• Title/Summary/Keyword: superposition

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A Study on the Sensorless PMSM Control using the Superposition Theory

  • Lee, Young-Jin;Yoon, Young-Jin;Kim, Young-Ho;Lee, Man-Hyung
    • International Journal of Precision Engineering and Manufacturing
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    • v.4 no.2
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    • pp.5-12
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    • 2003
  • This study presents a solution to control a PMSM without sensors. The control method is the presented superposition principle. This method of sensorless theory is very simple to compute estimated angle. Therefore, computing time to estimate angle is shorter than other sensorless methods. The use of this system yields enhanced operations, fewer system components, lower system costs, efficient energy control system designs and increased efficiencies. A practical solution is described and its results are given in this study. The performance of a sensorless architecture allows an intelligent approach to reduce the complete system costs of digital motion control applications using the cheaper electrical sensorless motors. This paper deals with an overview of solutions in the sensorless PHSM control applications, whereby the focus will be the new sensorless controller and its applications.

Optimal Sensing Time for Maximizing the Throughput of Cognitive Radio Using Superposition Cooperative Spectrum Sensing

  • Vu-Van, Hiep;Koo, Insoo
    • Journal of information and communication convergence engineering
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    • v.13 no.4
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    • pp.221-227
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    • 2015
  • Spectrum sensing plays an essential role in a cognitive radio network, which enables opportunistic access to an underutilized licensed spectrum. In conventional cooperative spectrum sensing (CSS), all cognitive users (CUs) in the network spend the same amount of time on spectrum sensing and waste time in remaining silent when other CUs report their sensing results to the fusion center. This problem is solved by the superposition cooperative spectrum sensing (SPCSS) scheme, where the sensing time of a CU is extended to the reporting time of the other CUs. Subsequently, SPCSS assigns the CUs different sensing times and thus affects both the sensing performance and the throughput of the system. In this paper, we propose an algorithm to determine the optimal sensing time of each CU for SPCSS that maximizes the achieved system throughput. The simulation results prove that the proposed scheme can significantly improve the throughput of the cognitive radio network compared with the conventional CSS.

Nonlinear Wave Interaction of Three Stokes' Waves in Deep Water: Banach Fixed Point Method

  • Jang, Taek-S.;Kwon, S.H.;Kim, Beom-J.
    • Journal of Mechanical Science and Technology
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    • v.20 no.11
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    • pp.1950-1960
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    • 2006
  • Based on Banach fixed point theorem, a method to calculate nonlinear superposition for three interacting Stokes' waves is proposed in this paper. A mathematical formulation for the nonlinear superposition in deep water and some numerical solutions were investigated. The authors carried out the numerical study with three progressive linear potentials of different wave numbers and succeeded in solving the nonlinear wave profiles of their three wave-interaction, that is, using only linear wave potentials, it was possible to realize the corresponding nonlinear interacting wave profiles through iteration of the method. The stability of the method for the three interacting Stokes' waves was analyzed. The calculation results, together with Fourier transform, revealed that the iteration made it possible to predict higher-order nonlinear frequencies for three Stokes' waves' interaction. The proposed method has a very fast convergence rate.

A Study on Software Reliability Assessment Model of Superposition NHPP (중첩 NHPP를 이용한 소프트웨어 신뢰도 평가 모형 연구)

  • Kim, Do-Hoon;Nam, Kyung-H.
    • Journal of Korean Society for Quality Management
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    • v.36 no.1
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    • pp.89-95
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    • 2008
  • In this paper, we propose a software reliability growth model based on the superposition cause in the software system, which is isolated by the executed test cases in software testing. In particular, our model assumes an imperfect debugging environment in which new faults are introduced in the fault-correction process, and is formulated as a nonhomogeneous Poisson process(NHPP). Further, it is applied to fault-detection data, the results of software reliability assessment are shown, and comparison of goodness-of-fit with the existing software reliability growth model is performed.

Efficiency Improvement of Pulsed Nd:YAG Laser using Pulse Superposition Technique (펄스중첩기술을 적용한 펄스형 Nd:YAG 레이저의 효율개선)

  • Kwak, B.G.;Jung, J.H.;Lee, D.H.;Hong, J.H.;Kim, H.J.;Cho, J.S.
    • Proceedings of the KIEE Conference
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    • 1997.07e
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    • pp.1864-1866
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    • 1997
  • In this study, we designed the pulse superposition network consisting of a six-mesh and a three-mesh network, and fabricated the electrical power supply and the single elliptical resonator. We have developed a tec.bnique forming the step-pulse shape of pulsed Nd:YAG laser by using one shot multivibrater and have studied on the effect of two pulses superposition for the output and efficiency improvement of pulsed Nd:YAG laser by superposing a sinusoidal pulse on a main pulse.

