检索结果-南通市图书馆

On Hiding Secret Information in Medium Frequency DCT Components Using Least Significant Bits Steganography

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2019年第3期118卷 529-546页

作者： Sahib Khan M A Irfan Arslan Arif syed tahir hussain rizvi Asma Gul Muhammad Naeem Nasir Ahmad Department of Electronics and Telecommunications Politecnico di Torino10129 TorinoItaly Department of Computer Engineering University of LahorePakistan Department of Statistics Shaheed Benazir Bhutto Women University PeshawarPakistan Department of Computer Science University of PeshawarPakistan Department of Electronic and Electrical Engineering Loughborough UniversityUnited Kingdom

This work presents a new method of data hiding in digital images,in discrete cosine transform *** proposed method uses the least significant bits of the medium frequency components of the cover image for hiding the secret information,while the low and high frequency coefficients are kept *** unaltered low frequency DCT coefficients preserves the quality of the smooth region of the cover image,while no changes in the high DCT coefficient preserve the quality of the *** the medium frequency components have less contribution towards energy and image details,so the modification of these coefficients for data hiding results in high quality stego *** distortion due to the changes in the medium frequency coefficients is insignificant to be detected by the human visual *** proposed methods demonstrated a hiding capacity of 43:11%with the stego image quality of a peak signal to the noise ration of 36:3 dB,which is significantly higher than the threshold of 30 dB for a stego image *** proposed technique is immune to steganalysis and has proved to be highly secured against both spatial and DCT domain steganalysis techniques.

关键词： DCT steganography image processing information security data hiding steganalyisis

Interaction properties of solitons for a couple of nonlinear evolution equations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第1期30卷 185-190页

作者： syed tahir Raza rizvi Ishrat Bibi Muhammad Younis Ahmet Bekir Department of Mathematics COMSATS University IslamabadLahore CampusPakistan Punjab University College of Information Technology University of the PunjabLahorePakistan Neighbourhood of Akcaglan Imarli Street Number 28/426030EskisehirTurkey

We study one-and two-soliton solutions for the Cahn–Allen(CA) equation and the Brethorton equation. The CA equation has broad spectrum of applications especially in anti-phase boundary motion and it is used in phase-field *** the Brethorton equation is a model for dispersive wave systems, it is used to find the resonant nonlinear interaction among three linear modes. We use the Hirota bilinear method to obtain one-and two-soliton solutions to the CA equation and the Brethorton equation.

关键词： Hirota bilinear method soliton interaction evolution equations

Proper Conformal Killing Vectors in Kantowski-Sachs Metric

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2018年第4期69卷 393-398页

作者： tahir hussain Muhammad Farhan Department of Mathematics University of Peshawar Khyber Pakhtunkhwa Pakista

This paper deals with the existence of proper conformal Killing vectors(CKVs) in Kantowski-Sachs *** to some integrability conditions, the general form of vector filed generating CKVs and the conformal factor is presented. The integrability conditions are solved generally as well as in some particular cases to show that the nonconformally flat Kantowski-Sachs metric admits two proper CKVs, while it admits a 15-dimensional Lie algebra of CKVs in the case when it becomes conformally flat. The inheriting conformal Killing vectors(ICKVs), which map fluid lines conformally, are also investigated.

关键词： conformal killing vectors killing vectors Kantowski-Sachs metric

Edge-Computing with Graph Computation:A Novel Mechanism to Handle Network Intrusion and Address Spoofing in SDN

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2020年第12期65卷 1869-1890页

作者： Rashid Amin Mudassar hussain Mohammed Alhameed syed Mohsan Raza Fathe Jeribi Ali tahir University of Engineering and Technology TaxilaPakistan University of Wah Wah CanttPakistan Jazan University JazanSaudi Arabia Abasyn University Islamabad IslamabadPakistan

