Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 53 for “"Time Synchronization"”.
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Virtual time synchronization in distributed database systems
Distributed systems synchronized by Virtual Time have been topics of recent interest. Virtual Time follows an optimistic philosophy relying on rollback for synchronization instead of abortion or blocKing Although many applications have been suggested as candidates for Virtual Time, few were …
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Microsecond Time Synchronization for Computing Fiber Networks
We present a microsecond-accurate time synchronization method and time localization system for a sensor network of spatially-separated, low-power Bluetooth nodes, with the goal of integrating this system into thermally-drawn computing fibers. Each node consists of an nRF54L15 SoC paired with an …
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Analysis Of Time Synchronization Errors In High Data Rate Ultrawideban
… a small absolute number of bits in error in real-time relative to a data rate of hundreds of megabits per second. Our research approach involves managing bit error rates through identifying maximum timing synchronization errors. Thus, it became our research goal to determine the timing accuracies …
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Hardware-assisted timer protocol for high resolution global time synchronization
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.
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Current Implementation of the Flooding Time Synchronization Protocol in Wireless Sensor Networks
Time synchronization is an issue that affects data accuracy within wireless sensor networks (WSNs). This issue is due to the complex nature of the wireless medium and can be mitigated with accurate time synchronization. This research focuses on the Flooding Time Synchronization Protocol (FTSP) …
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Impact of Time Synchronization on Time Aware Shaper Scheduling in Time Sensitive Networks
… widely used. However, for Ethernet to meet these time-sensitive requirements, it must be enhanced. To address this, the IEEE Time-Sensitive Networking (TSN) Task Group has developed standards to extend Ethernet capabilities, including IEEE 802.1Qbv (Time-Aware Shaper, or TAS) for deterministic …
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Remote synchronization method for the quasi-zenith satellite system
This dissertation presents a novel satellite timekeeping system which does not require on-board atomic clocks as used by existing navigation satellite systems such as GPS, GLONASS or the planned GALILEO system. This concept is differentiated by the employment of a synchronization framework combined …
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Performance Analysis of Network Coding Techniques and Resource Allocation Algorithms in Multiuser Wireless Systems
… of the effects of channel estimation errors and time synchronization errors on the performance of different network coding algorithms. It is shown that the performance improvement gained by a relay-based network scheme is significant for small number of users and when the quality of the relay …
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Time keeping in myriad networks : theories, solutions and applications
… sensor networks make extensive use of a common time reference. In this work we address the problem of time dissemination in a packet switched network when the nodes are NOT generally all connected to an accurate, external time reference source. We thoroughly analyze Network Time Protocol - …
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Clock Synchronization for Multihop Wireless Sensor Networks
… in other types of distributed systems, clock synchronization is crucial since by having this service available, several applications such as media access protocols, object tracking, or data fusion, would improve their performance. In this dissertation, we propose a set of algorithms to achieve …
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Improved Terrain Measurement System for Estimation of Global Terrain Features, Surface Roughness, and Texture
… (INS) uncertainty and drift, triggering and time synchronization, system misalignment, and post-processing errors. These errors are addressed, and an improved Vehicle Terrain Measurement System (VTMS) is proposed. A triggering and time synchronization system is developed and insight into the …
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Distributed Grid Analytics Platform (DGAP) for power grid monitoring at the distribution level
… (PMUs) which measure electrical waves with real-time synchronization at widely spread points across the power grid over great benefits. While the PMU device concept is well known in the power industry, the field of power system analysis stands to benefit greatly from using different methods of …
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Temporal synchronization of emulated and simulated models for assessment of networked systems
… hosting it. The accuracy of ascribed virtual time for each emulated execution burst controls the rate of advancement of time perceived by the application, and the overhead associated with time synchronization between emulated and simulated components of the model affects the overall time taken …
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Signal absorption-based range estimator for undersea swarms
… current low-cost solutions, rely on precision time synchronization or two-way communication to compute ranges as part of a full navigation solution. The high cost of reliable Chip-scale atomic clocks (CSACs) and acoustic modems relative to other vehicle components limits large-scale swarms due …
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Open-Source Testbed to Evaluate the Cybersecurity of Phasor Measurement Units
… is the Global Positioning System (GPS) for time synchronization across the board. However, this device has become more susceptible to cyber-attacks such as spoofing. This paper constructs an opensource testbed for the playback of PMU data and testing of cyberattacks on PMUs. Using a local …
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Vision-Based Control and Flight Optimization of a Rotorcraft UAV
… performance are compared to GPS. Accurate time synchronization of the inputs to the position estimation algorithm directly affect the closed-loop stability of the system, proportional with altitude. By identifying the frequency response of each input and adding filters to delay some of the …
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Bring-up of Tello– a dynamic humanoid robot
… for research of teleoperation through real-time synchronization of robots and human pilots, the Tello hardware and software has been engineered to meet the unique high-performance requirements that RoboDesign Lab’s research demands. The electrical design of Tello encompasses an array of …
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Assessment of Cyber Vulnerabilities and Countermeasures for GPS-Time Synchronized Measurements in Smart Grids
… of existing research on cyberattacks against the time-syncrhonized devices such as PMUs and PDCs, along with corresponding countermeasures. We develop a PMU-PDC cybersecurity testbed at Virginia Tech Power and Energy Center (PEC) lab. The testbed is able to simulate real-world GPS-spoofing attack …
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