• Title/Summary/Keyword: multi-modem

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Multi-Constant Modulus Algorithm for Blind Decision Feedback Equalizer (블라인드 결정 궤환 등화기를 위한 다중 계수 알고리즘)

  • Kim, Jung-Su;Chong, Jong-Wha
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.39 no.6
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    • pp.709-717
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    • 2002
  • A new multi constant modulus algorithm (MCMA) for a blind decision feedback equalizer is proposed. In order to avoid the error propagation problem in the conventional DFE structure, Feed-Back Filter coefficients are updated only after Feed-Forward Filter coefficients are sufficiently converged to the steady state. Therefore, it has the problem of slow convergence speed characteristics. To overcome this drawback, the proposed MCMA algorithm uses not only new cost function considering the minimum distance between the received signal and the representative value containing the statistical characteristics of the transmitted signal, but also adaptive step-size according to the equalizer outputs to fast convergence speed of FBF. Simulations were carried out under the certified communication channel environment to evaluate a performance of the proposed equalizer. The simulation results show that the proposed equalizer has an improved convergence and SER performance compared with previous methods. The proposed techniques offer the possibility of practical equalization for cable modem and terrestrial HDTV broadcast (using 8-VSB or 64-QAM) applications.

Efficient Storage Techniques for Multidimensional Index Structures in Multi-Zoned Disk Environments (다중 존 디스크 환경에서 다차원 인덱스 구조의 효율적 저장 기법)

  • Yu, Byung-Gu;Kim, Seon-Ho;Chang, Jae-Young
    • Journal of KIISE:Databases
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    • v.34 no.4
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    • pp.315-327
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    • 2007
  • The performance of database applications with large sets of multidimensional data depends on the performance of its access methods and the underlying disk system. In modeling the disk system, even though modem disks are manufactured with multiple physical zones, conventional access methods have been developed based on a traditional disk model with many simplifying assumptions. Thus, there is a marked lack of investigation on how to enhance the performance of access methods given a zoned disk model. The paper proposes novel zoning techniques that can be applied to any multidimensional access methods, both static and dynamic, enhancing the effective data transfer rate of underlying disk system by fully utilizing its zone characteristics. Our zoning techniques include data placement algorithms for multidimensional index structures and accompanying localized query processing algorithms for range queries. The experimental results show that our zoning techniques significantly improve the query performance.

Development and Validation of Multi-Purpose Geostatistical Model with Modified Kriging Method (수정된 Kriging법을 응용한 다목적지구통계모델의 개발 및 타당성 검토)

  • Kim, In-Kee;Sung, Won-Mo;Jung, Moon-Young
    • Economic and Environmental Geology
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    • v.26 no.2
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    • pp.207-215
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    • 1993
  • In modem petroleum reservoir engineering, the characterization of reservoir heterogeneities is very important to accurately understand and predict reservoir production performance. Formation evaluation for the description of reservoir is generally conducted by performing the analysis of well logging, core testing, and well testing. However, the measured data points by well logging or core testing are in general very sparse and hence reservoir properties should be interpolated and extrapolated from measured points to uncharacterized areas. In assigning the data for the unknown points, simple averaging technique is not feasible as optimum estimation method since this method does not account the spatial relationship between the data points. The main goal of this work is to develop PC-version of multi-purpose geostatistical model in which several stages are systematically proceeded. In the development of model, the simulator employs a automatic selection of semivariogram function such as exponential or spherical model with the best values of $R^2$. The simulator also implements a special algorithm for the fitting of semivariogram function to experimental sernivariogram. The special algorithm such as trial and error scheme is devised since this method is much more reliable and stable than Gauss-Newton method. The simulator has been tested under stringent conditions and found to be stable. Finally, the validity and the applicability of the developed model have been studied against some existing actual field data.

