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Bifurcation Analysis of a Nonlinear Genetic Network Model with Time Delay
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作者 Anael Verdugo 《Journal of Applied Mathematics and Physics》 2023年第8期2252-2266,共15页
This paper presents a bifurcation study of a mRNA-protein network with negative feedback and time delay. The network is modeled as a coupled system of N ordinary differential equations (ODEs) and N delay differential ... This paper presents a bifurcation study of a mRNA-protein network with negative feedback and time delay. The network is modeled as a coupled system of N ordinary differential equations (ODEs) and N delay differential equations (DDEs). Linear analysis of the stable equilibria shows the existence of a critical time delay beyond which limit cycle oscillations are born in a Hopf bifurcation. The Poincaré-Lindstedt perturbation method is applied to the nonlinear system, resulting in closed form approximate expressions for the amplitude and frequency of oscillation. We confirm our perturbation analysis results by numerically simulating the full 2N-dimensional nonlinear system for N = 2, 7, 15, and 30. Our results show that for small perturbations the equilibrium undergoes a supercritical Hopf and the system exhibits stable periodic solutions. Furthermore, our closed form numerical expressions exhibit the importance of the network’s negative feedback and nonlinear effects. 展开更多
关键词 Bifurcation Analysis HOPF Delay Differential Equations
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近十年中国地质灾害时空发育规律分析 被引量:21
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作者 薛凯喜 胡艳香 +3 位作者 邹玉亮 Binod Tiwari 魏永起 顾连胜 《中国地质灾害与防治学报》 CSCD 2016年第3期90-97,共8页
本文对中国国土资源部发布的历年《全国地质灾害通报》进行了全面梳理,依托2005-2014年各类地质灾害记录数据详尽分析了研究区域内地质灾害的时空发育规律。六种灾害类别中山体滑坡和崩塌灾害的发育显著性最为明显,泥石流次之,且具有群... 本文对中国国土资源部发布的历年《全国地质灾害通报》进行了全面梳理,依托2005-2014年各类地质灾害记录数据详尽分析了研究区域内地质灾害的时空发育规律。六种灾害类别中山体滑坡和崩塌灾害的发育显著性最为明显,泥石流次之,且具有群发性和伴发性特征;地质灾害发育的区域差异性非常显著,文中分别给出了地质灾害高度发育与因灾损失最为严重的省级区域,并分析了各省级区域因灾损失程度和灾害发育总量的关系,但其相关性并不明显;除四川省外,重大地质灾害多发的省份并非灾害总量居高的省份,重大地质灾害的的集中发育时间与极端降雨频发月份基本相符,且统计显示其诱因主要为强降雨;近年来中国地质灾害成功避让起数、灾害避让率和避免死亡人数等预警预报成效逐步提高,但避免直接经济损失的规律性不强,一定程度上突显出遭遇地质灾害时对房屋及基础设施等不动产的保护能力尚显不足。本文的相关结论源自统计数据的直观分析,可为地质灾害防治及预警预报工作提供客观的咨询依据。 展开更多
关键词 地质灾害 灾情分级 损失程度 预警预报
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基于模糊神经网络的电力调度自动化设备健康评估 被引量:16
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作者 李鹏 李丹 +1 位作者 李喜旺 高宇 《计算机系统应用》 2019年第2期207-212,共6页
针对电力调度自动化设备健康评估过程中存在的评估方式简单、评估方式可解释性弱以及评估效果不精确的问题,本文提出了一种基于模糊神经网络的电力自动化设备健康评估模型.用模糊理论进行分析,用模糊集合描述评价指标,用数据指标的隶属... 针对电力调度自动化设备健康评估过程中存在的评估方式简单、评估方式可解释性弱以及评估效果不精确的问题,本文提出了一种基于模糊神经网络的电力自动化设备健康评估模型.用模糊理论进行分析,用模糊集合描述评价指标,用数据指标的隶属度描述设备运行情况,结合神经网络的自适应功能,针对个体设备提供更加准确的、更具个性化的健康评估. 展开更多
关键词 模糊神经网络 自动化设备 健康评估
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Analyzing sustainability of construction equipment in the state of California 被引量:1
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作者 Hakob AVETISYAN Miroslaw SKIBNIEWSKI Mohammad MOZAFFARPOUR 《Frontiers of Engineering Management》 2017年第2期138-145,共8页
Construction equipment encompasses highly polluting machines adversely affecting the environment.Management tools are necessary for sustainability assessment of construction equipment fleets to allow contractors to re... Construction equipment encompasses highly polluting machines adversely affecting the environment.Management tools are necessary for sustainability assessment of construction equipment fleets to allow contractors to reduce their emissions and comply with local or federal regulations. In addition to management tools, there is a need for a metrics that will allow companies to accurately assess the sustainability of their construction equipment fleets. The State of California USA is adopting innovative approaches to reduce adverse impact of humans on the environment. Once successfully implemented, the chances are that such practices attract other states to adopt similar approaches. This paper presents an evaluation of construction equipment fleets and data analysis. When measured and recorded, such results can be used along with decisionsupport tools for selection and utilization of construction equipment. The metrics for construction equipment evaluation as well as the tool for sustainable decisionmaking are developed based on readily available data from manufacturers or maintenance shops without a need for additional effort by contractors or government agencies for their adoption. The metrics developed and the decision support tool incorporate logical strategies of supply chain management for optimal selection of construction equipment for construction site while taking into account the availability, cost, and mobilization related constraints. The metrics and the model can benefit both the government agencies responsible for inspection of fleets and owners of construction companies in their decision-making processes related to environmental sustainability. 展开更多
