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Littérature scientifique sur le sujet « Express highways Mathematical models »

Auteur : Grafiati

Publié le 4 juin 2021

Mis à jour le 19 février 2022

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Articles de revues sur le sujet "Express highways Mathematical models"

Kassu, Aschalew, et Michael Anderson. « Analysis of Nonsevere Crashes on Two- and Four-Lane Urban and Rural Highways : Effects of Wet Pavement Surface Condition ». Journal of Advanced Transportation 2018 (2 août 2018) : 1–10. http://dx.doi.org/10.1155/2018/2871451.

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This study examines the effects of wet pavement surface conditions on the likelihood of occurrences of nonsevere crashes in two- and four-lane urban and rural highways in Alabama. Initially, sixteen major highways traversing across the geographic locations of the state were identified. Among these highways, the homogenous routes with equal mean values, variances, and similar distributions of the crash data were identified and combined to form crash datasets occurring on dry and wet pavements separately. The analysis began with thirteen explanatory variables covering engineering, environmental, and traffic conditions. The principal terms were statistically identified and used in a mathematical crash frequency models developed using Poisson and negative binomial regression models. The results show that the key factors influencing nonsevere crashes on wet pavement surfaces are mainly segment length, traffic volume, and posted speed limits.

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Burinskienė, Marija, Denis Kapski, Valery Kasyanik, Anton Pashkevich, Aleksandra Volynets et Oleg Kaptsevich. « Estimating Parameters for Traffic Flow Using Navigation Data on Vehicles ». Baltic Journal of Road and Bridge Engineering 15, n^o 4 (28 septembre 2020) : 1–21. http://dx.doi.org/10.7250/bjrbe.2020-15.492.

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The article describes the method for estimating transport flow parameters using the two-fluid Herman-Prigogine mathematical model developed considering the proposed method of estimating parameters for the system based on the passive processing of navigation data on the movement of vehicles. The efficiency of the suggested algorithms and mathematical models for estimating road traffic flow parameters and the system as a whole was confirmed performing tests using a set of tracks on the main highways of Belarus.

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Sukharev, R. Yu. « Mathematical models of wheel turning processes road construction vehicles ». Nauchno-tekhnicheskiy vestnik Bryanskogo gosudarstvennogo universiteta 7, n^o 3 (25 septembre 2021) : 259–69. http://dx.doi.org/10.22281/2413-9920-2021-07-03-259-269.

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The construction of highways is a complex, multi-stage process. Most of the construction works are carried out according to the projects of structures and quite high requirements are imposed on the quality of execution. The fulfillment of these requirements is associated with great difficulties in view of the limited accuracy of the road construction machine itself, the lack of on-board control systems and the limited capabilities of the human operator, who is unable to determine the required exact parameters of the structure being built «by eye». To meet the requirements, three-dimensional control systems are used, which allow determining 3 coordinates of the working order of the machine – the vertical coordinate and the location of the machine on the construction site. At the same time, the digital project of the constructed structure should be the setter in such a system. The system determines the current position and compares it with the project. On the basis of this information, a control effect on the operating organ of the machine is formed. The course of movement and the speed of the machine when using such systems are determined by the machine operator. Further development of these systems should be four-dimensional systems – in which all control actions are assigned to the control system, starting from calculating the trajectory of the machine, choosing the speed, determining the required number of passes and ending with controlling the position of the working body of the machine at each moment of time. For the functioning of these systems, adequate mathematical models of the turning processes of road construction machines with different steering options are necessary.

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Kapski, Denis, Valery Kasyanik, Oleksii Lobashov, Aleksandra Volynets, Oleg Kaptsevich et Andrii Galkin. « Estimating the Parameters of Traffic Flows on the Basis of Processing of Localization Data on the Movement of Vehicles ». Communications - Scientific letters of the University of Zilina 21, n^o 2 (24 mai 2019) : 89–99. http://dx.doi.org/10.26552/com.c.2019.2.89-99.

