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PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS 2013年第5期250卷 931-936页

作者： Wright, A. C. Thorpe, M. F. Univ Reading JJ Thomson Phys Lab Reading RG6 6AF Berks England Arizona State Univ Dept Phys Tempe AZ 85287 USA Univ Oxford Dept Theoret Phys Oxford OX1 3NP England

The 80 years since Zachariasen's famous paper, 20 years before Stephen Elliott was born, on the random network theory of glass structure have seen remarkable progress in our understanding of the structure of glassy materials through the construction of models and comparison with experiment. In the early days, models were hand-built with plastic units and had free boundary conditions. Today, very much larger computer models have periodic boundary conditions. We recount the progress that has been made in the last 80 years, and discuss the current agreement between models and experiments that remains imperfect. Stephen Elliott's work on medium range order forms an important part of the history of this subject.

关键词： computer models diffraction random network vitreous silica

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Optimized schedules for airline routes

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JOURNAL OF TRANSPORTATION ENGINEERING 2004年第4期130卷 412-418页

作者： Chang, SW Schonfeld, P Univ Maryland Dept Civil & Environm Engn College Pk MD 20742 USA ROC Minister Natl Def Div IAD Taipei Taiwan

Increasing flight frequency on airline routes tends to reduce. user delay costs but increase airline operating costs. Flight frequency should vary as demand intensity changes at various times of day. models are presented here for optimizing the departure times of flights on single airline routes with time-dependent demand. An analytic model is developed to find the departure times that minimize average schedule delay per passenger for given flight frequencies and to identify the algebraic relations among the variables. Using an analytic approach, the departure times of flights that minimize airline operating cost and users' waiting cost are determined. To minimize the objective function, it is found that the headways should be inversely proportional to the square root of demand intensity near the departure times. computer models for both cost minimization and profit maximization are developed to solve the problems with relaxed assumptions and verify the numerical results obtained analytically.

关键词： airlines optimization scheduling routes computer models costs

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Image-Based Machine Learning for Reduction of User Fatigue in an Interactive Model Calibration System

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JOURNAL OF COMPUTING IN CIVIL ENGINEERING 2010年第3期24卷 241-251页

作者： Singh, Abhishek Minsker, Barbara S. Bajcsy, Peter INTERA Inc Austin TX 78759 USA Univ Illinois Dept Civil & Environm Engn Urbana IL 61801 USA Univ Illinois Natl Ctr Supercomp Applicat Urbana IL 61801 USA

The interactive multiobjective genetic algorithm (IMOGA) is a promising new approach to calibrate models. The IMOGA combines traditional optimization with an interactive framework, thus allowing both quantitative calibration criteria as well as the subjective knowledge of experts to drive the search for model parameters. One of the major challenges in using such interactive systems is the burden they impose on the experts that interact with the system. This paper proposes the use of a novel image-based machine-learning (IBML) approach to reduce the number of user interactions required to identify promising calibration solutions involving spatially distributed parameter fields (e.g., hydraulic conductivity parameters in a groundwater model). The first step in the IBML approach involves selecting a few highly representative solutions for expert ranking. The selection is performed using unsupervised clustering approaches from the field of image processing, which group potential parameter fields based on their spatial similarities. The expert then ranks these representative solutions, after which a machine-learning model (augmented with the spatial information of the selected fields) is trained to learn user preferences and predict rankings for solutions not ranked by the expert. To better mimic the "visual" information processing of human experts, algorithms from the field of image processing are used to mine information about the spatial characteristics of parameter fields, thus improving the performance of the clustering and machine-learning algorithms. The IBML approach is tested and demonstrated on a groundwater calibration problem and is shown to lead to significant improvements, reducing the amount of user interaction by as much as half without compromising the solution quality of the IMOGA.

