检索结果-南通市图书馆

作者： lancine camara 湖南大学

学位级别：硕士

互联网的发展极大地促进了图片,音频,视频等数字媒体的广泛使用。图像可以被无限制的复制而没有任何质量损失。这样就带来数字图像安全问题。渐渐的,人们在数字图像中嵌入一些信息甚至于秘密信息,这些信息具有增值功能或者涉及到秘密通... 详细信息

互联网的发展极大地促进了图片,音频,视频等数字媒体的广泛使用。图像可以被无限制的复制而没有任何质量损失。这样就带来数字图像安全问题。渐渐的,人们在数字图像中嵌入一些信息甚至于秘密信息,这些信息具有增值功能或者涉及到秘密通信。这样,产生了一种通过在多媒体中直接嵌入一个具有鲁棒性的信号来保护数字媒体的新技术:数字水印。数字水印技术的产生为数字媒体的保护问题提供了一种前途广泛的方式。水印方案的分类作为一种重要的规范,是按照水印嵌入和提取所需的信息分类的:●可见水印的嵌入需要有原始图像和密钥。●半可见水印需要密钥和水印。●不可见水印仅仅需要密钥,这是水印系统最具挑战的技术。水印方案是嵌入可见还是不可见的水印。可见水印用于阻止非授权用户使用图像,易于检测。不可见水印用于识别其宿主数据的拥有者或原始数据。数字水印有如下应用:●版权保护:数字水印技术用于知识产权保护,且是最广泛的应用。●指纹识别:用于跟踪非法复本的来源。●拷贝保护:水印中嵌入的信息可以直接保护数字录音以防拷贝。●广播监控器:将水印信息嵌入商业广告,自动监控系统可以核实其广告是否被正常播放。●数据鉴定:如果原始数据非常重要,脆弱水印可以用于检查数据的真实性。●索引:搜索引擎可以将制作者和评论插入到视频邮件索引,电影索引,新闻索引用于搜索。●医学安全:将病人的名字和相关数据嵌入到医学图像中,是一种有用的安全措施。●数据隐藏:水印技术可以用于秘密信息的传输。传统的信息隐藏办法是加密技术。在数据传送之前,只允许密钥持有者解密数据。但是,这种办法在很大程度上依赖于图像的格式。当图像格式在传送过程中改变,加密信息将会被移除,这种方法就会失效。而且,一旦信息被加密,较难使它重新生成或者重新传送。另一种技术叫做信息隐藏技术,这种技术将多媒体数据作为载体,将秘密信息隐藏在这些多媒体数据中,并且保持多媒体数据本省的形态。但是,这种技术依赖于安全的通信环境,例如点多点通信,这种通信对第三者是非透明的。这种技术对于多种攻击不具有鲁棒性。水印技术由信息隐藏技术发展而来,但是又不同于信息隐藏技术。通过水印嵌入到多媒体中的信息是和其载体的格式相同的。而信息隐藏技术有时嵌入的信息和其载体毫无关系。而且,水印技术更加注重对多种攻击的鲁棒性。●鲁棒性水印技术的基本要求有:●感知性:利用人类视觉特点,确保在典型查看条件下水印不可见。这意味着一幅嵌入水印的图像和未嵌入水印的图像没有视觉上的不同。●鲁棒性:在被压缩攻击之后水印仍然可以被检测到。●容量:水印的容量指隐藏信息的长度或原始信号的有效载荷。●水印的有效载荷:指在特殊的数据流中实际可以存储的信息量。这个要求很大程度上依赖于宿主媒体,应用目的和预期质量。●安全性:水印安全性应基于Kerchhoff的假设,他假设加密数据者应该认为加密算法对非授权者是公开的。这意味着,水印安全可以解释为直接加密,安全领先的原则,它主要在于所选择的嵌入密钥。●特殊性:水印应该是普通的,适用于图像和声音视频等多种媒体。实际上并非如此,在多种应用中,基本的概念可能是相同的,但一种水印并非适应于所有的应用。到目前为止,已经发展有多种水印技术。这些技术将水印嵌入到空间域或频率域。早期的水印技术应用于空间域,在空间域中,将水印信息直接加到图像的像素值中。频率域是用于分析信号数学变换。在一些文章中,已经成功的应用了DWT和DCT。本文中,提出了一种数据隐藏技术,将秘密信息嵌入到512*512大小Lena图像中,并结合DWT和DCT作为我们的水印策略。首先使用小波变换得到4个子带,然后将变换后的HL分成8×8的块,对每个块进行DCT变换。对于水印的嵌入,将0和1水印嵌入到每个块变换块的中频。本文方法经证明可以通过产生高保真水印图像,从而对一些信号处理的攻击,例如JPEG压缩攻击,噪音攻击,几何旋转和中值滤波攻击等具有较好抵抗性。计算原始图像和嵌入水印的图像之间的峰值信噪比(PSNR),从结果辨别不出水印图像。提出不可见,不可感知和鲁棒性结合的,基于DWT-DCT的水印嵌入算法,来在数字图像中嵌入一些信息,提取水印,或者隐藏信息。该水印算法结合DWT和DCT,并且结合现存的各种水印算法中的各种有利因素。实验结果显示本文所提的水印嵌入方法对各种信号处理和压缩攻击均具有较好的鲁棒性。