关键词 Construction equipment greenhouse gas emissions sustainability index sustainable construction
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God Is a Porcupine—Brain, Consciousness and Spacetime Physics
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作者 Walter J. Christensen Jr. 《Journal of Modern Physics》 2017年第8期1294-1318,共25页
Whereas the human body requires a vast numbers of atoms to maintain its intricate anatomical functions, we assert that the human brain requires “something extra” to carry out its higher mental and emotional function... Whereas the human body requires a vast numbers of atoms to maintain its intricate anatomical functions, we assert that the human brain requires “something extra” to carry out its higher mental and emotional functions. Recently, neuroscientists are beginning to suspect brain cells are not fast enough, or intricate enough, to correlate complex spatiotemporal information into cognitive understanding. They conclude that spacetime fields may be necessary to assist the brain during neurological processing—in much the same way magnetic and electric fields are essential for the propagation of light. This “something extra,” we argue, is spacetime itself—where structures in the brain, called facilitators (somewhat like Descartes pineal gland), have evolved biologically in such a way, so as to be able to store and retrieve spacetime quanta for the formation and generation of consciousness and memory. In this way, cognition is not a thing complete. Rather it is emergent, and accumulates as discretized spacetime quanta in the brain so rapidly, we perceive our own awareness to be continuous, events spontaneous. In this paper, we consider spacetime to be a field (like all quantum fields), which can be excited into quanta particles called gravitons. We then apply this quanta excitation to help explain the brain’s cognitive processes. If the brain has indeed evolved to interact with discretized spacetime, then with the advent of improved functional imaging equipment, we might be able to map detailed correlations between neural processes, conscious experience and spacetime. In so doing, it might be possible to learn more about the fundamental workings of spacetime itself. 展开更多
关键词 Neuroscience CONSCIOUSNESS Memory BRAIN Communication SPACETIME SPACETIME Quanta GRAVITONS Time Quanta General Relativity Relativized Quantum PHYSICS (RQP)
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Mach’s Principle, Action at a Distance and Cosmology
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作者 H. Fearn 《Journal of Modern Physics》 2015年第3期260-272,共13页
Hoyle and Narlikar (HN) in the 1960’s [1] 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F005200650066003400310031003900330036003000340034000000 -[3] 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E00... Hoyle and Narlikar (HN) in the 1960’s [1] 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F005200650066003400310031003900330036003000340034000000 -[3] 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F005200650066003400310031003900330036003000340037000000 developed a theory of gravitation which was completely Machian and used both retarded and advanced waves to communicate gravitational influence between particles. The advanced waves, which travel backward in time, are difficult to visualize and although they are mathematically allowed by relativistic wave equations, they never really caught on. The HN theory reduced to Einstein’s theory of gravity in the smooth fluid approximation and a transformation into the rest frame of the fluid. Hawking [4] 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F005200650066003400310031003900330036003000350030000000 in 1965 pointed out a possible flaw in the theory. This involved integrating out into the distant future to account for all the advanced waves which might influence the mass of a particle here and now. Hawking used infinity as his upper time limit and showed the integral was divergent. We point out that since the universe is known to be expanding, and accelerating, the upper limit in the advanced wave time integral should not be infinite but is bounded by the Cosmic Event Horizon. This event horizon He represents a barrier between future events that can be observed and those which cannot. We show that the advanced wave integral is finite when He/C, is used as the upper limit of the advanced wave integral. Hawking’s objection is no longer valid and the HN theory becomes a working theory once again. 展开更多
