• 인터넷정보학회논문지
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• 제11권1호
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• pp.1-13
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• 2010

네트워크 장비를 관리함에 있어서 환경에 따른 RED(Random Early Detection) 매개변수에 대한 설정은 쉽지 않은 일이다. 특히 관리자가 환경의 변화에 따라 일정한 서비스율을 유지하고 싶은 경우의 매개변수 설정은 더욱 쉽지 않은 일이다. 본 논문에서는 출력 큐에 멀티 코어 CPU를 탑재한 라우터를 가정하고 라우터의 출력 큐에, RED의 환경에 따른 매개변수의 최적화에 적합한 것으로 알려진, 인공지능의 유전 알고리즘을 직접적으로 도입하여 스스로 부하에 적응하는 AI RED(Artificial Intelligence RED)를 제안한다. AI RED는 FuRED(Fuzzy-Logic-based RED) 보다 단순하고 세밀하며, 실험을 통하여 AI RED가 찾아낸 RED 매개변수는 표준 RED 매개변수보다 환경에 더욱 잘 적응하는 효율적인 서비스를 제공하여 준다는 것을 확인 할 수 있다. RED 매개변수 관리의 자동화는 네트워크 관리의 측면에서 많은 효율성의 향상을 관리자에게 제공하여 줄 수 있다.

• 대한전자공학회논문지TC
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• 제40권12호
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• pp.83-93
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• 2003

IP 망에서의 차별 서비스 구조는 품질 보장 서비스를 위해 대역폭 브로커를 기반으로 QoS프로비저닝의 제어 및 관리를 수행한다. 그러나, 이러한 대역폭 브로커는 모든 입구 에지 노드로 유입되는 호의 연결 수락 제어를 위해 중앙 집중형 자원 관리를 수행함에 따라 확장성 면에서 큰 단점을 갖는다. 본 논문에서는 대역폭 브로커를 갖는 차별 서비스 구조에서 확장성을 높이고 유입되는 호의 상태를 반영한 적응적 연결 수락 제어 메커니즘을 제안하고자 한다. 이를 위해 대역폭 브로커의 기능을 입구 에지 노드와 분리해서 자원 관리 및 프로비저닝을 대역폭 브로커에서 수행하고, 입구 에지 노드에서는 연결 수락 제어를 담당한다. 입구 에지 노드에서는 연결 수락제어를 위해 각 에지 노드간 패스 개념을 도입하고, 패스 단위로 할당된 대역 기반으로 연결 수락 제어를 수행한다. 패스 별 할당 대역량은 유입되는 트래픽에 따라 적응적으로 변화하게 되며 이는 대역록 브로커와의 통신을 최소화하면서 대역 자원의 효율적인 사용을 가능케 한다. 본 논문에서는 이러한 적응적 연결 수락 메커니즘을 제안하고 성능 분석을 통한 효율성 및 확장성의 개선을 제시하고자 한다.

• 한국멀티미디어학회논문지
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• 제19권11호
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• pp.1871-1877
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• 2016

In this paper, a Wireless USB (WUSB) protocol is adopted for development of ASMD (Adaptive Source Multi Device) N-screen wireless services. WUSB is the USB technology merged with WiMedia PHY and Distributed-MAC (D-MAC). However, the current WUSB protocol can't provide seamless N-screen streaming services to moving WUSB devices in home network environment. Therefore, to provide the ASMD N-screen services through WUSB based on D-MAC protocol, a channel management scheme is proposed to support seamless mobility between adjacent ASMD groups for wireless IPTV N-screen services. In simulation results, proposed ASMD channel management (ACM) scheme is compared with conventional WUSB channel management scheme in view points of throughput, average path interference and energy consumption according to various numbers of nodes and elapsed simulation times. Through simulation results, it is explained that proposed ASMD channel management (ACM) scheme should be adopted in the WUSB protocol to realize ASMD N-screen wireless services.

• International Journal of Computer Science & Network Security
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• 제22권10호
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• pp.191-200
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• 2022

Constrained Application Protocol (CoAP) is a standardized protocol by the Internet Engineering Task Force (IETF) for the Internet of things (IoT). IoT devices have limited computation power, memory, and connectivity capabilities. One of the significant problems in IoT networks is congestion control. The CoAP standard has an exponential backoff congestion control mechanism, which may not be adequate for all IoT applications. Each IoT application would have different characteristics, requiring a novel algorithm to handle congestion in the IoT network. Unnecessary retransmissions, and packet collisions, caused due to lossy links and higher packet error rates, lead to congestion in the IoT network. This paper presents an adaptive congestion control protocol for CoAP, Adaptive Congestion Control with a Backoff algorithm (ACCB). AACB is an extension to our earlier protocol AdCoCoA. The proposed algorithm estimates RTT, RTTVAR, and RTO using dynamic factors instead of fixed values. Also, the backoff mechanism has dynamic factors to estimate the RTO value on retransmissions. This dynamic adaptation helps to improve CoAP performance and reduce retransmissions. The results show ACCB has significantly higher goodput (49.5%, 436.5%, 312.7%), packet delivery ratio (10.1%, 56%, 23.3%), and transmission rate (37.7%, 265%, 175.3%); compare to CoAP, CoCoA+ and AdCoCoA respectively in linear scenario. The results show ACCB has significantly higher goodput (60.5%, 482%,202.1%), packet delivery ratio (7.6%, 60.6%, 26%), and transmission rate (40.9%, 284%, 146.45%); compare to CoAP, CoCoA+ and AdCoCoA respectively in random walk scenario. ACCB has similar retransmission index compare to CoAp, CoCoA+ and AdCoCoA respectively in both the scenarios.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.110-113
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• 1999

In this paper. we propose an adaptive handover scheme in wireless network The proposed handover scheme is a hybrid type of virtual path extension and rerouting. The proposed handover scheme chooses the virtual path management scheme according to the service QoS instead of the network topology which is used in the previous hybrid handover schemes. The proposed scheme supports the seamless service and small buffering during virtual path rerouting handover through the multicasting service. To evaluate the performance of the proposed scheme. we compute the number of signaling message used for handover and perform computer simulation. The simulation results show that the proposed scheme provides more efficiency in the handover delay and seamless service than the previous methods.

