Stalk and lie—The cost of Sybil attacks in opportunistic networks

2016 ◽  
Vol 73 ◽  
pp. 66-79 ◽  
Author(s):  
Sacha Trifunovic ◽  
Andreea Hossmann-Picu
Electronics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1085
Author(s):  
Jurairat Phuttharak ◽  
Seng W. Loke

Spatial crowdsourcing is a potentially powerful method for incorporating human wisdom into mobile computations to solve problems while exploiting the advantages of mobility and context-awareness. This paper proposes and investigates task assignments and recruitment in iterative spatial crowdsourcing processes to find regions of particular interest among a collection of regions. We consider cases where associations between regions can be exploited to reduce costs and increase efficiency in crowdsourcing. We describe five approaches, incorporated into crowdsourcing algorithms, for reducing the cost (the number of queries required) and increasing the efficiency (reducing the number of rounds of querying required) in using such spatial crowdsourcing. We demonstrate the performance improvements gained using these approaches based on simulation scenarios. The findings show the interplay and relationships among our proposed approaches using a range of metrics including responses, energy consumption, costs, and time usage. These metrics are demonstrated via a range of scenarios, showing that our proposed approaches can lead to improved performance over randomly choosing regions for inquiry.


Author(s):  
James F. Mancuso

IBM PC compatible computers are widely used in microscopy for applications ranging from control to image acquisition and analysis. The choice of IBM-PC based systems over competing computer platforms can be based on technical merit alone or on a number of factors relating to economics, availability of peripherals, management dictum, or simple personal preference.IBM-PC got a strong “head start” by first dominating clerical, document processing and financial applications. The use of these computers spilled into the laboratory where the DOS based IBM-PC replaced mini-computers. Compared to minicomputer, the PC provided a more for cost-effective platform for applications in numerical analysis, engineering and design, instrument control, image acquisition and image processing. In addition, the sitewide use of a common PC platform could reduce the cost of training and support services relative to cases where many different computer platforms were used. This could be especially true for the microscopists who must use computers in both the laboratory and the office.


Author(s):  
H. Rose

The imaging performance of the light optical lens systems has reached such a degree of perfection that nowadays numerical apertures of about 1 can be utilized. Compared to this state of development the objective lenses of electron microscopes are rather poor allowing at most usable apertures somewhat smaller than 10-2 . This severe shortcoming is due to the unavoidable axial chromatic and spherical aberration of rotationally symmetric electron lenses employed so far in all electron microscopes.The resolution of such electron microscopes can only be improved by increasing the accelerating voltage which shortens the electron wave length. Unfortunately, this procedure is rather ineffective because the achievable gain in resolution is only proportional to λ1/4 for a fixed magnetic field strength determined by the magnetic saturation of the pole pieces. Moreover, increasing the acceleration voltage results in deleterious knock-on processes and in extreme difficulties to stabilize the high voltage. Last not least the cost increase exponentially with voltage.


1994 ◽  
Vol 58 (11) ◽  
pp. 832-835 ◽  
Author(s):  
ES Solomon ◽  
TK Hasegawa ◽  
JD Shulman ◽  
PO Walker
Keyword(s):  

1998 ◽  
Vol 138 (2) ◽  
pp. 205-205
Author(s):  
Snellman ◽  
Maljanen ◽  
Aromaa ◽  
Reunanen ◽  
Jyrkinen‐Pakkasvirta ◽  
...  
Keyword(s):  

2004 ◽  
Vol 171 (4S) ◽  
pp. 40-40
Author(s):  
Leslee L. Subak ◽  
Stephen K. Van Den Eeden ◽  
Jeanette S. Brown ◽  
Arona I. Ragins ◽  
Eric Vittinghoff ◽  
...  

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