• 제목/요약/키워드: engineering technique

검색결과 22,315건 처리시간 0.045초

Discretization technique for stability analysis of complex slopes

  • Hou, Chaoqun;Zhang, Tingting;Sun, Zhibin;Dias, Daniel;Li, Jianfei
    • Geomechanics and Engineering
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    • 제17권3호
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    • pp.227-236
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    • 2019
  • In practice, the natural slopes are frequently with soils of spatial properties and irregular features. The traditional limit analysis method meets an inherent difficulty to deal with the stability problem for such slopes due to the normal condition in the associated flow rule. To overcome the problem, a novel technique based on the upper bound limit analysis, which is called the discretization technique, is employed for the stability evaluation of complex slopes. In this paper, the discretization mechanism for complex slopes was presented, and the safety factors of several examples were calculated. The good agreement between the discretization-based and previous results shows the accuracy of the proposed mechanism, proving that it can be an alternative and reliable approach for complex slope stability analysis.

A technique for capturing structural crack geometry in numerical simulation based on the invariant level set method

  • Tao Wang;Shangtao Hu;Menggang Yang;Shujun Fang
    • Structural Engineering and Mechanics
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    • 제87권3호
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    • pp.243-254
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    • 2023
  • Engineering structures usually suffer from cracks. The crack geometry has an influence on the structural mechanical properties and subsequent crack propagations. However, as an extensively utilized method in fracture analysis, the extended finite element method provided by Abaqus fails to output the specific location and dimensions of fractures. In this study, a technique to capture the crack geometry is proposed. The technique is based on the invariant level set method (I-LSM), which can avoid updating the level set function during crack development. The solution is achieved by an open-source plug-in programmed by Python. Three examples were performed to verify the effectiveness and robustness of the program. The result shows that the developed program can accurately output the crack geometry in both the 2D and 3D models. The open-source plug-in codes are included as supplementary material.

Adaptive Input-Output Linearization Technique of Interior Permanent Magnet Synchronous Motor with Specified Output Dynamic Performance

  • Kim, Kyeong-Hwa;Baik, In-Cheol;Moon, Gun-Woo;Lee, Dae-Sik;Youn, Myung-Joong
    • Journal of Electrical Engineering and information Science
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    • 제1권2호
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    • pp.58-66
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    • 1996
  • An adaptive input-output linearization technique of an interior permanent magnet synchronous motor with a specified output dynamic performance is proposed. The adaptive parameter estimation is achieved by a model reference adaptive technique where the stator resistance and the magnitude of flux linkage can be estimated with the current dynamic model and state observer. Using these estimated parameters, the linearizing control inputs are calculated. With these control inputs, the input-output linearization is performed and the load torque is estimated. The adaptation laws are derived by the Popov's hyperstability theory and the positivity concept. The robustness and the output dynamic performance of the proposed control scheme are verified through the computer simulations.

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An Improved Detection Technique for Voltage Sag using the Wavelet Transform

  • Kim, Chul-Hwan;Lee, Jong-Po;Ahn, Sang-Pil;Kim, Byung-Chun
    • KIEE International Transactions on Power Engineering
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    • 제11A권4호
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    • pp.1-8
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    • 2001
  • This paper presents a discrete wavelet transform approach for detecting voltage sags initialized by fault conditions and starting of larger motors. The proposed technique is based on utilizing the summation value of D1(at scale 1) coefficients in multiresolution analysis(MRA) based on the discrete wavelet transform. In this paper, the proposed technique is tested under various cases of voltage sags. It is shown that the voltage sag detection technique based on the wavelet transform is a satisfactory and reliable method for detecting voltage sags in power quality disturbance analysis.

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Combined ML and QR Detection Algorithm for MIMO-OFDM Systems with Perfect ChanneI State Information

  • You, Weizhi;Yi, Lilin;Hu, Weisheng
    • ETRI Journal
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    • 제35권3호
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    • pp.371-377
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    • 2013
  • An effective signal detection algorithm with low complexity is presented for multiple-input multiple-output orthogonal frequency division multiplexing systems. The proposed technique, QR-MLD, combines the conventional maximum likelihood detection (MLD) algorithm and the QR algorithm, resulting in much lower complexity compared to MLD. The proposed technique is compared with a similar algorithm, showing that the complexity of the proposed technique with T=1 is a 95% improvement over that of MLD, at the expense of about a 2-dB signal-to-noise-ratio (SNR) degradation for a bit error rate (BER) of $10^{-3}$. Additionally, with T=2, the proposed technique reduces the complexity by 73% for multiplications and 80% for additions and enhances the SNR performance about 1 dB for a BER of $10^{-3}$.

