• Title/Summary/Keyword: Transmission matrix

Search Result 601, Processing Time 0.023 seconds

Electromagnectic Modal Analysis for the Multiscreen Structure with Periodic Slot Array Including Conductor Thickness Effect (유한한 두께를 갖는 평판 상의 주기적 슬롯이 배열된 다중스크린 구조의 전자파 모드 해석)

  • 고지환;조영기
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.40 no.11
    • /
    • pp.1-9
    • /
    • 2003
  • The electromagnectic modal analysis method for the multiscreen structure with periodic slot array with including conductor thickness effect is presented. The multiscreen structure is seen to be exactly equivalent to a microwave guide closed by phase-shift walls. From this viewpoint, the entire generalized scattering matrix of the multiscreen structure is calculated by the cascade connection of the scattering matrices obtained by the modal analysis at guide junctions and the transmission matrices of guide region. The present method is verified in comparison with the results calculated by the previous method of moment for single screen structure. As an application example of the present method, the spatial filter having multiscreen structure is designed and the interesting characteristics such as transmission and reflection coefficient versus frequency & angle are investigated.

Analysis of Power Characteristics for a Hydromechanical Transmission Considering HSU Flow Loss (HSU의 유량손실을 고려한 정유압 기계식 변속기의 동력특성 해석)

  • Sung, Duk-Hwan;Lee, Geun-Ho;Kim, Hyoung-Eui;Kim, Hyun-Soo
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.26 no.6
    • /
    • pp.1149-1158
    • /
    • 2002
  • An improved hydrostatic unit(HSU) model is proposed by considering the flow loss in order to analyze the power flow characteristics of a hydromechanical transmission(HMT) and a network analysis algorithm is presented to determine the torque and speed of each element of the HMT. To calculate the torque and flow loss of a pump and a motor in HSU, an effort and flow concept is introduced, which can be used to establish a torque and speed matrix in the network analysis. It is found from the network analysis that magnitude of the HSU stroke increases to maintain the same output speed in order to compensate the flow Boss in the HSU and the efficiency of the HMT shows the lowest value in the 1st speed since the HSU has the largest flow loss in the 1st speed and the flow loss decreases as the speed ratio upshifts.

Research on Vibro-acoustic Coupled Analysis using Power Flow Finite Element Method (파워흐름유한요소법을 이용한 진동음향 연성해석 연구)

  • Kim, Sung-Hee;Kwon, Hyun-Wung;Hong, Suk-Yoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2006.11a
    • /
    • pp.767-770
    • /
    • 2006
  • To predict vibrational energy density of simple structural-acoustic coupled systems in medium-to-high frequency ranges, Power Flow Finite Element Method(PFFEM) is used, and PFFEM sofiware, PFADS has been developed for the vibration predictions and analysis of coupled system structures in medium-to-high frequency ranges. However, it needs to consider vibro-acoustic coupled analysis to get more accurate results. Prior to implement vibro-acoustic coupled analysis functions in PFADS, research on vibro-acoustic coupled analysis using PFFEH is performed for simple models. These predictions include the indirect transmission path associated, and also the direct transmission path, and the formulation is extended to structural system model by using appropriate modifications to structural-acoustic and acoustic-acoustic joint matrices. Concerning the waves in plate and acoustic, it is possible to calculate the structural-acoustic full matrix of a model using PFFEM, and the formulations developed are implemented for two rooms surrounded by plates.

  • PDF

A Study on The Available Transfer Capability(ATC) with Transient Stability Constraints (과도 안정도를 고려한 가용송전용량(ATC) 계산에 관한 연구)

  • Kim, Yang-Il;Jeong, Sung-Won;Gim, Jae-Hyeon
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.58 no.3
    • /
    • pp.437-443
    • /
    • 2009
  • In recent years, electric power systems have been experiencing a rapid change due to the increasing electricity market. For the effective use of power system under the deregulated environment, it is important to make a fast and accurate calculation of the maximum available transfer capability (ATC) from a supply point to a demand point. In this paper, the purpose of this research is to calculate ATC fast and accurately for securing the stability of system and raising the efficiency as a result of anticipating transmission congestion according to transmission open access progressed in the future under the regulated environment of electricity market. In this paper, a study utilized a relation of the potential energy and energy function by which calculated CCT and then utilized a relation of PEBS for transient stability ATC calculation. In this paper, ATC was calculated as RPF and Energy Function method and calculation results of each method was compared. Contingence ranking method decided the weak bus by the Eigenvalues of Jacobian matrix and overloading branches by PI-index. As a result, a study proved the fast and accurate ATC calculation method considering transient stability suggested in this paper. Through the case study using New England 39 bus system, it is confirmed that the proposed method can be used for real time operation and the planning of electric market.

Adaptive Opimization of MIMO Codebook to Channel Conditions for Split Linear Array (분할된 선형배열안테나를 위한 채널 환경에 적응하는 MIMO 코드북 최적화)

  • Mun, Cheol;Jung, Chang-Kyoo;Kwak, Yun-Sik
    • Journal of Advanced Navigation Technology
    • /
    • v.13 no.5
    • /
    • pp.736-741
    • /
    • 2009
  • In this paper, adaptive optimizations of precoder codebook to channel conditions is proposed for a multiuser multiple-input multiple-output (MIMO) system with split linear array and limited feedback. We propose adaptive method for constructing a precoder codebook by coloring the random vector quantization codebook at each link by using limited long-term feedback information on transmit correlation matrix of each link. It is shown that the proposed multiuser MIMO codebook design scheme outperforms existing multiuser MIMO codebook design schemes for various channel conditions in terms of the average sum throughput of multiuser MIMO systems using zero-forcing maximum eigenmode transmission and limited feedback.

