• Title/Summary/Keyword: Network Range

Search Result 2,226, Processing Time 0.029 seconds

An Energy Efficient Topology Control Algorithm using Additional Transmission Range Considering the Node Status in a Mobile Wireless Sensor Network (이동성 있는 무선 센서 네트워크에서 노드의 상태를 고려한 에너지 효율적인 토폴로지 제어 방법)

  • Youn, Myungjune;Jeon, Hahn Earl;Kim, Seog-Gyu;Lee, Jaiyong
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.37B no.9
    • /
    • pp.767-777
    • /
    • 2012
  • Topology control increases channel efficiency by controlling transmission power of a node, and as a result, network lifetime and throughput are increased. However, reducing transmission range causes a network connectivity problem, especially in mobile networks. When a network loses connectivity, the network topology should be re-configured. However, topology re-configuration consumes lots of energy because every node need to collect neighbor information. As a result, network lifetime may decrease, even though topology control is being used to prolong the network lifetime. Therefore, network connectivity time needs to be increased to expend network lifetime in mobile networks. In this paper, we propose an Adaptive-Redundant Transmission Range (A-RTR) algorithm to address this need. A-RTR uses a redundant transmission range considering a node status and flexibly changes a node's transmission range after a topology control is performed.

Neural Network Based Camera Calibration and 2-D Range Finding (신경회로망을 이용한 카메라 교정과 2차원 거리 측정에 관한 연구)

  • 정우태;고국원;조형석
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1994.10a
    • /
    • pp.510-514
    • /
    • 1994
  • This paper deals with an application of neural network to camera calibration with wide angle lens and 2-D range finding. Wide angle lens has an advantage of having wide view angles for mobile environment recognition ans robot eye in hand system. But, it has severe radial distortion. Multilayer neural network is used for the calibration of the camera considering lens distortion, and is trained it by error back-propagation method. MLP can map between camera image plane and plane the made by structured light. In experiments, Calibration of camers was executed with calibration chart which was printed by using laser printer with 300 d.p.i. resolution. High distortion lens, COSMICAR 4.2mm, was used to see whether the neural network could effectively calibrate camera distortion. 2-D range of several objects well be measured with laser range finding system composed of camera, frame grabber and laser structured light. The performance of 3-D range finding system was evaluated through experiments and analysis of the results.

  • PDF

Grouping Algorithms of Zigbee Nodes for Efficient Data Transmission to Long Range (효율적인 원거리 데이터 전송을 위한 Zigbee 노드들의 그룹화 알고리즘)

  • Woo, Sung-Je;Shin, Bok-Deok
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.61 no.4
    • /
    • pp.632-638
    • /
    • 2012
  • ZigBee network, based on PHY, MAC layer provides a specification for a suite of high level communication protocols using small, low-power digital radio based on an IEEE 802.15.4 standard. Meshing is a type of daisy chaining from one device to another. This technique allows the short range of an individual node to be expanded and multiplied, covering a much larger area. Each wireless technology that makes it to market serves a special purpose or function. Zigbee provides short-range connectivity in what is called a personal-area network (PAN). Within ZigBee PAN coordinator as manages an entire ZigBee network, the short range of frequency band was only selected because the technology allows typically less than 100 kbp or ZigBee troubles in retransmission processing and delaying data tranmission works to create unproductive condition of work. This research was proposed the method, based on short range frequency of zigBee nodes enable to long range of remote data transmission with specific algorithm tools.

