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Search Results: 1 - 10 of 8068 matches for " Demin Cui "
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The Next-Hop Node Selection Based GPSR in Vehicular Ad Hoc Networks  [PDF]
Zhaoyuan Cui, Demin Li, Guanglin Zhang, Chang Guo, Yong Sheng
Journal of Computer and Communications (JCC) , 2016, DOI: 10.4236/jcc.2016.410005
Abstract: Vehicular Ad hoc Networks (VANETs) which is a special form of Mobile Ad hoc Networks (MANETs) has promising application prospects in the future. Due to the rapid changing of topology structure, how to find a route which can guarantee Quality of Service (QoS) is an important issue in VANETs. This paper presents an improved Greedy Perimeter Stateless Routing (GPSR) protocol based on our proposed next-hop node selection mechanism. Firstly, we define the link reliability in two cases which take the movement direction angle between two vehicles into consideration. Then we propose a next-hop node selection mechanism based on a weighted function which consists of link reliability between the sender node and next-hop candidate node, distance between next-hop candidate node and the destination, movement direction angle of next-hop candidate node. At last, an improved GPSR protocol is proposed based on the next-hop node selection mechanism. Simulation results are presented to evaluate the performance of the improved GPSR protocol, which shows that the performance including packet delivery ratio and average end-to-end delay of the proposed protocol is better in some situations.
An Integrated Control Strategy Adopting Droop Control with Virtual Inductance in Microgrid  [PDF]
Jianjun Su, Jieyun Zheng, Demin Cui, Xiaobo Li, Zhijian Hu, Chengxue Zhang
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.51B008
Abstract: As there exists sorts of distributed generators in microgrid, an integrated control strategy containing different control methods against corresponding generators should be applied. The strategy in this paper involves PQ control and droop control methods. The former aims at letting generators like PV output maximum power. The latter stems from inverter parallel technique and applies to controlling generators which can keep the network voltage steady to make the parallel system reach the minimum circulation point. Due to the unworthiness of droop control applied in low-voltage microgrid of which the impedance ratio is rather high, the paper adopts the droop control introducing virtual generator and virtual impedance. Based on theoretical analysis, simulation in Matlab is also implemented to verify the feasibility of the strategy.
New Method of Measuring the Positive-sequence Capacitance of T-connection Transmission Lines  [PDF]
Yuansen Zhang, Demin Cui, Qingtao Cao, Yongqiang Chai, Peng Liu, Xiaobo Li, Zhijian Hu, Chuanqi Li, Chengxue Zhang
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B180
Abstract:

A novel method of measuring the positive-sequence capacitance of T-connection transmission lines is proposed. The mathematical model of the new method is explained in detail. In order to obtain enough independent equations, three independent operation modes of T-connection transmission lines during the line measurement are introduced. The digital simulation results and field measurement results are shown. The simulation and measurement results have validated that the new method can meet the needs of measuring the positive-sequence capacitance of T-connection transmission lines. This method has been implemented in the newly developed measurement instrument.

Simulation on Calculation Accuracy of Three Methods for Live Line Measuring the Parameters of Transmission Lines with Mutual Inductance  [PDF]
Jianjun Su, Ronghua Zhang, Demin Cui, Yongqiang Chai, Xiaobo Li, Chengxue Zhang, Peiyan Li, Zhijian Hu, Yingying Hu
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B272
Abstract:

Live line measurement methods can reduce the loss of power outages and eliminate interference. There are three live line measurement methods including integral method, differential method and algebraic method. A simulation model of two coupled parallel transmission lines spanning on the same towers is built in PSCAD and the calculation errors of these three methods are compared with different sampling frequencies by using of Matlab. The effect of harmonic on calculation is also involved. The simulation results indicate that harmonic has the least effect on the algebraic method which provides stable result and small error.

