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Robust Image Watermarking Using LWT and Stochastic Gradient Firefly Algorithm

Computers, Materials & Continua 2023年第4期75卷 393-407页

作者： Sachin Sharma meena malik Chander Prabha Amal Al-Rasheed Mona Alduailij Sultan Almakdi Department of CSE Koneru Lakshmaiah Education FoundationGunturAndhra Pradesh522302India Deparmtent of CSE Chandigarh UniversityMohaliPunjab140413India Chitkara University Institute of Engineering and Technology Chitkara UniversityPunjab140401India College of Computer and Information Sciences Princess Nourah Bint Abdulrahman University84428Riyadh11671Saudi Arabia Department of Computer Science College of Computer Science and Information SystemsNajran UniversityNajran55461Saudi Arabia

Watermarking of digital images is required in diversified applicationsranging from medical imaging to commercial images used over the ***, the copyright information is embossed over the image in the form ofa logo at the corner or diagonal text in the background. However, this formof visible watermarking is not suitable for a large class of applications. In allsuch cases, a hidden watermark is embedded inside the original image as proofof ownership. A large number of techniques and algorithms are proposedby researchers for invisible watermarking. In this paper, we focus on issuesthat are critical for security aspects in the most common domains like digitalphotography copyrighting, online image stores, etc. The requirements of thisclass of application include robustness (resistance to attack), blindness (directextraction without original image), high embedding capacity, high Peak Signalto Noise Ratio (PSNR), and high Structural Similarity Matrix (SSIM). Mostof these requirements are conflicting, which means that an attempt to maximizeone requirement harms the other. In this paper, a blind type of imagewatermarking scheme is proposed using Lifting Wavelet Transform (LWT)as the baseline. Using this technique, custom binary watermarks in the formof a binary string can be embedded. Hu’s Invariant moments’ coefficientsare used as a key to extract the watermark. A Stochastic variant of theFirefly algorithm (FA) is used for the optimization of the technique. Undera prespecified size of embedding data, high PSNR and SSIM are obtainedusing the Stochastic Gradient variant of the Firefly technique. The simulationis done using Matrix Laboratory (MATLAB) tool and it is shown that theproposed technique outperforms the benchmark techniques of watermarkingconsidering PSNR and SSIM as quality metrics.

关键词： Image watermarking lifting wavelet transform discrete wavelet transform(DWT) firefly technique invariant moments

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One pot three component synthesis of spiro [indolo-3,10’-indeno[1,2-b]quinolin]-2,4,11’-triones as a new class of antifungal and antimicrobial agents

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Chinese Chemical Letters 2017年第1期28卷 136-142页

作者： Kalawati meena Sudesh Kumari Jitender M.Khurana Amita malik Chetan Sharma Harsh Panwar Department of Chemistry University of Delhi Delhi 110007 India Dyal Singh College University of Delhi Lodhi Road Delhi 110003 India Department of Dairy Microbiology College of Dairy Science and Technology Guru Angad Dev Veterinary and Animal Science UniversityLudhiana 141004 India

A simple and efficient three component procedure has been developed for the synthesis of highly substituted spiro[indolo-3,100-indeno[1,2-b]quinolin]-2,4,11＇-triones by one pot three component condensation of enaminones, isatin and indane-1,3-dione in ethanol：water（1：1） in presence of ceric ammonium nitrate（CAN） as catalyst. This method provides several advantages such as lesser reaction time, high yield of products and operational simplicity. The antimicrobial activity of some of the compounds has been investigated against six microbial strains, some of the tested compounds showed good antimicrobial activity.

关键词： Multicomponent reactions Isatin Spirooxindole Heterocycles Antimicrobial activity

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Active Queue Management Exploiting the Rate Information in TCP-IP Networks

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IEEE/CAA Journal of Automatica Sinica 2018年第1期5卷 223-231页

作者： Abderrahmane Boudi malik Loudini Laboratoire de la Communication dans les Systemes Informatiques Ecole nationale Superieure d'Informatique ESI Algiers 16309 Algeria IEEE

In this paper, we propose a new mechanism called explicit rate notification(ERN) to be used in end-to-end communications. The ERN scheme encodes in the header of transmission control protocol(TCP) packets information about the sending rate and the round trip time(RTT) of the flows. This new available information to the intermediate nodes(routers) is used to improve fairness, increase utilization, decrease the number of drops, and minimize queueing delays. Thus, it induces a better management of the queue. A comparison of our scheme with preexistent schemes, like the explicit congestion notification scheme, shows the effectiveness of the proposed mechanism.

