By development outlook is meant one's basic view on social development. Its complexity is involved at 4 levels. At the object level, it comes from the fact that the society is an open complex giant system (OCGS). At the cognition level, it comes from the reductionism and non-system thinking. At the practice level, it comes from the real benefit setup, conservative and unperfect facts of economic-political structure, and the international facts. At the philosophy level, it comes from the unity of opposites.
The advantages offered by titanium materials to the automotive industry including reducing vehicle weight, improving fuel economics, protecting environment, lowering noise and optimizing performance, application areas and application tendency are described. Low cost production technologies of sponge titanium and titanium materials are introduced and evaluated.
Recently, many people pay attention to design and construct various kinds of systems for digital city by means of automatic control, information and network technology as well as artificial intelligence in domestic cities and areas.
In this article, from system science point view, that a digital city is an Open Complex Giant System (OCGS) by the author is proposed. And the “ metasynthesis from qualitative opinion to quantitative understanding” which is the methodology of OCGS could be applied for dealing with digital city.
The paper puts forward a new thought in engineering structural reinforcement—conception reinforcement. In this thonght, the basic question and basic principle of engineering structural reinforcement is defermined macroscopically, using human being's thinking and judgment. The paper describes the whole prestressing reinforcement technology, and expounds an engineering example.
The eui gene of rice and the diversity of tall recessive germplasm of rice were newly identified. Male sterile lines with elongated uppermost internode, and their corresponding hybrids (-hybrids) possessing eui gene were developed and released. The goals and the target of -hybrid rice research and development are： to cut short dosage of GA3 used in hybrid rice seed production by 50%～90% with increasing seed yield and improving seed quality; to increase hybrid rice yield with decreasing N-fertilizer applied to rice.
The EUI1， EUI2 were isolated, and the diversity showing nucleotide deletion of euil and eui2 were also identified This will provide the materials to enhance the studies on following area： plant growth and development, GA melabolism, growth hormones and heterosis, molecular mechanism of mutation, as well as gene engineering.
There exists uncertainty in most problems in man´s practices and the uncertainty hinders decisionmakers from defining accurately indices values when they evaluate the system. For this problem, present decision-makers often define an interval number to denote this index value, but none has studied the interval number decision model in grey target decision. In this paper, the interval number, the distance of m dimension interval number and its characteristics are defined firstly, and the fact that the distance of interval number generalizes the distance of real number is proved, then, the method to normalize the interval number is developed. Based on the above, the multi-attribute decision model of grey target based on interval number is derived, which extends the grey target decision model from real number sequence to interval number sequence and richens the grey theories in grey target decision. Last, the validity and practicability are illustrated with an example.
The Ohm´s Law in solution considering the gas and liquid distribution in porous electrodes is given. Based on the mathematical model of the single pore electrode, the effective three-phase boundary length of the electrochemical reaction is defined and calculated. One-dimensional current and overpotential mathematical model of the porous electrode process is also established by the gas and liquid distribution theory of the porous medium. Current and overpotential distributions along normal direction of the electrode are given by numerical iteration method. Influence of the gas saturation and effective three-phase boundary length to the current and overpotential distributions are discussed.
It is an extended discussion on the stir kinetic energy conservation law, which is proposed by OuYang Shoucheng. The authors think that stir kinetic energy conservation law is an important principle and analysis method for stability and evolutionism of systems. It is not only an approach for explaining stability of system, but also the analysis method for evolutionism of system, and it points out some problems in Newton's theories as well.
While quadrilateral membership function is used as general membership function, Stone-Weierstrass theorem is utilized to prove that fuzzy systems with arbitrary membership functions are capable of approximating any continuous function on a compact set. It is a generalization for theory of basic fuzzy systems approximating any continuous non-linear function. The performance of fuzzy systems to approximate random non-linear function is the theoretical basis of fuzzy system's application in system identification.