  • PDF

A Study on Encrypted Matrix Puzzle for Digital Contents Protection (디지털 컨텐츠 보호를 위한 메트릭스 퍼즐 암호화방법에 대한 연구)

  • Min, So-Yeon;Kim, Jung-Jae
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.9 no.4
    • /
    • pp.936-944
    • /
    • 2008
  • DRM system is a technology that protects and manages copyright holder's privilege by using a copyright protection technology. This paper contributes to improvement of the secret key transmission and encryption/decryption processing time base on DRM system. In this paper, we will suggest that as follow: First, we will propose the algorithm to transmit the encryption key which use Multidimensional Method more safe than the existing One-path XOR method. Second, we will provide the high quality algorithm of security than the existing system because the Multidimensional which generated from the algorithm does not saved to the server side. Third, we will support the client decryption system which can decrypt the Multidimensional with OPT in decryption with client side. Fourth, we will adopt the more safr method of transmission with the compound of Multidimensional Method and OPT.

Cooperative Transmission Scheme in OFDMA Uplink System (OFDMA 상향 시스템에서의 협동 전송 기법)

  • Yoon, Jae-Seon;Song, Hyoung-Kyu
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.32 no.5A
    • /
    • pp.475-483
    • /
    • 2007
  • Recently, consumers demand high-quality wireless multimedia services via terrestrial and satellite network. And the interest for new services to sustain its successful commercial deployment grows tremendously. So, the MIMO schemes, such as STCs, MRC, has been used for realizing high reliability. However, MIMO schemes has some limitations. MIMO scheme needs more size, cost, and hardware complexity to employ additional antennas. Moreover, sufficient spaces between antennas are required to guarantee the independence of each channel and the devices which use multiple antennas should be enlarged. A cooperative transmission technique which is detect and forward type applying virtual MIMO with STBC matrix in DVB-RCT(Digital Video Broadcasting with Return Channel via Terrestrial) system based on OFDMA is also proposed.

Microstructure of Cured Urea-Formaldehyde Resins Modified by Rubber Latex Emulsion after Hydrolytic Degradation

  • Nuryawan, Arif;Park, Byung-Dae
    • Journal of the Korean Wood Science and Technology
    • /
    • v.42 no.5
    • /
    • pp.605-614
    • /
    • 2014
  • This study investigated microstructural changes of cured urea-formaldehyde (UF) resins mixed with aqueous rubber latex emulsion after intentional acid etching. Transmission electron microscopy (TEM) was used in order to better understand a hydrolytic degradation process of cured UF resins responsible for the formaldehyde emission from wood-based composite panels. A liquid UF resin with a formaldehyde to urea (F/U) molar ratio 1.0 was mixed with a rubber latex emulsion at three different mixing mass ratios (UF resin to latex = 30:70, 50:50, and 70:30). The rate of curing of the liquid modified UF resins decreased with an increase of the rubber latex proportion as determined by differential scanning calorimetry (DSC) measurement. Ultrathin sections of modified and cured UF resin films were exposed to hydrochloric acid etching in order to mimic a certain hydrolytic degradation. TEM observation showed spherical particles and various cavities in the cured UF resins after the acid etching, indicating that the acid etching had hydrolytically degraded some part of the cured UF resin by acid hydrolysis, also showing spherical particles of cured UF resin dispersed in the latex matrix. These results suggested that spherical structures of cured UF resin might play an important role in hindering the hydrolysis degradation of cured UF resin.

A Study on Thermal Conductivity Measurement and Optical Characteristics of Thin Films (박막의 열물성 측정 및 광학특성 연구)

  • Gwon, Hyuk-Rok;Lee, Seong-Hyuk
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.56 no.12
    • /
    • pp.2202-2207
    • /
    • 2007
  • The present article investigates experimentally and theoretically thermal and optical characteristics of thin film structures through measurement of thermal conductivity of Pyrex 7740 and reflectance in silicon thin film. The 3ω method is used to measure thermal conductivity of very thin film with high accuracy and the optical characteristics in thin films are studied to examine the influence of incidence angle of light on reflectance by using the CTM(Characteristics Transmission Method) and the 633 nm He-Ne laser reflectance measurement system. It is found that the estimated reflectance of silicon show good agreement with experimental data. In particular, the present study solves the EPRT(Equation of Phonon Radiative Transport) which is based on Boltzmann transport equation for predicting thermal conductivity of nanoscale film structures. From the results, the measured thermal conductivity is in good agreement with the previous published data. Moreover, thermal conductivities are estimated for different film thickness. It indicates that as film thickness decreases, thermal conductivity decreases substantially due to internal scattering.

Development of a New 6-DOF Parallel-type Motion Simulator (6자유도 병렬형 모션 시뮬레이터 개발)

  • Kim, Han-Sung
    • Journal of the Korean Society of Manufacturing Technology Engineers
    • /
    • v.19 no.2
    • /
    • pp.171-177
    • /
    • 2010
  • This paper presents the development of a new 6-DOF parallel-kinematic motion simulator. The moving platform is connected to the fixed base by six P-S-U (Prismatic-Spherical-Universal) serial chains. Comparing with the well-known Gough-Stewart platform-type motion simulator, it uses commercialized linear actuators mounted at the fixed base whereas a 6-UPS manipulator uses telescopic linear ones. Therefore, the proposed motion simulator has the advantages of easier fabrication and lower inertia over a 6-UPS counterpart. Furthermore, since most forces acting along the legs are transmitted to the structure of linear actuators, smaller actuation forces are required. The inverse position and Jacobian matrix are analyzed. In order to further increase workspace, inclined arrangement of universal joints is introduced. The optimal design considering workspace and force transmission capability has been performed. The prototype motion simulator and PC-based real-time controller have been developed. Finally, position control experiment on the prototype has been performed.