• Title/Summary/Keyword: Complex channel

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A Proactive Dynamic Spectrum Access Method against both Erroneous Spectrum Sensing and Asynchronous Inter-Channel Spectrum Sensing

  • Gu, Junrong;Jang, Sung-Jeen;Kim, Jae-Moung
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.6 no.1
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    • pp.361-378
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    • 2012
  • Most of the current frequency hopping (FH) based dynamic spectrum access (DSA) methods concern a reactive channel access scheme with synchronous inter-channel spectrum sensing, i.e., FH is reactively triggered by the primary user (PU)'s return reported by spectrum sensing, and the PU channel to be switched to is assumed precisely just sensed or ready to be sensed, as if the inter-channel spectrum sensing moments are synchronous. However, the inter-channel spectrum sensing moments are more likely to be asynchronous, which risks PU suffering more interference. Moreover, the spectrum sensing is usually erroneous, which renders the problem more complex. To address this problem, we propose a proactive FH based DSA method against both erroneous spectrum sensing and asynchronous inter-channel spectrum sensing (moments). We term it as proactive DSA. The optimal FH sequence is obtained by dynamic programming. The complexity is also analyzed. Finally, the simulation results confirm the effectiveness of the proposed method.

산업용품 유통합리화를 위한 유통단지조성에 관한 연구

  • Seol, Bong-Sik;Lee, Gyeong-Won;Kim, Ung-Jin
    • Journal of Distribution Research
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    • v.1 no.2
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    • pp.199-220
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    • 1996
  • Our courtry's distribrtion business is on the luring point by opening the market to foreign countries from this year. It can be said that industrial goods are intermediated goods for the production of other goods or service So it requires quality and specialty than any other things. But the lack of understanding, small scale and classification by non-productive industry by government bring about difficulty to the distribution itself and other fields. Industrial goods have a long distribution channel. This distribution stracture can be reduce the channel by establishment of distribution complex. Establishment of distribution complex will strengthen the role of quality management and go far toward quality improvement. This study examine the distribution status of industrial goods, problems and study the extablishment of complex and expected affect.

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Neural adaptive equalization of M-ary QAM signals using a new activation function with a multi-saturated output region (새로운 다단계 복소 활성 함수를 이용한 신경회로망에 의한 M-ary QAM 신호의 적응 등화)

  • 유철우;홍대식
    • Journal of the Korean Institute of Telematics and Electronics C
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    • v.35C no.1
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    • pp.42-54
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    • 1998
  • For decreasing intersymbol interference (ISI) due to band-limited channels in digitalcommunication, the uses of equalization techniques are necessary. Among the useful adaptive equalization techniques, because of their ease of implementation and nonlinear capabilites, the neural networks have been used as an alternative for effectively dealing with the channel distortion. In this paepr, a complex-valued multilayer percepron is proposed as a nonlinear adaptive equalizer. After the important properties that a suitable complex-valued activation function must possess are discussed, a new complex-valued activation function is developed for the proposed schemes to deal with M-ary QAM signals of any constellation sizes. It has been further proven that by the nonlinear transformation of the proposed function, the correlation coefficient between the real and imaginary parts of input data decreases when they are jointly Gaussian random variables. Lastly, the effectiveness of the proposed scheme is demonstrated by simulations. The proposed scheme provides, compared with the linear equalizer using the least mean squares (LMS) algorith, an interesting improvement concerning Bit Error Rate (BER) when channel distortions are nonlinear.

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Strong Uncorrelated Transform Applied to Spatially Distant Channel EEG Data

  • Kim, Youngjoo;Park, Cheolsoo
    • IEIE Transactions on Smart Processing and Computing
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    • v.4 no.2
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    • pp.97-102
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    • 2015
  • In this paper, an extension of the standard common spatial pattern (CSP) algorithm using the strong uncorrelated transform (SUT) is used in order to extract the features for an accurate classification of the left- and right-hand motor imagery tasks. The algorithm is designed to analyze the complex data, which can preserve the additional information of the relationship between the two electroencephalogram (EEG) data from distant channels. This is based on the fact that distant regions of the brain are spatially distributed spatially and related, as in a network. The real-world left- and right-hand motor imagery EEG data was acquired through the Physionet database and the support vector machine (SVM) was used as a classifier to test the proposed method. The results showed that extracting the features of the pair-wise channel data using the strong uncorrelated transform complex common spatial pattern (SUTCCSP) provides a higher classification rate compared to the standard CSP algorithm.

Performance Analysis of Co-Existence of DS-CDMA and TDMA System by Using Complex Multirate Filter Bank in Land Mobile Channel (육상 이동통신 채널에서 복소 다중비율 필터뱅크를 채용한 DS-CDMA/TDMA 공존 시스템의 성능 분석)

  • 우병훈;강희조
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.11 no.1
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    • pp.1-7
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    • 2000
  • In this paper, we proposed a complex multirate filter bank(CMRFB) based adaptive notch filtering technique to solve the co-existence narrowband interference problem of DS-CDMA and TDMA systems. We have discussed error performance of co-existence of DS-CDMA and TDMA system by using complex multirate filter bank in land mobile channel and computer simulation results show that the proposed scheme can eliminate the narrowband interference(TDMA signals) effectively.

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Power Line Channel Model Considering Adjacent Nodes with Reduced Calculation Complexity due to Multipath Signal Propagation and Network Size Using Infinite Geometric Series and Matrices (무한 등비급수와 행렬을 이용하여 멀티 패스 신호 전송과 네트워크 크기에 의한 계산의 복잡성을 줄이고 근접 노드의 영향을 고려한 전력선 통신 채널 모델)

  • Shin, Jae-Young;Jeong, Ji-Chai
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.2
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    • pp.248-255
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    • 2009
  • We proposed a power line channel model. We adopted advantages of other power line channel models to calculate channel responses correctly and simply. Infinite geometric series reduced the calculation complexity of the multipath signal propagation. Description Matrices were also adopted to handle the network topology easily. It represents complex power line network precisely and simply. Newly proposed model considered the effect of the adjacent nodes to channel responses, which have been not considered so far. Several simulations were executed to verify the effect of the adjacent nodes. As a result we found out that it affected channel responses but its effect was limited within certain degree.

