检索结果-南通市图书馆

Heterogeneous Expansion of End-moraine Dammed Lakes in the Hindukush-Karakoram-Himalaya Ranges of Pakistan during 2001-2013

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2015年第5期12卷 1113-1124页

作者： Arshad ashraf Rozina NAZ Muhammad Bilal IQBAL Climate Change Alternate Energy and Water Resources Institute (CAEWRI) National Agricultural Research Center

Global climate change during the twentieth century had a significant impact on the glaciers that resulted in creation of new lakes and expansion of existing ones, and ultimately an increase in the number of glacial lake outburst floods(GLOFs) in the Himalayan region. This study reports variation of the end-moraine dammed lakes in the high altitude Hindukush-Karakoram-Himalaya(HKH) region of Pakistan to evaluate future floods hazard under changing climate in this region. An integrated temporal remote sensing and Geographic information system(GIS) based approach using satellite images of Landsat-7 and 8 was adopted to detect 482 endmoraine dammed lakes out of which 339 lakes(>0.02 km2) were selected for temporal change analysis during the 2001-2013 period. The findings of the study revealed a net expansion in the end-moraine dammed lakes area in the Karakoram(about 7.7%) and in the Himalayas(4.6%), while there was a net shrinkage of about 1.5% in the lakes area in the Hindukush range during this period. The percentage increase in the lakes' area was highest above 4500 m asl in the Hindukush, within 3500-4000 m asl in the Himalayas and below 3500 m asl in the Karakoram range. The overall positive change in the lakes' area appears to prevail in various altitudinal ranges of the region. The heterogeneous areal changes in the endmoraine dammed lakes might be attributed to different climate regimes and glacial hydrodynamics in the three HKH ranges. A periodic monitoring of the glacial lakes and their associated glaciers is essential for developing effective hazard assessment and risk reduction strategies for this high altitude Himalayan region.

关键词： End-moraine glacial lakes GLOF Karakoram Himalayan region

Robust Stabilization of Load Frequency Control System Under Networked Environment

在线全文

学校读者我要写书评

暂无评论

International Journal of Automation and computing 2017年第1期14卷 93-105页

作者： ashraf Khalil Ji-Hong Wang Omar Mohamed Electrical and Electronics Engineering Department University of Benghazi Benghazi Libya School of Engineering University of Warwick Coventry UK King Abdullah Ⅱ Faculty of Engineering Princess Sumaya University of Technology Amman Jordan

The deregulation of the electricity market made the open communication infrastructure an exigent need for future power system. In this scenario dedicated communication links are replaced by shared networks. These shared networks are characterized by random time delay and data loss. The random time delay and data loss may lead to system instability if they are not considered during the controller design stage. Load frequency control systems used to rely on dedicated communication links. To meet future power system challenges these dedicated networks are replaced by open communication links which makes the system stochastic. In this paper, the stochastic stabilization of load frequency control system under networked environment is investigated. The shared network is represented by three states which are governed by Markov chains. A controller synthesis method based on the stochastic stability criteria is presented in the paper. A one-area load frequency control system is chosen as case study. The effectiveness of the proposed method for the controller synthesis is tested through simulation. The derived proportion integration （PI） controller proves to be optimum where it is a compromise between compensating the random time delay effects and degrading the system dynamic performance. The range of the PI controller gains that guarantee the stochastic stability is determined. Also the range of the PI controller gains that achieve the robust stochastic stability is determined where the decay rate is used to measure the robustness of the system.

关键词： Load frequency control load frequency control (LFC) Markov chains networked control system robust stabilization.

Triple Key Security Algorithm Against Single Key Attack on Multiple Rounds

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2022年第9期72卷 6061-6077页

作者： Muhammad Akram Muhammad Waseem Iqbal Syed ashraf Ali Muhammad Usman ashraf Khalid Alsubhi Hani Moaiteq Aljahdali Department of Computer Science Superior University Lahore54000Pakistan Department of Software Engineering Superior University Lahore54000Pakistan Department of Computer Science The Institute of Management Sciences(PAK-AIMS)Lahore54000Pakistan Department of Computer Science GC Women University SialkotPakistan Department of Computer Science King Abdulaziz UniversityJeddahSaudi Arabia Faculty of Computing and Information Technology King Abdulaziz UniversityJeddahSaudi Arabia

In cipher algorithms,the encryption and decryption are based on the same *** are some limitations in cipher algorithms,for example in polyalphabetic substitution cipher the key size must be equal to plaintext otherwise it will be repeated and if the key is known then encryption becomes *** paper aims to improve the said limitations by designing of Triple key security algorithm(TKS)in which the key is modified on polyalphabetic substitution cipher to maintain the size of the key and *** plaintext character is substituted by an alternative *** mode of substitution is transformed cyclically which depends on the current position of the modified *** keys are used in the encryption and decryption process on 8 or 16 rounds with the Exclusively-OR(XOR)of the 1st *** study also identifies a single-key attack on multiple rounds block cipher in mobile communications and applied the proposed technique to prevent the *** utilization of the TKS algorithm,the decryption is illustrated,and security is analyzed in detail with mathematical examples.

