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Search Results: 1 - 10 of 35839 matches for " Dan Zhu "
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Current City Problems in Beijing: Discussion of PM2.5 Related Toxic Air Pollution  [PDF]
Dan Zhu, Michael Kung
Current Urban Studies (CUS) , 2014, DOI: 10.4236/cus.2014.24030
Abstract: Recent reports show that an estimated one-fifth of the world’s population is suffering from toxic air pollution (Qu, 2013; Liu, 2013; Zhou et al., 2013). This is especially evident in China, where PM2.5 covers one-seventh of China’s total territory. In order to combat this disaster, three aspects will be included in this paper to analyze Beijing’s air pollution management through a scientific and philosophical lens for the future human health in China. The first is to address the dangers of PM2.5 to urban environment and city human health. The second approach is to discuss the causing factors of PM2.5 in Beijing, such as coal burning, untreated industrial and vehicular emissions, and urban construction waste. The third step is to state the short and long term effective measures of toxic air pollution of PM2.5 management in big cities of developing countries. Short term recommended plans stop unnecessary urban construction, reduce outdoor exposure, impose a heavy tax, and collect congestion pricing at peak hours. Long term recommended plans promote the coal gasification process, install smoke emission units, improve public transportation, and support clean energy, such as hydropower, wind power, and solar energy. Since current measures are ineffective, taken as a whole, these approaches will be presented to guide local residents, planners, and governors in developing countries to deal with the toxic air pollution for future healthy city management.
New Class of Distortion Risk Measures and Their Tail Asymptotics with Emphasis on VaR  [PDF]
Chuancun Yin, Dan Zhu
Journal of Financial Risk Management (JFRM) , 2018, DOI: 10.4236/jfrm.2018.71002
Abstract: Distortion risk measures are extensively used in finance and insurance applications because of their appealing properties. We present three methods to construct new class of distortion functions and measures. The approach involves the composting methods, the mixing methods and the approach that based on the theory of copula. We also investigate the tail subadditivity for VaR and other distortion risk measures. In particular, we demonstrate that VaR is tail subadditive for the case where the support of risk is bounded. Various examples are also presented to illustrate the results.
Architectural Features of Stilted Buildings of the Tujia People: A Case Study of Ancient Buildings in the Peng Family Village in Western Hubei Province, China  [PDF]
Kui Zhao, William L. Tilson, Dan Zhu
Journal of Building Construction and Planning Research (JBCPR) , 2013, DOI: 10.4236/jbcpr.2013.14014
Abstract: This paper describes and analyzes the stilted buildings of the Tujia people (an ethnic group living in mainland China), a distinctive building style unique to them, from the perspectives of site selection, spatial layout, construction techniques, and cultural inheritance. The cluster of stilted buildings (Diaojiao Lou in Mandarin Pinyin) in the Pengjia Village (meaning most of the villagers share the surname of Peng) is presented as a case study in this paper. The paper makes a case for their preservation as authentic carriers of the Tujia people’s cultural history, which is quickly disappearing due to development pressures. Three preservation strategies are discussed to meet this preservation goal. The first is to provide a detail analysis of the construction language to guarantee authenticity in the documentation, preservation and restoration processes of the stilted buildings. The second is to keep alive the expert knowledge and skill of traditional artisans by involving them in the construction of new structures using diaojiaolou techniques. The third strategy is to encourage local people to “dress-up” discordant buildings constructed mid to late 20th century with well-mannered facades using traditional details such as suspension columns, shuaqi, and six-panel and bang doors. Taking as a whole, these strategies are presented to help local residents, preservation experts, developers and policy makers sustain the irreplaceable cultural heritage and economic independence of the Tujia people.
Analysis of Sustainable Energy Systems in Ecovillages: A Review of Progress in BedZED and Masdar City  [PDF]
Dan Zhu, Michael Kung, Liang Zhou
Low Carbon Economy (LCE) , 2015, DOI: 10.4236/lce.2015.61001
Abstract: This paper explores sustainable energy systems in ecovillages based on the concept of the Zero Energy Building. The cases discussed in this paper include BedZED in the United Kingdom and Masdar City in the Middle East. These two communities contain features characterized by the sustainable principles of the ecovillage concept by using renewable energy and reclaimed materials to reach a low/zero energy system in buildings. The creation of more ecovillages and the growth of current ecovillages play an important role in positively solving environmental and social problems. The low energy buildings in the ecovillages also act as a model for communities wishing to implement sustainable development.