关键词 Mach’s PRINCIPLE Action at a Distance Advanced WAVES Hoyle-Narlikar Theory Accelerating UNIVERSE EVENT HORIZON
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影响新托福阅读部分分数的因素
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作者 周文茜 《湖南人文科技学院学报》 2017年第6期68-71,113,共5页
第二语言的阅读板块的教学方法很大程度上受到了各种不同第二语言习得理论框架的影响,并且以此引发了二语教学法在此领域的根本性转变。影响新托福阅读分数的因素有:考生的英语语言能力,批判性思维能力,阅读技巧能力,学科背景知识/可被... 第二语言的阅读板块的教学方法很大程度上受到了各种不同第二语言习得理论框架的影响,并且以此引发了二语教学法在此领域的根本性转变。影响新托福阅读分数的因素有:考生的英语语言能力,批判性思维能力,阅读技巧能力,学科背景知识/可被激活的内容图式,考生对于机考的操作熟练度。 展开更多
关键词 新托福阅读部分 语言能力 批判性思维能力 阅读理解技巧 学科背景知识 内容图式
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Theory of a Mach Effect Thruster I
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作者 Heidi Fearn Adam Zachar +1 位作者 Keith Wanser James Woodward 《Journal of Modern Physics》 2015年第11期1510-1525,共16页
The Mach Effect Thruster (MET) is a propellant—less space drive which uses Mach’s principle to produce thrust in an accelerating material which is undergoing mass—energy fluctuations, [1]-[3]. Mach’s principle is ... The Mach Effect Thruster (MET) is a propellant—less space drive which uses Mach’s principle to produce thrust in an accelerating material which is undergoing mass—energy fluctuations, [1]-[3]. Mach’s principle is a statement that the inertia of a body is the result of the gravitational interaction of the body with the rest of the mass-energy in the universe. The MET device uses electric power of 100 - 200 Watts to operate. The thrust produced by these devices, at the present time, are small on the order of a few micro-Newtons. We give a physical description of the MET device and apparatus for measuring thrusts. Next we explain the basic theory behind the device which involves gravitation and advanced waves to incorporate instantaneous action at a distance. The advanced wave concept is a means to conserve momentum of the system with the universe. There is no momentun violation in this theory. We briefly review absorber theory by summarizing Dirac, Wheeler-Feynman and Hoyle-Narlikar (HN). We show how Woodward’s mass fluctuation formula can be derived from first principles using the HN-theory which is a fully Machian version of Einstein’s relativity. HN-theory reduces to Einstein’s field equations in the limit of smooth fluid distribution of matter and a simple coordinate transformation. 展开更多
关键词 MACH EFFECT Drive Transient Mass Fluctuations Weak Field Limit GRAVITATION Modified (PPN) Parameterized Post NEWTONIAN Approximation Linearized EINSTEIN Equations Gravitoelectromagnetism
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Theory of a Mach Effect Thruster II
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作者 Heidi Fearn Nolan van Rossum +1 位作者 Keith Wanser James F. Woodward 《Journal of Modern Physics》 2015年第13期1868-1880,共13页
According to Einstein, General Relativity contains the essence of Mach’s ideas. Mach’s principle can be summarized by stating that the inertia of a body is determined by the rest of the mass-energy content of the un... According to Einstein, General Relativity contains the essence of Mach’s ideas. Mach’s principle can be summarized by stating that the inertia of a body is determined by the rest of the mass-energy content of the universe. Inertia here arises from mass-energy there. The latter, was a statement made by John Wheeler in his 1995 book, Gravitation and Inertia, coauthored by Ciufolini. Einstein believed that to be fully Machian, gravity would need a radiative component, an action-at-a-distance character, so that gravitational influences on a body from far away could be felt immediately. In 1960’s, Hoyle and Narlikar (HN) developed such a theory which was a gravitational version of the Absorber theory derived by Wheeler-Feynman for classical electrodynamics and later expanded upon by Davies and Narlikar for quantum electrodynamics. The HN-field equation has the same type of mass fluctuation terms as in the Woodward Mach effect thruster theory. The force equation, used to predict the thrust in our device, can be derived from the mass fluctuation. We outline a new method for deriving the force equation. We present new experimental tests of the thruster to show that the thrust seen in our device is not due to either heating or Dean Drive effects. Successful replications have been performed by groups in Austria and Canada, but their work is still pending in the peer review literature. 展开更多
关键词 MACH EFFECT Drive Transient Mass FLUCTUATIONS Mach’s Principle Action at a Distance Advanced WAVES Event HORIZON