关键词： Encryption decryption cipher symmetric key cryptography single key attack

Are developing countries prepared to face Ebola-like outbreaks?

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Virologica Sinica 2015年第3期30卷 234-237页

作者： Aftab Ahmad Sadia ashraf Shoji Komai Graduate School of Biological Sciences Nara Institute of Science and Technology National Academy of Young Scientists (NAYS) Pakistan University of the Punjab

Ebola virus disease has caused havoc in West Africa,with 11,162deaths and more than 27,181 cases(as of May 31,2015)being reported since the virus emerged in early2014 in *** maximum number of cases has been reported in Sierra Leone(12,827),while most of the reported deaths have occurred in Liberia(4,806),according to the Center for Disease Control and

关键词： deaths Africa Sierra Sudan emerged infra officials infected http reservoir

MHD flow and heat transfer of micropolar fluid between two porous disks

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2012年第1期33卷 51-64页

作者： M. ashraf A. R. WEHGAL Centre for Advanced Studies in Pure and Applied Mathematics Bahauddin Zakariya University Department of Mathematics Stockholm University

A numerical study is carried out for the axisymmetric steady laminar incompressible flow of an electrically conducting micropolar fluid between two infinite parallel porous disks with the constant uniform injection through the surface of the disks. The fluid is subjected to an external transverse magnetic field. The governing nonlinear equations of motion are transformed into a dimensionless form through yon Karman＇s similarity transformation. An algorithm based on a finite difference scheme is used to solve the reduced coupled ordinary differential equations under associated boundary conditions. The effects of the Reynolds number, the magnetic parameter, the micropolar parameter, and the Prandtl number on the flow velocity and temperature distributions are discussed. The results agree well with those of the previously published work for special cases. The investigation predicts that the heat transfer rate at the surfaces of the disks increases with the increases in the Reynolds number, the magnetic parameter, and the Prandtl number. The shear stresses decrease with the increase in the injection while increase with the increase in the applied magnetic field. The shear stress factor is lower for micropolar fluids than for Newtonian fluids, which may be beneficial in the flow and thermal control in the polymeric processing.

关键词： MHD flow porous disk micropolar fluid heat transfer microrotation

New generalized fuzzy transform computations for solving fractional partial differential equations arising in oceanography

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean Engineering and Science 2023年第1期8卷 55-78页

作者： Saima Rashid Rehana ashraf Zakia Hammouch Department of Mathematics Government College UniversityFaisalabadPakistan Department of Mathematis Lahore College for Women UniversityLahorePakistan Division of Applied Mathematics Thu Dau Mot University Binh Duong ProvinceVietnam Department of Medical Research China Medical University HospitalTaichungTaiwan Department of Sciences Ecole Normal SuperieureMoulay Ismail University of Meknes50000 Morocco

This paper presents a study of nonlinear waves in shallow *** Korteweg-de Vries(KdV)equa-tion has a canonical version based on oceanography theory,the shallow water waves in the oceans,and the internal ion-acoustic waves in ***,the main goal of this investigation is to employ a semi-analytical method based on the homotopy perturbation transform method(HPTM)to obtain the numerical findings of nonlinear dispersive and fifth order KdV models for investigating the behaviour of magneto-acoustic waves in plasma via *** approach is connected with the fuzzy generalized integral transform and *** that,two novel results for fuzzy generalized integral transforma-tion concerning fuzzy partial gH-derivatives are *** illustrative examples are illustrated to show the effectiveness and supremacy of the proposed ***,2D and 3D simulations de-pict the comparison analysis between two fractional derivative operators(Caputo and Atangana-Baleanu fractional derivative operators in the Caputo sense)under generalized *** projected method(GHPTM)demonstrates a diverse spectrum of applications for dealing with nonlinear wave equa-tions in scientific *** current work,as a novel use of GHPTM,demonstrates some key differ-ences from existing similar methods.

