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Blockchain Mobile Wallet with Secure Offline Transactions

Computers, Materials & Continua 2023年第5期75卷 2905-2919页

作者： raed saeed rasheed Khalil Hamdi Ateyeh Al-Shqeerat Ahmed Salah Ghorab Fuad Salama AbuOwaimer Aiman Ahmed AbuSamra Faculty of Engineering Islamic University of GazaP.O.Box 108GazaPalestine Department of Computer Science College of ComputerQassim UniversityP.O.Box 52211BuraydahSaudi Arabia University College of Applied Sciences P.O.Box 1415GazaPalestine Palestine Technical College P.O.Box 6037Deir ElBalahPalestine

There has been an increase in the adoption of mobile payment systems worldwide in the past few ***,poor Internet connection in rural regions continues to be an obstacle to the widespread use of such *** top of that,there are significant problems with the currently available offline wallets;for instance,the payee cannot verify the number of coins received without access to the ***,it has been demonstrated that some existing systems are susceptible to false token generation,and some do not even permit the user to divide the offline token into smaller portions to be used as *** paper proposes a blockchainbased wallet system that provides a secure mobile payment service even if a user cannot access a reliable Internet *** approach relies on Bluetooth and digital signatures to establish and build a trust connection between the *** proposed solution overcomes the main limitations of existing systems that use offline transactions,such as the generation of fake offline tokens and the indivisibility of offline *** user buys Offline Tokens(OTs)from a server called an Offline Token Manager(OTM)to use them later to perform offline *** mobile device must store a single,signed offline token transaction to prevent fake *** the other hand,all offline transactions will be kept as a history in a particular local ***,when the receiver becomes online,it will send a convert request to the OTMto change the value of the OTs to the appropriate amount in real *** step requires a connection to the *** evaluate the effectiveness of the system,the Solidity programming language was used to develop a smart contract on the Ethereum blockchain with a backend application programming interface(API)and an android mobile *** proposed method has an advantage over other prominent wallets.

关键词： Mobile wallet blockchain smart contracts digital signature

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Recent progress in two-dimensional metallenes and their potential application as electrocatalyst

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Journal of Energy Chemistry 2024年第7期94卷 577-598页

作者： Umer Shahzad Mohsin saeed Muhammad Fazle Rabbee Hadi M.Marwani Jehan Y.Al-Humaidi Muhammad Altaf raed H.Althomali Kwang-Hyun Baek Md.Rabiul Awual Mohammed M.Rahman Department of Chemistry Faculty of ScienceKing Abdulaziz UniversityJeddah 21589Saudi Arabia Department of Biotechnology Yeungnam UniversityGyeongsanSouth Korea Center of Excellence for Advanced Materials Research(CEAMR) King Abdulaziz UniversityJeddah 21589Saudi Arabia Department of Chemistry College of SciencePrincess Nourah Bint Abdulrahman UniversityP.O.BOX 84428Riyadh 11671Saudi Arabia Department of Chemistry Center of Excellence for Innovation in Chemistry(PERCH-CIC)Center of Excellence in Materials Science and TechnologyFaculty of ScienceChiang Mai UniversityChiang Mai 50200Thailand Department of Chemistry College of Art and SciencePrince Sattam Bin Abdulaziz UniversityWadi Al-Dawasir 11991Saudi Arabia Western Australian School of Mines:Minerals Energy and Chemical EngineeringCurtin UniversityGPO Box U 1987PerthWA 6845Australia

In this article,we looked at metallenes,a novel class of two-dimensional(2D)metals that are attracting interest in the energy and catalysis *** is one area where their exceptional physicochemical and electrical characteristics might be *** are unique because they include several metal atoms that are not in a coordinated *** makes them more active and improves their atomic uti-lization,which in turn increases their catalytic *** article delves into the potential of two-dimensional metals as electrocatalysts for carbon dioxide reduction,fuel oxidation,oxygen evolution,and oxygen reduction reactions in the context of sustainable energy *** to the exception-ally high surface-to-volume ratio,large surface area as well as their optimized atomic use efficiency,2D materials defined by atomic layers are crucial for surface-related sustainable energy *** to its exceptional properties,such as high conductivity and the ability to enhance the exposure of active metal sites,2D metallenes have recently attracted a lot of interest for use in catalysis,electronics,and energy-related *** their highly mobility,adjustable surface states,and electrical struc-tures that can be fine-tuned,2D metallenes are promising nanostructure materials for use in energy con-version with the sustainable applications.

