• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2013년도 추계학술발표대회
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• pp.259-261
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• 2013

금융 IT와 같은 분야에서는 빅데이터의 큰 특징 중 하나인 Velocity의 개선이 가장 큰 문제이다. 이는 산업의 특성상 승자가 시장을 독식하는 구조로 0.1 초라도 빠른 시스템 속도를 확보하면 시장 경쟁력이 매우 크기 때문이다. 비단 금융 IT 뿐만 아니라 다른 산업들도 최근 보다 빠른 속도의 데이터 처리에 매우 민감하게 반응하는 환경으로 변화하고 있으므로 이에 대한 솔루션이 필요하며 본 연구에서는 폭증스트림의 고속처리를 위한 Low-Latency에 대한 다양한 실험과 환경 구축을 통해 빅데이터의 Velocity 문제를 해결할 수 있는 방안을 제시한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권7호
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• pp.3309-3328
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• 2017

The application of Internet of Things (IoT) in the next generation cellular networks imposes a new characteristic on the data traffic, where a massive number of small packets need to be transmitted. In addition, some emerging IoT-based emergency services require a real-time data delivery within a few milliseconds, referring to as ultra-low latency transmission. However, current techniques cannot provide such a low latency in combination with a mice-flow traffic. In this paper, we propose a dynamic resource reservation schema based on an air-interface slicing scheme in the context of a massive number of sensors with emergency flows. The proposed schema can achieve an air-interface latency of a few milliseconds by means of allowing emergency flows to be transported through a dedicated radio connection with guaranteed network resources. In order to schedule the delay-sensitive flows immediately, dynamic resource updating, silence-probability based collision avoidance, and window-based re-transmission are introduced to combine with the frame-slotted Aloha protocol. To evaluate performance of the proposed schema, a probabilistic model is provided to derive the analytical results, which are compared with the numerical results from Monte-Carlo simulations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 G
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• pp.3221-3223
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• 1999

OAEs are low-level sounds produced by cochlea as part of the normal hearing process. OAEs can be measured with a microphone placed in the outer ear-cannel. We can diagnose cochlea's condition by using OAEs. To diagonose it's condition, however, is difficult by reason of OAEs' tiny. Thus, It need to a method using latency which essential diagnosing a time-element of OAEs. This study proposes a latency detection algorithm using 7-QMF for more effective detection of latency, 7-QMF designed by wavelet theory can process signal without a losses of information. The latency-detector based on 7-QMF is superior to former method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2483-2485
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• 1998

Change in lantency of otoacoustic emission(OAE) may indicate clinically and diagnostically important change in the status of the nervous system. A low signal-to-noise ratio of OAE signal makes it difficult to estimate small, transient, time-varing changes in latency. we present an adaptive algorithm that estimates small latency change value even when OAE signal amplitudes are time-varing.

• Journal of Communications and Networks
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• 제17권6호
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• pp.582-591
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• 2015

A massive distributed storage system is the foundation for big data operations. Access latency performance is a key metric in distributed storage systems since it greatly impacts user experience while existing codes mainly focus on improving performance such as storage overhead and repair cost. By generating parity nodes from parity nodes, in this paper we design new XOR-based erasure codes hierarchical tree structure code (HTSC) and high failure tolerant HTSC (FH HTSC) to reduce access latency in distributed storage systems. By comparing with other popular and representative codes, we show that, under the same repair cost, HTSC and FH HTSC codes can reduce access latency while maintaining favorable performance in other metrics. In particular, under the same repair cost, FH HTSC can achieve lower access latency, higher or equal failure tolerance and lower computation cost compared with the representative codes while enjoying similar storage overhead. Accordingly, FH HTSC is a superior choice for applications requiring low access latency and outstanding failure tolerance capability at the same time.