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The article describes the method of estimating the parameters of transport flows using the two-fluid mathematical model of Herman-Prigogine and developed and based on the proposed method of estimating the parameters of the system on the basis of passive processing of navigation data on the movement of vehicles. The efficiency of the proposed algorithms, mathematical models for estimating the parameters of road traffic flow and system as a whole was confirmed during its testing using a set of tracks on the main highways of Commonwealth of Independent States.

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Akalili, Imania Aufi. « PROFIL KEMAMPUAN KOMUNIKASI MATEMATIS SISWA DALAM MENYELESAIKAN MASALAH GEOMETRI DITINJAU DARI LEVEL VAN HIELE ». KadikmA 11, n^o 3 (5 février 2021) : 40. http://dx.doi.org/10.19184/kdma.v11i3.22580.

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Mathematical communication skills are needed to express ideas, messages, and ideas through written or oral. The research subjects were five students of class XII SMAN Ambulu who were categorized in van Hiele level. The results of the data analysis obtained were students with informal deduction had the ability to express mathematical ideas through written or oral, the ability to understand mathematical ideas both orally and in writing and the ability to use terms and notations to present data, and had the ability to present ideas. mathematics in solving or describing models of mathematical problems. Students of analysis have the ability to express mathematical ideas through oral, the ability to understand and evaluate mathematical ideas both orally and in writing, and are able to use mathematical terms and notations in presenting mathematical ideas. Visualization students are able to explain how to describe geometric transformations orally and are able to use notations and terms in presenting data.

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Kapskiy, D. V., V. V. Kasyanik, A. V. Evtuh et O. F. Kaptsevich. « EVALUATION OF TRANSPORT FLOW EFFICIENCY ON THE BASIS OF TRAFFIC MOVEMENT DATA ». Science & ; Technique 16, n^o 5 (5 octobre 2017) : 444–54. http://dx.doi.org/10.21122/2227-1031-2017-16-5-444-454.

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The paper considers a method for evaluation of transport flow parameters and determine an efficiency of variants concerning organization of traffic movement and provision of qualitative transportation. A method for evaluation of main traffic flow parameters while using a two-fluid mathematical model of Herman – Prigogine has been developed and it is based on passive processing of navigation data for road transport facilities on highways and urban road and street networks. The main advantages and novelty of the method (in contrast with the traditional usage of a mathematical model of Her- man – Prigogine on the basis of active processing of navigation data) are the following: a passive treatment of GPS-tracks and support of their formats that make it possible significantly improve quality and adequacy of the model results; cloud com-puting (usage of cloud storage for storing large bulk of data); presence of client mobile application for Android operating system which is used for data collection in addition to operation with already collected navigation data from navigation and information center and other sources; application for calculation and processing of modern web technologies; scalability and configurability of the system. Efficiency of the proposed algorithms, mathematical models for evaluation of transport flow parameters and system as a whole have been proved in the process of their approbation while using a set of tracks on main highways of Belarus

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Zayyadi, Moh, et Kuratul Aini Saleh. « WRITTEN MATHEMATICAL COMMUNICATION SKILLS ON OPEN-ENDED PROBLEMS : IS IT DIFFERENT BASED ON THE LEVEL OF MATHEMATICS ABILITY ? » MaPan 8, n^o 2 (15 décembre 2020) : 179–204. http://dx.doi.org/10.24252/mapan.2020v8n2a2.

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This study aims to describe students' written mathematical communication skills in open-ended problems based on their mathematical abilities. This research was conducted at grade VII-A of SMPN 1 Pamekasan. This research uses descriptive qualitative research. The instruments used were the Mathematical Ability Test (MAT), Written Mathematical Communication Skills Test (WMCST) on open-ended problems, and Interview Guidelines. The results showed that subjects with high and moderate mathematical ability were able to meet three indicators of written mathematical communication skills, namely being able to express mathematical ideas through writing, demonstrate and convey visually; able to understand, interpret and evaluate mathematical ideas in writing, as well as in other visual forms; and able to use mathematical notations in the structure to write down ideas and relationships with situation models in writing. Meanwhile, subjects with low mathematics ability can fulfill 2 out of 3 indicators of written mathematical communication skills, namely being able to express mathematical ideas through writing, demonstrate and convey visually; unable to understand, interpret and evaluate mathematical ideas in writing or other visual forms; and able to use mathematical notations in the structure to write ideas and relationships with situation models.