关键词： Fuzzy set theory Hukuhara differentiability KdV Equation Generalized integral transform Caputo fractional derivative AB-Fractional operator Homotopy perturbation method

Appropriate teaching and learning strategies for the architectural design process in pedagogic design studios

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Architectural Research 2017年第2期6卷 204-217页

作者： ashraf M. Soliman Kingdom University Riffa Bahrain Minia University Minia Egypt

The national qualification framework of a country requires a certain level of knowledge and complexity of skills for an academic degree to be recognized. For architectural programs, student workload is heavy on design courses. Therefore, each course must be carefully developed to ensure that students are not overloaded. Teaching and learning strategies have different implications for courses, which occasionally result in overloading the students. This research aims to study the three main pillars of teaching and [earning strategies for each design phase in pedagogic design studios. The most appropriate model for each teaching and [earning strategy, including a set of the three main pillars, is then identified for each design phase. A practical strategy for managing design studios is also determined. The aforementioned three pillars are as follows： teaching and learning methods, assigned tasks or study aspects, and design communication techniques. Two research methods, namely, a literature review and a survey among design educators, are adopted. The literature review examines aspects that contribute to the design process and its phases, teaching methods, design skills, communication methods, and studio management strategies. On the basis of the literature review, the background of developments and practices in the design education process are used as constructive tools to develop the survey for design educators. Through the survey, the pillars of teaching and [earning strategies that are frequently practiced in design studios are evaluated. Results of this study are classified into three ranks using the nature break classification method for numerical values. Subsequently, three priority models that correspond to teaching and learning strategies, as welt as to the required skills and capabilities, are established. A group-based strategy with an interdisciplinary approach is also determined to be the most suitable technique for managing the pedagogy of architectural

关键词： Architectural design Studio teaching Learning strategy

μPMU-based smart adaptive protection scheme for microgrids

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2019年第4期7卷 887-898页

作者： Mohamed Salah ELBANA Nabil ABBASY ashraf MEGHED Nahil SHAKER Electrical Engineering Department Faculty of EngineeringAlexandria UniversityLotfy El-Sied St.P.O.ElhadaraAlexandria 21544Egypt

The concepts of microgrids(MGs)and smart grid represent the recent targeted revolution towards fully smart electrical network integrated with high penetration of renewable energy sources(RESs).The protection system of MGs becomes a challenge due to variable characteristics of its currents,bidirectional power flow and output power fluctuations of RES,causing selectivity and sensitivity issues for conventional protective devices(PDs)with fixed *** this paper,a smart protection scheme(SPS)is proposed using micro-phasor measurement units(μPMUs)to obtain the continuous rapid synchronized phasor measurement *** it is communicated with a microgrid central controller(MGCC)through highly reliable communication architecture to carry out online smart adaptive protection *** index coefficients and abnormality coefficients are calculated for each feeder to detect the fault location and the abnormality *** modeling of an MG including 10-bus connected distribution system with integrated distributed generation(DG)is simulated using ETAP *** proposed protection algorithm is modeled and evaluated using MATLAB *** proposed fault detector and abnormality detector can enable quick and accurate fault identification and isolation.

关键词： Fault index coefficients Microgrid(MG) Micro-phasor measurement unit(μPMU) Renewable energy source(RES) Smart protection scheme(SPS)

Comparison of outcomes between early and delayed weight bearing following lower limb free flaps:an 18-month single-center study

在线全文

学校读者我要写书评

暂无评论

Plastic and Aesthetic Research 2023年第1期10卷 656-662页

作者： Majid Al-Khalil Manuela Roman Ahmed emam Nicholas Marsden Welsh Centre for Burns&Plastic Surgery Morriston HospitalSwansea SA66NLUnited Kingdom Major Trauma Centre University Hospital of WalesCardiff CF144XWUnited Kingdom

Aim:Post-operative protocols following lower limb free flap surgery are not well defined,with a lack of consensus in the literature around limb dependency and weight *** aim was to compare the complication rate for lower limb free flaps before and after the introduction of an enhanced lower limb free flap protocol with earlier dangling(day 3 *** 4)and weight bearing(day 5 *** 14)post lower limb free flap ***:All lower limb free flaps between June 2020-January 2022 were identified from a departmental flap *** data were collected from the comprehensive lower limb free flap database,medical notes,and electronic *** prescribed an extended non-weight-bearing period due to the method of bone fixation were ***:A total of 37 patients,15 pre-and 22 post-enhanced protocol,were identified for *** mean age was 43(17-72)with a M:F of 3:*** was no difference in the type of flap reconstruction between groups,with the anterolateral thigh flap being the most common in both *** differences were identified in the number of complications related to dependency/weight bearing before and after the introduction of the enhanced protocol,with the mean length of stay reduced from 12.1 to 10.6 days(P=0.34).Conclusion:The new enhanced protocol remains the standard of care in our unit,as we demonstrated a reduction in length of stay with no difference in complication rates following early weight bearing after lower limb free flap surgery.

关键词： Lower limb reconstruction free flap free tissue transfer weight bearing post-operative complications