Li D.,Tsinghua University |
Shang Y.,Tsinghua University |
Shang Y.,Naval Academy of Armament |
Chen C.,Tsinghua University
Proceedings - IEEE INFOCOM | Year: 2014
The explosive expansion of data center sizes aggravates the power consumption and carbon footprint, which has restricted the sustainable growth of cloud services and seriously troubled data center operators. In recent years, plenty of advanced data center network architectures have been proposed. They usually employ richly-connected topologies and multi-path routing to provide high network capacity. Unfortunately, they also undergo inefficient network energy usage during the traffic valley time. To address the problem, many energy-aware flow scheduling algorithms are proposed recently, primarily considering how to aggregate traffic by flexibly choosing the routing paths, with flows fairly sharing the link bandwidths. In this paper, we leverage software defined network (SDN) technique and explore a new solution to energy-aware flow scheduling, i.e., scheduling flows in the time dimension and using exclusive routing (EXR) for each flow, i.e., a flow always exclusively utilizes the links of its routing path. The key insight is that exclusive occupation of link resources usually results in higher link utilization in high-radix data center networks, since each flow does not need to compete for the link bandwidths with others. When scheduling the flows, EXR leaves flexibility to operators to define the priorities of flows, e.g., based on flow size, flow deadline, etc. Extensive simulations and testbed experiments both show that EXR can effectively save network energy compared with the regular fair-sharing routing (FSR), and significantly reduce the average flow completion time if assigning higher scheduling priorities to smaller flows. © 2014 IEEE.
Wang S.,Naval Academy of Armament
2012 2nd International Conference on Remote Sensing, Environment and Transportation Engineering, RSETE 2012 - Proceedings | Year: 2012
A LFM signal detection algorithm based on empirical mode decomposition and Wigner-Hough transform is put forward. The main interference component is found and eliminated through EMD. According to principal signal separation SNR of target component is increased. Through Wigner-Hough transform the energy of LFM signal is concentrated in a peak. Simulation result shows the detection algorithm is effective and target is detected in low SNR. © 2012 IEEE.
Ma S.,Naval Academy of Armament
2014 IEEE International Conference on Signal Processing, Communications and Computing, ICSPCC 2014 | Year: 2014
Aiming at the problem of geomagnetic navigation relying on prior knowledge, this paper present a bio-inspired search navigate model for AUV using geomagnetic information without any priori knowledge. At first, we generalize the biologic navigation process as a convergence of geomagnetic multi-objective from the present point values to object point values problems is inspired by animal geomagnetic navigation behavior. Then, a random walk model is employed to describe AUV motion model and a stress evolution algorithm is used to obtain the parameters of navigate. The interaction between solving the problem of multi-objective navigation with searching navigation motion will guide the AUV tasks to achieve. Finally, simulation results show that the proposed algorithm allows the AUV to navigate efficiently using geomagnetic information without prior map. The proposed algorithm offers insights into the research and application of the biologically inspired geomagnetic navigation. © 2014 IEEE.
Shen J.,Naval Academy of Armament
Binggong Xuebao/Acta Armamentarii | Year: 2015
One of the key techniques of high performance aerial-defense antimissile missile is the design of the guidance law for large maneuvering target. Proportional navigation (PN) guidance is the most widely used law, which is simple and easy to implement on the technology of guidance system. Two generalized algorithms of PN laws with target acceleration compensation and angular acceleration of line-of-sight compensation are presented by taking anti-tactical ballistic missile for example for the limited capture domain of proportion navigation guidance law in capturing the large maneuvering targets. And the results of numerical simulation are analyzed. The results show that the two generalized guidance laws have high accuracy against the maneuvering targets, the required overload of the missile and the miss-distance are small, and the ballistic trajectory are relatively smooth. © 2015, China Ordnance Society. All right reserved.
