768 research outputs found
Exploring Predicate Based Access Control for Cloud Workflow Systems
Authentication and authorization are the two crucial functions of any modern security and access control mechanisms. Authorization for controlling access to resources is a dynamic characteristic of a workflow system which is based on true business dynamics and access policies. Allowing or denying a user to gain access to a resource is the cornerstone for successful implementation of security and controlling paradigms. Role based and attribute based access control are the existing mechanisms widely used. As per these schemes, any user with given role or attribute respectively is granted applicable privileges to access a resource. There is third approach known as predicate based access control which is less explored. We intend to throw light on this as it provides more fine-grained control over resources besides being able to complement with existing approaches. In this paper we proposed a predicate-based access control mechanism that caters to the needs of cloud-based workflow systems
A Note on One Sided and Two Sided PO-Ternary Ideals in PO-Ternary Semiring
In this paper the term, left(lateral, right and two sided) PO-ternary ideal, maximal left(lateral, right and two sided) PO-ternary ideal, left (lateral, right and two sided) PO-ternary ideal of T generated by a set A, principal left (lateral, right and two sided) PO-ternary ideal generated by an element a left (lateral, right and two sided) simple PO-ternary semiring are introduced. It is proved that (1) the non-empty intersection of any two left (lateral, right and two sided) PO-ternary ideals of a PO-ternary semiring T is a left (lateral, right and two sided) PO-ternary ideal of T. (2) non-empty intersection of any family of left (lateral, right and two sided) PO-ternary ideals of a POternary semiring T is a left(lateral, right and two sided) PO-ternary ideal of T. (3) the union of any left PO-ternary ideals of a PO-ternary semiring T is a left PO-ternary ideal of T. (4) the union of any family of left(lateral, right and two sided) PO-ternary ideals of a PO-ternary semiring T is a left(lateral, right and two sided) PO-ternary ideal of T. (5) The left (lateral, right and two sided) PO-ternary ideal of a PO-ternary semiring T generated by a non-empty subset A is the intersection of all left(lateral, right and two sided) PO-ternary ideals of T containing A. (6) If T is a PO-ternary semiring and a∈T then L(a) = (Te Tea + na] = (Te Tea U na] (M(a) = (Tea Te + TeTe aTeTe + na] = ( Tea Te U TeTe aTeTe U na], R (a) = (aTe Te + na ] = (aTe Te U na] and T(a) = (Te Tea + aTe Te + TeTe aTeTe +na] = (Te Tea UaTe Te UTeTe aTeTe Una]). (7) A PO-ternary semiring T is a left(lateral, right) simple PO-ternary semiring if and only if (TTa] = T ((TaT U TTaTT] = T, (aTT] = T) for all a∈T
BSRS: Best Stable Route Selection Algorithm for Wireless Sensor Network Applications
Topological changes in sensor networks frequently render routing paths unusable. Such recurrent path failures have detrimental effects on the network ability to support QoS-driven services. Because of connectivity richness in sensor networks, there often exist multiple paths between a source and a destination. Since many applications require uninterrupted connectivity of a session, the ability to find long-living paths can be very useful. In this paper, we propose Best Stable Route Selection (BSRS) approach based on Artificial Bee Colony based search algorithm, ensures that contributes stable quality performance of network and to calculate the best stable path services randomly based on QoS parameter requirements and existing circulation load; so that efficient route selection can easily capture by designing of proposed BSRS approach. The implementation of the proposed BSRS technique is implemented using NS2 simulation environment and the AODV routing protocol is used to incorporate the proposed algorithm. The experimental results are measured in terms of end to end delay, throughput, packet delivery ratio, and energy consumption and routing overhead. The results show the proposed BSRS algorithm improves the flexibility of network node and performance of network when multiple inefficient paths exist
A STUDY ON STRUCTURE OF PO-TERNARY SEMIRINGS
This paper is divided into two sections. In section 1, the notion of a PO-ternary semiring was introduced and examples are given. Further the terms commutative PO-ternary semiring , quasi commutative PO-ternary semiring, normal PO-ternary semiring, left pseudo commutative PO-ternary semiring, lateral pseudo commutative PO-ternary semiring, right pseudo commutative PO-ternary semiring and pseudo commutative PO-ternary semiring are introduced and characterized them. Further the terms left singular, right singular and singular with respect to addition and left singular, right singular, lateral singular, singular with respect to ternary multiplication and two sided singular are introduced and made a study on them. In section 2, the terms; PO-ternary subsemiring, PO-ternary subsemiring of T generated by a set A, cyclic PO-ternary subsemiring and cyclic PO-ternary semiring are introduced. It is proved that T be a PO-ternary semiring and A be a non-empty subset of T. Then (A) = {a1a2....an-1;n ϵ N, a1,a2....an ϵ A } is a smallest PO-ternary subsemiring of T. Let T be a PO-ternary semiring and A be a non-empty subset of T. <A> = the intersection of all PO-ternary subsemirings of T containing A
Welding of nickel free high nitrogen stainless steel: Microstructure and mechanical properties
