• Title/Summary/Keyword: the process variables

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A Study of Bending Process for Development of Subframe by Hydroforming (일체화 성형 서브프레임 개발을 위한 벤딩 공정의 영향성 연구)

  • 서창희;이우식;김헌영;임희택
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.05a
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    • pp.262-265
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    • 2003
  • In the present study, subframe was developed using hydroforming technology. The manufacturing process for subframe consists of tube bending, pre-forming and hydroforming. The effects of bending process for manufacturing hydroformed subframe were researched. And the variables of bending process were studied by FEM simulation. The bending method is rotary draw bending that is the most popular, cost-effective bending method for thin walled tubes.

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Measurement of Food Process Variables with Microcomputer (마이크로컴퓨터를 이용한 식품공정의 변수계측)

  • Kang, Jun-Soo;Suh, Myung-Gyo;Chung, Shin-Kyo;Choi, Jong-Uck
    • Korean Journal of Food Science and Technology
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    • v.24 no.6
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    • pp.524-527
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    • 1992
  • To measure of important variables such as temperature, weight, and relative humidity in food processing process, computer-aided data acquisition system was composed of 16 bit microcomputer and PCL-711S interface board. Process variables in dehydration and storage of food were measured through sensors, converters, and computer system which were operated by the PC-LabDAS software for data acquisition, process control, and data analysis. The relationship between measured values of process variables and the output voltages of ADC showed more than 0.99 in $r^2$ value. Response time of sensors was enough fast to measure minute values changed in a moment.

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A Central Limit Theorem for the Linear Process in a Hilbert Space under Negative Association

  • Ko, Mi-Hwa
    • Communications for Statistical Applications and Methods
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    • v.16 no.4
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    • pp.687-696
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    • 2009
  • We prove a central limit theorem for the negatively associated random variables in a Hilbert space and extend this result to the linear process generated by negatively associated random variables in a Hilbert space. Our result implies an extension of the central limit theorem for the linear process in a real space under negative association to a simplest case of infinite dimensional Hilbert space.

Experimental Investigation on Relationship of Winding Process Variables and Mechanical Properties for Filament Wound Composites (필라멘트와인딩 복합재의 기계적 특성과 와인딩시 공정변수와의 관계에 대한 실험적 고찰)

  • 윤성호;김준영;황태경
    • Journal of the Korean Society of Propulsion Engineers
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    • v.3 no.2
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    • pp.56-65
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    • 1999
  • The relationship of the winding process variables and the mechanical properties of filament wound composites is investigated experimentally. The winding process variables considered are the fiber tensions and the fiber ends. The filament wound ring specimens are fabricated using 3-axis controlled filament winding machine. Two types of carbon fibers, TZ-507 and IZ-40, are used as reinforcements and epoxy for filament winding is used as resin. During the winding process, the fiber tensions are varied from 0.5kgf to 3.0kgf, and the number of the fiber ends are varied from 1 to 6. The fiber volume fractions and the void contents for the ring specimens are measured through the resin digestion. The mechanical properties of the ring specimens are also evaluated by the split disk test. The test results show that the winding process variables affect the fiber volume fractions and the void contents of the ring specimens, which result in the variation of the tensile properties of the ring specimens. Therefore, suitable winding process variables should be applied to maximize the structural performance and the productivity for filament wound structures.

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A Study on the Optimization for a V-groove GMA Welding Process Using a Dual Response Method (듀얼 반응표면법을 이용한 V-그루브 GMA 용접공정 최적화에 관한 연구)

  • Park, Hyoung-Jin;Ahn, Seung-Ho;Kang, Mun-Jin;Rhee, Se-Hun
    • Journal of Welding and Joining
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    • v.26 no.2
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    • pp.85-91
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    • 2008
  • In general, the quality of a welding process tends to vary with depending on the work environment or external disturbances. Hence, in order to achieve the desirable quality of welding, we should have the optimal welding condition that is not significantly affected by these changes in the environment or external disturbances. In this study, we used a dual response surface method in consideration of both the mean output variables and the standard deviation in order to optimize the V-groove arc welding process. The input variables for GMA welding process with the dual response surface are welding voltage, welding current and welding speed. The output variables are the welding quality function using the shape factor of bead geometry. First, we performed welding experiment on the interested area according to the central composite design. From the results obtained, we derived the regression model on the mean and standard deviation between the input and output variables of the welding process and then obtained the dual response surface. Finally, using the grid search method, we obtained the input variables that minimize the object function which led to the optimal V-groove arc welding process.