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Effect of Basis Set Superposition Error on the MP2 Relative Energies of Gold Cluster Au6

  • Kim, Kyoung-Hoon;Kim, Jong-Chan;Han, Young-Kyu
    • Bulletin of the Korean Chemical Society
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    • v.30 no.4
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    • pp.794-796
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    • 2009
  • We have studied the structures and stabilities of Au6 to explore the origin of the large discrepancy between relative energies obtained from the density functional theory (DFT) and ab initio correlated levels of theory. The MP2 methods significantly overestimate the stability of the non-planar isomer when the double-$\zeta$ polarization quality of basis sets, such as LANL2DZ+1f and CEP31G+1f, are used. However, we show that such preference for the non-planar structure at the MP2 level mainly originates from the large basis set superposition error.

Hybrid Method to Compute the Cell Loss Probability in a Multiplexer with the Superposition of Heterogeneous ON/OFF Sources (이질적 ON/OFF 원을 입력으로 한 다중화 장치의 셀 손실률 계산을 위한 하이브리드 방법)

  • Hong, Jung-Sik;Kim, Sang-Baik
    • IE interfaces
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    • v.12 no.2
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    • pp.312-318
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    • 1999
  • This paper considers the cell loss probability(CLP) in a multiplexer with the superposition of heterogeneous ON/OFF sources. The input traffic is composed of k classes. Traffic of class i is the superposition of M_(i) ON/OFF sources. Recently, the method based on the Markov modulated deterministic process(MMDP) is presented. Basically, it is the discretized model of stochastic fluid flow process(SFFP) and gives the CLP very fast, but under-estimates the CLP especially when the value of estimated CLP is very low. This paper develops the discretized model of Markov modulated Poisson process(MMPP). It is a special type of switched batch Bernoulli process(SBBP). Combining the transition probability matrix of MMDP and SBBP according to the state which is characterized by the arrival rate, this paper presents hybrid algorithm. The hybrid algorithm gives better estimate of CLP than that of MMDP and faster than SBBP.

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A Design of X band Frequency Hopping Synthesizer using DDS Spurious Reduction Method (DDS 불요파 제거 알고리즘을 이용한 X 대역 주파수 도약 합성기 설계)

  • Kwon, Kun-Sup
    • Journal of the Korea Institute of Military Science and Technology
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    • v.13 no.5
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    • pp.775-784
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    • 2010
  • In this paper we propose a design method of X band frequency hopping synthesizer in terms of phase noise and settling time with DDS driven PLL architecture, which has the advantages of high frequency resolution, fast settling time and small size. In addition, a noble method is proposed to remove the synthesizer output spurious signals due to superposition effect of DDS. The spurious signal which depend on its normalized frequency of DDS, can be dominant if they occur within the PLL loop bandwidth. We verify that the sources of that spurious signals are quasi-amplitude modulation and superposition effect, and suggest that such signals can be eliminated by intentionally creating frequency errors in the developed synthesizer.

Spike Response Model and Coding of Neurons (뉴런의 스파이크 응답 모델과 코딩)

  • Lee, Ho-Suk
    • Proceedings of the Korean Information Science Society Conference
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    • 2007.06b
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    • pp.5-8
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    • 2007
  • This paper discusses the spike response model of neurons. First, this paper discusses the coding of spikes, the function of spikes, and the construction of the spikes of neurons by the superposition of simple kernel functions. This paper discusses the method of kernel superposition is general than the response of the IF (Integrate-and-Fire) neuron model, too. Next, this paper discusses the coincidence detection and the input weight computation of spiking neurons and the activity of neuron populations in some detail.

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Determination of Compound Stress Intensity Factor by Superposition Method (중첩법에 의한 복합응력확대계수의 결정)

  • 조재웅;한문식
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.11
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    • pp.244-250
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    • 1998
  • In this study, the stress intensity factors of center crack are analyzed when it is surrounded by symmetrically distributed small cracks. The values of stress intensity factors of the center crack are greatly influenced by the locations of distributed small cracks. When small cracks overlap or approach near the tip of a center crack, the effect of interaction arisen by these cracks becomes noticeable. In case of multiple distributed small cracks, the stress intensity factor of a center crack is found to be efficiently determined by the superposition method.

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