• 전기전자학회논문지
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• 제12권2호
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• pp.81-86
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• 2008

In wireless communication system using 2.4GHz radio link, data rate varies with time due to interferences, which causes the performance degradation. Therefore, effective transmission methods are required to obtain better performance according to varying data rate. This paper proposes a novel method that increases the data rate, as well as the influence of different loop-filter bandwidths on the performance of the PLL. Experimental results show that the proposed method is effective because it can achieve higher throughput in various data rate.

• 산업공학
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• 제9권3호
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• pp.225-235
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• 1996

The SECS Ⅰ and Ⅱ Protocol has been widely used for the TFT LCD and semiconductor industry. This paper shows how the SECS protocol is implemented for data communications between the Host (CAM) and the TFT LCD equipments. In addition, this study introduces a way to apply the SECS protocol to the manufacturing systems control. It provides better throughput in terms of production and faster control of the automated TFT LCD manufacturing system by way of shortcut and distribution of control and data communications. The SECS protocol is successfully used for the control of the real TFT LCD manufacturing system.

• ETRI Journal
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• 제37권2호
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• pp.359-368
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• 2015

In this paper, we investigate the capture effect through experiments conducted with Iris nodes equipped with AT86RF230 radio transceivers. It is shown that the first arriving packet in a collision can capture the radio channel for equal power transmissions and may be decoded depending on the amount of overlap. A new 3-packet-capture scenario is introduced and implemented. To be able to understand the impact of capture on the throughput performance of wireless sensor networks, we present an analysis of the capture coefficient using our practical results. For real-world implementations, the throughput of pure ALOHA considering a finite number of users is presented in analytical form. The capture coefficient is then applied to pure ALOHA as a case study. Using analytical and practical implementations of the capture effect on ALOHA, a very good match in channel throughput performance enhancement is demonstrated over the non-capture effect case. TinyOS-2.x is used to program the nodes and to observe data exchange on a computer through a base station.

• 농업과학연구
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• 제45권3호
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• pp.317-323
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• 2018

The demand for crop production is increasingly becoming steeper due to the rapid population growth. As a result, breeding cycles should be faster than ever before. However, the current breeding methods cannot meet this requirement because traditional phenotyping methods lag far behind even though genotyping methods have been drastically developed with the advent of next-generation sequencing technology over a short period of time. Consequently, phenotyping has become a bottleneck in large-scale genomics-based plant breeding studies. Recently, however, phenomics, a new discipline involving the characterization of a full set of phenotypes in a given species, has emerged as an alternative technology to come up with exponentially increasing genomic data in plant breeding programs. There are many advantages for using new technologies in phenomics. Yet, the necessity of diverse man power and huge funding for cutting-edge equipment prevent many researchers who are interested in this area from adopting this new technique in their research programs. Currently, only a limited number of groups mostly in developed countries have initiated phenomic studies using high throughput methods. In this short article, we describe the strategies to compete with those advanced groups using limited resources in developing countries, followed by a brief introduction of high throughput phenotyping.

• 한국군사과학기술학회지
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• 제14권5호
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• pp.880-887
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• 2011

The Wireless Mesh Network(WMN) technology is able to provide an infrastructure for isolated islands, in which it is difficult to install cables or wide area such as battlefield. Therefore, WMN is frequently used to satisfy needs for internet connection and active studies and research on them are in progress. However, as a result of increase in number of hops under hop-by-hop communication environment has caused a significant decrease in throughput and an increase in delay. Considering the heavy traffic of real-time data, such as voice or moving pictures to adaptive WMN, in a military environment. Such phenomenon might cause an issue in fairness index. In order to resolve this issue, we proposed a Cluster Based Multi-channel Assignment Scheme(CB-MAS) for adaptive tactical wireless mesh network. In the CB-MAS, the communication between the Cluster-Head(CH) and cluster number nodes uses a channel has no effect on channels being used by the inter-CH links. Therefore, the CB-MAS can minimize the interference within multi-channel environments. Our Simulation results showed that CB-MAS achieves improved the throughput and fairness index in WMN.

