Effect of temperature on geosynthetic rutting performance in asphalt pavement

In this research study, a 3D finite element model using ABAQUS software is used to evaluate the rutting performance of reinforced asphalt pavement. In this research study, the effects of three types of geosynthetic layers on the optimum location are studied at temperatures of 20°C, 40°C, and 50°C. According to the model analysis, the middle of asphalt layer is determined as the optimized location of geosynthetic layers in the pavement structure. The results showed that the effect of geosynthetic layers on rutting performance increased with increasing elastic modulus of geosynthetic at high temperature of pavement.     

Control of three phase PWM rectifier using virtual flux‐based predictive direct power control and SVM under harmonic conditions

In this paper, a new predictive direct power control algorithm to control the PWM rectifier based on virtual flux (VF) is presented. In this algorithm, supply network and the line inductances are assumed as an induction machine and so virtual flux space vectors are assumed corresponding with the space vector of the network voltages. Instantaneous active and reactive powers and finally convertor average voltage in both stationary and rotating reference frames are calculated by the virtual flux space vector components. The main advantages of the proposed method are low total harmonic distortion of the input current and low ripple in the instantaneous active and reactive powers and direct current‐bus voltage under harmonic distorted condition of the supply voltage in comparison with voltage‐based predictive direct power control (V‐PDPC) method. Proposed VF‐PDPC method with space vector modulation switching strategy was tested in simulations and compared with the V‐PDPC method. Copyright © 2015 John Wiley & Sons, Ltd.     

3D FEM analysis,dynamic modeling,and performance assessment of transverse flux PMSG for small‐scale gearless wind energy conversion systems

The transverse flux permanent magnet synchronous generator has a great potential for use in direct‐drive wind energy conversion systems due to its large pole numbers, high torque, and power density. This research work develops dynamic model of a single‐side transverse flux permanent magnet synchronous generator for use in a small‐scale gearless wind energy conversion system. For acquiring the parameters of the considered generator, required for dynamic modeling, 3D finite element model of the machine is developed and analyzed in both magneto‐static and transient modes. Field‐oriented control approach is employed for tracking maximum power point from the variable wind speed. The simulation results illustrate an accurate response of the system to the wind speed variation and proper performance of the developed dynamic model and control approach of the system. Copyright © 2015 John Wiley & Sons, Ltd.     

A channel differential EZW coding scheme for EEG data compression

In this paper, a method is proposed to compress multichannel electroencephalographic (EEG) signals in a scalable fashion. Correlation between EEG channels is exploited through clustering using a k-means method. Representative channels for each of the clusters are encoded individually while other channels are encoded differentially, i.e., with respect to their respective cluster representatives. The compression is performed using the embedded zero-tree wavelet encoding adapted to 1-D signals. Simulations show that the scalable features of the scheme lead to a flexible quality/rate tradeoff, without requiring detailed EEG signal modeling.     

Integrating IPsec within OpenFlow Architecture for Secure Group Communication

Network securityprotocolssuch as IPsechave been used for many years to ensure robust end-to-end communication and are impor-tant in the context of SDN.Despite the widespread installation of IPsec to date,per-packet protection offered by the protocol isnot very compatible with OpenFlow and flow-like behavior.OpenFlow architecture cannot aggregate IPsec-ESP flows in transportmode or tunnel mode because layer-3 information is encrypted and therefore unreadable.In this paper,we propose using the Secu-rity Parameter Index(SPI)of IPsec within the OpenFlow architecture to identify and direct IPsec flows.Thisenables IPsec to con-form to the packet-based behavior of OpenFlow architecture.In addition,by distinguishing between IPsec flows,the architectureis particularly suited to secure group communication.     

SpecSyn: an environment supporting the specify-explore-refineparadigm for hardware/software system design

System-level design issues are gaining increasing attention, as behavioral synthesis tools and methodologies mature. We present the SpecSyn system-level design environment, which supports the new specify-explore-refine (SER) design paradigm. This three-step approach to design includes precise specification of system functionality, rapid exploration of numerous system-level design options, and refinement of the specification into one reflecting the chosen option. A system-level design option consists of an allocation of system components, such as standard and custom processors, memories, and buses, and a partitioning of functionality among those components. After refinement, the functionality assigned to each component can then he synthesized to hardware or compiled to software. We describe the issues and approaches for each part of the SpecSyn environment. The new paradigm and environment are expected to lead to a more than ten times reduction in design time, and our experiments support this expectation     

System specification with the SpecCharts language

The SpecCharts language, which builds on VHDL to meet the unique requirements of system-level specification and design, is described. With an underlying model of behavioral hierarchy, SpecCharts modeling constructs enable designers to capture system specifications simply and precisely. SpecCharts constructs facilitate system-level design tasks by permitting high-level communication, maintaining information, and allowing design modification at an easy-to-comprehend level. The results of system-level design tasks are reflected in a modified SpecCharts, enabling the designer to evaluate the quality of each step. A detailed example demonstrates the use of SpecCharts     

Distance transform algorithm for measuring nanofiber diameter

This paper describes a new distance transform method used for measuring fiber diameter in electrospun nanofiber webs. In this algorithm, the effect of intersection is eliminated, which brings more accuracy to the measurement. The method is tested by a series of simulated images with known characteristics as well as some real webs obtained from electrospinning of PVA. Our method is compared with the distance transform method. The results obtained by our method were significantly better than the distance transform, indicating that the new method could successfully be used to measure electrospun fiber diameter.     

A mathemathical model for the calculation of the concentration at the outlet of an ozone generator

A mathematical model was generated to predict the composition of the outlet gas of ozone generators. In order to make the modelling possible it was important to predict the occurrence time and the exact location of each individual discharge zone. This was done by connecting a specially constructed ozone generator, which would locate the discharge zones, to a nanosecond pulse generator which would impose regular occurrence times for discharge columns. The experimental and theoretical outlet concentrations of this ozone generator were compared. The result was an excellent match which justified the assumptions made in the model. The mathematical model was also used to study the effect of different factors affecting the production of ozone.