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Model-based framework for multi-axial real-time hybrid simulation testing

Earthquake Engineering and Engineering Vibration 2017年第4期16卷 671-691页

作者： Gaston A.Fermandois Billie F.Spencer,jr. Department of Civil and Environmental Engineering University of Illinois at Urbana-ChampaignUrbanaIL 61801USA

Real-time hybrid simulation is an efficient and cost-effective dynamic testing technique for performance evaluation of structural systems subjected to earthquake loading with rate-dependent behavior. A loading assembly with multiple actuators is required to impose realistic boundary conditions on physical specimens. However, such a testing system is expected to exhibit significant dynamic coupling of the actuators and suffer from time lags that are associated with the dynamics of the servo-hydraulic system, as well as control-structure interaction （CSI）. One approach to reducing experimental errors considers a multi-input, multi-output （MIMO） controller design, yielding accurate reference tracking and noise rejection. In this paper, a framework for multi-axial real-time hybrid simulation （maRTHS） testing is presented. The methodology employs a real-time feedback-feedforward controller for multiple actuators commanded in Cartesian coordinates. Kinematic transformations between actuator space and Cartesian space are derived for all six-degrees-of- freedom of the moving platform. Then, a frequency domain identification technique is used to develop an accurate MIMO transfer function of the system. Further, a Cartesian-domain model-based feedforward-feedback controller is implemented for time lag compensation and to increase the robustness of the reference tracking for given model uncertainty. The framework is implemented using the 1/5th-scale Load and Boundary Condition Box （LBCB） located at the University of Illinois at Urbana- Champaign. To demonstrate the efficacy of the proposed methodology, a single-story frame subjected to earthquake loading is tested. One of the columns in the fraane is represented physically in the laboratory as a cantilevered steel column. For real- time execution, the numerical substructure, kinematic transformations, and controllers are implemented on a digital signal processor. Results show excellent performance of the maRTHS framework when

关键词： real-time hybrid simulation multiple actuators dynamic coupling kinematic transformations model-basedcompensation

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Magnetic Cooling

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Journal of Rare Earths 2005年第4期23卷 I0001-I0002页

作者： Karl A. Gschneidner jr. Materials and Engineering Physics Ames Laboratory Department of Materials Science and Engineering Iowa State University Ames IA 50011-3020 USAMaterials and Engineering Physics Ames Laboratory Department of Materials Science and Engineering Iowa State University Ames IA 50011-3020 USA

The world has become highly dependent on reliable refrigeration technology. Without it, our food supply would be still seasonal and limited to locally produced nonperishable items; comfortable living conditions via climate control would be impossible; and certain medical advancements, e.g. MRI diagnostics, organ transplantation, organ and tissue cryo-storage, and cryo-surgery would be impossible. This technology remains essentially unchanged since it was invented 100 years ago.

关键词： Magnetic Cooling

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Optimal escape theory predicts escape behaviors beyond flight initiation distance:risk assessment and escape by striped plateau lizards Sceloporus virgatus

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Current Zoology 2009年第2期55卷 123-131页

作者： William E. COOPER jr. Department of Biology Indiana University Purdue University Fort Wayne

Escape theory predicts that flight initiation distance （FID = distance between predator and prey when escape begins） is longer when risk is greater and shorter when escape is more costly. A few tests suggest that escape theory applies to distance fled. Escape models have not addressed stochastic variables, such as probability of fleeing and of entering refuge, but their economic logic might be applicable. Experiments on several risk factors in the lizard Sceloporus virgatus confirmed all predictions for the above escape variables. FID was greater when approach was faster and more direct, for lizards on ground than on trees, for lizards rarely exposed to humans, for the second of two approaches, and when the predator turned toward lizards rather than away. Lizards fled further during rapid and second consecutive approaches. They were more likely to flee when approached directly, when a predator turned toward them, and during second approaches. They were more likely to enter refuge when approached rapidly. A novel finding is that perch height in trees was unrelated to FID because lizards escaped by moving out of sight, then moving up or down unpredictably. These findings add to a growing body of evidence supporting predictions of escape theory for FID and distance fled. They show that two probabilistic aspects of escape are predictable based on relative predation risk levels. Because individuals differ in boldness, the assessed optimal FID and threshold risks for fleeing and entering refuge are exceeded for an increasing proportion of individuals as risk increases

关键词： Approach distance Distance fled Flight initiation distance Predation risk Refuge entry Squamata

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Measuring magnetic declination with a compass, virtual globes and a global positioning system

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International Journal of Digital Earth 2009年第1期2卷 31-43页

作者： William P.O’Brien jr Physics Department Southwestern UniversityGeorgetownTexas78626USA

Earth’s magnetic declination was experimentally measured at 15 sites in western USA from Alaska to Texas;each site exhibited a large linear feature identifiable in virtual globe imagery(NASA’s World Wind or Google Earth).The difference between the geographic bearing of the linear feature measured directly on a virtual globe image and the magnetic bearing of the same linear feature measured on the ground with a compass defines the magnetic declination d for that *** all 15 sites,d values,determined by this differencing procedure,ranged from about 208 to 58 E and fell within 18(over half within 0.58)of expected *** positioning system(GPS)data recorded at most sites and plotted on virtual globe images aided in the identification of relevant *** straightforward method for determining magnetic declination using virtual globe software and a compass provides a contemporary geospatial field/laboratory activity that dramatically elucidates and contrasts features of magnetic and geographic coordinate systems for students in various disciplines involving geomagnetism,navigation,geography or spherical polar geometry.