关键词： Algorithms Calibration computer models Groundwater Human factors Imaging techniques

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Combinatorial Algorithm for Optimizing Wood Waste in Framing Designs

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JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT-ASCE 2011年第3期137卷 188-197页

作者： Manrique, Juan D. Al-Hussein, Mohamed Bouferguene, Ahmed Safouhi, Hassan Nasseri, Reza Univ Alberta Dept Civil & Environm Engn Hole Sch Construct Markin CNRL Nat Resources Engn Facil 1 080 Edmonton AB T6G 2W2 Canada Univ Alberta Dept Math Edmonton AB T6G 2M7 Canada Landmark Grp Builders Edmonton AB T6E 5J4 Canada 3 011 Markin CNRL Nat Resources Engn Facil Dept Civil & Environm Engn Hole Sch Construct Edmonton AB T6G 2W2 Canada

As a result of elevated labor costs, a shortage of trades personnel, and a lack of efficient construction methods, many construction companies in western Canada waste primary materials. In general, these firms suffer from a lack of effective construction guidelines and process standardizations. This paper focuses on the use of a mathematical algorithm, referred to here in this paper as CUTEX, which maximizes the use of wood materials for platform-framing residential construction. In particular, CUTEX is designed to reduce waste by generating a cutting list for wood studs and sheathing (oriented strand boards-OSB). A combinatorial analysis algorithm has been developed and applied to determine the best cutting procedure for wood stick frame houses. Restrictions, such as nominal lumber dimensions and sizes encountered in the North American market, were taken into account. A two-dimensional optimization for sheathing layout has also been developed to minimize the disposal of OSB boards, making the construction process leaner and more economical. A direct and positive impact on the environment and a reduction in construction costs are expected as a result of reducing the amount of primary materials utilized. DOI: 10.1061/(ASCE)CO.1943-7862.0000117. (c) 2011 American Society of Civil Engineers.

关键词： Algorithm optimization Automation computer-aided drafting (CAD) computer models Construction materials Cutoffs Frame design

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DECISION SUPPORT SYSTEM FOR ESTUARINE WATER-QUALITY MANAGEMENT

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JOURNAL OF WATER RESOURCES PLANNING AND MANAGEMENT-ASCE 1990年第3期116卷 417-432页

作者： CAMARA, AS DASILVA, MC RODRIGUES, AC REMEDIO, JM CASTRO, PP DEOLIVEIRA, MJS FERNANDES, TF INTEGRATED MANAGEMENT PROJECT WATER RESOURCES RIVE LISBON PORTUGAL CLEMSON UNIV DEPT ENVIRONM SYST ENGN CLEMSON SC 29631 USA UNIV ABERDEEN DEPT ZOOL ABERDEEN AB9 1FX SCOTLAND

A decision support system for the water‐quality management of the Tejo estuary, named Hypertejo, is presented. Hypertejo is based on a chain of data bases, dispersion, nonpoint pollution, and regional water‐quality management models. Due to large running times of some of the models, making their interactive use impossible, Hypertejo was designed as a synthesis of the interconnected data bases and models. This synthesis was achieved by applying descriptive statistics and transfer function concepts. The system, implemented using HyperCard, provides answers to questions posed by three levels of users: member of the government, mayor, and technical manager. Hypertejo implementation for a pilot zone in the estuary is used to illustrate the potential applications of similar systems in water‐quality management studies.

关键词： Water quality Decision support systems Information systems Nonpoint pollution computer models Databases Estuaries

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computer-Designed Implants for Fronto-Orbital Defect Reconstruction

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FACIAL PLASTIC SURGERY 2008年第1期24卷 22-34页

作者： Frodel, John L., Jr. Geisinger Med Ctr Dept Otolaryngol Head & Neck Surg Facial Plast Surg & Geisinger Multidisciplinan Co Danville PA 17822 USA Atlanta Med Day Spa Atlanta GA USA

Patients with complex defects of the frontal and orbital regions present a myriad of problems for the reconstructive surgeon. In this review, options that allow state-of-the-art reconstruction using computer-assisted implants will be illustrated. The advantages of such implants created with computer assistance will be reviewed as well as indications for their use.

