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Under the fair open-access operation mode of gas pipeline network facilities, the accurate evaluation of the remaining capacity of a gas pipeline network can help to grasp the load rate of the pipelines, and the remaining capacity can be sold to the market to increase the utilization rate of the pipelines. In this paper, the indices of the remaining capacity of injection nodes, delivery nodes, and the pipeline system are proposed, and the theoretical as well as actual remaining capacity under different gas allocation principles are analyzed. Mathematical optimization models considering the physical, legal, and gas allocation constraints are established to evaluate the remaining capacity of nodes and pipeline systems. All the mathematical optimization models established are nonlinear programming models, which are solved using the interior-point method. The indices and mathematical models proposed for the remaining capacity are verified using a gun-barrel and branch-structured pipeline system, meanwhile, the results of the theoretical and actual remaining capacity of nodes as well as pipeline systems under different gas allocation rules are compared and analyzed in detail. [ABSTRACT FROM AUTHOR]

The article features the two paper selected for the Outstanding Paper Award. The paper by Gianni Bartoli and Michele Betti "Cappella dei Principi in Firenze, Italy: Experimental Analyses and Numerical Modeling for the Investigation of a Local Failure" focuses on structural system in a historical building. The paper by Clay Naito, Daniel Cox, Qi-Song Yu, and Hillary Brooker "Fuel Storage Container Performance during the 2011 Tohoku, Japan, Tsunami" features photographs from field observations.

Blockage, which arises from accumulated materials like sand, stones, sediment, uncontrolled growth of tree roots within pipes, and the inadvertent partial closure of in-line valves, poses a pervasive challenge in the operational sphere of water distribution networks (WDNs). This results in significant head loss in the pipes, leading to disruptions in the water supply. Identifying such blockages conventionally requires specialized human resources and is often encumbered by cost and time challenges. This paper introduces a method for precisely determining the location and magnitude of blockages within WDNs. This methodology is firmly grounded in a calibration-optimization framework, harnessing a specially crafted hybrid optimization algorithm known as PSOHS, which combines the strengths of particle swarm optimization (PSO) and harmony search (HS) algorithms. Detailed comparisons are drawn between simulated pressure data (derived from the hydraulic network model) and corresponding field data at multiple points to minimize disparities, thereby facilitating the precise identification of potential blockages in a WDN. The proposed method undergoes rigorous evaluation across two benchmark networks (modified Poulakis and Hanoi) under diverse scenarios as well as on an actual WDN. Results from over 60,000 simulated blockage scenarios underscore the method's remarkable proficiency, achieving blockage localization accuracy of 99.9% and magnitude estimation with a maximum absolute error (MAE) of less than 3%. Particularly noteworthy is the superior performance of the PSOHS algorithm as proposed, surpassing the PSO algorithm by enhancing blockage localization accuracy by a minimum of 10.5% and reducing MAE by 3%. Further, adopting the proposed algorithm over the HS algorithm yields improvements of 27.5% and 3.5%, respectively. Applying the proposed method in an actual network effectively pinpointed its blockage. Consequently, this algorithm presents a valuable tool for WDN operators, augmenting their capacity for effective network management. [ABSTRACT FROM AUTHOR]

Vortex-induced vibration (VIV) is a critical problem for high-rise buildings. Thus, accurate prediction of aerodynamic damping becomes a key problem in the wind-resistant design of high-rise buildings. A common feature of the existing aerodynamic damping models is that most of their model parameters are functions of wind velocity. Such a feature leads to the inconvenience of users because the parameters need to change from case to case. This paper proposes an aerodynamic damping model that is a function of structure responses only. That means it does not need to adjust its parameters in different wind speeds. A single-degree-of-freedom aeroelastic square section high-rise building model with different structural damping ratios is tested in a wind tunnel for the analytical modeling. According to the identified aerodynamic damping coefficients and its relation with response amplitudes, the nonlinear aerodynamic damping model is proposed. It is a polynomial-type function of the instantaneous velocity and displacement of the structure. The results show that predicted responses, by using one set of model parameters, are in good agreement with the experiment data in the whole tested wind speed range. These results suggest that the proposed aerodynamic model can be a generic model for prediction of wind-induced vibration. [ABSTRACT FROM AUTHOR]

The possibility of detuning resulting from liquid depth fluctuation and low damping characteristics for being deep tanks hinder the utilization of overhead water tanks (OWTs) as tuned sloshing dampers (TSDs). This paper proposes a slender TSD (STSD) that can effectively serve as OWT as well. Unlike conventional TSDs, in an STSD, the liquid depth is allowed to fluctuate within any practically feasible range maintaining the condition h/D≥1 , where h is the liquid depth and D is the tank dimension along excitation. For h/D≥1 , the frequency and the lumped mass representative of the fundamental sloshing mode become independent of h. To improve damping, STSDs are provided with equally spaced horizontal ring baffles. It is shown that the effective damping ratio of the STSD with equally spaced horizontal ring baffles also becomes practically constant for h/D≥1. Thus, a consistent damper performance is possible despite liquid depth fluctuation. The mathematical model of the damper system is described followed by the design of OWT cum STSD for a real-life apartment building. Significant seismic vibration control of the building by the damper is demonstrated through a numerical study that shows consistent performance by the STSD despite 66.7% liquid depth fluctuation in the tank. The performance of the STSD is found to be comparable with conventional TSD. [ABSTRACT FROM AUTHOR]

The article discusses various papers published within this issue including one by Barak et al. on building information modeling and another by Rasdorf et al. on information technology (IT) issues for the management of cost assets.

