• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.410-413
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• 2003

In order to build up competitive power in construction market and to cope with international policy, Design-Build bidding is one of the viable bidding system, encouraging collaboration between design office and building construction firm. Design-Build is a promising delivery system to help expediting schedules, saving costs, and improving Quality. However, the problems of Design-Build project in the domestic construction industry are not to be able to take advantages of fast-tracking and value engineering process, because of the problems of inappropriate system and participants' inexperience. The purpose of this study is to suggest alternatives for Design-Build bidding of public sector in the domestic construction industry in the costs, quality and time aspect.

• Korean Journal of Construction Engineering and Management
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• v.6 no.4 s.26
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• pp.91-100
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• 2005

Design-build that a single entity performs whole construction process under singular responsibility is one of the project delivery system comes to take expectation effects of time savings, cost saving, and quality assurance. On the other hand, a current domestic method for selecting a design-build contractor is difficult to reflect the purpose of owner and the project characteristics when owner selects the design-build contractor. The purpose of this research is to suggest a model for deciding evaluation weights in design-build which can reflect the purpose of owner and the project characteristics. This research can help owner to select the best suitable design-build contractor for the project.

• Journal of The Korean Digital Architecture Interior Association
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• v.8 no.2
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• pp.65-72
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• 2008

Therefore about the city research the research will be necessary from historical time. Are not adapted to a finally new situation the functions atrophy and they change, the different city function creating, they do. Specially, the time according to becoming, becomes the axial oneself more city intensive painter, or, in the city which extends the territory, compares the process which is special historically and the change which change etc. is various is rough (Japanese colonial time) with the atrophy which illustrates shows From the research which sees consequently (1) The background which the central area of the city comes to build and tries to analyze the features which changes from the cities and social viewpoints. And (2) Tries to investigate the city system which comes to make from the process which is special is a Japanese colonial time, Also (3) About movement of the process which the city central area which happens from that place comes to build and the city central area searches. With being like that, Space Syntax where uses from the research which sees makes the result which leads with objective the ground and the reporter comparison to analyze with social causes together does.

• Journal of Construction Engineering and Project Management
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• v.6 no.2
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• pp.16-23
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• 2016

The use of inappropriate procurement methods to deliver construction projects has long been acknowledged as a major source of poor project performance and is particularly problematic for the Libyan Construction Industry. Poor procurement method selection has been recognised as a major contributory factor to frequent time and cost overruns. This paper offers a way of selecting specific procurement methods to maximize successful project performance. The methodology involves an intensive review of relevant literature, followed by a semi-structured questionnaire survey. The key findings of the study reveal that 11 out of its 12 common selection criteria exhibit a significant contribution to one or more project performance criteria (time, cost and quality). Project clients should therefore prioritise these criteria when selecting a design-bid-build method. Knowledge of the criteria that contribute positively to project performance will also enable clients to work out, prior to and during construction, the best measures and provisions for successful project outcomes.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.11
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• pp.139-147
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• 1999

Rapid Prototyping has made a drastic change in all industries which needs to reduce the time for the development of new products. Orientation and packing in rapid prototyping is considered as the most important factors to maximize the utilization of space in the build chamber and reduce build time. However, the decision of these parameter is mainly dependant on the operators's experience. This paper presents the methodology to find the optimal build layout considering an orientation and packing of multiple parts in SLS processing. Each part is represented as a voxel structure to deal with the inefficiency in a bounding box approach. Test results show that the adapted BL algorithm with a genetic algorithm(GA) can be applicable to a real industry.