关键词： computer generation computer models porous polyethylene cranial defects orbital defects

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Theoretical optimization of pulmonary-to-systemic flow ratio after a bidirectional cavopulmonary anastomosis

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AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY 1998年第2期274卷 H694-H700页

作者： Santamore, WP Barnea, O Riordan, CJ Ross, MP Austin, EH Univ Louisville Dept Surg Div Thorac & Cardiovasc Surg Louisville KY 40292 USA Tel Aviv Univ Dept Biomed Engn IL-69978 Tel Aviv Israel Kosair Childrens Hosp Dept Pediat Louisville KY 40292 USA

A univentricle with parallel pulmonary and systemic circulations is inherently inefficient because mixing of pulmonary and systemic venous return occurs. Thus a cavopulmonary anastomosis is used as a staged palliative procedure to reduce volume overload in patients with cyanotic congenital heart disease. On the basis of oxygen uptake and consumption, an equation was derived that related cardiac output, pulmonary venous oxygen saturation, upper body oxygen consumption, and superior-to-inferior vena caval blood flow ratio (Q(SVC)/Q(IVC)) to oxygen delivery. The primary findings were as follows. 1) As Q(SVC)/Q(IVC) increases, total body oxygen delivery and arterial and superior vena caval oxygen saturations increase. 2) As Q(SVC)/Q(IVC) increases, lower body oxygen delivery and inferior vena caval oxygen saturation initially increase, then peals, and then decrease, 3) As the percentage of lower body oxygen consumption increases, oxygen delivery and saturation decrease, 4) A cavopulmonary anastomosis decreases the required cardiac output for a given oxygen delivery. Thus we concluded that a high systemic arterial oxygen saturation after cavopulmonary anastomosis requires a high percentage of upper body oxygen consumption and a high Q(SVC)/Q(IVC) and that the cavopulmonary anastomosis reduces the volume load on the single ventricle.

关键词： hypoplastic left heart syndrome pulmonary blood flow aortic blood flow computer models infants

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Oak forest carbon and water simulations: Model intercomparisons and evaluations against independent data

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ECOLOGICAL MONOGRAPHS 2004年第3期74卷 443-489页

作者： Hanson, PJ Amthor, JS Wullschleger, SD Wilson, KB Grant, RF Hartley, A Hui, D Hunt, ER Johnson, DW Kimball, JS King, AW Luo, Y McNulty, SG Sun, G Thornton, PE Wang, S Williams, M Baldocchi, DD Cushman, RM Oak Ridge Natl Lab Div Environm Sci Oak Ridge TN 37831 USA NOAA Atmospher Turbulence Diffus Div Oak Ridge TN 37840 USA Univ Alberta Edmonton AB T6G 2E3 Canada Florida Int Univ Dept Environm Studies Miami FL 33199 USA Univ Oklahoma Dept Bot & Microbiol Norman OK 73019 USA USDA ARS Hydrol & Remote Sensing Lab Beltsville MD 20705 USA Univ Nevada Reno NV 89512 USA Univ Montana Flathead Lake Biol Stn Polson MT 59860 USA Univ Montana Sch Forestry Polson MT 59860 USA USDA US Forest Serv So Global Change Program Raleigh NC 27606 USA Natl Ctr Atmospher Res Boulder CO 80503 USA Canada Ctr Remote Sensing Ottawa ON K1A 0Y7 Canada Univ Edinburgh Sch Geosci Edinburgh EH9 3JU Midlothian Scotland Univ Calif Berkeley Ecosyst Sci Div Dept Environm Sci Berkeley CA 94720 USA