Pumping at a large rate can convert a confined flow to a confined–unconfined one in a confined aquifer. In this paper, a new semianalytical solution is proposed to investigate the mechanism of transient confined–unconfined flow under the non-Darcian condition in a fully penetrated confined aquifer. By using Izbash's equation, a new linearization method was developed to approximate the nonlinear terms of the mathematical model of pumping-induced flow. The solution was derived by using the Laplace transform. The acceptability of the proposed solutions was verified by comparisons with numerical solutions by COMSOL Multiphysics and an analytical solution. The effects of the non-Darcian index, hydraulic conductivity, and the storativity ratio on developments of drawdown and the transient unconfined region were especially investigated. It is indicated that the non-Darcian index and the hydraulic conductivity have a positive effect on the drawdown in the confined region and a negative effect on that in the confined region, respectively. Otherwise, the drawdown simulation is negatively related to the storativity ratio. The result of this paper offers much-needed insights in the field of mine dewatering and the application of geological and hydrological conditions. [ABSTRACT FROM AUTHOR]

Lists articles on hydraulic and civil engineering. Titles and authors of articles; Titles of periodicals in which the articles appeared; Modeling of low flows; Optimization of bioscrubber performances; Reservoir thermal structure; Operations of multireservoir systems; Energy equation for volatile liquid transport in porous media; Streamflow prediction.

Green roofs (GRs) are one of the best practices that researchers are promoting due to environmental, social, economic, and ecological benefits. This bibliometric review on GRs performs a comprehensive evaluation where shortlisted studies are categorized into empirical and nonempirical. A review of the nonempirical studies affirms the importance of GRs, and the appraisal of the empirical studies helps understand the performance evaluation methods. The performance of GRs largely depends on the overall assembly configuration, especially the vegetation and substrate layers, along with the site and settings. Such studies are conducted through field and laboratory experiments, simulation modeling, mathematical models, or combination methods. These methods help understand the thermal, hydrological and energy performance, urban heat island (UHI) mitigation, noise reduction, air pollution reduction, sustainability, and retrofitting potentials of GRs. This paper presents a comprehensive review of the performance evaluation methods to understand their association with performance parameters and variables. This will help identify an effective performance evaluation method for an inclusive evaluation of any GR assembly. [ABSTRACT FROM AUTHOR]

This paper examined the applicability of the pruned exact linear time (PELT) algorithm for optimal change-point analysis to delineate pavement into homogeneous sections based on road condition. The primary objective of the study was to address some of the limitations associated with existing delineation approaches, such as the AASHTO cumulative difference approach (CDA) and the Bayesian binary segmentation method. The paper presents a mathematical framework for the optimal change-point analysis of pavement deflection data collected on a runway of an international airport. Through an analytical comparative study, the paper demonstrated how the proposed approach is better than existing delineation methods in terms of accuracy in identifying the change points, flexibility in the choice of the number of homogeneous sections, and computational time. The approach provides an opportunity for practitioners and road agencies to integrate their experience and knowledge of the road network into decision-making about the location of change points and their count without compromising computational accuracy. The proposed method was found to be robust because the solutions are independent of the parameters chosen for the analysis. [ABSTRACT FROM AUTHOR]

A reply from author Ali R. Vatankhah in response to a review of his article "Evaluation of Explicit Numerical Solution Methods of the Muskingum Model" is presented.

Pipeline suspension bridges are narrow and wind sensitive. There is a lack of research on the mechanical performance of pipeline suspension bridges under wind load, especially under the action of gorge wind. This paper studies the aerodynamic stability of the typical pipeline suspension bridge under the action of wind load by conducting a wind tunnel test of a full-bridge aeroelastic model. Setting a p connection to replace and simulate the core beam stiffness avoids the impact of the core beam on the flow pattern of wind, making the wind-induced dynamic response results obtained from the test more like the practical situation. The results of the measurements of the model dynamical characteristics indicate that the structural dynamic characteristics of the full-bridge aeroelastic model is similar to that of the prototype. The test results show that under various operating conditions, the typical pipeline suspension bridge in the paper has sufficient aerodynamic stability in both a boundary-layer wind field and a turbulent flow field. Under various testing conditions and wind speeds, no flutter, galloping, or other aerodynamic instabilities occur, and no lateral deformation, divergent torsion, or other static instabilities occur. There are no clear vortex-induced vibrations in the lateral, vertical, and torsional directions of the model main beam. [ABSTRACT FROM AUTHOR]

By incorporating horizontal sediment transport and bed erosion into the two-layer depth-averaged shallow water system, one can construct a hydro-sediment-morphodynamic mathematical model in which a variable sediment concentration in a denser layer and interaction between underflows and ambient water are taken into account. Numerically solving such a promising system presents challenges due to its inherent mathematical properties of being conditionally hyperbolic and nonconservative. These properties may result in instability and incorrect results near sharp hydraulic gradients in numerical solutions. The major contribution of this paper is to develop a novel numerical scheme to overcome these issues and to allow the system to be extended to a wider range of engineering applications. To this end, for a one-dimensional two-layer hydro-sediment-morphodynamic system, (1) its mathematical model is first reformulated to a novel relaxation format, which is mathematically equivalent and unconditionally hyperbolic, by relaxing interlayer surface level, and (2) this relaxation system is then solved using a novel path-conservative numerical algorithm with new discrete formulas for the fluxes and nonconservative terms. Thus, the proposed numerical scheme ensures the well-balanced property, and has a major advantage in its ability to accurately and stably handle sharp hydraulic/density gradients with second-order accuracy. Several numerical and laboratory tests are conducted to demonstrate the performance of the proposed new scheme. [ABSTRACT FROM AUTHOR]

