• Title/Summary/Keyword: optimal processing

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An Efficient Algorithm for a Block Angular Linear Program with the Same Blocks (부분문제가 같은 블록대각형 선형계획문제의 효율적인 방볍)

  • 양병학;박순달
    • Journal of the Korean Operations Research and Management Science Society
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    • v.12 no.2
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    • pp.42-50
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    • 1987
  • This objective of this paper is to develop an efficient method with small memory requirement for a feed-mixing problem on a micro computer. First this method uses the decomposition principle to reduce the memory requirement. Next, the decomposition principle is modified to fit the problem. Further four different variations in solving subproblems are designed in order to improve efficiency of the principle. According to the test with respect to the processing time, the best variation is such that the dual simplex method is used, and the optimal basis of a previous subproblem is used as an initial basis, and the master problem is (M +1) dimensional. In general, the convergence of solution becomes slower near the optimal value. This paper introduces a termination criterion for a sufficiently good solution. According to the test, 5%-tolerence is acceptable with respect to the relation between the processing time and optimal value.

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A numerical study on micro leakage behaviors at cavity edge during photo reaction injection molding (광반응사출성형 시 캐비티 엣지에서 발생하는 미세누출현상에 관한 해석적 연구)

  • La, Moon-woo
    • Design & Manufacturing
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    • v.10 no.3
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    • pp.8-13
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    • 2016
  • Despite technological advance, there have been several troubles in photo reaction injection molding (photo RIM) to produce ultra thin light guide panels (LGPs). In this study, micro leakage problem at cavity edge during photo RIM was investigated numerically. In order to obtain optimal processing conditions, we regulated inlet pressure of injected resin at the cavity edge and figured out micro leakage behaviors. At low inlet pressure (less than 100 Pa), though the micro leakage problem was not occurred, another problem, short shot due to not enough driving force, was appeared More than 1,000 Pa of the inlet pressure, injected resin was rapidly leaked through the micro gap at the cavity edge. Finally, we obtained optimal inlet pressure around 600 ~ 1,000 Pa. At this region, injected resin fully filled the cavity without micro leakage behavior. Based on the present study, further comparative investigations with experimental photo RIM should be performed to find optimal processing conditions for produce ultra thin LGPs.

Searching Optimal Cutting Condition for Surface Roughness In Turning Operation on Inconel 718 using Taguchi Method (다구찌 방법을 이용한 Inconel 718 소재의 선삭가공에서 표면거칠기 최적화)

  • Cha, Jin-Hoon;Han, Sang-Bo
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.19 no.2
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    • pp.295-300
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    • 2010
  • Inconel 718 alloy, widely used as material of aircraft engine, has a good mechanical property in high temperature, strong anti-oxidation characteristics in oxidated current over $900^{\circ}C$, and also is not easily digested in the air containing sulfur, therefore, its usage as mechanical component is expanding rapidly. Even though Inconel alloy 718 is difficult to machine, it requires highly precise processing/machining to sustain its component quality of high accuracy. In this paper, general turning operation conditions arc tested to select the best cutting process condition by measuring surface roughness through implementing experiments with orthogonal array of cutting speed, feeding speed and cutting depth as processing parameters based on the Taguchi method. Optimal turning operation conditions are extracted from the proposed experimental models.

Optimal Cutting Conditions of Surface Roughness for Inconel 718 Alloy in Turning Operation (선삭가공시의 인코넬 718합금의 표면거칠기 최적 절삭조건)

  • Park, Jong-Min;Choi, Won-Sik;Kwon, Soon-hong;Cha, Jinhoon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.8 no.4
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    • pp.48-53
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    • 2009
  • Inconel 718 alloy, widely used as material of aircraft engine, has a good mechanical property in high temperature, strong anti-oxidation characteristics in oxidated current over $900^{\circ}C$, and also is not easily digested in the air containing sulfur, therefore, its usage as mechanical component is expanding rapidly. Even though Inconel alloy 718 is difficult to machine, it requires highly precise processing/machining to sustain its component quality of high accuracy. In this paper, general turning operation conditions are tested to select the best cutting process condition by measuring surface roughness through implementing experiments with orthogonal array of cutting speed, feeding speed and cutting depth as processing parameters based on the Taguchi method. Optimal turning operation conditions are extracted from the proposed experimental models.

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Optimal Datum Unit Definition for Diagnostics of Journal Bearing System (저널베어링 상태 진단을 위한 최적의 데이터 분석 기준 설정)

  • Youn, Byeng D.;Jung, Joonha;Jeon, Byungchul;Kim, Yeon-Whan;Bae, Yong-Chae
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.84-89
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    • 2014
  • Data-driven method for fault diagnostics system often use machine learning technique. To use such technique proper signal processing should be implemented such as time synchronous averaging (TSA) for ball bearing systems. However, for journal bearing diagnostics systems not much has been researched, and yet a proper signal processing method has not been studied. Therefore, in this research an optimal datum unit for a reliable journal bearing diagnostics system along with angular resampling process is being suggested. Before extracting time and frequency domain features, angular resampling is applied to each cycle of vibration data. As to preserve the characteristics of vibration signal, averaging method is replaced by finding the optimal datum unit which strengthens statistical characteristics of vibration signal. Then 20 features were extracted for various cases, and those features are being evaluated by two criteria, separability and classification accuracy.