The Selection of Optimal Process Variables in UV-Vacuum Casting (UV-Vaccum Casting의 최적 공정 변수 선정)

  • Kim, T. W.;Woo, S. M.;Lee, S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.453-456
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    • 2000
  • This paper presents experimental results on selecting optimal process parameters for UV-Vaccum casting. The UV-Vacuum casting is a relatively new process that allows very rapid mold preparation and part duplication via UV curing. Effect of various process variables such as pressure and temperature on mold strength and part accuracy was evaluated by using Taguchi method.

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Shape Optimization of Waveguide Tee Junction in H-plane (자기 평면 도파관 소자의 최적형상설)

  • 이홍배;한송엽;천창열
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.43 no.6
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    • pp.1020-1026
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    • 1994
  • This paper presents a technique to optimize the shape of waveguide components in H-plane. The technique utilizes the numerical optimization process which employs the vector finite element method. In the optimization process, the sensitivity of an objective function with respect to design variables is computed by introducting adjoint variables, which makes the computation easy. The steepest descent method is then employed to update design variables. As a numerical example, an H-plane waveguide teejunction was considered to obtain optimized shape. Comparison between the initial and optimized shape was made.

The Effects of the Computer Aided Innovation Capabilities on the R&D Capabilities: Focusing on the SMEs of Korea (Computer Aided Innovation 역량이 연구개발역량에 미치는 효과: 국내 중소기업을 대상으로)

  • Shim, Jae Eok;Byeon, Moo Jang;Moon, Hyo Gon;Oh, Jay In
    • Asia pacific journal of information systems
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    • v.23 no.3
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    • pp.25-53
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    • 2013
  • This study analyzes the effect of Computer Aided Innovation (CAI) to improve R&D Capabilities empirically. Survey was distributed by e-mail and Google Docs, targeting CTO of 235 SMEs. 142 surveys were returned back (rate of return 60.4%) from companies. Survey results from 119 companies (83.8%) which are effective samples except no-response, insincere response, estimated value, etc. were used for statistics analysis. Companies with less than 50billion KRW sales of entire researched companies occupy 76.5% in terms of sample traits. Companies with less than 300 employees occupy 83.2%. In terms of the type of company business Partners (called 'partners with big companies' hereunder) who work with big companies for business occupy 68.1%. SMEs based on their own business (called 'independent small companies') appear to occupy 31.9%. The present status of holding IT system according to traits of company business was classified into partners with big companies versus independent SMEs. The present status of ERP is 18.5% to 34.5%. QMS is 11.8% to 9.2%. And PLM (Product Life-cycle Management) is 6.7% to 2.5%. The holding of 3D CAD is 47.1% to 21%. IT system-holding and its application of independent SMEs seemed very vulnerable, compared with partner companies of big companies. This study is comprised of IT infra and IT Utilization as CAI capacity factors which are independent variables. factors of R&D capabilities which are independent variables are organization capability, process capability, HR capability, technology-accumulating capability, and internal/external collaboration capability. The highest average value of variables was 4.24 in organization capability 2. The lowest average value was 3.01 in IT infra which makes users access to data and information in other areas and use them with ease when required during new product development. It seems that the inferior environment of IT infra of general SMEs is reflected in CAI itself. In order to review the validity used to measure variables, Factors have been analyzed. 7 factors which have over 1.0 pure value of their dependent and independent variables were extracted. These factors appear to explain 71.167% in total of total variances. From the result of factor analysis about measurable variables in this study, reliability of each item was checked by Cronbach's Alpha coefficient. All measurable factors at least over 0.611 seemed to acquire reliability. Next, correlation has been done to explain certain phenomenon by correlation analysis between variables. As R&D capabilities factors which are arranged as dependent variables, organization capability, process capability, HR capability, technology-accumulating capability, and internal/external collaboration capability turned out that they acquire significant correlation at 99% reliability level in all variables of IT infra and IT Utilization which are independent variables. In addition, correlation coefficient between each factor is less than 0.8, which proves that the validity of this study judgement has been acquired. The pair with the highest coefficient had 0.628 for IT utilization and technology-accumulating capability. Regression model which can estimate independent variables was used in this study under the hypothesis that there is linear relation between independent variables and dependent variables so as to identify CAI capability's impact factors on R&D. The total explanations of IT infra among CAI capability for independent variables such as organization capability, process capability, human resources capability, technology-accumulating capability, and collaboration capability are 10.3%, 7%, 11.9%, 30.9%, and 10.5% respectively. IT Utilization exposes comprehensively low explanatory capability with 12.4%, 5.9%, 11.1%, 38.9%, and 13.4% for organization capability, process capability, human resources capability, technology-accumulating capability, and collaboration capability respectively. However, both factors of independent variables expose very high explanatory capability relatively for technology-accumulating capability among independent variable. Regression formula which is comprised of independent variables and dependent variables are all significant (P<0.005). The suitability of regression model seems high. When the results of test for dependent variables and independent variables are estimated, the hypothesis of 10 different factors appeared all significant in regression analysis model coefficient (P<0.01) which is estimated to affect in the hypothesis. As a result of liner regression analysis between two independent variables drawn by influence factor analysis for R&D capability and R&D capability. IT infra and IT Utilization which are CAI capability factors has positive correlation to organization capability, process capability, human resources capability, technology-accumulating capability, and collaboration capability with inside and outside which are dependent variables, R&D capability factors. It was identified as a significant factor which affects R&D capability. However, considering adjustable variables, a big gap is found, compared to entire company. First of all, in case of partner companies with big companies, in IT infra as CAI capability, organization capability, process capability, human resources capability, and technology capability out of R&D capacities seems to have positive correlation. However, collaboration capability appeared insignificance. IT utilization which is a CAI capability factor seemed to have positive relation to organization capability, process capability, human resources capability, and internal/external collaboration capability just as those of entire companies. Next, by analyzing independent types of SMEs as an adjustable variable, very different results were found from those of entire companies or partner companies with big companies. First of all, all factors in IT infra except technology-accumulating capability were rejected. IT utilization was rejected except technology-accumulating capability and collaboration capability. Comprehending the above adjustable variables, the following results were drawn in this study. First, in case of big companies or partner companies with big companies, IT infra and IT utilization affect improving R&D Capabilities positively. It was because most of big companies encourage innovation by using IT utilization and IT infra building over certain level to their partner companies. Second, in all companies, IT infra and IT utilization as CAI capability affect improving technology-accumulating capability positively at least as R&D capability factor. The most of factor explanation is low at around 10%. However, technology-accumulating capability is rather high around 25.6% to 38.4%. It was found that CAI capability contributes to technology-accumulating capability highly. Companies shouldn't consider IT infra and IT utilization as a simple product developing tool in R&D section. However, they have to consider to use them as a management innovating strategy tool which proceeds entire-company management innovation centered in new product development. Not only the improvement of technology-accumulating capability in department of R&D. Centered in new product development, it has to be used as original management innovative strategy which proceeds entire company management innovation. It suggests that it can be a method to improve technology-accumulating capability in R&D section and Dynamic capability to acquire sustainable competitive advantage.

