• Title/Summary/Keyword: manufacturing lead time

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How to Implement 'Lean' Principles into Software Development Practice?: Visualization of Delays and Defects (린(Lean) 개념을 소프트웨어 개발 방법에 적용하기 위한 사례 연구: 낭비 제거의 가시화를 중심으로)

  • Hwang, Soon-Sam;Kim, Sung-K.
    • Information Systems Review
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    • v.13 no.1
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    • pp.61-74
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    • 2011
  • Software industry still has many deep-seated problems. As a natural consequence, it may have to learn from best practices in more mature industry like manufacturing. An example is 'lean' software development which is defined as translation of 'lean manufacturing' principles to the software development domain. The principles include 'eliminate waste' and 'amplify learning.' It was much asserted that these principles are worth applying. Not much study, however, was done on how to practically implement these principles into software development practice. In this study we attempt to present a method in which project lead time and software defects are regarded as major targets of management and are visualized using Cumulative Flow Diagram. We further applied this method on actual projects. The result confirms that agile is positively effective on reducing wastes.

Study on Rear Door Fixed Glass Weather-strip for Automobiles Using EPDM/Polypropylene Blend (I) (자동차용 Rear Door Fixed Glass Weather-strip 성형을 위한 EPDM과 Polypropylene의 Blend에 관한 연구 (I))

  • Park, Jong-Yun;Hwang, Sung-Hyuk;Kim, Jin-Kuk
    • Elastomers and Composites
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    • v.35 no.2
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    • pp.115-121
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    • 2000
  • In comparison with thermosetting rubber, thermoplastic elastomer (TPE) has various advantages such as simple processing, short cycle time and recycling of scrap. These advantages can lead to development of the high value-added rubber products due to reduction of the waste material, manufacturing cost and the defected product. This article involves a dynamic vulcanization method for EPDM/polypropylene blend, and the manufacturing of a fixed glass weather-strip by glass insert molding method using the blend. In order to investigate mechanical properties of the product, tensile strength, elongation, hardness and specific gravity were measured. Also morphological study was carried out using SEM. Developments of an efficient system of production and automatic process by molding of TPE and glass simultaneously are expected.

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Development of Intelligent ATP System Using Genetic Algorithm (유전 알고리듬을 적용한 지능형 ATP 시스템 개발)

  • Kim, Tai-Young
    • Journal of Intelligence and Information Systems
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    • v.16 no.4
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    • pp.131-145
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    • 2010
  • The framework for making a coordinated decision for large-scale facilities has become an important issue in supply chain(SC) management research. The competitive business environment requires companies to continuously search for the ways to achieve high efficiency and lower operational costs. In the areas of production/distribution planning, many researchers and practitioners have developedand evaluated the deterministic models to coordinate important and interrelated logistic decisions such as capacity management, inventory allocation, and vehicle routing. They initially have investigated the various process of SC separately and later become more interested in such problems encompassing the whole SC system. The accurate quotation of ATP(Available-To-Promise) plays a very important role in enhancing customer satisfaction and fill rate maximization. The complexity for intelligent manufacturing system, which includes all the linkages among procurement, production, and distribution, makes the accurate quotation of ATP be a quite difficult job. In addition to, many researchers assumed ATP model with integer time. However, in industry practices, integer times are very rare and the model developed using integer times is therefore approximating the real system. Various alternative models for an ATP system with time lags have been developed and evaluated. In most cases, these models have assumed that the time lags are integer multiples of a unit time grid. However, integer time lags are very rare in practices, and therefore models developed using integer time lags only approximate real systems. The differences occurring by this approximation frequently result in significant accuracy degradations. To introduce the ATP model with time lags, we first introduce the dynamic production function. Hackman and Leachman's dynamic production function in initiated research directly related to the topic of this paper. They propose a modeling framework for a system with non-integer time lags and show how to apply the framework to a variety of systems including continues time series, manufacturing resource planning and critical path method. Their formulation requires no additional variables or constraints and is capable of representing real world systems more accurately. Previously, to cope with non-integer time lags, they usually model a concerned system either by rounding lags to the nearest integers or by subdividing the time grid to make the lags become integer multiples of the grid. But each approach has a critical weakness: the first approach underestimates, potentially leading to infeasibilities or overestimates lead times, potentially resulting in excessive work-inprocesses. The second approach drastically inflates the problem size. We consider an optimized ATP system with non-integer time lag in supply chain management. We focus on a worldwide headquarter, distribution centers, and manufacturing facilities are globally networked. We develop a mixed integer programming(MIP) model for ATP process, which has the definition of required data flow. The illustrative ATP module shows the proposed system is largely affected inSCM. The system we are concerned is composed of a multiple production facility with multiple products, multiple distribution centers and multiple customers. For the system, we consider an ATP scheduling and capacity allocationproblem. In this study, we proposed the model for the ATP system in SCM using the dynamic production function considering the non-integer time lags. The model is developed under the framework suitable for the non-integer lags and, therefore, is more accurate than the models we usually encounter. We developed intelligent ATP System for this model using genetic algorithm. We focus on a capacitated production planning and capacity allocation problem, develop a mixed integer programming model, and propose an efficient heuristic procedure using an evolutionary system to solve it efficiently. This method makes it possible for the population to reach the approximate solution easily. Moreover, we designed and utilized a representation scheme that allows the proposed models to represent real variables. The proposed regeneration procedures, which evaluate each infeasible chromosome, makes the solutions converge to the optimum quickly.