关键词： Digital image watermarking frequency domain watermarking Discrete Wavelet Transform (DWT) Discrete Cosine Transform (DCT)

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Effects of seismic devices on transverse responses of piers in the Sutong Bridge

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Earthquake Engineering and Engineering Vibration 2015年第4期14卷 611-623页

作者： Shen Xing Alfredo camara Ye Aijun State Key Laboratory for Disaster Reduction in Civil Engineering Tongji University Department of Civil and Engineering City UniversityLondonUnited Kingdom PhD

The Sutong Bridge in China opened to traffic in 2008, and is an arterial connection between the cities of Nantong and Suzhou. It is a cable-stayed bridge with a main span of 1,088 m. Due to a tight construction schedule and lack of suitable seismic devices at the time, fixed supports were installed between the piers and the girder in the transverse direction. As a result, significant transverse seismic forces could occur in the piers and foundations, especially during a return period of a 2500-year earthquake. Therefore, the piers, foundations and fixed bearings had to be designed extraordinarily strong. However, when larger earthquakes occur, the bearings, piers and foundations are still vulnerable. The recent rapid developments in seismic technology and the performance-based design approach offer a better opportunity to optimize the transverse seismic design for the Sutong Bridge piers. The optimized design can be applied to the Sutong Bridge(as a retrofit), as well as other bridges. Seismic design alternatives utilizing viscous fluid dampers(VFD), or friction pendulum sliding bearings(FPSB), or transverse yielding metallic dampers(TYMD) are thoroughly studied in this work, and the results are compared with those from the current condition with fixed transverse supports and a hypothetical condition in which only sliding bearings are provided on top of the piers(the girder can move "freely" in the transverse direction during the earthquake, except for frictional forces of the sliding bearings). Parametric analyses were performed to optimize the design of these proposed seismic devices. From the comparison of the peak bridge responses in these configurations, it was found that both VFD and TYMD are very effective in the reduction of transverse seismic forces in piers, while at the same time keeping the relative transverse displacements between piers and the box girder within acceptable limits. However, compared to VFD, TYMD do not interact with the longitudinal disp

关键词： Sutong Bridge cable-stayed bridge seismic devices transverse response bridge piers viscous fluid dampers(VFD) friction pendulum sliding bearings(FPSB) transverse yielding metallic dampers(TYMD)

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Remote ischemic preconditioning as treatment for non-ischemic gastrointestinal disorders: Beyond ischemia-reperfusion injury

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World Journal of Gastroenterology 2014年第13期20卷 3572-3581页

作者： Carlos Rodrigo camara-Lemarroy Departamento de Medicina Interna Hospital Universitario "Dr. José E. González"Universidad Autónoma de Nuevo LeónMonterreyNL 64460México