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A Study on the File Allocation in Distributed Computer Systems (분산 컴퓨터 시스템에서 파일 할당에 관한 연구)

  • 홍진표;임재택
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.27 no.4
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    • pp.571-579
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    • 1990
  • A dynamic relocation algorithm for non-deterministic process graph in distributed computer systems is proposed. A method is represented for determining the optimal policy for processing a process tree. A general database query request is modelled by a process tree which represent a set of subprocesses together with their precedence relationship. The process allocation model is based on operating cost which is a function fo selection of site for processing operation, data reduction function and file size. By using expected values of parameters for non-deterministic process tree, the process graph and optimal policy that yield minimum operating cost are determined. As process is relocated according to threshold value and new information of parameters after the execution of low level process for non-deterministic process graph, the assigned state that approximate to optiaml solution is obtained. The proposed algorihtm is heuristic By performing algorithm for sample problems, it is shown that the proposed algorithm is good in obtaining optimal solution.

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Contact oxide etching using $CHF_3/CF_4$ ($CHF_3/CF_4$를 사용한 콘택 산화막 식각)

  • 김창일;김태형;장의구
    • Electrical & Electronic Materials
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    • v.8 no.6
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    • pp.774-779
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    • 1995
  • Process optimization experiments based on the Taguchi method were performed in order to set up the optimal process conditions for the contact oxide etching process module which was built in order to be attached to the cluster system of multi-processing purpose. In order to compare with Taguchi method, the contact oxide etching process carried out with different process parameters(CHF$_{3}$/CF$_{4}$ gas flow rate, chamber pressure, RF power and magnetic field intensity). Optimal etching characteristics were evaluated in terms of etch rate, selectivity, uniformity and etched profile. In this paper, as a final analysis of experimental results the optimal etching characteristics were obtained at the process conditions of CHF3/CF4 gas flow rate = 72/8 sccm, chamber pressure = 50 mTorr, RF power = 500 watts, and magnetic field intensity = 90 gauss.

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Optimal Release Time of Switching Software and Evolution of Reliability Based on Reliability Indicator (신뢰성 평가척도를 중심으로 한 교환 소프트웨어 최적 배포 시기 결정 및 신뢰도 평가)

  • Lee, Jae-Gi;Sin, Sang-Gwon;Hong, Seong-Baek
    • The Transactions of the Korea Information Processing Society
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    • v.6 no.3
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    • pp.615-621
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    • 1999
  • On the aspect of on-time and development resource use, it is very important to predict the software release time during the software development process. In this paper, we present the optimal release problem based on the evaluation indicator and cost evaluation. And also we show the optimal release point considered with both of them. We applied the Exponential Software Reliability Growth Model(E-SRGM) and Testing-effort dependent Software Reliability Growth Model(Te-SRGM) and decided the software release time according to software reliability indicator. As a result of two models comparison, we verify the Te-SRGM is more adopted in our switching system software.

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Non-iterative Bit Loading Algorithm for OFDM in Independent and Correlated fading

  • Manry, John W.;Nagaraj, Santosh
    • Journal of Information Processing Systems
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    • v.10 no.2
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    • pp.163-175
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    • 2014
  • This paper will focus on improving the performance of orthogonal frequency division multiplexing (OFDM) in Rayleigh fading environments. The proposed technique will use a previously published method that has been shown to improve OFDM performance in independent fading, based on ordered sub-carrier selection. Then, a simple non-iterative method for finding the optimal bit-loading allocation was proposed. It was also based on ordered sub-carrier selection. We compared both of these algorithms to an optimal bit-loading solution to determine their effectiveness in a correlated fading environment. The correlated fading was simulated using the JTC channel models. Our intent was not to create an optimal solution, but to create a low complexity solution that can be used in a wireless environment in which the channel conditions change rapidly and that require a simple algorithm for fast bit loading.

Secure Performance Analysis Based on Maximum Capacity

  • Zheng, Xiuping;Li, Meiling;Yang, Xiaoxia
    • Journal of Information Processing Systems
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    • v.16 no.6
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    • pp.1261-1270
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    • 2020
  • The physical security layer of industrial wireless sensor networks in the event of an eavesdropping attack has been investigated in this paper. An optimal sensor selection scheme based on the maximum channel capacity is proposed for transmission environments that experience Nakagami fading. Comparing the intercept probabilities of the traditional round robin (TRR) and optimal sensor selection schemes, the system secure performance is analyzed. Simulation results show that the change in the number of sensors and the eavesdropping ratio affect the convergence rate of the intercept probability. Additionally, the proposed optimal selection scheme has a faster convergence rate compared to the TRR scheduling scheme for the same eavesdropping ratio and number of sensors. This observation is also valid when the Nakagami channel is simplified to a Rayleigh channel.