• Title/Summary/Keyword: Selection Process

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Characteristic Analysis and Selection of Process Parameters in Direct Rolling Processes (직접압연공정의 특성해석 및 공정변수 선정)

  • 박영준;조형석;이원호;강태욱
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.04a
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    • pp.384-388
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    • 1997
  • Recently,direct rolling process has been drawing increasing interests because production cost be greatly reduced by eliminating subsequent hot rolling processes. Such a process has been characterized to prosuce thin steel strip (thickness 1~5mm) directly from molten metal and to skip over the conventional hot rolling processes. However, since there are several process parameters, which affect the quality of product,and their relationship between the parametersare very complex,it is therefore very difficult to realize the process design and the quality control. To overcome these difficulties quantitative relationship between the parameters are investigated through a numerical analysis. Form these results, it is found that solidification final point is the most important paramter which is critical to quality of the strip. Also,the multiple regression model is obtianed to determine their relationship from the solidification final point and roll separating force which can be easily estimated

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A Study on Development of Algorithm for Predicting the Optimized Process Parameters on Bead Geometry (임의의 비드형상을 의한 최적의 공정변수 예측 알고리즘 개발에 관한 연구)

  • 김일수;차용훈;이연신;박창언;손준식
    • Journal of Welding and Joining
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    • v.17 no.4
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    • pp.39-45
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    • 1999
  • The procedure of robotic Gas metal Arc (GMA) welding in order to achieve the optimized bead geometry needs the selection of suitable process parameters such as arc current, welding voltage, welding speed. It is required the relationships between process parameters and bead geometry. The objective of this paper is to develop the algorithm that enables the determination of process parameters from the optimized bead geometry for robotic GMA welding. It depends on the inversion of empirical equations derived from multiple regression analysis of the relationships between the process parameters and the bead dimensions using the least square method. The method not only directly determines those parameters which will give the desired set of bead geometry, but also avoids the need to iterate with a succession of guesses employed Finite Element Method(FEM). These results suggest that process parameter from experimental equation for robotic GMA welding may be employed to monitor and control the bead geometry in real time.

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A Case Study of Six Sigma Project for Improving TIP Life Time in a Spot Welding Process (스폿 용접공정의 TIP 수명 향상을 위한 6시그마 프로젝트 사례)

  • Lee, Min-Koo;Kwag, Hyo-Chang
    • Journal of Korean Society for Quality Management
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    • v.33 no.1
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    • pp.88-98
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    • 2005
  • This paper considers a six sigma project for improving the TIP life time in a spot welding process. The project follows a disciplined process of five phases: define, measure, analyze, improve, and control. A process map is used to identify process input and output variables. Nine key process input variables are selected by using C&E matrix and FMEA, and finally four vital few input variables are selected from analyze phase. The optimum process conditions of the vital few input variables are jointly obtained by maximizing TIP life time using DOE and alternative selection method.

A Study on the Safety Assessment of Zinc Plating Process (아연도금공정의 안전성평가)

  • Rhie, Kwang-Won;Park, Moon-Hee
    • Journal of the Korean Society of Safety
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    • v.18 no.4
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    • pp.148-154
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    • 2003
  • There are now the plating process that have many hazardous factor cause of the using numerous noxious chemical and bad working environments. The purpose of the study is to make a selection of suitable safety evaluation method that can analyze and righteously find with numerous hazardous factor of the plating process. And another purpose is to systematically adjust the risk of plating process by comprehension of the role of process, equipment, and source material. Therefore, these studies are carried out in the following three investigations of this report. The first research understands the injurious human health and environment by analyzing hazardous material based on the MSDS. To evaluate the safety of process and compartment, the second research is proposed the security secure counterproposal by using the FMEA and the HAZOP. The final research is devoted to systematically analyze the hazard by applying for reasonable guide word and doing the HAZOP for hazardous factor in specific process.

A Study on the Fault Process and Equipment Analysis of Plastic Ball Grid Array Manufacturing Using Data-Mining Techniques

  • Sim, Hyun Sik
    • Journal of Information Processing Systems
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    • v.16 no.6
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    • pp.1271-1280
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    • 2020
  • The yield and quality of a micromanufacturing process are important management factors. In real-world situations, it is difficult to achieve a high yield from a manufacturing process because the products are produced through multiple nanoscale manufacturing processes. Therefore, it is necessary to identify the processes and equipment that lead to low yields. This paper proposes an analytical method to identify the processes and equipment that cause a defect in the plastic ball grid array (PBGA) during the manufacturing process using logistic regression and stepwise variable selection. The proposed method was tested with the lot trace records of a real work site. The records included the sequence of equipment that the lot had passed through and the number of faults of each type in the lot. We demonstrated that the test results reflect the real situation in a PBGA manufacturing process, and the major equipment parameters were then controlled to confirm the improvement in yield; the yield improved by approximately 20%.

