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Beijing, China

The Beijing University of Posts and Telecommunications is a key national university distinguished by the teaching and research in the field of cable communications, wireless communications, computer, and electronic engineering. BUPT comprises 17 schools, and has an international school program with Queen Mary, University of London.The university was created in 1955 under the Ministry of Posts and Telecommunications and the Communications Department of the General Staff Department of the People's Liberation Army. The name was changed from Institute to University in 1993. It is the most famous and renowned university in the field of telecommunications in China. Wikipedia.

Xinchao Z.,Beijing University of Posts and Telecommunications
Applied Soft Computing Journal | Year: 2010

The canonical particle swarm optimization (PSO) has its own disadvantages, such as the high speed of convergence which often implies a rapid loss of diversity during the optimization process, which inevitably leads to undesirable premature convergence. In order to overcome the disadvantage of PSO, a perturbed particle swarm algorithm (pPSA) is presented based on the new particle updating strategy which is based upon the concept of perturbed global best to deal with the problem of premature convergence and diversity maintenance within the swarm. A linear model and a random model together with the initial max-min model are provided to understand and analyze the uncertainty of perturbed particle updating strategy. pPSA is validated using 12 standard test functions. The preliminary results indicate that pPSO performs much better than PSO both in quality of solutions and robustness and comparable with GCPSO. The experiments confirm us that the perturbed particle updating strategy is an encouraging strategy for stochastic heuristic algorithms and the max-min model is a promising model on the concept of possibility measure. © 2009 Elsevier B.V. All rights reserved. Source

Wang C.,Beijing University of Posts and Telecommunications
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We present an efficient entanglement concentration protocol (ECP) for electron spins based on quantum-dot and microcavity coupled systems. In our ECP, each two-electron spin system in a partially entangled state can be concentrated with the assistance of an ancillary quantum dot and a single photon, not two copies of two-electron spin systems. With current and near-future technology, the locally maximal entanglement of electron spins can be achieved, and our ECP can be used in long-distance quantum communications. © 2012 American Physical Society. Source

Xia J.,Beijing University of Posts and Telecommunications
Telecommunications Policy | Year: 2011

Since the inception of telecom reform in 1994, structural reform has been a main thread surrounding the course of the development of Chinas telecommunications industry. In structuring the 2008 reform and the 2009 3G rollout Chinas government adopted a relatively balanced approach in the hope of creating level-playing-field in 3G era. Nevertheless, due to the presence of substantial switching costs, substitution effects from the present technology mode, that is, 2.5G, the absence of killer applications, among other technological and institutional factors, China may not have a realistic 3G era before moving toward 4G and beyond. At the bare minimum, currently there is a lacking of either adequate technological-push or demand-pull for a full-scale 3G commercializationthere is no sign that this situation will change in the near term. Triggered by recent initiatives of market convergence between the telecommunications, Internet, and cable, a renewed circle of market, and regulatory reform is probably necessary to cast a sounder industry basis for a timing migration toward the next-generation-networks (NGNs). The timing migration toward 4G (and beyond) may provide a chance for a late-mover nation like China to leapfrog its western counterparts in leading the industry in the era of NGNs. To this end, China is confronted with a challenge in re-examining its industry policy as well as technological strategies for a sustainable development in the era of NGNs. This study offers heuristic analysis and insights on the above issues based on archival documents and interviews. While implications are suggested for Chinas circumstances, the Chinese experiences may also be considered by other countries and investors when it comes to 3G (and beyond) policies, regulations, deployments, and evolutions. © 2010 Elsevier Ltd. All rights reserved. Source

Ma J.,Beijing University of Posts and Telecommunications
Optics Express | Year: 2014

The paper has theoretically evaluated a signal-signal beat interference (SSBI) cancellation receiver with the balanced detection (ICRBD) for single sideband optical orthogonal frequency division multiplexing (SSB-OOFDM) signal, which has an improved spectral efficiency (SE) by reducing the guard band (GB) between the OOFDM signal and the optical carrier. The influences of the parameters of the interleaver (IL), the optical coupler (OC), and the balanced photodiodes (BPD) as well as the connecting optical/electrical paths in the ICRBD on the received OFDM signal performance are studied in detail. The theoretical results show that the received OFDM signal and noise power are dependent on the parameters of the devices and their deviation away from the ideal value degrades the performance greatly. Based on the simulation system, the 40Gb/s 16QAM SSB-OOFDM signal with 5GHz GB is converted to the OFDM signal by the ICRBD with the suppressed SSBI. It is observed that (1) the received OFDM signal is insensitive to the deviation of the coupling coefficient of the 3dB OC; (2) the received signal suffers little degradation from the filter outline of the IL if an IL with the bandwidth over 13GHz and 6- or higher-order Gaussian filter is used; (3) the polarization deviation and phase shift between the OOFDM signal and the optical carrier caused by the optical paths between IL and OC have smaller influence on the EVM of the received signal; and (4) although the ICRBD is immune to the polarization deviation of the two recombined SSB-OOFDM signals, the relative time delay between the two optical/electrical paths from the OC to the BPD degrades the received signal seriously. By tuning the time delay in optical or electrical domain to reduce the total relative time delay within 10ps, the EVM maintains below 20%. The simulation results agree well with the theoretical analysis and catch an insight on the mechanism of the ICRBD. © 2014 Optical Society of America. Source

Xinchao Z.,Beijing University of Posts and Telecommunications
Applied Soft Computing Journal | Year: 2011

As we know, simulated annealing algorithm with large neighborhoods has greater probability of arriving at a global optimum than a small one has, if the other conditions, i.e., the initial configuration, initial temperature and temperature decreasing rate, are the same. However, the large neighborhood is not always beneficial, such as when the distance between the global optimum and the current solution is smaller than the step size. Therefore a simulated annealing algorithm with adaptive neighborhood is proposed in this paper. The adaptive non-uniform mutation operation borrowed from evolutionary algorithm is incorporated into simulated annealing for new solution generation. The neighborhood size reduces in probability with the progress of algorithm. It nearly covers the whole search space in the initial stage of algorithm in the sense of probability. The search engine only searches a very local neighborhood at the later stage of algorithm. Why to hybridize non-uniform mutation with simulated annealing is also analyzed and demonstrated. The numerical experiments show that the hybridization can greatly enhance the performance and the reliability of simulated annealing algorithm. Further experiments are made for benchmarks with expanding search domains. Satisfiable results are obtained again even if the variable bounds are enlarged to 1000 times. Theoretical analysis and simulation experiments illustrate the consistent excellent performance and the possible application of nonu-SA algorithm. © 2010 Elsevier B.V. All rights reserved. Source

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