Статті в журналах: "System Dynamics Model (SDM)"

1

Dang, Dongfang, Feng Gao, and Qiuxia Hu. "Motion Planning for Autonomous Vehicles Considering Longitudinal and Lateral Dynamics Coupling." Applied Sciences 10, no. 9 (May 2, 2020): 3180. http://dx.doi.org/10.3390/app10093180.

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Vehicles are highly coupled and multi-degree nonlinear systems. The establishment of an appropriate vehicle dynamical model is the basis of motion planning for autonomous vehicles. With the development of autonomous vehicles from L2 to L3 and beyond, the automatic driving system is required to make decisions and plans in a wide range of speeds and on bends with large curvature. In order to make precise and high-quality control maneuvers, it is important to account for the effects of dynamical coupling in these working conditions. In this paper, a new single-coupled dynamical model (SDM) is proposed to deal with the various dynamical coupling effects by identifying and simplifying the complicated one. An autonomous vehicle motion planning problem is then formulated using the nonlinear model predictive control theory (NMPC) with the SDM constraint (NMPC-SDM). We validated the NMPC-SDM with hardware-in-the-loop (HIL) experiments to evaluate improvements to control performance by comparing with the planners original design, using the kinematic and single-track models. The comparative results show the superiority of the proposed motion planning algorithm in improving the maneuverability and tracking performance.

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YU, Xiaohan, Zeshui XU, and Shousheng LIU. "SYSTEMATIC DECISION MAKING: A EXTENDED MULTI-CRITERIA DECISION MAKING MODEL." Technological and Economic Development of Economy 23, no. 1 (January 22, 2017): 157–77. http://dx.doi.org/10.3846/20294913.2016.1212121.

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Considering some complex multi-criteria decision making (MCDM) problems, in which decision environment is dynamic, there are various interdependences among criteria, and plans (systematized alternatives) consisting of multiple time sequential interdependent actions, cannot be well handled by means of the existing MCDM methods, therefore, we develop a systematic decision making (SDM) as an improvement and supplement of the classic MCDM in this paper. The SDM is for prescribing methods of evaluating and selecting the most favourite plan (a system) from a group of feasible ones concerning influences of time-varying criteria system under dynamic external environment. Through detailed analysis, we separate a SDM problem into multi-period MCDM subproblems, and then a plan can be a combination of time sequential strategies in which each strategy (a subset of actions) is a feasible decision choice of corresponding MCDM sub-problem. After clarifying variety of interdependences, interactions and interrelationships in the SDM problems, such as criteria-interdependences, action-interdependences, interactions between criteria and criteria system, interactions between actions and strategies, interactions between strategies and plans, interactions between internal environment (criteria system) and external environment, feedbacks from external environment to the corresponding MCDM sub-problems, and interrelationships among MCDM sub-problems and so on, we transform the SDM into multi-period interrelated MCDM model which can be dealt with more easily by using multiple optimization models. At the end of the paper, three typical properties of the SDM are proposed and most of the existing MCDM models are pointed out as special cases of the SDM.

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3

Litvinenko, V., and M. Dvoinikov. "Methodology for determining the parameters of drilling mode for directional straight sections of well using screw downhole motors." Journal of Mining Institute 241 (February 25, 2020): 105. http://dx.doi.org/10.31897/pmi.2020.1.105.

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Article presents results of study on possibility of increasing the efficiency of drilling directional straight sections of wells using screw downhole motors (SDM) with a combined method of drilling with rotation of drilling string (DS). Goal is to ensure steady-state operation of SDM with simultaneous rotation of DS by reducing the amplitude of oscillations with adjusting the parameters of drilling mode on the basis of mathematical modeling for SDM – DS system.Results of experimental study on determination of extrema distribution of lateral and axial oscillations of SDM frame depending on geometrical parameters of gerotor mechanism and modes ensuring stable operation are presented.Approaches to development of a mathematical model and methodology are conceptually outlined that allow determining the range of self-oscillations for SDM – DS system and boundaries of rotational and translational wave perturbations for a heterogeneous rod with an installed SDM at drilling directional straight sections of well. This mathematical model of SDM – DS system's dynamics makes it possible to predict optimal parameters of directional drilling mode that ensure stable operation of borehole assembly.