Model development for site selection considering the characteristics of LNG receiving terminal (LNG 특성을 고려한 저장기지 입지선정 모델 개발)

  • Jeong, Nam Hoon;Liu, An Qi;Hwang, Geon Wook;Jang, Woosik;Han, Seung Heon
    • Korean Journal of Construction Engineering and Management
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    • v.16 no.1
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    • pp.82-91
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    • 2015
  • Recently, due to the increasing concern of environmental factors and low carbon usage, the use of natural gas has been inclining steadily. In order to meet the growing demand of natural gas, government have established strategies to secure the sufficient amount of gas that is mainly used by industries, power generation and residential use by constructing additional receiving terminals for Liquid Natural Gas (LNG). In the process of selecting the optimal site for the terminals, the characteristics of the terminals are not considered where the decision making is done through internal meetings or outsourcing. In respect to site selection, researches are done to derive the factors that are considered for optimal site selection. However, there have not yet been researches in creating a systematic model for analyzing the optimal site selection. To this aim, the paper aims to propose a model for site selection of LNG receiving terminals that considers the characteristics of the terminal construction. Total of 47 factors considered in site selection is derived through interviews with experts and analyzing the previous cases of site selection by various firms. Furthermore, the derived 47 factors are used for the survey for the previous LNG terminals in PT, IC, TY, SC and BR areas where the survey data is analyzed by factor analysis and multiple regression models to depict the optimal site. By applying the model for site selection, practitioners are able to make decisions for site selection in a systematic approach for new candidates of sites.

A study on the perception of landscape through the selection process of Bandopalgyong - eight beautiful scenary in Korea - within Japanese colonial period (일제강점기 반도팔경 선정과정을 통해 본 경관인식)

  • Kim, Hai-Gyeong;An, Kyung-Jin
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.33 no.2
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    • pp.78-88
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    • 2015
  • In the 1920s, the period of cultural governance ruled by Japan, the diverse media were founded and various events were conducted to boost circulation. Under the Japanese colonial period in 1920s, a number of media - newspapers and magazines - were published and often they carried out entertaining events in order to obtain more subscribers. A hobby magazine, Samchunri, for instace, set up a media event to selecting Korea's eight beautiful scenary (Bandopalgyong) for the first edition in 1929. The paper aims to analyse and understand the perception of landscape in 1929 through the media event carried out by Samchunri. In particular, the selection was made by well-known writers within Japanese colonial period 1910 - 1945). The selection process and views from the writers on landscape were analysed; firstly, the selection of Bandopalgyong was carried out by questionnaires to writers in 1929 where Korea is under Japanese colonial rules. The conditions of the selection were unknown; however, the purpose was enlightening the people specially the youngs and introduction of beautiful places in Korea. As a result, views and opinions on Bandopalgyong by the writers were progressed. Secondly, within the Bandopalgyong, the natural landscape areas include Gumgansan(金剛山), Daedonggang(大洞江), Buyeo(扶餘), Gyongju(慶州), Myongsasipri (明沙十里), Haundae(海雲臺), Baekdusan(白頭山), and Choksukru(矗石樓). Those chosen places were not cohesive nor did not have any consistant reasons to be chosen in terms of size and location; however, some writers claimed that there were other places to match the chosen ones and therefore, the selection process was highly dependent on access (i.e. transport). Thirdly, the travelogue on Baekdusan and Nackwhaam(洛花岩) illustrated interesting views on landscape in particular. Baekdusan landscape were described in overlaping with long history and national soul. In the Nackwhaam travelogue, it described 'Buyeo (夫餘) was an ancient capital of Backjae Dynasty and empty place' as well as denying Chosun Dynasty. It was assumed that the two places weren't visited but rewritten with existing literatures. Fourthly, edited by Kim Dong Whan, a travelogue style book, 'Bandosanha' was published in 1941. It did repeat the selection of Bandopalgyong, but this time, it was classified the eight beautiful landscape into two categories; historic/cultural places and natural landscape. This paper was able to analyse and understand the perception of landscape in 1929 through the travelogue of Samchunri. It is an empirical study on the process and perception on Korea landscape under Japanese colonical period by views of the selected writers.

Self-optimizing feature selection algorithm for enhancing campaign effectiveness (캠페인 효과 제고를 위한 자기 최적화 변수 선택 알고리즘)