Large-scale public construction projects often become expensive white elephants requiring considerable postconstruction maintenance. Thus there is a pressing need to integrate construction and postconstruction stages into productivity measurement and analysis. However, previous studies of productivity measurement focused on the efficiency of the project delivery phase, but overlooked the utilization of the constructed facility. This paper developed a two-stage construction project productivity (CPP) measurement model by integrating site efficiency (SE) and utilization effectiveness to investigate strategies for improving the overall CPP. An as-usual setting, which delineates the measurement of CPP, was developed as the benchmark model. Given the relative nature of the productivity concept, two scenarios were considered for CPP improvement. The enhancement scenario was introduced by adding a requirement that CPP is enhanced compared with that in the benchmark model. Then a transcendence scenario was developed to ensure that CPP is better than SE. Strategies for CPP improvement were formulated and were analyzed using the analytical models developed. This study for the first time distinguished the substitutionarity and complementarity between facility occupation and facility management in the postconstruction stage, and claims that the opposite natures offer opposite strategies for CPP improvement. The empirical analysis revealed the law of diminishing marginal utility of facility management. This paper contributes to the body of knowledge by extending the productivity measurement model from the construction stage only to the integration of the construction and postconstruction stages, and by offering two productivity improvement scenarios for strategy formulation. Methodologically, this paper offers a two-stage productivity measurement model and its improvement models in a mathematical way. Managerially, based on the developed models, this work offers the evidence and quantitative guidance for the policy makers and public clients to strategically improve CPP of public projects. [ABSTRACT FROM AUTHOR]

The article discusses the structure of the mass transfer and secondary flow terms into the developed Shiono and Knight model (SKM) method aimed at clarifying the paper general concepts cited in the paper "Improved Shiono and Knight Method for Overflow Modeling." Topics addressed include the relevance of the transverse mass term, the computation of the two secondary current terms and the influence of the geometry of the compound channel and division of discrete panels.

In this paper, probabilistic models for structural analysis are put forward, with particular emphasis on model uncertainty. Context is provided by the finite-element method and the need for probabilistic prediction of structural performance in contemporary engineering. Sources of model uncertainty are identified and modeled. A Bayesian approach is suggested for the assessment of new model parameters within the element formulations. The expressions are formulated by means of numerical 'sensors' that influence the model uncertainty, such as element distortion and degree of nonlinearity. An assessment procedure is proposed to identify the sensors that are most suitable to capture model uncertainty. This paper presents the general methodology and specific implementations for a general-purpose structural element. Two numerical examples are presented to demonstrate the methodology and its implications for probabilistic prediction of structural response. [ABSTRACT FROM AUTHOR]

A review of the article "Evaluation of Explicit Numerical Solution Methods of the Muskingum Model" by Ali R. Vatankhah is presented.

The extensive irrigation systems of South Asia are predominately a hierarchy of canals delivering water to a tertiary unit. A network of field channels transfers water within the tertiary unit to the field where it is applied using surface irrigation. The network of field channels within a tertiary unit is often left to the farmers/farmer associations to construct, maintain, and operate. This paper develops a mathematical model/algorithm for routing the field channel along the existing field boundaries such that every field is serviced by a field channel and minimizing the total length of the field channel as a proxy measure of the cost of construction of field channels. The models developed in this paper are formulated as integer programs, implemented in a general-purpose solver. The model is applied to a tertiary unit of the Gomal Zam Irrigation System in Pakistan and shows that for this particular application, the optimized total length of field channels is 9,463 m compared with 11,313 m when an expert judgment is used, a reduction of 1,850 m (20%). [ABSTRACT FROM AUTHOR]

Reliability updating can improve the failure probability estimates of structural systems when new observations are obtained. At present, an efficient reliability updating method is one that transforms the equality observation information into the inequality type by introducing an auxiliary variable and then employs structural reliability methods to perform reliability updating. For this method, the computation of posterior failure probability Pr(F|Z) , where Z is an observation event, requires two reliability analysis processes to estimate Pr(Z) and Pr(F∩Z) , respectively. To improve the efficiency, this paper develops a reliability updating method with output observations, where the computation of Pr(Z) and Pr(F∩Z) is integrated into one system reliability problem, which is then solved by adaptive kriging with truncated candidate region (AKTCR). A composite adaptive learning process is developed to construct the kriging model, which can provide accurate estimates for both Pr(Z) and Pr(F∩Z). In this way, the proposed method can also deal with the problem of multiple failure modes and multiple observation events. In addition, a combined global and local sampling method is embedded into the proposed algorithm to reduce the size of candidate sample pool and improve the modeling efficiency. Finally, three examples can prove the efficiency and accuracy of the proposed reliability updating method. In this work, we present a reliability updating framework for structural systems with output observations based on kriging. Although mathematical models often replace physical systems for reliability analysis, deviation between the real physical system and its model is inevitable. Thus, it is very necessary to reevaluate the failure probability of a structural system with the available observations when its model is used. In general, these observations can be collected from various sensors, such as force sensors, accelerometers, and so on. Once observations are obtained, the likelihood function and therefore the transformed inequality limit state function can be constructed, and reliability updating can be performed. Given that many models of physical systems are still expensive, such as the finite-element model, a kriging model is adopted to replace the expensive forward model and fit the inequality limit state function for simulation. Our reliability updating framework is also applicable to cases where there are multiple failure modes and multiple observation events. We expect our reliability updating framework can significantly save computational costs in engineering practice. [ABSTRACT FROM AUTHOR]

