Real traffic information was analyzed in the statistical characteristics and approximated as a Gaussian time series. A data source model, called two states constant bit rate (TSCBR), was proposed in dynamic traffic mo...Real traffic information was analyzed in the statistical characteristics and approximated as a Gaussian time series. A data source model, called two states constant bit rate (TSCBR), was proposed in dynamic traffic monitoring sensor networks. Analysis of autocorrelation of the models shows that the proposed TSCBR model matches with the statistical characteristics of real data source closely. To further verify the validity of the TSCBR data source model, the performance metrics of power consumption and network lifetime was studied in the evaluation of sensor media access control (SMAC) algorithm. The simulation results show that compared with traditional data source models, TSCBR model can significantly improve accuracy of the algorithm evaluation.展开更多
This paper examines spatio-temporal characteristics of an oasis economy and its relationship with water and mineral resources in the Tarim River Basin from 1965 to 2005. A spatial autocorrelation model, the center of ...This paper examines spatio-temporal characteristics of an oasis economy and its relationship with water and mineral resources in the Tarim River Basin from 1965 to 2005. A spatial autocorrelation model, the center of gravity model, and index system of the regional central city are used to probe the evolution laws of spatial structure of oasis economy. The study finds that: 1) The economic centre of gravity, whose variation track during this period follows linear rate law, was moving from headstream to middle reaches of the Tarim River. 2) Positive spatial autocorrelation which showed a waving and ascending trend of regional economy was significant and the neighbor effect of regional economic growth was strengthened continuously. 3) The regional economic centre was located in Hotan City before 1980, moved to Aksu City during the 1980s and to Korla City after 1990. We conclude that above all, during the recent four decades the evolution of the oasis economy in this region has gone through three stages: a traditional agriculture stage (before 1980), oasis agriculture and agricultural product processing stage (1980–1990) and oasis energy industry stage (after 1990). Furthermore, the dependence degree of the oasis economy on natural resources in different stages are studied by using dominance index, regression model, and grey relation method, which shows that an oasis econ- omy highly depends on water resources in the oasis agriculture and agricultural product processing stage while it de- pends more on mineral resources such as oil and natural gas during the oasis energy industry stage.展开更多
Air conditioning (AC) system is the one with asynchronous and uncertain nature. In this paper, the fuzzy discrete event system (FDES) is introduced to the research of AC energy-saving control. A fuzzy automaton modeli...Air conditioning (AC) system is the one with asynchronous and uncertain nature. In this paper, the fuzzy discrete event system (FDES) is introduced to the research of AC energy-saving control. A fuzzy automaton modeling is given for AC energy-saving control and effectiveness optimization is made. To facilitate the implement of the control and energy saving, priorities have been assigned to the major control steps based on logical reasoning. Forward-looking tree modeling based on FDES has been simplified to help further optimization, and a simple and concrete example has been put forward illustrating energy-saving control in AC system.展开更多
The paper focuses on the optimal control of natural resources in mining industry. The purpose is to pro- pose an optimal extraction series of these resources during the lifetime of the Mine's maintenance. Fol- lowing...The paper focuses on the optimal control of natural resources in mining industry. The purpose is to pro- pose an optimal extraction series of these resources during the lifetime of the Mine's maintenance. Fol- lowing the proposed optimal control model, a sensitivity analysis has been performed that includes the interest rate impact on the optimal solution. This study shows that the increasing of the interest rate sti- mulates faster extraction of the resources. The discounting factor induces that the resource has to be extracted faster hut this effect is counterbalanced by the diminishing returns of the annual cash flow. At higher parameters of "alpha" close to one of the power function about 80% from the whole resource will be extracted during the first 4 years of object/mine maintenance. An existence of unique positive root with respect to return of investment has been proposed and proved by two ways: by the "method of chords" and by using specialized software.展开更多
The traditional models of evaluating human resources are mainly based upon the discounted value of future payment, but these models fail to take the employment risk into account, and often neglect the uncertainty and ...The traditional models of evaluating human resources are mainly based upon the discounted value of future payment, but these models fail to take the employment risk into account, and often neglect the uncertainty and underes- timate the human resource value. This paper first introduces the option theory, and then presents human resources as the real commodity for the call option. Second, concerning the choices for the uncertainty decision, the decisions of delay- ing the employment of the human resources, expanding or deducing the scale of human resources, giving up or chang- ing human resources, etc., are made to deal with the future uncertainties appropriately. This will cause the investment to be more beneficial or to reduce the loss. Finally, the expand option theory of real options is used to evaluate the value of reinvestment in human resources, and the expand option theory could be provided as a reference for management im- plementation and decision-making in human resources.展开更多