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SERAJI, Salameh, Hasan MEHRMANESH, and Ahmad R. KASRAEE. "Design of a System Dynamics Model (SDM) to Evaluate the Supply Chain of Biological Products." International Journal of Engineering Technologies IJET 7, no. 2 (June 24, 2021): 20–32. http://dx.doi.org/10.19072/ijet.827233.

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Bottero, Marta, Giulia Datola, and Elena De Angelis. "A System Dynamics Model and Analytic Network Process: An Integrated Approach to Investigate Urban Resilience." Land 9, no. 8 (July 23, 2020): 242. http://dx.doi.org/10.3390/land9080242.

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During the last decade, the concept of urban resilience has been increasingly implemented in urban planning, with the main aim to design urban development strategies. Urban resilience is a multi-dimensional and dynamic concept. When applied to urban planning, it consists of studying cities as complex socio-economic systems. Municipalities are currently working to undertake appropriate actions to enrich the resilience of cities. Moreover, several difficulties concern the evaluation of the impacts over time of the strategies designed to enhance urban resilience. The present paper proposes an integrated approach based on the System Dynamics Model (SDM) and the Analytic Network Process (ANP). The objective of this research is to describe the method and to illustrate its application to the area called Basse di Stura, located in the city of Turin, Italy. The method is applied to evaluate the possible impacts of two different urban scenarios in terms of the change of urban resilience performance over time. The final result is represented by an index that describes urban resilience performance.

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Momodu, Abiodun S., and Lucy Kivuti-Bitok. "System dynamic modelling of electricity planning and climate change in West Africa." AAS Open Research 1 (May 2, 2018): 15. http://dx.doi.org/10.12688/aasopenres.12852.1.

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Background: It is imperative to develop an efficient strategic approach to managing the push-pull factor in economic development, particularly as relates to climate change and energy interactions in the West African Region. This article demonstrates the use of System Dynamics Modelling (SDM) for that purpose; to manage the development of energy growth with reduced impact in regards to climate change. The complexities of energy planning in relation to climate change necessitates the need for the tool to examine low carbon economy mixed with traditional approaches of planning. Methods: Vensim DSS version 6.2 was used to develop the model. WAPP member country level data elicited from WAPP and ECOWAS Regional Electricity Regulatory Authority (ERERA) serves as the set of basic data used to develop and run the main model. These were complemented with other data elicited from various journal articles and internet sources. These include population and its average growth rate, GDP, per capita income, average per capita electricity demand, electricity generated, average electricity tariff, generation technology type, amongst others. Results: SDM demonstrates the capability to understand the theoretical frame for trade-offs between economic development and climate change, by handling the nonlinear relationship between generation adequacy and greenhouse gas (GHG) emission reduction for better targeted strategic regional intervention on climate change. Conclusion: The primary goal of this paper was to demonstrate the use of SDM to aid in resource planning in an inexpensive way to examine low carbon pathway. With the SDM, the goal of low carbon pathway in the energy system was achieved without the cost of controlled trials.

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Momodu, Abiodun S., and Lucy Kivuti-Bitok. "System dynamic modelling of electricity planning and climate change in West Africa." AAS Open Research 1 (October 4, 2018): 15. http://dx.doi.org/10.12688/aasopenres.12852.2.

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Background: It is imperative to develop an efficient strategic approach to managing the push-pull factor in economic development, particularly as relates to climate change and energy interactions in the West African Region. This article demonstrates the use of System Dynamics Modelling (SDM) for that purpose; to manage the development of energy growth with reduced impact in regards to climate change. The complexities of energy planning in relation to climate change necessitates the need for the tool to examine low carbon economy mixed with traditional approaches of planning. Methods: Vensim DSS version 6.2 was used to develop the model. WAPP member country level data elicited from WAPP and ECOWAS Regional Electricity Regulatory Authority (ERERA) serves as the set of basic data used to develop and run the main model. These were complemented with other data elicited from various journal articles and internet sources. These include population and its average growth rate, GDP, per capita income, average per capita electricity demand, electricity generated, average electricity tariff, generation technology type, amongst others. Results: SDM demonstrates the capability to understand the theoretical frame for trade-offs between economic development and climate change, by handling the nonlinear relationship between generation adequacy and greenhouse gas (GHG) emission reduction for better targeted strategic regional intervention on climate change. Conclusion: The primary goal of this paper was to demonstrate the use of SDM to aid in resource planning in an inexpensive way to examine low carbon pathway. With the SDM, the goal of low carbon pathway in the energy system was achieved without the cost of controlled trials.