Aeroengine fault detection is extremely significant to ensure flight safety. However, it still poses a vast challenge due to the complexity of aeroengine systems. In this paper, an unsupervised deep autoencoder (DAE) with dimension fusion function (DFF) method (DFF-DAE) was proposed to effectively detect aeroengine faults based on multivariate time-series data. The proposed method does not rely on mathematical models and expert experience to automatically extract the hierarchical representation features of raw data. The DFF-DAE has a three-layer autoencoder with its first encoding layer incorporating a DFF, which is developed for multivariate time-series fusion before encoding. A case study of aeroengine rolling bearing locking fault was conducted on the turbofan engine ground test data composed of vibration and rotational speed time-series data in variable working states. The results indicated that DFF-DAE succeeds in efficiently employing multivariate time-series data to perform accurate fault detection. Compared with other state-of-the-art methods, DFF-DAE yields superior predictive ability and detection accuracy. Furthermore, DFF-DAE provides application potential for online fault detection because it is effective in variable working states of the aeroengine. [ABSTRACT FROM AUTHOR]

The article discusses the study regarding the modeling framework for filling of water pipeline considering air phase interactions, which reference on the study titled "Modeling of Water Pipeline Events Accounting for Air Phase Interactions". Topics include the aspects of the isothermal air assumption and the estimation of air pressure, the air pocket and water impacting orifice as the criterion for the computation, and the consistency of the measured pressure.

The author discusses research on a new soil water balance model. He references the study "Interactive Irrigation Tool for Simulating Smart Irrigation Technologies in Lawn Turf" by N. A. Dobbs published in the journal in 2013. Topics covered include advances in irrigation control technologies and the role that the availability of water in the soil profile played in scheduling irrigation.

This paper compared several mathematical models predicting chloride penetration in concrete by employing a time-dependent diffusion coefficient for a number of analytical solutions of Fick's second law. We propose calibrated models that consider a time-dependent build-up of the surface chloride concentration Cs. Predicted values and measured values of chloride profiles from experimental results were compared, which showed that the calibrated models considering a time-dependent surface chloride concentration could significantly improve the correlation compared with the conventional models employing a constant surface chloride concentration. Moreover, we investigated several factors (i.e., skin effect, aging factor m , exposure conditions, curing conditions, water/binder ratio, and fly ash content) that may affect chloride penetration in concrete by adopting the calibrated models. The results showed conclusively that these factors also significantly affected the accuracy of the chloride penetration obtained by these calibrated models. Finally, the results predicted by the calibrated Tang–Gulikers model were proved to be reasonably accurate in concrete with a small water/binder ratio compared with the experimental data. It is concluded that the calibrated Tang–Gulikers model can be applied for predicting chloride penetration and solving relevant service-life problems resulting from chloride ingress in concrete. [ABSTRACT FROM AUTHOR]

Crossing culverts under highways that run through an alluvial fan is a typical converging kinematic wave flow. Design of such a crossing culvert requires the estimation of peak flow for the selected level of protection. In this paper, it was assumed that the converging kinematic wave flows on the rising hydrograph would move at the constant speed determined by the equilibrium flow depth. The derivation of the analytical solution to predict the rising hydrograph from a given converging culvert entrance is achieved. The simplified analytical solution was further compared with the numerical solutions for several case studies. It was found that the peak flow depends on the rainfall intensity, time of concentration, and location of the culvert entrance on the converging geometry. Although the rising hydrograph does not represent the complete the kinematic wave flow, it does improve the current design methods for the highway crossing culverts under highways through alluvial fans. [ABSTRACT FROM AUTHOR]

The article provides information on research and discussions on a scientific paper by scientists Oscar Castro-Orgaz and Hubert Chanson regarding minimum specific energy and Transcritical Flow in Open-Channel Flow. It presents various mathematical models including saint venant equation, backwater equation and singular point method. It also talks about Hydrostatic Modeling, Nonhydrostatic Modeling and hydraulic analysis.

Leakage may occur during pressure tests of gas pipelines. Locating the position of leakage followed by immediate repair work becomes very important. On the basis of both the theory of natural gas pipeline transportation and the procedure of pressure test, this paper established a mathematical model of leakage during pressure tests of gas pipelines. Leakage position function and discharge function, as well as the whole numerical simulation process, are studied in this paper by applying numerical inversion to partial differential equations. The theory and methods specified in this paper also can be used for leakage detection in an oil and gas pipeline's daily operation. [ABSTRACT FROM AUTHOR]