"BIM (building information modeling)" and "sustainability" are two frequently used words in construction and academia today. BIM is a design-oriented tool, which generates a virtual three-dimensional model of a ..."BIM (building information modeling)" and "sustainability" are two frequently used words in construction and academia today. BIM is a design-oriented tool, which generates a virtual three-dimensional model of a project. Sustainability refers to prudent use of earth's natural resources, and construction sustainability is the application of this principle to building activities. Societies in general and the construction industry in particular--one of the largest in terms of natural resources consumed and waste produced--place high hopes on BIM and the principles of sustainability to reduce consumption and waste and to increase industry productivity. BIM's capabilities and limitations, currently more focused on model creation and energy simulations, are not well understood as they relate to construction sustainability and its goals. No method yet exists to evaluate BIM's contribution comprehensively to construction sustainability goals. This study presents a construction sustainability goals contribution matrix for BIM. The matrix indicates that this contribution may be more limited than it is commonly thought.展开更多
The key word for the design process of the photovoltaic tracking systems is the energetic efficiency. Using the tracking system, the photovoltaic panel follows the sun and increases the collected energy, but the drivi...The key word for the design process of the photovoltaic tracking systems is the energetic efficiency. Using the tracking system, the photovoltaic panel follows the sun and increases the collected energy, but the driving motors consume a part of this energy. In these terms, the optimization of the tracking systems became an important challenge in the modem research and technology. In this paper, a strategy for the dynamic optimization of the photovoltaic tracking systems is presented. The main task in optimization is to maximize the energetic gain by increasing the incoming solar radiation and minimizing the energy consumption for tracking. This strategy is possible by developing the virtual prototype of the tracking system, which is a control loop composed by the multi-body mechanical model connected with the dynamic model of the actuators and with the controller model. In this way, it is possible to optimize the tracking mechanism, choose the appropriate actuators, and design the optimal controller.展开更多
A fully integrated 3GHz low-power and low-phase-noise voltage-controlled oscillator (VCO) with a self-biasing current source was implemented in a standard 0.18μm CMOS process. A trade-off between noise and power wa...A fully integrated 3GHz low-power and low-phase-noise voltage-controlled oscillator (VCO) with a self-biasing current source was implemented in a standard 0.18μm CMOS process. A trade-off between noise and power was realized through the optimization of the improved current source. The VCO can be tuned from 2.83 to 3.25GHz with a 13.8% tuning range. The measured phase noise at 1MHz offset is -111dBc/Hz at a frequency of 3.22GHz while the core circuit draws less than 2mA from a 1.8V supply voltage. These results make the circuit suitable for a 5GHz wireless local area network (WLAN) receiver and 3.4 to 3.6GHz world interoperability for microwave access (WiMAX) application.展开更多
A resource-based economy is an economic system driven by the exploitation of mineral resources and dominated by the energy, mineral and other resource sectors. In resource- rich areas, there is often an investment bia...A resource-based economy is an economic system driven by the exploitation of mineral resources and dominated by the energy, mineral and other resource sectors. In resource- rich areas, there is often an investment bias toward the resource sector because of the existence of a threshold for investment in human capital in the manufacturing sector. Once the resource sector is dominant, it has a particular atwaction effect on the economic factors; its expansion and spread have a viscosity effect on industry families;, and the sunk costs and path dependence that emerge as industrialization evolves have a lock-in effect on the role of resources. This may give rise to development path dependence and the trap of resource advantage, resulting in a self-strengthening mechanism in resource-based economies. The key to escaping this trap is to break down the resource sector's original self-perpetuating mechanism and path dependence, introduce learning and innovation, adjust mechanisms far the distribution of resource benefits and realize industry coordination and transformational economic development.展开更多
基金The National Natural Science Foundation ofChia(No60372076)The Important cienceand Technology Key Item of Shanghai Science and Technology Bureau ( No05dz15004)
文摘Real traffic information was analyzed in the statistical characteristics and approximated as a Gaussian time series. A data source model, called two states constant bit rate (TSCBR), was proposed in dynamic traffic monitoring sensor networks. Analysis of autocorrelation of the models shows that the proposed TSCBR model matches with the statistical characteristics of real data source closely. To further verify the validity of the TSCBR data source model, the performance metrics of power consumption and network lifetime was studied in the evaluation of sensor media access control (SMAC) algorithm. The simulation results show that compared with traditional data source models, TSCBR model can significantly improve accuracy of the algorithm evaluation.
