AASRI Procedia最新文献

Nowadays the increasing utilization of alternative energy sources demand three phase power converters capable of delivering high quality energy to the low voltage grid. Good dead time compensation hardware and software are essential to keep low order harmonics at acceptable levels even at light load conditions, at acceptable costs. Low current waveforms with multiple zero crossings within a switching period are still problematic with today's technology. Such operating conditions often happen in PWM inverters and in variable frequency drives at or below 10% load. This paper describes a new method which uses a model for calculating the voltage error caused by dead time for each phase leg. The method is completely software based, but requires fast current measurement. A model splits each half period of the triangular carrier to time segments where the slopes of the currents in all phases, and the output voltage of all semiconductor phase legs are constant. It determines the duration of each of the time segments, and integrates the volt-seconds for a half period of the triangular carrier. The model is capable of handling discontinuous conduction as well. The resulting error voltage can be used to calculate a new, compensated duty factor which can be applied to the PWM modulator. The described algorithm was tested via computer simulation. A comparison was made with other, previous methods using the same inverter model.

This paper aims to develop a new system that converts vehicle motion into electrical energy. It exploits aerodynamics and ground-wheel dynamics to generate power. When the vehicle moves, an aerodynamic phenomenon is created on surfaces and the suspensions vibrate. The main objective consists on the exploitation of these dynamics to produce power and charge the batteries. A vehicle equipped with anemometer and sensors is used in order to invent a new device.

First, we present a wind turbine design and use cases. Then, we develop a new system which can convert suspension movement into power. The whole system is called “DynaPower”.

In the process of social regulation, the Selection of resolution about conflict between the regulator and the regulated, directly affects the efficiency and social equity of the regulation. The costs and benefits of social regulation were quantified by the opportunity cost, to promote the execution of regulation and to avoid violations. It is still not perfect for the Chinese market, and has multiple objectives on the social regulation. At present, by improving the level of social regulation, it can change the weak position of consumers in negative level, and encourage the moral consciousness of producers to in positive level, promoting the better material and spiritual aspects of market together.

To solve a problem of individualization in learning based on Intelligent Automated Educational Systems (IAES) involves to devise special methods of decision-making. In this article we propose to implement a complete individualization in learning (assessment, individual learning path management, adaptation of the curriculum and test sampling, the synthesis of man-machine dialog) by means of afference process simulation. It is considered the problem of searching for a compromise of goals between the models of a student, a teacher and a tutor within the base of the current learning environment. To this effect it is proposed a four-stage IAES-based decision-making scheme and synthesis mechanism of Cognitive Maps of Knowledge Diagnostic (CMKD). The problems of CMKD synthesis and visualization is considered. In conclusion, the results of approbation the proposed technologies in learning are provided.

Different age group of Male Kazak sheep and Xinjiang fine wool sheep were used in the current study to investigate the developmental changes of GHSR mRNA expression. After measurement of body weight, hypothalamus and pituitary were sampled to extract total RNA for determining the abundance of GHSR mRNA by RT-PCR and real-time PCR. The results indicated that: (1) For both breeds, body weight among different ages was significantly different (P<0.05), and from day 30 to 90, the Kazak's was notable higher than the Xinjiang's (P<0.01); (2) Hypothalamus GHSR mRNAs expression level increased firstly and then declined with growing in both breeds. From day 60 to 90, the mRNAs expression level of the Kazak was extremely higher than that of the Xinjiang (P<0.01); (3) Pituitary GHSR mRNAs expression level increased with growing in both breeds, and was highly positively correlated with the cumulative growth curves. From day 2 to 90, the pituitary GHSR expression level of the Kazak was extremely higher than that of the Xinjiang (P<0.01). The results predicated that it may be pituitary GHSR but not hypothalamus GHSR through which ghrelin influenced sheep growing.

The development and professionalization of a video game requires tools for analyzing the practice of the players and teams, their tactics and strategies. These games are very popular and by nature numerical, they provide many tracks that we analyzed in terms of team play. We studied Defense of the Ancients (DotA), a Multiplayer Online Battle Arena (MOBA), where two teams battle in a game very similar to rugby or American football. Through topological measures – area of polygon described by the players, inertia, diameter, distance to the base – that are independent of the exact nature of the game, we show that the outcome of the match can be relevantly predicted. Mining e-sport's tracks is opening interest in further application of these tools for analyzing real time sport.

The analysis, design and implementation of a zero voltage switched multi output push-pull topology is presented in this paper. To double the secondary output a voltage doubler circuit is introduced in each secondary winding of the multi output transformer. The voltage doubler introduced also helps in obtaining ZVS in the passive switches at the secondary of the transformer. To further add on the advantage of increased power packing density UC3825 an analog controller is deployed in the hardware prototype to regulate the output voltage against supply and load disturbances

Now how to improve the developing efficiency and enhance the scalability of network management system has become a hot issue in the current research. In this paper, according to the actual demands, understanding the functional requirements and analyzing the process of network topology management, we propose the hierarchical network topology management system based on managed object and view mechanism. Using an object-based management method, it achieves the expansion of the three-layer model of network topology management; using the view mechanism, it reduces the dependence on the specific needs for the system and achieves a hierarchical network topology management system.

In this paper authors offer the new method for solving coherent tasks in distributed computing system, based on resources of personal computers. Parameters of such resources are dynamically varying and that makes it hard for their application in distributed computations. To achieve ability of effective usage of personal computers, proposed method uses multiagent approach: proactive agent controls every personal computer in distributed computing system, and process of task solving is dispatched decentralized by interactions of agents. To solve every incoming coherent task agents of the system unite into community and that makes it easier to dispatch and perform computations. The main benefit of proposed method is decreasing the price for creating and maintenance of distributed computing system.

Based on the grey system theory, the paper establishes an electricity demand forecasting model for Jiangsu province, and verifies it using the data from the year 1997 to 2012. The result shows that the accuracy of this forecast model is “superior”. This proved that GM (1, 1) model used for the electricity demand forecasting of Jiangsu province can fully meet the needs of the forecast of electricity. In the mean time, the electricity demand of Jiangsu from the year 2013 to 2015(which year is the end of China's twelfth five-year plan) was forecasted by applying the model and the result shows that the electricity consumption in Jiangsu province will increase rapidly in the next few years. Up to the year 2015, it will reach 0.7187 trillion kW·h, which requests the acceleration of the generation of power, so as to meet the needs of the economic development of Jiangsu province in the next few years.