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Mullakkal-Babu, Freddy Antony, Meng Wang, Haneen Farah, Bart van Arem et Riender Happee. « Comparative Assessment of Safety Indicators for Vehicle Trajectories on Highways ». Transportation Research Record : Journal of the Transportation Research Board 2659, n^o 1 (janvier 2017) : 127–36. http://dx.doi.org/10.3141/2659-14.

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Safety measurement and its analysis have been challenging and well-researched topics in transportation. Conventionally, surrogate safety measures have been used as safety indicators in simulation models for safety assessment, in control formulations for driver assistance systems, and in data analysis of naturalistic driving studies. However, surrogate indicators give partial insights on traffic safety; that is, these indicators only indicate a predetermined set of possible precrash situations for an interacting vehicle pair. Recently, a safety indicator called the “driving safety field,” based on field theory, was proposed for two-dimensional vehicle interactions. However, the objectivity of its functional form and its validity have yet to be tested. A qualitative and quantitative comparison of different safety indicators was provided as a risk measure to demarcate their mathematical properties and evaluate their usefulness in quantifying trajectory risk. Five relevant safety indicators were compared: inverse time to collision, postencroachment time, potential indicator of collision with urgent decceleration, warning index, and safety field force. Their formulations were mathematically analyzed to yield qualitative insights and their values over simulated vehicle trajectories were evaluated to yield quantitative insights. The results acknowledge the limitations and demarcate the functional utilities of the selected safety indicators.

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Liu, Tin Tin, Guo Jin Chen, You Ping Gong et Zhi Hua Li. « Research on Unified Expression Method of Multi-Domain Constraint Models ». Advanced Materials Research 971-973 (juin 2014) : 938–41. http://dx.doi.org/10.4028/www.scientific.net/amr.971-973.938.

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This paper is mainly discussed the establishment of the unified constraint expression of simulation optimization model. Express all kinds of element constraints with unified physical mathematical mapping mechanism, uniform the model representation of product components in each domain and establish the unified expression model, in order to facilitate the follow-up simulation solution of multi-domain constraint system.

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Montejo-Gámez, Jesús, Elvira Fernández-Ahumada et Natividad Adamuz-Povedano. « A Tool for the Analysis and Characterization of School Mathematical Models ». Mathematics 9, n^o 13 (3 juillet 2021) : 1569. http://dx.doi.org/10.3390/math9131569.

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This paper shows a tool for the analysis of written productions that allows for the characterization of the mathematical models that students develop when solving modeling tasks. For this purpose, different conceptualizations of mathematical models in education are discussed, paying special attention to the evidence that characterizes a school model. The discussion leads to the consideration of three components, which constitute the main categories of the proposed tool: the real system to be modeled, its mathematization and the representations used to express both. These categories and the corresponding analysis procedure are explained and illustrated through two working examples, which expose the value of the tool in establishing the foci of analysis when investigating school models, and thus, suggest modeling skills. The connection of this tool with other approaches to educational research on mathematical modeling is also discussed.

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Thèses sur le sujet "Express highways Mathematical models"

Lierkamp, Darren. « Simulating the effects of following distance on a high-flow freeway ». Full text available online (restricted access), 2003. http://images.lib.monash.edu.au/ts/theses/Lierkamp.pdf.

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"CP830 Research Project and Thesis 2". Includes bibliographical references (p. 80-93) Electronic reproduction.[S.l. :s.n.],2003.Electronic data.Mode of access: World Wide Web.System requirements: Adobe Acrobat reader software for PDF files.Access restricted to institutions with a subscription.

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BONKAT, BARNABAS NANPAK. « ANALYTICAL PROCEDURE FOR EVALUATING ROADWAY UPGRADING STRATEGY FOR LOW-VOLUME HIGHWAYS ». Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/187926.