基金Under the auspices of Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-XB2-03-03)Western Doctor Plan of Chinese Academy of Sciences
文摘This paper examines spatio-temporal characteristics of an oasis economy and its relationship with water and mineral resources in the Tarim River Basin from 1965 to 2005. A spatial autocorrelation model, the center of gravity model, and index system of the regional central city are used to probe the evolution laws of spatial structure of oasis economy. The study finds that: 1) The economic centre of gravity, whose variation track during this period follows linear rate law, was moving from headstream to middle reaches of the Tarim River. 2) Positive spatial autocorrelation which showed a waving and ascending trend of regional economy was significant and the neighbor effect of regional economic growth was strengthened continuously. 3) The regional economic centre was located in Hotan City before 1980, moved to Aksu City during the 1980s and to Korla City after 1990. We conclude that above all, during the recent four decades the evolution of the oasis economy in this region has gone through three stages: a traditional agriculture stage (before 1980), oasis agriculture and agricultural product processing stage (1980–1990) and oasis energy industry stage (after 1990). Furthermore, the dependence degree of the oasis economy on natural resources in different stages are studied by using dominance index, regression model, and grey relation method, which shows that an oasis econ- omy highly depends on water resources in the oasis agriculture and agricultural product processing stage while it de- pends more on mineral resources such as oil and natural gas during the oasis energy industry stage.
基金PhD Programs Foundation of Ministry of Education of China( No.20060255006)Cultivation Fund of the Key Scientific and Technical Innovation Project from Ministry of Education of China (No.706024)
文摘Air conditioning (AC) system is the one with asynchronous and uncertain nature. In this paper, the fuzzy discrete event system (FDES) is introduced to the research of AC energy-saving control. A fuzzy automaton modeling is given for AC energy-saving control and effectiveness optimization is made. To facilitate the implement of the control and energy saving, priorities have been assigned to the major control steps based on logical reasoning. Forward-looking tree modeling based on FDES has been simplified to help further optimization, and a simple and concrete example has been put forward illustrating energy-saving control in AC system.
文摘The paper focuses on the optimal control of natural resources in mining industry. The purpose is to pro- pose an optimal extraction series of these resources during the lifetime of the Mine's maintenance. Fol- lowing the proposed optimal control model, a sensitivity analysis has been performed that includes the interest rate impact on the optimal solution. This study shows that the increasing of the interest rate sti- mulates faster extraction of the resources. The discounting factor induces that the resource has to be extracted faster hut this effect is counterbalanced by the diminishing returns of the annual cash flow. At higher parameters of "alpha" close to one of the power function about 80% from the whole resource will be extracted during the first 4 years of object/mine maintenance. An existence of unique positive root with respect to return of investment has been proposed and proved by two ways: by the "method of chords" and by using specialized software.