models represent our primary method for integration of small-scale, process-level phenomena into a comprehensive description of forest-stand or ecosystem function. They also represent a key method for testing hypotheses about the response of forest ecosystems to multiple changing environmental conditions. This paper describes the evaluation of 13 stand-level models varying in their spatial, mechanistic, and temporal complexity for their ability to capture intra- and interannual components of the water and carbon cycle for an upland, oak-dominated forest of eastern Tennessee. Comparisons between model simulations and observations were conducted for hourly, daily, and annual time steps. Data for the comparisons were obtained from a wide range of methods including: eddy covariance, sapflow, chamber-based soil respiration, biometric estimates of stand-level net primary production and growth, and soil water content by time or frequency domain reflectometry. Response surfaces of carbon and water flux as a function of environmental drivers, and a variety of goodness-of-fit statistics (bias, absolute bias, and model efficiency) were used to judge model performance. A single model did not consistently perform the best at all time steps or for all variables considered. Intermodel comparisons showed good agreement for water cycle fluxes, but considerable disagreement among models for predicted carbon fluxes. The mean of all model outputs, however, was nearly always the best fit to the observations. Not surprisingly, models missing key forest components or processes, such as roots or modeled soil water content, were unable to provide accurate predictions of ecosystem responses to short-term drought phenomenon. Nevertheless, an inability to correctly capture short-term physiological processes under drought was not necessarily an indicator of poor annual water and carbon budget simulations. This is possible because droughts in the subject ecosystem were of short duration and ther

关键词： autotrophic respiration carbon budget computer models evaporation evapotranspiration NEE NPP transpiration water budget

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COST MODEL FOR REINFORCED-CONCRETE BEAM AND SLAB STRUCTURES IN BUILDINGS

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JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT-ASCE 1990年第1期116卷 54-67页

作者： SINGH, S Assoc. Prof. School of Building and Estate Mgmt. Fac. of Arch. and Building Nat. Univ. of Singapore Singapore‐0511 Republic of Singapore

An interactive, computer‐based cost model has been developed for approximate cost estimation of reinforced concrete beam and slab construction in high‐rise commercial buildings. A number of design variables, such as different structural schemes, grid sizes, number of stories, grades of concrete, grid locations, and section of beams, have been incorporated in the model to assess their effect on cost and quantities of constituents of concrete construction. The use of the model is recommended for comparative cost estimation to determine the effect of design parameters on structural cost; for approximate structural‐cost estimation of an overall project; for checking of estimates for structural works; for calculation of quantity index for structural schemes and system; for budgeting of materials, and, finally, for use in various studies in building economics.

关键词： computer models Concrete beams Cost estimates Cost analysis Concrete reinforced Economic factors Building design

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The application of multi-criteria (AHP-PROMETHEE) decision-making methods in selecting and prioritizing the green area irrigation resources

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INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY 2021年第5期18卷 1135-1146页

作者： Safari, A. Abbaspour, M. Javid, A. H. Islamic Azad Univ Dept Nat Resources & Environm Sci & Res Branch Tehran Iran Sharif Univ Technol Sch Mech Engn Tehran Iran

One of the underlying factors in the conservation and development of urban green spaces is the available water resources use for green areas in each region. The primary purpose of this study is to introduce the integration of a proper simulation method for runoff along with AHP-PROMETHEE decision-making method for water resources management in urban basins. The application of this approach was investigated in the city Buin Zahra of Qazvin Province of Iran. In the first step by using the analytic hierarchy process (AHP), the available water resources in the case study were weighted. In the second step, the water resources of the municipal and residential wells and water collected by precipitation and flooding were investigated to provide irrigation water. The Storm Water Management Model was applied to optimize water resources use from the flood as a solution to save potable water. The simulation was performed for precipitation with a return period of 5 and 10 years, for 6-h intervals. The simulation results were carried out for a total of 25 nodes, and the discharge was calculated, which is between 0.95 up to 1.2 cubic meters per second. The flow of the resulting discharge can feed the required water for green areas. Also, the available water resources in the case study were weighted by Expert Choice and were finally selected by using the Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE). The results indicated that residential wells had the priority in supplying irrigation water for green areas.

关键词： Watershed Rainfall-runoff Urban basins Urban green spaces Urban drainage network computer models Simulation Irrigation water SWMM

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