检索结果-南通市图书馆

An Efficient Smoothing and Thresholding Image Segmentation Framework with Weighted Anisotropic-Isotropic Total Variation

在线全文

学校读者我要写书评

暂无评论

Communications on Applied Mathematics and Computation 2024年第2期6卷 1369-1405页

作者： kevin bui Yifei Lou Fredrick park Jack Xin Department of Mathematics University of CaliforniaIrvineIrvineCA 92697-3875USA Department of Mathematics University of North CarolinaChapel HillChapel HillNC 27599.USA Department of Mathematics and Computer Science Whittier CollegeWhittierCA 90602USA

In this paper,we design an efficient,multi-stage image segmentation framework that incorporates a weighted difference of anisotropic and isotropic total variation(AITV).The segmentation framework generally consists of two stages:smoothing and thresholding,thus referred to as smoothing-and-thresholding(SaT).In the first stage,a smoothed image is obtained by an AITV-regularized Mumford-Shah(MS)model,which can be solved efficiently by the alternating direction method of multipliers(ADMMs)with a closed-form solution of a proximal operator of the l_(1)-αl_(2) *** convergence of the ADMM algorithm is *** the second stage,we threshold the smoothed image by K-means clustering to obtain the final segmentation *** experiments demonstrate that the proposed segmentation framework is versatile for both grayscale and color images,effcient in producing high-quality segmentation results within a few seconds,and robust to input images that are corrupted with noise,blur,or *** compare the AITV method with its original convex TV and nonconvex TVP(O

关键词： Image segmentation Non-convex optimization Mumford-Shah(MS)model Alternating direction method of multipliers(ADMMs) Proximal operator

Network Log-based SSH brute-Force Attack Detection Model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2021年第7期68卷 887-901页

作者： Jeonghoon park Jinsu Kim b.b.Gupta Namje park Department of Convergence Information Security Graduate SchoolJeju National UniversityJeju63243Korea Department of Computer Engineering National Institute of Technology KurukshetraKurukshetra136119India

The rapid advancement of IT technology has enabled the quick discovery,sharing and collection of quality information,but has also increased cyberattacks at a fast pace at the same *** exists no means to block these cyberattacks completely,and all security policies need to consider the possibility of external ***,it is crucial to reduce external attacks through preventative *** general,since routers located in the upper part of a firewall can hardly be protected by security systems,they are exposed to numerous unblocked *** block unnecessary services and accept necessary ones while taking appropriate measures to reduce vulnerability,block unauthorized access,and generate relevant *** logs created through unauthorized access are caused by SSH brute-force attacks,and therefore IP data of the attack can be collected through the *** paper proposes a model to detect SSH brute-force attacks through their logs,collect their IP address,and control access from that IP *** this paper,we present a model that extracts and fragments the specific data required from the packets of collected routers in order to detect indiscriminate SSH input *** do so,the model multiplies a user’s access records in each packet by weights and adds them to the blacklist according to a final calculated result *** addition,the model can specify the internal IP of an attack attempt and defend against the first 29 destination IP addresses attempting the attack.

关键词： SSH brute-force attack ELK Stack IT infra log access control

Habitat selection by nestbox-breeding birds and Roe Deer are incongruent within a heterogeneous woodland landscape

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Avian Research 2022年第1期13卷 43-48页

作者： kevin b.briggs Mark C.Mainwaring Warton CarnforthLancashireLA59RAUK Field Research Station at Fort Missoula Division of Biological SciencesUniversity of MontanaMissoulaMT59812USA

Conserving species relies upon acquiring an understanding of their use of habitat,yet our understanding of the use of habitat by co-existing species of different guilds at microgeographic scales remains *** particular,the use of habitat by woodland species is of conservation concern because of widespread declines in woodland *** bird declines have been ascribed,in part,to high deer densities because their browsing reduces the availability of nesting sites and *** quantify the microgeographic use of habitat by Roe Deer(Capreolus capreolus)and of Great Tits(Parus major),blue Tits(Cyanistes caeruleus)and Pied Flycatchers(Ficedula hypoleuca)in a heterogenous woodland *** examined the use of habitat at microgeographic scales by the deer and the three bird species in relation to whether the local habitat was flat or wet or had a path,fence or wall within a 25-m radius of 206 randomly selected *** first examined if the occupancy rates of nestboxes in those locations were correlated with the number of Roe Deer lays and second,examined if the use of habitat by the Roe Deer and the bird species were associated with each of the habitat features that we *** begin by showing that the use of habitat by Roe Deer is incongruent with the use of habitat by Great Tits,blue Tits and Pied Flycatchers during the breeding ***,whilst all three bird species showed no,or weak,habitat preferences,the Roe Deer preferred daytime lay sites that were in flat areas of wet woodland close to paths,whilst there were no significant effects of the presence of fences and *** findings show that the Roe Deer and the three bird species differ in the use of habitat within a heterogenous woodland landscape,meaning that their use of habitat did not overlap at microgeographic ***,the deer showed preferences for flat areas of wet woodland,whilst none of the bird species exhibited such preferences,and we discuss the implications o