关键词： Metallenes Electrocatalysts Electrochemical processes Atomically thin structure

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A Double Threshold Energy Detection-Based Neural Network for Cognitive Radio Networks

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Computer Systems Science & Engineering 2023年第4期45卷 329-342页

作者： Nada M.Elfatih Elmustafa Sayed Ali Maha Abdelhaq raed Alsaqour Rashid A.saeed Department of Electrical and Electronics Engineering Red Sea UniversityPort Sudan33311Sudan Department of Information Technology College of Computer and Information SciencesPrincess Nourah bint Abdulrahman UniversityRiyadh11671Saudi Arabia Department of Information Technology College of Computing and InformaticsSaudi Electronic UniversityRiyadh93499Saudi Arabia Department of Computer Engineering College of Computers and Information TechnologyTaif UniversityTaif21944Saudi Arabia Department of Electronics Engineering Sudan University of Science and TechnologyKhartoum11111Sudan

In cognitive radio networks(CoR),the performance of cooperative spectrum sensing is improved by reducing the overall error rate or maximizing the detection *** optimization methods are usually used to optimize the number of user-chosen for cooperation and the threshold ***,these methods do not take into account the effect of sample size and its effect on improving CoR *** general,a large sample size results in more reliable detection,but takes longer sensing time and increases ***,the locally sensed sample size is an optimization ***,optimizing the local sample size for each cognitive user helps to improve CoR *** this study,two new methods are proposed to find the optimum sample size to achieve objective-based improved(single/double)threshold energy detection,these methods are the optimum sample size N^(*)and neural networks(NN)*** the evaluation,it was found that the proposed methods outperform the traditional sample size selection in terms of the total error rate,detection probability,and throughput.

关键词： Cognitive radio spectrum sensing energy detection double threshold neural network machine learning optimization quality of service

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Impact of COVID-19 on endourology surgical practice in Saudi Arabia:A national multicenter study

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Asian Journal of Urology 2021年第4期8卷 416-423页

作者： Abdel Raheem Ali Yahya Ghazwani Ibrahim Alowidah raed A.Azhar Mohammed Alomar Ahmed Alzahrani Ossamah Alsowayan Wissam Kamal Abdulrahman Alalayet Ahmad Bugis Abdulaziz MAlthunayan MAlzahrani Tarek Kamel Fadaak Aiman Al-Solumany saeed Bin Hamri Urology Department King Saud Medical CityRiyadhSaudi Arabia Urology Department Faculty of MedicineTanta UniversityTantaEgypt Devision of Urology King Abdullah International Medical Research CenterCollege of MedicineKing Abdulaziz Medical CityKing Saud Bin Abdulaziz University for Health ScienceDivision of UrologyKing Abdulaziz Medical CityRiyadhSaudi Arabia Urology Department Faculty of MedicineKing Abdulaziz UniversityJeddahSaudi Arabia Department of Surgery College of MedicineKing Saud University and King Saud University Medical CityRiyadhSaudi Arabia Urology Department Price Sultan Military Medical CityRiyadhSaudi Arabia Urology Department King Fahd HospitalImam Abdulrahman Bin Faisal UniversityDammamSaudi Arabia Urology Department King Fahd HospitalJeddahSaudi Arabia

Objective:To identify the impact of COVID-19 on endourology surgical practice in Saudi ***:A retrospective study of seven tertiary hospitals from January 2019 to April 2019,and from January 2020 to April 2020 was *** of urology outpatient department(OPD)visits and endourology procedures in the first third of 2020 were analyzed and compared with those in the first third of 2019,as well as,during the full curfew time,*** 2020 versus April ***:Number of OPD visits in the first third of 2020 and 2019 were 19499 and 26594,respectively(p75%,including OPD visits and elective endourology *** hospitals have changed their strategic preventive measures by increasing the rate of teleclinics and day surgeries.

关键词： COVID-19 Endourology Saudi Arabia

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