The explosion in demand for wireless services experienced over the past 20 years has put significant pressure on system designers to increase the capacity of the systems being deployed. While the spectral resource is very scarce and practically exhausted, the biggest possibilities are predicted to be in the areas of spectral reuse by unlicensed users or in exploiting the spatial dimension of the wireless channels. The former approach is now under intense development and is known as the cogni- tive radio approach (Haykin 2005).
標簽： Multi-Antenna Wireless Channels Modeling
上傳時間： 2020-06-01
上傳用戶：shancjb
The wide deployment of wireless networks and mobile technologies, along with the significant increase in the number of mobile device users, have created a very strong demand on various wireless-based, mobile-based software application systems and enabling technologies. This not only provides many new business opportunities and challenges to wireless and networking service providers, mobile technology ven- dors, and software industry and solution integrators, butalso changes and enhances people’s lives in many areas, including communications, information sharing and exchange, commerce, home environment, education, and entertainment. Business organizations and government agencies face new pressure fortechnology updatesto upgrade their networking infrastructures with wireless connectivity to enhance enterprise-oriented systems and solutions.
標簽： Wireless-Based Software Systems
上傳時間： 2020-06-01
上傳用戶：shancjb
The “bottom-line” metrics of cash flow, demand, price, and return on investment are driven by a second set of financial metrics represented by value to the customer, cost, and the pace of innovation. Get them right relative to competition and impressive bottom-line results should follow. Because of their importance, we call value to the customer, variable cost, and the pace of innovation the “fundamental metrics.”
標簽： Planning Product Systems Driven Value and
上傳時間： 2020-06-06
上傳用戶：shancjb
n its Framework and Roadmap for Smart Grid Interoperability Standards, the US National Institute of Standards and Technology declares that a twenty-first-century clean energy economy demands a twenty-first-century electric grid. 1 The start of the twenty-first century marked the acceleration of the Smart Grid evolution. The goals of this evolution are broad, including the promotion of widespread and distributed deployment of renewable energy sources, increased energy efficiency, peak power reduction, automated demand response, improved reliability, lower energy delivery costs, and consumer participation in energy management.
上傳時間： 2020-06-07
上傳用戶：shancjb
Electric distribution networks are critical parts of power delivery systems. In recent years, many new technologies and distributed energy resources have been inte- grated into these networks. To provide electricity at the possible lowest cost and at required quality, long-term planning is essential for these networks. In distribution planning, optimal location and size of necessary upgrades are determined to satisfy the demand and the technical requirements of the loads and to tackle uncertainties associated with load and distributed energy resources.
標簽： Distribution Electric Planning Network
上傳時間： 2020-06-07
上傳用戶：shancjb
A modern power grid needs to become smarter in order to provide an affordable, reliable, and sustainable supply of electricity. For these reasons, a smart grid is necessary to manage and control the increasingly complex future grid. Certain smart grid elements including renewable energy, storage, microgrid, consumer choice, and smart appliances like electric vehicles increase uncertainty in both supply and demand of electric power.
標簽： Intelligent Management Microgrid
上傳時間： 2020-06-07
上傳用戶：shancjb
Today, electric power transmission systems should face many demanding chal- lenges, which include balancing between reliability, economics, environmental, and other social objectives to optimize the grid assets and satisfy the growing electrical demand. Moreover, the operational environment of transmission systems is becoming increasingly rigorous due to continually evolving functions of interconnected power networks from operation jurisdiction to control responsibly – coupled with the rising demand and expectation for reliability.
標簽： Monitoring Protection Wide Area
上傳時間： 2020-06-07
上傳用戶：shancjb
With the continued growth in the world's population, there is a need to ensure availability of enough food to feed everyone. Advances in science and technology have helped not only to increase food production, but also to reduce food wastage. However, the latter has the potential to be improved to a significant extent through appropriate matching of supply and demand, and with proper handling during storage and transit. Given the amount of food wastage that occurs after a food item leaves the “farm” on its way to the “fork,” and the availability of means to reduce such wastage, there really is no excuse for feigned ignorance.
標簽： Automation Industry Network Sensor RFID Food and the in
上傳時間： 2020-06-08
上傳用戶：shancjb
學術論文 Thedemandintourismischaracterizedbyseveralnewtrendsinpresenttime.Tourism demand is strongly influenced by demographic, environmental, technological changes and changes in the values of society and lifestyle (Alejziak, 2007).
標簽： 旅行
上傳時間： 2021-11-12
上傳用戶：13787166689
隨著光伏發電系統快速發展,以及電動汽車充電樁的普及,傳統的剩余電流保護器無法滿足實際需求。介紹了一款B型剩余電流保護器,采用磁調制剩余電流互感器和零序電流互感器采集剩余電流。根據GB/T 22794—2017標準要求,可識別1 kHz及以下的正弦交流、帶和不帶直流分量的脈動直流、平滑直流等剩余電流信號。經信號調理電路將電壓信號送到單片機進行采集和判斷。通過試驗測試,該樣機在測試精度和速度上均符合國家標準的相關要求。The rapid development of photovoltaic power generation systems and the popularity of electric vehicle charging piles make the traditional residual current protective devices unable to meet the actual demand.This paper proposed a type B residual current protective device,which uses the magnetically modulated residual current transformer and the zero sequence current transformer to acquire the residual current.According to the requirements of GB/T 22794—2017,the type B residual current protective device can detect sinusoidal AC residual current of 1kHz and below 1kHz,pulsating DC residual current with and without DC component,smooth DC residual current and so on.The signal processing circuit sends the voltage signal to the MCU for acquisition and judgment.Through experimental tests,the device meets the relevant requirements of national standards in terms of test accuracy and speed.
標簽： 電流保護器
上傳時間： 2022-03-27
上傳用戶：
