The short-distance low-power technologies for wireless access communications, including Bluetooth, Ultra-Wideband (UWB) and Wireless Fidelity (Wi-Fi), focus on the physical layer and Medium Access Control (MAC) layer....The short-distance low-power technologies for wireless access communications, including Bluetooth, Ultra-Wideband (UWB) and Wireless Fidelity (Wi-Fi), focus on the physical layer and Medium Access Control (MAC) layer. Bluetooth is a wireless protocol for exchanging data over short distances. It is an alternative to RS232 data cables. UWB is a radio technology that can be used at very low energy levels for short range. It provides flexible high-bandwidth wireless access. Wi-Fi enables the wireless connection of fast-access devices and mobile devices in Wireless Local Access Network (WLAN) and it is suitable for long distances. The standardizations of the above technologies have been developed and published soon after the emergence of these technologies. Among all the standards, Bluetooth and Wi-Fi are the most important ones.展开更多
In this paper,we discuss some non-trivial relations for ordered exponentials on smooth Riemannian manifolds.As an example of application,we study the dependence of the four-dimensional quantum Yang–Mills effective ac...In this paper,we discuss some non-trivial relations for ordered exponentials on smooth Riemannian manifolds.As an example of application,we study the dependence of the four-dimensional quantum Yang–Mills effective action on the special gauge transformation with respect to the background field.Also,we formulate some open questions about a structure of divergences for a special type of regularization in the presence of the background field formalism.展开更多
This paper focuses on the bus evacuation problem with pedestrians’short-distance walking ability between bus stations during no-notice disasters in downtown areas.A mixed-integer linear programming model is proposed ...This paper focuses on the bus evacuation problem with pedestrians’short-distance walking ability between bus stations during no-notice disasters in downtown areas.A mixed-integer linear programming model is proposed to solve this problem.The objective function is to minimize the evacuation time and number of casualties.The model obtains the flow of evacuees and buses on each arc to the route of buses in the process of evacuation.Furthermore,a real-time bus evacuation demand estimation method is proposed based on smart card data.Finally,the example of Zhongguancun area in Beijing is used to verify the practicality and validity of the model.The results show that pedestrian short-distance walking can effectively reduce casualties and improve the utilization rate of buses.展开更多
文摘The short-distance low-power technologies for wireless access communications, including Bluetooth, Ultra-Wideband (UWB) and Wireless Fidelity (Wi-Fi), focus on the physical layer and Medium Access Control (MAC) layer. Bluetooth is a wireless protocol for exchanging data over short distances. It is an alternative to RS232 data cables. UWB is a radio technology that can be used at very low energy levels for short range. It provides flexible high-bandwidth wireless access. Wi-Fi enables the wireless connection of fast-access devices and mobile devices in Wireless Local Access Network (WLAN) and it is suitable for long distances. The standardizations of the above technologies have been developed and published soon after the emergence of these technologies. Among all the standards, Bluetooth and Wi-Fi are the most important ones.
基金supported by the Ministry of Science and Higher Education of the Russian Federation,agreement 07515-2022-289supported in parts by the Foundation for the Advancement of Theoretical Physics and Mathematics‘BASIS’,grant‘Young Russian Mathematics’。
文摘In this paper,we discuss some non-trivial relations for ordered exponentials on smooth Riemannian manifolds.As an example of application,we study the dependence of the four-dimensional quantum Yang–Mills effective action on the special gauge transformation with respect to the background field.Also,we formulate some open questions about a structure of divergences for a special type of regularization in the presence of the background field formalism.
基金supported by the National Key R&D Program of China(No.2017YFC0803300)the National Natural Science Founda-tion of China(Grants No.71621001,71771021,71931002)the Fundamental Research Funds for the Central Universities,China(No.2021PT206).
文摘This paper focuses on the bus evacuation problem with pedestrians’short-distance walking ability between bus stations during no-notice disasters in downtown areas.A mixed-integer linear programming model is proposed to solve this problem.The objective function is to minimize the evacuation time and number of casualties.The model obtains the flow of evacuees and buses on each arc to the route of buses in the process of evacuation.Furthermore,a real-time bus evacuation demand estimation method is proposed based on smart card data.Finally,the example of Zhongguancun area in Beijing is used to verify the practicality and validity of the model.The results show that pedestrian short-distance walking can effectively reduce casualties and improve the utilization rate of buses.