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8

Tuu, Nguyen Thanh, Jeejae Lim, Seungdo Kim, Van Pham Dang Tri, Hyeonkyeong Kim, and Jeonghoon Kim. "Surface water resource assessment of paddy rice production under climate change in the Vietnamese Mekong Delta: a system dynamics modeling approach." Journal of Water and Climate Change 11, no. 2 (January 2, 2019): 514–28. http://dx.doi.org/10.2166/wcc.2019.176.

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Abstract Water demands and stresses in the Vietnam Mekong Delta (VMD) are of high concern for the coming decade. System dynamics modeling (SDM) can be used to understand the impacts of the changes on water resources at a regional scale. SDM framework was applied to assess the impacts of land use changes and climate on surface water resource in the VMD. The developed model was modified from a global-scale model and added in-situ specific variables to model the conditions of the VMD using historical data during 1986–2005, and future projections to 2050 under two Representative Concentration Pathways scenarios (RCP4.5 and RCP8.5). Projected changes in land use and population were based on the most recent governmental resolution to support adaptation and the national plans. Temperature and rainfall changes cause the increase in water stress; however, it could be mitigated by shifting from three to two crops of rice each year. Water stress differs from place to place, such as in freshwater and brackish coastal zones. Water stress is most strongly affected by changed temperature, rather than rainfall. The developed system dynamics model and framework can be effectively applied in the VMD to support decision-making about sustainable water use for paddy rice.

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Farhan, Muhammad, Hassan Mobeen Alam, and Shaista Jabeen. "Managing Equity Investment Risk and Rate of Return Risk in Islamic Banking: A System Thinking Approach." Business & Economic Review 13, no. 1 (March 15, 2021): 43–64. http://dx.doi.org/10.22547/ber/13.1.3.

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This study aims to examine and explore the risk management practices with respect to Rate of Return Risk (RORR) and Equity Investment Risk (EIR) in the Islamic Banking Institutions (IBIs) of Pakistan through a systematic model which is called System Dynamic Model (SDM) by using system thinking methodology. This study has been conducted in three sequential phases to develop the qualitative System Dynamic Model for Rate of Return Risk Management and Equity Investment Risk Management. Firstly, the researchers developed preliminary Causal Loop Diagrams (CLD) based on the initial understanding achieved from the causal interconnections between various RORR and EIR characters through extensive literature review. Secondly, the researchers conducted semi-structured interviews with the experts to ratify, endorse and refine the initial CLD. Lastly, the data collected through interviews was analyzed to develop the final refined qualitative SDM. The study's findings indicate that the identification and measurement of the RORR and EIR in IBIs in Pakistan need to be strengthened by developing appropriate methodology. Moreover, the practices adopted by these financial institutions to mitigate and control the exposures of RORR and EIR are good and effective. This Qualitative SDM provides practical, constructive and productive understanding to the managers, policy-makers, regulators, shareholders and scholars regarding the RORR and EIR management mechanism of IBIs of Pakistan.

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Coyle, R. G. "A system dynamics model of aircraft carrier survivability." System Dynamics Review 8, no. 3 (1992): 193–212. http://dx.doi.org/10.1002/sdr.4260080302.

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Homer, Jack B. "A system dynamics model of national cocaine prevalence." System Dynamics Review 9, no. 1 (1993): 49–78. http://dx.doi.org/10.1002/sdr.4260090104.

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12

Terzi, Stefano, Janez Sušnik, Stefan Schneiderbauer, Silvia Torresan, and Andrea Critto. "Stochastic system dynamics modelling for climate change water scarcity assessment of a reservoir in the Italian Alps." Natural Hazards and Earth System Sciences 21, no. 11 (November 19, 2021): 3519–37. http://dx.doi.org/10.5194/nhess-21-3519-2021.

