5,164 research outputs found
An Elliptic Curve-based Signcryption Scheme with Forward Secrecy
An elliptic curve-based signcryption scheme is introduced in this paper that
effectively combines the functionalities of digital signature and encryption,
and decreases the computational costs and communication overheads in comparison
with the traditional signature-then-encryption schemes. It simultaneously
provides the attributes of message confidentiality, authentication, integrity,
unforgeability, non-repudiation, public verifiability, and forward secrecy of
message confidentiality. Since it is based on elliptic curves and can use any
fast and secure symmetric algorithm for encrypting messages, it has great
advantages to be used for security establishments in store-and-forward
applications and when dealing with resource-constrained devices.Comment: 13 Pages, 5 Figures, 2 Table
Root zone salinity management using fractional skimming wells with pressurized irrigation: Inception report
Wells / Aquifers / Pumping / Groundwater irrigation / Water quality / Salinity control / Irrigation programs / Climate / Waterlogging / Drainage / Soils / Land use / Cropping systems / Farm income
Similarities Between Classical Timelike Geodesics in a Naked Reissner-Nordstrom Singularity Background and the Behaviour of Electrons in Quantum Theory
It is generally assumed that naked singularities must be physically excluded,
as they could otherwise introduce unpredictable influences in their future null
cones. Considering geodesics for a naked Reissner-Nordstrom singularity, it is
found that the singularity is effectively clothed by its repulsive nature.
Regarding electron as naked singularity, the size of the clothed singularity
(electron) turns out to be classical electro-magnetic radius of the electron,
to an observer falling freely from infinity, initially at rest. The size
shrinks for an observer falling freely from infinity, with a positive initial
velocity. For geodetic parameters corresponding to negative energy there are
trapped geodesics. The similarity of this picture with that arising in the
Quantum Theory is discussed.Comment: 8 pages, 6 figure
Comments on "Lie group analysis of natural convection heat and mass transfer in an inclined surface"
 
An oscillating hydromagnetic non-Newtonian flow in a rotating system
AbstractAn exact solution of an oscillatory boundary layer flow bounded by two horizontal flat plates, one of which is oscillating in its own plane and the other at rest, is developed. The fluid and the plates are in a state of solid body rotation with constant angular velocity about the z-axis normal to the plates. The fluid is assumed to be second grade, incompressible, and electrically conducting. A uniform transverse magnetic field is applied. During the mathematical analysis, it is found that the steady part of the solution is identical to that of viscous fluid. The structure of the boundary layers is also discussed. Several known results of interest are found to follow as particular cases of the solution of the problem considered
Optimum Design of a Five-phase Permanent Magnet Synchronous Motor for Underwater Vehicles by use of Particle Swarm Optimization
Permanent magnet synchronous motors are efficient motors which have widespread applications in electric industry due to their noticeable features. One of the interesting applications of such motors is in underwater vehicles. In these cases, reaching to minimum volume and high torque of the motor are the major concern. Design optimization can enhance their merits considerably, thus reduce volume and improve performance of motors. In this paper, a new method for optimum design of a five-phase surface-mounted permanent magnet synchronous motor is presented to achieve minimum loss and magnet volume with an increased torque. A multi-objective optimization is performed in search for optimum dimensions of the motor and its permanent magnets using particle swarm optimization. The design optimization results in a motor with great improvement regarding the original motor. Finally, finite element analysis is utilized to validate the accuracy of the design
Simulink based Analysis and Realization of Line Commutated Grid Tied Inverter for Renewable Energy Applications
Non-conventional energy resources are increasingly used to fulfill load demands. Before using such energy sources the very important thing is analysis at the basic level. This paper presents analysis and realization of line commutated grid tied inverter for renewable energy applications. The current-voltage and power-voltage characteristics of solar PV array changes as parameters like solar insolation and temperature changes. These characteristics are found and realized using MATLAB software. Line commutated inverters are discussed in this paper for grid interactive modes of operations
The Relativistic Generalization of the Gravitational Force for Arbitrary Spacetimes
It has been suggested that re-expressing relativity in terms of forces could
provide fresh insights. The formalism developed for this purpose only applied
to static, or conformally static, space-times. Here we extend it to arbitrary
space-times. It is hoped that this formalism may lead to a workable definition
of mass and energy in relativity.Comment: 16 page
Malicious entities are in vain : preserving privacy in publish and subscribe systems
Publish and subscribe (pub/sub) system is a decoupled communication paradigm that allows routing of publications. Through a set of dedicated third party servers, referred to as brokers, publications are disseminated without establishing any link between publishers and subscribers. However, the involvement of these brokers raises security and privacy issues as
they can harvest sensitive data about subscribers. Furthermore, a malicious broker may collude with malicious subscribers and/or publishers to infer subscribers’ interests. Our solution is such that subscribers’ interests are not revealed to curious brokers
and published data can only be accessed by the authorised
subscribers. Moreover, the proposed protocol is secure against the collusion attacks between malicious brokers, publishers, and subscribers
Collusion defender : preserving subscribers’ privacy in publish and subscribe systems
The Publish and Subscribe (pub/sub) system is an
established paradigm to disseminate the data from publishers
to subscribers in a loosely coupled manner using a network
of dedicated brokers. However, sensitive data could be exposed
to malicious entities if brokers get compromised or hacked; or
even worse, if brokers themselves are curious to learn about
the data. A viable mechanism to protect sensitive publications
and subscriptions is to encrypt the data before it is disseminated
through the brokers. State-of-the-art approaches allow brokers
to perform encrypted matching without revealing publications
and subscriptions. However, if malicious brokers collude with
malicious subscribers or publishers, they can learn the interests
of innocent subscribers, even when the interests are encrypted.
In this article, we present a pub/sub system that ensures
confidentiality of publications and subscriptions in the presence
of untrusted brokers. Furthermore, our solution resists collusion
attacks between untrusted brokers and malicious subscribers (or
publishers). Finally, we have implemented a prototype of our
solution to show its feasibility and efficiency.
Index Terms: Collusion Resistance, Secure Pub/sub, Subscribers’
Privacy, Publications’ Confidentialit
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