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Search Results: 1 - 10 of 125561 matches for " Ning Wang "
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A Comparison of the Ghost Cell Technique for Front Tracking Method  [PDF]
Donghong Wang, Yanqing Wang, Ning Zhao
Open Journal of Fluid Dynamics (OJFD) , 2013, DOI: 10.4236/ojfd.2013.33021
Abstract:

The treatment of moving material interfaces and their vicinity is very important for compressible multifluids. In this paper, we propose one type of ghost fluid method based on Riemann solutions for front tracking method. The accuracy of the interface boundary condition is discussed for the gas-gas Riemann problem. It is shown that the solution of the ghost fluid method approximates the exact solution to second-order accuracy in the sense of comparing to the exact solution of a Riemann problem at the material interface. Numerical examples suggest that the present scheme is able to handle multifluids problems with large density differences and has the property of reduced conservation error.

An Incremental-Selective Cooperative Relaying Scheme with Best Relay Selection in WSN80002  [PDF]
Shaoqing Wang, Hanlin Yang, Ning Zhou, An Wang
Journal of Computer and Communications (JCC) , 2015, DOI: 10.4236/jcc.2015.33018
Abstract:

In wireless sensor networks, the traditional multi-relay incremental cooperative relaying (MIR) scheme could improve the system throughput over the fading channel enormously by exploiting multiple relay nodes to retransmit the copy of the source packet to the destination in turn, but increase the energy consumption and transmission delay. In order to mitigating the energy consumption and transmission delay, this paper proposes a new cooperative relaying scheme termed as incremental-selective relaying with best-relay selection (ISR), which selects the best relay node from the candidate relays to retransmit the packet to the destination only when the direct transmission between the source and the destination is not successful. Expressions of normalized throughput, normalized delay and energy efficiency for the ISR and MIR systems are derived respectively and their performances are compared through simulations. The results show that normalized throughput, normalized delay and energy efficiency for the ISR system all outperform the corresponding performances of the MIR system. Especially, there are different the optimal number of relays which can maximize the energy efficiency of system.