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The purpose of this research was to develop a simplified analytical procedure for determining the optimal timing for upgrading low-volume roads in developing countries. Most roadway upgradings from gravel to surface treated and to asphaltic concrete are carried out when total transport cost on a road becomes high as a result of high traffic and the consequent rapid deterioration of the roadway. Adequate timing of upgrading strategies ensures effective use of resources and lower total transport cost. This study examined existing systems, models, and approaches for estimating total transport cost components. An analytical procedure was then developed using a decision-tree concept to delineate all possible upgrading strategies within a plan period. The decision-tree concept depicts all the possible upgrading strategies within a plan period with decisions on roadway upgrading made at certain decision intervals. The total transport cost of the upgrading strategies is evaluated to establish the optimal strategies and traffic warrants for improving a roadway surface. A computer program PVMNT was written to facilitate the computation of the total transport cost. A case study was presented to demonstrate the application of the analytical procedure. The case study revealed interesting results on the changes of optimal upgrading strategies with changes in base traffic volume and growth rate. However, general conclusions could not be drawn based on the results of the case study. These results, as well as the analytical procedure, should be of interest to engineers responsible for providing low-volume roads in developing countries.

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Kiattikomol, Vasin. « Freeway crash prediction models for long-range urban transportation planning ». 2005. http://etd.utk.edu/2005/KiattikomolVasin.pdf.

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Thesis (Ph. D.) -- University of Tennessee, Knoxville, 2005.
Title from title page screen (viewed on September 1, 2005). Thesis advisor: Arun Chatterjee. Document formatted into pages (xiv, 127 p. : ill. (some col.)). Vita. Includes bibliographical references (p. 119-126).

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Ma, Jianming 1972. « Bayesian multivariate poisson-lognormal regression for crash prediction on rural two-lane highways ». 2006. http://hdl.handle.net/2152/13068.

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Livres sur le sujet "Express highways Mathematical models"

Horton, J. P. Relationship of private entrances to highway efficiency. Downsview, Ont : Research and Development Branch, Ontario Ministry of Transportation, 1988.

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Aerde, M. Van. Review of freeway corridor traffic models. Downsview, Ont : Research and Development Branch, 1987.

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Jacobson, Eldon L. Evaluation of the TRAF family of models : Testing of the CORFLO and FRESIM models : final report, Research Project GC 8286, Task 17, TRAF Software for I-405 Lane Construction. [Olympia, Wash.?] : Washington State Dept. of Transportation, Washington State Transportation Commission, Transit, Research, and Intermodal Planning (TRIP) Division, in cooperation with U.S. Dept. of Transportation, Federal Highway Administration, 1992.

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Maze, T. H. Work zone simulation model : Companion report for traffic management strategies for merge areas in rural interstate work zones. Ames, Iowa : Center for Transportation Research and Education, Iowa State University, 1999.

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Barr, Paul. Live load distribution factors for Washington State SR 18/SR 516 overcrossing. [Olympia, Wash.] : Washington State Dept. of Transportation, 2000.

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Fyedotov, Grigoriy. Engineering geodesy. ru : INFRA-M Academic Publishing LLC., 2016. http://dx.doi.org/10.12737/13161.

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Fundamentals of engineering geodesy are stated, its value in a national economy and defense of the country is shown. Unlike earlier published textbooks in the present edition except traditional data on engineering geodesy information on the digital cards used in GIS geographic information systems, and also to the digital TsMM and mathematical MMM models of the district which are a basis of the modern automated design of SAPR on the engineering and geodetic methods and processes which incorporated the last achievements of computer technologies is given: electronic and computer takheometriya, satellite navigation, remote sensing, laser scanning, digital fotogrammetriya. In the textbook modern experience of works at researches and construction of highways and airfields, bridge crossings and transport tunnels of the leading design and survey organizations and firms of Russia is generalized. For students of automobile and road and construction specialties of higher education institutions. It can be used by the students of the corresponding specialties of technical schools, colleges, certified specialists working in the corresponding areas of transport construction.

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S, Miller John, Virginia. Dept. of Transportation. et Virginia Transportation Research Council, dir. The transferability of safety-driven access management models for application to other sites. Charlottesville, Va : Virginia Transportation Research Council, 2000.

