• Title/Summary/Keyword: Process Re-engineering

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An Empirical Analysis of a Process Design Considering Worker's Cognition (작업자의 인지를 고려한 공정 설계에 대한 실증 연구)

  • Kim, Yearnmin
    • Journal of Korean Institute of Industrial Engineers
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    • v.42 no.2
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    • pp.80-85
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    • 2016
  • This study suggests a process design using cognitive processes. Job characteristic model for job design and recent cognitive engineering studies for process design are reviewed briefly. By using these concepts, the lean production system is re-interpreted in terms of cognitive engineering and the latent dimensions of the lean production system are revealed as the application of cognitive engineering principles. An integrated process design framework for cognitive manufacturing system using job characteristic model is suggested for the effective design of manufacturing system. Propositions for empirical analysis of this model are also analyzed through a questionnaire survey. Propositions are (1) experiential cognition and motivation potential affect the ability, role perception, and need for achievement of the operator in the manufacturing system, (2) the ability, role perception, and need for achievement of the operator affect the job performance. Both propositions are supported by correlation analysis and path analysis.

Adaptive Lattice Step-Size Algorithm for Narrowband Interference Suppression in DS/CDMA Systems

  • Benjangkaprasert, Chawalit;Teerasakworakun, Sirirat;Jorphochaudom, Sarinporn;Janchitrapongvej, Kanok
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.2087-2089
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    • 2003
  • The presence of narrowband interference (NBI) in Direct-sequence code division multiple access (DS/CDMA) systems is an inevitable problem when the interference is strong enough. The improvement in the system performance employs by adaptive narrowband interference suppression techniques. Basically there have been two types of method for narrowband interference suppression estimator/subtracter approaches and transform domain approaches. In this paper the focus is on the type of estimator/subtracter approaches. However, the binary direct sequence (DS) signal, that acts as noise in the prediction process is highly non-Gaussian. The case of a Gaussian interferer with known in an autoregressive (AR) signal or a digital signal and also in a sinusoidal signal (Tone) that included in is paper. The proposed NBI suppression is presence in an adaptive IIR notch filter for lattice structure and more powerful by using a variable step-size algorithm. The simulation results show that the proposed algorithm can significantly increase the convergence rate and improved system performance when compare with adaptive least mean square algorithm (LMS).

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Manufacturing and Thermal Process Optimization of Ag-paste for Fabricating High Efficiency Mono-Si Solar Cell (고효율 단결정 Si 태양전지 제작을 위한 은 페이스트의 제조 및 열 공정 최적화)

  • Pi, Ji-Hee;Kim, Sung-Jin;Son, Chang-Rok;Kweon, Soon-Yong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.2
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    • pp.144-150
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    • 2013
  • A New Ag-pastes were developed for integrating the high efficiency mono-Si solar cell. The pastes were the mixture of 84 wt% Ag, 2 wt% glass frit, 11 wt% solvent of buthyl cabitol acetate, and 3 wt% additives. After fabricating the Ag-pastes by using a 3-roll mill, they were coated on a $SiN_x$/n+/p- stacks of a commercial mono-Si solar cell. And the post-thermal process was also optimized by varying the process conditions of peak temperature. The optimized solar cell efficiency on a 6-inch mono-Si wafer was 18.28%, which was the one of the world best performances. It meaned that the newly developed Ag-paste could be adopted to fabricate a commercial bulk Si solar cell.

The Study on Fabrication and Sound Absorption Properties of Al-Zn-Mg-Cu Alloy Foams (Al-Zn-Mg-Cu 발포합금 제조 및 흡음특성에 관한 연구)

  • Jeong, Seung-Reung;Hur, Bo-Young
    • Journal of Korea Foundry Society
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    • v.31 no.3
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    • pp.145-151
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    • 2011
  • Metallic foam has been known as a functional material which can be used for absorption properties of energy and sound. The unique characteristics of Al foam of mechanical, acoustic, thermal properties depend on density, cell size distribution and cell size, and these characteristics expected to apply industry field. Al-Zn-Mg-Cu alloy foams was fabricated by following process; firstly melting the Al alloy, thickening process of addition of Ca granule to increased of viscosity, foaming process of addition of titanium hydride powder to make the pores, holding in the furnace to form of cooling down to the room temperature. Metal foams with various porosity level were manufactured by change the foaming temperature. Compressive strength of the Al alloy foams was 2 times higher at 88% porosity and 1.2 times higher at 92% porosity than pure Al foams. It's sound and vibration absorption coefficient were higher than pure Al foams and with increasing porosity.