The Ornstein-Uhlenbeck-Type Model with a Hybrid Dividend Strategy
Dan Zhu,Chuancun Yin
Journal of Applied Mathematics , 2013, DOI: 10.1155/2013/467948
Abstract: We consider the Ornstein-Uhlenbeck-type model. We first introduce the model and then find the ordinary differential equations and boundary conditions satisfied by the dividend functions; closed-form solutions for the dividend value functions are given. We also study the distribution of the time value of ruin. Furthermore, the moments and moment-generating functions of total discounted dividends until ruin are discussed. 1. Introduction In recent years, the dividend problem has gained a lot of attention in the actuarial literature. Dividend strategies for insurance risk model were first proposed by de Finetti [1], who considered a discrete time random walk with step size and found that the optimal dividend strategy must be a barrier strategy. From then on, the problem of optimal dividend strategy has been studied in continuous time, for example, Asmussen and Taksar [2], Albrecher et al. [3], Gao and Yin [4], Gerber and Shiu [5, 6], Wan [7] and so on. The optimal dividend problem in a compound Poisson model was studied by Gerber and Shiu [8]. Optimal dividend in an Ornstein-Uhlenbeck-type model with credit and debit interest was considered in Cai et al. [9]. For a class of compound Poisson process perturbed by diffusion with a threshold dividend strategy, the expected discounted penalty function has been studied by Wan [7]. The perturbed Sparre Andersen model with a threshold dividend strategy was settled by Gao and Yin [10]. Recently, the multilayer dividend strategy as an extension of the threshold dividend strategy has drawn many authors attention. For example, the perturbed Sparre Andersen and compound Poisson risk models with multilayer dividend strategy have been studied by Yang and Zhang [11, 12]. The integrodifferential equations for the expected discounted penalty function were derived and solved; when the claims are subexponentially distributed, the asymptotic formula for ruin probability is obtained. The Ornstein-Uhlenbeck-type model is a very important model in applied probability which has recently gained a lot of attention. See, for example, Cai et al. [9] and Fang and Wu [13]. More general, Wong and Zhao [14] consider the optimal dividends and bankruptcy in an Ornstein-Uhlenbeck process with the surplus-dependent credit/debit interest rate. Motivated by the above work, in this paper, we consider a hybrid dividend strategy which combined a barrier strategy with a threshold strategy in an Ornstein-Uhlenbeck-type model. For simplicity, we consider only one threshold and one barrier. The remainder of the paper is organized as follows. In
On the growth rate of a linear stochastic recursion with Markovian dependence
Dan Pirjol,Lingjiong Zhu
Mathematics , 2015, DOI: 10.1007/s10955-015-1280-3
Abstract: We consider the linear stochastic recursion $x_{i+1} = a_{i}x_{i}+b_{i}$ where the multipliers $a_i$ are random and have Markovian dependence given by the exponential of a standard Brownian motion and $b_{i}$ are i.i.d. positive random noise independent of $a_{i}$. Using large deviations theory we study the growth rates (Lyapunov exponents) of the positive integer moments $\lambda_q = \lim_{n\to \infty} \frac{1}{n} \log\mathbb{E}[(x_n)^q]$ with $q\in \mathbb{Z}_+$. We show that the Lyapunov exponents $\lambda_q$ exist, under appropriate scaling of the model parameters, and have non-analytic behavior manifested as a phase transition. We study the properties of the phase transition and the critical exponents using both analytic and numerical methods.