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On Lorentz Transformations and the Theory of Relativity
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作者 Fleur T. Tehrani 《Journal of Modern Physics》 CAS 2022年第11期1341-1347,共7页
In the course of a research study on Lorentz transformations and the theory of relativity, the fundamentals of the relativistic concepts of space and time, the relations of those concepts to Lorentz transformations, a... In the course of a research study on Lorentz transformations and the theory of relativity, the fundamentals of the relativistic concepts of space and time, the relations of those concepts to Lorentz transformations, and equivalence of mass and energy were studied. Many important references on the said subjects were reviewed. This paper draws attention to some critical questions that have risen in the course of that research study on the concepts of expansion of time and unbounded increase of a particle’s mass with velocity. 展开更多
关键词 Lorentz Transformations Relativity Theory MASS ENERGY
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Consumer Risk Perceptions in Mobile Health Services Adoption: Do They Matter?
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作者 Mihail Cocosila Ofir Turel 《E-Health Telecommunication Systems and Networks》 2022年第2期67-84,共18页
The purpose of this study is to investigate empirically the role of consumer perceived risks in the adoption of mobile health services. A theoretical model including the perceived risk associated with the activity tar... The purpose of this study is to investigate empirically the role of consumer perceived risks in the adoption of mobile health services. A theoretical model including the perceived risk associated with the activity targeted by a mobile health service and the perceived risk associated with the mobile service itself was developed and tested empirically in the context of an application supporting smoking cessation. The model was validated in a cross-sectional experiment conducted with 422 consumers in the UK and Canada. Findings show that while risk triggered by the nature of a health promotion activity is a strong driver of the adoption of the supporting mobile health service, risk related to the actual application targeting that activity is a comparatively weaker obstacle. The two contrasting risk perspectives are highly significant as they together explain over 31% of the variance in consumer intention to use the mobile health service, independently from other adoption factors. Overall, this study demonstrates that consumer risk perceptions alone are a multifaceted and meaningful component in mobile health services adoption, and that this element should not be overlooked in more complex research models. 展开更多
关键词 Mobile Service Information and Communication Technology Consumer Adoption Perceived Risk Healthcare
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Franck-Condon factors and γ-Centroids for the A^1 ∑^+ u-X^1∑^+ 9 Band System of ^107,109Ag2: Comparison of the Observed and Calculated Absorption Band Strengths
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作者 A.Antic-Jovanovic M.Kuzmanovic +2 位作者 V.Bojovic Murtadha A.Khakoo Russ R.Laher 《Chinese Physics Letters》 SCIE CAS CSCD 2007年第9期2566-2568,共3页
Franck-Condon factors and r-centrolds for the, A^1 ∑^+ u-X^1∑^+ 9 band system of ^107,109Ag2 are computed using Morse and Rydberg-Klein-Rees potentials for both lower and upper electronic states. The differences ... Franck-Condon factors and r-centrolds for the, A^1 ∑^+ u-X^1∑^+ 9 band system of ^107,109Ag2 are computed using Morse and Rydberg-Klein-Rees potentials for both lower and upper electronic states. The differences between the two sets of results are typically in the third decimal place for transitions involving vibrational levels with ν' and ν" up to about 15. Somewhat larger deviations appear for higher vibrational levels, but both sets of results follow the same pattern, which is to match well with the relative absorption band strength distribution in our experimental spectrum. The relative absorption band strengths are calculated by assuming that the electronic transition moment has only a weak dependence on the internuclear distance r. Good agreement between our measured and calculated absorption band strength ratios is found, which provides an excellent test of the calculated Franck- Condon factors and relative absorption band strengths. The r-centrold value for the (ν' = 0, ν" = 0) band is found to be approximately equal to the average value of r' and r''e , indicating that the potentials of both states are not significantly aaharmonic around their minimum regions. 展开更多
