Academic literature on the topic 'Coast changes – Mathematical models'
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Journal articles on the topic "Coast changes – Mathematical models"
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Montoya, Germán A., and Yezid Donoso. "Delay-Sensitive Optimization Models and Distributed Routing Algorithms for Mobile Wireless Sensor Networks." International Journal of Computers Communications & Control 11, no. 6 (October 17, 2016): 819. http://dx.doi.org/10.15837/ijccc.2016.6.2745.
Full textAbstract:
Communication disruptions caused by mobility in wireless sensor networks introduce undesired delays which affect the network performance in delay sensitive applications in MWSN. In order to study the negative effects caused by mobility, we propose two mathematical models to find the minimum cost path between a source node and a destination node considering the nodes position changes across time. Our mathematical models consider the usage of buffers in the nodes to represent the fact of storing a message if there is not an appropriate forwarding node for transmitting it. In order to contrast our mathematical models results we have designed two kinds of algorithms: the first one takes advantage of the closest neighbours to the destination node in order to reach it as fast as possible from the source node. The second one simply reaches the destination node if a neighbour node is precisely the destination node. Finally, we compare the delay performance of these algorithms against our mathematical models to show how efficient they are for reaching a destination node. This paper is an extension of [10].a The mathematical model proposed in [10] is improved by adding two new binary variables with the aim of make it more readable and compact mathematically. This means a post-processing algorithm is added only for evaluating if a solution is at the first network state.
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Head, R., D. Shepherd, G. Butt, and G. Buck. "OTTER mathematical process simulation of potable water treatment." Water Supply 2, no. 1 (January 1, 2002): 95–101. http://dx.doi.org/10.2166/ws.2002.0012.
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Process modelling has been used for many years in the chemical engineering field and more recently has become well established for as a tool for analysing and optimising the performance of wastewater treatment works. In the clean water area, models are routinely used for simulating distribution networks. In contrast, however, the use of modelling tools on potable water treatment works is relatively new and has yet to become well established. A range of tools have been suggested, including artificial neural networks, computational fluid dynamics and process simulation. WRc have developed a dynamic simulation package for predicting the performance of water treatment works, via models of individual processes. The software has a range of uses, including process and works optimisation, operational decision support, as a design aid and for training engineers and operators. The models are dynamic so that they predict the response of the treatment works to changes in flow, raw water quality and process operating conditions. The software has been used in a wide variety of applications, including optimising process plant operation to minimise cost and to investigate the reasons why a treatment works failed to meet its design criteria at the maximum design throughput.
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CHANG, HORNG-JINH, and WEN-FENG LIN. "A SIMPLE SOLUTION METHOD FOR THE FINITE HORIZON EOQ MODEL FOR DETERIORATING ITEMS WITH COST CHANGES." Asia-Pacific Journal of Operational Research 28, no. 06 (December 2011): 689–704. http://dx.doi.org/10.1142/s0217595911003314.
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In this article, we generalize Lev and Weiss's (1990) finite horizon economic order quantity (EOQ) model with cost change to the inventory system with deterioration. Supplier announces some or all of cost parameters may change after a decided time. Depending on whether the inventory is depleted at the time of the last opportunity to purchase before some or all of the cost parameters may change, there are two types of inventory models to be discussed. The main objective of this paper is to identify the optimal ordering policy of the inventory system by comparing the minimum cost of the two types of models. We suggest a finite horizon EOQ model to combine the above two types and propose a theorem that can quickly identify the optimal policy of the suggested model. In considering temporary price discount problem and discrete-time EOQ problem, in general, there are integer operators in mathematical models, but our approach offers a closed-form solution to these kinds of problems. Numerical examples are presented to demonstrate the results of the proposed properties and theorem.
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Pourbakhshian, Somayyeh, and Majid Pouraminian. "Analytical Models for Optimal Design of a Trapezoidal Composite Channel Cross-Section." Civil and Environmental Engineering Reports 31, no. 1 (March 1, 2021): 118–38. http://dx.doi.org/10.2478/ceer-2021-0009.
Full textAbstract:
Abstract In this paper, several analytical models are presented for the optimal design of a trapezoidal composite channel cross-section. The objective function is the cost function per unit length of the channel, which includes the excavation and lining costs. To define the system, design variables including channel depth, channel width, side slopes, freeboard, and roughness coefficients were used. The constraints include Manning’s equation, flow velocity, Froude number, and water surface width. The Simultaneous Perturbation Stochastic Approximation (SPSA) algorithm was used to solve the optimization problem. The results are presented in three parts; in the first part, the optimal values of the design variables and the objective function are presented in different discharges. In the second part, the relationship between cost and design variables in different discharges is presented in the form of conceptual and analytical models and mathematical functions. Finally, in the third part, the changes in the design variables and cost function are presented as a graph based on the discharge variations. Results indicate that the cost increases with increasing water depth, left side slope, equivalent roughness coefficient, and freeboard.
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Fang, Y., M. Huang, C. Liu, H. Y. Li, and L. R. Leung. "A generic biogeochemical module for earth system models." Geoscientific Model Development Discussions 6, no. 2 (June 13, 2013): 3211–40. http://dx.doi.org/10.5194/gmdd-6-3211-2013.
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Abstract. Physical and biogeochemical processes regulate soil carbon dynamics and CO2 flux to and from the atmosphere, influencing global climate changes. Integration of these processes into earth system models (e.g. community land models – CLM), however, currently faces three major challenges: (1) extensive efforts are required to modify modeling structures and to rewrite computer programs to incorporate new or updated processes as new knowledge is being generated, (2) computational cost is prohibitively expensive to simulate biogeochemical processes in land models due to large variations in the rates of biogeochemical processes, and (3) various mathematical representations of biogeochemical processes exist to incorporate different aspects of fundamental mechanisms, but systematic evaluation of the different mathematical representations is difficult, if not impossible. To address these challenges, we propose a new computational framework to easily incorporate physical and biogeochemical processes into land models. The new framework consists of a new biogeochemical module with a generic algorithm and reaction database so that new and updated processes can be incorporated into land models without the need to manually set up the ordinary differential equations to be solved numerically. The reaction database consists of processes of nutrient flow through the terrestrial ecosystems in plants, litter and soil. This framework facilitates effective comparison studies of biogeochemical cycles in an ecosystem using different conceptual models under the same land modeling framework. The approach was first implemented in CLM and benchmarked against simulations from the original CLM-CN code. A case study was then provided to demonstrate the advantages of using the new approach to incorporate a phosphorus cycle into the CLM model. To our knowledge, the phosphorus-incorporated CLM is a new model that can be used to simulate phosphorus limitation on the productivity of terrestrial ecosystems.
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Trad, Antoine. "An Applied Mathematical Model for Business Transformation and Enterprise Architecture." International Journal of Organizational and Collective Intelligence 11, no. 1 (January 2021): 1–25. http://dx.doi.org/10.4018/ijoci.2021010101.