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Abraham, Ralph. On Morphodynamics : Selected Papers (Science frontier express series). Aerial Pr, 1986.

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Mathematical Adventures in Performance Analysis : From Storage Systems, Through Airplane Boarding, to Express Line Queues. Birkhäuser, 2014.

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Bachmat, Eitan. Mathematical Adventures in Performance Analysis : From Storage Systems, Through Airplane Boarding, to Express Line Queues. Birkhäuser, 2016.

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Chapitres de livres sur le sujet "Express highways Mathematical models"

Chen, Yan, Graham H. Rong et Jianhua Chen. « Fabric Database and Fuzzy Logic Models for Evaluating Fabric Performance ». Dans Database Technologies, 2166–91. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-60566-058-5.ch132.

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A Web-based fabric database is introduced in terms of its physical structure, software system architecture, basic and intelligent search engines, and various display methods for search results. A fuzzy linear clustering method is used to predict fabric drape coefficient from fabric mechanical and structural properties. Experimental data indicate that fuzzy linear clustering is quite effective for this purpose. A hybrid method combining fuzzy linear clustering with K-nearest neighbor is also applied for the prediction of the fabric drape coefficient with improved prediction accuracy. The study also reveals that the fuzzy linear clustering method can also be used for predicting fabric tailorability with good prediction accuracy. Mathematical principles of fuzzy comprehensive evaluation are summarized and a typical application for assessing fabric comfort is exhibited. Through the fuzzy calculation, a single numerical value is produced to express female preferences for six fabric types for use in blouses, slacks, and underpants with respect to fabric property changes in an incremental-wear trial. Finally, a neuro-fuzzy computing technique for evaluating nonwoven fabric softness is presented. The combinational use of the fuzzy logic models (CANFIS) and the neural network method makes a significant step toward launching a fabric database application for neural network computing as a routine laboratory evaluation.

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Leigh, R. John, et David S. Zee. « The Saccadic System ». Dans The Neurology of Eye Movements, 169–288. Oxford University Press, 2015. http://dx.doi.org/10.1093/med/9780199969289.003.0004.

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This chapter reviews the behavioral properties of rapid eye movements, ranging from quick phases of nystagmus to cognitively controlled saccades, and their neural substrate. Properties of various types of saccades are described, including express saccades, memory-guided saccades, antisaccades, and saccades during visual search and reading. Current concepts of regions important for the generation of saccades are reviewed, integrating results of functional imaging and electrophysiology, including brainstem burst neurons and omnipause neurons, the superior colliculus, frontal eye field, supplementary eye field, dorsolateral prefrontal cortex, cingulate cortex, posterior parietal cortex, parietal eye field, thalamus, pulvinar, caudate, substantia nigra pars reticulata, subthalamic nucleus, cerebellar dorsal vermis, and fastigial nucleus. Saccade adaptation to novel visual demands is discussed, and the interaction between saccades and eyelid movements (blinks). Mathematical models of saccades are discussed. Clinical and laboratory evaluation of saccades and the pathophysiology of saccadic disorders, from slow saccades to opsoclonus, are reviewed.

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Binda, Luigia, et Giuliana Cardani. « Seismic Vulnerability of Historic Centers ». Dans Architecture and Design, 1114–41. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-7314-2.ch042.

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A methodology of investigation and diagnosis on the built patrimony of historic centres in seismic areas is presented with the aim of collecting an extensive knowledge on the structural typologies and behaviour of historic masonry buildings. This investigation is also the base for the prevention and/or repair of damages caused by earthquakes. Small historic centres or residential buildings in larger centres have been considered for long time as “minor architecture”, but they are meaningful testimonies of the local cultural heritage and express the evolution of a society and of its cultural identity. The results of the investigation carried out on different Italian historic centers, allowed also a critical review of the reliability of the analytical models and of the effectiveness of the repair techniques applied in the past decades. The guidelines emerging from the research results are here presented. A “minimal” diagnostic investigation program is also suggested, in order to support the designers in their projects and to set up appropriate mathematical models to study the vulnerability of the structures.