Software Defined Networking(SDN)being an emerging network control model is widely recognized as a control and management *** model provides efficient techniques to control and manage the enterprise *** emerging paradigm is edge computing in which data processing is performed at the edges of the network instead of a central *** data processing at the edge nodes reduces the latency and bandwidth *** SDN,the controller is a single point of *** security issues related to the traditional network can be solved by using SDN central management and *** Spoofing and Network Intrusion are the most common *** attacks severely degrade performance and *** propose an edge computing-based mechanism that automatically detects and mitigates those *** this mechanism,an edge system gets the network topology from the controller and the Address Resolution Protocol(ARP)traffic is directed to it for further *** such,the controller is saved from unnecessary processing related to addressing *** propose a graph computation based method to identify the location of an attacker or intruder by implementing a graph difference *** using the correct location information,the exact attacker or intruder is blocked,while the legitimate users get access to the network *** proposed mechanism is evaluated in a Mininet simulator and a POX *** results show that it improves system performance in terms of attack mitigation time,attack detection time,and bandwidth requirements.

关键词： Software Defined Networking(SDN) edge computing Address Resolution Protocol(ARP) ARP inspection security graph difference

Optimal Islanding for Restoration of Power Distribution Systems Using Prim’s MST Algorithm

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2022年第2期8卷 599-608页

作者： Kaka Sanaullah Mingchao Xia Mazhar hussain Sharafat hussain Ammar tahir the School of Electrical Engineering Beijing Jiaotong UniversityBeijing 10044China the School of Computer and Information Technology Beijing Jiaotong UniversityBeijing 10044China

Power systems can suffer outages,causing complete or partial disconnection of their power supply to load centers within the distribution *** Generation(DG)plays an essential role in power *** can be used as a back-up power source to enhance the resiliency and reliability of a power *** mode operations after outages in an active distributing network(ADN)is an effective way to maintain continuity of the power supply to significant *** is a quite complicated task for power system operators to find the power flow *** studies have primarily used pre-defined guidelines to find feasible power flow paths,and have focused on multiple islands for *** these studies,possible restoration pathfinding with DG was the fundamental weakness,and furthermore,the power of DG was limited to pre-defined boundaries in the form of ***,in this study,a new algorithm has been proposed,which uses the minimum spanning tree(MST)method to find the most feasible *** proposed algorithm starts at any random node(in this case,DG),and progresses by selecting the next node with the least cost(weight),thus considering all the nodes through which power will *** proposed model is formulated as a multiobjective program considering the priority of loads and minimum power *** effectiveness of the proposed model is tested on a modified IEEE69-bus distribution system with the penetration of multiple distributed generation sources at different *** were compared with the strategies found in literature,and the proposed method was found to be feasible and efficient.

关键词： Active distribution network distributed generation islanding multi-objective minimum spanning tree

Energy Conditions and Conservation Laws in LRS Bianchi Type Ⅰ Spacetimes via Noether Symmetries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2019年第3期71卷 298-306页

作者： Sumaira Saleem Akhtar tahir hussain Department of Mathematics University of Peshawar

In this paper, we have completely classified the locally rotationally symmetric(LRS) Bianchi Type Ⅰ spacetimes via Noether symmetries(NS). The usual Lagrangian corresponding to LRS Bianchi Type Ⅰ metric is used to find the set of determining equations. To achieve a complete classification, these determining equations are generally integrated to find the components of NS vector field and the metric coefficients. During this procedure, several cases arise which give different Noether algebras of dimension 5,..., 9, 11, and 17. A comparison is established between the obtained NS and the Killing and homothetic vectors. Corresponding to all NS generators, the conservation laws are stated by using Noether's theorem. The metrics which we have obtained as a result of our classification are shown to be anisotropic or perfect fluids which satisfy certain energy conditions.