Full textAbstract:
To restructure or transform a business organization in the optimal manner, there is a need for a specific organizational intelligence and engineering pattern to support a business transformation and integration strategy. The applied strategy should be based on existing standards, mapping concepts, and various levels of interoperability. Today, many standards, patterns, and methodologies exist, and they are very advanced and are able to support the organizational transformation process of the older business environment to become part of a larger business eco-system. Transforming a traditional organization or a business environment into an innovative and efficient organization based atomic service-oriented environment is a great challenge, because transformation initiatives often fail, mainly because of the monolithic nature of the mammoth-like organisations. Many monolithic environments and their correspondent business information and communication systems fail to be transformed and are unable to adapt to the new business requirements and challenges. These presented facts make organizations unable to follow frequent changes and this fact might cost organizations fortunes without obtaining the return on investment. A well-designed organizational transformation process and a reorganized business environment should be based on a platform of flexible atomic business loose block (or microartefacts) that can support the future changes request of the business environment. In order to reach the optimal organizational transformation models, an organizational engineering pattern must be designed to improve the functions of the existing business services. This article's goal is to present an organizational engineering and risk pattern integration concept is presented to support frequent change initiatives.
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ROMANCHENKO, Ihor S., Oleh SEMENENKO, Maryna SLIUSARENKO, Mykola VASIANOVYCH, and Ihor LEVCHENKO. "On the development of mathematical models for the reliability evaluation of aircraft operation in combat conditions." INCAS BULLETIN 13, S (August 3, 2021): 169–78. http://dx.doi.org/10.13111/2066-8201.2021.13.s.16.
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The authors of this study propose a methodological approach to modelling the reliability evaluation of aircraft operation in combat conditions. When developing recommendations on operational and strategic requirements for promising aircraft, a very important aspect is the elicitation of the requirements for their reliability, namely no-failure operation. Reliability as a parameter of any equipment should be set in the technical specifications for development together with other operational requirements in the form of reasonable quantitative indicators – reliability standards. The establishment of specific reliability standards stimulates its growth and creates the basis for rational design, taking into account the requirements of reliable operation. The analysis showed that different models can be used to simulate aircraft reliability. In this case, for example, the final values of mean time to failure (MTTF) would be different. The test results show that the methods and mathematical models used to substantiate the values of time and probability of trouble-free operation of aircraft do not fully correspond to the actual processes of changing their state during the use in the military. This is confirmed by a significant discrepancy in the values of reliability indicators implemented in practice. This was due to the fact that the acquainted mathematical models of aircraft reliability do not take into account the combat conditions in which they are supposed to operate. In addition, the reliability indicators used do not take into account possible changes (decrease) in these indicators during the period of aircraft operation. In general, the shortcomings inherent in the methods and mathematical models currently used to describe the aircraft reliability reduce the accuracy of the results obtained, and also do not quite adequately reflect the features of the corresponding process. When using different models, the cost of time to failure differs significantly. The more factors are taken into account, the greater the operating time to failure will be. This means that when designing aircraft, it is necessary to set the value of this indicator greater than indicated in the form. Taking into account additional factors complicates the model, but at the same time makes it more accurate.
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Kuz’min, A. Yu. "An Accounting Procedure for Bonds with a Double Currency Denomination in Accordance with the IFRS." Accounting. Analysis. Auditing 7, no. 6 (December 19, 2020): 55–63. http://dx.doi.org/10.26794/2408-9303-2020-7-6-55-63.
Full textAbstract:
The study is devoted to the development of accounting procedure and recording the financial results of bonds with a double currency denomination in accordance with International Financial Reporting standards (IFRS). The methodological base of the research includes system and dynamic-situational analysis, evaluation models of financial mathematics, accounting procedures of the theory of financial accounting. Based on the assumptions made at the formal mathematical level, this procedure is fully algorithmized, despite the ambiguity or impossibility of direct assessment of such basic accounting indicators as the initial estimate, the internal effective interest rate, and the amortized cost of a financial instrument. Considerable attention is paid to the issues of mathematical evaluation and reflection of financial results when preparing financial statements in accordance with the concept of amortized cost and effective interest rate, taking into account the impact of changes in the currency component in dynamics. The originality and uniqueness of the developed procedure is that it is applicable to the situations where coupon payments are paid several times a year. The theoretical and practical significance of the research is determined by the development of scientific and applied tools that include accounting and process models, evaluation algorithms and procedures that can be used by accounting and audit departments in practical work when solving problems of reporting in accordance with IFRS.
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Rocher, Javier, Mar Parra, Lorena Parra, Sandra Sendra, Jaime Lloret, and Jesús Mengual. "A Low-Cost Sensor for Detecting Illicit Discharge in Sewerage." Journal of Sensors 2021 (March 10, 2021): 1–16. http://dx.doi.org/10.1155/2021/6650157.
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The presence of illicit discharges in sewerage systems generates an important impact in wastewater treatment plants and the ecosystem. In this paper, we present two prototypes for monitoring the presence of solids in wastewater and to study the effect of the water height. The prototypes are based on color and infrared LEDs and two photosensors located in the prototypes at 0° and 180° degrees. When the photosensor is located at 180°, all color LEDs present a good range of output voltage (approximately 5 V to 0 V) and good R2. However, for the typical concentration of solids in wastewater, the prototypes do not work correctly. When the photosensor is located in the prototypes the LEDs, yellow, red, and white have a good operation with voltage differences of 1.73 V, 1.76 V, and 1.13 V in P1 and 1.58 V, 1.84 V, and 1.35 V in P2, respectively. We calculate the mathematical model with the heights and solid concentration. The mathematical models which do not consider height present good R2. In conclusion, when the photosensor is located in the prototype, the height does not have an important effect and can detect the illicit discharge of solids. When the photosensor is located at 180°, it can be used for water with important changes in solid concentrations.
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Fang, Y., M. Huang, C. Liu, H. Li, and L. R. Leung. "A generic biogeochemical module for Earth system models: Next Generation BioGeoChemical Module (NGBGC), version 1.0." Geoscientific Model Development 6, no. 6 (November 13, 2013): 1977–88. http://dx.doi.org/10.5194/gmd-6-1977-2013.
Full textAbstract:
Abstract. Physical and biogeochemical processes regulate soil carbon dynamics and CO2 flux to and from the atmosphere, influencing global climate changes. Integration of these processes into Earth system models (e.g., community land models (CLMs)), however, currently faces three major challenges: (1) extensive efforts are required to modify modeling structures and to rewrite computer programs to incorporate new or updated processes as new knowledge is being generated, (2) computational cost is prohibitively expensive to simulate biogeochemical processes in land models due to large variations in the rates of biogeochemical processes, and (3) various mathematical representations of biogeochemical processes exist to incorporate different aspects of fundamental mechanisms, but systematic evaluation of the different mathematical representations is difficult, if not impossible. To address these challenges, we propose a new computational framework to easily incorporate physical and biogeochemical processes into land models. The new framework consists of a new biogeochemical module, Next Generation BioGeoChemical Module (NGBGC), version 1.0, with a generic algorithm and reaction database so that new and updated processes can be incorporated into land models without the need to manually set up the ordinary differential equations to be solved numerically. The reaction database consists of processes of nutrient flow through the terrestrial ecosystems in plants, litter, and soil. This framework facilitates effective comparison studies of biogeochemical cycles in an ecosystem using different conceptual models under the same land modeling framework. The approach was first implemented in CLM and benchmarked against simulations from the original CLM-CN code. A case study was then provided to demonstrate the advantages of using the new approach to incorporate a phosphorus cycle into CLM. To our knowledge, the phosphorus-incorporated CLM is a new model that can be used to simulate phosphorus limitation on the productivity of terrestrial ecosystems. The method presented here could in theory be applied to simulate biogeochemical cycles in other Earth system models.
