• Journal of Industrial Technology
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• v.31 no.A
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• pp.45-51
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• 2011

A study has been made on defects which are formed in manufacturing processes of engine bearing and also on fatigue crack growth behavior in each step of bearing metal manufacturing. After the first step (sinter brass powder on steel plate ; Series A) many voids are made on brass surface and its size is decreased at the second step (rolling process of sintered plate ; Series B). After the third step (re-sintering step of brass powder and rolling ; Series C) the number of voids is decreased and its type shows line. The time of fatigue crack initiation and the growth rate of fatigue crack are in order of Series A, Series B, Series C. These reasons are that void fosters the crack initiation and growth, and residual stress made by rolling process affects on the crack growth rate in Series B, C. In forming and machining processes by use of final bearing metal, crack was observed at internal corner of flange and peeling off was observed at interface between steel and brass. Owing to the above crack and peeling off, it is considered that there is a possibility of fatigue fracture during the application time.

• Structural Engineering and Mechanics
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• v.86 no.1
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• pp.93-107
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• 2023

In this paper, a density based topology optimization is proposed for generating of supports required in additive manufacturing to maintain the overhanging regions of main structures during layer by layer fabrication process. For this purpose, isogeometric analysis method is employed to model geometry and structural analysis of main and support structures. In order to model the problem two cases are investigated. In the first case, design domain of supports can easily be separated from the main structure by using distinct isogeometric patches. The second case happens when the main structure itself is optimized by using topology optimization and the supports should be designed in the voids of optimum layout. In this case, in order to avoid boundary identification and re-meshing process for separating design domain of supports from main structure, a parameterization technique is proposed to identify the design domain of supports. To achieve this, two density functions are defined over the entire domain to describe the main structure and supporting areas. On the other hand, since supports are under gravity loads while main structure and its stiffness is not completed during manufacturing process, in the proposed method, stiffness of the main structure is considered to be trivial and the gravity loads are also naturally applied to design support structures. By doing so, the results show reasonable supports are created to protect, continuously, overhanging surfaces of the main structure. Several examples are presented to demonstrate the efficiency of the proposed method and compare the results with literature.

• 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.

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.3
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• pp.59-63
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• 2008

A static load analysis of twin-screw kneaders is required not only for the dynamic analysis, but also because it is the basis of the stiffness and strength calculations that are essential for the design of bearings. In this paper, the static loads of twin-screw kneaders are analyzed, and a mathematical model of the force and torque moments is presented using a numerical integration method based on differential geometry theory. The calculations of the force and torque moments of the twin-screw kneader are given. The results show that the $M_x$ and $M_y$ components of the fluid resistance torque of the rotors change periodically in each rotation cycle, but the $M_z$ component remains constant. The axis forces $F_z$ in the female and male rotors are also constant. The static load calculated by the proposed method tends to be conservative compared to traditional methods. The proposed method not only meets the static load analysis requirements for twin-screw kneaders, but can also be used as a static load analysis method for screw pumps and screw compressors.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.26-31
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• 2005

In national prospective, the needs to develop water resources has been increased due to water shortage from diverse use of water resources in agricultural areas. Existing agricultural water demand, which has mainly been limited to the use of farming, are now expanding to diverse water uses such as supporting daily lives, diluting environmental pollution as well as industrial use for agricultural complex currently under construction in agricultural region. In this situation, for the sake of effective procurement of water resources and supply method, it is definitely required to enhance the effectiveness of budget investment and project proceedings through integrated re-development which links projects to strengthen existing dams, reservoirs and hydraulic facilities. The major scopes of this research includes developing different types of system such as selecting potential sites to re-construct reservoirs including generating base maps and thematic maps, data collection regarding water demands and reservoir status; analyzing reservoir data; estimating developable capacity and index calculation; and forecasting inundated areas. In addition, this study provides other products such as developing output generation system which can support wide use of data built and analyzed; database generation for better data management; data analysis including selection, extraction, indexation, and calculation of base items through standardization; data security system prohibiting exterior proliferation and malicious manufacturing of data.