Study on the Manufacturing Technology of Mural Tomb in Goa-dong of Daegaya Period (대가야 고아동 고분벽화 제작기술에 관한 연구)

  • Lee, Hwa Soo;Lee, Han Hyeong;Lee, Kyeong Min;Han, Kyeong Soon
    • Journal of Conservation Science
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    • v.30 no.4
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    • pp.457-466
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    • 2014
  • Rigorous analysis was performed to identify the structure and materials of the murals to study techniques used on mural tombs of ancient Daegaya era(6th century). The murals were painted by applying mortar on the walls and the ceiling after building a stone chamber and creating ground layers on mortar layers. Mud was applied on most of the mortar layers on four sides of the walls except the ceiling. Sand was not used in mortar but was made of materials with pure calcium substances. In addition, shells in irregular sizes with incomplete calcination were mixed; and the mortar's white powder was inferred as lime obtained by calcination of oyster shells. Kaolinite($Al_2Si_2O_5(OH)_4$) was used in the ground layer, Cinnabar(HgS) was used for red pigment, Malachite($Cu_2CO_3(OH)_2$) for green and Lead white($PbCO_3{\cdot}Pb(OH)_2$) for white. Mud plaster was applied on the mortar and was composed thinly and densely using clayey of particle size smaller than that of medium sand. It was assumed that the finishing was for repair after long time had passed since the mortar layer came off. Using lime made with oyster shells as mortar is unprecedented in ancient Korean mural tombs and its durability was very poor, suggesting that Gaya's mortar production technique was relatively behind compared to that of Koguryo's in the same era.

Flexible Roll Forming Technology for Multi-Curved Sheet Metal Forming (다중곡률형상의 판재성형을 위한 가변롤성형 기술)

  • Yoon, J.S.;Son, S.E.;Song, W.J.;Kim, J.;Kang, B.S.
    • Transactions of Materials Processing
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    • v.22 no.5
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    • pp.243-249
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    • 2013
  • The multi-point forming (MPF) process for three-dimensional curved sheet metal has been developed as an alternative to the conventional die forming process since MPF allows the manufacturing of various shapes using one die set and reduce the cost of production. However, the MPF process cannot provide high quality products yet due to defects occurring in the sheet such as dimples and wrinkles. It can also lead to economic loss because of long tool setup time and additional machining required outside of the sheet formed area. In this study, a new sheet metal forming method, called flexible roll forming (FRF), is proposed to solve the problems of existing processes for three-dimensional curved sheet metal. This progressive process utilizes adjusting rods, as well as upper and lower flexible rollers as forming tools. In contrast with the existing processes, FRF can reduce the additional production costs because of the possible blank size for the part longitudinal direction, which is unrestricted. In this research, methods and procedures of the flexible roll forming technology are described. Numerical forming simulations of representative three-dimensional curved sheet products are also carried out to demonstrate the feasibility of this technology.

The study on the construction of IWSDB for National Defense CALS (국방 CALS를 위한 IWSDB 구축에 관한 연구)

  • 신선우;손해용;김철환
    • The Journal of Society for e-Business Studies
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    • v.1 no.1
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    • pp.93-116
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    • 1996
  • This study aims to develop an approach to construct IWSDB for National Defense CALS. Along with the introduction of Korean version of CALS conception, it is essential to analyze the national defense system with a new information technology for the construction of IWSDB. A long-tenn goal of CALS is to construct fully Integrated Data Environment (IDE) and establish IWSDB for the application of CALS conception to the life cycle management of weapon system. IWSDB is a set of databases that contain digital data. It supports common interface of data objects and databases throughout the life cycle management of weapon system, including design, engineering, analysis, manufacturing, operation, and logistics. etc. The goal of this study is threefold. First, we propose a right direction for the establishment of Integrated Data Environment. For the integrated database technology, we use the five schema architecture and the distributed object oriented technology that will lead to the "share of data." Second, we present the most effective IWSDB architecture for defense CALS, which will provide the efficient data sharing by business process modeling. Third, we suggest that IWSDB should be constructed based on the process which is related to the acquisition and logistics of weapon system for the national defense, and at the same time it should be implemented with GITIS for government agencies and CITIS for the industries in order to obtain the efficient data sharing.