Dissertations / Theses on the topic "Coast changes – Mathematical models"
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Dang, Van To Civil & Environmental Engineering Faculty of Engineering UNSW. "Development of a mathematical N-line model for simulation of beach changes." Awarded by:University of New South Wales. School of Civil and Environmental Engineering, 2006. http://handle.unsw.edu.au/1959.4/27394.
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The development of a new N-Line model, which provides a practical tool for simulating regional beach changes induced by short and long-term processes, is described in this thesis. The new N-Line model consists of four main modules that together describe the hydrodynamic and morphological responses. The four constituent modules have been integrated based on a wide range of research including the utility and function of commercial or freeware models. They are RCPWAVE wave module, time-averaged and depth-integrated current module, sediment transport module based on Bailard (1981) and contour change morphological module. Two different time-scales and two staggered grid systems for hydrodynamic and morphological simulations were adopted alternatively. For short-term 2D profile changes, new N-Line model applicability has been examined using data from the laboratory to the field. For ideal beaches, new N-Line can simulate an offshore storm bar generation or an onshore accretion due to high or low energy waves. For SUPERTANK large-scale flume data, the predicted profile matched the measured profile well, especially the bar height and position. For beach profile data from the Gold Coast, storm-induced variations of barred profiles were reasonably modelled. The new N-Line model compared well with other commonly used cross-shore models such as SBEACH and UNIBEST. A new schematisation for a non-monotonic profile and DUNED inclusion were introduced. Sensitivity tests on cross-shore sediment coefficient (Kq), smoothing parameter (??s) and water level fluctuations were performed. For long-term 3D beach changes, the new N-Line model applicability has been tested with various boundary conditions using idealized and real field data. Two periods, 17 and 16 months, of beach changes before and after a major bypass plant commenced operation in 2001 at Letitia Spit were simulated. The profile and shoreline changes were predicted reasonably well. Empirical model parameters were determined after a range of sensitivity and calibration testing. The new N-Line model showed its better performance compared to one-line models. It can handle various boundary conditions, especially bypass conditions. The N-Line model is not only capable of modelling planform variations but also cross-shore profile changes.
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Peterson, Erica Kay. "An Econometric Analysis of Cost Changes in U.S. Trucking and the Implications of Implementing the NAFTA Trucking Provisions." Thesis, North Dakota State University, 2007. https://hdl.handle.net/10365/29800.
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The United States trucking industry underwent deregulation starting in 1980. There was much opposition to the process in fears that trucking companies would be adversely affected by increased competition. There were also many proponents and researchers who proved that the increased competition due to regulatory reform only helped strengthen the industry by forcing firms to become more cost efficient. There has been similar opposition and support for the trucking provisions of NAFTA. Although the provisions have not been fully implemented, the trucking industry is well aware it will only be a matter of time. In early 2002 it was announced that the process to begin implementing the trucking provisions would begin in mid-2002. Many in the industry and other groups have opposed implementing the
provisions, concerned that U.S. trucking firms would be subject to competition from Mexican firms, just as they feared trucking firms would be adversely affected by deregulation more than 25 years ago. This thesis analyzes the effects the 2002 announcement of the process to begin implementing the trucking provisions has had on the cost structure of the industry. It uses a translog cost function to determine if firms have become more efficient in the years following the announcement in anticipation of increased competition from Mexican firms after the provisions are fully implemented. The translog cost function is used to determine what effects the NAFTA variable has had on costs and what specific operating characteristics have caused the costs to increase or decrease.
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Demir, Huseyin. "A Process-Based Model for Beach Profile Evolution." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19811.
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Beach profile models predict the changes in bathymetry along a line perpendicular to the shoreline. These models are used to forecast bathymetric changes in response to storms, sea level rise or human activities such as dredging and beach nourishment. Process-based models achieve this by simulating the physical processes that drive the sediment transport as opposed to behavior models which simulate observed profile changes without resolving the underlying processes. Some of these processes are wave shoaling and breaking, boundary layer streaming, and offshore-directed undertow currents. These hydrodynamic processes control the sediment processes such as sediment pick-up from the bottom, diffusion of the sediment across the water column and its advection with waves and currents.
For this study, newly developed sediment transport and boundary layer models were coupled with existing models of wave transformation, nearshore circulation and bathymetry update, to predict beach profile changes. The models covered the region from the dry land to a depth of 6-8 meters, spanning up to 500 meters in the cross-shore direction. The modeling system was applied at storm time scales, extending from a couple of hours to several days. Two field experiments were conducted at Myrtle Beach, SC, involving the collection of wave, current and bathymetric data as a part of this study. The results were used to calibrate and test the numerical models along with data from various laboratory studies from the literature.
The sediment transport model computes the variation of sediment concentrations over a wave period and over the water column, solving the advection-diffusion equation using the Crank-Nicholson finite-difference numerical scheme. Using a new approach, erosion depth thickness and sediment concentrations within the bed were also predicted. The model could predict sediment transport rates for a range of conditions, within a factor of two. It successfully computed the sediment concentration profile over the water column and within the bed and its variation throughout a wave period. Erosion depth and sheet flow layer thickness were also predicted reasonably well.
Wave heights across the profile were predicted within ten percent when the empirical wave breaking parameter was tuned appropriately. Mean cross-shore velocities contain more uncertainty, even after tuning. The importance of capturing the location of the maximum, near-bottom, cross-shore velocity when predicting bar behavior was shown. Bar formation, erosion, accretion, onshore and offshore bar movement were all computed with the model successfully
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Ng, Max Kin-Fat. "Assessment of tsunami hazards on the British Columbia coast due to a local megathrust subduction earthquake." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29633.
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Strong evidence suggests that the Cascadia subduction zone, off the west coast of Canada and the United States, is strongly seismically-coupled and that a possible
megathrust earthquake might occur in that area in the near future. A study of tsunami hazards along the Canadian west coast associated with such a hypothetical earthquake is presented in this report. Numerical simulations of tsunami generation and propagation have been carried out using three models based on shallow water wave theory.
Three cases of ground motion representing the ruptures of different crustal segments
in the area have been examined. Computed results provide information on tsunami arrival times and a general view of the wave height distribution. The outer coast of Vancouver Island was found to be the most strongly affected area. At the head of Alberni Inlet, wave amplitudes reached up to three times the source magnitude.