• 정보처리학회논문지C
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• 제13C권2호
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• pp.235-240
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• 2006

SCTP(Stream Control Transmission Protocol) 프로토콜의 '멀티홈잉(multi-homing)' 특성을 통해 SCTP 응용은 두 개 이상의 IP 주소를 통해 데이터를 전송할 수 있다. 본 논문에서는 리눅스 기반 테스트베드 환경에서 SCTP 멀티홈잉 특성이 처리율 성능에 미치는 영향을 분석한다. 실험을 위해 MSTNET 에뮬레이터를 활용하여 다양한 패킷손실율, 링크대역폭, 및 전송지연 환경을 구성하여 SCTP 처리율을 비교 분석 하였다. 실험 결과, 패킷 손실이 존재하는 망 환경에서 SCTP 멀티흠잉은 단일홈잉 경우에 비해 높은 성능을 보이며, 이는 SCTP 멀티홈잉에서 대체경로 재전송에 의한 효과로 볼 수 있다. 반면에, 링크대역폭 및 전송지연 요소는 상대적으로 SCTP 처리율 성능에 미치는 효과가 미미하였다.

• 대한전자공학회논문지TC
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• 제49권8호
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• pp.19-24
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• 2012

본 논문에서는 롱 홀 (long-haul) 다중 홉 무선 네트워크에서 단일 데이터 스트림에 대한 opportunistic 라우팅 기법의 성능분석을 수행한다. 성능분석에서는 네트워크 노드간의 링크 레벨 간섭을 고려한다. 일반적으로 opportunistic 라우팅 기법은 무선 다중 홉 네트워크의 성능을 크게 향상시킬 것으로 기대되어 왔고 이에 대한 성능향상 및 전송 기법에 대한 많은 연구가 수행되어 왔으나, 본 논문의 연구 결과는 롱 홀의 경우에는 opportunistic 라우팅의 성능향상 정도가 그리 크지 않다는 것을 보여준다. 이와 같은 연구 결과는 opportunistic 라우팅 기법은 구현의 복잡성을 고려할 경우에 롱 홀 환경에서는 적용하는 것이 적당치 않으며, 환경에 따라 short-haul 환경에 집중하여 적용해야 함을 의미한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.230-233
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• 2003

In this paper, it is shown that, in DS/CDMA mobile systems, halving or doubling the spreading factor (HSF or DSE) when retransmission is requested possibly improves the throughput. Given transmit power, DSF essentially decreases probability of packet error (PPE) by increasing the signal energy per information bit. It, however, doubles the time duration needed for transmitting the original packet. On the other hand, HSF increases PPE. It, however halves the time duration required to carry the original packet. Thus, the efficiency of HSF or DSF as a retransmission strategy depends on the amount of increased or reduced PPE after HSF or DSF is selected. With achieving given residual error probability (REP) in CDMA systems, the effective throughput is evaluated in this paper to find conditions with which HSF or DSF achieves better performance than using the original one. Analytic results show that HSF or DSF performs better when relatively small or big changes in their PPE's are present, respectively.

• 대한전자공학회논문지TC
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• 제47권3호
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• pp.31-38
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• 2010

본 논문에서는 MIMO-OFDM 시스템에 여러 MIMO 기법을 적용한 후 모의실험을 통하여 성능을 비교 및 분석하였고, 또한 Pre-coding, Antenna Subset Selection, AMC 기법을 적용하여 시스템을 분석하였다. 그리고 최종적으로 제안한 Adaptive-MCM(Adaptive-MIMO-Coding-Modulation) 기법의 성능을 분석하였다. 그 결과 4세대 이동통신 시스템에서 요구되고 있는 최대 전송률과 고품질 서비스의 Trade-off 관계를 개선할 수 있음을 확인하였다.

• 한국멀티미디어학회논문지
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• 제6권5호
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• pp.831-841
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• 2003

무선 ATM 망에서, 이동 단말기들은 유선 ATM 망의 단말기와 같은 기능과 QoS를 제공해 야 한다. 그러므로, 기지국 스케줄러에게 이동 단말기들의 ATM 셀 도착에 대한 정보가 빠르게 전달되는 것이 중앙 집중방식으로 제어되는 ATM 기반 MAC 프로토콜의 중요한 항목이다. 그러나, 다수 개의 무선 단말기들이 상향 링크를 통해 상호 경쟁적인 방법으로 데이터 전송을 요구하는 과정에서 충돌이 발생되고, 충돌에 의한 재전송 때문에 처리율이 감소되고 전송 지연이 증가하게 된다. 본 논문에서는 예약을 요청하는 단말기 수를 통계적으로 예측하고 사후 처리율을 고려하여 최적화된 request mini-slot의 개수를 결정하는 MAC 프로토콜을 제안한다. 시뮬레이션 결과에서 제안한 프로토콜이 지연과 처리율에서 높은 성능을 보임을 알 수 있었다.