检索结果-南通市图书馆

AN M/M/C RETRIAL QUEUEING SYSTEM WITH bERNOULLI VACATIONS

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science and Systems Engineering 2009年第2期18卷 222-242页

作者： b.krishna KUMAR R.RUKMANI V.THANGARAJ Department of Mathematics College of EngineeringAnna UniversityChennai600 025India Department of Mathematics Pachaiyappa's CollegeChennai600030India Ramanujan Institute for Advanced Study in Mathematics University of MadrasChennai600 005India

In this paper, a steady-state Markovian multi-server retrial queueing system with bernoulli vacation scheduling service is studied. Using matrix-geometric approach, various interesting and important system performance measures are obtained. Further, the probability descriptors like ideal retrial and vain retrial are provided. Finally, extensive numerical illustrations are presented to indicate the quantifying nature of the approach to obtain solutions to this queueing system.

关键词： Retrial queue bernoulli vacation matrix-geometric methods busy period vain retrial ideal retrial

How does the stand structure of treeline-forming species shape the treeline ecotone in different regions of the Nepal Himalayas?

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2020年第10期17卷 2354-2368页

作者： Parveen K.CHHETRI Raju bISTA krishna b.SHRESTHA Department of Earth Science and Geography California State UniversityDominguez HillsCarsonCalifornia90747USA Department of biological Sciences University of BergenPO Box 7803N-5020BergenNorway

Stand structure dynamics are considered as major happenings in any forest as a response to environmental ***,this important topic is underrepresented in the treeline studies in the Nepal *** aimed to investigate site-as well as species-specific changes in morphometric features(basal diameter,crown cover,density,and height)along the elevational gradient across treeline ecotones in response to recent environmental *** stand structure characteristics of Abies spectabilis,Pinus wallichiana,and betula utilis across the treeline ecotone of three study sites in Eastern(barun),Central(Manang),and Western(Dhorpatan)Nepal were analyzed to elucidate structural ***,eight transects(20 m×(60–250 m))across the treeline ecotone were *** of all life forms,trees(>2 m),saplings(0.5–2 m),and seedlings(basal area increment was higher in barun,but the Manang treeline,despite profound regeneration in recent years,had a low annual basal area ***,the altitudinal distribution of age and morphometry were not consistent among those ***,intra-specific competition was not *** site-specific stand structure dynamics explain why treelines do not respond uniformly to increasing *** invokes,in further studies,the incorporation of the tree’s morphometric adaptation traits,phenotypic plasticity,and interactions between species genotype and the environment.

关键词： Climate change Morphometry Nepal Himalayas Stand structure Treeline Tree-rings

Recent treeline dynamics are similar between dry and mesic areas of Nepal, central Himalaya

在线全文

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2015年第4期8卷 347-358页

作者： krishna b.Shrestha Annika Hofgaard Vigdis Vandvik Department of biology University of BergenPO Box 7803NO-5020BergenNorway Uib Global University of BergenJekteviksbakken 31PO Box 7800NO-5020BergenNorway Norwegian Institute for Nature Research PO Box 5685 SluppenNO-7485TrondheimNorway

Aims We investigated the treeline dynamics of two environmentally con-trasting areas in the Nepalese Himalaya to address the following questions:(i)Does the timing of establishment of the current tree-line differ between the two study areas,and can area-specific tree-line developments be identified?(ii)Do recruitment patterns and height growth indicate recent climate-driven treeline advance,fol-lowing the general prediction for the central Himalayan region,in the two study areas?Methods a dry-climate treeline dominated by Pinus wallichiana and a mesic-climate treeline with Abies spectabilis were selected for *** each area,we sampled the size and age structure of the study spe-cies along three elevational transects(20-m wide)from the forest line to the tree species line crossing the *** also sampled treeline trees from within and outside transects to reconstruct past treeline establishment *** Findings Despite differences in moisture regimes,tree species and recent climate trends,our two study areas showed very similar treeline dynamics over the past six *** both areas,the recruitment of treeline trees indicates stationary treelines over the past six decades with the current treelines being dominated by trees that were established around *** mesic area has experienced an overall climatic warming trend,and the stationary Abies treeline is hypothesized to be regulated by non-climatic factors,notably *** dry area has not experienced warming but increased climatic variability and some very cool summers in the recent dec-ades may explain the stationary to weakly receding Pinus treeline,which appears more climatically controlled with decreased recruit-ment over the past decades and decreased growth towards higher *** both areas,there is a potential for treeline advance,depending on future land use and climate *** results highlight the importance of conducting treeline ecotone analyses for several sites or are