Inside the Strait of Georgia, the wave heights are significant enough to receive closer attention, especially in low-lying areas.Science, Faculty of
Physics and Astronomy, Department of
Graduate
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Johnston, Susan Joy. "The development of an operational management procedure for the South African west coast rock lobster fishery." Doctoral thesis, University of Cape Town, 1998. http://hdl.handle.net/11427/22567.
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This thesis considers the development of an operational management procedure (OMP) to provide scientific recommendations for commercial TAC for the South African west coast rock lobster (Jasus lalandii) fishery. This fishery has been under considerable stress in recent years as a result of overfishing and low somatic growth rates. Present catch levels, less than 2000 MT, are substantially smaller than levels recorded in the past. The present biomass (above 75mm carapace length) is estimated to be only six percent of the pristine level. At the start of this research, no long-term management strategy for the resource existed. Neither was there any robust, tested, scientific method available for setting the annual TAC for the fishery, which resulted in a time-consuming and unsatisfactory scientific debate each year in developing a series of ad hoc TAC recommendations. The work presented in this thesis is thus aimed at answering two important questions. i) Can an adequate mathematical model be developed as a basis to simulate the resource and its associated fishery? ii) Can a self-correcting robust OMP be developed for the resource? The first phase of this thesis is the development of a size-structured population model of the resource and the associated fishery. A size-structured model is necessary as lobsters are difficult to age and hence most of the data collected are on a size basis. Furthermore, important management issues, such as the legal minimum size which has changed over time, require a model able to take size-structure into account. This model is fitted to a wide range of data from the fishery, including CPUE (catch-per-unit-effort) and catch-at-size information, by maximising a likelihood function. The model is shown to fit reasonably well to all data, and to provide biologically plausible estimates for its six estimable parameters.
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Coulombe, Daniel. "Voluntary income increasing accounting changes : theory and further empirical investigation." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26983.
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This thesis presents a three step analysis of voluntary income increasing accounting changes. We first propose a theory as to why managers would elect to modify their reporting strategy. This theory builds on research on the economic factors motivating accounting choices, since it is assumed that accounting choices are a function of political costs, manager's compensation plans and debt constraints. Specifically, we claim that adversity motivates the manager to effect an income increasing accounting change.
Secondly, the thesis proposes a theoretical analysis of the potential market responses to a change announcement. The stock price effect of a change announcement is examined as a function of investors' rational anticipations of the manager's reporting actions and as a function of the level of information about adversity that investors may have prior to a change announcement.
An empirical analysis is presented in the third step of this thesis. Our empirical findings are that:
1- Change announcements, on average, have no significant impact on the market.
2- Relative to the Compustat population as a whole, firms that voluntarily adopt income increasing accounting changes exhibit symptoms of financial distress, suggesting that such change announcements are associated with financial adversity.
3- Firms which voluntarily adopt income increasing accounting changes tend to exhibit symptoms of financial distress one or more years prior to the change year, suggesting that change announcements tend not to be a timely source of information conveying distress to the market.
4- There is a significant negative association between investors' proxies for prior information about adversity and the market impact of the change, especially for the subset of firms with above average leverage, suggesting that the information content of the accounting change signal is inversely related to investors prior information about adversity.
The empirical results thus support the view that investors, at the time a change occurs, have information about the prevailing state of the world, and that they have rational anticipations with respect to the manager's reporting behavior. In this respect, the accounting change is, on average, an inconsequential signal that adds little to what investors already knew before the change announcement.Business, Sauder School of
Graduate
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Andrews, Rick L. "Temporal changes in marketing mix effectiveness." Diss., This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-07282008-134759/.
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Santoso, Agus Mathematics & Statistics Faculty of Science UNSW. "Evolution of climate anomalies and variability of Southern Ocean water masses on interannual to centennial time scales." Awarded by:University of New South Wales. School of Mathematics and Statistics, 2005. http://handle.unsw.edu.au/1959.4/33355.
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In this study the natural variability of Southern Ocean water masses on interannual to centennial time scales is investigated using a long-term integration of the Commonwealth Scientic and Industrial Research Organisation (CSIRO) coupled climate model. We focus our attention on analysing the variability of Antarctic IntermediateWater (AAIW), Circumpolar DeepWater (CDW), and Antarctic Bottom Water (AABW). We present an analysis of the dominant modes of temperature and salinity (T - S) variability within these water masses. Climate signals are detected and analysed as they get transmitted into the interior from the water mass formation regions. Eastward propagating wavenumber-1, -2, and -3 signals are identied using a complex empirical orthogonal function (CEOF) analysis along the core of the AAIW layer. Variability in air-sea heat uxes and ice meltwater rates are shown by heat and salt budget analyses to control variability of Antarctic Surface Water where density surfaces associated with AAIW outcrop. The dominant mode in the CDW layer is found to exhibit an interbasin-scale of variability originating from the North Atlantic, and propagating southward into the Southern Ocean. Salinity dipole anomalies appear to propagate around the Atlantic meridional overturning circulation with the strengthening and weakening of North Atlantic Deep Water formation. In the AABW layer, T - S anomalies are shown to originate from the southwestern Weddell Sea, driven by salinity variations and convective overturning in the region. It is also demonstrated that the model exhibits spatial patterns of T - S variability for the most part consistent with limited observational record in the Southern Hemisphere. However, some observations of decadal T - S changes are found to be beyond that seen in the model in its unperturbed state. We further assess sea surface temperature (SST) variability modes in the Indian Ocean on interannual time scales in the CSIRO model and in reanalysis data. The emergence of a meridional SST dipole during years of southwest Western Australian rainfall extremes is shown to be connected to a large-scale mode of Indian Ocean climate variability. The evolution of the dipole is controlled by variations in atmospheric circulation driving anomalous latent heat uxes with wind-driven ocean transport moderating the impact of evaporation and setting the conditions favourable for the next generation phase of an opposite dipole.
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Del, Valle Sara Yemimah. "Effects of behavioral changes and mixing patterns in mathematical models for smallpox epidemics." Diss., University of Iowa, 2005. https://ir.uiowa.edu/etd/105.
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In Chapter 1, we study the effects of behavioral changes in a smallpox attack model. Response strategies to a smallpox bioterrorist attack have focused on interventions such as isolation, contact tracing, quarantine, ring vaccination, and mass vaccination. We formulate and analyze a mathematical model in which some individuals lower their daily contact activity rates once an epidemic has been identified in a community. We use computer simulations to analyze the effects of behavior change alone and in combination with other control measures. We demonstrate that the spread of the disease is highly sensitive to how rapidly people reduce their contact activity.
In Chapter 2, we study mixing patterns between age groups using social networks. The course of an epidemic through a population is determined by the interactions among individuals. To capture these elements of reality, we use the contact network simulations for the city of Portland, Oregon that were developed as part of the TRANSIMS/EpiSims project to study and identify mixing patterns. We analyze contact patterns between different age groups and identify those groups who are at higher risk of infection. We describe a new method for estimating transmission matrices that describe the mixing and the probability of transmission between the age groups. We use this matrix in a simple differential equation model for the spread of smallpox. Our differential equation model shows that the epidemic size of a smallpox outbreak could be greatly affected by the level of residual immunity in the population.
