• Title/Summary/Keyword: Orthogonal Arrays

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Effective Process Parameters on Surface Roughness in Incremental Sheet Metal Forming (점진성형에서 표면거칠기에 영향을 미치는 공정 변수)

  • Lee, Sang-Yoon;Lee, Kyeong-Bu;Kang, Jae-Gwan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.6
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    • pp.66-72
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    • 2014
  • Incremental forming is a relatively novel sheet forming process, in which parts can be formed without the use of dedicated dies. In this paper, the influence of the process parameters (tool diameter, step size, feed rate, existence of a die, forming methods, and kinds of tool path) on surface roughness in the case in which parts are processed by incremental forming was discussed. Al 1050 material is used in the experiments. A table of orthogonal arrays is used to design the experiments and the ANOVA method is employed to statistically analyze the results. The obtained results show that the process parameters of tool diameter, step size, and the existence of a die have a significant effect on the surface roughness, whereas the feed rate, forming methods and kinds of tool path are insignificant.

Study on the Contribution Ratio of Factors to Affect Regeneration Performance of a Solar Air Conditioning System (태양열 이용 냉난방 공조시스템의 재생성능에 영향을 미치는 인자의 기여율에 관한 연구)

  • Kim, B.C.;Choi, K.H.;Kum, J.S.
    • Solar Energy
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    • v.20 no.1
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    • pp.91-96
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    • 2000
  • This study was performed to find out how much experimental factors influence on regeneration performance in a solar air conditioning system. The experimental apparatus was set up in a climate-controlled chamber where temperature and humidity could be kept constant. In order. to investigate factors' influence on the regeneration performance of the solar air conditioning system, the model experiment was done using the 600mm $\times$ 600mm black painted aluminum regenerator. The design and analysis of experiment were done by the design of experiments, especially the table of orthogonal arrays. In order to find out how much experimental factors influence on regeneration performance, the table of orthogonal arrays $L_8(2^7)$ was used. According to the results, it was found that the most influential factor to affect regeneration performance was the concentration of LiCl solution. The next influential factors were a solar radiation, an air velocity, and the temperature of LiCl solution in order.

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(Design of RFID Reader Antenna Using Two Orthogonally Oriented 1x2 Sub-Arrays at 433 MHz) (직교형으로 배열된 2개의 1x2서브-어레이를 이용한 433MHz에서 동작하는 RFID 리더용 안테나 설계)

  • Kim Jong-Sung;Park Seung-Mo;Choi Won-Kyu;Seong Nak-Seon
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.42 no.9 s.339
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    • pp.97-100
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    • 2005
  • An orthogonal antenna is presented for reader application of radio frequency identification (RFID) at 433 MHz. Two 1x2 sub-arrays are orthogonally placed on a ground plane and two different feeding networks are applied to control horizontal and vertical radiation current flows for each sub-array, respectively. Inverted-F structures are used as radiation elements and can generate two linear polarizations by relative current distribution of radiators forming sub-arrays. Antenna gains are 2.7 and 0.4 dBi and isolation between two input ports is less than 25dB.

Pareto Analysis of Experimental Data by L18(2 X 37) Orthogonal Array (L18(2 X 37) 직교배열표 실험자료에 대한 파레토 그림 분석)

  • 임용빈
    • The Korean Journal of Applied Statistics
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    • v.17 no.3
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    • pp.499-505
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    • 2004
  • The Pareto diagram analysis of the experimental data by the two level orthogonal arrays has been used widely in practice since it is a graphical, quick and easy method to analyze experimental results, which does not use the analysis of variance to screen significant effects. For the analysis of the experimental data by $L_{18}(2 \times 3^7)$ orthogonal array, Park(1996) proposed Pareto ANOVA in which the size of effects is defined by the mean squares of effects and the Pareto principle is used. In this paper, a new approach of the Pareto diagram analysis of the experimental data by $L_{18}(2 \times 3^7)$ orthogonal array is proposed. The main idea is to partition the size of three level effects by that of linear and quadratic orthogonal contrasts of those effects.

Space-Polarization Division Multiple Access System with Limited Feedback

  • Joung, Heejin;Jo, Han-Shin;Mun, Cheol;Yook, Jong-Gwan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.4
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    • pp.1292-1306
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    • 2014
  • This paper proposes a space-polarization division multiple access (SPDMA) system that has limited feedback channels. The system simultaneously serves data streams to multiple mobile users through dual-polarized antenna arrays, by using pre-determined sets of precoding vectors that are orthogonal in both space and polarization domains. To this end, a codebook whose elements are sets of the precoding vectors is systematically designed based on the discrete Fourier transform (DFT) matrix and considering the power imbalance of polarized channels. Throughput of the SPDMA system is evaluated and compared to that of space division multiple access (SDMA) system, according to the various parameters including cross polarization discrimination (XPD). The results show that the throughput of SPDMA system outperforms that of SDMA in the environments of high XPD with many mobile users.