Common gastrointestinal diseases such as radiation enteritis(RE),acute pancreatitis,inflammatory bowel diseases(IBD)and drug-induced hepatotoxicity share pathophysiological mechanisms at the molecular level,mostly involving the activation of many pathways of the immune response,ultimately leading to tissue *** oxidative stress,inflammatory cytokine release,inflammatory cell infiltration and activation and the up-regulation of inflammatory transcription factors participate in the pathophysiology of these complex *** varies in each specific disease,but at least in the cases of RE and IBD immunosuppressors are ***,full therapeutic responses are not always *** pathophysiology of ischemiareperfusion(IR)injury shares many of these *** and repetitive periods of ischemia in an organ or limb have been shown to protect against subsequent major IR injury in distant organs,a phenomenon called remote ischemic preconditioning(RIP).This procedure has been shown to protect the gut,pancreas and liver by modulating many of the same inflammatory *** RIP is safe and tolerable,and has shown to be effective in some recent clinical trials,I suggest that RIP could be used as a physiologicallyrelevant adjunct treatment for non-ischemic gastrointestinal inflammatory conditions.

关键词： Ischemia reperfusion Ischemic preconditioning Remote ischemic preconditioning Acute pancreatitis Radiation enteritis Inflammatory bowel diseases Hepatotoxicity Inflammation

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Contaminated open fracture and crush injury: a murine model

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Bone Research 2015年第1期3卷 31-39页

作者： Shawn R Gilbert Justin camara Richard camara Lynn Duffy Ken Waites Hyunki Kim Kurt Zinn Department of Surgery University of Alabama at Birmingham AL USA Loma Linda School of Medicine Loma LindaCAUSA Departments of Pathology University of Alabama at BirminghamAL USA Department of Radiology University of Alabama at BirminghamAL USA

Modern warfare has caused a large number of severe extremity injuries, many of which become infected. In more recent conflicts, a pattern of co-infection with Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus has emerged. We attempted to recreate this pattern in an animal model to evaluate the role of vascularity in contaminated open fractures. Historically, it has been observed that infected bones frequently appear hypovascular, but vascularity in association with bone infection has not been examined in animal models. Adult rats underwent femur fracture and muscle crush injury followed by stabilization and bacterial contamination with A. baumannii complex and methicillin-resistant Staphylococcus *** and perfusion were assessed by micro CT angiography and SPECT scanning, respectively, at 1, 2 and 4 weeks after injury. Quantitative bacterial cultures were also obtained. Multi-bacterial infections were successfully created, with methicillin-resistant S. aureus predominating. There was overall increase in blood flow to injured limbs that was markedly greater in bacteria-inoculated limbs. Vessel volume was greater in the infected group. Quadriceps atrophy was seen in both groups, but was greater in the infected group. In this animal model, infected open fractures had greater perfusion and vascularity than non-infected limbs.

关键词： MRSA Contaminated open fracture and crush injury a murine model

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Impact of land uses on water quality in Malaysia: a review

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Ecological Processes 2019年第1期8卷 128-137页

作者： Moriken camara Nor Rohaizah Jamil Ahmad Fikri Bin Abdullah Faculty of Environmental Studies Universiti Putra Malaysia UPM43400 SerdangSelangorMalaysia Department of Biological and Agricultural Engineering Faculty of EngineeringUniversiti Putra Malaysia(UPM)43400SerdangSelangorMalaysia.

Land use changes in urbanization,industrialization,and agricultural processes will continue to have negative impacts on water quality at all *** impact of land use changes on water quality is generally studied by analyzing the relationships between land use and water quality ***,the purpose of this research was to review and analyze the main relationships between land use and water quality,as well as to visualize the major sources and processes of water quality pollution in *** achieve our goal,we evaluated the significance of both land use and water quality attributes used in the past studies and correlated them to understand their relationship from another angle of *** results revealed that 87%of the reviewed studies indicated urban land use as a major source of water pollution,while 82%indicated agricultural land use,77%indicated forest land use,and 44%indicated other land ***,the results of correlation analysis showed that agricultural and forest-related activities more affected water quality through their significant positive correlation with physical and chemical indicators of water quality,while urban development activities had a greater impact on water quality through altering hydrological processes such as runoff and *** findings would provide decision-makers with useful information for managing water pollution processes rather than sources only.

