Agricultural science and technology plays a key role in the construc tion of modern agriculture. The connotations and main characters of modern agric ulture in the 21st century were introduced in this paper. The author broug ht forward that the agricultural science and technology innovation was one of the stro ngest supporters to the agricultural development. It is necessary for the agricu ltural development and for the service of “San Nong” that the agricultural sci ence and technology system should be reformed.
The theory of five elements has had a profound influence on Chinese medicine. It manifests the holistic and comprehensive approach of traditional Chinese medici ne to treating diseases. However, it has its limitations in that it fails to tho roughly reflect the general relations between substances. To rectify this, Chine se medicine correlates five organs with five elements, which not only maintains the essence of the theory of five elements but in practice overcomes its limitat ions thanks to the introduction of Zangfu theory. Thus, Chinese medicine theor ies can be wound up to “the theory of five organs correlation”. To modernize t he Chinese medicine theories, we could categorize the mutual relations of five o rgans as those of generation, restriction and cooperation so as to explore the h olistic and comprehensive feature of Chinese medicine.
The precursors-the gestation process and the signal of impending earthquake of the Indian Ocean Earthquake of Ms 8-7 are recorded,with a serious of specially made monitoring instruments,including instruments for stress,resonance,tilt and earth potential.The recordings show that there are great differences for the stress in crust between before and after the eart hquake of Ms 8-7 and that of Ms 8-5. This fact indicates the essential distinction regarding to the formation of these two earthquakes.The causation of the tsunami is analyzed.The sign of underground material migration is also found in the gestation process of Ms 8-7 earthquake.
The principle, Discharge mode, alloying process and research works of double glow discharge plasma surface allloying process are introduced particularly in the paper. The advantage of the technology is analysised from theory. The technology is fit for high melting point metal surface alloying and surface alloying in surface of high melting point metal and some coloured metal.
An introduction will be made to the transportation env ironment characteristics of the upper-stream of Yangtze River (USYR), and the evolution and present status of the roll-on and roll off shipment (Ro-Ro shipment) in Yangtze River. Then five indicators are proposed to evaluate the contributions of Ro-Ro shipments in the upper-stream Yangtze River to regional social-economic developments. Calculating models for saving transport cost and en ergy will be built. Results based on the data in 2005 show that Ro-Ro shipment is a better alternative for truck transport in USYR, and it can make large contributions to both the environmental and social-economic development in the area. Both the governmen tand related enterprises should make more efforts to promote the development of the RRS of the USYR.
Gauss quadrature is used widely in many fields such as the engineering numerical computation, X-ray diffraction profile analysis, spectroscopy,and so on. The nodes and weight factors of Gauss-quadrature are essential data to the numerical integration. A method to compute the zeroes of the high-degree Legendre, Laguerre and Hermite polynomials, which are the nodes of Gauss-Legendre, Gauss-Laguerre and Gauss-Hermite Quadrature, respectively, is studied, and a very efficient algorithm scan-iteration method(SIM) is given. According to the properties of Legendre, Laguerre and Hermite polynomials, their definitions are modified a little, and the stable recursive relations to compute their value are obtained. To extract these polynomials, their root intervals are searched with a certain step within a certain range. After the intervals of all roots are obtained, the roots with the desired precision can be gotten by the general iteration methods such as secant or bisection method. Numerical experiments indicate that the method is very efficient and the high-precise roots of Legendre, Laguerre and Hermite polynomials can be extracted.
Aiming at the characteristic of airflow fluctuating in mine, based on the theory of mine ventilation, the theory of fluid mechanics, the theory of aerodynamics, the theory of mass and heat transfer, and the theory of infiltration flow through porous media, mathematical model about airflow fluctuating in mine is established；distribution features of flow field in goaf under the airflow fluctuating are researched by numerical simulation, and the model is reset and tested by corresponding experiment. The results show: mathematical model establi shed about airflow fluctuating in mine can be used for researching dist ribution of flow field in goaf,and can provide an effective method to fire preve ntion and treatment in goaf.
The problem that the liner allocation method can result in rank reversal is poin ted out. The concepts of sorting vectors and their relativity distribute ra tios are proposed to explain the causes of rank reversal. The improved liner al location method named sequence liner allocation method is analyzed to ensure ran k preservation. Finally the conclusion is validated with specific data.
