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A group of multiple peers are required to cooperate with each other in distributed peer-to-peer (P2P) applications. Here, messages have to be causally delivered to every peer. In our approach to realizing a scalable P2P group, messages are ordered by taking advantage of linear time (LT) and physical time (PT) since message length is O(1). Here, each peer has to hold information on clock accuracy of...
At present, Machine-to-Machine (M2M) communication have become new services with large market potential, and show quite different characters compared with the traditional Human-to-Human (H2H) communications. It is a big challenge to guarantee the Quality of Service (QoS) for M2M services in traditional telecomm. network. This paper focuses on the QoS categorization of M2M services. Based on the analysis...
In data management for large-scale applications, challenges arise in regard to the decentralization of the application and to an increasing number of failures. A consequence of these conditions is an increasing retrieval time, inaccurate results and higher network consumption. A solution to restrain an increasing retrieval time and an increasing number of messages is the introduction of approximate...
As one of the key technologies in multi-domain optical networks'(MDONs) research, topology aggregation(TA) plays an important role in its security and scalability requirements. A novel TA algorithm applied to the MDONs with multiple quality of service(QoS) parameters constraints is proposed in this paper. The proposed algorithm captures the actual topology resources about the network more accurately...
In this study, we present an experimental study of the time reversal (TR) technique in a single-input single-output configuration over the frequency range of 2-12 GHz. Our TR implementation is demonstrated to have high accuracy by comparing experimental TR traces with theoretical traces computed from the measured channel response. A special emphasis of this work is to investigate the effectiveness...
The ionospheric error is an important error source for GPS user. In order to eliminate this error, using a good method for correcting ionospheric error is necessary. In this paper, the author analyzed the virtue and flaw of these correction methods, used a method of dual-frequency pseudo range and carrier phase measurement to eliminate the ionospheric error of observation path, estimated the accuracy...
A hardware-based solution of precise time synchronization over Ethernet was proposed for Networked Control System (NCS). Using Field-programmable Gate Array (FPGA), hardware-based solution was designed for implementing time synchronization protocol defined in IEEE 1588. Timestamp capture, oscillator frequency compensation, time synchronization and etc., were all coded with Very High Speed Integrated...
As the modern electronic system becomes more complicated, the new situations and works require a data acquisition system with a more accurate time parameter. Time delay between channels of high-speed data acquisition system is an important time parameter to estimate and adjust. In high-speed data acquisition system, the ADC data output time is not fixed, and may lead to the delay time of each acquisition...
Existing in-network query processing techniques are categorized as approximation and aggregation based approaches. The former achieves lower query response delay at the expense of accuracy, while the latter reduces query response inaccuracy by executing queries at the actual sensor nodes resulting in longer delay. In this paper, we propose a query processing framework which is delay as well as accuracy...
As one of the key technologies in Ad hoc networks, clock synchronization is the prerequisite of important network functions. Main consideration in clock synchronization are the choice of global clock and the accuracy, in which the existing clock synchronization methods still suffer lack. In this paper, the network delay is measured in networking process, and the network nodes complete synchronization...
To achieve natural and smooth control of prostheses, Electromyographic (EMG) signals have been investigated for decoding user intent. However, EMG signals can be easily contaminated by diverse disturbances, leading to errors in user intent recognition and threatening the safety of prostheses users. To address this problem, we propose a trust sensor interface (TSI) that contains 2 modules: (1) abnormality...
There is an increasing demand for the accurate travel time, however the inadequacy of traditional travel time is highlighted on urban streets relative to freeways. In this paper, the travel time on urban road network, of which the traffic lights result in much random control delay times, is divided into two components: link valid travel time (LVTT) and intersection delay time (IDT). What is more,...
EGNOS corrections are distributed over most European countries. Unfortunately, the current ground infrastructure saves the correction accuracy only for limited area of Europe. On the edge of that area, the usefulness of the EGNOS corrections is questionable. That problem occurs in Poland. In Space Research Centre there were prepared the analyses of possibilities of extension EGNOS ionospheric correction...
The PARIS in orbit demonstrator is a novel altimeter concept recently proposed by the European Space Agency with has the objective of observing ocean mesoscale features with an expected sea surface height estimation accuracy of about 20 cm and unprecedented simultaneous spatial-temporal sampling of the ocean. This altimeter is based on the well known PARIS (also defined as GNSS-R) technique, which...
Clock synchronization is becoming an increasingly important characteristic of modern wide area monitoring and control systems such as the power grid. It provides an opportunity to coordinate control actions and measurement instants across hundreds of miles and numerous network topologies. Devices and networks have advanced to a point where synchronization across a wide area can be achieved within...
Web service composition can make use of distributed services with various functions to accomplish a specific task. Service binding and composition become keywords to service computing. In the context of workflow management, service binding plays an important part in forming a concrete workflow after an abstract one is submitted. Existing research is devoted to selecting a set of servers to run the...
In the summer 2009 NASA Characterization of Arctic Sea Ice Experiment (CASIE09), the microASAR, a small LFMCW SAR, was operated on the NASA Sierra unmanned aerial system (UAS). An overview of the microASAR and its role in CASIE09 are described in [1, 2]. While the limitations in the motion measurements stored with the microASAR data during the CASIE09 mission originally precluded full motion compensation,...
Since July 2010, TerraSAR-X and TanDEM-X jointly acquire interferometric data. Starting their common commissioning phase with a so called pursuit monostatic configuration with 3 seconds time lag between the two passes, they were later put in a close formation in October 2010, acting since then as the first freely configurable bistatic SAR interferometer in space. All operational acquisitions were...
This study design a high precision active radar calibrator (ARC) with programmable echo points which served as control points for both geometric and radiometric calibrations or other applications. The echo delay and Doppler shift of ARC system are fully digitally controlled. Specification and performance of the digital ARC were tested on C-band ERS-2 SAR image. From the experimental results, the FPGA...
In submicron CMOS technology, due to the nonlinearity of the mapping from variation sources to the gate/wire delay, the distribution of the delay is no longer Gaussian. As the widening of process variability calls for accurate non-Gaussian timing models, their deployment requires well-controlled characterization techniques to cope with the complexity and scalability. In this paper, we present a corresponding...
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