A Bluetooth low energy based beacon system for smart short range surveillance

Author(s):  
B G Anil Kumar ◽  
K C Bhagyalakshmi ◽  
K Lavanya ◽  
K H Gowranga
Author(s):  
Jordan Frith

The phrase the Internet of things was originally coined in a 1999 presentation about attaching radio frequency identification (RFID) tags to individual objects. These tags would make the objects machine-readable, uniquely identifiable, and, most importantly, wirelessly communicative with infrastructure. This chapter evaluates RFID as a piece of mobile communicative infrastructure, and it examines two emerging forms: near-field communication (NFC) and Bluetooth low-energy beacons. The chapter shows how NFC and Bluetooth low-energy beacons may soon move some types of RFID to smartphones, in this way evolving the use of RFID in payment and transportation and enabling new practices of post-purchasing behaviors.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tamar Goldzak ◽  
Alexandra R. McIsaac ◽  
Troy Van Voorhis

AbstractColloidal CdSe nanocrystals (NCs) have shown promise in applications ranging from LED displays to medical imaging. Their unique photophysics depend sensitively on the presence or absence of surface defects. Using simulations, we show that CdSe NCs are inherently defective; even for stoichiometric NCs with perfect ligand passivation and no vacancies or defects, we still observe that the low energy spectrum is dominated by dark, surface-associated excitations, which are more numerous in larger NCs. Surface structure analysis shows that the majority of these states involve holes that are localized on two-coordinate Se atoms. As chalcogenide atoms are not passivated by any Lewis base ligand, varying the ligand should not dramatically change the number of dark states, which we confirm by simulating three passivation schemes. Our results have significant implications for understanding CdSe NC photophysics, and suggest that photochemistry and short-range photoinduced charge transfer should be much more facile than previously anticipated.


2020 ◽  
Vol 1631 ◽  
pp. 012162
Author(s):  
Yan Long ◽  
Yongli Chen ◽  
Deyong Xiao ◽  
Zheng Li ◽  
Tianpeng Hou ◽  
...  

2021 ◽  
Vol 17 (2) ◽  
pp. 1-39
Author(s):  
Mai Ben Adar Bessos ◽  
Amir Herzberg

We investigate an understudied threat: networks of stealthy routers (S-Routers) , relaying messages to a hidden destination . The S-Routers relay communication along a path of multiple short-range, low-energy hops, to avoid remote localization by triangulation. Mobile devices called Interceptors can detect communication by an S-Router, but only when the Interceptor is next to the transmitting S-Router. We examine algorithms for a set of mobile Interceptors to find the destination of the communication relayed by the S-Routers. The algorithms are compared according to the number of communicating rounds before the destination is found, i.e., rounds in which data is transmitted from the source to the destination . We evaluate the algorithms analytically and using simulations, including against a parametric, optimized strategy for the S-Routers. Our main result is an Interceptors algorithm that bounds the expected number of communicating rounds by a term quasilinear in the number of S-Routers. For the case where S-Routers transmit at every round (“continuously”), we present an algorithm that improves this bound.


Sign in / Sign up

Export Citation Format

Share Document