• Progress in Superconductivity
• /
• 제2권1호
• /
• pp.20-26
• /
• 2000

A 40-channel superconducting quantum interference device (SQUID) system was constructed for measuring neuromagnetic fields. Main features of the system are the use of double relaxation oscillation SQUIDs (DROSs), and planar gradiometers measuring magnetic field components tangential to the head surface. The DROSs with high flux-to-voltage transfers enabled direct readout of the SQUID output by room-temperature dc preamplifiers and simple flux-locked loop circuits could be used for SQUID operation. The pickup coil is an integrated first-order planar gradiometer with a baseline of 40 mm. Average noise level of the 40 channels is around 1.2 $fT/cm/{\surd}Hz$ at 100 Hz, corresponding to a field noise of 5 $fT/{\surd}Hz$, operated inside a magnetically shielded room. The SQUID insert was designed to have low thermal load, minimizing the loss of liquid helium. The constructed system was applied to measure auditory-evoked neuromagnetic fields.

• 한국통신학회논문지
• /
• 제27권8B호
• /
• pp.780-786
• /
• 2002

본 논문에서는 음성과 데이터 패킷을 전송하는 WCDMA의 CPCH에서 대기시간의 개념을 적용하여 채널 접속을 제어하는 시스템을 제안한다. 기존의 CA 방식은 모든 CPCH 채널코드가 할당된 상태일 때 VT 및 DT가 채널에 접속하면 노드 B가 이를 차단하게 된다. 그러나 본 논문에서 제안하는 대기시간을 갖는 CA 방식은 모든 CPCH 채널 코드가 할당된 상태라도 접속한 VT 및 DT가 대기시간을 갖고 채널의 할당을 기다릴 수 있기 때문에 과다한 접속을 줄일 수 있다. 따라서 본 논문에서 제안한 대기시간을 갖는 CPCH 채널 접속 방식이 기존의 시스템에 비해 차단 확률과 접속 횟수, 시스템 처리량에서 우수한 성능을 갖는다.

• 한국통신학회논문지
• /
• 제18권2호
• /
• pp.250-260
• /
• 1993

PRMA(Packet Reservation Multiple Access) 프로토콜은 연집 트래픽 특성을 갖는 불특정다수의 단말기들이 공유채널을 엑세스하기 위해 서로 경쟁하는 환경하에서 음성 트래픽과 데이터 트래픽을 집적하여 서비스하는데 매우 효율적인 것으로 잘 알려져 있다. 그러나 PRMA 프로토콜에서는 부하가 커지면 예약채널의 용량이 영(Zero)으로 축소될 수도 있으므로 시스템이 불안정해지고 고부하 상태에서는 제대로 동작할 수 없다. 본 논문에서는 이러한 PRMA의 단점을 보완할 수 있으며 보다 안정되게 동작하는 음성/데이타 직접 PRMA 프로토콜을 제안하고, 프레임 및 슬롯구조를 제시하여, 제안된 프로토콜의 성능을 컴퓨터 시뮬레이션을 통하여 분석해 보았다. 시뮬레이션 결과, 기존의 방식에 비해 제안된 프로토콜이 보다 효율적으로 음성과 데이타를 집적할 수 있으며, 고부하 상태에서도 보다 안정되게 동작함을 알 수 있었다.

• Agricultural and Biosystems Engineering
• /
• 제1권2호
• /
• pp.106-110
• /
• 2000

An integrated on-line inspection system was constructed with seven cameras, half mirrors to split images. 720 nm and 970 nm band pass filters, illumination chamber having several tungsten-halogen lamps, one main computer, one color frame grabber, two 4-channel multiplexors, and flat plate conveyer, etc. A total of seven images, that is, one color image form the top of an apple and two B/W images from each side (top, right and left) could be captured and displayed on a computer monitor through the multiplexor. One of the two B/W images captured from each side is 720nm filtered image and the other is 970 nm. With this system an on-line grading software was developed to evaluate appearance quality. On-line test results with Fuji apples that were manually fed on the conveyer showed that grading accuracies of the color, defect and shape were 95.3%, 86% and 88.6%, respectively. Grading time was 0.35 second per apple on an average. Therefore, this on-line grading system could be used for inspection of the final products produced from an apple sorting system.

• 물과 미래
• /
• 제29권2호
• /
• pp.199-207
• /
• 1996

온배수의 거동해석에 $\kappa-\imath$ 난류모델의 사용성 평가를 위해 수심적분 2차원 수치모형을 개발하였다. 개발된 모형은 간단한 단면을 갖는 개수로 정상류의 경우에 적용하였으며, 기존의 실험결과와 비교적 잘 일치하였다. 온수의 재순환, 재부착 및 초과온도 상승분포의 적절한 모의해석은 $\kappa-\imath$ 난류모델에 의한 적절한 난류 점성 및 확산계수의 산정때문이라 생각된다. 예측의 정확성을 위하여 부력생성항의 도입, Source/Sink 항의 수정 및 그에 따른 적절한 난류 상수의 규명이 필요하다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권5호
• /
• pp.2433-2452
• /
• 2017