Data envelopment analysis (DEA) is a mathematical method based on production theory and the principles of linear programming. It enables one to assess how efficiently a firm, organization, agency, or such other unit uses the resources available (inputs) to generate a set of outputs relative to other units in the data set. Recent papers by different writers present different applications of DEA in the transportation engineering domain. All of these papers are published in transportation journals. These papers are mainly aimed at addressing the transportation-related issues and thus do not focus too much on the DEA concept itself. It can be asserted that DEA is very likely to be used more and more in the transportation engineering domain. Given this, there is a need for the transportation professionals to fully understand the DEA concept. It is essential for such a community to identify cases where the application of this innovative and powerful method can be useful to help the decision-making process, to accurately apply DEA in a particular setting, to derive meaningful conclusions from the obtained results, and to acknowledge the limitations of DEA in certain cases so as to approach the results with caution. The purpose of this paper is to illustrate to the civil engineering, more specifically to the transportation engineering community the use of this powerful approach in performing comparative performance measurement. Within this context, this paper will address a transportation-related problem by using the DEA approach. Different from the other papers containing transportation-related DEA applications (as mentioned above), this paper will discuss, in detail, the steps that need to be taken to generate the DEA model and solve it. [ABSTRACT FROM AUTHOR]

There are two goals in this paper: (1) the presentation of a comprehensive database of over 4,000 fundamental period and damping measurements from nearly 1,000 buildings; and (2) the derivation of predictive models for period and damping. The modeling approach presented in the companion paper, which accounts for the statistically nonconforming properties that characterize building data, is used herein to derive models which include two intrinsic sources of variability: that associated with multiple measurements from different excitations on the same building and variability between buildings that are nominally identical. The period models are in general agreement with those currently used, with model parameters that are in terms of height, material, and lateral force resisting system. The damping models show a decrease in damping as building height increases and, for steel and reinforced structures, a twofold increase in damping for earthquake excitations as opposed to other, lower amplitude excitations. [ABSTRACT FROM AUTHOR]

The article presents a closure to energy metrics for the assessment of water distribution system. Topics include a summary on how energy flows vary temporally and spatially in water distribution systems, the goal of nomenclature and energy breakdown proposed in the paper, and the convenience of bringing attention to the coincidence in the metrics.

This paper studies different specifications of fundamental diagrams for first-order dynamic traffic modeling. The fundamental diagram, which refers to the relationship between traffic flow and density at a given location, plays an important role in modeling the dynamics of traffic propagation. Many forms of fundamental diagrams have been proposed since the seminal work of Greenshields 80 years ago. Nevertheless, empirical validation of fundamental diagrams, in particular, for dynamic modeling purposes, is limited. The study is conducted with an extensive dataset collected from the U.K. M25 motorway. This paper highlights the difficulty in modeling congested traffic with single-valued fundamental diagrams and fine-grained loop detector data. Consequently, this paper first analyzes and discusses the effect of data granularity on model calibration and application. Following this, a set-valued fundamental diagram modeling approach with fine-grained data is also presented. This paper contributes to the development and validation of dynamic traffic simulation tools. [ABSTRACT FROM AUTHOR]

This paper examines the problem of determining the relation of variables and deterministic parameters of the optimum solution space for bus service zones within an urban transit model, due to the ever-evolving need for an efficient and effective transit system in modern society. A positive solution for the length of a local bus service zone was proposed and proven. Moreover, the Newton method was applied to derive a convergent sequence faster than the alternate sequence proposed in a previous paper. This analytic model will help transportation operators determine the optimum dimensions of bus service zones with great accuracy and will influence other tasks such as budget allocation. [ABSTRACT FROM AUTHOR]

To address water shortage and improve water delivery operations, decision support systems (DSSs) have been developed and utilized throughout the United States and the world. One critical aspect that is often neglected during the development and implementation of DSSs is validation, which can result in flawed water distribution and rejection of the DSS by water users and managers. This paper presents the results of a significant validation effort for a DSS in the Middle Rio Grande Conservancy District (MRGCD). The validation resulted in a refined application efficiency of 45%, a refined readily available water for farmers to irrigate to a value of 20%, and a Nash-Sutcliffe modeling efficiency of 0.86 for soil moisture depletion patterns. Overall, the validation and refinement of input parameters resulted in a DSS model that accurately predicts evaportranspiration and can be used to schedule water delivery. The refinement of the DSS input parameters resulted in an increased 15,600 acre-ft diversion suggested by the DSS, indicating that the original DSS input parameters would have adversely affected farmers in the MRGCD. The paper showed that validation of a DSS is crucial if such a program is to be successfully utilized to deliver irrigation water. [ABSTRACT FROM AUTHOR]

In this paper it was developed and tested a hydrologically based, spatially distributed crop yield model for the purpose of modeling pasture dynamics within theMediterranean environment of Marghine Goceano, in Sardinia region, Italy. The model uses daily information of weather drivers given by temperature, precipitation, and solar radiation, and provides daily spatially distributed estimates of soil water content, runoff, and pasture growth, including leaf area index (LAI) and biomass. Pasture grass growth for 6 years (2001-2006) was simulated, and yearly average biomass yield (t ha-1) was compared against ground-based and satellite-based estimates from previous studies, finding acceptable model performance. Intraseasonal biomass dynamics was evaluated during year 2004 and compared against pointwise ground measures from former studies, with acceptable results. The spatially distributed leaf area index maps were compared against their satellite-derived counterparts (9.3-km pixel size, 2005-2006), available on a biweekly basis. The pasture model provides acceptable performance in depicting daily, spatially distributed dynamics of pasture grass, and may be useful when tackling a number of issues, including, e.g., (1) assessment of pasture (and fodder) productivity under current climate and management, (2) short-term to medium-term forecast of pasture yield for seasonal herding, and (3) modified pasture conditions under prospective climate change using climate forcing from general circulation models and other climate models. Future developments may regard inclusion of nutrient dynamics and study of (over)grazing effect upon pasture dynamics. [ABSTRACT FROM AUTHOR]

