• International Journal of Reliability and Applications
• /
• v.5 no.1
• /
• pp.25-36
• /
• 2004

Ultrasonic inspection system consist of the examination procedures, equipment, and operators. The reliability of nondestructive testing is influenced by the inspection environment, materials and types of defect. It is very difficult to estimate the reliability of NDT due to the various factors. Piping inspection round robin was conducted to quantify the capability of ultrasonic inspection during in-service. In this study, the models for predicting the ultrasonic NDE reliability by logistic model and linear regression model are discussed. The utility of the NDT reliability assessment is verified by the analysis of the data from round robin test with these models.

• Journal of Korean Society for Quality Management
• /
• v.24 no.1
• /
• pp.20-31
• /
• 1996

A pure zero-one integer program is formulated for determining where to assign the inspection stations in a multi-stage production system. The objective fuction is formulated to minimize the overall inspection costs. One of the major characteristics of this system is that an assigned inspection station is to inspect only the items produced in previous manufacturing stages. Each inspection station can be assigned to any possible inspection stage between two manufacturing stages. Error-free and screening inspection policy is assumed in this system and the defective items found in any inspection station will be reworked at once. The integer programming model presented in this paper has the advantages in the ease of modeling and modifiing as compared with the existing dymanamic programming methods. The solutions of the model can be easily obtained by the commercially available softwares like LINDO and GAMS.

• Journal of Mechanical Science and Technology
• /
• v.20 no.4
• /
• pp.437-446
• /
• 2006

Laser vision inspection systems are becoming popular for automated inspection of manufactured components. The performance of such systems can be enhanced by improving accuracy of the hardware and robustness of the software used in the system. This paper presents a new approach for enhancing the capability of a laser vision system by applying hardware compensation and using efficient analysis software. A 3D geometrical model is developed to study and compensate for possible distortions in installation of gantry robot on which the vision system is mounted. Appropriate compensation is applied to the inspection data obtained from the laser vision system based on the parameters in 3D model. The present laser vision system is used for dimensional inspection of car chassis sub frame and lower arm assembly module. An algorithm based on simplex search techniques is used for analyzing the compensated inspection data. The details of 3D model, parameters used for compensation and the measurement data obtained from the system are presented in this paper. The details of search algorithm used for analyzing the measurement data and the results obtained are also presented in the paper. It is observed from the results that, by applying compensation and using appropriate algorithms for analyzing, the error in evaluation of the inspection data can be significantly minimized, thus reducing the risk of rejecting good parts.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2023.05a
• /
• pp.331-332
• /
• 2023

With the aging of buildings, the number and importance of regular inspections of buildings are increasing. The current safety inspection goes through a procedure in which a skilled technician visits an old building, visually checks it, takes a photo, and finally organizes and judges it at the office. For this, field personnel and analysis and review personnel are required. Since the inspection procedure includes taking pictures, a huge amount of data has been accumulated from the time digital photos were used to the present. When a model that can check cracks outside a building is developed using these data, manpower and time required can be greatly reduced. Therefore, this study aims to create a model for classifying cracks that occur outside the building through the artificial intelligence method. The created model can be used as a basic model for determining cracks only by external photography in the future, and furthermore, it can be used as basic data for calculating the size and width of cracks.

• Journal of Korean Society for Quality Management
• /
• v.51 no.4
• /
• pp.515-530
• /
• 2023

Purpose : This research aims to develop a data-driven inspection policy for radio stations utilizing the KS Q ISO 2859-1 sampling method, addressing potential regulatory relaxations and impending management challenges. Methods : Using radio station inspection big data from the past six years, we established a simulation model to evaluate the current policy. A new inspection sampling policy framework was designed based on the KS Q ISO 2859-1 method. The study compares the performance of the current and proposed inspection systems, offering insights for an improved inspection strategy. Results : This study introduced a simulation model for inspection system based on the KS Q ISO 2859-1 sampling method. Through various experimental designs, key performance indicators such as non-detection rate and sample proportion were derived, providing foundational data for the new inspection policy. Conclusion : Using big data from radio station inspections, we evaluated current inspection systems and quantitatively compared a new system across diverse scenarios. Our simulation model effectively verified the feasibility and efficiency of the proposed framework. For practical implementation, essential factors such as lot size, inspection cycle, and AQL standards need precise definition and consideration. Enhancing radio station inspections requires a policy-driven approach that factors in socio-economic impacts and solicits feedback from industry participants. Future study should also explore various perspectives related to legislative, institutional, and operational aspects of inspection organizations.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1996.03a
• /
• pp.24-29
• /
• 1996

