• 전자공학회논문지
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• 제51권1호
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• pp.71-76
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• 2014

본 논문에서는 새로운 구조의 단일채널 모노펄스수신기 및 동작 절차를 제시하였다. 또한, 제안한 수신기와 일반적인 3채널 모노펄스수신기를 비교 분석 하였으며, 시뮬레이션을 통해 제안한 수신기에서 획득되는 모노펄스기울기가 3채널 모노펄스수신기와 동일함을 검증하였다. 제안한 수신기는 3채널의 수신기 및 신호처리기를 요구하는 일반적인 3채널 모노펄스수신기에 비해 1채널의 수신기를 요구하고 신호처리가 필요 없으므로 수신부 및 처리부의 구조가 간단하고, 크기, 무게, 비용, 소모전력 측면에서 절감 등의 이점을 갖고 있다. 또한, 제안한 모노펄스수신기는 수신기의 검출기에 의해 측정한 합 및 차 신호의 동위상 결합전력에서 역위상 결합전력의 차이를 이용하여 모노펄스 추적을 수행하므로 모노펄스 추적절차가 용이하다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권2호
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• pp.628-646
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• 2016

This paper proposes a novel channel assignment scheme that is based on finite projective plane (FPP) theory. The proposed scheme involves using a Markov chain model to allocate N channels to N users through intermixed channel group arrangements, particularly when channel resources are idle because of inefficient use. The intermixed FPP-based channel group arrangements successfully related Markov chain modeling to punch through ratio formulations proposed in this study, ensuring fair resource use among users. The simulation results for the proposed FPP scheme clearly revealed that the defined throughput increased, particularly under light traffic load conditions. Nevertheless, if the proposed scheme is combined with successive interference cancellation techniques, considerably higher throughput is predicted, even under heavy traffic load conditions.

• The Korean Journal of Pain
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• 제24권3호
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• pp.131-136
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• 2011

Background: Pregabalin is an anticonvulsant and analgesic agent that interacts selectively with the voltage-sensitive-$Ca^{2+}$-channel alpha-2-delta subunit. The aim of this study was to evaluate whether the analgesic action of intrathecal (IT) pregabalin is associated with KATP channels in the rat formalin test. Methods: IT PE-10 catheters were implanted in male Sprague-Dawley rats (250.300 g) under inhalation anesthesia using enflurane. Nociceptive behavior was defined as the number of hind paw flinches during 60 min after formalin injection. Ten min before formalin injection, IT drug treatments were divided into 3 groups: normal saline (NS) $20\;{\mu}l$ (CON group); pregabalin 0.3, 1, 3 and $10\;{\mu}g$ in NS $10\;{\mu}l$ (PGB group); glibenclamide $100\;{\mu}g$ in DMSO $5\;{\mu}l$ with pregabalin 0.3, 1, 3 and $10\;{\mu}g$ in NS $5\;{\mu}l$ (GBC group). All the drugs were flushed with NS $10\;{\mu}l$. Immunohistochemistry for the $K_{ATP}$ channel was done with a different set of rats divided into naive, NS and PGB groups. Results: IT pregabalin dose-dependently decreased the flinching number only in phase 2 of formalin test. The log dose response curve of the GBC group shifted to the right with respect to that of the PGB group. Immunohistochemistry for the $K_{ATP}$ channel expression on the spinal cord dorsal horn showed no difference among the groups 1 hr after the formalin test. Conclusions: The antinociceptive effect of pregabalin in the rat formalin test was associated with the activation of the $K_{ATP}$ channel. However, pregabalin did not induce $K_{ATP}$ channel expression in the spinal cord dorsal horn.

• Korean Journal of Acupuncture
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• 제28권4호
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• pp.41-48
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• 2011

Objectives : This study aimed to explore the passive multi-channel time series analysis method by measuring bio-potentials of acupuncture point and the peripheral region Methods : Bio-potential was measured at ST36 and the peripherical region of ST36 of 5 healthy volunteers at three times. The diagram of the potential changes over time were smoothed by moving average method and similarities of ST36 and the other points were calculated. Results : In the normal weight group, bio-potential similarity tended to decrease in proportion to the distance from the acupuncture point. In the obesity group, bio-potential similarity appeared in a very wide area. Bio-potential similarity had positive correlation with BMI value. Conclusions : The passive multi-channel time series analysis method showed the possibility be appropriate for the electrical characteristics study of meridians.

• Journal of Communications and Networks
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• 제12권5호
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• pp.411-432
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• 2010

We consider three different secure broadcasting scenarios: i) Broadcast channels with common and confidential messages (BCC), ii) multi-receiver wiretap channels with public and confidential messages, and iii) compound wiretap channels. The BCC is a broadcast channel with two users, where in addition to the common message sent to both users, a private message, which needs to be kept hidden as much as possible from the other user, is sent to each user. In this model, each user treats the other user as an eavesdropper. The multi-receiver wiretap channel is a broadcast channel with two legitimate users and an external eavesdropper, where the transmitter sends a pair of public and confidential messages to each legitimate user. Although there is no secrecy concern about the public messages, the confidential messages need to be kept perfectly secret from the eavesdropper. The compound wiretap channel is a compound broadcast channel with a group of legitimate users and a group of eavesdroppers. In this model, the transmitter sends a common confidential message to the legitimate users, and this confidential message needs to be kept perfectly secret from all eavesdroppers. In this paper, we provide a survey of the existing information-theoretic results for these three forms of secure broadcasting problems, with a closer look at the Gaussian multiple-input multiple-output (MIMO) channel models. We also present the existing results for the more general discrete memoryless channel models, as they are often the first step in obtaining the capacity results for the corresponding Gaussian MIMO channel models.