Control Network using Bluetooth with Wire Network (유선 네트워크 기반의 근거리 무선 통신을 이용한 제어용 네트워크)

  • Gwak, Jae-Hyeok;Im, Jun-Hong
    • Proceedings of the KIEE Conference
    • /
    • 2003.11c
    • /
    • pp.476-479
    • /
    • 2003
  • Recently, Bluetooth has been regarded as a new technology for short-range wireless connection. Although initial application of Bluetooth technology has been focused mainly on replacing cables between hand-held devices due to a limited packet size and short-range, general wireless telecommunication such as PAN and Ad hoc networks via Bluetooth-equipped devices is expected to be one of the most popular applications. Wireless equipments have been used to exchange data between host and mobile unit. The exchanging data may be several bytes of control command and the value of sensors with ultra-sonic, vision sensor, and encoder from mobile robot. However, most wireless equipments have some drawbacks such as lack of authentication, large size and high price. On the other hand, the benefits of Bluetooth are small size, low power, low price except short-range. Especially, there are some difficulties when wireless modules are used in indoor environments. In this paper, a method of using wire network in Bluetooth network is investigated as a solution to overcome the short-range problem of Bluetooth and difficulty in indoor environment.

  • PDF

Long-Range Dependence and 1/f Noise in a Wide Area Network Traffic (광역 네트워크 트래픽의 장거리 상관관계와 1/f 노이즈)

  • Lee, Chang-Yong
    • Journal of KIISE:Information Networking
    • /
    • v.37 no.1
    • /
    • pp.27-34
    • /
    • 2010
  • In this paper, we examine a long-range dependence in an active measurement of a network traffic which has been a well known characteristic from analyses of a passive network traffic measurement. To this end, we utilize RTT(Round Trip Time), which is a typical active measurement measured by PingER project, and perform a relevant analysis to a time series of both RTT and its volatilities. The RTT time series exhibits a long-range dependence or a 1/f noise. The volatilities, defined as a higher-order variation, follow a log-normal distribution. Furthermore, volatilities show a long-range dependence in relatively short time intervals, and a long-range dependence and/or 1/f noise in long time intervals. From this study, we find that the long-range dependence is a characteristic of not only a passive traffic measurement but also an active measurement of network traffic such as RTT. From these findings, we can infer that the long-range dependence is a characteristic of network traffic independent of a type of measurements. In particular, an active measurement exhibits a 1/f noise which cannot be usually found in a passive measurement.

Social Network Effects on Travel Agency Employees' Occupational Outcomes: Innovation Behavior as a Mediator

  • Lee, Byeong-Cheol
    • Journal of Distribution Science
    • /
    • v.15 no.6
    • /
    • pp.13-24
    • /
    • 2017
  • Purpose - The current study aims to examine the effect of social network factors on travel agency employees' occupational outcomes such as job performance and job satisfaction through innovation behavior in a comprehensive model. Research design, data, and methodology - Based on a theory of social network, the concept of social network was assessed by three factors: a) network size, b) network range, and c) tie strength. To test the proposed hypotheses, structural equation modeling (SEM) was employed based on data from 197 travel agency employees in Korea. Result - The results showed that the associational activity of network size had a positive effect on innovation behavior, while the network range of network size had a significant negative effect on innovation behavior. Subsequently, innovation behavior positively influenced on job performance and job satisfaction, respectively. Conclusions - The results offer some insights into the extended model and have important managerial implications for Korean travel agencies. More specifically, considering diverse domains of social network and organizational research, this study advances critical utility of social network factors in a high facilitating level of innovation behavior, which can help travel agency employees promote their job performance and job satisfaction.

An Improved Vehicle Tracking Scheme Combining Range-based and Range-free Localization in Intersection Environment (교차로 환경에서 Range-based와 Range-free 위치측정기법을 혼합한 개선된 차량위치추적기법)