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Binda, Luigia, et Giuliana Cardani. « Seismic Vulnerability of Historic Centers ». Dans Handbook of Research on Seismic Assessment and Rehabilitation of Historic Structures, 1–29. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-8286-3.ch001.

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Sadrnia, Abdolhossein, Hossein Nezamabadi-Pour, Mehrdad Nikbakht et Napsiah Ismail. « A Gravitational Search Algorithm Approach for Optimizing Closed-Loop Logistics Network ». Dans Meta-Heuristics Optimization Algorithms in Engineering, Business, Economics, and Finance, 616–38. IGI Global, 2013. http://dx.doi.org/10.4018/978-1-4666-2086-5.ch020.

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Since late in the 20th century, various heuristic and metaheuristic optimization methods have been developed to obtain superior results and optimize models more efficiently. Some have been inspired by natural events and swarm behaviors. In this chapter, the authors illustrate empirical applications of the gravitational search algorithm (GSA) as a new optimization algorithm based on the law of gravity and mass interactions to optimize closed-loop logistics network. To achieve these aims, the need for a green supply chain will be discussed, and the related drivers and pressures motivate us to develop a mathematical model to optimize total cost in a closed-loop logistic for gathering automobile alternators at the end of their life cycle. Finally, optimizing total costs in a logistic network is solved using GSA in MATLAB software. To express GSA capabilities, a genetic algorithm (GA), as a common and standard metaheuristic algorithm, is compared. The obtained results confirm GSA’s performance and its ability to solve complicated network problems in closed-loop supply chain and logistics.

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Koch, Christof. « Phase Space Analysis of Neuronal Excitability ». Dans Biophysics of Computation. Oxford University Press, 1998. http://dx.doi.org/10.1093/oso/9780195104912.003.0013.

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The previous chapter provided a detailed description of the currents underlying the generation and propagation of action potentials in the squid giant axon. The Hodgkin-Huxley (1952d) model captures these events in terms of the dynamical behavior of four variables: the membrane potential and three state variables determining the state of the fast sodium and the delayed potassium conductances. This quantitative, conductance-based formalism reproduces the physiological data remarkably well and has been extremely fertile in terms of providing a mathematical framework for modeling neuronal excitability throughout the animal kingdom (for the current state of the art, see McKenna, Davis, and Zornetzer, 1992; Bower and Beeman, 1998; Koch and Segev, 1998). Collectively, these models express the complex dynamical behaviors observed experimentally, including pulse generation and threshold behavior, adaptation, bursting, bistability, plateau potentials, hysteresis, and many more. However, these models are difficult to construct and require detailed knowledge of the kinetics of the individual ionic currents. The large number of associated activation and inactivation functions and other parameters usually obscures the contributions of particular features (e.g., the activation range of the sodium activation particle) toward the observed dynamic phenomena. Even after many years of experience in recording from neurons or modeling them, it is a dicey business predicting the effect that varying one parameter, say, the amplitude of the calcium-dependent slow potassium current (Chap. 9), has on the overall behavior of the model. This precludes the development of insight and intuition, since the numerical complexity of these models prevents one from understanding which important features in the model are responsible for a particular phenomenon and which are irrelevant. Qualitative models of neuronal excitability, capturing some of the topological aspects of neuronal dynamics but at a much reduced complexity, can be very helpful in this regard, since they highlight the crucial features responsible for a particular behavior. By topological aspects we mean those properties that remain unchanged in spite of quantitative changes in the underlying system. These typically include the existence of stable solutions and their basins of attraction, limit cycles, bistability, and the existence of strange attractors.

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Actes de conférences sur le sujet "Express highways Mathematical models"

Longley, John P. « A Review of Non-Steady Flow Models for Compressor Stability ». Dans ASME 1993 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1993. http://dx.doi.org/10.1115/93-gt-017.

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This paper presents a review of the different approaches to modelling the non-steady fluid dynamics associated with two-dimensional compressor flowfields. These models are used to predict the time development of flowfield disturbances and have been found useful both in the study of rotating stall and the development of active control. The opportunity to digest the earlier investigations has now made it possible to express the modelling ideas using only a very simple mathematical treatment. Here, the emphasis is on the underlying physical processes that the models simulate and how the assumptions within the models affect predictions. The purpose of this work is to produce, in a single document, a description of compressor modelling techniques, so that prospective users can assess which model is the most suitable for their application.