Smoke is the important parameter of fire detection, and smoke particle size and its distribution may affect the sensitivity of smoke detectors directly. However, up to now there had no report about such research. In this paper, the theory, configuration and measurement method of Scanning Mobility Particle Sizer (SMPS) were described and the particle size and its distribution of four standard fire smoke were measured by SMPS. The particle size distribution function of smoke were studied by mathematic fitting methods, and the result of research showed that Logarithm Normal Distribution (LND) could represent the distribution of fire smoke particle size. The results may be benefit for the foundational research on fire smoke detection.
This paper firstly defines a group of system evaluation methods of attributes difference. Secondly, it puts forward one new combination evaluation method , in order to solve the problem of inconsistencies in the conclusions, which is caused by adopting many different single methods to evaluate the same objective. This method is used to evaluate the comprehensive competitive power of 15 cities in western China .to make the system evaluation more scientific and useful.
With regard to the characteristics of uncertain network-induced delay, an idea of using Generalized Predictive Control (GPC) is proposed in networked control systems. To overcome the influence of modeling mismatch and uncertainty of a system, an error predictive model is further built based on BP neural network, and error predictive value is used to compensate output predictive value, which forms a new control algorithm of GPC, and smooth filtering weighted controlled input variable is adopted. Random-delay-time characteristic of data transmission is tested in a networked control system. GPC and GPC with error compensation are compared in the system. GPC with BP error compensation is verified to have better performance in a modeling mismatch system.
The filtering property of empirical mode decomposition is analyzed in the paper. Aimed at the low signal/noise ratio and non stationary feature of vibration signal of cyclic machine, EMD is introduced to the noise reduction of vibration signal and the useful signal is given prominence efficiently, which offers the more efficient foundation to monitor on line and fault diagnosis of cyclic machine. By the simulation and application, it shows that EMD is very useful in reducing noise and provides new means of vibration signal analyzing.
This paper presents a GIS-based visual simulation methodology for concrete dam construction process, in which system simulation techniques are integrated with visualization techniques. GIS-based visual simulation system (GVSS) was developed by the authors. GVSS is a powerful schedule planning tool offering visualizing and querying capabilities simultaneously. GVSS has been applied to a real concrete dam construction project, which verified the feasibility of the methodology and GVSS.
As the expanding of power system capacity, the technologies of short circuit current limiting in power systems have been concerned greatly. This paper introduces a novel bridge type solid state current limiter and a new control strategy is proposed. The characters and operating principle of a novel bridge solid-state current limiter has been developed in detail. Simulation based on Matlab/Simulink is analysed and a laboratory set-up in which the thyristor is controlled by a single chip computer is tested. The results show that the FCL mode is successful in both computer simulation and laboratory test in limiting the fault currents.
Subway fire disaster is more hazardous than overground fire. Daegu underground railway fire disaster in Korea leads to a disastrous result. By means of fire simulation, recurrence of fire process, fire phenomenon and its reason could be studied. Based on FDS, the distribution of temperature and smoke with or without forced ventilated and smoke controlled system in Daegu subway fire are compared, and the effect on subway fire disaster control is also discussed in this paper.
The main spindle system is a key part on the machine tools. The quality of thermal behavior influences the machining accuracy of machine tools directly. In this paper, thermal characteristics of spindle system on the XK717 CNC milling machine are analyzed by combining finite element method with cooling model between spindle system and water tank. Effect rule to thermal characteristics of the main spindle system are obtained. The cooling jacket on the main spindle is improved by the results. This research provides the theoretical fundamentals for optimization design of CNC milling machine.
This paper summarized the development of dynamic model improvement methods, and researched the refinement methods based on frequency and response functions, which had been developed in recent years. In order to make the full use of the frequency and response functions obtained in the vibration test, the paper introduced three dynamic model improvement methods with frequency and response functions such as residual method, design parameter method, method of perturbation and so on. The paper may supply useful reference to the development of the spacecraft model’s updating technology.
This Issue
Aug 2005, Volume 7 Issue 8