In Chapter 3, we study the effects of mixing patterns in the presence of population heterogeneity. We investigate the impact that different mixing assumptions have on the spread of a disease in an age-structured differential equation model. We use realistic, semi-bias and bias mixing matrices and investigate the impact that these mixing patterns have on epidemic outcomes when compared to random mixing. Furthermore, we investigate the impact of population heterogeneity such as differences in susceptibility and infectivity within the population for a smallpox epidemic outbreak. We find that different mixing assumptions lead to differences in disease prevalence and final epidemic size.
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Familkhalili, Ramin. "Analytical and Numerical Modeling of Long Term Changes to Tides, Storm Surge, and Total Water Level Due to Bathymetric Changes and Surge Characteristics." PDXScholar, 2019. https://pdxscholar.library.pdx.edu/open_access_etds/5014.
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Natural and local anthropogenic changes in estuaries (e.g., sea-level rise, navigation channel construction and loss of wetlands) interact with each other and produce non-linear effects. There is also a growing recognition that tides in estuaries are not stationary. These factors together are changing the estuarine water level regime, however the implications for extreme water levels remain largely unknown. Changes over the past century in many estuaries, such as channel deepening and streamlining for navigation have significantly altered the hydrodynamics of long waves, often resulting in amplified tides (a ~85% increase in Wilmington, NC since 1900) and storm surge in estuaries. This research focuses on establishing analytical and numerical models that simulate a wide range of systems and flow conditions that combine multiple flood sources: astronomical tide, storm surge, and high river flow. To investigate the effects of estuarine bathymetry conditions (e.g., channel depth, convergence length), hurricane conditions (e.g., pressure and wind field), river discharge, and surge characteristics (e.g., time scale and amplitude and relative phase) on tide and storm surge propagation, I develop an idealized analytical model and two numerical models using Delft-3D. The Cape Fear River Estuary, NC (CFRE), and St Johns River Estuary, FL (SJRE) are used as case studies to investigate flood dynamics. The analytical approach has been compared and verified with idealized numerical models.
I use data recovery, data analysis, and idealized numerical modeling of the CFRE to investigate the effects of bathymetric changes (e.g., dredging and channel modification) on tidal and storm surge characteristics over the past 130 years. Data analysis and modeling results suggest that long-term changes in tides can be used along with the tidal analysis tools to investigate changes in storm surge. Analysis indicate that tidal range in Wilmington, NC (Rkm 47) has doubled to 1.55m since the 1880s, while a much smaller increase of 0.07m observed close to the ocean in Southport (Rkm 6) since the 1920s. Further, model results suggest that the majority of long term changes in tides of this system have been caused by deepening the system from 7m to 15.5m due to dredging, rather than by changes in the coastal tides. Numerical modeling using idealized, parametric tropical cyclones suggests that the amplitude of the worst-case, CAT-5 storm surge has increased by 40-60% since the nineteenth century.
Storm surges are meteorologically forced shallow water waves with time scales that overlap those of the tidal bands. Using data, I show that the surge wave can be decomposed into two sinusoidal waves. Therefore, I analytically model surge via a 3-constituent analytical tide model, where the third constituent is the dominant semi-diurnal tide and friction is linearized via Chebyshev polynomials. A constant discharge is considered to approximate fluvial effects The analytical model is used to study how surge amplitude, surge time scale, and surge-tide relative phase affect the spatial pattern of amplitude growth and decay, and how depth changes caused by channel deepening influence the magnitude of a storm surge. I use non-dimensional numbers to investigate how channel depth, surge time scale and amplitude, surge asymmetry, and relative timing of surge to tides alter the damping or amplification of surge along the estuary. The non-dimensional numbers suggest that increasing depth has similar effects as decreasing the drag coefficient. Similarly, larger time scale has an equivalent effect on tide and surge as increasing depth due to channel deepening. Analytical model results show that the extent of the surge amplification is dependent on the geometry of the estuary (e.g., depth and convergence length) and characteristics of the surge wave. Both models show that much of the alterations of water levels in estuaries is due to channel deepening for navigation purposes and that the largest temporal change occur for surges with a high surge to D2 amplitude ratio and a short time scale. Model results farther indicate that surge amplitude decays more slowly (larger e-folding) in a deeper channel for all surge time scales (12hr-72hr). Another main finding is that, due to nonlinear friction, the location of maximum change in surge wave moves landward as the channel is deepened. Thus, changes in flood risk due to channel deepening are likely spatially variable even within a single estuary.
Next, I use the verified analytical model and numerical models to investigate the effects of river flow on surge wave propagation, and spatial and temporal variability of compound flooding along an estuary. To model the historic SJRE, I digitize nautical charts of SJRE to develop a numerical model. Both the numerical and analytical models are used to investigate the contribution of tide, surge, and river flow to the peak water level for historic and modern system configurations. Numerical modeling results for hurricane Irma (2017) show that maximum flood water levels have shifted landward over time and changed the relative importance of the various contributing factors in the SJRE. Deepening the shipping channel from 5.5m to 15m has reduced the impacts of river flow on peak water level, but increased the effects of tide and surge. Sensitivity studies also show that peak water level decreases landward for all river flow scenarios as channel depth increases. Model results show that the timing of peak river flow relative to the time of maximum surge causes very large changes in the amplitude of total water level, and in river flow effects at upstream locations for modern configuration than for the historic model. Changes in surge amplitudes can be interpreted by the non-dimensional friction number, which shows that depth (h), surge time scale (T=1/w), and convergence length-scale (Le) affect the damping/amplification of both tides and surge waves.
Overall, this study demonstrates that a system scale alteration in local storm surge dynamics over the past century is likely to have occurred in many systems and should be considered for system management. The results of this research give the scientists and engineer a better understanding of tide, river flow, and surge interactions, and thereby contribute to an understanding of how to predict storm surges and help mitigate their destructive impacts. Future system design studies also need to consider long-term and changes of construction and development activities on storm surge risk in a broader context than has historically been the case.
Books on the topic "Coast changes – Mathematical models"
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Torre, Rafael Cañizares. On the application of data assimilation in regional coastal models. Rotterdam: Balkema, 1999.
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Villaverde, José María Medina. Hidrodinámica del perfil de playa. Madrid: Colegio de Ingenieros de Caminos, Canales y Puertos, 1998.
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Hydrology, American Institute of. Coastal hydrology and processes: Proceedings of the AIH 25th Anniversary Meeting & International Conference "Challenges in Coastal Hyrology and Water Quality". Highland Ranch, CO: Water Resources Publications, 2007.
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American Institute of Hydrology. Meeting. Coastal hydrology and processes: Proceedings of the AIH 25th Anniversary Meeting & International Conference "Challenges in Coastal Hyrology and Water Quality". Highland Ranch, Colo: Water Resources Publications, 2006.
