• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • 2
  • Tagged with
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

以公車亭為基礎之耐延遲車載網路封包轉發策略 / A kiosk based packet forwarding strategy in vehicular delay tolerant networks

陳維偵, Chen, Wei Chen Unknown Date (has links)
在耐延遲網路(Delay Tolerant Network)中,因節點之間的高移動性、連接的不確定性環境嚴苛限制,採用Store-And-Forward 訊息傳輸的模式提供一個可接受的網路表現。常見的路由協定可分為機會路由、基於預測的路由以及調度路由,然而這些路由協定使用在市區環境中,有些許不足的地方,因此我們提出適用在市區封包轉發策略。 我們提出的以公車亭為基礎之耐延遲車載網路封包轉發策略,是在市區環境中建立一個以公車亭為基礎的資料傳送架構,包含汽車、公車、公車站、公車轉運站四種節點。我們建立節點與節點相遇時資料傳送規則,例如汽車與汽車相遇、汽車與公車相遇、公車與公車站相遇、公車與公車轉運站相遇、公車轉運站與公車相遇、公車站與汽車相遇、汽車與目的地相遇時各自有不同的資料傳送判斷與限制。 實驗結果也證明所提出的演算法,除了可以有效地減少延遲傳送時間並提高訊息成功傳送率,及在各節點有限的緩衝區大小下,我們的封包轉發策略有著最突出的效能。 / In Delay Tolerant Networks (DTNs), there does not exist an end-to-end path due to intermittent connectivity and high node mobility. Messages are stored for a period of time at network nodes and are conveyed hop-by-hop to the destination. The current DTN routing protocols can be summarized into three categories: opportunistic, prediction-based and scheduling protocols. However, these routing protocols have some deficiencies and are not specifically focused on the urban areas. Based on the characteristics of urban areas, we proposed a kiosk based packet forwarding strategy for vehicular delay tolerant networks. We established the rules of data transmission when one node contacts other nodes. More specifically, Car-to-Car, Car-to-Bus, Bus-to-Bus stop, Bus-to-Bus transfer station, Bus transfer station-to-Bus, Bus stop-to-Car ,Car-to-Destination contacts, have different judgments and restrictions for data forwarding. The simulation results demonstrate that we proposed packet forwarding strategy would reduce the delivery delay, and improve the successful delivery rate. Especially with limited buffer and little overhead, our proposed strategy has the most prominent performance.
2

以耐延遲車載網路方式,收集路況資訊與彙整時程評估 / Gathering Road Traffic Information and Consolidating Travel Time Estimation using Vehicular Delay Tolerant Networks

王林瀚, Wang, Lin Han Unknown Date (has links)
許多國家正面臨因嚴重的交通壅塞所帶來龐大的經濟損失,同樣在台灣也面臨相同問題,根本解決之道就是找出壅塞路段,並即時地告知車輛駕駛以迴避此路段。因此如何有效率地偵測出壅塞路段,是當前重要的議題。以往大多透過長期所累積的統計數據,針對各路段收集行駛於該路段所有車輛的平均速度,來獲得該路段的交通狀況,但卻無法立即反應即時路況。 因此我們提出以耐延遲車載網路方式,收集路況資訊與彙整旅途時程,透過具有全球定位系統(GPS)以及無線網路的車輛來進行路況交通資訊的收整與交換。再透過本研究所提出路況交通覺知路由協定(RTARP),以One-Hop Controlled Flooding的傳輸方式在節點與節點相遇時進行路況資訊的傳送,進而交換節點彼此間各自所存放各路段的路況資訊。 模擬實驗結果證明我們所提出的路由協定在路況交通資訊交換中,有效地減少網路傳輸負載、提高訊息送達成功率以及路況交通資訊(RTI)正確率。 / Many countries are concerning about the huge economic losses caused by the critical traffic congestion. We have the same problem in Taiwan. The solutions lie in finding the road section with traffic congestion first and informing drivers to avoid that section. But how to detect the road section with traffic congestion effectively is the most important issue of this research. Conventionally, the real-time road traffic is mostly predicted by long-term accumulated statistics calculated by the collection of the average speed of cars on the same road section. But this way can’t provide the real-time road traffic immediately. Based on vehicles with GPS and the capability of WiFi, we proposed gathering road traffic information and consolidating travel time estimation using vehicular delay tolerant networks. We also proposed the Road Traffic Awareness Routing Protocol (RTARP) to exchange the road traffic information preserved individually by One-Hop Controlled Flooding during nodes’ encounter. The results of simulations prove the routing protocol we proposed can effectively reduce the transmission overhead, improve the delivery ratio and the accuracy of the road traffic information.

Page generated in 0.0627 seconds