CFD Analysis for the Flow Phenomena of the Narrow Channels in Plate Heat Exchanger for Intercooler (인터쿨러용 판형열교환기 내부유로의 유동현상에 관한 전산유체해석)

  • 윤천석;한승한
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.2
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    • pp.91-100
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    • 2004
  • Plate heat exchangers (PHE) have been widely used in different industrial applications, because of high heat transfer efficiency per unit volume. Basic study is performed for PHE to the application of intercooler in automobile. In order to understand the flow phenomena in the plate heat exchanger, a channel which was formed by the upper and lower plate in single plate was considered as calculation domains. Because chevrons attached on the upper plate are brazed with chevrons attached on the lower plate, the flow channel has very complex configuration. This complex geometry was analyzed by Fluent. In order to validate this methodology the proper experimental and theoretical data are collected and compared with numerical results. Finally, due to the lack of experimental values for PHE to the application of intercooler, various chevron angles and air velocities at inlet were tested in terms of physical phenomena. From this point of view, results of velocity vector, path lines, static pressure, heat flux, heat transfer coefficient, and Nusselt number are physically reasonable and accepted for the solutions. From these results, the correlations for pressure drop and Nusselt number with respect to chevron angle and Reynolds number in specific PHE are obtained for the design purpose. Thus, the methodology of the flow analysis in the full geometry of the channel was established for the predictions of performance in plate heat exchanger.

A Study on the Optimization of Deburring Process for the Micro Channel using EP-MAP Hybrid Process (전해-자기 복합 가공을 이용한 마이크로 채널 디버링공정 최적화)

  • Lee, Sung-Ho;Kwak, Jae-Seob
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.2
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    • pp.298-303
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    • 2013
  • Magnetic abrasive polishing is one of the most promising finishing methods applicable to complex surfaces. Nevertheless this process has a low efficiency when applied to very hardened materials. For this reason, EP-MAP hybrid process was developed. EP-MAP process is expected to machine complex and hardened materials. In this research, deburring process using EP-MAP hybrid process was proposed. EP-MAP deburring process is applied to micro channel, thereby it can obtain both deburring process and polishing process. EP-MAP deburring process on the micro channel was performed. Through design of experiment method, error of height in this process according to process parameter is analyzed. When the level 1 parameter A(magnetic flux density) and level 2 parameter B(electric potential), C(working gap) and level 3 parameter D(feed rate) are applied in the deburring process using EP-MAP hybrid process, it provides optimum result of EP-MAP hybrid deburring process.

A Proteomic Screen for Presynaptic Terminal N-type Calcium Channel (CaV2.2) Binding Partners

  • Khanna, Rajesh;Zougman, Alexandre;Stanley, Elise F.
    • BMB Reports
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    • v.40 no.3
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    • pp.302-314
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    • 2007
  • N type calcium channels (CaV2.2) play a key role in the gating of transmitter release at presynaptic nerve terminals. These channels are generally regarded as parts of a multimolecular complex that can modulate their open probability and ensure their location near the vesicle docking and fusion sites. However, the proteins that comprise this component remain poorly characterized. We have carried out the first open screen of presynaptic CaV2.2 complex members by an antibody-mediated capture of the channel from purified rat brain synaptosome lysate followed by mass spectroscopy. 589 unique peptides resulted in a high confidence match of 104 total proteins and 40 synaptosome proteome proteins. This screen identified several known CaV2.2 interacting proteins including syntaxin 1, VAMP, protein phosphatase 2A, $G_{o\alpha}$, G$\beta$ and spectrin and also a number of novel proteins, including clathrin, adaptin, dynamin, dynein, NSF and actin. The unexpected proteins were classified within a number of functional classes that include exocytosis, endocytosis, cytoplasmic matrix, modulators, chaperones, and cell-signaling molecules and this list was contrasted to previous reports that catalogue the synaptosome proteome. The failure to detect any postsynaptic density proteins suggests that the channel itself does not exhibit stable trans-synaptic attachments. Our results suggest that the channel is anchored to a cytoplasmic matrix related to the previously described particle web.

Microflow of dilute colloidal suspension in narrow channel of microfluidic-chip under Newtonian fluid slip condition

  • Chun Myung-Suk;Lee Tae Seok;Lee Kangtaek
    • Korea-Australia Rheology Journal
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    • v.17 no.4
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    • pp.207-215
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    • 2005
  • We present a finite difference solution for electrokinetic flow in rectangular microchannels encompassing Navier's fluid slip phenomena. The externally applied body force originated from between the nonlinear Poisson-Boltzmann field around the channel wall and the flow-induced electric field is employed in the equation of motion. The basic principle of net current conservation is applied in the ion transport. The effects of the slip length and the long-range repulsion upon the velocity profile are examined in conjunction with the friction factor. It is evident that the fluid slip counteracts the effect by the electric double layer and induces a larger flow rate. Particle streak imaging by fluorescent microscope and the data processing method developed ourselves are applied to straight channel designed to allow for flow visualization of dilute latex colloids underlying the condition of simple fluid. The reliability of the velocity profile determined by the flow imaging is justified by comparing with the finite difference solution. We recognized the behavior of fluid slip in velocity profiles at the hydrophobic surface of polydimethylsiloxane wall, from which the slip length was evaluated for different conditions.