• Title/Summary/Keyword: fundamental parameters

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Characteristics of Cow´s Voices in Time and Frequency domains for Recognition

  • Ikeda, Yoshio;Ishii, Y.
    • Agricultural and Biosystems Engineering
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    • v.2 no.1
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    • pp.15-23
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    • 2001
  • On the assumption that the voices of the cows are produced by the linear prediction filter, we characterized the cows’voices. The order of this filter was determined by examining the voice characteristics both in time and frequency domains. The proposed order of the linear prediction filter is 15 for modeling voice production of the cow. The characteristics of the amplitude envelope of the voice signal was investigated by analyzing the sequence of the short time variance both in time and frequency domains, and the new parameters were defined. One of the coefficients o the linear prediction filter generating the voice signal, the fundamental frequency, the slope of the straight line regressed from the log-log spectra of the short time variance and the coefficients of the linear prediction filter generating the sequence of the short time variance of the voice signal can differentiate the two cows.

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THE ENVIRONMENTAL DEPENDENCE OF THE FRACTION OF 'UNCONVENTIONAL' GALAXIES: FAINT RED AND LUMINOUS BLUE

  • Deng, Xin-Fa;Zhang, Fuyang;Song, Jun;Chen, Yi-Qing;Jiang, Peng
    • Journal of The Korean Astronomical Society
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    • v.45 no.3
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    • pp.59-64
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    • 2012
  • Using the volume-limited Main galaxy sample constructed from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7), we explore the environmental dependence of the fraction of 'unconventional' galaxies: luminous blue and faint red. It is found that the fraction of faint red increases apparently with increasing local density, and the fraction of luminous blue declines substantially with increasing local density, which shows that there is an environmental dependence for color beyond that for luminosity.

Induced Second Order Optical Nonlinearity in Thermally Poled Silica Glasses (Poling된 실리카 유리의 2차비선형광학효과와 공간전하분극의 관계)

  • 신동욱
    • Journal of the Korean Ceramic Society
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    • v.36 no.12
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    • pp.1374-1380
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    • 1999
  • The cause of Scond Harmonic Generation (SHG) in thermally poled silica glass is suggested basedon the electrical and dielectric relaxation measurements. The absorption currents as functions of time were measured for various types of silica glasses and analyzed by the theory of Space Charge Polarization. Space charge polarization occurs when an ionic conducting material is subjected to dc electric field with blocking electrode. Thermal poling performed to induce SHG in silica glass is basically identical to the process generating space charge polarization. Hence it was found that gene-ration removal reproduction and temperature dependence of SHG in poled silica is directly related to those of space charge polarization. It turned out that the fundamental parameters governing the SHG in poled silica are charge carrier concentration and mobility. Based on the theory of space charge polarization and experimental results of electrical rela-xation the method to increase the intensity of SHG is proposed.

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Study on Seismic Responses for Base Isolated Structure Using Linear 2 DOF System and Its Application for NPP (선형 2자유도계를 이용한 면진구조물의 지진응답 연구 및 원자력발전소 적용)

  • Yoo, Bong;Lee, Jae-Han
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 1997.04a
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    • pp.225-232
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    • 1997
  • A study of effects of design parameters on the seismic responses of base isolated structure is performed to reduce the seismic responses using a linear tw0-degree of freedom system and a lumped-mass model of a nuclear power p;ant(NPP). From the simplified 2 DOF system the optimal isolation frequency being less than 1/10th of the fundamental frequency of superstructure is obtained, and the isolator damping minimizing the peak acceleration depends on superstructure frequency. From the time history analyses for lumped mass model of NPP the optimal damping is calculated as 40% in containment building and 65% in reactor internal structure. Similar results are obtained in 2 DOF system

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Investigation of vibration and stability of cracked columns under axial load

  • Ghaderi, Masoud;Ghaffarzadeh, Hosein;Maleki, Vahid A.
    • Earthquakes and Structures
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    • v.9 no.6
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    • pp.1181-1192
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    • 2015
  • In this paper, an analytical method is proposed to study the effect of crack and axial load on vibration behavior and stability of the cracked columns. Using the local flexibility model, the crack has been simulated by a torsional spring with connecting two segments of column in crack location. By solving governing eigenvalue equation, the effects of crack parameters and axial load on the natural frequencies and buckling load as well as buckling load are investigated. The results show that the presents of crack cause to reduction in natural frequencies and buckling load whereas this reduction is affected by the location and depth of the crack. Furthermore, the tensile and compressive axial load increase and decrease the natural frequencies, respectively. In addition, as the compression load approaches to certain value, the fundamental natural frequency reaches zero and instability occurs. The accuracy of the model is validated through the experimental data reported in the literature.