关键词： Abies spectabilis Himalaya Pinus wallichiana slope aspect treeline ecotone dynamics

bRUCK FORMULA FOR A PERTURbED LIPSCHITZIAN ITERATION OF LIPSCHITZ PSEUDOCONTRACTIVE MAPS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2005年第11期26卷 1427-1434页

作者： krishna Kumar b. K. Sharma ZHOU Zhe-wei School of Studies in Mathematics Pt. Ravishankar Shukla University Raipur Chhattisgarh-492010 India 不详

The solution to evolution equations has developed an independent theory within nonlinear analysis dealing with the existence and approximation of such solution （ fixed point） of pseudocontractive operators and its variants. The object is to introduce a perturbed iteration method for proving the convergence of sequence of Lipschitzian pseudocontractive mapping using approximate fixed point technique. This iteration can be ued for nonlinear operators which are more general than Lipschitzian pseudocontractive operator and bruck iteration fails for proving their convergence. Our results generalize the results of Chidume and Zegeye.

关键词： pseudocontractive map perturbed Lipschitzian iteration fixed point uniformaly Gateaux differential norm

Facile one-step hydrothermal route to MSe/Mo_(3)Se_(4)(M:Zn,Mn,and Ni)-based electrode materials for ultralong-life hybrid supercapacitors

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第25期156卷 230-240页

作者： b.N.Vamsi krishna Obula Reddy Ankinapalli Ayyaluri Ramakrishna Reddy Jae Su Yu Department of Electronics and Information Convergence Engineering Institute for Wearable Convergence ElectronicsKyung Hee UniversityYongin-siGyeonggi-do 17104Republic of Korea

Transition metal selenides have attracted great interest in electrochemical energy storage applications because of their good electrochemical activity and conductivity ***,we reported the metal molybdenum selenide(M Se/Mo_(3)Se_(4)(M:Zn,Mn,and Ni))electrode materials on their morphological and electrochemical properties by varying the metal ions via a facile hydrothermal *** effects of the structural,morphological,and surface area properties of the prepared powder materials on their electrochemical performance were *** to the hierarchical porous and unique interconnected structure,the nickel molybdenum selenide nanosheet spheres(NMS NSSs)-based electrode material delivered an excellent specific capacity value of 252 mAh g^(-1) at a current density of 1 Ag^(-1).Moreover,the optimized NMS NSSs electrode exhibited outstanding cycling stability with a capacity retention of 80%and a corresponding coulombic efficiency of 99%after 80,000 ***,a pouch-type hybrid supercapacitor(HSC)device was assembled using NMS NSSs material as a positive electrode and activated carbon as a negative electrode in 1 M aqueous KOH ***,the assembled HSC device exhibited superior energy and power density values as well as magnificent cycling *** real-time practical applications,light-emitting diodes and a digital display were powered using two series-connected HSC ***,the obtained tremendous results strongly suggest that the NiSe/Mo_(3)Se_(4) NSSs-based materials could be a promising electrode for ultralong-life energy storage applications.

关键词： Nickel selenides Molybdenum selenides Nanosheet spheres Ultralong-life cycling stability

Topography and human disturbances are major controlling factors in treeline pattern at barun and Manang area in the Nepal Himalaya

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 Mountain Science 2017年第1期14卷 119-127页

作者： Parveen K.CHHETRI krishna b.SHRESTHA David M.CAIRNS Department of Geography Texas A&M University College Station TX 77840 USA Uib Global Jekteviksbakken 31 PO Box 7800 5020 Bergen Norway

The alpine treeline ecotone is an important component of mountain ecosystems of the Nepal Himalaya; it plays a vital role in the livelihood of indigenous people,and provides ecosystem services. However,the region faces a problem of paucity of data on treeline characteristics at the regional and landscape scales. Therefore,we used Remote Sensing(RS),and Geographic Information Science(GIS) approaches to investigate cross-scale interactions in the treeline ecotone. Additionally,European Space Agency land cover map,International Center for Integrated Mountain Development(ICIMOD) land cover map,ecological map of Nepal,and United States Geological Survey Shuttle Radar Topography Mission-Digital Elevation Model were used to analyze treeline pattern at the regional scale. Digital Globe high-resolution satellite imagery of barun(eastern Nepal) and Manang(central Nepal) were used to study treeline patterns at the landscape scale. Treeline elevation ranges from 3300-4300 m above sea level. Abies spectabilis,betula utilis,and Pinus wallichiana are the main treeline-forming species in the Nepal Himalaya. There is an east to west treeline elevationgradient at the regional scale. No slope exposure is observed at the regional scale; however,at the landscape scale,slope exposure is present only in a disturbed area(Manang). Topography and human disturbance are the main treeline controlling factor in barun and Manang respectively.