Efficient detectors for MIMO-OFDM systems under spatial correlation antenna arrays

  • Guerra, David William Marques;Fukuda, Rafael Masashi;Kobayashi, Ricardo Tadashi;Abrao, Taufik
    • ETRI Journal
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    • v.40 no.5
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    • pp.570-581
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    • 2018
  • This work analyzes the performance of implementable detectors for the multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) technique under specific and realistic operation system conditions, including antenna correlation and array configuration. A time-domain channel model was used to evaluate the system performance under realistic communication channel and system scenarios, including different channel correlation, modulation order, and antenna array configurations. Several MIMO-OFDM detectors were analyzed for the purpose of achieving high performance combined with high capacity systems and manageable computational complexity. Numerical Monte Carlo simulations demonstrate the channel selectivity effect, while the impact of the number of antennas, adoption of linear against heuristic-based detection schemes, and the spatial correlation effect under linear and planar antenna arrays are analyzed in the MIMO-OFDM context.

Study of Deepsea Mining Robot "MineRo" Using Table of Orthogonal Arrays (직교 배열표를 이용한 심해저 채광로봇 미내로의 주행 특성 연구)

  • Lee, Chang-Ho;Kim, Hyung-Woo;Choi, Jong-Su;Yeu, Tae-Kyeong;Lee, Min-Uk;Oh, Jae-Won;Hong, Sup
    • Journal of Ocean Engineering and Technology
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    • v.28 no.2
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    • pp.152-159
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    • 2014
  • KRISO(Korea Research Institute of Ships & Ocean Engineering) designed and manufactured a pilot mining robot called "MineRo" in 2012. MineRo is composed of four track modules. In general, much time and money are needed for deep-sea tests. Therefore, a numerical analysis to predict the dynamic behaviors has to be performed before a deep-sea test. In the numerical analysis, the information about the mining robot and soil properties are the most important factors to analyze the driving performance and dynamic response of MineRo. A terra-mechanics model of extremely cohesive soft soil is implemented in the form of the relationships between the normal pressure and sinkage, and between the shear stress and shear displacement. It is possible to acquire information about MineRo from the CAD model in the design phase. The Wong model is applied to the terra-mechanics model. This model is necessary to acquire many soil coefficients for a numerical analysis. However, in soil testing, the amount of soil property data obtained is limited. Moreover, it is difficult to analyze all of the cases for the many soil coefficients. In this paper, the dynamic behaviors of MineRo are analyzed according to the driving velocity, steering ratio, and variable extremely cohesive soft soil properties using a table of orthogonal arrays. The dynamic responses of MineRo are the turning radius, sinkage, and slip ratio. The relationships between the dynamic responses and variable soil properties are derived for MineRo.

Adaptive beamforming for a PF-OFDM system using LMS algorithm (LMS기반 PF-OFDM엔서의 적응 빔포밍 설계)

  • Oh, Jun-Suk;Kim, Jae-Yun;Yoo, Kyung-Yul
    • Proceedings of the KIEE Conference
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    • 2005.07d
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    • pp.2998-3000
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    • 2005
  • The orthogonal frequency-division multiplexing (OFDM) technique is well known to be robust against the frequency-selective fading in wireless channels. It is due to the exploitation of a guard interval that is inserted at beginning of each OFDM symbol. Based or the conventional OFDM and a polyphase filtered orthogonal frequency division multiplexing (PF-OFDM) technique, we developed an adaptive beamforming algorithm for antenna arrays. The proposed algorithm would lead to an efficient use of channel, since it is possible to eliminate a guard interval and also easily suppress interchannel interference at the same time. In this paper, a series of computer simulations have been provided to show the performance of the proposed system.

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Optimization of Injection Molding Design Using Two-Characteristic Value Function Methodology (두 특성의 가치함수를 이용한 사출성형의 최적 설계)

  • Park, Jong-Cheon;Kim, Kyung-Mo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.14 no.1
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    • pp.36-43
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    • 2015
  • Optimizing multiple design characteristics which are usually in conflict with each other in the injection molding process is frequently becoming a critical problem for designers who work in this area. The purpose of this work is to develop an automated design methodology for optimizing two such design characteristics found in injection-molded parts. A value function based on decision-making theory is used as a means of evaluating the performance of a two-characteristic design alternative. Also, a design space reduction algorithm based on Taguchi's orthogonal arrays is utilized to discover an optimal design alternative. Verification of the developed design methodology is carried out for an actual model with two design characteristics, the weld line and the gate location, to be optimized in computer simulation experiments.

Improvement of Passenger Airbag Based on the Injury Assessment of the 5th Percentile Female Dummy (작은 체형의 여성 승객을 고려한 조수석 에어백의 설계 개선)

  • Kwon, Yul;Kim, Kwon-Hee;Son, Chang-Kyu;Kim, Hyung-Il
    • Transactions of the Korean Society of Automotive Engineers
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    • v.20 no.5
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    • pp.1-7
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    • 2012
  • Automobile airbag deployment process has been studied with MADYMO software. Based on the FMVSS208 and USNCAP(United States New Car Assessment Program) regulations, four parameters were chosen for the design improvement with reference to the 5th percentile female passenger dummy: time to fire, vent hole size, tether length and tank test pressure of inflator. Sensitivity analyses based on orthogonal arrays show that enhanced protection of small females can be achieved with improved USNCAP rating within the boundary of FMVSS 208.