Fracture and Damage Behaviors of Concrete in the Fractal Space  [PDF]
Heng Zhang, Demin Wei
Journal of Modern Physics (JMP) , 2010, DOI: 10.4236/jmp.2010.11006
Abstract: The fracture toughness, the driving force and the fracture energy for an infinite plate with a fractal crack are investigated in the fractal space in this work. The perimeter-area relation is adopted to derive the transforma-tion rule between damage variables in the fractal space and Euclidean space. A plasticity yield criterion is introduced and a damage variable tensor is decomposed into tensile and compressive components to describe the distinct behaviors in tension and compression. A plastic damage constitutive model for concrete in the Euclidean space is developed and generalized to fractal case according to the transformation rule of damage variables. Numerical calculations of the present model with and without fractal are conducted and compared with experimental data to verify the efficiency of this model and show the necessity of considering the fractal effect in the constitutive model of concrete. The structural response and mesh sensitivity of a notched unre-inforced concrete beam under 3-point bending test are theoretical studied and show good agreement with the experimental data.
Comparative analgesic effect of Ligusticum chuanxiong pieces and its products in mice
GAO Demin,XU Lingchuan
Pharmacognosy Magazine , 2010,
Abstract: The present study was undertaken with the objective of finding out the comparative analgesic effect of Ligusticum chuanxiong (LC) pieces decoction, LC formula granule decoction, liquored LC pieces decoction and liquored LC formula granule decoction. The analgesic effects were analyzed using the hot plate and acetic-induced writhing test in mice, and antidysmenorrheic effect was observed with primary dysmenorrhea model. The results showed that four kinds of LC decoction had definite effect in delaying incubation period and decreasing the writhing frequency within 30 min. They also effectively relieved dysmenorrhea. Moreover, liquored LC had better analgesic effect than crude LC in four decoctions.
The Infective endocarditis (prevention, diagnosis criteria and treatment): key points 2010
A.A. Demin
Rational Pharmacotherapy in Cardiology , 2010,
Abstract: Key positions of Guidelines on the prevention, diagnosis, and treatment of infective endocarditis issued by the Task Force of ESC in 2009 are explained in the comments. Recent opinions on these items are presented.
Analysis of efficacy of SGLT2 inhibitors using semi-mechanistic model
Oleg Demin Jr
Frontiers in Pharmacology , 2014, DOI: 10.3389/fphar.2014.00218
Abstract: Renal sodium-dependent glucose co-transporter 2 (SGLT2) is one of the most promising targets for the treatment of type 2 diabetes. Two SGLT2 inhibitors, dapagliflozin and canagliflozin, have already been approved for use in USA and Europe; several additional compounds are also being developed for this purpose. Based on the in vitro IC50 values and plasma concentration of dapagliflozin measured in clinical trials, the marketed dosage of the drug was expected to almost completely inhibit SGLT2 function and reduce glucose reabsorption by 90%. However, the administration of dapagliflozin resulted in only 30–50% inhibition of reabsorption. This study was aimed at investigating the mechanism underlying the discrepancy between the expected and observed levels of glucose reabsorption. To this end, systems pharmacology models were developed to analyze the time profile of dapagliflozin, canagliflozin, ipragliflozin, empagliflozin, and tofogliflozin in the plasma and urine; their filtration and active secretion from the blood to the renal proximal tubules; reverse reabsorption; urinary excretion; and their inhibitory effect on SGLT2. The model shows that concentration levels of tofogliflozin, ipragliflozin, and empagliflozin are higher than levels of other inhibitors following administration of marketed SGLT2 inhibitors at labeled doses and non-marketed SGLT2 inhibitors at maximal doses (approved for phase 2/3 studies). All the compounds exhibited almost 100% inhibition of SGLT2. Based on the results of our model, two explanations for the observed low efficacy of SGLT2 inhibitors were supported: 1) the site of action of SGLT2 inhibitors is not in the lumen of the kidney’s proximal tubules, but elsewhere (e.g., the kidneys proximal tubule cells); and 2) there are other transporters that could facilitate glucose reabsorption under the conditions of SGLT2 inhibition (e.g., other transporters of SGLT family).
Geometry Method for the Rotating Navier-Stokes Equations With Complex Boundary and the Bi-Parallel Algorithm
Kaitai Li,Demin Liu
Mathematics , 2011,
Abstract: In this paper, a new algorithm based on differential geometry viewpoint to solve the 3D rotating Navier-Stokes equations with complex Boundary is proposed, which is called Bi-parallel algorithm. For xample, it can be applied to passage flow between two blades in impeller and circulation flow through aircrafts with complex geometric shape of boundary. Assume that a domain in $R^3$ can be decomposed into a series sub-domain, which is called "flow layer", by a series smooth surface $\Im_k, k=1,...,M$. Applying differential geometry method, the 3D Navier-Stokes operator can be split into two kind of operator: the "Membrane Operator" on the tangent space at the surface $\Im_k$ and the "Bending Operator" along the transverse direction. The Bending Operators are approximated by the finite different quotients and restricted the 3D Naver-Stokes equations on the interface surface $\Im_k$, a Bi-Parallel algorithm can be constructed along two directors: "Bending" direction and "Membrane" directors. The advantages of the method are that: (1) it can improve the accuracy of approximate solution caused of irregular mesh nearly the complex boundary; (2) it can overcome the numerically effects of boundary layer, whic is a good boundary layer numerical method; (3) it is sufficiency to solve a two dimensional sub-problem without solving 3D sub-problem.
A Cooperative Location Management Scheme for Mobile Ad Hoc Networks  [PDF]
Demin LI, Jiacun WANG, Liping ZHANG, Hao LI, Jie ZHOU
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2009, DOI: 10.4236/ijcns.2009.28084
Abstract: A mobile ad hoc network (MANET) is a kind of wireless ad hoc network. It is a self-configuring network of mobile routers connected by wireless links. Since MANETs do not have a fixed infrastructure, it is a chal-lenge to design a location management scheme that is both scalable and cost-efficient. In this paper, we propose a cooperative location management scheme, called CooLMS, for MANETs. CooLMS combines the strength of grid based location management and pointer forwarding strategy to achieve high scalability and low signaling cost. An indepth formal analysis of the location management cost of CooLMS is presented. In particular, the total location management cost of mobile nodes moving at variable velocity is estimated using the Gauss_Markov mobility model for the correlation of mobility velocities. Simulation results show CooLMS performs better than other schemes under certain circumstances.
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