Normality of the Stock Index Futures of China  [PDF]
Ning Wang, Yibo Chen, Bo Wang
Journal of Mathematical Finance (JMF) , 2018, DOI: 10.4236/jmf.2018.81007
Abstract: In this paper, we test the null hypothesis that the prices of stock index futures of China follow a random-walk process. Five hypothesis tests are applied to test the random-walk hypothesis (RWH). Each test uses both inter-day and intra-day returns. Compared with inter-day analysis, test results on intra-day data can describe the movements of intra-day markets more effectively, because intra-day analysis eliminates overnight news propagation, thus generating more precise conclusions on the intra-day market for intra-day traders. Three out of the five tests reject the RWH, whereas the other two cannot reject the RWH. Overall, the market is not fully efficient.
{N,N′-Bis[1-(2-pyridyl)ethylidene]propane-1,2-diamine}bis(thiocyanato-κN)nickel(II)
Ning Wang
Acta Crystallographica Section E , 2010, DOI: 10.1107/s1600536810029454
Abstract: In the title complex, [Ni(NCS)2(C17H20N4)], the Ni2+ ion (site symmetry 2) is coordinated by the N,N,N,N-tetradentate Schiff base ligand and two thiocyanate ligands, forming a distorted NiN6 octahedral geometry, with the thiocyanate N atoms in a trans orientation. The pendant methyl group of the central propane-1,2-diamine fragment of the ligand is statistically disordered over two sets of positions. In the crystal, weak aromatic π–π stacking between pyridine rings [centroid–centroid separation = 3.7081 (17) ] may help to establish the packing.
Bis[2-(1-iminoethyl)phenolato-κ2N,O]nickel(II)
Ning Wang
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536811051476
Abstract: There are one and a half independent molecules in the asymmetric unit of the title compound, [Ni(C8H8NO)2], one of which is situated on an inversion center. In both molecules, the NiII ion is coordinated by two O and two N atoms from two Schiff base ligands in an approximate square-planar geometry. Intermolecular N—H...O hydrogen bonds link three molecules into centrosymmetric trimer. The crystal packing exhibits weak intermolecular C—H...O hydrogen bonds and voids of 37 3.
Formal Semantics of OWL-S with Rewrite Logic  [PDF]
Ning Huang, Xiaojuan Wang, Camilo Rocha
Journal of Software Engineering and Applications (JSEA) , 2009, DOI: 10.4236/jsea.2009.21004
Abstract: SOA is built upon and evolving from older concepts of distributed computing and modular programming, OWL-S plays a key role in describing behaviors of web services, which are the essential of the SOA software. Although OWL-S has given semantics to concepts by ontology technology, it gives no semantics to control-flow and data-flow. This paper presents a formal semantics framework for OWL-S sub-set, including its abstraction, syntax, static and dynamic seman-tics by rewrite logic. Details of a consistent transformation from OWL-S SOS of control-flow to corresponding rules and equations, and dataflow semantics including “Precondition”, “Result” and “Binding” etc. are explained. This paper provides a possibility for formal verification and reliability evaluation of software based on SOA.
Design of Fading Channel Simulator Based on IIR Filter Using Genetic Algorithm  [PDF]
Haofeng Wang, Siwei Du, Ning Guan
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2017, DOI: 10.4236/ijcns.2017.105B010
Abstract:
This article designs a Rayleigh fading channel simulator using IIR filter (called Doppler filter), which is used to approximate the Jakes Doppler spectrum. We mainly focus on the design of Doppler filter and model it as an optimization problem. Non-convexity of the problem is proved in this paper and genetic algorithm (GA) is used to optimize it, which has never been used before in this area. Simulation result shows that GA converges at the solution corresponding to very accurate approximation of Jakes PSD. Finally, several statistical characteristics of the simulator are verified, including correlation functions and level-crossing rate (LCR), all of which match the theoretical predictions pretty well.
An Application of Context Middleware Based on Fuzzy Logic for Wireless Sensor Networks  [PDF]
Ye NING, Ruchuan WANG, Shouming MA, Zhili WANG
Wireless Sensor Network (WSN) , 2009, DOI: 10.4236/wsn.2009.15045
Abstract: The research of context-aware computing based on wireless sensor network (WSN) aims at intelligently connecting computers, users, and environment. So its application system should be flexibly adaptable to dynamic changes of context and application requirements and proactively provides the information satisfied with current context for users. The middleware can be very effective to provide the support runtime services for context-aware computing. In this paper we propose middleware architecture for context processing. This architecture is based on fuzzy logic control (FLC) system for context reasoning and sensor fusion. We propose a formal context representation model in which a user’s context is described by a set of roles and relations correspond to a context space. A middleware prototype has been developed, which detect tourist’ physical context and provide reminding. The experiments prove that the model and approach proposed are feasible.
Efficient Clustering Routing Algorithm Based on Opportunistic Routing  [PDF]
Fan Wang, Yan Yang, Kunpeng Wang, Xiaopeng Hu, Ning Zhang
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2016, DOI: 10.4236/ijcns.2016.95019
Abstract:

Based on the analysis of the existing classic clustering routing algorithm HEED, this paper proposes an efficient dynamic clustering routing algorithm ED-HEED. In the cluster selection process, in order to optimize the network topology and select more proper nodes as the cluster head, the proposed clustering algorithm considers the shortest path prediction of the node to the destination sink and the congestion situation. In the data transmission procedure, the high-efficiency CEDOR opportunistic routing algorithm is applied into the ED-HEED as the data transmission mode between cluster headers. A novel adaptive dynamic clustering mechanism is also considered into the algorithm, as well as the data redundancy and security control. Our Simulation demonstrates that the ED-HEED algorithm can reduce the energy consumption, prolong the network life and keep the security and availability of the network compared with the HEED algorithm.

A Highly Compatible Circular-Shifting Network for Partially Parallel QC-LDPC Decoder  [PDF]
Yanzhi Wang, Zhenzhi Wu, Peipei Liu, Ning Guan, Hua Wang
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2017, DOI: 10.4236/ijcns.2017.105B003
Abstract:
The conventional methodology for designing QC-LDPC decoders is applied for fixed configurations used in wireless communication standards, and the supported largest expansion factor Z (the parallelism of the layered decoding) is a fixed number. In this paper, we study the circular-shifting network for decoding LDPC codes with arbitrary Z factor, especially for decoding large Z (Z P) codes, where P is the decoder parallelism. By buffering the P-length slices from the memory, and assembling the shifted slices in a fixed routine, the P-parallelism shift network can process Z-parallelism circular-shifting tasks. The implementation results show that the proposed network for arbitrary sized data shifting consumes only one times of additional resource cost compared to the traditional solution for only maximum P sized data shifting, and achieves significant saving on area and routing complexity.
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