关键词： Capreolus capreolus Cyanistes caeruleus Ficedula hypoleuca Habitat use Nestboxes Nest site selection Parus major Woodlands

Microstructure and creep properties of Mg-4Al-2Sn-1(Ca,Sr) alloys

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2010年第7期20卷 1184-1191页

作者： b.H.KIM K.C.park Y.H.park I.M.park Department of Material Science and Engineering Pusan National UniversitySan 30 Jangjeon-dongGeumjeong-guBusan 609-735Korea

The effects of Ca and Sr addition on the microstructure and creep properties of Mg-4Al-2Sn alloys were examined. Tensile tests at 25 ℃ and 200 ℃ and creep tests at 150 ℃ and 200 ℃ were carried out to estimate the room temperature and high temperature mechanical properties of these alloys. The microstrueture of the Mg-4Al-2Sn alloy showed dendritic a-Mg, Mg17Al12 and Mg2Sn phases. The latter two phases precipitated along the grain boundaries. The addition of Ca and Sr resulted in the formation of ternary CaMgSn and SrMgSn phases within the grain. The grain size was reduced slightly with the addition of Sr and Ca. The tensile strength was decreased by the addition of Ca and Sr at room temperature. However, the high temperature tensile strength was increased. The creep strength was improved by the addition of Ca and Sr.

关键词： magnesium alloys Ca Sr void initiation mechanical properties creep mechanism

The effects of sun exposure on carotenoid accumulation and oxidative stress in the retina of the House Finch(Haemorhous mexicanus)

在线全文

学校读者我要写书评

暂无评论

Chinese birds 2016年第1期7卷 56-67页

作者： Matthew b.Toomey kevin J.McGraw School of Life Sciences Arizona State University Department of Pathology and Immunology Washington University Medical School

background: Diet-derived carotenoid pigments are concentrated in the retinas of birds and serve a variety of functions, including photoprotection. In domesticated bird species(e.g., chickens and quail), retinal carotenoid pigmentation has been shown to respond to large manipulations in light exposure and provide protection against photodamage. However, it is not known if or how wild birds respond to ecologically relevant variation in sun ***: We manipulated the duration of natural sunlight exposure and dietary carotenoid levels in wild-caught captive House Finches(Haemorhous mexicanus), then measured carotenoid accumulation and oxidative stress in the ***: We found no significant effects of sun exposure on retinal levels of carotenoids or lipid peroxidation, in replicate experiments, in winter(Jan–Mar) and spring/summer(May–June). Dietary carotenoid supplementation in the spring/summer experiment led to significantly higher retinal carotenoid levels, but did not affect lipid peroxidation. Carotenoid levels differed significantly between the winter and spring/summer experiments, with higher retinal and lower plasma carotenoid levels in birds from the later ***: Our results suggest that variation in the duration of exposure to direct sunlight have limited influence on intraspecific variation in retinal carotenoid accumulation, but that accumulation may track other seasonal–environmental cues and physiological processes.

关键词： Carotenoids Haemorhous mexicanus House Finch Photostress Vision

Evaluation of microstructure and mechanical properties of Mg-xCe-0.5Zn alloys by nano-indentation

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2010年第7期20卷 1240-1243页

作者： K.C.park b.H.KIM Y.H.park I.M.park Department of Material Science and Engineering Pusan National UniversitySan 30 Jangjeon-dongGeumjeong-guBusan 609-735Korea

The microstructure and mechanical properties of Mg-xCe-0.5Zn （x=0.5, 1.5, 2.5, molar fraction, %） alloys were examined using a nano-indentation technique. The alloys were fabricated using a vacuum induction melting method under an argon atmosphere The microstruetures of Mg-xCe-0.5Zn alloys mainly consist ofa-Mg and eutectic Mg12Ce phase. The volume fraction and size of the eutectic Mgl2Ce phase increase with increasing Ce contents. Nano-indentation test results show that the indentation hardness and elastic modulus of the eutectic Mg12Ce phase are higher than those of the a-Mg matrix. In addition, the mean indentation hardness and elastic modulus of the Mg-xCe-0.5Zn alloys increase with the Ce addition amount increasing.