Public transport travel-time variability (PTTV) is essential for understanding the deteriorations in the reliability of travel time, optimizing transit schedules, and route choices. This paper establishes the key definitions of PTTV which firstly include all buses, and secondly include only a single service from a bus route. The paper then analyzes the day-to-day distribution of public transport travel time by using transit signal priority data. A comprehensive approach, using both parametric bootstrapping Kolmogorov-Smirnov test and Bayesian information criterion technique is developed, recommends lognormal distribution as the best descriptor of bus travel time on urban corridors. The probability density function of lognormal distribution is finally used for calculating probability indicators of PTTV. The findings of this study are useful for both traffic managers and statisticians for planning and analyzing the transit systems. [ABSTRACT FROM AUTHOR]

In this paper, the difference sequence method is used to decompose traffic speed deflectometer (TSD) deflection slope measurements variability into 'true' spatial variability that is due to pavement structural changes and noise variability. A robust method to evaluate the noise standard deviation is presented and the difference sequence method is validated using simulated examples. The difference sequence method is then used to calculate the noise standard deviation and 'true' spatial variability of TSD deflection slope measurements. The evaluated noise standard deviation is also used to determine the optimal smoothing of TSD deflection slope measurements using an unbiased measure of the risk. This method is compared with the generalized cross validation (GCV) criterion to determine the optimal smoothing. Results suggest the unbiased risk criterion performs better than the GCV criterion. This gives an objective method, which is currently lacking, to average TSD measurements, and more generally any continuous deflection device measurements. Finally, the results in this paper are presented under the reproducible research paradigm; a MATLAB implementation is made available that can be downloaded and used to reproduce all figures and tables presented in this paper. [ABSTRACT FROM AUTHOR]

The article focuses on the study regarding the modeling framework for filling of water pipeline considering air phase interactions, which reference on the study titled "Modeling of Water Pipeline Events Accounting for Air Phase Interactions". Topics include concepts related to the numerical framework including air pocket pressure, discretized air-phase model, and the discrepancies between the measurement between the discretized and uniform air pressure head (UAPH) .

The author discusses the article "Comparative Case Study of Rainfall-Runoff Modeling Between SWMM and Fuzzy Logic Approach," by Keh-Han Wang et al. He notes the fuzzy logic approach presented in the paper to represent the response of a watershed and minimize the least-squares regression coefficient. He cites the current hydrological practices discussed in the work. He also asserts that the conclusions presented in the paper lack other considerations.

Theory of operations research is applied in this paper. The minimum total cost of steel reinforcement work was used as the objective function, and a three-step mathematical model to optimize the rebar cutting-stock was developed for building the finished rebars. Model I was applied to determine the whole raw material rebars that build the finished rebar. Models II and III were then applied to obtain the cut rebars needed to form the remaining rebar length of the finished rebar. The optimization results of the three-step model were combined to obtain a rebar cutting-stock list and method. Note the following results: (1) Considering comprehensively the effects of labor and material costs in the models led to the least rebar waste and number of welding spots, and thus the minimum total cost was reached. (2) In Model I, the minimum of cost sum of the rebar waste and welding spot count was taken as the objective to use the longer whole rebars first to minimize cutting and welding operations, and reducing the remaining rebar count reduced the subsequent calculation workload of Models II and III. (3) In model II, a constraint that every rebar section length be restricted to three nonoverlapping cases was imposed, which ensured that welding spots were not located in the midspan of a finished rebar. (4) In the practical case study considered, the rebar waste rate was 0.44%, and the finished rebars including 1 or 2 welding spots accounted for 90% of all finished rebars, which shows that the overall number of welding spots was small. The optimization not only clearly saved the rebar material cost but also decreased the labor cost of cutting and welding. [ABSTRACT FROM AUTHOR]

Pavement markings play an important role in the roadway system because they provide information for drivers to follow the road. Markings must be replaced when their retroreflectivity falls below an acceptable level. The rate of degradation of marking retroreflectivity can be influenced by many factors, such as type of material and traffic volume. The efficiency of pavement marking maintenance programs could be improved with statistical models that estimate the degradation of retroreflectivity over time. A case study based on data collected by the Alabama DOT was undertaken to address these issues. The purpose of the research reported in this paper was to observe how existing models fit the data and develop new statistical models that could predict retroreflectivity over time for Alabama conditions. Modeling of retroreflectivity performance over time for thermoplastic markings was executed for 15 projects that had measurements of retroreflectivity for the same locations in years 2007-2010. The modeling of retroreflectivity considered initial retroreflectivity, age, and annual average daily traffic as candidate independent variables. A linear model well-represented the data in Alabama and variable selection methods showed that initial retroreflectivity is not significant for retroreflectivity estimation. The models developed in the research reported in this paper perform better than most of the models found in the literature as shown by a comparison of correlation coefficient values. The linear model based on age and traffic volume, with correlation coefficient values of 0.448 and 0.488 for white and yellow markings, respectively, is recommended for prediction of future retroreflectivity performance and scheduling of maintenance activities. [ABSTRACT FROM AUTHOR]