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Abstract. Water management in mountain regions is facing multiple pressures due to climate change and anthropogenic activities. This is particularly relevant for mountain areas where water abundance in the past allowed for many anthropogenic activities, exposing them to future water scarcity. Here stochastic system dynamics modelling (SDM) was implemented to explore water scarcity conditions affecting the stored water and turbined outflows in the Santa Giustina (S. Giustina) reservoir (Autonomous Province of Trento, Italy). The analysis relies on a model chain integrating outputs from climate change simulations into a hydrological model, the output of which was used to test and select statistical models in an SDM for replicating turbined water and stored volume within the S. Giustina dam reservoir. The study aims at simulating future conditions of the S. Giustina reservoir in terms of outflow and volume as well as implementing a set of metrics to analyse volume extreme conditions. Average results on 30-year slices of simulations show that even under the short-term RCP4.5 scenario (2021–2050) future reductions for stored volume and turbined outflow are expected to be severe compared to the 14-year baseline (1999–2004 and 2009–2016; −24.9 % of turbined outflow and −19.9 % of stored volume). Similar reductions are expected also for the long-term RCP8.5 scenario (2041–2070; −26.2 % of turbined outflow and −20.8 % of stored volume), mainly driven by the projected precipitations having a similar but lower trend especially in the last part of the 2041–2070 period. At a monthly level, stored volume and turbined outflow are expected to increase for December to March (outflow only), January to April (volume only) depending on scenarios and up to +32.5 % of stored volume in March for RCP8.5 for 2021–2050. Reductions are persistently occurring for the rest of the year from April to November for turbined outflows (down to −56.3 % in August) and from May to December for stored volume (down to −44.1 % in June). Metrics of frequency, duration and severity of future stored volume values suggest a general increase in terms of low volume below the 10th and 20th percentiles and a decrease of high-volume conditions above the 80th and 90th percentiles. These results point at higher percentage increases in frequency and severity for values below the 10th percentile, while volume values below the 20th percentile are expected to last longer. Above the 90th percentile, values are expected to be less frequent than baseline conditions, while showing smaller severity reductions compared to values above the 80th percentile. These results call for the adoption of adaptation strategies focusing on water demand reductions. Months of expected increases in water availability should be considered periods for water accumulation while preparing for potential persistent reductions of stored water and turbined outflows. This study provides results and methodological insights that can be used for future SDM upscaling to integrate different strategic mountain socio-economic sectors (e.g. hydropower, agriculture and tourism) and prepare for potential multi-risk conditions.

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Ordoñez, Maria-Cristina, Leopoldo Galicia, and Karla Valladares-Samperio. "Carbon and Nitrogen Dynamics in Mexican Management Forest: Simulation of Biomass Harvesting and C and N Amendments." Forest Science 68, no. 2 (December 18, 2021): 172–83. http://dx.doi.org/10.1093/forsci/fxab059.

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Abstract Sustainable silvicultural management requires the maintenance of long-term ecosystem processes. We used the CENTURY model to simulate the impact of wood extraction and organic amendments on aboveground biomass, carbon (C) storage, and the availability of nitrogen (N) in the two dominant silvicultural methods in Mexico: the silvicultural development method (SDM) and irregular forest management (IFM). The values of the mean absolute percentage error for the SDM and IFM were 2.1% and 3.3% for C in aboveground biomass, 5.7% and 5.0% for soil organic carbon (SOC), and 14.9% and 21.6% for N, respectively. Simulation for the SDM (1967–2068) suggested a reduction of ~7% in C in soil, microbial biomass, and litter, 9% in aboveground biomass C, and ~20% in the mineral N available. For IFM, the simulation (2009–2019) suggested a reduction of 14% in the accumulation of aboveground biomass and 13% in the mineral N available. Simulation of the adoption of management practices suggested that N mineral availability would increase by 2%–3% without drastically reducing the SOC, improving aboveground biomass production by ~7%, in each management system. Study Implications In Mexico, current silvicultural management is causing alterations in the biological and chemical processes of the soil, but the future impacts on the production of forest wood and loss of fertility cannot be estimated by direct measurements. We simulated two silvicultural management alternatives with two rotation cycles and measured the response in terms of SOC, nitrogen availability, and aboveground biomass. The model shows that improving forest residue management by adding organic amendments to the soil would counteract changes in soil microbial activity, nitrogen availability, SOC, and aboveground biomass in the future. Managers should consider this information to reorient current crop residue management to achieve the objectives and the sustainability of forest management in Mexican temperate forests.