Thermoelectric and Transport Properties of FeV1-xTixSb Half-Heusler System Synthesized by Controlled Mechanical Alloying Process

  • Hasan, Rahidul;Ur, Soon-Chul
    • Electronic Materials Letters
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    • v.14 no.6
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    • pp.725-732
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    • 2018
  • The thermoelectric and transport properties of Ti-doped FeVSb half-Heusler alloys were studied in this study. $FeV_{1-x}Ti_xSb$ (0.1 < x < 0.5) half-Heusler alloys were synthesized by mechanical alloying process and subsequent vacuum hot pressing. After vacuum hot pressing, a near singe phase with a small fraction of second phase was obtained in this experiment. Investigation of microstructure revealed that both grain and particle sizes were decreased on doping which would influence on thermal conductivity. No foreign elements pick up from the vial was seen during milling process. Thermoelectric properties were investigated as a function of temperature and doping level. The absolute value of Seebeck coefficient showed transition from negative to positive with increasing doping concentrations ($x{\geq}0.3$). Electrical conductivity, Seebeck coefficient and power factor increased with the increasing amount of Ti contents. The lattice thermal conductivity decreased considerably, possibly due to the mass disorder and grain boundary scattering. All of these turned out to increase in power factor significantly. As a result, the thermoelectric figure of merit increased comprehensively with Ti doping for this experiment, resulting in maximum thermoelectric figure of merit for $FeV_{0.7}Ti_{0.3}Sb$ at 658 K.

Study on Design of Heavy Payload Robot Considering Design Factor of Gravity Compensator (중력보상장치 설계계수를 고려한 고가반 로봇설계에 관한 연구)

  • Lee, Do-Seung;Lee, Ho-Su;Pyo, Sang-Hun;Yoon, Jung-Won;Lyu, Sung-Ki
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.5
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    • pp.23-28
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    • 2019
  • In recent years, medium- to large-scale transportation machinery and machine tool manufacturing process lines have shown a trend toward centralization, softening, lightening, and slimming to reduce costs and increase productivity. This has increased the demand for vertical articulated robots. When developing and introducing a heavy weight-handling robot that can be easily applied to existing production lines, it is expected to have a great effect in securing industrial competitiveness by solving industrial issues such as the decreased productivity and increased risk of accidents due to work involving heavy lifting. In this study, we design a 6-axis robot mechanism with a heavy load-handling capacity of 700kg or more for large-sized materials of various types supplied in small quantities.

An Analysis of Grinding Effects and Economic Life of Cutting Tool with Proportional Age Reduction Model (비례 수명 감소 모형을 사용한 절삭공구의 연마효과 및 경제적 수명 분석)

  • Oh, Sung-Youl;Hong, Jung-Wan;Lee, Sang-Cheon;Lie, Chang-Hoon
    • IE interfaces
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    • v.19 no.4
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    • pp.316-323
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    • 2006
  • In this study, based on Weibull proportional age reduction model and age replacement policy, we analyze economic life of cutting tool which allows re-grinding. Re-grinding task, usually for high-priced machining tools(e.g., broaching tool), is a kind of preventive maintenance activities to extend tool life at the completion of a lot production. The numerical results are also presented. Among the parameters of Weibull proportional age reduction model, the re-grinding effect parameter and Weibull shape parameter have a strong effect on economic tool life, and in the cost parameters, shortage cost is most sensitive. With further study on the parameter estimation of tool life process and cost function, this study can be expected to give more practical contribution to management of general machining tools.

Automated Feature-Based Registration for Reverse Engineering of Human Models

  • Jun, Yong-Tae;Choi, Kui-Won
    • Journal of Mechanical Science and Technology
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    • v.19 no.12
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    • pp.2213-2223
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    • 2005
  • In order to reconstruct a full 3D human model in reverse engineering (RE), a 3D scanner needs to be placed arbitrarily around the target model to capture all part of the scanned surface. Then, acquired multiple scans must be registered and merged since each scanned data set taken from different position is just given in its own local co-ordinate system. The goal of the registration is to create a single model by aligning all individual scans. It usually consists of two sub-steps: rough and fine registration. The fine registration process can only be performed after an initial position is approximated through the rough registration. Hence an automated rough registration process is crucial to realize a completely automatic RE system. In this paper an automated rough registration method for aligning multiple scans of complex human face is presented. The proposed method automatically aligns the meshes of different scans with the information of features that are extracted from the estimated principal curvatures of triangular meshes of the human face. Then the roughly aligned scanned data sets are further precisely enhanced with a fine registration step with the recently popular Iterative Closest Point (ICP) algorithm. Some typical examples are presented and discussed to validate the proposed system.

Automatic Train Control (ATC) System Development through Application of Reverse and Re-Systems Engineering Process (역공학 및 재공학 시스템엔지니어링 프로세스 적용을 통한 무인열차자동제어시스템 개발)

  • 이중윤;박영원
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.10
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    • pp.836-843
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    • 2003
  • The automatic train control (ATC) system development project for the Automated Guideway Transit (AGT) system has high technical risk because the system is unmanned train control system using wireless technology which was unprecedented in train control industry of Korea. To overcome the technical risk during concept design phase of the ATC system development project, the integrated product team(IPT) carried out a reverse and reengineering process using a systems engineering design model. The generic systems engineering process is incorporated in the both reverse and reengineering process. As a result of the systems engineering effort, the IPT has built top layer systems engineering design model of the ATC subsystem. The purpose of this paper is to deliver the reverse and reengineering process which was used to develop the systems engineering design model of ATC system using a computer aided systems engineering tool. This study also shows that the model based reverse and reengineering process can reduce the technical risk by identifying the differences of requirement, functional and physical architecture between a reference system and a target system.