• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권7호
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• pp.3433-3446
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• 2019

Aiming at the high complexity of traditional single-channel demodulation algorithm for PCMA signals, a new demodulation algorithm based on neural network is proposed to reduce the complexity of demodulation in the system of non-cooperative PCMA communication. The demodulation network is trained in this paper, which combines the preprocessing module and decision module. Firstly, the preprocessing module is used to estimate the initial parameters, and the auxiliary signals are obtained by using the information of frequency offset estimation. Then, the time-frequency characteristic data of auxiliary signals are obtained, which is taken as the input data of the neural network to be trained. Finally, the decision module is used to output the demodulated bit sequence. Compared with traditional single-channel demodulation algorithms, the proposed algorithm does not need to go through all the possible values of transmit symbol pairs, which greatly reduces the complexity of demodulation. The simulation results show that the trained neural network can greatly extract the time-frequency characteristics of PCMA signals. The performance of the proposed algorithm is similar to that of PSP algorithm, but the complexity of demodulation can be greatly reduced through the proposed algorithm.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권6호
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• pp.2964-2985
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• 2019

Global data center IP traffic is expected to reach 20.6 zettabytes (ZB) by the end of 2021. Intra-data center networks (Intra-DCN) will account for 71.5% of the data center traffic flow and will be the largest portion of the traffic. The understanding of traffic distribution in IntraDCN is still sketchy. It causes significant amount of bandwidth to go unutilized, and creates avoidable choke points. Conventional transport protocols such as Optical Packet Switching (OPS) and Optical Burst Switching (OBS) allow a one-sided view of the traffic flow in the network. This therefore causes disjointed and uncoordinated decision-making at each node. For effective resource planning, there is the need to consider joining the distributed with centralized management which anticipates the system's needs and regulates the entire network. Methods derived from Kalman filters have proved effective in planning road networks. Considering the network available bandwidth as data transport highways, we propose an intelligent enhanced SDN concept applied to OBS architecture. A management plane (MP) is added to conventional control (CP) and data planes (DP). The MP assembles the traffic spatio-temporal parameters from ingress nodes, uses Kalman filtering prediction-based algorithm to estimate traffic demand. Prior to packets arrival at edges nodes, it regularly forwards updates of resources allocation to CPs. Simulations were done on a hybrid scheme (1+1) and on the centralized OBS. The results demonstrated that the proposition decreases the packet loss ratio. It also improves network latency and throughput-up to 84 and 51%, respectively, versus the traditional scheme.

• 한국정보통신학회논문지
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• 제21권9호
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• pp.1655-1665
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• 2017

최근 많은 클라우드 서비스 제공자, 기업, 연구소 등에서 데이터센터를 활발히 구축하고 있다. 일반적으로 데이터 센터는 부하 분산을 위해 ECMP 데이터 포워딩 기법을 사용하여 트리 토폴로지 형태로 구축된다. 본 논문에서는 트리 토폴로지와 팻트리 토폴로지를 살펴보고, 또한 MLAG와 ECMP 같은 부하 분산 기술을 알아본다. 그리고 데이터 센터내의 호스트에 저장되어 있는 특정 파일을 데이터센터 외부로 효율적으로 송신할 수 있는 스케줄링 알고리즘을 제안한다. 제안된 알고리즘은 팻트리 토폴로지와 오픈플로우 프로토콜을 이용한다. 수치해석을 통해 성능 분석을 수행하며, ECMP의 성능과 비교한다. 이러한 성능 비교를 통해 평균처리율과 파일전송완료시간에 있어서 제안된 알고리즘의 성능이 우수함을 보인다.

• Genomics & Informatics
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• 제14권1호
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• pp.2-11
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• 2016

The advances in mass spectrometry-based proteomics technologies have enabled the generation of global proteome data from tissue or body fluid samples collected from a broad spectrum of human diseases. Comparative proteomic analysis of global proteome data identifies and prioritizes the proteins showing altered abundances, called differentially expressed proteins (DEPs), in disease samples, compared to control samples. Protein biomarker candidates that can serve as indicators of disease states are then selected as key molecules among these proteins. Recently, it has been addressed that cellular pathways can provide better indications of disease states than individual molecules and also network analysis of the DEPs enables effective identification of cellular pathways altered in disease conditions and key molecules representing the altered cellular pathways. Accordingly, a number of network-based approaches to identify disease-related pathways and representative molecules of such pathways have been developed. In this review, we summarize analytical platforms for network-based protein biomarker discovery and key components in the platforms.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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• pp.251-254
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• 2006