• 대한통합의학회지
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• 제8권2호
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• pp.131-138
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• 2020

Purpose : The purpose of this study was to investigate the effects of the frequency band pass filter on the P300 event-related potential in the working memory. Methods : The subjects were 20 women in their 20s who applied for participation in the experiment. Event-related potentials (ERPs) were elicited using 3-back tasks for the working memory, and were recorded from Fz, Cz, and Pz scalp electrodes. The high-pass filters were set to 0.01, 0.1, and 0.3 Hz for analysis purposes, and the low-pass filters were set to 30 and 15 Hz. The 3-back task was presented for a total of 100 times, among which 30 times were designated for the target stimulation (a matched number) and 70 times for the non-target stimulation (an unmatched number). The temporal interval between each stimulation was set at 1 second, while each time duration was randomly presented between 2 to 4 seconds. ERP were analyzed for the P300 recorded from Fz, Pz and Cz scalp electrodes. Results : Latency and amplitude had no significant interaction effects in both the high- and low-pass filters. For the main effects, the latency and amplitude of the P300 event-related potential had no significant difference in the high-pass filters, but the latency had a significant difference in the low-pass filter of Fz, and the amplitude had a significant difference in the low-pass filter of Pz. Conclusion : The results of this study showed that the less than 0.3 Hz high filters had no effects on the differences between the latency and amplitude of the P300 event-related potential in the working memory. The 30Hz low-pass filter, however, was found to be useful for recording the P300 event-related potential in the working memory.

• 한국정보과학회논문지:정보통신
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• 제35권4호
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• pp.326-336
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• 2008

무선 센서 네트워크의 연구는 이벤트 기반과 주기적 모니터링 기반이라는 두 가지 응용의 형태에 맞추어 진행되었다. 두 가지 응용의 핵심적인 요구 사항은 다르지만 안정적인 운용을 위해 공통적으로 낮은 전송 지연의 요구가 존재한다. 하지만 기존의 무선 센서 네트워크의 프로토콜은 에너지 효율성을 중심으로 연구가 진행되었기 때문에 전송 지연에 대한 고려가 부족하였다. 본 논문에서는 무선 센서 네트워크의 MAC 프로토콜인 RA-MAC(RTS Aggregation-Media Access Control) 프로토콜을 제안하였다. RA-MAC 프로토콜은 새로운 채널 접근 기법 및 RTS Aggregation 기법에 의해 에너지 효율성과 낮은 전송 지연을 이룰 수 있고 수신 노드의 전송 스케줄링에 의해 이벤트 기반과 주기적 모니터링 기반 응용의 요구 사항을 동시에 만족시킬 수 있다. 실험을 통해 RA-MAC 프로토콜은 기존에 제안된 에너지 효율적인 MAC 프로토콜과 비슷한 에너지 효율을 보이면서 좀 더 낮은 전송 지연을 이루고 전송률을 향상시킬 수 있음을 확인하였다.

• 한국통신학회논문지
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• 제30권2A호
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• pp.20-25
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• 2005

본 논문에서는 trace-back 동작 없이 디코딩이 가능한 변형된 레지스터 교환 (MRE) 방식을 블록 디코딩에 적용하여 전송 속도를 높이고 latency를 줄이는 비터비 디코딩 방식을 제안하였다. 변형된 레지스터 교환 방식을 블록 디코딩에 적용함으로써 디코딩 블록의 시작 상태를 결정하기 위해 필요한 동작 사이클을 줄여, 블록 디코딩을 사용하는 기존의 비터비 디코더보다 더 적은 latency를 가지게 되었다. 뿐만 아니라, 메모리를 더 효율적으로 사용할 수 있으면서 하드웨어의 구현에 있어서도 복잡도가 더 감소하게 된다. 또한 시작 상태를 결정하기 위해 필요한 trace-back 동작을 없애고 메모리를 줄여 이에 따른 전력 소모를 줄이는 저전력 동작이 가능하다. 제안된 방식은 같은 하드웨어 복잡도로도 메모리의 감소 또는 latency의 감소에 중점을 둔 설계가 가능하다. 또한, 몇 가지 디자인 파라미터를 변경하여 합성 단계에서 하드웨어 복잡도와 전송 속도를 Dade-off 할 수 있도록 스케일러블한 구조로 설계하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 학술대회 논문집 정보 및 제어부문
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• pp.117-118
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• 2008

The low latency encoder for high data rate duo-binary turbo codes with tail biting trellises is considered. Encoder hardware architecture is proposed using inherent encoding property of duo-binary turbo codes. And we showed that half of execution time as well as the energy can be reduced with the proposed architecture.

• 전자통신동향분석
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• 제35권5호
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• pp.57-68
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• 2020

This paper reviews the recent trends in optical access technologies and their future directions. As the number of hyper-connected, ultra-low-latency, and hyper-realistic services increases, the wireless path has become shorter and the optical access network has become deeply penetrated into the end user. The optical access network continues to evolve through endless innovation via high-speed, ultra-low-latency, and abstraction/virtualization technologies.