• 방송공학회논문지
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• 제8권2호
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• pp.163-171
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• 2003

고정 및 이동수신환경에서 결합 소스/채널 부호화 기법을 MPEG-4(Moving picture Experts Group) 비디오 전송에 적용하여 대역폭 사용 효율을 높이는 방안에 대하여 논하였다. 채널환경은 랜덤잡음환경과 이동수신환경을 고려하였다. 소스부호화기는 MPEG-4 비디오, 채널부호화기는 RCPC(Rate Compatible Punctured Convolution) 그리고 변조방식은 QPSK(Quadrature Phase Shift Keying)를 적용하였다. 이 논문에서는 여러가지 채널상태(Es/No)에 따른 율-왜곡특성에 대해 분석하여 소스비트율과 채널부호율 간에 최적의 상충점(Trade-off point)을 결정하였고, 결합 소스/채널 부호화 기법과 일반적인 고정부호율 전송기법을 비교하여 결합 소스/채널부호화의 효율성을 보였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권2호
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• pp.583-599
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• 2015

We apply the Bayesian matching pursuit (BMP) algorithm to the estimation of time-frequency selective channels in orthogonal frequency division multiplexing (OFDM) systems. By exploiting prior statistics and sparse characteristics of propagation channels, the Bayesian method provides a more accurate and efficient detection of the channel status information (CSI) than do conventional sparse channel estimation methods that are based on compressive sensing (CS) technologies. Using a reasonable approximation of the system model and a skillfully designed pilot arrangement, the proposed estimation scheme is able to address the Doppler-induced inter-carrier interference (ICI) with a relatively low complexity. Moreover, to further reduce the computational cost of the channel estimation, we make some modifications to the BMP algorithm. The modified algorithm can make good use of the group-sparse structure of doubly selective channels and thus reconstruct the CSI more efficiently than does the original BMP algorithm, which treats the sparse signals in the conventional manner and ignores the specific structure of their sparsity patterns. Numerical results demonstrate that the proposed Bayesian estimation has a good performance over rapidly time-varying channels.

• 한국수소및신에너지학회논문집
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• 제30권5호
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• pp.448-454
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• 2019

This paper presents a high-efficiency design technique for developing the serialized models of a single-channel pump based on the diameter, flow rate and head as the main performance parameters. The variation in pump performance by changing of the single-channel pump geometry was predicted based on computational fluid dynamics (CFD). Numerical analysis was conducted by solving three-dimensional steady Reynolds-averaged Navier-Stokes equations with the shear stress transport (SST) turbulence model. The tendencies of the hydraulic performance depending on the pump geometry scale were analyzed with the fixed rotational speed. These performances were expressed and evaluated as the functionalization for designing the serialized models of a single-channel pump in this work.

• 전자공학회논문지
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• 제52권12호
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• pp.3-9
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• 2015

본 논문에서는 새로운 구조의 모노펄스수신기 동작 절차를 제시하고, 설계 및 제작을 통해 모노펄스 기울기 및 추적정확도 등의 성능을 분석하였다. 제작된 모노펄스수신기의 기울기와 3채널 모노펄스수신기의 기울기가 동일함을 검증하였으며, +0.7~-0.7 범위에서 0.1 RMS 이하의 추적정확도 성능을 확인하였다. 제작된 모노펄스수신기를 적용한 모노펄스시스템은 3채널의 수신기 및 신호처리기를 요구하는 일반적인 3채널 모노펄스시스템에 비해 1채널의 수신기를 요구하고 신호처리가 필요 없으므로 수신부 및 처리부의 구조가 간단하며, 크기, 무게, 비용, 소모전력 측면에서 절감 등의 이점을 갖고 있다. 또한, 수신기의 디텍터에 의해 측정한 합 및 차신호의 동위상 결합전력에서 역위상 결합전력의 차이를 이용하여 모노펄스 추적을 수행하므로 모노펄스 추적절차가 용이하다.

• 대한전자공학회논문지TC
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• 제40권10호
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• pp.51-58
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• 2003

본 논문에서는 광 버스트 스위칭 네트워크의 코어 노드에서 네트워크 자원을 보다 효율적으로 이용할 수 있는 새로운 스케줄링 방식인 그룹 스케줄링 방식을 제안하였다. 이 방식은 헤더 패킷들을 수집한 후 해당 스케줄링 창에 속하는 버스트들의 도착 시간 및 길이 정보를 이용하여 작성된 구간 그래프로부터 최대 안정집합을 선택하여 버스트들을 스케줄링하는 방식이다. 다수 개의 버스트들을 동시에 스케줄링하기 때문에 기존의 일대일 스케줄링 방식들 보다 버스트 손실 확률을 감소시킬 수 있으며, 채널 이용률도 높일 수 있다. 버스트의 길이가 지수 분포를 갖는 경우와 일정한 길이를 갖는 경우에 대해 전산 모의 실험으로 LAUC-VF 방식인 즉시 스케줄링 방식과 비교 평가한 결과 버스트 손실 확률과 채널 이용률 모두 그룹 스케줄링방식이 즉시 스케줄링 방식보다 우수함을 확인하였다.