Wu X.B.,Naval Academy of Armament
Applied Mechanics and Materials | Year: 2013
Analysis of vibration or acoustic signals from rotating machines is often preferred in terms of order spectra rather than frequency spectra. An order spectrum gives the amplitude and/or the phase of the signal as a function of harmonic order of the rotation frequency. Order tracking requires sampling of the vibration signal at constant angular increments and hence at a rate proportional to the shaft speed. Most commercial software for signal processing has the built-in capability of computed order tracking, such as the 7702 order tracking software of B&K Pulse. The order tracking result of interior noise of cab is presented in this paper. From order tracking analysis on the noise of interior cab, we found that the noise mainly comes from the second order excitation of engine, and that the overall noise with respect to engine speed. © (2013) Trans Tech Publications, Switzerland.
Song H.-L.,Naval Academy of Armament
Binggong Xuebao/Acta Armamentarii | Year: 2015
Research on penetration and damage abilities of anti-ship missile is an important basis in studying the demonstration and operational use of weapon systems. The quantitative evaluation penetration and damage abilities of anti-ship missile are achieved by using the multilevel simulation and experimantal technologies. The proposed method is descibed from the aspects of interface design, model analysis, simulation engine and key technologies. The research results can be used for the simulation calculation of operational process and the combat effectiveness estimation of tactical missiles. © 2015, China Ordnance Society. All right reserved.
Zhou L.,Naval Academy of Armament |
Zhou L.,National University of Defense Technology |
Zhou Z.,National University of Defense Technology |
Hu D.,National University of Defense Technology
Neurocomputing | Year: 2013
Most of the current scene classification approaches are based on either low-level or semantic modeling strategies. However, the both strategies have some inherent weaknesses. The low-level modeling based approaches normally classify images into a small number of scene categories and often exhibit poor performance. And the semantic modeling strategies usually bring high computational cost and memory consumption. In this paper, we present a novel approach which retains the advantages of both the low-level and semantic modeling strategies, while at the same time getting over the weaknesses of these two strategies. To represent scene images more effectively, a new visual descriptor called GBPWHGO is introduced. Experimental results on six commonly used data sets demonstrate that our approach performs competitively against previous methods across all data sets, and the GBPWHGO descriptor outperforms the SIFT, LBP and Gist descriptors in scene classification. © 2013 Elsevier B.V.
Cheng H.,Naval Academy of Armament
Applied Mechanics and Materials | Year: 2013
In this paper, the structure of the fuzzy crebellar model articulation controller (FCMAC) neural network was discussed. The FCMAC can improve the accuracy of the CMAC. It also has excellent generalization ability and fault-tolerance ability. The recursive least squares (RLS) algorithm was introduced into the FCMAC. The FCMAC based on RLS algorithm has potential application prospect in the research of modeling and emulation on the complex systems. © (2013) Trans Tech Publications, Switzerland.
Qu Y.,Naval Academy of Armament
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2014
On the basis of a discussion of a few classical avionics architecture types, the major problems in military avionics system structure planning are analyzed, and the characteristics of avionics and mission system for operational support aircraft and its design principles are enumerated. With the latest distributed modular electronics (DME) system technology and architecture framework design method, a tasks and users oriented military avionics architecture of the operational supporting aircraft is constructed. The paper concludes that this is one of the development trends of operational avionics in the future, which utilizes a distributed modular system design scheme to optimize avionics inner functions, and introduces intelligent abnormal structural component technology to integrate military avionics with aerodynamic and general structure design.
Zhang A.M.,Harbin Engineering University |
Cui P.,Harbin Engineering University |
Wang Y.,Naval Academy of Armament
Experiments in Fluids | Year: 2013
Experiments were conducted where the underwater bubble oscillates between two boundaries, a free surface and a horizontal rigid wall. The motion features of both the bubble and the free surface were investigated, via the consideration of two key factors, i.e., the non-dimensional distances from the bubble to the two boundaries. To support the investigation, experiments were conducted in the first place where the bubble oscillates near only one of the two boundaries. Then the other boundary was inserted at different positions to observe the changes in the motion features, including the types, maximum speed and height of the water spike and skirt, the form and speed of the jets, and bubble shapes. Correspondence is found between the motion features of the free surface and different stages of bubble oscillation. Intriguing details such as gas torus around the jet, double jets, bubble entrapment, and microjet of the water spike, etc., are observed. © 2013 Springer-Verlag Berlin Heidelberg.