关键词： Earth observation GPS magnetic declination geophysics

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Improving Energy and Power Efficiency Using NComputing and Approaches for Predicting Reliability of Complex Computing Systems

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International Journal of Automation and computing 2010年第2期7卷 153-159页

作者： Hoang Pham Hoang Pham jr. Department of Industrial and Systems Engineering Rutgers University Timothy Christian School

Opting to follow the computing-design philosophy that the best way to reduce power consumption and increase energy efficiency is to reduce waste, we propose an architecture with a very simple ready-implementation by using an NComputing device that can allow multi-users but only one computer is needed. This intuitively can save energy, space as well as cost. In this paper, we propose a simple and realistic NComputing architecture to study the energy and power-efficient consumption of desktop computer systems by using the NComputing device. We also propose new approaches to estimate the reliability of k-out-of-n systems based on the delta method. The k-out-of-n system consisting of n subsystems works if and only if at least k-of-the-n subsystems work. More specificly, we develop approaches to obtain the reliability estimation for the k-out-of-n systems which is composed of n independent and identically distributed subsystems where each subsystem （or energy-efficient usage application） can be assumed to follow a two-parameter exponential lifetime distribution function. The detailed derivations of reliability estimation of k-out-of-n systems based on the biased-corrected estimator, known as delta method, the uniformly minimum variance unbiased estimate （UMVUE） and maximum likelihood estimate （MLE） are discussed. An energy-management NComputing application is discussed to illustrate the reliability results in terms of the energy consumption usages of a computer system with qua（t-core, 8 GB of RAM, and a GeForce 9800GX-2 graphics card to perform various complex applications. The estimated reliability values of systems based on the UMVUE and the delta method differ only slightly. Often the UMVUE of reliability for a complex system is a lot more difficult to obtain, if not impossible. The delta method seems to be a simple and better approach to obtain the reliability estimation of complex systems. The results of this study also show that, in practice, the NComputing archite

关键词： Energy efficiency Ncomputing k-out-of-n system exponential distribution reliability estimation uniformly minimum variance unbiased estimate (UMVUE) maximum likelihood estimate (MLE).

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Restore or retreat? Saltwater intrusion and water management in coastal wetlands

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Ecosystem Health and Sustainability 2017年第1期3卷 38-55页

作者： Elliott White,jr. David Kaplan Engineering School of Sustainable Infrastructure and Environment University of FloridaGainesvilleFlorida 32611 USA

Coastal wetlands perform a unique set of physical,chemical,and biological functions,which provide billions of dollars of ecosystem services *** wetlands also face myriad environmental and anthropogenic pressures,which threaten their ecological condition and undermine their capacity to provide these *** wetlands have adapted to a dynamic range of natural disturbances over recent millennia,but face growing pressures from human population growth and coastal *** anthropogenic pressures are driving saltwater intrusion(SWI)in many coastal *** position of coastal wetlands at the terrestrial-marine interface also makes them vulnerable to increasing rates of sealevel rise and changing ***,anthropogenic and natural stressors to coastal wetlands can act synergistically to create negative,and sometimes catastrophic,consequences for both human and natural *** review focused on the drivers and impacts of SWI in coastal wetlands and has two goals:(1)to synthesize understanding of coastal wetland change driven by SWI and(2)to review approaches for improved water management to mitigate SWI in impacted *** we frame this review as a choice between restoration and retreat,we acknowledge that choices about coastal wetland management are context-specific and may be confounded by competing management *** this setting,the choice between restoration and retreat can be prioritized by identifying where the greatest return in ecosystem services can be achieved relative to restoration dollars *** conclude that restoration and proactive water management is feasible in many impacted systems.