A precise real-time method of using the IGS ultra rapid products (IGU) and the GPS broadcast ephemeris to calculate the VRS orbit corrections was presented here which was suited for GPS/VRS reference station network based positioning. Test data acquired from both the SGRSN (Sichuan GPS Reference Station Network) and SCIGN (Southern California integrated GPS network) were used to evaluate the performance of the modeling techniques. The new method was proven to be more precise and reliable compared with the existing conventional network-based orbit error interpolation method. It was shown that 0.004ppm relative accuracy was reached, namely the influence from the orbit bias for the RTK positioning within 100km area can be of sub-millimeter level.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제9권2호
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• pp.31-36
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• 2020

국방 통합 데이터센터(DIDC : Defense Integrated Data Center)의 설립으로 인력, 운영 비용 감소 및 효율적인 자원 관리가 가능해졌다. 그러나 4차 산업혁명과 더불어 미래의 전장에 추가될 드론, 로봇, IoT 등의 장비에서 나오는 수많은 전장의 데이터를 효과적으로 수집하고 관리하는 것이 현 체계를 통해서는 어려움이 있는 것이 사실이다. 따라서 이러한 점을 극복하기 위해 이동 통신 기술인 5G의 핵심 기술로 부상하고있는 네트워크 기술인 NFV와 SDN을 이용한 DIDC의 네트워크 체계에 대한 설계를 제안하고자 한다. 장비의 데이터 시트를 분석을 통해 장비마다 동일하게 존재하는 중복 기능을 하나의 VNF로 통합하여 트래픽을 처리한다면 에너지 효율성 증대 및 더욱더 효과적인 네트워크 관리가 가능할 것으로 판단한다.

• 한국통신학회:학술대회논문집
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• 한국통신학회 2006년도 하계종합학술발표회 논문 초록집
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• pp.277-277
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• 2006

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.211-214
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• 2005

There are emerging many eScience applications. More and more scientists want to collaborate on their investigation with international partners without space limitation by using these applications. Since these applications have to analyze the massive raw data, scientists need to send and receive the data in short time. So today's network related requirement is high speed networking. The key point of network performance is transport protocol. We can use TCP and UDP as transport protocol but we use TCP due to the data reliability. However, TCP was designed under low bandwidth network, therefore, general TCP, for example Reno, cannot utilize the whole bandwidth of high capacity network. There are several TCP variants to solve TCP problems related to high speed networking. They can be classified into two groups: loss based TCP and delay based TCP. In this paper, I will compare two approaches of TCP variants and propose a hybrid approach for high speed networking.

• 대기
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• 제20권2호
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• pp.153-160
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• 2010

In this paper, an attempt has been made to build and test self-configuring weather sensor networks and internet based observation system to gather atmospheric data. The aim is to provide integrated or real-time weather information in standard form using network data access protocol. This system was successfully developed to record weather information both digital as well as visual using sensor network and web-enabled surveillance cameras. These data were transformed by network based data access protocol to access and utilize for public domain. The competed system has been successfully utilized to monitor different types of weather. The results show that this is one of the most useful weather monitoring system.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2004년도 하계학술대회
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• pp.328-333
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• 2004

SK Telecom은 2000년 10월 세계 최초로 기존 IS-95A/B망에서 지원하였던 속도인 14.4Kbps나 56Kbps 보다 훨씬 빠른 최고 144Kbps로 무선인터넷이 가능한 CDMA2000 IX를 상용화 하였다. 또한, 2002년 1월에는 CDMA2000 IX보다 15배 이상 빠른 최대 2.4Mbps가 가능한 동기식 3세대 망인 CDMA2000 IxEV-DO를 세계 최초로 상용화 하였다. 이러한 초고속 무선 인터넷 서비스를 위해서 패킷 데이터 처리에 필수적인 PDSN(Packet Data Serving Node), HA(Home Agent), AAA(Authentication, Authorization and Accounting) 등의 노드들로 구성된 Packet Core Network(이하 PCN)이 도입되었으며, 이에 대한 운용 및 관리 방안이 중요한 issue로 등장하였다. 본 논문에서는 기존의 음성 서비스 관리를 위한 망관리 시스템(Network Management System)과는 다른 개념으로 관리되어야 할 패킷 서비스를 위한 NMS 구축 방안을 제시하고, 필수적인 관리 정보 및 서비스 관리를 위한 방향을 제시한다.