关键词： Active queue management congestion control fairness transmission control protocol(TCP)

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Pulsed Corona Discharges and Their Applications in Toxic VOCs Abatement

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Chinese Journal of Chemical Engineering 1999年第4期7卷 351-362页

作者： Muhammad Arif malik Salman Akbar malik Applied Chemistry Division PINSTECHPO NiloreIslamabadPakistanDepartment of Biological SciencesQuaid-i-Azam UniversityIslamabadPakistan

Plasma processes are among the emerging technologies for volatile organic compounds (VOCs) abatement[1]. Both thermal plasmas and non-equilibrium plasmas (cold plasmas) are being developed for VOCs cleanup[2,3]. Particularly, pulsed corona discharges offer several advantages over conventional VOCs abatement techniques[4-7]. To optimize the existing technology and to develop it further, there is need to understand the mechanisms involved in plasma chemical reactions. Furthermore, it is strongly desirable to be able to predict the behavior of new VOCs in non-equilibrium plasma environment from the data known for a few representative compounds. Pulsed corona discharge technique is introduced here with citation of relevant literature. Fundamental principles, useful for predicting the VOCs' decomposition behavior, have been worked out from the published literature. Latest developments in the area, targeted to minimize the energy losses, improve the VOCs destruction efficiency and reduce the generation of unwanted organic and inorganic by-products, are presented.

关键词： corona discharges volatile organic compounds air purification water purification nonequilibrium plasma

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Modelling of electronegative collisional warm plasma for plasma-surface interaction process

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Plasma Science and Technology 2021年第4期23卷 48-54页

作者： Rajat DHAWAN Hitendra K malik Plasma Science and Technology Laboratory Department of PhysicsIndian Institute of Technology DelhiNew Delhi—110016India

An electronegative collisional plasma having warm and massive positive ions,non-extensive distributed electrons and Boltzmann distributed negative ions is modelled for the plasma-surface interaction process that is used for the surface *** the sheath formation is evaluated through the Bohm’s criterion,which is found to be modified,and the variation of the sheath thickness and profiles of the density of plasma species and the net space charge density in the sheath region in addition to the electric *** effect of ion temperature,nonextensivity and collisional parameter is examined in greater detail considering the collisional cross-section to obey power-law dependency on the positive ion *** positive ions are found to enter in the sheath region at lower velocities in the collisional plasma compared to the case of collision-less plasma;this velocity sees minuscule reduction with increasing *** increasing ion temperature and collisional parameter lead to the formation of sheath with smaller thickness.

关键词： electronegative sheath ion temperature non-extensivity sheath thickness power-law dependency collisions

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Critical Technical Awakenings

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Journal of Social Computing 2021年第4期2卷 365-384页

作者： Maya malik Momin M.malik the School of Social Work McGill UniversityMontréalH3A 0G4Canada the Institute in Critical Quantitative Computational&Mixed MethodologiesJohns Hopkins UniversityBaltimoreMD 21218USA

Starting with Philip ***’s 1997 essay on“critical technical practice”,we consider examples of writings from computer science where authors describe“waking up”from a previously narrow technical approach to the world,enabling them to recognize how their previous efforts towards social change had been *** use these examples first to talk about the underlying assumptions of a technology-centric approach to social problems,and second to theorize these awakenings in terms of Paulo Freire’s idea of critical ***,understanding these awakenings among technical practitioners as examples of this more general phenomenon gives guidance for how we might encourage and guide critical awakenings in order to get more technologists working effectively towards positive social change.