The 2-DOF Control system design for Quadruple-Tank process using Root Locus Technique.

  • Arjin, Numsomran;Thanit, Trisuwannawat;Kitti, Tirasesth
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2004년도 ICCAS
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    • pp.1371-1374
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    • 2004
  • The control system design of 2-DOF for SISO process by root locus technique is not complicated and efficiently. It can design the control system to have the transient and steady state responses, and do not adjust the gain of process controller later. However, due to control system design for MIMO process, by root locus technique, there is not exact method. This paper is presents the control system design method for Quadruple-Tank Process, by using root locus technique for the structure of 2-DOF control system. The design procedures are first decentralized then using the relative gain array, and finally 2-DOF controller design is applied.

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An Efficient Soft Handoff Scheme Using Enhanced Resource Resonation Technique in Wireless MIPv6 Networks

  • Park, Tae-Hyun;Park, Ho-Ryong;Chun, Sang-Hun;Kwak, Kyung-Sup
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2002년도 ITC-CSCC -1
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    • pp.571-574
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    • 2002
  • In a recent wireless network environments, dynamic host configuration protocol (BHCP) service is used to assign IP addresses to mobile terminals. In IPv6 networks, it is necessary to introduce the concept of handoff to support a seamless service to mobile terminals. In a general soft handoff technique used by code-division multiple acces (CDMA) communication systems, the powers received to base station are simply compared to determine which base station will handle the signal to and from each mobile termins. However, in IPv6 network, to transmit data-oriented services, it is necessary to support an enhanced soft handoff technique with more security and quality of service. In this paper, we propose a scheme to reduce a signaling process of handoff in IPv6 network. Also, we propose a technique to reduce wasted reservation resources and to guarantee quality of service (QoS) using DHCP.

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클록 게이팅을 이용한 저전력 UART 설계 (A Low Power UART Design by Using Clock-gating)

  • 오태영;송승완;김희석
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2005년도 추계종합학술대회
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    • pp.865-868
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    • 2005
  • This paper presents a Clock-gating technique that reduces power dissipation of the sequential circuits in the system. The Master Clock of a Clock-gating technique is formed by a quaternary variable. It uses the covering relationship between the triggering transition of the clock and the active cycles of various flip-flops to generate a slave clock for each flip-flop in the circuit. At current RTL designs flip-flop is acted by Master clock's triggering but the Slave Clock of Clock-gating technique doesn't occur trigger when external input conditions have not matched with a condition of logic table. We have applied our clocking technique to UART controller of 8bit microprocess

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OCC에서의 이미지 처리 기술 (Image processing technique for Optical Camera Communication)

  • Nguyen, Trang;Le, Nam-Tuan;Jang, Yeong Min
    • 한국위성정보통신학회논문지
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    • 제9권3호
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    • pp.47-52
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    • 2014
  • 본 논문은 이미지 처리 기술을 이용한 광 카메라 통신(OCC: Optical Camera Communications) 기술을 제안한다. OCC 시스템의 구조 및 동작을 제안한다. 상용 30fps 카메라의 샘플링 동작에 의해 제한되는 데이터율을 증가시키기 위해 칼라 이미지 처리기술을 이용한 멀티칼러 전송기법을 제안한다. 멀티칼라 부호화 및 이미지 처리기반의 복호화 기법을 제안한다.

공진형 직류 링크단을 이용한 유도전동기의 예측형 전류 제어 (A Novel Predictive Current Control of Induction Motor Using Resonant DC Link Inverter)

  • 오인환;문건우;김성권;윤명중
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1996년도 하계학술대회 논문집 A
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    • pp.567-570
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    • 1996
  • A predictive current control technique for an induction motor employing a resonant DC link inverter is proposed to overcome the disadvantage of the current regulated delta modulation(CRDM) which was employed to control the resonant DC link inverter. The discrete model of an induction motor and estimation of back EMF are investigated and a novel predictive current control technique is newly developed based on this discrete model and estimated back EMF. Using the proposed control technique, the minimized current ripple with reduced offset can be obtained. The usefulness of the proposed technique is verified through the computer simulation.

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