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Ad, Reniers, ed. A guide to modeling coastal morphology. Singapore: World Scientific, 2012.
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Vemulakonda, S. Rao. Kings Bay coastal processes numerical model. Vicksburg, Miss: U.S. Army Engineer Waterways Experiment Station, 1988.
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Eleveld, Marieke A. Exploring coastal morphodynamics of Ameland (the Netherlands) with remote sensing monitoring techniques and dynamic modelling in GIS. [Enschede, the Netherlands: ITC, 1999.
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Balsillie, James H. Seasonal variation in sandy beach shoreline position and beach width: And, Open-ocean water level datum planes : use and misuse in coastal applications. Tallahassee, Fla: Florida Geological Survey, Division of Resource Management, Dept. of Natural Resources, 1999.
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Modelling coastal vulnerability: Design and evaluation of a vulnerability model for tropical storms and floods. Amsterdam: IOS Press, 2009.
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Balsillie, James H. Seasonal variation in sandy beach shoreline position and beach width ; and: Open-ocean water level datum planes : use and misuse in coastal applications. Tallahassee, Fla: Florida Geological Survey, c1999., 1999.
Find full textBook chapters on the topic "Coast changes – Mathematical models"
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Blanchard, D. "Irreversible Phase Changes." In Mathematical Models for Phase Change Problems, 99–106. Basel: Birkhäuser Basel, 1989. http://dx.doi.org/10.1007/978-3-0348-9148-6_6.
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Battaglia, Francesco, Domenico Cucina, and Manuel Rizzo. "Periodic Autoregressive Models with Multiple Structural Changes by Genetic Algorithms." In Mathematical and Statistical Methods for Actuarial Sciences and Finance, 107–10. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-89824-7_19.
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Cermelli, Paolo, Giuliana Indelicato, and Reidun Twarock. "The Role of Symmetry in Conformational Changes of Viral Capsids: A Mathematical Approach." In Discrete and Topological Models in Molecular Biology, 217–40. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-40193-0_10.
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Sachs, Mendel. "Changes in Concepts of Time from Aristotle to Einstein." In Modern Mathematical Models of Time and their Applications to Physics and Cosmology, 269–81. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-011-5628-8_23.
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Krolzig, Hans-Martin. "In the last decade time series econometrics has changed dramatically. One increasingly prominent field has become the treatment of regime shifts and non-linear mod- elling strategies. While the importance ofregime shifts, particularly in macroeconometric systems, seems to be generally accepted, there is no established theory suggesting a unique approach for specifying econometric models that embed changes in regime." In Lecture Notes in Economics and Mathematical Systems, 1–5. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-51684-9_1.
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Verma, Vibha, Neha Neha, and Anu G. Aggarwal. "Software Release Planning Using Grey Wolf Optimizer." In Advances in Systems Analysis, Software Engineering, and High Performance Computing, 1–44. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-1718-5.ch001.
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This chapter presents the application of grey wolf optimizer in software release planning considering warranty based on the proposed mathematical model that measures reliability growth of software systems. Hence, optimal release and warranty time is determined while minimizing the overall software development cost. The software cost model is based on failure phenomenon modelled by incorporating fault removal efficiency, fault reduction factor, and error generation. The model has been validated on the fault dataset of ERP systems. Sensitivity analysis has been carried out to study the discrete changes in the cost parameter due to changes in optimal solution. The work significantly contributes to the literature by fulfilling gaps of reliability growth models, release problems considering warranty, and efficient ways for solving optimization problems. Further, the grey wolf optimizer result has been compared with genetic algorithm and particle swarm optimization techniques.
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Valentina, Florea Nicoleta. "Procurement Process and Supply Chain." In Handbook of Research on Industrial Applications for Improved Supply Chain Performance, 226–61. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-0202-0.ch010.
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Organizations are operating in an environment which offers opportunities but also dangers, risks, changes, and challenges. To face these changes, organizations must develop effective strategies based on relationships with stakeholders and profit decisions, and cost-based in order to obtain competitive advantage. To satisfy customers' needs, the organizations seek a position of superiority over its competitors. To deploy its activities and to achieve its objectives, any organization must dispose resources such as material, human, financial, informational, and technological. This chapter treats a very interesting theme, that of procurement, as commercial activity, in the complex activities of organizations. The chapter starts with the literature in the field and presents the evolution of the process, the objectives, the roles, the functions, the activities, and the typology. The author presents the impact the new technologies have on procurement process, using a simulation model, based on mathematical and statistical models and IT programs.
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Rosenzweig, Cynthia, and Daniel Hillel. "Regional Activities in a Global Framework: Developing and Developed Countries." In Climate Variability and the Global Harvest. Oxford University Press, 2008. http://dx.doi.org/10.1093/oso/9780195137637.003.0012.
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Regional studies and activities related to the El Niño–Southern Oscillation (ENSO) and other oscillations, seasonal climate prediction, and agricultural impacts are in progress around the world (figure 7.1). Here we describe some regional impacts and programs in place that are entraining climate information into decision making. Elements of these activities include the definition of the agricultural or other targeted systems; exploration of the social, political, and cultural contexts; examination of the temporal and spatial patterns of physical and biological impacts related to ENSO; analysis of economic effects; development and testing of seasonal climate forecasts and their delivery; investigation of crop management and other adaptations leading to implementation of dynamic risk-management strategies; and the development and evaluation of programs. In northern Peru, El Niño events bring torrential rains and floods that damage crops by eroding slopes, silting valleys, and oversaturating soils. The precipitation regime of Chile is likely to be intensified as well when El Niño events occur (Meza et al., 2003). Downscaled seasonal climate forecasts and crop growth models have been used to evaluate the impact of ENSO and management responses on crops in the Andean highlands of Peru (Baigorria, 2007); and Meza (2007) combined stochastic modeling of meteorological variables, a simple soil crop algorithm, and a mathematical programming model to assess the value of ENSO information for irrigation in the Maipo River Basin, Chile. Central America, being a narrow strip of land tightly squeezed between the Atlantic and Pacific oceans, is particularly influenced by major global climate variability systems, especially the El Nino–Southern Oscillation and the Arctic Oscillation (AO; M. Campos and P. Ramirez, personal communication, 2007; Rosenzweig et al., 2007). El Niño events are associated with dry summers on the Pacific coast and wet summers on the Caribbean coast, while the opposite pattern is associated with La Niña. A decrease in winter rainfall on the Caribbean coast since the late 1970s has been linked to changes in the Arctic Oscillation. Events with important economic and social consequences affected Central America in 1926, 1945–56, 1956–57, 1965, 1972–73, 1982–83, 1992–94, and 1997–98 (Ramirez, 2005).
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Werner, Andreas. "Digital Inventory Optimization." In Technology Optimization and Change Management for Successful Digital Supply Chains, 192–216. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-7700-3.ch010.