A noncrossover dither creeping mutation-based genetic algorithm (CMBGA) for pipe network optimization has been developed and is analyzed in this paper. This CMBGA differs from the classic genetic algorithm (GA) optimization in that it does not utilize the crossover operator; instead, it only uses selection and a proposed dither creeping mutation operator. The creeping mutation rate in the proposed dither creeping mutation operator is randomly generated in a range throughout a GA run, rather than being set to a fixed value. In addition, the dither mutation rate is applied at an individual chromosome level rather than at the generation level. The dither creeping mutation probability is set to take values from a small range that is centered about (where = number of decision variables of the optimization problem being considered). This is motivated by the fact that a mutation probability of approximately previously has been demonstrated to be an effective value and is commonly used for the GA. Two case studies are used to investigate the effectiveness of the proposed CMBGA. An objective of this paper is to compare the performance of the proposed CMBGA with four other GA variants and other published results. The results show that the proposed CMBGA exhibits considerable improvement over the considered GA variants, and comparable performance with respect to other previously published results. Two big advantages of the CMBGA are its simplicity and the fact that it requires the tuning of fewer parameters compared with other GA variants. [ABSTRACT FROM AUTHOR]

In this paper, a simple hydrologic example is employed to illustrate the important features of reservoir regulated flood frequency. Despite its practical significance, the estimation of reservoir regulated flood frequency is largely dominated by empirical methodologies containing assumptions that could lead to incorrect results. The goal of this paper is to show by means of a continuous rainfall-runoff simulation how several reservoir variables, including the reservoir storage capacity, the size of release structures, operation rules, and the statistical variability of inflows to the reservoir, quantitatively control the regulated flood frequency. Although the example presented in this paper does not encompass the full complexity of the problem, it reveals important features of the regulated flood frequency. The study also highlights how specific assumptions in the traditional and widely used inflow volume-duration-frequency (VDF)-based methodology could lead to underestimation of flood risk for locations downstream from reservoirs. This paper, therefore, provides insight into the steps necessary to move away from the VDF-based empirical analysis towards a more realistic framework for estimating regulated flood frequencies. Simultaneously, the difficulties in fully addressing this problem are acknowledged and, consequently, continued examination of this important subject by the hydrological-science and engineering community is advocated. [ABSTRACT FROM AUTHOR]

This paper studies a repetitive project scheduling problem considering multiple crews and fixed logic with the objective to minimize the total cost without exceeding a given deadline. Multiple crews means that an activity can be performed simultaneously in several units by hiring additional crews, whereas fixed logic indicates that for each activity the units assigned to the same crew must be performed by a fixed construction sequence. Existing research works use heuristic methods to solve the problem without formulating an explicit model for further analysis. In this paper, we adopt the mixed-integer programming approach to construct an exact model. To handle large-size problems, an approximate model with reduced number of constraints and variables is further presented. Extensive computational experiments demonstrate that the exact model is capable of finding optimal solutions for medium-size problems in a reasonable amount of time, and the approximate model produces good feasible solutions for large-size problems in an accepted length of time. [ABSTRACT FROM AUTHOR]

The objective of this paper is to provide details of the design and response of a full-scale cold-formed steel (CFS)-framed building that was tested under a series of dynamic excitations during different phases of construction. The seismic response of complete buildings framed from CFS is essentially unexplored, although significant work on the behavior of CFS members and subsystems, particularly shear walls has been conducted. The experiments described herein are the first tests of a CFS-framed building designed to North American seismic standards. Seismic testing was conducted using the twin shake tables at the University at Buffalo through the U.S. National Science Foundation Network for Earthquake Engineering Simulation program. The project was conducted in two phases. In the first phase, the building specimen was constructed and tested with only the structural components in place: CFS shear walls sheathed with oriented strand board (OSB), CFS gravity walls (unsheathed), and CFS-framed floor and roof diaphragms sheathed with OSB. Nondestructive testing and design basis earthquake-level testing were performed in this phase. In the second phase, a second building specimen was constructed, to identical specifications as in the first phase. However, the second building specimen was finished with nonstructural components including exterior sheathing of the perimeter gravity walls, gypsum-board sheathing of the interior of the perimeter gravity and shear walls, interior partition walls, ceilings, staircases, and exterior weatherproofing. Nondestructive testing was conducted at construction milestones, and the finished second-phase specimen was destructively tested at the maximum considered earthquake level. This paper presents the fundamental system-level response of these building specimens: period, percent damping, drift, and accelerations. The companion paper details component-level response. Overall, the work demonstrates the excellent performance of these structures under seismic excitation, while highlighting that this performance is related to the full system-level response and not just the designated elements in the lateral-force-resisting system. [ABSTRACT FROM AUTHOR]

For fast-growing cities in developing countries, population distribution is significantly affected by a candidate rail transit line. To enjoy the travel convenience of rail service, households would like to move into residential locations in the candidate rail transportation corridor. Meanwhile, while more households are attracted to live in the candidate rail transportation corridor over years, the over-year performance of the candidate rail transit line would be better. That is, interaction exists between population distribution and performance of the candidate rail transit line over years. Unfortunately, the over-year interaction between population distribution and performance of the candidate rail transit line was seldom considered in previous studies. This paper tries to bridge this research gap and presents analytical forecasting of population distributions over years in a new candidate rail transportation corridor. A bilevel mathematical model is proposed, with a lower-level problem formulated as a user-equilibrium model, and an upper-level problem formulated as an over-year rail transit line design model. Finally, a numerical example is given to show the application of the proposed model. [ABSTRACT FROM AUTHOR]