关键词： critical technical practice critical consciousness perspective transformation education machine learning

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Closed-Form Expression for the Exact Period of a Nonlinear Oscillator Typified by a Mass Attached to a Stretched Wire

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Advances in Applied Mathematics and Mechanics 2011年第6期3卷 689-701页

作者： malik Mamode Department of Physics Laboratoire PIMENTEquipe MASCUniversity of La Reunion97400 Saint-DenisFrance

The exact analytical expression of the period of a conservative nonlinear oscillator with a non-polynomial potential,is *** an oscillatory system corresponds to the transverse vibration of a particle attached to the center of a stretched elastic *** result is given in terms of elliptic functions and validates the approximate formulae derived from various approximation procedures as the harmonic balance method and the rational harmonic balance method usually implemented for solving such a nonlinear problem.

关键词： Nonlinear oscillator exact period elliptic integral

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Tapered coils system for space propulsion with enhanced thrust: a concept of plasma detachment

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Propulsion and Power Research 2022年第2期11卷 171-180页

作者： Lohit malik Department of Manufacturing Processes and Automation Engineering Netaji Subhas University of Technology(formerly Netaji Subhas Institute of Technology)New DelhiIndia Department of Mechanical and Aerospace Engineering Princeton UniversityPrincetonNew Jersey08540United States.

A concept for plasma detachment in a magnetic nozzle is developed based on the detachment region which is found to decrease with the taper angle of the coils employed in the proposed flexible three coil *** tapering the coils while resulting in the same crosssectional area,the plasma plume outside the throat grows radially that leads to an enhancement in the thrust from 2.67 mN to 5 mN at the final detachment plane for a rise in the taper angle from 0 to 13.The maximum thrust can reach about 9 mN when the middle coil is shifted closer to the right coil along with increasing middle-to-outer-coil diameter(inner)ratio from 1 to *** three-tapered-coils arrangement for a magnetic nozzle turns out to be a robust candidate for space propulsion offering the ability to control plasma detachment and tune thrust in-flight simply via mechanical movements without changing the current.

关键词： Tapered coil Magnetic field topology Magnetic nozzle Thrust Plasma detachment Space propulsion

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Novel concept of tailorable magnetic field and electron pressure distribution in a magnetic nozzle for effective space propulsion

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Propulsion and Power Research 2023年第1期12卷 59-68页

Magnetic nozzle appears to be a practical solution for prolonged space *** efficient handling of the spaceship,an in-flight solution to customize the thrust from the magnetic nozzle is *** a new concept of three-thick coils system is proposed for tailoring the magnetic field in-flight in accordance with electron pressure *** role of peak position of the pressure and its axial gradient is also uncovered for realizing higher *** three-fold increase in thrust is observed when the electron temperature is raised to w2.5 times of its original value at the exit *** set-up is optimized for its best performance and efficient use in the electric space propulsion sector with thrust approaching 5 *** particular,this can contribute to the attitude control or the precision pointing of the spacecraft,the technology for removal of space debris and manipulating the ion momentum flux lost to a wall or unsteady laser produced plasma flow in a magnetic nozzle.

关键词： Tailorable magnetic field Magnetic nozzle Electron pressure Thrust Effective space propulsion

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Frequency regulation by fuzzy and binary control in a hybrid islanded microgrid

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Journal of Modern Power Systems and Clean Energy 2015年第3期3卷 429-439页

作者： Pamela MANJARRES Om malik Department of Electrical and Computer Engineering University of CalgaryCalgaryABCanada

Islanded microgrids must be self-sufficient in terms of frequency and voltage control due to their islanded operation.A control strategy for frequency regulation by combining the operation of a wind generator,a diesel generator,a battery energy storage system and a dump load in a microgrid is proposed in this *** the proposed strategy,the control task is partitioned into two subtasks:1)choosing the appropriate element to be used for regulation,and 2)providing frequency regulation.A global controller chooses the element to ***,the frequency regulation is provided by separate individual *** proposed control strategy is tested on a microgrid with mixed types of generation and modeled on *** monitoring the power of individual elements and system frequency,it is shown that the proposed control strategy operates *** proposed strategy facilitates the integration of renewable energy sources and enhances frequency regulation.

关键词： Frequency regulation Fuzzy control Hybrid microgrid Automatic operation

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