Discretization Method Based on Quantiles for Variable Selection Using Mutual Information

  • CHa, Woon-Ock;Huh, Moon-Yul
    • Communications for Statistical Applications and Methods
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    • v.12 no.3
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    • pp.659-672
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    • 2005
  • This paper evaluates discretization of continuous variables to select relevant variables for supervised learning using mutual information. Three discretization methods, MDL, Histogram and 4-Intervals are considered. The process of discretization and variable subset selection is evaluated according to the classification accuracies with the 6 real data sets of UCI databases. Results show that 4-Interval discretization method based on quantiles, is robust and efficient for variable selection process. We also visually evaluate the appropriateness of the selected subset of variables.

A study on the Processing Variables of Rapid Prototyping using Sheet Metal (금속박판을 이용한 쾌속조형의 공정변수에 관한 연구)

  • 이상찬;박정남;양동열
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.42-45
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    • 2003
  • The purpose of this study is the development or the extensive Rapid Prototyping Technique. which can resolve the long-term manufacturing process, shrinkage and deformation occurring rapid prototyping technique. To begin with. the various specimens for tensile were manufactured on the basis of this modeling technology. Then, many kinds of the laminate pieces for the test were made by using the sheet metals lmm and 1.5mm thickness which is composed of the same ingredient. The tensile specimen were manufactured by changing the process variables, Such as electric current, pressure and resistance welding time for the Rapid Prototyping with metal sheet. And then by using the Taguchi method. The interrelation between the specimen and mechanical properties were determined and the system for the optimum process variable organized.

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