• 한국전자파학회논문지
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• 제9권6호
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• pp.788-801
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• 1998

유성버스트 통신방식은 1000 krn 이상의 장거리 VHF NLOS 데이터 통신 시스템을 가장 경제적인 방법으 로 구현시켜 줄 수가 있다. 그러나 이 방식은 근거리 전송에서는 버스트의 지속시간이 짧아져서 도통율이 열 화함으로 본질적으로 실용에는 부적합한 것으로 알려져 있다. 이 논문에서는 유성 버스트 전송로의 근거리 특성을 해석한 후l 송/ 수신안테나의 빔 패턴이 공간의 hot-spot을 완전히 포용할 수 있도록 함으로써 버스트 의 발생빈도를 증가시키는 동시에 안테나에 유도하는 지상 잡음 전계를 효과적으로 차단함으로서 수신기의 실효 차단전압을 낮추면 시스템의 총 도통율(duty rate)은 크게 개선될 수 있음을 밝혔다. 이 해석결과를 기 초로 하여 특히 근거리 유성 버스트 경로에 적합한 안테나로서 소개구형 공동형 안테니를 개발하였다. 이 안 테니는 지하에 매설하여 사용하는데 이렇게 함으로서 수직방향의 지향성이 개선되고 지상으로부터의 잡음 혼 입이 효과적으로 차단된다. 이 안테나는 3 dB 빔 폭이 $90^{\circ}$에 달하여 앙각 8-$90^{\circ}$로서 근거리 경로의 hot-spot 를 효과적으로 조사(퍼umir뻐tel 할 수가 있는데/ 이것은 대체로 100 krn 이하의 근거리 유성 버스트 경로에 최적합한 조건이다, 지표방향으로의 지향성은 최소로 억제되어 이 방향으로부터 인공잡음의 혼입을 효과적으 로 차단하는데 재래식의 Yagi보다 평균 3 dB 이상 억제된다. 이 안테나를 수신안테나로 사용하여 100 krn 경 로에서 시험통신을 실시한 결과 동일한 조건하에서 4 소자 Ya멍 안테나를 사용한 경우에 비하여 버스트의 발 생빈도와 지속시간이 각각 10 %와 20 % 이상 증가한 것을 확인할 수 있었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.857-860
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• 1999

It is made possible a removal of the preamble for carrier recovery and symbol-timing recovery by storing a burst in memory with low overhead QPSK demodulation and this demodulation method also effects frame efficiency improved by processed synchronization performance. In this paper, we have proposed that new algorithm for arc-tangent look-up table which transform the input I, Q data by phase. This I, Q data plays an important role in demodulation and makes demodulator with low-overhead by storing a burst in memory. To evaluate proposed new algorithm and symbol-timing recovery method, function simulation and timing verification have been done by using synopsys VHDL tool.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.499-502
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• 1999

This paper presents a PCI (Peripheral Component Interconnect) controller embedded in a multimedia processor, called FLOVA (FLOating point VLIW Architecture), targeting for 3D graphics applications. Fast I/O interfaces are essential for multimedia processors which usually handle large amount of multimedia data. Therefore, in FLOVA, PCI bus is adopted for I/O interface due to fast burst transaction. However, there are several problems in implementation and verification to use burst transaction of PCI. It is difficult to handle data transaction between two units which have two different operating frequency. FLOVA has more higher operating frequency about 100MHz than that of PCI local bus and it makes lower utilization of FLOVA bus. Also, traditional simulation is not sufficient for verification of PCI functionality. In this paper, we propose buffering schemes to implement the PCI controller with wide bandwidth and high bus utilization. Also, this paper shows how to verify the PCI controller using real PCI bus environments before its fabrication.

• 천문학회보
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• 제38권1호
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• pp.69.2-69.2
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• 2013

The direct detection of gravitational wave has a very important meaning as a basis for verification of the theory of relativity. Several laser interferometer detectors have attempted to detect GW directly (e.g. LIGO, VIRGO), but positional accuracy of GW detector is too wide (about 10~100sq deg) to find which objects emit GW. One of the main sources of GW is gamma-ray burst which can be detected even in electromagnetic wave. Then to verify Gamma-ray burst object as a GW source, we proceed EM follow-up observation with wide field of view. A first program initiating EM follow-ups to possible transients GW events has been developed and exercised by LIGO and VIRGO community in association with several partners. Using QUEST optical data, we tested the method of cross-convolution recommended by EM follow-up community. We will describe the results of that test.

• 한국IT서비스학회지
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• 제9권2호
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• pp.151-161
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• 2010

Recently, as the era of ubiquitous has arrived, an infrastructure for the short-distance wireless communication has been extended socially, and thus a variety of services are being proposed. The Multimedia Contents Delivery System using the ZigBee, in particular, has an important stance in enlargement of a variety of services in the aspect of individual-oriented service support though Wireless Personal Area Network (WPAN). Nonetheless, the ZigBee, or the IEEE 802.15.4 Standard, has many restrictions on the Multimedia Contents Delivery System due to the low data transport rate. In order to improve the ZigBee which presents a limit on the transport rate at the IEEE 802.15.4 Standard, this thesis has designed the burst mode which is a method of transmitting a certain amount of data in block units at a high speed without any stoppage until the completion of the transmission. Also, to provide a Multimedia Contents Delivery Service with an application of the normal data transmission mode, it improved the transmission performance of the ZigBee. In addition, for the Multimedia Contents Delivery Service under the ubiquitous environment, it designed and implemented a broadcasting Multimedia Contents Delivery System based on the ZigBee to conduct a comparative analysis on the data transmission performance according to the transmission method.

