Applied Mechanics and Materials Vols. 373-375

Abstract: In wireless sensor networks, NLOS propagation often enlarges the errors of position estimates when time-of-arrival (TOA) measurements are used. To mitigate the effects caused by NLOS propagation, herein, an EKF-based robust non-parametric approach is proposed. In this paper, we utilize the variable kernel method to obtain an approximate noise density function, which is inexpensively computational and then used to improve the mobile positioning accuracy. Note that the standard EKF often works well when NLOS error is adequately low. This property could also be used to improve the accuracy of mobile positioning. In the proposed algorithm, a hard decision is employed to choose the rational position estimate which may come from the non-parametric approach or the standard EKF. Numerical simulations show a significant improvement over the standard EKF.

Abstract: Wireless sensor is a miniature battery powered device with limited energy; It contains a large number of the wireless router sensors in wireless sensor networks. Once these batteries placed in these sensors and deployed to the environment, we would be very difficult to artificially replace the battery, run out means of wireless sensor networks "death", so the battery energy is very precious. The energy levels of the network, in other words, to extend the life of the wireless sensor networks, has become an important research focus and design challenges. Today, LEACH is the most representative and most influential representation algorithm in the Topology control method field. To improve LEACH algorithm, Our novel IR-LEACH uses a new cluster head percentage of 3.79%; redefine the concept of round; cluster head transmission of data using a multi-hop transmission; TTL data segment is added to the cluster-head data. Simulation results display that IR-LEACH implement the above discussed improvements effectively and efficiently and improves the network lifespan over LEACH.

Abstract: A physically based approach for simulating fluid movement is proposed. Realistic animation and real time simulation are two objectives. Traditional animation technique can obtain virtual movement, but it has difficulty for realistic movement. Compared with the traditional animation technique, physically based animation can represent realistic movement better. The incompressible Navier-Stokes equations are used in our model, and the operator splitting method including semi-Lagrangian scheme and fast Fourier transform is employed to split the model into external force term, advection term, diffusion term and projection term. Every step is stable , so the whole process is also stable. Thus, the big time step can be taken to ensure real time simulation. Compared with the traditional technique, this method can be taken for realistic animation and real time simulation of fluid movement in computer graphics applications.

Abstract: We presented an algorithm to recognize overlapped bubbles in two-phase flow. We extracted bubble images from gray image by Background subtraction, and then converted them to binaries. Final images were segmented to compare them with the templates of bubble pattern. Finally, we obtained the recognition accuracy to compare their similarities. The recognition rate is to 93% and it is efficient in the field of the machine vision.

Abstract: This paper introduce the working principle of accumulator charging valve. According to the static analysis of principle and structure of the valve, the model of accumulator charging valve was established by AMESim. which simulated the charging pressure and other charging characteristics. According to the result of the simulation, some technical advices for improving the performance of the full hydraulic system are provided. Thecomparison between simulation and experiment proved that the model of the valve was accurate and reliable. The performance of the charging valve meets the request of the full hydraulic braking system exactly.

Abstract: Aiming at the low efficiency problem of the traditional gas-oil separator, this paper put forward a centrifugal gas-oil separator. In order to identify out the interior fluid field character of centrifugal gas-oil separator, RANS equation, RNG k-ε model and discrete phase model was applied to simulate the interior fluid field character and separation efficiency of centrifugal gas-oil separator. The simulation results showed that the flow field in the disc clearance was mainly laminar flow, and the flow field at the import and export of the disc was turbulence. Meanwhile, the velocity and pressure of the interior fluid field were equably distributed, the velocity and pressure in the disc clearance fluctuate in a tight range along vertical direction, and decrease along horizontal direction, and the particles in the disc clearance were distributed uniformly. The separation efficiency was 96.6% and the results met the design requirements.

Abstract: Storm surges have a hazardous influence on coastal regions, threatening infrastructures, ecosystems and human lives. A statistical study of storm surge magnitude makes it possible to determine the severity, and therefore better forecast and prevent losses. However, the assessment and grading remain controversial in academia. A storm surge grading system was designed based on data in Chinas coastal provinces of Zhejing, Fujian, Guangdong over the period 2003-2010 in this paper. Related variables include social factors, such as affected farmland, direct economic losses; and natural factors, like wind speed, maximum rainfall. Cluster analysis, Entropy method and factor analysis are applied to determine the detail and specific grading. This grading gave a better insight into the disaster and better forecast and control.

Abstract: The elastohydrodynamic lubrication (EHL) study of water-based ferrofluid bearing with single sine-shaped peak, rectangular-shaped valley and V-shaped valley was carried out. The influence of the amplitude and the width on the pressure and film thickness was discussed. The results reveal that the pressure and film thickness change apparently with the change of micro-morphology; The amplitudes of the local pressure peak and the film thickness increase with the increase of amplitudes; The widths of the local pressure peak and the film thickness increase with the increase of width.

Abstract: Electromagnetic control valve (ECV) controls an automobile vehicle air conditioning compressor based on a pulse width modulation (PWM) input signal that supplied from an external controller. For maintaining a suitable range of temperatures inside the vehicle, suction and crankcase port pressure controls the swash (wobble) plate at certain angle. Suction and crankcase port pressure controlled in ECV can be analyzed by experimental test by considering different technical assumptions. This research paper highlights the flow of air from crankcase port with correspondence with amount of variable supply of current to obtain the experimental test data which is important to maintain the vehicle temperature inside the compartment for passengers comfort.

Abstract: This paper proposed a parameter identification method for simplified models of open drainage systems. SWMM is used to identify these parameters by taking the rainfall data as the input. Simulations show that the results of the proposed method have high accordance with those of SWMM. The drainage system of Duke University is taken as an example to demonstrate our approach.