AbstractHigh nitrogen stainless steel (HNS) is a nickel free austenitic stainless steel that is used as a structural component in defence applications for manufacturing battle tanks as a replacement of the existing armour grade steel owing to its low cost, excellent mechanical properties and better corrosion resistance. Conventional fusion welding causes problems like nitrogen desorption, solidification cracking in weld zone, liquation cracking in heat affected zone, nitrogen induced porosity and poor mechanical properties. The above problems can be overcome by proper selection and procedure of joining process. In the present work, an attempt has been made to correlate the microstructural changes with mechanical properties of fusion and solid state welds of high nitrogen steel. Shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW), electron beam welding (EBW) and friction stir welding (FSW) processes were used in the present work. Optical microscopy, scanning electron microscopy and electron backscatter diffraction were used to characterize microstructural changes. Hardness, tensile and bend tests were performed to evaluate the mechanical properties of welds. The results of the present investigation established that fully austenitic dendritic structure was found in welds of SMAW. Reverted austenite pools in the martensite matrix in weld zone and unmixed zones near the fusion boundary were observed in GTA welds. Discontinuous ferrite network in austenite matrix was observed in electron beam welds. Fine recrystallized austenite grain structure was observed in the nugget zone of friction stir welds. Improved mechanical properties are obtained in friction stir welds when compared to fusion welds. This is attributed to the refined microstructure consisting of equiaxed and homogenous austenite grains
Ballistic behavior of boron carbide reinforced AA7075 aluminium alloy using friction stir processing – An experimental study and analytical approach
AbstractHigh strength-to-weight ratio of non-ferrous alloys, such as aluminium, magnesium and titanium alloys, are considered to be possible replacement of widely accepted steels in transportation and automobile sectors. Among these alloys, magnesium is self explosive and titanium is costlier, and aluminium is most likely to replace steels. Application of aluminium or its alloys is also thought of as an appropriate replacement in defence field, especially to enhance the easiness in mobility of combat vehicles while maintaining the same standard as that of conventional armour grade steels. Hence most of the investigations have been confined to aluminium or its alloys as base material and open an era of developing the newer composite materials to address the major limitation, i.e. tribological properties. The surface composites can be fabricated by incorporating the ceramic carbides like silicon carbide, carbides of transition metals and oxides of aluminium using surface modification techniques, such as high energy laser melt treatment, high energy electron beam irradiation and thermal spray process which are based on fusion route. These techniques yield the fusion related problems, such as interfacial reaction, pin holes, shrinkage cavities or voids and other casting related defects, and pave the way to need of an efficient technique which must be based on solid state. Recently developed friction stir processing technique was used in the present investigation for surface modification of AA7075 aluminum alloy, which is an alternative to steels. In the present investigation, 160 μm sized boron carbide powder was procured and was reduced to 60 μm and 30 μm using high energy ball mill. Subsequently these powders were used to fabricate the surface composites using friction stir processing.Ballistic performance testing as per the military standard (JIS.0108.01) was carried out. In the present work, an analytical method of predicting the ballistic behavior of surface composites was developed. This method was based on energy balance, i.e., the initial energy of impact is same as that of energy absorbed by multi layers. An attempt also has been made to validate the analytical results with the experimental findings. Variation between the analytical and experimental results may be accounted due to the assumptions considering such as isotropic behavior of target and shearing area of contact as cylindrical instead of conical interface As the analytical model yields the ballistic performance in the closer proximity of experimentally obtained, it can be considered to be an approximation to evaluate the ballistic performance of targets
An Improvised Methodology to Unbar Android Mobile Phone for Forensic Examination
At the end of 2015, there were 4.7 billion noteworthy mobile subscribers globally, equivalent to 63% of the world’s population. Mobile phones had all the essential components or characteristics neatly fitted into a small space and designed to achieve high speeds, massive storage, and increased functionalities. Smart phones used to carry out imparting or exchanging of information such as calling, texting, Internet browsing, e-mail, photos, videos, and etc. Criminals can use smart phones for a number of activities. Namely, committing a fraud over e-mail, harassment via text messages, drug trafficking, child pornography, etc. In this research paper, We demonstrate, if a mobile phone is identified in a criminal activity and if it is locked by any one of the locking mechanisms such as pattern lock, PIN lock and password lock, then how to unlock the mobile device without data loss for forensic examination. It is a great challenge for forensic experts to extract data from a mobile phone for forensic purpose that can be used as evidence in the court of law. The experimental results show that our approach can break all kinds of pattern locks
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