• 스마트미디어저널
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• 제13권1호
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• pp.45-51
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• 2024

Long Range Wide Area Network (LoRaWAN) is a widely adopted Internet of Things (IoT) protocol due to its high range and lower energy consumption. LoRaWAN utilizes Adaptive Data Rate (ADR) for efficient resource (e.g., spreading factor and transmission power) management. The ADR manages these two resource parameters on the network server side and end device side. This paper focuses on analyzing the ADR and Gaussian ADR performance of LoRaWAN. We have performed NS3 simulation under a static scenario by varying the antenna height. The simulation results showed that antenna height has a significant impact on the packet delivery ratio. Higher antenna height (e.g., 50 m) has shown an improved packet success ratio when compared with lower antenna height (e.g., 10 m) in static and mobility scenarios. Based on the results, it is suggested to use the antenna at higher allevation for successful packet delivery.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권5호
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• pp.2469-2490
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• 2019

A low-energy adaptive clustering hierarchy (LEACH) protocol is a low-power adaptive cluster routing protocol which was proposed by MIT's Chandrakasan for sensor networks. In the LEACH protocol, the selection mode of cluster-head nodes is a random selection of cycles, which may result in uneven distribution of nodal energy and reduce the lifetime of the entire network. Hence, we propose a new selection method to enhance the lifetime of network, in this selection function, the energy consumed between nodes in the clusters and the power consumed by the transfer between the cluster head and the base station are considered at the same time. Meanwhile, the improved FTBA algorithm integrating the curve strategy is proposed to enhance local and global search capabilities. Then we combine the improved BA with LEACH, and use the intelligent algorithm to select the cluster head. Experiment results show that the improved BA has stronger optimization ability than other optimization algorithms, which the method we proposed (FTBA-TC-LEACH) is superior than the LEACH and LEACH with standard BA (SBA-LEACH). The FTBA-TC-LEACH can obviously reduce network energy consumption and enhance the lifetime of wireless sensor networks (WSNs).

• 정보처리학회논문지C
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• 제13C권2호
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• pp.171-176
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• 2006

최근 무선통신 기술의 비약적인 발전과 함께, 이동 셀룰러 네트워크 상에서 다양한 형태의 멀티미디어 서비스에 대한 수요가 폭발적으로 증가하고 있다. 그러나, 무선 네트워크의 특성상 유선 네트워크에 비해 상대적으로 제한된 대역폭을 가지기 때문에 효율적인 대역폭 관리가 중요한 이슈이다. 본 논문에서는 이동 셀룰러 네트워크상에서의 멀티미디어 서비스를 효율적으로 지원할 수 있는 적응적 온라인 대역폭 관리 알고리즘을 제안하였다. 이 기법은 현재 네트워크의 트래픽 상황을 기반으로 하여 실시간으로 시스템을 관리하여 우선순위가 높은 서비스의 QoS 보장과 동시에 효율적인 대역폭 사용률을 제공한다. 컴퓨터 시뮬레이션을 통하여 대역폭 관리를 위해 제안된 기존의 타 기법들과의 비교, 분석을 수행하여 제안된 방법이 다앙한 네트워크 트래픽 상황에서 우수한 성능을 가지는 것을 확인할 수 있었다.

• International journal of advanced smart convergence
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• 제12권4호
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• pp.147-153
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• 2023

In recent times, an absence of effective crowd management has led to numerous stampede incidents in crowded places. A crucial component for enhancing on-site crowd management effectiveness is the utilization of crowd counting technology. Current approaches to analyzing congested scenes have evolved beyond simple crowd counting, which outputs the number of people in the targeted image to a density map. This development aligns with the demands of real-life applications, as the same number of people can exhibit vastly different crowd distributions. Therefore, solely counting the number of crowds is no longer sufficient. CSRNet stands out as one representative method within this advanced category of approaches. In this paper, we propose a crowd counting network which is adaptive to the change in the density of people in the scene, addressing the performance degradation issue observed in the existing CSRNet(Congested Scene Recognition Network) when there are changes in density. To overcome the weakness of the CSRNet, we introduce a system that takes input from the image's information and adjusts the output of CSRNet based on the features extracted from the image. This aims to improve the algorithm's adaptability to changes in density, supplementing the shortcomings identified in the original CSRNet.

• Journal of Electrical Engineering and Technology
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• 제3권2호
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• pp.285-291
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• 2008

Active Queue Management(AQM) has been widely used for congestion avoidance in Transmission Control Protocol(TCP) networks. Although numerous AQM schemes have been proposed to regulate a queue size close to a reference level, most of them are incapable of adequately adapting to TCP network dynamics due to TCP's non-linearity and time-varying stochastic properties. To alleviate these problems, we introduce an AQM technique based on a dynamic neural network using the Back-Propagation(BP) algorithm. The dynamic neural network is designed to perform as a robust adaptive feedback controller for TCP dynamics after an adequate training period. We evaluate the performances of the proposed neural network AQM approach using simulation experiments. The proposed approach yields superior performance with faster transient time, larger throughput, and higher link utilization compared to two existing schemes: Random Early Detection(RED) and Proportional-Integral(PI)-based AQM. The neural AQM outperformed PI control and RED, especially in transient state and TCP dynamics variation.