• Title/Summary/Keyword: Quality Inspections

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Development of A Lot Quality Assurance and Inspection Cost Estimation System for Process-Centered Inspections (공정 중심의 검사 방식에 대한 로트 품질보증 및 검사비용 추정 시스템 개발)

  • Lee, Do-Kyung;Lee, Seung-Woo
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.29 no.1
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    • pp.34-40
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    • 2006
  • Many producers put sampling inspection policy into the way of their convenience. Examples of the convenience are irregular lot size and too small sample size. Because they don't use a standard sampling inspection policy, they can not guarantee the quality level of their products. In this study, we developed a user-centered design program which can calculate the AOQL of their products to their buyers in the case of irregular lot size and too small sample size. Also this program propose a linear inspection cost by Hald's model.

A Study on the manufacturing process using the sensitivity analysis of stochastic network (감도분석에 의한 제조공정연구)

  • 박기주
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.24 no.63
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    • pp.65-77
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    • 2001
  • A more technical perspective is needed in estimating the effect of the Manufacturing Process for improving the Productivity, there are many statistical evaluation methods, convenience sampling, frequencies, histogram, QC seven tools, control chart etc. It is more important for the companies to use six sigma to reduce defective and improve the process control than the technical definition as a disciplined quantitative approach for improvement of process control and a new way of quality innovation. Process network analysis is a technique which has the potentiality for a wide use to improve the manufacturing process which other techniques can't be used to analyze effectively. It has some problems to analyze the process with feedback loops. The branch probabilities during quality inspections depend upon the number of times the product has been rejected. This paper presents how to improve the manufacturing process by statistical process control using branch probabilities, Moment Generating Function(MGF) and Sensitivity Equation.

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Determination of the Optimal Specification Limits for Complete Inspection Plans (전수검사를 위한 최적규격한계 설정)

  • Hong, Sung-Hoon;Kim, Sang-Boo
    • Journal of Korean Institute of Industrial Engineers
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    • v.21 no.2
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    • pp.255-265
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    • 1995
  • Due to advances in automated manufacturing systems and automatic inspection equipment, complete inspection has drown increased attention recently and has become a widespread practice. In a complete inspection plan all of the items are subject to acceptance inspection If an item fails to meet the predetermined specifications, it is rejected. In this paper, economic complete inspection plans are developed in situations where rejected items are reworked Complete inspections based on the performance variable of interest or a variable which is correlated with the performance variable are considered. Cost models are constructed which involve cost incurred by imperfect quality rework cast and quality inspection cost Methods of finding the optimal complete inspection plans are presented and numerical examples are given.

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Design of Accelerated Life Test Plans for the Lognormal Failure Distribution under Intermittent Inspection (대수정규분포와 간헐적 검사하에서 가속수명시험방식의 설계)

  • Seo, Sun-Keun;Cho, Ho-Sung
    • Journal of Korean Society for Quality Management
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    • v.24 no.2
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    • pp.25-43
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    • 1996
  • This paper presents the optimal and practical constant-stress accelerated life test plans for the lognormal lifetime distribution tinder assumptions of intermittent inspection and Type-I censoring. In an optimal plan, the low stress level and the proportions of test units allocated at each stress are determined under given inspection scheme and number of inspections such that the asymptotic variance of the maximum likelihood estimator of a certain quantile at use condition is minimized. Although the practical plan adopts the same design criterion, it involves three rather than two overstress levels in order to compromise the practical deficiencies of the optimal plan. Computational experiments are conducted to choose an allocation plan and a inspection scheme of the practical plan and to compare with test plans over a range of parameter values.