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A study on pcb lead time reduction with the automatic start of environment designing cad allegro (CAD Allegro을 이용한 환경 자동실행으로 PCB작업시간 단축에 대한 연구)

  • Lee, Sang-Ho;Kim, Young-Gil
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.6
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    • pp.1204-1208
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    • 2012
  • According to the rapid development of cell phone and camera industry, all of electronic products obtain small-size, high-performance and variety. Therefore, PCB also obtains high-integration, multi-layers and high-specification rapidly. Among the digital cameras which are continuously evolved and developed, the market of mirror-less camera and hybrid digital camera is continuously increased because of the customer's request for small-size and weight lightening, except for DSLR camera. Therefore, the difficulty of PCB design is gradually increased and design L/T is longer according to the high-specifications, low-current and high-performance components. This thesis suggests the method to reduce L/T for PCB design applied to the reduction of digital camera's developing period and manufacturing period.

Moisture Absorption Properties of Organic-Inorganic Nano Composites According to the Change of Epoxy Resins for Next Generation Semiconductor Packaging Materials (차세대 반도체용 유-무기 나노 복합재료의 에폭시 수지변화에 따른 흡습특성)

  • Kim, Whan Gun;Kim, Dong Min
    • Journal of the Semiconductor & Display Technology
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    • v.12 no.1
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    • pp.23-28
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    • 2013
  • Epoxy resins are widely used in microelectronics packaging such as printed circuit board and encapsulating for semiconductor manufacturing. Water can diffuse into and through the epoxy matrix systems and moisture absorption at boarding interfaces of matrix resin systems can lead to a hydrolysis at the interfaces resulting in delamination of encapsulating materials. In the study, the changes of diffusion coefficient and moisture content ratio of epoxy resin systems with nano-sized fillers according to the change of liquid type epoxy resins were investigated. RE-304S, RE-310S, RE-810NM and HP-4032D as a epoxy resin, Kayahard AA as a hardener, and 1B2MI as a catalyst were used in these epoxy resin systems. After curing, moisture content ratios were measured with time under the 85 and 85% relative humidity condition using a thermo-hydrostat. The maximum moisture absorption ratio and diffusion coefficient of EMC decrease with the filler content. It can be seen that these decreases are due to the increase of filler surface area and the decrease of moisture through channel with the content of nano-sized filler.

The Structure and Job Analysis of Apparel Buying Office in Korea

  • Chun, Jong-Suk;Yi, Yoo-Jin
    • The International Journal of Costume Culture
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    • v.12 no.2
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    • pp.141-152
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    • 2009
  • In this study, the business structure and characteristics of buying offices used by buyers for apparel productions through global sourcing were analyzed in specifics. Data were acquired through in-depth interviews of twelve merchandisers at representative apparel buying offices. The results of this study can be summarized as following. The business structure of a buying office varied depending on the functions, the item characteristics of products to be manufactured or the characteristics of the major buyers who were the customers. Overall, teams were formed by brands or organizations were formed by functions. Functional teams were divided within each brand team when business teams were divided by brands and personnel was divided by brands occasionally within each functional team when business teams were divided by functions. Business teams were composed of MR which managed the overall business about orders such as factory sourcing, price decision and production management and teams with various specialized skills. The teams with specialized skills were composed of Technical team, Fabric Development team, Colorist team, Quality Assurance (QA) or Quality Control (QC) team, Logistics team, Factory Audit team, and etc. For the future directions on the improvements, ways to increase international competitiveness of buying offices need to be researched and many expressed the opinion that it would be effective to move the offices to countries close to buyers or manufacturing locations as most buyers demand lower prices and shorter lead time than before and it is increasing trend for buyers and factories to do business directly without buying offices in the middle.

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Computer Simulation and Control performance evaluation of Ultra Precision Positioning Apparatus using Piezo Actuator (Piezo Actuator를 이용한 초정밀 위치결정기구의 Computer Simulation 및 제어 성능평가)

  • 김재열;김영석;곽이구;한재호
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.118-122
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    • 2000
  • Recently, High accuracy and precision are required in various industrial field especially, semiconductor manufacturing apparatus, Ultra precision positioning apparatus, Information field and so on. Positioning technology is a very important one among them. For composition of this technology, the development of system with high speed and high resolution is needed. At start point and end position vibration must be repressed on this system for composition of position control. This vibration is arisen nose, is increased setting time, is reduced accuracy. Especially, repressed for the lead with high speed. The small actuator with high speed and high resolution is need to repression against this residual vibration. This actuator is, for example, piezo actuator, piezoelectric material that converting from electronic signal to mechanical force is adequate material, beacause of control of control to position and force. In this study, piezo electric material is used to actuator, ultra precision positioning apparatus with stage of hinge structure is designed, simulation is performed, control performance is tested by producing apparatus. For easy usage and stability in industrial field, we perform to simulation and to position control test by digital PID controller.

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