The mechanical properties of viscoelastic (VE) dampers directly affect the aseismic performance of viscoelastically damped structures; therefore, it is of great significance to accurately describe the nonlinear mechanical characteristics of VE dampers in the aseismic design and analysis of structures. However, most of the existing mathematical models for VE dampers have been established from a macroscopic perspective, and there is a general lack of a comprehensive connection to the microstructure characteristics of VE materials and external influence factors such as loading frequency, ambient temperature, and strain amplitude. In this paper, inspired by the molecular chain network models and fractional derivative theory, a microstructure-based equivalent visco-hyperelastic model is proposed for VE dampers with consideration of temperature dependence and the filler reinforcement effect. To verify the characterization capacity of the proposed model, laboratory experiments on the dynamic property of VE dampers were carried out with varying frequencies, temperatures, and strain amplitudes, and the proposed model was then employed to predict the experimental results. Finally, model parameter analysis was conducted to clarify the relationship between material microstructure and its macroscopic performance. The experiments indicate that the VE damper possesses an excellent energy-dissipation capability, and characteristic parameters of VE dampers tend to be more sensitive in the low ranges of frequency and temperature than in the high ranges. Comparisons between the experimental and numerical results suggest that the proposed model can describe the mechanical properties of VE dampers at different frequencies, temperatures, and strain amplitudes with good accuracy. Parameter analysis demonstrates that the proposed model can reflect the influence of material microstructure on the macroscopic mechanical properties of VE dampers. [ABSTRACT FROM AUTHOR]

With the increasing number of aging bridges that need maintenance and rehabilitation (M&R), it is important to plan and prioritize M&R projects proactively. This process requires mathematical models capable of predicting bridge condition over multiyear planning horizons taking into account the long-term performance effects of M&R treatments. This paper describes the development, validation, and application of Markov chain–based bridge deterioration prediction models. Bridge condition is measured in terms of the National Bridge Inventory (NBI) deck rating, superstructure rating, substructure rating, and culvert rating. The models consider explanatory variables that affect bridge deterioration, including climate/environment, traffic loading, material type, and M&R type. Because data on M&R work history are often disconnected from bridge condition data, the study used a novel approach that allows for inferring past M&R type and timing based on changes in bridge condition ratings. The models were developed using condition data for 43,320 bridges across Texas extending from 2001 to 2017. The developed prediction models can be used as a tool to support bridge asset management planning in Texas. The modeling approach, however, can be used by transportation agencies across the world to develop bridge deterioration prediction models using their local empirical data. [ABSTRACT FROM AUTHOR]

In this paper, the friction generated in gas-flow regulation of ducted rockets is considered, and a compensation method is discussed to eliminate its effect. First, the dynamic mathematic model of gas flow-regulating system considering friction is established and analyzed. Then, the mechanism of friction-compensation method based on additional dither signal is proposed, and the compensation loop with adaptive-amplitude dither signal is added to the original system to overcome the effect of the varied friction. The simulation results show the validation of the adaptive dither signal in solving the problems caused by the variable friction in gas-regulation system of ducted rockets. [ABSTRACT FROM AUTHOR]

This paper summarizes a mathematical model that relates the geometric and geotechnical features of a road construction site with the allocation of materials, searching for a minimum construction cost. This paper proposes a linear programming model to optimize excavation and paving services. With this model, it is possible to evaluate site alternatives with different soil strata and different degrees of compaction. The borrow pit materials are allocated in the most economical way, and it is possible to incorporate more inputs like materials mix. Software was used to solve the model, and a spreadsheet application was used as an interface for data input. The proposed model demonstrated possible cost savings in earthwork planning. It is expected that earthwork and paving optimization with linear programming will reduce road construction costs considerably. [ABSTRACT FROM AUTHOR]

Strengthening of RC columns through lateral confinement using fiber-reinforced polymer (FRP) jackets is now a widely accepted technique. While extensive research has been conducted on the behavior of such strengthened columns, only a very limited amount of work has examined the slenderness effect in these columns. To correct this deficiency, this paper presents a systematic study on the subject and proposes the first ever design method for slender FRP-confined circular RC columns. A simple theoretical column model for such columns is first described in the paper. Numerical results obtained from this theoretical model are then presented to examine the behavior of these columns to identify the key parameters of influence. A design method based on numerical results from the column model and following the nominal curvature approach is next formulated. The accuracy and safety of the proposed design method is demonstrated through comparison with existing experimental results. [ABSTRACT FROM AUTHOR]

This paper focuses on the development of simplified mathematical models of the cryosphere which may be useful in further understanding possible global climate change impacts and in further assessing future impacts captured by global circulation models (GCMs). The mathematical models developed by leveraging the dominating effects of freezing and thawing within the cryosphere to simplify the relevant heat transport equations are tractable to direct solution or numerical modeling. In this paper, the heat forcing function is assumed to be a linear transformation of temperature (assumed to be represented by proxy realizations). The output from the governing mathematical model is total ice volume of the cryosphere. The basic mathematical model provides information as a systems modeling approach that includes sufficient detail to explain ice volume given the estimation of the heat forcing function. A comparison between modeling results in the estimation of ice volume versus ice volume estimates developed from use of proxy data are shown in the demonstration problems presented. [ABSTRACT FROM AUTHOR]