• Korean Journal of Computational Design and Engineering
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• v.11 no.3
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• pp.223-233
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• 2006

Layered manufacturing(LM) is emerging as a new technology that enables the fabrication of three dimensional heterogeneous objects such as Multi-materials and Functionally Gradient Materials (FGMs). Among various types of heterogeneous objects, more attention has recently paid on the fabrication of FGMs because of their potentials in engineering applications. The necessary steps for LM fabrication of FGMs include representation and process planning of material information inside an FGM. This paper introduces a new process planning algorithm that takes into account the processing of material information. The detailed tasks are discretization (i.e., decomposition-based approximation of volume fraction), orientation (build direction selection), and adaptive slicing of heterogeneous objects. In particular, this paper focuses on the discretization process that converts all of the material information inside an FGM into material features like geometric features. It is thus possible to choose an optimal build direction among various pre-selected ones by approximately estimating build time. This is because total build time depends on the complexity of features. This discretization process also allows adaptive slicing of heterogeneous objects to minimize surface finish and material composition error. In addition, tool path planning can be simplified into fill pattern generation. Specific examples are shown to illustrate the overall procedure.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.2
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• pp.154-161
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• 1998

Prototypes of a design are always needed for the purpose of visualization and evaluation in the aspect of manufacturability functionality, and aesthetic appearance. Since the prototyping process requires a significant amount of cost and time, various rapid prototyping processes are recently being introduced in the process. However, it is usually necessary for a part built up by a rapid prototyping system to be refined by a post-processing process, in which the stair steps on the surfaces, the support structures (if they exist), and the unprocessed material are eliminated. This post-processing is usually done manually and is a time-consuming task. Especially, eliminating the trapped volumes, the volume of the unprocessed material entrapped by the solidified portion, is sometimes impossible in some processes. This study provides a designer with a tool to detect the existence and to calculate the quantity of the trapped volumes at the given build-up direction, so that the proper build-up direction is chosen or the part is built by pieces to avoid the problems caused by the trapped volumes in advance. Since the proposed algorithm can efficiently calculate the amount of the trapped volumes at any build-up direction, it has the potential of such application as optimizing the build-up direction to minimize the trapped volumes.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.96-102
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• 2005

The tribocharge build-up in the slider disk interface can cause ESD (electrostatic discharge) damage. In turn, ESD can cause severe melting damage to MR or GMR heads. We investigated the tribovoltage/current build-up with smooth and textured disks in HDD, operating at increasing disk accelerations. We found that tribe-voltage/current were generated during pico-slider/disk interaction and those levels were about 0.1 ${\~}$ 0.3 V and 10 ${\~}$ 40 pA, respectively. Tribovoltage/current were abruptly increased and dissipated within the acceleration time in the case of textured disk but in the case of smooth disk tribovoltage was continuously increased until the end of uniform velocity region and the tribocurrent did not dissipate within the acceleration time. In the case of textured dist tribovoltage/current was reduced with increasing disk acceleration, but in the case of smooth disk it was increased.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04a
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• pp.552-558
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• 1995

Stereolithography is a process used to rapidly produce polymer components directly from a computer-representation of the part. There are several considerations to be made for the efficient use of te process. Especially, the build-up orientation of part critically affect to the part accuracy, total build time and the volume of support structures. Te purpose of this study is to determine the optimal build-up part orientation for the SLA process with improving part accuracy, minimizing total build time, and the volume of supprot structures. The first factor is related to the area of surfaces which have staircase protrusions after solidification, the second factor is related to the total number of layers, and the third factor is related to the area of the surfaces which need to be supported with support structures. An algorithm is developed to calculate the staircase area with quantifying the process planning errors that the volume of materials is supposed to be removed or added to the part, and the optimal layer thickness for the SLA system whichcan hadle the variable layer thickness in different orientations achieved by rotating the given part to the specified finite directions. So the optimal part orientation is determined based on the user's selections of primary criterion and the optimal thickness of layers is calculated at any part orientations.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.4
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• pp.51-56
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• 2003

Generally, the build-up printed circuit board manufactured by a sequential process involving etching, plating, drilling, etc, which requires many types of equipments and long lead time. Etching process is suitable for mass production, however, it is not adequate for manufacturing a prototype in the development stage. In this study, we introduce a screen printing technology for prototyping a build-up printed circuit board. As for the material, photo/thermal curable resin and conductive paste are used for the formation of dielectric and conductor. The build-up structure is made by subsequent processes such as formation of a liquid resin thin layer, solidification by a UV/IR light, and via hole filling with a conductive paste. By use of photo curable resin, productivity is greatly enhanced compared with thermal curable resin. Finally, the basic concept and the possibility of build-up printed circuit board prototyping are proposed in comparison with the conventional process.