关键词： Land use Water quality Malaysia

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Numerical analysis of flow and heat transfer behavior in fin-tube flat-plate solar collector

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Journal of Harbin Institute of Technology(New Series) 2007年第2期14卷 149-154页

作者： Namory camara 陆慧林 Dept. of Power Engineering Harbin Institute of Technology

Temperature distribution over the absorber plate of a parallel flow flat-plate solar collector is numerically analyzed. The governing differential equations with boundary conditions are solved numerically using fluent software. Effects of the inlet mass flux, inlet temperature and tube spacing on velocity and temperature distributions are discussed. Numerical results show that the distributions of velocity and temperature of fluid is unsymmetrical inside pipe.

关键词： sola energy simulation flat-plate

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The Contribution of the People’s Republic of China to Malian Conflict Resolution (2013-2017)

The Contribution of the People’s Republic of China to Malia...

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作者： Alassane camara 华中师范大学

学位级别：硕士

马里是一个土地辽阔、历史悠久、文化深厚的国家,马里人民多年来为祖国的和平与兴盛不懈努力。从古至今,在寻求社会、经济、文化在国内和国际发展的进程中,这个美丽的文化历史大国的发展之路上既铺满鲜花,也遍布荆棘。尽管如此,国家领... 详细信息

马里是一个土地辽阔、历史悠久、文化深厚的国家,马里人民多年来为祖国的和平与兴盛不懈努力。从古至今,在寻求社会、经济、文化在国内和国际发展的进程中,这个美丽的文化历史大国的发展之路上既铺满鲜花,也遍布荆棘。尽管如此,国家领导人的攻坚克难,加之国际上合作伙伴的多方支持,使得马里所面临的许多发展问题都迎刃而解。本文旨在研究自2012年起由恐怖分子和毒贩在马里北部引起的恐慌和危机。中国自建国以来一直是马里重要的合作伙伴之一,在解决这类冲突性问题时,中国从未袖手旁观。中国与马里的友好关系可以追溯至57年前莫迪博·凯塔总统时期与和毛泽东主席建立的友谊。本文将以中国帮助解决马里国内的冲突问题为切入点,考察两国之间友好的双边关系。中国已与其他国际合作伙伴一道,在联合国马里多层面综合稳定团的维和任务中,尤其是应对马里北部的危机方面做出了突出贡献;除此,中国还在马里境内的人员培训、医疗救助、后勤物资等方面做出了积极贡献,尤其在卫生防预、基础设施和工程建设等主要领域给予了马里人民无私援助。

关键词：非洲联盟马里中华人民共和国解决冲突

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Optimization of room-and-pillar dimensions using automated numerical models

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International Journal of Mining Science and Technology 2019年第5期29卷 797-801页

作者： Gian Franco Napa-García Tais Renata camara Vidal Félix Navarro Torres Mining Instituto Tecnológico ValeSanta LuziaMG 33040-900Brazil Exploration and Mineral Projects VALE S.A.Santa LuziaMG 33040-900Brazil

This paper presents an optimization methodology for the geometric configuration of a room–and–pillar mining project,considering safety and operational restrictions while maximizing ore *** underground manganese mine was chosen as a case study to investigate the capabilities of the presented methodology.A software package(OPTIMINE)was implemented to address the computational demand in an automated ***–dimensional finite difference analyses were performed in FLAC3D and used as implicit functions to consider safety in terms of the factor of safety and room *** obtained results showed that recovery could be increased from 44%to more than 80%in a safe manner.

关键词： Optimization Safety Room and pillar mining Ore recovery 3D numerical modeling

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Focus on the gut-brain axis: multiple sclerosis, the intestinal barrier and the microbiome

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World Journal of Gastroenterology 2018年第37期24卷 4217-4223页

作者： Carlos R camara-Lemarroy Luanne M Metz V Wee Yong Department of Clinical Neurosciences Cumming School of Medicine University of Calgary Hotchkiss Brain Institute Cumming School of Medicine University of Calgary

The brain-gut axis serves as the bidirectional connection between the gut microbiome, the intestinal barrier and the immune system that might be relevant for the pathophysiology of inflammatory demyelinating diseases. People with multiple sclerosis have been shown to have an altered microbiome, increased intestinal permeability and changes in bile acid metabolism. Experimental evidence suggests that these changes can lead to profound alterations of peripheral and central nervous system immune regulation. Besides being of pathophysiological interest, the brain-gut axis could also open new avenues of therapeutic targets. Modification of the microbiome, the use of probiotics, fecal microbiota transplantation, supplementation with bile acids and intestinal barrier enhancers are all promising candidates. Hopefully, pre-clinical studies and clinical trials will soon yield significant results.