关键词： Alpine Treeline Mountain ecosystem Himalaya Remote Sensing(RS) Geographic Information Science(GIS)

Oscillation Frequencyof𝐵and b𝐵Mesons in a QCD Potential Model with Relativistic Effects

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2011年第10期28卷 55-57页

作者： krishna Kingkar Pathak DKChoudhury Department of Physics Arya Vidyapeeth CollegeGuwahati-781016India Department of Physics Gauhati UniversityGuwahati-781014India

Wavefunction at the origin,with the incorporation of a relativistic effect,leads to singularity in a specific potential *** regularize the wavefunction,we introduced a short distance scale and used it to estimate the mass and decay constants of bd and bs mesons within the QCD potential *** values were then used to compute the oscillation frequency,Δmb,of bd and bs *** values were found to be in good agreement with experimental and other theoretical values.

关键词： meson singularity QCD

Chemical reaction effect of an axisymmetric flow over radially stretched sheet

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Propulsion and Power Research 2019年第1期8卷 79-84页

作者： b.Nayak S.R.Mishra G.Gopi krishna Department of Mathematics Sikslia‘O’AnusandhanKhandagiriBhubaneswar 751030OdisaIndia Department of Mathematics Sri Venkateswara UniversityTirupatiIndia

A steady boundary layer flow over a porous flat plate has been considered in the present *** transfer analysis with first order chemical reaction is also considered instead of heat *** plate concentration is considered in the form of power law instead of taking *** goveming PDEs are transformed into ordinary differential equations using similarity transfomation and then these ODEs are solved by employing Runge-Kutta fourth order method associated with shooting technique.A parametric study of all involving parameters is obtained by the help of *** major findings are:(i)the concentration of the fluid in its boundary layer decrease with increase in heavier species,the reaction rate parameter and the power law exponent;(ji)the rate of mass transfer increases with an increase in reaction rafe parameter and power-law exponent.

关键词： Magnetohydrodynamic Mass transfer First order chemical reaction Runge-Kutta method Shooting technique

Software for automated classification of probe-based confocal laser endomicroscopy videos of colorectal polyps

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2012年第39期18卷 5560-5569页

作者： barbara André Tom Vercauteren Anna M buchner Murli krishna Nicholas Ayache Michael b Wallace Image Computing Group Mauna Kea Technologies75010 ParisFrance Asclepios Research Team The National Institute for Research in Computer Science and Control Sophia Antipolis06902 Sophia AntipolisFrance Division of Gastroenterology Hospital of theUniversity of PennsylvaniaPhiladelphiaPA 19104United States Laboratory Medicine and Pathology Mayo Clinic Hospital in JacksonvilleJacksonvilleFL 3224United States Department of Gastroenterology and Hepatology Mayo Clinic Hospital in JacksonvilleJacksonvilleFL 3224United States

AIM:To support probe-based confocal laser endomi-croscopy (pCLE) diagnosis by designing software for the automated classification of colonic polyps. METHODS:Intravenous fluorescein pCLE imaging of colorectal lesions was performed on patients under-going screening and surveillance colonoscopies, followed by polypectomies. All resected specimens were reviewed by a reference gastrointestinal pathologist blinded to pCLE information. Histopathology was used as the criterion standard for the differentiation between neoplastic and non-neoplastic lesions. The pCLE video sequences, recorded for each polyp, were analyzed off-line by 2 expert endoscopists who were blinded to the endoscopic characteristics and histopathology. These pCLE videos, along with their histopathology diagnosis, were used to train the automated classification software which is a content-based image retrieval technique followed by k-nearest neighbor classification. The performance of the off-line diagnosis of pCLE videos established by the 2 expert endoscopists was compared with that of automated pCLE software classification. All evaluations were performed using leave-one-patient- out cross-validation to avoid bias. RESULTS:Colorectal lesions (135) were imaged in 71 patients. based on histopathology, 93 of these 135 lesions were neoplastic and 42 were non-neoplastic. The study found no statistical significance for the difference between the performance of automated pCLE software classification (accuracy 89.6%, sensitivity 92.5%, specificity 83.3%, using leave-one-patient-out cross-validation) and the performance of the off-line diagnosis of pCLE videos established by the 2 expert endoscopists (accuracy 89.6%, sensitivity 91.4%, specificity 85.7%). There was very low power (bserved differences. The 95% confidence intervals for equivalence testing were:-0.073 to 0.073 for accuracy, -0.068 to 0.089 for sensitivity and -0.18 to 0.13 for specificity. The classification software proposed i

关键词： Colorectal neoplasia Computer-aided diag-nosis Content-based image retrieval Nearest neigh-bor classification software Probe-based confocal laserendomicroscopy