The seniconductor, which is precision product, requires many inspection processes. The surface conditions of the semiconductor chip effect on the functions of the semiconductors. The defects of the chip surface is crack or void. Because general inspection method requires many inspection processes, the inspection system which searches immediately and preciselythe defects of the semiconductor chip surface. We propose the inspection method by using the computer vision system. This study presents an image processing algorithm for inspecting the surface defects(crack, void)of the semiconductor test samples. The proposed image processing algorithm aims to reduce inspection time, and to analyze those experienced operator. This paper regards the chip surface as random texture, and deals with the image modeling of randon texture image for searching the surface defects. For texture modeling, we consider the relation of a pixel and neighborhood pixels as noncasul model and extract the statistical characteristics from the radom texture field by using the 2D AR model(Aut oregressive). This paper regards on image as the output of linear system, and considers the fidelity or intelligibility criteria for measuring the quality of an image or the performance of the processing techinque. This study utilizes the variance of prediction error which is computed by substituting the gary level of pixel of another texture field into the two dimensional AR(autoregressive model)model fitted to the texture field, estimate the parameter us-ing the PAA(parameter adaptation algorithm) and design the defect detection filter. Later, we next try to study the defect detection search algorithm.

• Journal of the Architectural Institute of Korea Structure & Construction
• /
• v.33 no.12
• /
• pp.11-18
• /
• 2017

The safety inspection cost of the construction work was based on commercial facilities classified as a single building. Therefore, it is not possible to fully reflect the characteristics of the multi-building construction project such as apartment houses. Therefore, this study suggests a reasonable estimation model that can fully reflect the characteristics of the multi-building construction project. The safety inspection cost estimation model proposed two models such as construction cost ratio method and cost plus fixed fee method. And these models were simulated by the apartment construction work and compared with the current standard. As a result, the current construction cost ratio method has shown that the safety inspection cost tends to be overestimated as the construction size increases. Therefore, the proposed model has reflected characteristics of the multi-building construction project, so that it can reasonably estimate the safety inspection cost more than the current standard.

• Journal of the Korean Institute of Gas
• /
• v.25 no.3
• /
• pp.16-26
• /
• 2021

The global warming problem has arose, the supply eco-friendly vehicles such as HFCEVs is increasing around world and Korea is fully supporting subsidies, tax cut to form an initial market for HFCEVs. The key to the safety of HFCEVs is pressure vessels stored hydrogen, and although these pressure vessels must be inspection regularly, the existing inspection stations are insufficient to meet the demand for inspection. Therefore, it is important to establishment of pressure vessels inspection station for safety management of HFCEVs. In this study, it estimates innovation coefficient, imitation coefficient in Bass model by using electric vehicle sales data, and foretasted the supply of HFCEVs by region & the demand for inspection by region using the Bass diffusion model. As a result, the inspection demand for pressure vessels in HFCEVs in 2040 was 690,759 units, and it was confirmed 191 new inspection stations and 1,124 inspectors were needed to prepare for this.

• Journal of Institute of Control, Robotics and Systems
• /
• v.15 no.8
• /
• pp.772-777
• /
• 2009

The geometric distortion of image is one of the most important parameters that take effect on the accuracy of optical inspection systems. We propose a new correction method of the image distortion to increase the accuracy of PCB inspection systems. The model-free method is applied to correct the randomly distorted image that cannot be represented by mathematical model. To reduce the correction time of inspection system, we newly propose a grid reduction algorithm that minimize the number of grids by the quad-tree approach. We apply the proposed method to a PCB inspection system, and verify its usefulness through experiments using actual inspection images.

• Industrial Engineering and Management Systems
• /
• v.4 no.2
• /
• pp.123-128
• /
• 2005

The author derives a general explicit formula and presents an heuristic algorithm for solving Baker’s model. The examples show that this new approximate solution procedure for determining near optimum inspection intervals is more accurate than the ones suggested by Chung (1993) and Vaurio (1994), and is more efficient computationally than the one suggested by Hariga (1996). The construction and solution of the simplest profit model for an exponential failure distribution were presented in Baker (1990), and approximate analytical results were obtained by Chung (1993) and Vaurio (1994). The author will therefore mainly devote the following discussion to the problem of further approximating optimum inspection intervals.