关键词： Mg alloys Mg-Ce-Zn rare earth microstructure mechanical properties nano-indentation

Deposition of Nano-Scaled Coatings Using Inductively Coupled Plasma

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2004年第Z2期22卷 153-156页

作者： D H Jung b park J J Lee School of Materials Science and Engineering College of EngineeringSeoul National UniversitySeoul 151-744Korea School of Materials Science and EngineeringCollege of EngineeringSeoul National UniversitySeoul 151-744Korea School of Materials Science and EngineeringCollege of EngineeringSeoul National UniversitySeoul 151-744Korea

Nano-scaled Ti-b-N coatings could be produced by inductively coupled plasma (ICP) assisted magnetron spurtering. The properties and microstructure of the coating can be changed drastically by applying ICP to conventional magnetron sputtering. In this work, an internal type rf ICP process is used. The core of this technology is the efficient production and control of self-depositing ions and reactive gas ions by an induced electric field. Ti-b-N coatings were prepared by using a Tib2 target and a gas mixture of N2 and Ar at 200 ℃ and a pressure of 60 mTorr. In addition to ICP, the effect of the substrate bias voltage on the structure and properties of the coating was investigated. by applying ICP and a bias voltage to the substrate the hardness of the Ti-b-N coating is increased by more than 75 GPa, as a result of enhanced ionization in the plasma. The Ti-b-N coating, which has the highest hardness, shows the best surface uniformity and a very dense structure with a grain size of 3 nm. This sample also shows a high crystallinity compared to the coating prepared using other deposition parameters.

关键词： nano-scaled coatings industively conpled plasma

Expanding beyond canonical metabolism:Interfacing alternative elements,synthetic biology,and metabolic engineering

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Synthetic and Systems biotechnology 2018年第1期3卷 20-33页

作者： kevin b.Reed Hal S.Alper McKetta Department of Chemical Engineering The University of Texas at Austin200E Dean Keeton St.Stop C0400AustinTX 78712USA Institute for Cellular and Molecular biology The University of Texas at Austin2500 Speedway AvenueAustinTX 78712USA

Metabolic engineering offers an exquisite capacity to produce new molecules in a renewable ***,most industrial applications have focused on only a small subset of elements from the periodic table,centered around carbon *** review aims to illustrate the expanse of chemical elements that can currently(and potentially)be integrated into useful products using cellular ***,we describe recent advances in expanding the cellular scope to include the halogens,selenium and the metalloids,and a variety of metal *** examples range from small molecules,heteroatom-linked uncommon elements,and natural products to biomining and nanotechnology ***,this review covers the promise of an expanded range of elemental incorporations and the future impacts it may have on biotechnology.

关键词： Metabolic engineering Synthetic biology Unnatural metabolism Halogenation Cellular factories Non-canonical elements

Fuel Economy Impacts of Manual,Conventional Cruise Control,and Predictive Eco-Cruise Control Driving

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Transportation Science and Technology 2013年第3期2卷 227-242页

作者： Sangjun park Hesham A.Rakha Kyoungho Ahn kevin Moran Department of Civil Engineering Chosun University 309 Pilmun-daero Dong-gu Gwangju 501-759South Korea Center for Sustainable Mobility Virginia Tech Transportation Institute 3500 Transportation Research PlazaBlacksburgVA 24061 Nokia Location and Commerce 425 West Randolph Street ChicagoIL 60606

The paper presents the results of a field experiment that was designed to compare manual driving,conventional cruise control(CCC)driving,and Eco-cruise control(ECC)driving with regard to fuel *** field experiment was conducted on five test vehicles along a section of Interstate 81 that was comprised of±4%uphill and downhill grade *** an Onboard Diagnostic II reader,instantaneous fuel consumption rates and other driving parameters were collected with and without the CCC system *** collected data were compared with regard to fuel economy,throttle control,and travel *** results demonstrate that CCC enhances vehicle fuel economy by 3.3 percent on average relative to manual driving,however this difference was not found to be statistically significant at a 5 percent significance *** results demonstrate that CCC driving is more efficient on downhill versus uphill *** addition,the study demonstrates that an ECC system can produce fuel savings ranging between 8 and 16 percent with increases in travel times ranging between 3 and 6 *** benefits appear to be largest for heavier vehicles(SUVs).

关键词： Cruise driving travel