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In this paper, we take a close look to understand the cloud-based file synchronization and collaboration systems. Using the popular Dropbox as a case study, our measurement reveals its cascaded computation and communication operations that are far more complicated than those in conventional file hosting. We show that this serial design is necessary for the cloud deployment, which effectively avoids...
The leaderless synchronization of multiple agents modeled by nonlinear Euler-Lagrange equation is investigated under limited directed communication. An adaptive cooperative control law is proposed to synchronize the whole group with parametric uncertainties. It is proved that synchronization can be achieved if and only if the communication graph has a directed spanning tree. Lyapunov theory and eigenvalue-based...
Powered by cloud computing, Dropbox not only provides reliable file storage but also enables effective file synchronization and user collaboration. This new generation of service, beyond conventional client/server or peer-to-peer file hosting with storage only, has attracted a vast number of Internet users. It is however known that the synchronization delay of Dropbox-like systems is increasing with...
Synchronization is of fundamental importance for wireless cellular systems, especially for orthogonal frequency division multiplexing (OFDM) based systems. In this paper, we investigate carrier frequency offset (CFO) estimation in the initial synchronization for the downlink of 3GPP-long term evolution (3GPP-LTE). Firstly, three traditional CFO estimation schemes including the primary synchronization...
Existing time synchronization algorithms and protocols mostly focus on improving the synchronization accuracy. However, they usually require frequent resynchronization to keep designed precision in actual applications, which leads to high energy consumption and heavy traffic load. This paper presents a Prediction based Long-cycle Time Synchronization algorithm (PLTS), which puts emphasis on reducing...
Synchronization and cell search are of fundamental importance for the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) downlink system. In LTE, the secondary synchronization channel (S-SCH) contains the information of 10 ms frame timing and cell identity group. Hence, it is important for user equipment (UE) to detect S-SCH effectively. In this paper, we present a low computational...
For the practical application of synchronous acquisition of digital signals on many kinds of circuit boards, this paper, based on NI-TCLK (Trigger clock) synchronization technology, the modular hardware as the circuit board based on PXI (PCI extensions for Instrumentation) bus, as well as the modular software as NI-LABVIEW, a multi-module synchronic data acquisition system is developed. Accordingly,...
We consider serially-concatenated coding schemes over channels impaired by insertion, deletion, and substitution errors. Specifically, we focus on the interleaved concatenation of an outer channel code with error-correction capabilities and an inner marker code with synchronization capabilities. To limit the decoding latency, marker code-based synchronization is performed only once per received packet,...
In this paper, we use virtual instruments (VI) and commercial off-the-shelf (COTS) technique to construct a portable general automatic test system (ATS). The system's function were realized by using PXI based modular architecture in its automatic test equipment (ATE). While its test program set (TPS) was compiled on the basis of the graphical development platform - LabVIEW8.2. By using powerful data...
A new centralized and decentralized mixture control via virtual structure (VS) approach for the large number of spacecrafts formation flying is presented in this paper. To describe the formation clearly, the entire formation is considered as a main VS including several sub-VSs and every sub-VS includes several single spacecrafts. In this mixture control architecture, the decentralized architecture...
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