关键词： Multiple sclerosis Microbiome Intestinal barrier Bile acids Gut-brain axis

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Performance of clinical signs and symptoms,rapid and reference laboratory diagnostic tests for diagnosis of human African trypanosomiasis by passive screening in Guinea:a prospective diagnostic accuracy study

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Infectious Diseases of Poverty 2023年第2期12卷 117-118页

作者： Oumou camara Mamadou camara Laura Cristina Falzon Hamidou Ilboudo Jacques Kaboré Charlie Franck Alfred Compaoré Eric Maurice Fèvre Philippe Büscher Bruno Bucheton Veerle Lejon Programme National de Lutte contre la Trypanosomiase Humaine Africaine Conakry Guinea International Livestock Research Institute Nairobi Kenya Institute of Infection Veterinary and Ecological Sciences University of Liverpool Liverpool UK Clinical Research Unit of Nanoro Institute for Health Science Research (IRSS) Ouagadougou Burkina Faso Vector-Borne Diseases and Biodiversity Unit International Research and Development Center on Livestock in Sub-Humid Areas (CIRDES) Bobo-Dioulasso Burkina Faso Unit of Research and Training in Life and Earth Sciences University of Nazi Boni Bobo-Dioulasso Burkina Faso Department of Biomedical Sciences Institute of Tropical Medicine Antwerp Belgium UMR Intertryp IRD-CIRAD French National Research Institute for Sustainable Development (IRD) University of Montpellier Montpellier France

Background Passive diagnosis of human African trypanosomiasis(HAT)at the health facility level is a major component of HAT control in *** examined which clinical signs and symptoms are associated with HAT,and assessed the performance of selected clinical presentations,of rapid diagnostic tests(RDT),and of reference laboratory tests on dried blood spots(DBS)for diagnosing HAT in *** The study took place in 14 health facilities in Guinea,where 2345 clinical suspects were tested with RDTs(HAT Sero-K-Set,rHAT Sero-Strip,and SD Bioline HAT).Seropositives underwent parasitological examination(reference test)to confirm HAT and their DBS were tested in indirect enzyme-linked immunoassay(ELISA)/Trypanosoma brucei gambiense,trypanolysis,Loopamp Trypanosoma brucei Detection kit(LAMP)and m18S quantitative PCR(qPCR).Multivariable regression analysis assessed association of clinical presentation with ***,specificity,positive and negative predictive values of key clinical presentations,of the RDTs and of the DBS tests for HAT diagnosis were *** The HAT prevalence,as confirmed parasitologically,was 2.0%(48/2345,95%CI:1.5–2.7%).Odds ratios(OR)for HAT were increased for participants with swollen lymph nodes(OR=96.7,95%CI:20.7–452.0),important weight loss(OR=20.4,95%CI:7.05–58.9),severe itching(OR=45.9,95%CI:7.3–288.7)or motor disorders(OR=4.5,95%CI:0.89–22.5).Presence of at least one of these clinical presentations was 75.6%(95%CI:73.8–77.4%)specific and 97.9%(95%CI:88.9–99.9%)sensitive for *** Sero-K-Set,rHAT Sero-Strip,and SD Bioline HAT were respectively 97.5%(95%CI:96.8–98.1%),99.4%(95%CI:99.0–99.7%)and 97.9%(95%CI:97.2–98.4%)specific,and 100%(95%CI:92.5–100.0%),59.6%(95%CI:44.3–73.3%)and 93.8%(95%CI:82.8–98.7%)sensitive for *** RDT’s positive and negative predictive values ranged from 45.2–66.7%and 99.2–100%*** DBS tests had specificities≥92.9%.While LAMP and m18S qPCR sensitivities were below 50%,trypanolysis and E

关键词： Human African trypanosomiasis Trypanosoma brucei gambiense Diagnosis Clinical Rapid diagnostic test Sensitivity Specificity Dried blood spot Trypanolysis

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