
• v.15 no.2
• /
• pp.53-68
• /
• 2009

In this paper, we address a problem for minimizing the number of items inspected in a back-light-unit (BLU) inspection system, which includes a K-stage inspection system, a source inspection shop, and a re-inspection shop. In order to formulate our objective, we make a steady-state flow analysis between nodes (or shops), and derive the steady-state amount of flows between nodes and defective rates by solving a nonlinear balance equation. We provide an enumeration method for determining an optimal value of K which minimizes the number of items inspected. Our methodology could be applied and extended to similar situations with slight modification.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1998.03a
• /
• pp.82-87
• /
• 1998

Laser printer, faximile and copy machine are a few examples of OA(office automation) system. In such a system, the reflecting mirror has been employed for transmitting a target image to optical device. Therefore, to develope a good quality of optical system, the quality control of optical mirror was required. In recent years, considerable efforts have been directed toward the development of automated optical glass inspection system because the inspection is eye-fatigue and monotonous job for humans to perform. In this paper, we propose a inspection system applying algorithm of image processing for detecting defects of optical glass such as pinhole, scratch. From the experiments, the proposed inspection system shows reliable results.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.05a
• /
• pp.396-399
• /
• 2004

This study was performed to develop necessary Visual Inspection System for the PSC Bridges precision safety diagnosis which to enhance the efficiency and accuracy of visual inspection by using mobile PC and adopted IT. This system was constructed to the automatic visual inspection map generating program and the Visual Inspection System using mobile PC that predicted high efficiency.

• Journal of the Korean Data and Information Science Society
• /
• v.16 no.4
• /
• pp.725-733
• /
• 2005

A system subject to random shocks is considered. The shocks arrive according to a Poisson process and the amount of each shock is exponentially distributed. In this paper, a periodic inspection policy for the system is compared with a random inspection policy. After assigning several maintenance costs to the system, we calculate and compare the long-run average costs per unit time under two policies.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2000.10a
• /
• pp.51-56
• /
• 2000

This study is to implement automatic inspection system of motor body panel by visual system. since it is inefficient to examine adhesion condition of components with the naked eye, image processing algorithm is presented to replace the existing manual inspection process with an automatic inspection process the developed automatic inspection system presents tile examination method of the adhesion condition of components with a pixed camera, which leads to an increase of the productivity and a reduction of manufacturing cost

• Journal of Institute of Control, Robotics and Systems
• /
• v.13 no.11
• /
• pp.1106-1111
• /
• 2007

The visual inspection method that depends on human's eyes has some problem that a lot of variations happen in examination according to bodily, spiritual state of the checker. We automate remocon inspection process using CCD camera. Our developed inspection system can be used in any remocon production line without the user's big handling. Our inspection system was developed using PC, CCD Camera, Visual C++ for universal work place. The accuracy of proposed system was improved about 3.2[%] than the conventional pattern matching method and the processing time was decreased about 119[ms]. Also we showed that our inspection system is more robust to lighting circumstances.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.13 no.3
• /
• pp.37-43
• /
• 2004

The purpose of this study is to develop a practical image inspection system that could recognize it correctly, endowing flexibility to the productive field, although the same object for work will be changed in the size and rotated. In this experiment, it selected a fighter, rotating the direction from $30^{\circ}$ to $45^{\circ}$ simultaneously while changing the size from 1/4 to 1/16, as an object inspection without using another hardware for exclusive image processing. The invariant moments, Hu has suggested, was used as feature vector moment descriptor. As a result of the experiment, the image inspection system developed from this research was operated in real-time regardless of the chance of size and rotation for the object inspection, and it maintained the correspondent rates steadily above from 94% to 96%. Accordingly, it is considered as the flexibility can be considerably endowed to the factory automation when the image inspection system developed from this research is applied to the productive field.

• Journal of Korean Institute of Industrial Engineers
• /
• v.17 no.1
• /
• pp.17-27
• /
• 1991

Whenever environment allows for a more efficient application of the advanced methods published in books or articles, such methods must necessarily be applied in practice. One of the major reasons why the numerous methods are ignored is the lack of experts who could make selections of proper inspection method. An expert system which would perform as if each factory had a resident expert is developed. The expert system is mainly comprised of three parts. The first part presents the performance measures of the inspection methods currently used or inquired. The system includes almost all the inspection methods presented in Schilling's book. The second part presents an appropriate inspection method by inputting various environments through the user interface. The third part prints the inspection methods in accordance with the format which will be used in the field, stores the inspection results that follow, and then administers the acceptance inspection as a system by considering the past results.

• Management Science and Financial Engineering
• /
• v.13 no.2
• /
• pp.141-157
• /
• 2007

In this paper, we address a design problem and a case study of a K-stage back-light-unit(BLU) inspection system, which is composed of K stages, each of which includes an inspection process and a rework process. Assuming the type I, II errors and the inspection-free policy for items classified as good, we determine the smallest integer of K which can achieve a given target defective rate. If K does not exist, holding the current values of the type I, II errors, we search reversely the defective rate of an assembly line and the defective rate of a rework process, to meet the target defective rate. Our formulae and methodology based on a K-stage inspection system could be applied and extended to similar situations with slight modification.