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Search Results: 1 - 10 of 41553 matches for " Lei Sun "
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A Study of the Joint Advertising Channels  [PDF]
Ming LEI, Shuguang SUN, Dan YANG
Journal of Service Science and Management (JSSM) , 2009, DOI: 10.4236/jssm.2009.24050
Abstract: The study of joint advertising channels decision-making is a very difficult issue. It mainly focuses on ads investment game between a manufacturer and a retailer in a vertical supply chain. With the rise of the game theory, scholars have been starting to investigate this issue in the frame of game theory in recent years. The paper improves the existing models and introduces single-period and multi-period modified models. The paper obtains the closed-form solutions to the single-period model and the simulation results of the multi-period model. We also examine the implications of these results and obtain some insights into the real practice.
Adsorption of Methylene Blue by NaOH-modified Dead Leaves of Plane Trees  [PDF]
Lei Gong, Wei Sun, Lingying Kong
Computational Water, Energy, and Environmental Engineering (CWEEE) , 2013, DOI: 10.4236/cweee.2013.22B003
Abstract:

NaOH-modified dead leaves of plane trees were used as bioadsorbent to remove methylene blue (MB) from aqueous solution. Variable influencing factors, including contact time, temperature, initial MB concentration and pH were studied through single-factor experiments. The results showed that the initial concentration 100 mg/L, bioadsorbent of 2.5 g/L, pH of 7, room temperature were the best adsorption conditions. The NaOH-modified bioadsorbent had a high adsorption capacity for MB, and its saturated extent of adsorption was 203.28 mg/g, which was higher than the un-modified dead leaves (145.62 mg/g) and some other bioadsorbents. Finally, adsorption kinetics and isotherms were discussed, suggesting that the Langmuir isotherm model and Pseudo-second order kinetics were fitted well with the adsorption process.

Continuously Essential Set of Nash Equilibria for n-person Noncooperative Games
Lei Sun,Xiaodong Fan
Information Technology Journal , 2013,
Abstract: This study has established a new perturbed game of the n-person noncooperative game. A new definition of stable set of Nash equilibria is introduced in this way, which called continuously essential set. This study showed that there exists at least one continuously essential component of Nash equilibria for each perturbed game. As a subset of hyperstable set and quasistable set and so on, the continuously essential set is a further refinement of the Nash equilibria.
Optimal Inventory Modeling of Multi-ECHELON System for Aircraft Spares Parts
Lei Sun,Hongfu Zuo
Information Technology Journal , 2013,
Abstract: Owing to the expensive and sporadic demand nature of aircraft spare parts, the stock level of spare parts was difficult to confirm. How to maximize the availability of the aircraft fleet with cost constraint for spare parts was an important issue for airlines. A multi-ECHELON inventory model based on METRIC (Multi-ECHELON technology for recoverable items control) was proposed by allocating spare parts among the bases of airlines in this study. The model based on system approach instead of item approach to determine aircraft spare parts stock level in a multi-ECHELON system. First, the key system measure was selected, then, the Negative binomial distribution was employed to more accurately reflect the variance in part failure processes when the value of variance-to-mean ratio was bigger than one, Next, the marginal analysis method was applied to find the optimal position of spare parts among bases and depot, finally, two examples were given and the first one showed that the negative binomial distribution was more reasonable than Poisson distribution to describe the non-stationary demand process. The second one showed that the models in this paper were engineering applicability for airlines and could provide an effective theoretical and technical support.
New Nonsmooth Equations-Based Algorithms for -Norm Minimization and Applications
Lei Wu,Zhe Sun
Journal of Applied Mathematics , 2012, DOI: 10.1155/2012/139609
Abstract: Recently, Xiao et al. proposed a nonsmooth equations-based method to solve the -norm minimization problem (2011). The advantage of this method is its simplicity and lower storage. In this paper, based on new nonsmooth equations reformulation, we investigate new nonsmooth equations-based algorithms for solving -norm minimization problems. Under mild conditions, we show that the proposed algorithms are globally convergent. The preliminary numerical results demonstrate the effectiveness of the proposed algorithms. 1. Introduction We consider the -norm minimization problem where , , , and is a nonnegative parameter. Throughout the paper, we use and to denote the Euclidean norm and the -norm of vector , respectively. Problem (1.1) has many important practical applications, particularly in compressed sensing (abbreviated as CS) [1] and image restoration [2]. It can also be viewed as a regularization technique to overcome the ill-conditioned, or even singular, nature of matrix , when trying to infer from noiseless observations or from noisy observations , where is the white Gaussian noise of variance [3–5]. The convex optimization problem (1.1) can be cast as a second-order cone programming problem and thus could be solved via interior point methods. However, in many applications, the problem is not only large scale but also involves dense matrix data, which often precludes the use and potential advantage of sophisticated interior point methods. This motivated the search of simpler first-order algorithms for solving (1.1), where the dominant computational effort is a relatively cheap matrix-vector multiplication involving and . In the past few years, several first-order algorithms have been proposed. One of the most popular algorithms falls into the iterative shrinkage/thresholding (IST) class [6, 7]. It was first designed for wavelet-based image deconvolution problems [8] and analyzed subsequently by many authors, see, for example, [9–11]. Figueiredo et al. [12] studied the gradient projection and Barzilai-Borwein method [13] (denoted by GPSR-BB) for solving (1.1). They reformulated problem (1.1) as a box-constrained quadratic program and solved it by a gradient projection and Barzilai-Borwein method. Wright et al. [14] presented sparse reconstruction algorithm (denoted by SPARSA) to solve (1.1). Yun and Toh [15] proposed a block coordinate gradient descent algorithm for solving (1.1). Yang and Zhang [16] investigated alternating direction algorithms for solving (1.1). Quite recently, Xiao et al. [17] developed a nonsmooth equations-based algorithm (called
Bimodular high temperature planar oxygen gas sensor
Xiangcheng Sun,Yu Lei
Frontiers in Chemistry , 2014, DOI: 10.3389/fchem.2014.00057
Abstract: A bimodular planar O2 sensor was fabricated using NiO nanoparticles (NPs) thin film coated yttria-stabilized zirconia (YSZ) substrate. The thin film was prepared by radio frequency (r.f.) magnetron sputtering of NiO on YSZ substrate, followed by high temperature sintering. The surface morphology of NiO NPs film was characterized by atomic force microscope (AFM) and scanning electron microscope (SEM). X-ray diffraction (XRD) patterns of NiO NPs thin film before and after high temperature O2 sensing demonstrated that the sensing material possesses a good chemical and structure stability. The oxygen detection experiments were performed at 500, 600, and 800°C using the as-prepared bimodular O2 sensor under both potentiometric and resistance modules. For the potentiometric module, a linear relationship between electromotive force (EMF) output of the sensor and the logarithm of O2 concentration was observed at each operating temperature, following the Nernst law. For the resistance module, the logarithm of electrical conductivity was proportional to the logarithm of oxygen concentration at each operating temperature, in good agreement with literature report. In addition, this bimodular sensor shows sensitive, reproducible and reversible response to oxygen under both sensing modules. Integration of two sensing modules into one sensor could greatly enrich the information output and would open a new venue in the development of high temperature gas sensors.
Quantized CSI-Based Tomlinson-Harashima Precoding in Multiuser MIMO Systems
Liang Sun,Ming Lei
Mathematics , 2014,
Abstract: This paper considers the implementation of Tomlinson-Harashima (TH) precoding for multiuser MIMO systems based on quantized channel state information (CSI) at the transmitter side. Compared with the results in [1], our scheme applies to more general system setting where the number of users in the system can be less than or equal to the number of transmit antennas. We also study the achievable average sum rate of the proposed quantized CSI-based TH precoding scheme. The expressions of the upper bounds on both the average sum rate of the systems with quantized CSI and the mean loss in average sum rate due to CSI quantization are derived. We also present some numerical results. The results show that the nonlinear TH precoding can achieve much better performance than that of linear zero-forcing precoding for both perfect CSI and quantized CSI cases. In addition, our derived upper bound on the mean rate loss for TH precoding converges to the true rate loss faster than that of zeroforcing precoding obtained in [2] as the number of feedback bits becomes large. Both the analytical and numerical results show that nonlinear precoding suffers from imperfect CSI more than linear precoding does.
Design of New-generation Electric Vehicle Terminal  [PDF]
Lei Li, Xin Lu, Jiasheng He, Zhe Sun, Guang Yang
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B258
Abstract:

EVT (electric vehicle terminal) has played an important role in EV (electric vehicle) operation. Based on research status of vehicle terminal, EVT brought about in the future should have the following functions: (1) fundamental functions, including real-time monitoring of batteries, guidance in station, position guidance of charging/battery-swap infrastructures, communication with OMS (operation and management system), and so on; (2) advanced functions, including but not limited to multi-media entertainment, subscribing and payment for charging/battery-swap, identification, and safety control during driving. Complete design of new-generation EVT in software structure and hardware architecture is proposed; a new idea of the application of EVT in EV industry is put forward.

A Chain Routing Algorithm Based on Traffic Prediction in Wireless Sensor Networks  [PDF]
Yi Sun, Lei Xu, Xin Wu, Minxuan Shen
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.53B2092
Abstract:

As a representative of chain-based protocol in Wireless Sensor Networks (WSNs), EEPB is an elegant solution on energy efficiency. However, in the latter part of the operation of the network, there is still a big problem: reserving energy of the node frequently presents the incapacity of directly communicating with the base station, at the same time capacity of data acquisition and transmission as normal nodes. If these nodes were selected as LEADER nodes, that will accelerate the death process and unevenness of energy consumption distribution among nodes.This paper proposed a chain routing algorithm based ontraffic prediction model (CRTP).The novel algorithmdesigns a threshold judgment method through introducing the traffic prediction model in the process of election of LEADER node. The process can be dynamically adjusted according to the flow forecasting. Therefore, this algorithm lets the energy consumption tend-ing to keep at same level. Simulation results show that CRTP has superior performance over EEPB in terms of balanced network energy consumption and the prolonged network life.

A Semi-Implicit Scheme of Lattice Boltzmann Method for Two Dimensional Cavity Flow Simulation  [PDF]
Lei Zhang, Jun Yao, Hai Sun, Jianguang Zhang
Open Journal of Fluid Dynamics (OJFD) , 2015, DOI: 10.4236/ojfd.2015.51002
Abstract: The calculation sequence of collision, propagation and macroscopic variables is not very clear in lattice Boltzmann method (LBM) code implementation. According to the definition, three steps should be computed on all nodes respectively, which mean three loops are needed. While the “pull” scheme makes the only one loop possible for coding, this is called semi-implicit scheme in this study. The accuracy and efficiency of semi-implicit scheme are discussed in detail through the simulation of lid-driven cavity flow. Non-equilibrium extrapolation scheme is adopted on the boundary of simulation area. The results are compared with two classic articles, which show that semi-implicit scheme has good agreement with the classic scheme. When Re is less than 3000, the iterations steps of semi-scheme can be decreased by about 30% though comparing the semi-implicit scheme with standard scheme containing three loops. As the Re increases into more than 3400, the standard scheme is not converged. On the contrary, the iterations of semi-implicit scheme are approximately linear to Re.
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