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This chapter provides an overview of select inventory optimization (IO) techniques for single and multi-echelon optimization. The main goal is to familiarize the reader with various IO models by providing a clearly structured approach, improving the reader's understanding of the mathematical concepts, and by providing an ample number of examples. Furthermore, the guaranteed service model for a three stage serial supply chain is introduced to show the effects of keeping inventory at different echelons in the supply chain in regards to total cost. Lastly an inventory planning maturity model is presented to show actionable next steps to the practitioner.
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"DETECTION OF PARAMETER CHANGES AT UNKNOWN TIMES IN LINEAR REGRESSION MODELS." In Mathematical Statistics Theory and Applications, 389–92. De Gruyter, 1987. http://dx.doi.org/10.1515/9783112319086-059.
Full textConference papers on the topic "Coast changes – Mathematical models"
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Fritzen, C. P., D. Jennewein, and Th Kiefer. "Damage Detection Based on Vibration Measurements and Inaccurate Models." In ASME 1997 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/detc97/vib-4156.
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Abstract The paper presents a model-based approach for the detection of structural damage with respect to location and extent from measured vibration test data. The method which is tolerant to small modeling errors is based upon an analytically redundant mathematical model approximately representing the undamaged structure. The motivation was that in many practical cases it is not possible to obtain perfect correlation between the undamaged system and the original model due to modeling uncertainties or excessive modeling cost. On the other hand, in the early phase of damage evolution the changes of the dynamical characteristics are very small. If the changes due to the damage are superimposed by the effects of mismodeling it is nearly impossible to get reliable diagnostic results. Therefore, an approach is presented here for the case that a perfect model cannot be obtained. The resulting inverse problem usually is ill-posed, so that special attention must be paid to its accurate numerical solution. The application to damage detection problems requires the reduction of a large set of damage parameter candidates to a small subset of one or two parameters really describing the local change of the system. An orthogonalization strategy is given to reduce the parameter set and Akaike’s information criterion is used to confirm the correct size of the parametrization. The method is applied to two laboratory structures: a multi-story frame and a damaged plate. The results show that the algorithm is able to localize and quantify the damage also in the presence of modeling errors.
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Voronkova, Eva B., and Daria I. Zhuravleva. "Sensitivity analysis of mathematical models of the IOP changes." In 2015 International Conference "Stability and Control Processes" in Memory of V.I. Zubov (SCP). IEEE, 2015. http://dx.doi.org/10.1109/scp.2015.7342197.
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Taylor, Katherine A., Pulkit Shamshery, Ruo-Qian Wang, and Amos G. Winter. "A Mathematical Model for Pressure Compensating Emitters." In ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/detc2015-47519.
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This paper presents a mathematical model investigating the physics behind pressure-compensating (PC) drip irrigation emitters. A network of PC emitters, commonly known as drip irrigation, is an efficient way to deliver water to crops while increasing yield. Irrigation can provide a means for farmer to grow more sensitive, and profitable crops and help billions of small-holder farmers lift themselves out of poverty. Making drip irrigation accessible and economically viable is important for developing farmers as most face the challenges of water scarcity, declining water tables and lack of access to an electrical grid. One of the main reasons for the low adoption rate of drip irrigation in the developing world is the relatively high cost of the pumping power. It is possible to reduce this cost by reducing the required activation pressure of the emitters, while maintaining the PC behavior. The work presented here provides a guide of how design changes in the emitter could allow for a reduction in the activation pressure from 1 bar to approximately 0.1 bar. This decrease in the activation pressure of each emitter in turn decreases the system driving pressure. This reduction of driving pressure will decrease the energy need of pumping, making a solar-powered system affordable for small-acreage farmers. This paper develops a mathematical model to describe the PC behavior in a commercially available emitter. It is a 2D model that explains the relationship between the pressure, structural deformation and fluid flow within a PC emitter. A parametric study has been performed to understand the effects of geometric and material parameters with regards to the activation pressure and PC behavior. This knowledge will help guide the designs and prototypes of optimized emitters with a lower activation pressure, while also providing the PC behavior.
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Pe´rez Sa´nchez, Mari´a M., David Balam Tamayo, and Ricardo H. Cruz Estrada. "Design and Construction of a Dual Axis Passive Solar Tracker, for Use on Yucata´n." In ASME 2011 5th International Conference on Energy Sustainability. ASMEDC, 2011. http://dx.doi.org/10.1115/es2011-54428.
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In this investigation, we propose to use the thermal expansion properties of metals in a bimetallic strip as a base of operation of a passive solar tracker. The design process involved the determination of all aspects necessary to make a first prototype based on requirements and operating conditions previously identified. Predictive mathematical models were used to decide critical aspects. Certainly, some aspects of the design were determined experimentally to ensure the proper functioning of the solar tracker. The product of this research was the construction of a prototype with the ability to be placed with an average angular difference of 25 degrees to the position of the sun, under controlled conditions. The device created is a passive solar tracker with two degrees of freedom, one used to track the sun daily, operates automatically actuated by the bimetallic strip, the other one is manually adjusted in seasonal changes to compensate the variation in the decline of the sun along the year. Although the accuracy of the system is low, the cost of production is well below the purchase price of any commercial solar tracker, and its construction is simple, making it an economical alternative to increase the production of photovoltaic energy on a PV panel currently fixed.
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Okafor, Charles, Patrick Verdin, and Phill Hart. "CFD Investigation of Downhole Natural Gas Separation Efficiency in the Churn Flow Regime." In SPE Gulf Coast Section Electric Submersible Pumps Symposium. SPE, 2021. http://dx.doi.org/10.2118/204509-ms.
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Abstract Downhole Natural Gas Separation Efficiency (NGSE) is flow regime dependent, and current analytical models in certain conditions lack accuracy. Downhole NGSE was investigated through 3D Computational Fluid Dynamics (CFD) transient simulations for pumping wells in the Churn flow regime. The Volume of Fluid (VOF) multiphase model was considered along with the k – ε turbulence model for most simulations. A mesh independence study was performed, and the final model results validated against experimental data, showing an average error of less than 6 %. Numerical simulation results showed that the steady state assumption used by current mathematical models for churn flow can be inaccurate. Several key parameters affecting the NGSE were identified, and suggestions for key improvements to the widely used mathematical formulations for viscous flow provided. Sensitivity studies were conducted on fluid/geometric parameters and operating conditions, to gain a better understanding of the influence of each parameter on NGSE. These are important results as they equip the ESP engineer with additional knowledge to maximise the NGSE from design stage to pumping operations.
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Barbarossa, F., M. E. Rife, M. Carnevale, A. B. Parry, J. S. Green, and L. di Mare. "Fast Optimisation of a Three-Dimensional Bypass System Using a New Aerodynamic Design Method." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63324.