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A Study on the Preservation and the Deformation of Regional Historic Buildings - On the Basis of Historic Buildings designated by Kyong-Nam Provincial Government - (지방(地方) 건축문화재(建築文化財)의 보존(保存)과 변형실태(變形實態)에 관한 조사연구(調査硏究) - 경상남도(慶尙南道)의 유형문화재(有形文化財)를 중심으로)

  • Kang, Young Hwan
    • Journal of architectural history
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    • v.4 no.1
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    • pp.9-28
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    • 1995
  • How have they preserved the regional historic buildings in Korea? Do they preserve the original value as a historic building. Are there any artificial deformations deteriorating the quality of the buildings? Is the regional system for preservation effective agalnst the artificial deformations of the buildings? These questions are involved in the purposes of this paper. I investigated the historic buildings designated by Kyong-Nam provincial government. As the resuit, variouse patterns of artificial deformation were found. I found that the deformations may deteriorate the original quality of historic building, and it is related somehow to the limitations of regional system for preservation. So I suggest some alternative ideas for preserving the quality of historic buildings against artificial deformation : a. Present system for preservation is not effective for preserving various architectural value such as urban context and landscape, site planning techniques, function of a space, etc. Regional system should be revised for preserving their architectural value or meaning. b. Historic buildings should be classified and should have proper protecting area according to each architectural values or meanings, respectibly: Historic buildings with Urban context and landscape Historic buildings as a part of a complex Historic buildings as a behavorial setting. c. Historic buildings should be graded based on their quality. And standard and criteria for acceptable deformations should be established. d. Periodical inspections by experts should be carried out to check out the deformation.

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A Case Study on the Target Sampling Inspection for Improving Outgoing Quality (타겟 샘플링 검사를 통한 출하품질 향상에 관한 사례 연구)

  • Kim, Junse;Lee, Changki;Kim, Kyungnam;Kim, Changwoo;Song, Hyemi;Ahn, Seoungsu;Oh, Jaewon;Jo, Hyunsang;Han, Sangseop
    • Journal of Korean Society for Quality Management
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    • v.49 no.3
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    • pp.421-431
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    • 2021
  • Purpose: For improving outgoing quality, this study presents a novel sampling framework based on predictive analytics. Methods: The proposed framework is composed of three steps. The first step is the variable selection. The knowledge-based and data-driven approaches are employed to select important variables. The second step is the model learning. In this step, we consider the supervised classification methods, the anomaly detection methods, and the rule-based methods. The applying model is the third step. This step includes the all processes to be enabled on real-time prediction. Each prediction model classifies a product as a target sample or random sample. Thereafter intensive quality inspections are executed on the specified target samples. Results: The inspection data of three Samsung products (mobile, TV, refrigerator) are used to check functional defects in the product by utilizing the proposed method. The results demonstrate that using target sampling is more effective and efficient than random sampling. Conclusion: The results of this paper show that the proposed method can efficiently detect products that have the possibilities of user's defect in the lot. Additionally our study can guide practitioners on how to easily detect defective products using stratified sampling

Selection of Manageable Diseases for Quality Assessment in Korean Medicine by Delphi Method (한방분야 적정성 평가 대상 질환 선정을 위한 전문가 Delphi 조사)

  • Park, Chang-Hyun;Lim, Hyung-Ho
    • Journal of Korean Medicine Rehabilitation
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    • v.26 no.3
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    • pp.129-141
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    • 2016
  • Objectives As awareness of the public about Korean medicine health care and the social demand about improvement for quality of health care service is constantly rising, the quality evaluation of Korean medicine health care service is needed to improve the quality. Through trial of Delphi method, we tried to set the priority in short, medium, long term among the disease which is the subject of quality assessment. Methods Carrying out the delphi survey to 50 experts of korean medicine who were recommended by the 41 member societies of Korean medicine and related organizations, we selected final candidates for quality assessment. It is composed with total 2 rounds, and we investigated the priority in three aspects; the importance of the matter, possibility quality assessment, potential about if there's any chance of improvement. Results By delphi method, we set the priority of quality assessment. Base on the result of the second round, we classified importance of the questions into above average, average, below average, and categorized items as short, medium, long term according on the final priority. We classified of musculoskeletal diseases and diseases of connective tissues and musculoskeletal injury as short term and cerebrovascular disease and disease of nerve system and malignant neoplasm as medium term, disease of digestive organs and diseases, symptoms and abnormal findings in clinical field or inspections which are not categorized as long term. Conclusions We set the subjects of quality assessment by delphi survey by experts, and classified into short, medium, long term. Further research is necessary for execution the Quality Assessment to each of the candidate. Also, we can send feedback to medical institution base on the result of Quality Assessment. then it would be able to induce the improvement in quality of medical institution by itself.