关键词： Bianchi type Ⅰ model Noether symmetry conservation Laws energy conditions

MECHANICALLY AND THERMALLY STABLE BLENDS OF POLY(STYRENE-BUTADIENE-STYRENE) WITH CONDUCTING POLY(THIOUREA-AZO-NAPHTHYL)

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2013年第12期31卷 1623-1631页

作者： Ayesha Kausar syed Tajammul hussain Nanosciences and Catalysis Division National Centre for PhysicsQuaid-i-Azam University Campus

A new aromatic azo-polymer, poly（thiourea-azo-naphthyl）（PTAN）, has been synthesized using 1-（5- thiocarbamoylaminonaphthyl）thiourea and diazonium salt solution of 2,6-diaminopyridine. PTAN was easily processable using polar solvents and had high molar mass 57 × 10^3 g/mol. Electrically conducting, mechanically and thermally stable rubbery blends of poly（styrene-butadiene-styrene）（SBS） triblock copolymer and PTAN were produced by solution blending technique. FESEM of SBS/PTAN blends revealed nano-scale dispersion of the conducting filler showing good adhesion between the matrix and PTAN. Remarkable effects of azo-content on the conductivity of SBS-based blends have been observed. Accordingly, PTAN loading from 10 to 60 wt% increased the conductivity from 1.24 to 1.66 S/cm. Relationship between PTAN loading and thermal stability of the materials was also investigated. With increasing the PTAN content, 10% gravimetric loss was increased from 484 to 500 ℃, while glass transition was enhanced from 119 to 126 ℃. Thermal and conducting data of the blend showed better results relative to pure elastomer but were lower than those of the conducting filler. Similarly, the tensile strength （57.35-62.33 MPa） of SBS/PTAN was improved relative to there of SBS. Fine balance of properties renders new materials fairly better than the existing elastomeric blends used in a number of applications.

关键词： Poly(thiourea-azo-naphthyl) SBS Electrical conduction Thermal stability Tensile strength.

Eliminating the Unruh effect of relativistic Dirac fields by partial measurements

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2020年第12期72卷 130-136页

作者： N A Khan syed tahir Amin Munsif Jan Centro de Física das Universidades do Minho e Porto Departamento de Física e AstronomiaFaculdade de CiênciasUniversidade do Porto4169-007 PortoPortugal Departamento de Física Instituto Superior TécnicoUniversidade de LisboaAv.Rovisco Pais1049-001 LisboaPortugal CeFEMA Instituto Superior TécnicoUniversidade de LisboaAv.Rovisco Pais1049-001 LisboaPortugal Instituto de Telecomunicacoes LAv.Rovisco Pais1049-001 LisboaPortugal CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China

The retrieval of lost entanglement for relatively accelerated fermionic observers of a tripartite system by a partial measurement technique has been *** the prospective of the negativities of one-tangles and theπ-tangle,we show that the degraded entanglement in noninertial frames with single-mode approximation is completely retrieved by an optimal strength of the partial measurement or the partial measurement *** addition,we find that the optimal one-tangle with respect to inertial and noninertial observers turns out to be the same for an optimal strength of partial measurements at q0=0 when two accelerated observers move with infinite acceleration.

关键词： entanglement retrieval π-tangle Unruh decoherence

NUMERICAL SIMULATION OF AN OSCILLATING FLOW PAST A CIRCULAR CYLINDER IN THE VICINITY OF A PLANE WALL

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2008年第5期20卷 547-552页

作者： SHAH syed Bilal hussain Department of Modern Mechanics University of Science and Technology of China

Oscillating flow around a circular cylinder in the vicinity of a plane wall was investigated by solving the two-dimensional incompressible Navier-Stokes equations with a finite element Galarkin residual method. The effect of the gap G/D between the cylinder surface and the wall on the flow behavior was studied. For the case of G/D 〈 0.25, the periodicity in the flow is attributed to both the outer shear layer instability and the oscillating frequency. As G/D 〉 0.25, vortex shedding occurs and the periodicity in the flow is mainly due to the competition of the oscillating frcqucncy and the vortex shedding frequency from an isolated stationary cylinder.

关键词： finite element method vortex shedding oscillating flow circular cylinder