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Performance of 8SQAM System in a Nonlinearly Amplified SCPC-FDMA Channel Interference Environment (비선형 증폭 SCPC-FDMA 채널 간섭 환경에서 8SQAM 시스템의 성능)

  • 성봉훈;서종수
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.7C
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    • pp.678-687
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    • 2003
  • 8SQAM(8-state Superposed Quadrature Amplitude Modulation) being a new modem technique for use in power and bandwidth limited digital communication system generates output signals which have a mか and continuous phase transition and a reduced envelope fluctuation by keeping correlation between amplitudes and phases of two subsequent symbols. Also, 8SQAM signal is free of inter-symbol interference(ISI), and has a compact power spectrum. Accordingly 8SQAM, as compared with a conventional 8PSK, is influenced a little by inter-modulation(IM), inter-symbol interference(ISI) and adjacent channel interference(ACI) in a nonlinearly amplified multi-channel(SCPC-FDMA) environment. In this paper, the performance of 8SQAM system in a nonlinearly amplified multi-channel interference environment is analyzed via computer simulation The simulation result shows that 8SQAM outperforms 8PSK with roll-off value of $\alpha$ = 0.3 by 2.7dB in CNR to maintain BER=1$\times$10$^{-4}$ when input back-off(IBO) of HPA is 1dB and channel space is 41.7% of the data bit rate(i.e., spectral efficiency = 2.40b/s/Hz).

LTE-Based Macro Base Station Platform Architecture (LTE 기반 Macro 기지국 Platform 구조 연구)

  • Jeong, Chan-Bok;Bae, Hyeon-Deok
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39C no.9
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    • pp.861-869
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    • 2014
  • This paper shows the research of a platform architecture relates to the LTE-based macro basestation; the proposed platform architecture is designed with the interface between the baseband signal and IF (Intermediate Frequency) per codeword. Using this method, we can smoothly transmit/receive a large amounts of data regardless of the number of antenna in a macro base station which is used technology such as massive MIMO. In this paper, We analyzed the evolution of LTE technology and the trend in the development of the LTE-based system. For validation of the proposed architecture, we compare the general architecture of a conventional with the proposed architecture. From the calculation results of transmission quantity data, we see that the proposed architecture can give better performance than the existing architecture. By presenting this architecture, we hope to provide a new foundation for Design and Implementation of a LTE base station platform which is used technology such as massive MIMO, carrier aggregation (CA), coordinated multi point (CoMP).

A Study on Module Furniture Design -Focus on Reiteration and Expansion- (모듈(Module) 가구디자인에 대한 연구 -반복(Reiteration)과 확장(Expansion)을 중심으로-)

  • Lee, Hyun-Jung
    • Journal of the Korea Furniture Society
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    • v.19 no.1
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    • pp.55-65
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    • 2008
  • The forms made by repeated arrangements of basic units defined as Simulakre are recomposed into organic, geometric or multi-functional forms by diverse combinations and arrangements and the space expanded by reiterated compositions will have the meaning of active space expansions representing speeds, rhythms or time by reiterations instead of a limited and fixed place shown by a work. The module design that can create new roles and functions of spaces that are variability and fluidity and that can be assembled and transformed into the shapes, sizes and functions desired by users will be analyzed applying the concepts of reiteration and expansion. The module designs emerging in 21th century are in diverse organic forms and geometric forms and their methods for expansion are also diversified. And instead of having a function, they have diverse functions such as storages, partitions, walls, curtains and soundproofing. The development of module designs are first to satisfy the diversified needs, individualities and desires to posses of modem people and second the development, finding and application of new materials. In the future spaces that will continuously develop and will be nomadic, the flexible and individualized module designs will become more diversified and will have their significances.