According to the characteristics of IEEE 802.16-2005, a minimum reserve d traffic rate based fair scheduling algorithm in IEEE 802.16-2005 is proposed in this paper. It can support multiple service types and guarantee every service´s minimum reserved traffic rate. A compensation strategy is introduced to ensure m inimum reserved traffic rate of service which is in bad channel condition. At th e same time, services which have higher priority and are in good channel conditi on are granted more bandwidth to ensure the QoS (quality of service) and maximiz e the throughput performance. The simulation study shows that the algorithm can guar antee the minimum reserved traffic rate and distinguish the services in differen t levels. Furthermore, the algorithm has advantages in both fairness and through p ut performance compared with PF (proportional fair) algorithm. The algorithm pro posed in this paper is in accordance with IEEE 802-16-2005 and has gre at value.
More embedded system designers pay attention to how to reduce the po wer consumption of I/O devices. Traditional dynamic power management (DPM) polic ies only focus on the device requests, and neglect the application features behi nd the workload. Because of the assumption about the stationary workload, tradit ional DPM policies can not reach their expected goal under the multi-task envir o nment. The paper presents a stack-based predictive timeout strategy (SBPT). It c an predict the access pattern of the device I/O operations by analyzing the ca lling and stack information of tasks and combine predictions of multiple tasks to form the global prediction according to the multiple-service-requester mode l. At last, classify the I/O request by the global prediction and then make the de cision with the timeout technique based on the distribution of the grouped reque sts. An evaluation study of SBPT using the trace-driven simulation is performed. The results show that SBPT can adapt the non-stationary multi-task environment and reduces power consumption more efficiently than other policies.
The chief objective of wireless sensor networks designing is to pr ol ong the lifetime of networks, and topology control is the basic support for the objective. Aiming at the defect is that high redundancy of connectivity or low r obu st of structure in traditional methods, the problem was transformed into a model of multi-criteria minimum spanning tree ultimately, and a genetic algorithm wa s designed to deal with the model. A topology control method based on genetic alg orithm was proposed in this paper. The result of simulations suggests a topology with low total power consumption, high robust structure and low contention amon g nodes can be obtained by this method, and the lifetime of networks can be prol onged on the topology.
A high accurate steady-state physical model for high-voltage VDMOS is proposed in the paper. In the model, a more proper assumption result in obtaining both the electric field and the voltage in the double diffused channel region by analytical method; and after studying physical characteristic of VDMOS in detail, a differential equation concerning the electric field of the drift region is obtained, moreover, the analytical solution of this differential equation is given for the whole drift region, then the voltage drop of the drift region is obtained. The result shows that the calculation stability in the region adjacent to saturation of the drain current are improved in the paper´s model, and furthermore, the calculation prec ision of the paper´s model is high. Especially in the condition of high gate vol tage and high drain voltage it is improved to a great extent.
Battery lifetime is one of the critical design parameters for mobile computing d evices. Maximizing the battery lifetime is a particularly difficult problem due to the nonlinearity of the battery discharge behavior and its dependence on the discharge profile. In this paper, the problem of task scheduling with dynamic voltage scaling such that the maximum consume battery capacity is addressed. T o deal with the shortcoming of the existing battery-aware DVS policy, the idle time distribution adjustment procedure is proposed, which optimizes id le time dis tribution and then reduce the battery capacity consumption, and the cha nge of task scheduling under the procedure is analyzed. The experiment results s how that the proposed procedure can save more battery capacity consumption evidently than th e existing battery-aware DVS policy.
This paper presents a fast, low cost and non-contact gaze tracking system. The system is based on dual illuminators and a CCD camera. The camera captured the i mage of two eyes, and the synthesized information of both eyes was used to detec t the gaze direction. A fast pupil detection algorithm was proposed to speed up the image processing, and a simple model was used to recognize the gaze direction. Experimental results show that the system is applicable from -20° t o +20° angle of gaze in horizon and -16° to +16° angle of gaze in vertical. A human- computer interaction application proves that the system can estimate the user's gaze direction with tiny delay and relative high stability.
This Issue
Feb 2008, Volume 10 Issue 2