The Relation between the Welding Conditions and Distortions of a Bead Weld on a Rectangular Plate -Transverse Shrinkage and Angular Distortion- (사각평판상(四角平板上)의 Bead용접(熔接)으로 인(因)한 변형(變形)과 용접(熔接) 조건(條件)과의 관계(關係) -횡수축(橫收縮)과 각변화(角變化)-)

  • J.E.,Park;E.H.,Kim
    • Bulletin of the Society of Naval Architects of Korea
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    • v.16 no.3
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    • pp.25-33
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    • 1979
  • The relation between the welding conditions and welding distortions were studied with the weld parameters, current, welding speed and plate thickness, and the form of the distortions were derived theoretically. To derive these formulas, the temperature distribution on the plane normal to the direction of the weld line was assumed to be parabolic. Both the theoretical studies for the transverse shrinkage and angular distoction were compared with the experiments. The experiments were performed on the fundamental cases of a bead welds on rectangular mild steel plates. It was found that the distoction formulas were in good agreement with the results of the experiments. The formulas for the calculation of the distortion were established for the case of bead on plate weld using rectangular mild steel plate and the KS E4313, $4mm\phi$ welding rod.

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An Analysis of a Thermo-plastic Melt Flow in the Metering Zone of a Polymer Extruder (고분자 압출기에 있어서 계량부 용융수지의 유동해석)

  • Choi, Man Sung;Kim, Kwang Sun
    • Journal of the Semiconductor & Display Technology
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    • v.11 no.4
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    • pp.7-12
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    • 2012
  • Extrusion is one of the most important operations in the polymer-processing industry. Development of models for extrusion and computer tools offer a route to developing reliable and optimized process designs. The models are based on the analysis of physical phenomena encountered during the process. Balance equations for mass, momentum and energy are fundamental to the problem. A predictive computer model has been developed for the single screw extruders with conventional screws of different geometry. The model takes into account melting zones of the extruder and describes an operation of the extruder system, making it possible to predict mass flow rate of the polymer, pressure and velocity profiles along the extruder screw channel. The simulation parameters are the material and rheological properties of the polymer; the screw pitch, and screw speed.

A Study on Heat Transfer Performances of a Heat Pipe Heat Sink for Power Control Semiconductors (전력제어 반도체용 히트파이프 냉각기의 열전달 성능 연구)

  • 강환국;김재진;김철주
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.8
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    • pp.701-709
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    • 2001
  • In this days, heat pipe heat sink has been widely applied to power controllers for railway substations to remove heat from power semiconductors(diodes or thyristors). The heat pipe heat sink consists of a aluminum heating block for mounting the thyristor, 2~3 heat pipes and large number of aluminum fins. The present study was to get fundamental informations of the structure, design parameters and heat transfer performances of heat pipe heat sink. Series of operational test for a unit with 3 heat pipes were performed and its heat flow circuit was analysed from the experimentally obtained data on wall temperature distribution. Total resistance was ranged 0.02~$0.03^{\circ}C$/W for a power range from 40W to400W. The time to get the steady state was approximately longer than 20 minutes, and overshooting was not occurred during start up operation.

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Development of a Linearized Model and Verification of the Exact Solution for the Analysis of a Desiccant Dehumidifier (제습기 성능분석을 위한 선형화 모델 및 해석해의 검증)

  • 이길봉;이대영;김민수
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.9
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    • pp.811-819
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    • 2004
  • A silica gel desiccant dehumidifier is studied theoretically in this paper adopting several linearization assumptions. The governing equations are linearized with the assumptions, and the exact solutions to the temperature and the humidity ratio are obtained. In spite of the assumptions, the theoretical results are found to agree well with those from the numerical analysis without any assumption. In typical operation ranges of the desiccant dehumidifier, the time-averaged errors in the process air temperature and humidity ratio are less than 4% and 7%, respectively, and the corresponding root-mean-square values are less than 5% and 15%, respectively The analytical solutions are expected to contribute to the fundamental understanding of the dehumidification and regeneration processes and the correlation analysis of the numerous parameters influencing the dehumidifier operation.

Natural Frequencies of Nonsymmetrically Tapered Beams (비대칭 변단면 보의 고유진동수)

  • 백봉인;안성기;김순철;이수곤
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1999.10a
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    • pp.267-274
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    • 1999
  • An understanding of the natural frequencies of a beam is virtually a prerequisite to the understanding of its response in forced vibration due to shock, ground acceleration or moving loads. Contrary to the frequencies of the prismatic bars with arbitrary boundary conditions, those of a tapered bar are hard to determine when one employs convevtional neutral equilibrium or energy method. In this paper, finite element method is adopted to determine the fundamental frequencies of the non-symmetrically tapered bars. The bars assume the shapes of straight lines along the axis. The parameters considered in this study are sectional parameter, m,n and taper parameter, $\alpha$ For the structural engineer's convenience, the results by finite element method are expressed by simple algebraic equations, by which first mode frequencies are easily estimated. And they agree fairy well with those by F.E.M in most cases.

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