Synergetic Analysis and Possible Control of Vortex-Induced Vibrations in a Fluid-Conveying Steel Catenary Riser Synergetic Analysis and Possible Control of Vortex-Induced Vibrations in a Fluid-Conveying Steel Catenary Riser
MENG Dan,ZHU Chongji
- , 2015,
Abstract: This work aimed to demonstrate possibilities for both active and passive control of the vortex-induced vibration and fatigue life of steel catenary risers via an analysis of the self-organization and evolution of the structural vibration based on synergetic theory. An analysis of the complex interrelated and synergistic relationship between the order parameter and the fast variable was performed, and the master equation of the nodal displacements was established as the order parameter for the evolution of the riser's structural vibration. Passive control methods include modifying the structure's elastic modulus, the internal fluid velocity, the top tension and the structural damping ratio, while an active control involves adjusting the external flow rate. Optimized parameters were obtained by analyzing the non-steady state solution of the master equation. The results show that the fatigue life greatly increases as the riser's elastic modulus decreases. In contrast, the fatigue life decreases with an increase of the internal fluid velocity. With an increase of the top tension, the vibration amplitudes and the number of modes may decrease, resulting in fewer bending stress cycles and a longer fatigue life. Furthermore, the structural damping ratio should be as large as possible. Finally, an active and passive control of the riser structure's response to vortex-induced vibration and its fatigue life can be achieved by carefully modifying the parameters mentioned above. The results may provide a theoretical framework for engineering practice concerning the design and control of steel catenary riser structures which are affected by vortex-induced vibration
A new improved filter for target tracking: compressed iterative particle filter  [PDF]
Hongbo Zhu, Hai Zhao, Dan Liu, Chunhe Song
Natural Science (NS) , 2011, DOI: 10.4236/ns.2011.34039
Abstract: Target tracking in video is a hot topic in computer vision field, which has wide applications in surveillance, robot navigation and human-machine interaction etc. Meanshift is widely used algorithm in video target tracking field. The basic mean shift algorithm only considers the color of targets as the tracking characteris- tic feature, so if the appearance of the target changes greatly or there exits other objects whose color is similar to the target, the tracking process will fail. To enhance the stability and robustness of the algorithm, we introduce par- ticle filter into the tracking process. Basic particle filter has some disadvantages such as low accuracy, high computational complexity. In this paper, an improved particle filter GA-UPF was proposed, in which a new re-sampling algorithm was used to predict target centroid position. The target tracking system of binocular stereo vision is designed and implemented. Experi- mental results have shown that our algorithm can tracking object in video with high accuracy and low computational complexity.
Traffic Pollution Influences Leaf Biochemistries of Broussonetia papyrifera  [PDF]
Yuanwen Kuang, Dan Xi, Jiong Li, Xiaomin Zhu, Lingling Zhang
Open Journal of Forestry (OJF) , 2012, DOI: 10.4236/ojf.2012.22010
Abstract: Paper mulberry (Broussonetia papyrifera) is one of multifunctional species in agroforestry systems as well as one of traditional forages in many countries of Asia. Fully expanded tender leaves of B. papyrifera wildly growing under two traffic densities (a high traffic loads bearing more than 1000 vehicles per hour, HT; and a relatively clear section with almost no traffic loads, NT) were collected for carbohydrates, amino acids and phytohormones analysis. Leaves exposed to traffic pollutants were revealed to have significant lower amounts of carbohydrates and total amino acids than those growing at relatively clear environment. The levels of abscisic acid in the leaves significantly increased, while gib-berellin acid, indoleaetic acid, and zeatin riboside in the leaves significantly decreased, with the traffic densities. The results indicated that the contents of carbohydrates, amino acids and phytohormones in the leaves of B. papyrifera could be adversely affected by traffic pollution. Variations of the leaf biochemistries of B. papyrifera exposed to traffic pollutants implied that B. papyrifera could physiologically regulate itself to adapt or resist traffic stress.
A Fuzzy Logic Behavior Architecture Controller for a Mobile Robot Path Planning in Multi-obstacles Environment
KarimBenbouabdallah,Zhu Qi-dan
Research Journal of Applied Sciences, Engineering and Technology , 2013,
Abstract: The path planning and obstacle avoidance are the most important tasks for an autonomous mobile robot moving in an unknown environment. This paper presents a simple fuzzy logic controller which involves searching target and path planning with obstacle avoidance. In this contest, fuzzy logic controllers are constructed for target searching behavior and obstacle avoidance behavior based on the distance and angle between the robot and the target as inputs for the first behavior and the distance between the robot and the nearest obstacle for the second behavior; then a third fusion behavior is developed to combine the outputs of the two behaviors to compute the speed of the mobile robot in order to fulfill its task properly. Simulation results show that the proposed approach is efficient and can be applied to the mobile robots moving in unknown environments.
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