基金Projects BJY043 supported by National Social Science Foundation of China and NJ04013 supported by Inner Mongolia Education Bureau Higher EducationResearch
文摘The traditional models of evaluating human resources are mainly based upon the discounted value of future payment, but these models fail to take the employment risk into account, and often neglect the uncertainty and underes- timate the human resource value. This paper first introduces the option theory, and then presents human resources as the real commodity for the call option. Second, concerning the choices for the uncertainty decision, the decisions of delay- ing the employment of the human resources, expanding or deducing the scale of human resources, giving up or chang- ing human resources, etc., are made to deal with the future uncertainties appropriately. This will cause the investment to be more beneficial or to reduce the loss. Finally, the expand option theory of real options is used to evaluate the value of reinvestment in human resources, and the expand option theory could be provided as a reference for management im- plementation and decision-making in human resources.
文摘"BIM (building information modeling)" and "sustainability" are two frequently used words in construction and academia today. BIM is a design-oriented tool, which generates a virtual three-dimensional model of a project. Sustainability refers to prudent use of earth's natural resources, and construction sustainability is the application of this principle to building activities. Societies in general and the construction industry in particular--one of the largest in terms of natural resources consumed and waste produced--place high hopes on BIM and the principles of sustainability to reduce consumption and waste and to increase industry productivity. BIM's capabilities and limitations, currently more focused on model creation and energy simulations, are not well understood as they relate to construction sustainability and its goals. No method yet exists to evaluate BIM's contribution comprehensively to construction sustainability goals. This study presents a construction sustainability goals contribution matrix for BIM. The matrix indicates that this contribution may be more limited than it is commonly thought.
文摘The key word for the design process of the photovoltaic tracking systems is the energetic efficiency. Using the tracking system, the photovoltaic panel follows the sun and increases the collected energy, but the driving motors consume a part of this energy. In these terms, the optimization of the tracking systems became an important challenge in the modem research and technology. In this paper, a strategy for the dynamic optimization of the photovoltaic tracking systems is presented. The main task in optimization is to maximize the energetic gain by increasing the incoming solar radiation and minimizing the energy consumption for tracking. This strategy is possible by developing the virtual prototype of the tracking system, which is a control loop composed by the multi-body mechanical model connected with the dynamic model of the actuators and with the controller model. In this way, it is possible to optimize the tracking mechanism, choose the appropriate actuators, and design the optimal controller.
基金the National Natural Science Foundation of China(No.60276021)the State Key Development Program for Basic Research of China(No.G2002CB311901)~~
文摘A fully integrated 3GHz low-power and low-phase-noise voltage-controlled oscillator (VCO) with a self-biasing current source was implemented in a standard 0.18μm CMOS process. A trade-off between noise and power was realized through the optimization of the improved current source. The VCO can be tuned from 2.83 to 3.25GHz with a 13.8% tuning range. The measured phase noise at 1MHz offset is -111dBc/Hz at a frequency of 3.22GHz while the core circuit draws less than 2mA from a 1.8V supply voltage. These results make the circuit suitable for a 5GHz wireless local area network (WLAN) receiver and 3.4 to 3.6GHz world interoperability for microwave access (WiMAX) application.
文摘A resource-based economy is an economic system driven by the exploitation of mineral resources and dominated by the energy, mineral and other resource sectors. In resource- rich areas, there is often an investment bias toward the resource sector because of the existence of a threshold for investment in human capital in the manufacturing sector. Once the resource sector is dominant, it has a particular atwaction effect on the economic factors; its expansion and spread have a viscosity effect on industry families;, and the sunk costs and path dependence that emerge as industrialization evolves have a lock-in effect on the role of resources. This may give rise to development path dependence and the trap of resource advantage, resulting in a self-strengthening mechanism in resource-based economies. The key to escaping this trap is to break down the resource sector's original self-perpetuating mechanism and path dependence, introduce learning and innovation, adjust mechanisms far the distribution of resource benefits and realize industry coordination and transformational economic development.