  • Park, Jae-Bok;Koh, Kwang-Shin;Cho, Gi-Hwan
    • Journal of the Institute of Electronics Engineers of Korea CI
    • /
    • v.48 no.2
    • /
    • pp.106-116
    • /
    • 2011
  • USN(Ubiquitous Sensor Network) environment permits us to access whatever information we want, whenever we want. The technologies to provide a basement to these environments premise an accurate location establishment. Especially, ITS(Intelligent Transportation Systems) is easily constructed by applying USN technology. Localization can be categorized as either Range-based or Range-free. Range-based is known to be not suitable for the localization based on sensor network, because of the irregularity of radio propagation and the additional device requirement. The other side, Range-free is much appropriated for the resource constrained sensor network because it can actively locate by means of the communication radio. But, generally the location accuracy of Range-free is low. Especially, it is very low in a low-density environment. So, these two methods have both merits and demerits. Therefore, it requires a new method to be able to improve tracking accuracy by combining the two methods. This paper proposes the tracking scheme based on range-hybrid, which can markedly enhance tracking accuracy by effectively using the information of surrounding nodes and the RSSI(Received Signal Strength Indication) that does not require additional hardware. Additionally, we present a method, which can improve the accuracy of vehicle tracking by adopting the prediction mechanism. Simulation results show that our method outperforms other methods in the transportation simulation environment.

A Position Sensorless Control System of SRM over Wide Speed Range

  • Baik, Won-Sik
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.22 no.3
    • /
    • pp.66-73
    • /
    • 2008
  • This paper presents a position sensorless control system of SRM over wide speed range. Due to the doubly salient structure of the SRM, the phase inductance varies along with the rotor position. Most of the sensorless control techniques are based on the fact that the magnetic status of the SRM is a function of the angular rotor position. The rotor position estimation of the SRM is somewhat difficult because of its highly nonlinear magnetizing characteristics. In order to estimate more accurate rotor position over wide speed range, Neural Network is used for this highly nonlinear function approximation. Magnetizing data patterns of the prototype 1-hp SRM are obtained from locked rotor test, and used for the Neural Network training data set. Through measurement of the flux-linkage and phase currents, rotor position is able to estimate from current-flux-rotor position lookup table which is constructed from trained Neural Network. Experimental results for a 1-hp SRM over 16:1 speed range are presented for the verification of the proposed sensorless control algorithm.

Using Range Extension Cooperative Transmission in Energy Harvesting Wireless Sensor Networks

  • Jung, Jin-Woo;Ingram, Mary Ann
    • Journal of Communications and Networks
    • /
    • v.14 no.2
    • /
    • pp.169-178
    • /
    • 2012
  • In this paper, we study the advantages of using range extension cooperative transmission (CT) in multi-hop energy harvesting wireless sensor networks (EH-WSNs) from the network layer perspective. EH-WSNs rely on harvested energy, and therefore, if a required service is energy-intensive, the network may not be able to support the service successfully. We show that CT networks that utilize both range extension CT and non-CT routing can successfully support services that cannot be supported by non-CT networks. For a two-hop toy network, we show that range extension CT can provide better services than non-CT. Then, we provide a method of determining the supportable services that can be achieved by using optimal non-CT and CT routing protocols for EH-WSNs. Using our method and network simulations, we justify our claim that CT networks can provide better services than nonCT networks in EH-WSNs.

Runway visual range prediction using Convolutional Neural Network with Weather information

  • Ku, SungKwan;Kim, Seungsu;Hong, Seokmin
    • International Journal of Advanced Culture Technology
    • /
    • v.6 no.4
    • /
    • pp.190-194
    • /
    • 2018
  • The runway visual range is one of the important factors that decide the possibility of taking offs and landings of the airplane at local airports. The runway visual range is affected by weather conditions like fog, wind, etc. The pilots and aviation related workers check a local weather forecast such as runway visual range for safe flight. However there are several local airfields at which no other forecasting functions are provided due to realistic problems like the deterioration, breakdown, expensive purchasing cost of the measurement equipment. To this end, this study proposes a prediction model of runway visual range for a local airport by applying convolutional neural network that has been most commonly used for image/video recognition, image classification, natural language processing and so on to the prediction of runway visual range. For constituting the prediction model, we use the previous time series data of wind speed, humidity, temperature and runway visibility. This paper shows the usefulness of the proposed prediction model of runway visual range by comparing with the measured data.