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Yekula, Ravi K., Daniel A. McAdams et Robert B. Stone. « Functional and Mathematical Equivalence of Mechanisms : A Novel Approach to Integrating Synthesis and Design Analysis ». Dans ASME 2003 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/detc2003/dtm-48663.

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The objective of our research is to produce classical engineering design analysis models in conjunction with the employment of function based synthesis techniques. As a part of this goal, we define a design approach to construct parametric design models from functional models. Such an approach allows a natural progression from functional product models, to synthesis, to analysis, and then to initial parameter specification. An empirical study is performed to gather product data from a jigsaw and a palm sander. Our method starts by creating a black box model and a functional model of a product. From the functional model, a critical flow and an associated function chain are identified. The next step is to express each component at a functional level. Following that, components are mapped to equations describing their performance and finally, functions are mapped to equations. We analyze product data that is collected following the above described steps and discover functional and mathematical similarities between a scotch yoke mechanism in a jigsaw and an eccentric cam in a palm sander; in this case, two mechanisms used to perform the same function. We derive general performance equations for functions based on the components that are functionally similar but differing in form.

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Shibasaki, Satoshi, et Hideki Aoyama. « Development of Wood Grain Pattern Design System ». Dans ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/detc2009-87094.

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Various approaches for generating woodgrain patterns using computer graphics have been proposed so far. However, the generation of various woodgrain patterns with conventional methods is difficult due to the need for the adjustment of numerous parameters to express a real woodgrain pattern. In this paper, a new mathematical approach for generating woodgrain patterns is proposed. Virtual trees are generated by simulating tree growing based on past actual weather information obtained from public organizations, and woodgrain patterns are then acquired by cutting the trunks of the virtual trees. In order to simulate tree growing, growth models of tree are constructed in consideration of dendrological characteristics and environmental conditions. Growth of tree is influenced by various environmental factors, such as sunlight, temperature, carbon dioxide concentration, wind, precipitation, soil nutrient, inclination of ground, survival amongst surrounding trees, etc. With this system, the growth model of trees is constructed based on precipitation, temperature, sunlight, and inclination of ground, which especially have strong effects on tree growth. With this approach, various types of virtual trees can be obtained by changing growth conditions such as period and location of growth without the need to reset complicated parameters of tree species, and then the virtual trees can be cut at arbitrary areas, thus allowing a variety of woodgrain patterns to be easily generated by one parameter setup.

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Petrov, E. P. « Analytical Formulation of Friction Contact Elements for Frequency-Domain Analysis of Nonlinear Vibrations of Structures With High-Energy Rubs ». Dans ASME Turbo Expo 2019 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-90628.

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Abstract In gas-turbine engines and other rotating machinery structures rubbing contact interactions can occur when the contacting components have large relative motion between components: such as in rotating bladed disc-casing rubbing contacts, rubbing in rotor bearing and labyrinth seals, etc. The analysis of vibrations of structures with rubbing contacts requires the development of a mathematical model and special friction contact elements that would allow for the prescribed relative motion of rubbing surfaces in addition to the motion due to vibrations of the contacting components. In the proposed paper, the formulation of the friction contact elements is developed which includes the effects of the prescribed relative motion on the friction stick-slip transitions and, therefore, on the contact interaction forces. For a first time, the formulation is made for the frequency domain analysis of coupled rubbing and vibrational motion, using the multiharmonic representation of the vibration displacements. The formulation is made fully analytically to express the multiharmonic contact interaction forces and multiharmonic tangent stiffness matrix in an explicit analytical form allowing their calculation accurately and fast. The dependency of the friction and contact stiffness coefficients on the energy dissipated during high-energy rubbing contacts and, hence, on the corresponding increase of the contact interface temperature is included in the formulation. The efficiency of the developed friction elements is demonstrated on a set of test cases including simple models and a large-scale realistic blade.