• Journal of Industrial Technology
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• v.36
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• pp.23-31
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• 2016

This paper presents EMQ models in which some proportion of defective items are produced and some of them are converted to good items through rework process and items not converted are disposed. Numerical models are developed for three cases of disposal and optimal solution of each model is derived. In the first model, if a defective item is found during the production process, only re-workable items are stored and reworked after normal production is finished. Not re-workable items are disposed immediately during normal production. The second model deals with the case where all defective items are stored and items to be disposed are determined in rework process. In the third model, an additional inspection process exists before rework to determine rework or disposal. Numerical examples are presented to validate the proposed models.

• The Journal of Society for e-Business Studies
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• v.1 no.1
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• pp.227-247
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• 1996

Presented in this paper is a control model for developing virtual factory simulator, which is being operated under the distributed environment. The control model consists of production activity plan and information flows. To incorporate elements of the characteristics of the distributed control system, we suggested a collaboration model. This model is working under the client/server architecture, and also designed for cooperative-distributed shop control(CDSC) system in order to exploit several advantages of client/server architecture. Collaboration among each agent(or client) is done through negotiation and task sharing. Based on a contract net model, the CDSC system has three kinds of agents-order agent, resource agent, and communication forwarding agent. Each agent performs shop scheduling and control through negotiation on contract net. No node in CDSC system can have authority over other node. A bidding scheme is employed far negotiation between order agent and resource agents. The CDSC system can support re-negotiation among resource agents and an algorithm for re-negotiation is also developed. Experimental results are shown to advocate the effectiveness of the CDSC system for CIM environments.

• Design & Manufacturing
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• v.16 no.3
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• pp.34-38
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• 2022

Regular expression pattern matching is widely used in applications such as computer virus vaccine, NIDS and DNA sequencing analysis. Hardware-based pattern matching is used when high-performance processing is required due to time constraints. ReCPU, SMPU, and REMP, which are processor-based regular expression matching processors, have been proposed to solve the problem of the hardware-based method that requires resynthesis whenever a pattern is updated. However, these processor-based regular expression matching processors inefficiently handle repetitive operations of regular expressions. In this paper, we propose a new instruction set to improve the inefficient repetitive operations of ReCPU and SMPU. We propose REMPi, a regular expression matching processor that enables efficient iterative operations based on the REMP instruction set. REMPi improves the inefficient method of processing a particularly short sub-pattern as a repeat operation OR, and enables processing with a single instruction. In addition, by using a down counter and a counter stack, nested iterative operations are also efficiently processed. REMPi was described with Verilog and synthesized on Intel Stratix IV FPGA.

• The International Journal of Costume Culture
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• v.4 no.2
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• pp.124-137
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• 2001

The digitalization of the fashion industry refers to 'the reception of the digital environment by the industry.'Re paper presented 3 conceptual categories of 'technological environment','information environment'and 'business environment'concerning the scope of digitalization, including from the introduction and use of new technical media to new ways of thinking following the paradigm changes. And it demonstratively analyzed digitalization factors and digitalization level of fashion businesses related to the factors by 7 fashion categories. The analytic result and its suggestions are as follows. First, the five digitalization factor of the fashion industry are defined : manufacturing Process automation, computer systemization, information networking, e-business, and small batch production. Second the digitalization degree of fashion firms decreases in the order of information networking, small batch Production, manufacturing Process automation, computer systemization, and e-business, with information networking on the top and e-business, recent focal point of interest, at the bottom. Third, as for the digitalization of each clothing category, men's formal dress and unisex display the highest level of the general digitalization.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.3
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• pp.19-27
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• 2011

A weaving machine for texture industry uses a lot of needles and the nib of these needles is necessary to be kept with sharp edge. The re-grinding of the needle by a special purpose of the grinding wheel can be selected for achieving this aim. This study focused on the manufacture and performance assessment the special grinding wheel. A forming mold for the grinding wheel was designed and a sintering process for furnace process control was established. Manufactured wheels were tested for determining suitable grade of the wheel. The selection of optimal grinding conditions was achieved by a response surface method and a genetic algorithm.