关键词： climate change disturbance ecosystems restoration salinity saltwater intrusion watershed management wetlands

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Hepatitis B among Asian Americans:Prevalence, progress, and prospects for control

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World Journal of Gastroenterology 2015年第42期21卷 11924-11930页

作者： Moon S Chen jr Julie Dang Division of Hematology and Oncology Department of Internal Medicine University of California Davis School of Medicine Sacramento University of California Davis Comprehensive Cancer Center Sacramento National Cancer Institute-funded National Center for Reducing Asian American Cancer Health Disparities University of California Davis Comprehensive Cancer Center Sacramento

After tobacco use, chronic hepatitis B(CHB) viral infections are the most important cause of cancer globally in that 1 out of 3 individuals have been infected with the hepatitis B virus(HBV). Though infection rates are low(< 1%) in the United States, Asian Americans who comprise about 6% of the population experience about 60% of the CHB burden. This paper reviews the magnitude of hepatitis B(HBV) burden among Asian Americans and the progress being made to mitigate this burden, primarily through localized, communitybased efforts to increase screening and vaccination among Asian American children, adolescents, and adults. This review brings to light that despite the numerous community-based screening efforts, a vast majority of Asian Americans have not been screened and that vaccination efforts, particularly for adults, are sub-optimal. Greater efforts to integrate screenings by providers within existing healthcare systems are urged. Evidence-based strategies are offered to implement CDC's three major recommendations to control and prevent hepatitis B through targeted screening and enhanced vaccination efforts.

关键词： Hepatitis B Asian Americans Chronic hepatitis B Va

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Enteral nutrition in acute pancreatitis:A review of the current evidence

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World Journal of Gastroenterology 2014年第43期20卷 16123-16131页

作者： Attila Oláh Laszlo Romics jr Department of Surgery Petz Aladár Teaching HospitalH-9023 Gy?rHungary Department of Surgery Glasgow Victoria InfirmaryGlasgow G42 9TYUnited Kingdom

The use of enteral feeding as part of the management of acute pancreatitis dates back almost two *** review describes the indications for and limitations of enteral feeding for the treatment of acute pancreatitis using up-to-date evidence-based data.A systematic review was carried out to analyse current data on the use of enteral nutrition in the management of acute *** literature was analysed from the viewpoints of enteral vs parenteral feeding,early vs delayed enteral nutrition,nasogastric vs nasojejunal feeding,and early oral diet and immunonutrition,particularly glutamine and probiotic ***,current applicable guidelines and the effects of these guidelines on clinical practice are *** latest meta-analyses suggest that enteral nutrition significantly reduces the mortality rate of severe acute pancreatitis compared to parenteral *** maintain gut barrier function and prevent early bacterial translocation,enteral feeding should be commenced within the first 24 h of hospital ***,the safety of nasogastric feeding,which eases the administration of enteral nutrients in the clinical setting,is likely equal to nasojejunal ***,an earlylow-fat oral diet is potentially beneficial in patients with mild *** the initial encouraging results,the current evidence does not support the use of immunoenhanced nutrients or probiotics in patients with acute pancreatitis.

关键词： Acute pancreatitis Enteral nutrition Immunonutrition Probiotics

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Emerging complexity and new roles for the RIG-I-like receptors in innate antiviral immunity

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Virologica Sinica 2015年第3期30卷 163-173页

作者： John S.Errett Michael Gale jr. Center for Innate Immunity and Immune Disease Department of Immunology School of Medicine University of Washington

Innate immunity is critical for the control of virus infection and operates to restrict viral susceptibility and direct antiviral immunity for protection from acute or chronic viral-associated diseases including cancer. RIG-I like receptors(RLRs) are cytosolic RNA helicases that function as pathogen recognition receptors to detect RNA pathogen associated molecular patterns(PAMPs) of virus infection. The RLRs include RIG-I, MDA5, and LGP2. They function to recognize and bind to PAMP motifs within viral RNA in a process that directs the RLR to trigger downstream signaling cascades that induce innate immunity that controls viral replication and spread. Products of RLR signaling also serve to modulate the adaptive immune response to infection. Recent studies have additionally connected RLRs to signaling cascades that impart inflammatory and apoptotic responses to virus infection. Viral evasion of RLR signaling supports viral outgrowth and pathogenesis, including the onset of viral-associated cancer.

关键词： RIG-I MDA5 pattern recognition receptor pathogen associated molecular pattern innate immunity virus infection

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A Review on Cooperative Robotic Arms with Mobile or Drones Bases

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International Journal of Automation and computing 2021年第4期18卷 536-555页

作者： Larona Pitso Ramalepa Rodrigo S.Jamisola jr. Botswana International University of Science and Technology Palapye 10071Botswana

This review paper focuses on cooperative robotic arms with mobile or drone bases performing cooperative tasks. This is because cooperative robots are often used as risk-reduction tools to human life. For example, they are used to explore dangerous places such as minefields and disarm explosives. Drones can be used to perform tasks such as aerial photography, military and defense missions,agricultural surveys, etc. The bases of the cooperative robotic arms can be stationary, mobile(ground), or drones. Cooperative manipulators allow faster performance of assigned tasks because of the available "extra hand". Furthermore, a mobile base increases the reachable ground workspace of cooperative manipulators while a drone base drastically increases this workspace to include the aerial *** papers in this review are chosen to extensively cover a wide variety of cooperative manipulation tasks and industries that use *** cooperative manipulation, avoiding self-collision is one of the most important tasks to be performed. In addition, path planning and formation control can be challenging because of the increased number of components to be coordinated.

关键词： Cooperative arms mobile manipulator aerial manipulator mobile base drone base cooperative tasks

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