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  • 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

Wavelet Based Video Compression for A Low-Rate Data Link

Landry, Michael W., Lee, Jeffrey C. 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Conventional video image transmission requires large data bandwidths, whether the signals are transmitted in analog or digital form. Many applications are limited to bandwidths that will not support image transmission unless high compression ratios are employed. Video compression techniques based on wavelet functions provide high data compression while preserving image quality, but are computationally demanding. Recently available high-integration devices that utilize wavelet basis functions for video compression have made possible low-cost high-performance video compression systems. Image data is more useful when provided with other data such as position information, telemetry, or other user data. This paper describes the technology, features, and limitations of a versatile low data rate system incorporating compressed video data.
2

AIRBORNE/SHIPBORNE PSK TELEMETRY DATA LINK

CARLSON, JOHN R., SCHMIDT, ARLEN 11 1900 (has links)
International Telemetering Conference Proceedings / November 04-07, 1991 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper describes the design considerations and methodology applied to solve the practical problems posed in the creation of a high bit rate telemetry relay system and specifically the techniques implemented to enhance signal to noise performance under adverse operational conditions.
3

DEVELOPMENT OF THE VHF AIR/GROUNG DATA LINK FOR CAAC

Qing, Zhong, Qi-shan, Zhang, Xingjian, Huang 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / The VHF air/ground data link of CAAC is introduced in detail. This paper proposes a solution of VHF air/ground data link system, which exchanges downlink messages and uplink messages in data link information processing networks. The following topics are covered in this paper: components of VHF data link; data processing and design about VHF data link Gateway system; the application of VHF air/ground data link in airlines.
4

A reliable data channel for underwater communications using phase shift keying

Davidson, H. D. January 1988 (has links)
No description available.
5

A Vehicle Tracking System Based on GPS

Yongqian, Wang, Xianliang, Li, Qishan, Zhang 11 1900 (has links)
International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / Vehicle tracking system based on GPS has been paid more and more attention. The system consists of GIS (Geological Information System), master station, movable station and communication network. Movable stations installed on automobiles transmit their position and status messages to the master station. All vehicles' tracks are drawn on the electrical map displayed by the master station's computer screen in real time. Vehicles' alarming signals can also be transmitted to the master station simultaneously. This paper presents a whole designing scheme of the vehicle tracking system, then it makes a thorough introduction to the system's performance and working procedure. The key technologies employed by the system and the relations between them are also discussed in details in the paper.
6

Robust connection-less service over a packet satellite link

Samaraweera, Nihal Kithsiri Gamage January 1995 (has links)
The intention of the study presented in this thesis is to obtain an understanding of the issues involved in using connection-less services over a non-reliable satellite link and to suggest suitable solutions to enhance packet communication services. Particular attention is paid to using VSAT systems for interconnecting LANs through satellite links. A detailed study of Connection-Less Services (CLNS) and end to end transport protocols that use the CLNS over a satellite link with different propagation conditions is presented. Since most existing link, network and transport protocols were originally designed to work with terrestrial networks, they do not necessarily perform well over a satellite link. The main weaknesses in the link protocols are the insufficiency of connection-less data link services, the interaction between error recovery procedures implemented by transport layer and link layer and the interaction between different conversations due to link layer error recovery procedures. The inefficiency in the segmentation and reassembling service is the main weakness in the network protocol. The weaknesses in the transport protocols are the interaction between error recovery procedures and congestion control procedures, the significant delay in receiving feed-back from the remote receiver, the oscillating behaviour of the congestion control algorithms and the inaccuracy of round trip time estimation. Two approaches were used to improve the connection-less service over a satellite link. First, new data link protocols were developed to transparently improve the network service. The second approach was to modify transport protocols (which provide end to end transport service) to suit the characteristics of the satellite network.
7

iPCM Telemetry System

Leite, Nelson Paiva Oliveira, Carvalho, Marco Aurélio 10 1900 (has links)
ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / The execution of experimental Flight Test Campaign (FTC) provides all information required for the aircraft development, operation and certification. Typically the execution of a FTC encompasses three major systems as follows: Flight Test Instrumentation System (FTI) that is basically a measurement system; Real-Time Telemetry Link (RTL); and Ground Telemetry System (GTS). At the early days, for the development of small aircrafts (i.e. Fighter), the primary source for FTI data was provided by the RTL due to inherent limitations of the open reel airborne data recorders (i.e. media and size), operating under high-dynamics condition. Nowadays with the introduction of solid-state data recording devices, data integrity and reliability is no longer an issue. At the ITC 2010 Blue Ribbon Panel, Mr. Thomas Beard, the executive Director of the Air Force Flight Test Center in Edwards Air Force Base emphasized the need to reduce refly and to improve FTC efficiency. Such statement imposes a new paradigm in Telemetry, which is to improve RTL integrity and reliability level equivalent to the solid-state data recording devices. Therefore the Telemetry community will be able to execute test point validation for refly reduction and quasi realtime data reduction analysis for efficiency improvement. The major solutions that address such issue are Spatial Diversity (SD) architectures and the iNet. The SD solution requires multiple antenna system (which is very expensive) that could still produce ineffective results at high-dynamics test points (e.g. Spin). At the beginning the iNet consortium proposed the usage of TCP protocol for data transmission. Problems associated with TCP limitations such as data latency and overhead lead to the usage of UDP protocol that does not guarantee the packet delivery. To properly address these issues the IPEV R&D group proposes the iPCM Telemetry architecture to be used as RTL. The iPCM uses hybrid architecture for data transmission taking the advantage of legacy digital transmitters combined with iNet-based transceivers to retrieve missing data. The development and the evaluation of iPCM architecture will be executed as a PhD Thesis in ITA University. The expected performance and benefits of iPCM are presented and discussed.
8

DATA LINK LAYER SECURITY PROBLEMS AND SOLUTIONS

Mustafa, Ali, Siddique, Nasir, Zubair, Mubeen January 2015 (has links)
The Open Systems Interconnect Model (OSI) is a conceptual model of networking thatcategorizes network functions into seven layers. It is defined in this model that how layerscommunicate with each other. In this thesis, we address common Layer 2 attacks and theirsolutions. Layer 2 is considered a very weak link in a secure network. If the data is compromisedat Layer 2, it cannot be detected at other layers because each layer works without the knowledgeof other layers. We discuss Layer 2 weakness and vulnerability exploitation tools briefly. It isexplained how an attacker can exploit network by using different attack tools. Our results showthat these attacks are very productive if a network administrator does not implement propersecurity at Layer 2 in the OSI model. We propose solutions to secure Layer 2 devices and thesesolutions are implemented by using attack tools. Security configurations are deployed to combatagainst attacks and protect the integrity, confidentiality, and availability of the network traffic.
9

A Real-Time Bi-Directional Global Positioning System Data Link Over Internet Protocol

Bhattacharya, Sumit 28 September 2005 (has links)
No description available.
10

A Low Rate Data Link For A High Performance Differential Global Positioning System

Needham, Timothy G. 05 August 2008 (has links)
No description available.

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