  • Seo, Jeoung-soo;Ahn, Hyunchul
    • Journal of Intelligence and Information Systems
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    • v.26 no.4
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    • pp.173-198
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    • 2020
  • For a long time, many studies have been conducted on predicting the success of campaigns for customers in academia, and prediction models applying various techniques are still being studied. Recently, as campaign channels have been expanded in various ways due to the rapid revitalization of online, various types of campaigns are being carried out by companies at a level that cannot be compared to the past. However, customers tend to perceive it as spam as the fatigue of campaigns due to duplicate exposure increases. Also, from a corporate standpoint, there is a problem that the effectiveness of the campaign itself is decreasing, such as increasing the cost of investing in the campaign, which leads to the low actual campaign success rate. Accordingly, various studies are ongoing to improve the effectiveness of the campaign in practice. This campaign system has the ultimate purpose to increase the success rate of various campaigns by collecting and analyzing various data related to customers and using them for campaigns. In particular, recent attempts to make various predictions related to the response of campaigns using machine learning have been made. It is very important to select appropriate features due to the various features of campaign data. If all of the input data are used in the process of classifying a large amount of data, it takes a lot of learning time as the classification class expands, so the minimum input data set must be extracted and used from the entire data. In addition, when a trained model is generated by using too many features, prediction accuracy may be degraded due to overfitting or correlation between features. Therefore, in order to improve accuracy, a feature selection technique that removes features close to noise should be applied, and feature selection is a necessary process in order to analyze a high-dimensional data set. Among the greedy algorithms, SFS (Sequential Forward Selection), SBS (Sequential Backward Selection), SFFS (Sequential Floating Forward Selection), etc. are widely used as traditional feature selection techniques. It is also true that if there are many risks and many features, there is a limitation in that the performance for classification prediction is poor and it takes a lot of learning time. Therefore, in this study, we propose an improved feature selection algorithm to enhance the effectiveness of the existing campaign. The purpose of this study is to improve the existing SFFS sequential method in the process of searching for feature subsets that are the basis for improving machine learning model performance using statistical characteristics of the data to be processed in the campaign system. Through this, features that have a lot of influence on performance are first derived, features that have a negative effect are removed, and then the sequential method is applied to increase the efficiency for search performance and to apply an improved algorithm to enable generalized prediction. Through this, it was confirmed that the proposed model showed better search and prediction performance than the traditional greed algorithm. Compared with the original data set, greed algorithm, genetic algorithm (GA), and recursive feature elimination (RFE), the campaign success prediction was higher. In addition, when performing campaign success prediction, the improved feature selection algorithm was found to be helpful in analyzing and interpreting the prediction results by providing the importance of the derived features. This is important features such as age, customer rating, and sales, which were previously known statistically. Unlike the previous campaign planners, features such as the combined product name, average 3-month data consumption rate, and the last 3-month wireless data usage were unexpectedly selected as important features for the campaign response, which they rarely used to select campaign targets. It was confirmed that base attributes can also be very important features depending on the type of campaign. Through this, it is possible to analyze and understand the important characteristics of each campaign type.

Considering the Multi-Purpose Display Designed for Aircraft Lightning Protection (낙뢰보호를 고려한 항공기용 다목적 디스플레이 설계)

  • Cheon, Young-Ho;Lee, Seoung-Pil;Park, Jun-Hyeon
    • Journal of Advanced Navigation Technology
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    • v.18 no.5
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    • pp.445-454
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    • 2014
  • In this paper, we introduce measures designed content for RTCA DO-160 F, Section 22 tests performed to verify the effects of indirect lightning and testing process of the test was carried out in the multi-purpose display certification process. This is referred to as indirect effects of lightning capability of an aircraft having electrical electronic equipment failure or damage to bring lightning induced voltages. In order to protect the avionics from lightning indirect effects of these aircraft are analyzing the effects of lightning strikes on aircraft and aircraft systems and interior design needs protection against the threat on their part. In this paper, we introduce RTCA DO-160 F, component selection process according to Section 22 category selection method and the selected level for determining the level of such measures for protection against lightning of multipurpose display for this aircraft. It also introduces the actual test process to confirm that the designed effectiveness of the selected part. We expect a good example of the lightning planned for future development of measures designed avionics through each step of the process introduced this.

Concept Optimization for Mechanical Product Using Genetic Algorithm

  • Huang Hong Zhong;Bo Rui Feng;Fan Xiang Feng
    • Journal of Mechanical Science and Technology
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    • v.19 no.5
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    • pp.1072-1079
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    • 2005
  • Conceptual design is the first step in the overall process of product design. Its intrinsic uncertainty, imprecision, and lack of information lead to the fact that current conceptual design activities in engineering have not been computerized and very few CAD systems are available to support conceptual design. In most of the current intelligent design systems, approach of principle synthesis, such as morphology matrix, bond graphic, or design catalogues, is usually adopted to deal with the concept generation, in which optional concepts are generally combined and enumerated through function analysis. However, as a large number of concepts are generated, it is difficult to evaluate and optimize these design candidates using regular algorithm. It is necessary to develop a new approach or a tool to solve the concept generation. Generally speaking, concept generation is a problem of concept synthesis. In substance, this process of developing design candidate is a combinatorial optimization process, viz., the process of concept generation can be regarded as a solution for a state-place composed of multi-concepts. In this paper, genetic algorithm is utilized as a feasible tool to solve the problem of combinatorial optimization in concept generation, in which the encoding method of morphology matrix based on function analysis is applied, and a sequence of optimal concepts are generated through the search and iterative process which is controlled by genetic operators, including selection, crossover, mutation, and reproduction in GA. Several crucial problems on GA are discussed in this paper, such as the calculation of fitness value and the criteria for heredity termination, which have a heavy effect on selection of better concepts. The feasibility and intellectualization of the proposed approach are demonstrated with an engineering case. In this work concept generation is implemented using GA, which can facilitate not only generating several better concepts, but also selecting the best concept. Thus optimal concepts can be conveniently developed and design efficiency can be greatly improved.