The Outline of Han River Basin Environmental master Plan Project (한강유역 환경보전 종합계획 사업의 개요)

  • 이선환
    • Journal of the Korean Professional Engineers Association
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    • v.15 no.1
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    • pp.46-50
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    • 1982
  • Following rapid industrial development and urbanization in Korea, there is a need for the Government to implement effective control of pollution and to undertake specific schemes in areas where pollution of the environment is severe. In response to this need, Government of Korea prepare Han River Basin Environmental Master Plan Project for water, air, solid waste to cover environmental protection of the Han River Basin. The Project area is approximately 27,000 sq. Km extending over Seoul, Kyunggi, Kwangwon, Chungbuk Province. The total population of Master Plan Project area is approximately 11.6 million, or one-third of the total population of Korea. There are about 8,000 industries, including those located in 16 industrial complexes, in the project area. The scope of work and terms of reference are the following: (1) A Summary of existing land use and forecasts for changes in land use by the year 2,000. (2) Emission inventories for air, waste water, and solid wastes. (3) Forecasts of future population growth patterns and pollution loadings. (4) Identification of specific projects needs to reduce pollution levels and satisfy the environmental quality standards. (5) A Program of enforcement to include (i) self monitoring, and (ii) governmental inspections and surveillance. (6) A program for quality improvement and quality assurance of environmental measurements. (7) Reports summarizing all data collected analyzed during the study. (8) Conceptual design and feasibility studies, including cost estimates, for needed pollution control projects. (9) A financial plan for future detailed design and construction of public facilities, for financial incentives to industry, and for user charges for industrial use of public treatment of disposal works.

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Quality assurance algorithm using fuzzy reasoning for resistance spot weldings (퍼지추론을 이용한 저항 점용접부위의 품질평가 알고리듬)

  • Kim, Joo-Seok;Lee, Jae-Ik;Lee, Sang-ryong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.3
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    • pp.644-653
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    • 1998
  • In resistance spot weld, the assurance of weld quality has been a long-standing problem. Since the weld nuggets if resustance spot welding form between the workpieces, visual detection of defects in usually impossible. Welding quality of resistance spot welding can be verified by non destructive and destructive inspections such as X-Ray inspection and testing of weld strength. But these tests, in addition to being time-consuming and costly, can entail risks due to sampling basis. The purpose of this study is the development of the monitoring system based on fuzzy inference, aimed at diagonosis of quality in resistance spot welding. The fuzzy inference system consists of fuzzy input variables, fuzzy membership functions and fuzzy rules. For inferring the welding quality(strength), the experimental data of the spot welding were acquired in various welding conditions with the monitoring system designed. Some fuzzy input variables-maximum, slop and difference values of electrode movement signals-were extracted from the experimental data. It was confirmed that the fuzzy inference values of strength have a .${\pm}$5% error in comparison with actual values for the selected welding conditions(9-10.5KA, 10-14 cycle, 250-300 $kg_f$). This monitoring system can be useful in improving the quality assurance and reliability of the resistance spot welding process.

Effect of Environmental Change in Radiography Room and Psychological Impact on Young Patients (심리적 안정을 고려한 촬영실 내부 환경변화가 검사에 미치는 영향; 유아 방사선검사의 불안감 해소 중심으로)

  • Kim, Seon-Chil;Seok, Eun-Jo
    • Journal of radiological science and technology
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    • v.30 no.1
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    • pp.61-65
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    • 2007
  • The attempt to enhance the environment of hospitals has increased recently to minimize young patients' anxiety about tests and inspections. This gives more satisfaction with the medical service to kids and young patients. The department of radiology endeavors to improve the conditions of existing radiography rooms to help young patients psychologically feel relaxed. This facilitates the process of inspections. This paper examines the relationship between the environment of radiography rooms and its effect on young patients' state of mind. 94 patients at the age of five were observed before and after the improvement of environment of the hospital. Positive results about the psychological state of the young patients were shown after the change of the environment. The result of this paper gives an idea that the modification of hospital environment has a critical importance to the young patients' psychological state. By this conclusion it may help to improve the quality of the medical service.

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