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Premasiri, A., G. Happawana et A. Rosen. « Porous Media Tumor Model for Light Penetration and Oxygen Diffusion During Photodynamic Therapy ». Dans ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-66480.

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Photodynamic therapy (PDT) is an FDA approved, effective, and minimally invasive cancer treatment modality with few side effects. PDT requires three major components; photosensitizing agent, activation light, and molecular oxygen. Optimization of PDT for an individual patient requires good therapeutic selectivity and high efficacy, where the design of such an effective protocol is based on the understanding of the interaction of key therapeutic components with tumor tissue. Tumor models expressive of changes during the growth of tumor along with the behavior of PDT components facilitate the above requirement. In this study we have developed a mathematical model considering tumor as a porous medium of solid of and liquid that enables to express characteristics of a growing tumor. The characteristic lengths and the volumes that can be changed in the model represent the dynamic changes during the growth of the tumor. An energy based light transport model is superimposed with the porous media model to yield an analytical equation of light penetration in turbid media. In addition a molecular diffusion model combined with the porous media tumor model provides a second analytical equation yielding molecular oxygen diffusion during PDT. Experimentally available physiological and photophysical data are used to obtain the results from the developed models. The commonly used wavelength for PDT, 635nm and corresponding photophsical parameters for a healthy tissue are used for the calculations. The modeling results reveal an exponential decay of optical power along the direction of light penetration and the characteristic changes in oxygen diffusion during PDT. Further observations include the time dependent changes in photosensitizer photobleaching and the corresponding increase in oxygen diffusion length. The modeling results in both cases show a promising accordance with the available experimental results in literature. The model calculations also reveal the effect of light penetration on oxygen diffusion in PDT milieu adding to the expression of its usefulness.

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Marani, Pietro, et Cristian Ferrari. « Suppression of High Frequency Oscillations on Suspension System of Snow Groomer With Evolutionary Algorithms Optimization ». Dans 9th FPNI Ph.D. Symposium on Fluid Power. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/fpni2016-1534.

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In current engineering practice for the design and dimensioning of hydropneumatic suspension systems, the effect of main parameters is considered; this approach can be used to implement approximate models basically suitable to describe low frequency and high amplitude oscillations of the machine. The target of this study is a Snow Groomer, a tracked vehicle driven by diesel engines and equipped in front with a shovel and behind with a cutter. When the machine drives over a snowfield, it pushes snow ahead of it and, at the same time, smooths out any surface unevenness. The suspension system is the key element to ensure the driver’s safety and comfort, the effectiveness of snow grooming and finally enhance the reliability of the machine components. The on-field testing had shown high frequency pressure oscillations transmitted from the sprocket to hydraulic system, propagated through the flexible hoses. Those Pressure Oscillations cause noise and can affect negatively the durability and reliability of the Machine. A lumped parameter non-linear dynamic model of the hydraulic circuit and of the machine interactions is built in Amesim environment, including Lax Wendroff wave propagation models, to make it able to catch the high frequency oscillations experienced in the test field. Most of the design parameters are fixed (such as vehicle weight and hydraulic lines length), other parameters can be varied to study the optimal solution, these parameters define the “factors” of the optimization problem. As a next step it is important to define the objectives of the optimization, in this case corresponding to various figures of merit describing the behavior of the system in different work conditions. The large number of factors included in the lumped parameter model generates an exponentially larger number of possible configurations. Moreover the relationship between factors and objective is not always possible to express with explicit mathematical models. Finally the presence of multiple and sometimes conflicting objectives forces more refined analysis methods to be adopted. For the above mentioned reasons a Multi-objective Optimization method is proposed taking advantage of Evolutionary Algorithms and Pareto Front optimization. Two different architectural solutions are analyzed and optimized using two different algorithms, Non Sorting Genetic Algorithm II (NSGAII) and Multiple Object Swarm Particle Optimization Algorithm (MOPSO). The results of the optimization belonging to the Pareto Front will be analyzed to assess the expected improvement of the suspension performance and will be chosen as candidates for a new setting of the Snow Groomer. Furthermore a comparison in terms of effectiveness and speed in finding solutions will be given for the current simulation environment.

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