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System Design of High-Definition Media Transceiver based on Power Line Communication and Its Performance Analysis (전력선 통신 기반 HD급 미디어 전송 시스템 설계 및 성능 분석)

  • Kim, Ji-Hyoung;Kim, Kwan-Woong;Kim, Yong-K.
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.1
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    • pp.192-196
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    • 2010
  • Due to a development of a modem technology as Power Line Communication(PLC) over 200 Mbps, the high-speed multi-media data trasmission could be currently possible. The strength of the PLC has no more additional wiring work. PLC has also possible to high quality data transmission with currently electrical cable. It has a various strong point campare with existing wire and wireless communication technologies. In This paper we develop a high quality media transmitter-receiver based on merging the HomePlug AV, which is 200 Mbps class PLC technology and HDMI Interface technology. The video function was used for the VEDEO TEST GENERATOR in order to a property valuation. Smart Live 6 software were used for the assessment of audio property. As the result of measurement of the HD class images by capturing from the receiver of the PLC, the quality of images couldn't be confirm any deterioration, which has compared with original reflections. In case of audio part as the result of confirmation of the Phase, Magnitude, it has been confirmed that over 90% of nomal transmition and receiving of acoustic signal. It can be possible to have HD class Media service through the PLC.

A Study on the Characteristics of Expression of Time-Space Concept in Media Art (미디어 아트에 나타난 시공간 개념의 표현 특성에 관한 연구)

  • Seo, Kyoung-Won;Lim, Kyung-Ran
    • Korean Institute of Interior Design Journal
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    • v.16 no.2 s.61
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    • pp.347-356
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    • 2007
  • The concept of time-space to be seen in the modem society has complex features at the points of scientific, philosophical, artistic, religious point of view. It has been brought up at a points of neo centric religious, philosophical view and then after, phenomenal approach and scientific approach were rendered through Newton and Einstein and so many scholar approaches affected the artistic field significantly. With such visual expression, it has affected the paintings for a long time till the 19th century, and then has affected various fields such as photography, film, video, computer, architecture and has currently affected the various space expressive of our daily lives and virtual space of digital. This study is to extract a visual and expressionistic characteristic through historical examination and multi-scholar analysis of time-space concept. Especially, by expanding the previous time and space concept, experimental cases and expressionistic characteristics has come up on the media art that offers various experience and by analyzing the expressionistic characteristics of the time-space concept expressed in media art, it is to extract the basic factors for the diversity of space experience.

QualNet based Linked Simulation Method for WAVE Physical Layer (QualNet 기반의 WAVE 물리계층 연동 시뮬레이션 방안)

  • Kwak, Jae-Min;Park, Kyung-Won
    • Journal of Advanced Navigation Technology
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    • v.13 no.3
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    • pp.351-357
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    • 2009
  • In this paper, we studied an efficient inter-working method in which QualNet network simulator can import WAVE channel model and physical layer simulation module pre-designed by Matlab tool. At first, we investigated physical layer and communication medium simply designed in QualNet, then we suggested practical method for QualNet network simulator to adopt different type of physical layer simulation module in which detailed multi-path fading channel model and IEEE802.11p communication modem are designed. This work should be applied to linked simulation between upper layer and lower physical layer for total simulation from higher layer to lower physical layer related to next generation DSRC/WAVE specification.

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Analysis of Correlativity with Blood Pressure and Measurement of Brain Blood Pressure(BBP) (뇌혈압 측정과 상완 혈압의 상관성 분석)

  • Ko, Su-Bok;Lee, Yong-Heum;Kim, Sung-Gon;Jeong, Dong-Myong
    • Proceedings of the KIEE Conference
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    • 2001.11c
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    • pp.180-183
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    • 2001
  • In modem city life, the citizen get insufficient exercise and has high levels of stress. Increased Stress causes such minor things as tiredness, disease and mental fatigue, and increase brain blood pressure too. In this paper trying to design the multi-functional blood pressure monitor with airo-dynamic brain hemokinesis improvement function. So this system have developed for the improvement of flows in the capillary blood vessel of head and limbs. Also This system is able to measure brain blood pressure(BBP) which need diagnosis circulation state of brain blood. So, we extracted correlativity of blood pressure(BP) and BBP through clinical experiment. We confirmed that compare factor of BP with BBP is more useful factors for diagnosis state of brain hemokinesis.

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