Advanced Materials Research Vol. 811

Abstract: In neural networks modeling approach, a non-linear model is estimated based on machine learning methods. The study discusses, analytically and numerically demonstrates the quality and interpretability of the obtained prediction accuracy results from prediction models based on advanced statistical methods and models based on neural networks (intelligent methods). Both proposed approaches are applied to the financial time series of s of VUB bond prices. We found that it is possible to achieve significant risk reduction in managerial decision-making by applying intelligent forecasting models based on the latest information technologies. In a comparative study is shown, that both presented modeling approaches are able to model and predict high frequency data with reasonable accuracy, but the neural network approach is more effective.

Abstract: This paper presents a dual-core floating point FFT processor design based on CORDIC algorithm, enabling high-speed floating-point real-time FFT computation, and its time complexity is (N / 4) Log (N / 2). The design unifiesthe floating complex multiplication and the evaluationof twiddle factors into an iteration, which not only reduces the complexity of complex multiplication but also reduces the difficulty when the butterfly unit deals with floating-point in fast Fourier transform. The butterfly unit unaffected by the size of external memory can handle the Fourier transform with high sample number, both having wider handling range and high handling precision. It uses two logical cores and pipeline technology to improve overall system throughput, with simple hardware structure and system stability.At the end, it does the post-simulation on the Altera chip EP2C35F672C6, and its timing simulation can be run properly under the 50 MHz clock frequency.

Abstract: With wider deployments of smart meters, smart grids, and distributed generation, power quality monitoring has become increasingly important. It is well known that fast Fourier transform (FFT) is a powerful tools for power signal harmonic analysis, but leakage effect, picket fence effect, and aliasing effect make FFT suffer from specific restrictions. In this paper, we proposed a new method for power signal harmonic analysis. The major components of this method are a frequency and phasor estimating algorithm, a real time procedure and an adaptive monitoring. To verify this method, we provided the comparisons of this method with FFT.

Abstract: Cantilever with modified aptamers on the gold surface was employed to detect platelet-derived growth factor-BB (PDGF-BB) and cocaine. The deflection increased when PDGF-BB and cocaine were added into the flowing cell, respectively. The defection depended on the concentration of PDGF-BB and cocaine. It was also found the microcantiver went back to the same position as without cocaine after adding cocaine aptamer in situ, which proved that the cantilever could be reused. The deflection arose from the specific interaction between aptamer and its target.

Abstract: In this paper, a reflective type optical fiber sensor (OFS) based on multiple total internal reflections in heterodyne interferometry is proposed. The sensor is made of a multimode optical fiber which cladding was removed and polished as a top shape. And the end surface of the sensor is designed as a micro-mirror. As a heterodyne optical source is launched into the optical fiber sensor at a suitable incident angle, we can obtain the phase difference between s-and p-polarizations at the output of the optical fiber sensor. By numerical simulation, it is clear that the resolution of the system by using the intensity method can reach refractive index unit (RIU) at least in the measurement range of. The OFS could be valuable for chemical, biological and biochemical sensing. It has some merits, such as, high resolution and stability, small size and real-time measurement.

Abstract: To harvest ambient vibration energy of different directions, a micromachined vibration energy harvester which can harvest two-dimensional vibration energy was proposed. The harvester is composed of a curled piezoelectric cantilever, a proof mass and the substrate. One end of the cantilever is fixed onto the substrate and the other end is connected with a proof mass. It is the residual stress of micromachining processes that causes the cantilever to curl. A proof-of-concept prototype of the two-dimensional vibration energy harvester was assembled and tested to evaluate the performance. Experimental results show that the vibration direction with the highest energy scavenging efficiency changed with the frequency of the ambient vibration. The vibration energy of any direction in the neutral plane of the curled cantilever can be harvested by using the first two natural vibration modes of the prototype.

Abstract: Using traditional methods such as perturbation theory or Galerkin approach method to analyze the dynamic response of electrostatic devices is not easy due to the complexity of the interactions between the electrostatic coupling effect, the fringing field effect, the residual stress, the nonlinear electrostatic force and squeeze-film damping effect. Accordingly, the present study proposes a new approach for analyzing the dynamic response of such devices using a hybrid numerical scheme comprising the differential transformation method and the finite difference method by pure DC or combined DC / AC loading. The validity of the proposed scheme is confirmed by comparing the results obtained for the pull-in voltage of the micro-beam with those presented in the literature derived using a variety of schemes. Overall, the results show that the hybrid numerical scheme provides a suitable means of analyzing the nonlinear dynamic behavior of a wide variety of common electrostatically-actuated microstructures.

Abstract: Piezoelectric actuator is compared. The tension and compression symmetrical dual piezoelectric-stack actuator, studied in this paper, is presented finally. The structural principle of this actuator is introduced. The finite element model of this actuator is built up also. Dynamic performance of this actuator is simulated by the MATLAB Simulink, and the results of simulation are in agreement with that of the experiment.

Abstract: Time-cost optimization problem in service-workflows is a widely existing problem hard to be solved in practical systems. In this paper, an Niche Technique multi-objective PSO method is proposed. Generating initial optimal solutions with single-objective. External Population and Niche Technique and Meshing hybrid method is introduced to obtain an evenly distributed Pareto set. Experimental results prove that the proposed algorithm is efficient and effective. For various characteristic instances, more evenly distributed Pareto Sets are obtained with high quality.

Abstract: This article is to design and implement a perception interactive terminal software based on android platform. Its main function is appliance control, energy consumption analysis, timing tasks, electricity alert, device management and system settings. The software provides the perception interface and function to grid companies and consumers. It achieves the inquiry of electric bill, electricity price and electricity consumption, the intelligent appliance control and the electricity management of household. It also has some practical value for smart grid construction. This paper mainly describes the functional architecture and implementation of the perception interactive terminal software.