• Nuclear Engineering and Technology
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• 제55권1호
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• pp.100-108
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• 2023

In this study, a neural network model inspired by a one-dimensional convolution U-net is developed to automatically accelerate edge localized mode (ELM) detection from big diagnostic data of fusion devices and increase the detection accuracy regardless of the hyperparameter setting. This model recognizes the input signal patterns and overcomes the problems of existing detection algorithms, such as the prominence algorithm and those of differential methods with high sensitivity for the threshold and signal intensity. To train the model, 10 sets of discharge radiation data from the KSTAR are used and sliced into 11091 inputs of length 12 ms, of which 20% are used for validation. According to the receiver operating characteristic curves, our model shows a positive prediction rate and a true prediction rate of approximately 90% each, which is comparable to the best detection performance afforded by other algorithms using their optimized hyperparameters. The accurate and automatic ELM-burst detection methodology used in our model can be beneficial for determining plasma properties, such as the ELM frequency from big data measured in multiple experiments using machines from the KSTAR device and ITER. Additionally, it is applicable to feature detection in the time-series data of other engineering fields.

• 한국통신학회:학술대회논문집
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• 한국통신학회 1990년도 추계종합학술발표회논문집
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• pp.131-134
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• 1990

• Journal of Astronomy and Space Sciences
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• 제23권3호
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• pp.167-176
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• 2006

We investigate the correlation between the peak energy and the burst duration using available long GRB data with known redshift, whose circumburst medium type has been suggested via afterglow light curve modeling. We find that the peak energy and the burst duration of the observed GRBs are correlated both in the observer frame and in the GRB rest frame. For our total sample we obtain, for instance, the Spearman rank-order correlation values ${\sim}0.75\;and\;{\sim}0.65$ with the chance probabilities $P=1.0{\times}10^{-3}\;and\;P=6.0{\times}10^{-3}$ in the observer frame and in the GRB rest frame, respectively. We note that taking the effects of the expanding universe into account reduces the value a bit. We further attempt to separate our GRB sample into the 'ISM' GRBs and the 'WIND' GRBs according to environment models inferred from the afterglow light curves and apply statistical tests, as one may expect that clues on the progenitor of GRBs can be deduced directly from prompt emission properties other than from the ambient environment surrounding GRBs. We find that two subsamples of GRBs show different correlation coefficients. That is, the Spearman rank-order correlation are ${\sim}0.65\;and\;{\sim}0.57$ for the 'ISM' GRBs and 'WIND' GRBs, respectively, after taking the effects of the expanding universe into account. It is not yet, however, statistically very much significant that the GRBS in two types of circumburst media show statistically characteristic behaviors, from which one may conclude that all the long bursts are not originated from a single progenitor population. A larger size of data is required to increase the statistical significance.

• 한국건설관리학회논문집
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• 제24권3호
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• pp.42-51
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• 2023

겨울철 동파는 물사용 불가, 2차 피해 및 계량기 교체비용 발생 등 많은 사회적 비용을 발생시키고 있다. 정부에서는 지방상수도 시설의 현대화를 위해 많은 노력을 기울이고 있으며, 특히나 전국적으로 SWM 사업을 추진 중에 있다. 본 연구에서는 수용가의 최접점에 설치되는 스마트 미터링에 착안하여 기존의 대기온도가 아닌 계량기 함내 온도를 기반으로 하는 새로운 동파위험 알림 정보서비스를 계획하였다. 또한 본 연구에서는 전국적으로 설치된 스마트미터의 수량적인 한계를 극복하기 위하여, 온도센서로부터 취득된 자료들을 바탕으로 물리적인 온도센서가 없는 지역의 온도를 예측하는 인공지능 기반의 온도예측 모델을 개발하였고, 최적화 과정을 통해 전국을 대상으로 하는 수도계량기 동파위험 정보서비스(안)을 구상하였다.

• 한국군사과학기술학회지
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• 제6권4호
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• pp.22-28
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• 2003

In the conventional weapon system, such as gun and small arms, it Is a general trend that for maximization of its performance and enhancement of its effectiveness, the firing control system(FCS) is developed and applied with the guns and small arms in the world. The FCS of the small arms for infantry man is composed of a few of sensors for acquisition of input data of FCS, such as range measurement, position sensing of weapon, temperature, etc., computer, displayer and power pack, and also the air burst munition is developed in parallel for the maximization of FCS's effectiveness. Since the flight time setting fuze for the air burst munition is adapted for next me, the measuring device of the muzzle velocity is needed to overcome the variation of muzzle velocity due to producing procedures and the differences of the using temperatures and so maintain the burst position accuracy This paper contained the technical information on the development of the measuring device of muzzle velocity, which designed in compact & light weight configuration with reliability and accuracy.