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The propulsive efficiency of civil aviation power plants can be effectively improved by increasing the bypass ratio. Higher bypass ratios, however, exacerbate issues of performance, stability and integrity due to the interaction between the engine pylon, the outlet guide vanes (OGV) and the fan. These issues are due to the distortion of the static pressure field at fan exit due to the presence of the pylon and its transmission through the OGV bladerow and are more pronounced the closer the components of the low pressure compression (LPC) system are. These issues make a rational and effective design of the LPC system of paramount importance for the success of very high-bypass ratio engines. At the preliminary design phase, methods that utilise computational fluid dynamics (CFD) are prohibitively expensive, particularly if they are used as part of optimisation processes involving highly three dimensional, non-axisymmetric OGV designs. An alternative method is being developed exploiting the simplicity and the accuracy of surface singularity element methods to investigate the sensitivity of the bypass system to changes in the design variables. Although the singularity method is based on simplified assumptions of inviscid, incompressible flow, it still performs remarkably well when combined with a tailored optimisation technique. This paper discusses the optimisation framework in detail, including the underlying mathematical models that describe the three-dimensional aerodynamic flowfield as well as the optimisation tools, variables and cost functions used within the optimisation process. The results show that the proposed approach can be used to explore quickly and efficiently a far wider design space than attempted so far in literature. Furthermore, the proposed method leads to non-axysymmetric cascade designs whereby every vane has the same load as the nominal vane whilst greatly reducing the static pressure distortion at fan exit.
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Scott, David A., Alexandre Lamoureux, and B. Rabi Baliga. "Computational Investigation of Laminar Mixed Convection in a Vertical Pipe With Slurries of a Microencapsulated Phase-Change Material in Distilled Water." In 2010 14th International Heat Transfer Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ihtc14-22974.
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A computational investigation of steady, laminar, mixed convection in a vertical pipe, with essentially uniform heat flux imposed on its outer surface and slurries of a microencapsulated phase-change material (MCPCM) particles suspended in distilled water as the working fluid flowing upwards, is presented. The MCPCM particles considered here have a core of solid-liquid PCM contained in a thin solid shell. The mean effective diameter of these particles is 2.5μm; the melting of the core PCM takes place primarily in the temperature range 26°C to 30°C; and the latent heat of fusion of this PCM is 129.5kJ/kg. The total length of the pipe is 2.2479m; and its inside and outside diameters are 0.01257m and 0.01588m, respectively. The main contributions of this paper are the following: i) a homogenous mathematical model is shown to be applicable to the aforementioned mixed convection phenomena; ii) correlations for the effective properties of the MCPCM slurries and procedures for their implementation are presented; iii) difficulties with the standard definition of bulk temperature when the specific heat of the fluid changes significantly with temperature are elaborated; iv) a modified bulk temperature that overcomes these difficulties is proposed; v) a finite volume method (FVM) for the solution of the proposed mathematical model is described briefly; and vi) the numerical results are presented, compared to complementary experimental data, and discussed. These comparisons show that proposed model and FVM allow cost-effective computer simulations of the problems of interest.
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Abrahamson, Shaun, David Wallace, Nicola Senin, and Nick Borland. "Integrated Engineering, Geometric, and Customer Modeling: LCD Projector Design Case Study." In ASME 1999 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/detc99/cie-9084.
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Abstract This paper describes an integrated product design study conducted with Polaroid Corporation for a liquid crystal display video projector, applying a research system called DOME. The services of distributed objects — encapsulating CAE simulations, component catalogs, manufacturing cost models, geometric and configuration models, customer preference models, and environmental life-cycle assessment — are mathematically related to form an integrated product system model. Software objects providing optimization and decision support are also included in the model to create a design tradeoff environment. As such, designers can obtain sales predictions based upon configuration changes and make tradeoffs with other requirements. Benchmarking suggests there would be approximately a 30% increase in the time to fully evaluate the first design configuration due to the overhead of creating the integrated system model. However, the time to fully evaluate subsequent alternatives may be reduced from months to minutes.
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Hehenberger, Peter, Alexander Egyed, and Klaus Zeman. "Consistency Checking of Mechatronic Design Models." In ASME 2010 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/detc2010-28615.
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During all phases of the design process there is a need to build models. Hierarchical models are very important tools for complex activities such as engineering design. In engineering of high performance products, mathematical modeling and simulation, i.e. experimenting with computer-based models, is an increasingly important technique for solving problems, evaluating solutions and making decisions. However, large design models may contain thousands of model elements. Designers easily get overwhelmed maintaining the correctness of such design models over time. Not only is it hard to detect new errors when the model changes but it is also hard to keep track of known errors. In the software engineering community this problem is known as a consistency problem and errors in models are known as inconsistencies. This paper presents an approach for consistency checking of mechatronic design models.
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Le, H. Nam, David C. Wynn, and P. John Clarkson. "Evaluating the Impacts of Iteration on PD Processes by Transforming Task Network Models Into System Dynamics Models." In ASME 2010 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/detc2010-28317.
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Iteration is unavoidable in the design process and should be incorporated when planning and managing projects in order to minimize surprises and reduce schedule distortions. However, planning and managing iteration is challenging because the relationships between its causes and effects are complex. Most approaches which use mathematical models to analyze the impact of iteration on the design process focus on a relatively small number of its causes and effects. Therefore, insights derived from these analytical models may not be robust under a broader consideration of potential influencing factors. In this article, we synthesize an explanatory framework which describes the network of causes and effects of iteration identified from the literature, and introduce an analytic approach which combines a task network modeling approach with System Dynamics simulation. Our approach models the network of causes and effects of iteration alongside the process architecture which is required to analyze the impact of iteration on design process performance. We show how this allows managers to assess the impact of changes to process architecture and to management levers which influence iterative behavior, accounting for the fact that these changes can occur simultaneously and can accumulate in non-linear ways. We also discuss how the insights resulting from this analysis can be visualized for easier consumption by project participants not familiar with simulation methods.
Reports on the topic "Coast changes – Mathematical models"
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Ding, Yan, Sung-Chan Kim, Rusty L. Permenter, Richard B. Styles, and Jeffery A. Gebert. Simulations of Shoreline Changes along the Delaware Coast. Engineer Research and Development Center (U.S.), January 2021. http://dx.doi.org/10.21079/11681/39559.
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This technical report presents two applications of the GenCade model to simulate long-term shoreline evolution along the Delaware Coast driven by waves, inlet sediment transport, and longshore sediment transport. The simulations also include coastal protection practices such as periodic beach fills, post-storm nourishment, and sand bypassing. Two site-specific GenCade models were developed: one is for the coasts adjacent to the Indian River Inlet (IRI) and another is for Fenwick Island. In the first model, the sediment exchanges among the shoals and bars of the inlet were simulated by the Inlet Reservoir Model (IRM) in the GenCade. An inlet sediment transfer factor (γ) was derived from the IRM to quantify the capability of inlet sediment bypassing, measured by a rate of longshore sediments transferred across an inlet from the updrift side to the downdrift side. The second model for the Fenwick Island coast was validated by simulating an 11-y ear-long shoreline evolution driven by longshore sediment transport and periodic beach fills. Validation of the two models was achieved through evaluating statistical errors of simulations. The effects of the sand bypassing operation across the IRI and the beach fills in Fenwick Island were examined by comparing simulation results with and without those protection practices. Results of the study will benefit planning and management of coastal sediments at the sites.