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Origin and evolution of palaeokarst within the Lower Ordovician (Ibexian) Goodwin Formation (Pogonip Group)
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作者 Robert J. Kervin Adam D. Woods 《Journal of Palaeogeography》 SCIE 2012年第1期57-69,共13页
Palaeokarst within the Lower to Middle Ordovician Goodwin Formation, Pogonip Group (upper Ibexian-lower Whiterockian) was examined in detail at Meiklejohn Peak, Nevada USA in order to determine its origin, evolution, ... Palaeokarst within the Lower to Middle Ordovician Goodwin Formation, Pogonip Group (upper Ibexian-lower Whiterockian) was examined in detail at Meiklejohn Peak, Nevada USA in order to determine its origin, evolution, and relationship to sea level change. Detailed outcrop and petrographic examination of dolostone breccias and host rock reveals that palaeokarst was formed and affected by two distinct cycles of sea level change. A relative transgression resulted in deposition of lagoonal, ooid shoal, and shallow subtidal facies as sea level rose. Exposure of the carbonate platform led to the formation of multiple phreatic caves below the water table, as well as the development of numerous vadose conduits from the downward percolation of meteoric waters. Vadose water flow through early cave-wall and cave-roof collapse breccias resulted in rounding of smaller breccias clasts via physical transport and corrosion, while subsidence of subsurface karst led to the formation of a palaeodoline at the exposure surface. A second relative transgression deposited lagoonal sediments over the older karst; subsequent re-exposure of the carbonate platform resulted in the development of small breccia pockets as well as grikes within the youngest lagoonal sediments, and may have led to further corrosion of the older, deeper subsurface karst. The distal location of the study area within the carbonate platform suggests karst formation was the result of a substantial drop in relative sea level; the presence of multiple generations of palaeokarst imply that at least two higher-frequency cycles of sea-level change overprint the larger regression. 展开更多
关键词 PALAEOKARST ORDOVICIAN CARBONATES BRECCIA Great Basin
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Relationship Between Metabolic Fitness and Performance in Police Occupational Tasks
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作者 Elisa F.D.Canetti J.Jay Dawes +5 位作者 Phoebe H.Drysdale Robert Lockie Charlie Kornhauser Ryan Holmes Ben Schram Robin M.Orr 《Journal of Science in Sport and Exercise》 2021年第2期179-185,共7页
Purpose To determine the relationship between metabolic fitness test scores and performance in police occupational tasks.Methods Retrospective data from 106 law enforcement officers who completed two metabolic fitness... Purpose To determine the relationship between metabolic fitness test scores and performance in police occupational tasks.Methods Retrospective data from 106 law enforcement officers who completed two metabolic fitness assessments[anaerobic:a 20-m (10-m and 20-m splits) sprint,aerobic:20 m Multi-Stage Fitness Test (20 m-MSFT)]and three routine occupational tasks[1.22 m Fence jump (FJ),8.5 m Victim Drag (VD with 102.3 kg) and "Get-up" (GU)]were collected.A Person's cor-relation coefficient and a standard multiple regression were used to assess the relationship between and predictive ability of,respectively,the fitness tests scores and performance on occupational tasks.Results There was a significant positive correlation between the 10-m sprint scores and FJ (r=0.524,P<0.001),VD(r =0.528,P < 0.001) and GU (r=0.486,P < 0.001).Similarly,the 20-m sprint scores were significantly and moderately correlated with FJ (r=0.573,P < 0.001),VD (r=0.603,P < 0.001) and GU (r=0.533,P < 0.001).These anaerobic tests' scores predicted approximately 40% of the performance in the occupational tasks analysed.The MSFT fitness assessment had a small,albeit significant negative correlation with the three tasks:FJ (r=-0.360,P< 0.001),VD (r=-0.266,P=0.012)and GU (r=-0.375,P< 0.001).Conclusion High levels of metabolic fitness correlated with faster performance in police officer occupational tasks,particu-larly ones of an anaerobic nature (i.e.the maximal sprint tests).In addition to typical aerobic fitness conditioning,anaerobic fitness conditioning could be vital for optimal performance in physically demanding tasks required of police officer. 展开更多
关键词 POLICE Occupational health Physical fitness Work performance REHABILITATION
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