Recently, the pipeline-forwarding has been proposed as a new technique to resolve the end-to-end latency problem of the duty-cycle MAC protocols in Wireless Sensor Networks (WSNs). Some protocols based on this technique such as PMAC and PRI-MAC have shown an improvement not only in terms of reducing end-to-end latency but also in terms of reducing power consumption. In these protocols, however, the sensor nodes still waste a significant amount of energy for unnecessary idle listening during contention period of upstream nodes to check the channel activity. This paper proposes a new pipeline-forwarding duty-cycle MAC protocol, named RP-MAC (Reduced Pipelined duty-cycle MAC), which tries to reduce the waste of energy. By taking advantage of ACK mechanism and shortening the handshaking procedure, RP-MAC minimizes the time for checking the channel and therefore reduces the energy consumption due to unnecessary idle listening. When comparing RP-MAC with the existing solution PRI-MAC and RMAC, our QualNet-based simulation results show a significant improvement in term of energy consumption.

• Nuclear Engineering and Technology
• /
• 제23권4호
• /
• pp.401-409
• /
• 1991

본 연구에서는 길이 방향의 핀이 달린 봉 다발의 난류 마찰계수를 예측할 수 있는 해석적 모델이 개발되었다. 현재 KMRR의 연료봉으로 핀이 달린 봉다발이 고려되고 있다. 본 모델에서는“Law of the Wall”이 전체 수로에 적용 가능하다고 가정하였다. 전체 수로를 작은 요소 수로와 핀 간 수로로 나누고 각 요소 수로마다“Law of the Wall”속도 분포 곡선을 적분하여 난류 마찰계수를 예측할 수 있는 해석적 방정식을 얻는다. 이 방법을 KMRR 연료봉에 적용한 결과 6핀 실험결과는 잘 예측하고 8핀 실험 결과는 15％ 정도 높게 예측하였다.

• 한국전기전자재료학회논문지
• /
• 제29권12호
• /
• pp.750-758
• /
• 2016

For the channel doping of shallow junction and retrograde well formation in CMOS, indium can be implanted in silicon. The retrograde doping profiles can serve the needs of channel engineering in deep MOS devices for punch-through suppression and threshold voltage control. Indium is heavier element than B, $BF_2$ and Ga ions. It also has low coefficient of diffusion at high temperatures. Indium ions can be cause the erode of wafer surface during the implantation process due to sputtering. For the ultra shallow junction, indium ions can be implanted for p-doping in silicon. UT-MARLOWE and SRIM as Monte carlo ion-implant models have been developed for indium implantation into single crystal and amorphous silicon, respectively. An analytical tool was used to carry out for the annealing process from the extracted simulation data. For the 1D (one-dimensional) and 2D (two-dimensional) diffused profiles, the analytical model is also developed a simulation program with $C^{{+}{+}}$ code. It is very useful to simulate the indium profiles in implanted and annealed silicon autonomously. The fundamental ion-solid interactions and sputtering effects of ion implantation are discussed and explained using SRIM and T-dyn programs. The exact control of indium doping profiles can be suggested as a future technology for the extreme shallow junction in the fabrication process of integrated circuits.

• 대한기계학회논문집
• /
• 제16권8호
• /
• pp.1545-1551
• /
• 1992

본 연구에서는 벽면의 법칙(law of the wall)을 이용하여 봉다발의 난류 마찰 계수를 예측하는 간단한 방법이 제안되었다. 이 방법은 전체 유로를 요소 유로로 나 누고 각 요소유로에 벽면의 법칙을 적용하여 마찰 계수를 구한다.이 방법을 사용 하면 마찰 계수가 간단한 산술식의 형태로 나타나므로 복잡한 형상의 봉다발의 마찰 계수도 손쉽게 구할 수 있다.

• 유통과학연구
• /
• 제19권1호
• /
• pp.5-15
• /
• 2021

Purpose: This study explores the types of relational benefits that generate loyalty to room-sharing services among Chinese customers based on the relationship marketing literature. The study also examines the moderating effect of alternative attractiveness on this relationship. Research design, data and methodology: Based on research hypotheses, questionnaires with items measuring the proposed constructs in three dimensions, including relational benefits, alternative attractiveness, and customer loyalty, were designed to test the hypotheses. Data were collected via an online questionnaire of 220 room-sharing service customers in China. Results: Results verify the effects of relational benefits on customers' loyalty to room-sharing services and the mediating effect of alternative attractiveness. More specifically, confidence, social, and safety benefits positively affect customer loyalty to room-sharing services, and alternative attractiveness moderates only the effect of social benefits. Conclusions: The results suggest that room-sharing service providers should concentrate on providing confidence, social, and safety benefits to maintain long-term relationships with customers. This study also provides practical implication for building relationships between channel members in service distribution channels. The study concludes that without customer relationships marketing for managing collaborative and social communication channels, the entire distribution channel might lose out eventually.