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Naill, Roger F. "A system dynamics model for national energy policy planning." System Dynamics Review 8, no. 1 (1992): 1–19. http://dx.doi.org/10.1002/sdr.4260080102.

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Zhao, Sen, Malte F. Stuecker, Fei-Fei Jin, Juan Feng, Hong-Li Ren, Wenjun Zhang, and Jianping Li. "Improved Predictability of the Indian Ocean Dipole Using a Stochastic Dynamical Model Compared to the North American Multimodel Ensemble Forecast." Weather and Forecasting 35, no. 2 (February 17, 2020): 379–99. http://dx.doi.org/10.1175/waf-d-19-0184.1.

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Abstract This study assesses the predictive skill of eight North American Multimodel Ensemble (NMME) models in predicting the Indian Ocean dipole (IOD). We find that the forecasted ensemble-mean IOD–El Niño–Southern Oscillation (ENSO) relationship deteriorates away from the observed relationship with increasing lead time, which might be one reason that limits the IOD predictive skill in coupled models. We are able to improve the IOD predictive skill using a recently developed stochastic dynamical model (SDM) forced by forecasted ENSO conditions. The results are consistent with the previous result that operational IOD predictability beyond persistence at lead times beyond one season is mostly controlled by ENSO predictability and the signal-to-noise ratio of the Indo-Pacific climate system. The multimodel ensemble (MME) investigated here is found to be of superior skill compared to each individual model at most lead times. Importantly, the skill of the SDM IOD predictions forced with forecasted ENSO conditions were either similar or better than those of the MME IOD forecasts. Moreover, the SDM forced with observed ENSO conditions exhibits significantly higher IOD prediction skill than the MME at longer lead times, suggesting the large potential skill increase that could be achieved by improving operational ENSO forecasts. We find that both cold and warm biases of the predicted Niño-3.4 index may cause false alarms of negative and positive IOD events, respectively, in NMME models. Many false alarms for IOD forecasts at lead times longer than one season in the original forecasts disappear or are significantly reduced in the SDM forced by forecasted ENSO conditions.

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Qin, Guodong, Huapeng Wu, and Aihong Ji. "Equivalent Dynamic Analysis of a Cable-Driven Snake Arm Maintainer." Applied Sciences 12, no. 15 (July 26, 2022): 7494. http://dx.doi.org/10.3390/app12157494.

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In this paper, we investigate a design method for a cable-driven snake arm maintainer (SAM) and its dynamics modelling. A SAM can provide redundant degrees of freedom and high structural stiffness, as well as high load capacity and a simplified structure ideal for various narrow and extreme working environments, such as nuclear power plants. However, their serial-parallel configuration and cable drive system make the dynamics of a SAM strongly coupled, which is not conducive to accurate control. In this paper, we propose an equivalent dynamics modelling method for the strongly coupled dynamic characteristics of each joint cable. The cable traction dynamics are forcibly decoupled using force analysis and joint torque equivalent transformation. Then, the forcibly equivalent dynamic model is obtained based on traditional series robot dynamic modelling methods (Lagrangian method, etc.). To verify the correctness of the equivalent dynamics, a simple model-based controller is established. In addition, a SAM prototype is produced to collect joint angles and cable forces at different trajectories. Finally, the results of the equivalent dynamics control simulation and the prototype tests demonstrate the validity of the SAM structural design and the equivalent dynamics model.

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17

Eden, Colin. "Cognitive mapping and problem structuring for system dynamics model building." System Dynamics Review 10, no. 2-3 (1994): 257–76. http://dx.doi.org/10.1002/sdr.4260100212.

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Sirovs, Toms. "System Dynamic Theoretical Framework for Construction Management: A Case of Baltic States." Baltic Journal of Real Estate Economics and Construction Management 10, no. 1 (January 1, 2022): 113–28. http://dx.doi.org/10.2478/bjreecm-2022-0008.

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Abstract As a result of the rapid development of the construction industry, in recent years, research has increasingly used system dynamics (SD) modelling to determine the positive and negative causal feedback in various management processes. Given SD diverse approach to the management of construction companies and projects, it would be necessary to develop a framework for a system dynamics model (SDM) incorporating the main processes of the Baltic States by identifying and providing a systematic understanding of their distribution. Using literature analysis, this study provides the results of 79 selected scientific literature sources from 1991 to 2020. The obtained information is structured according to the annual volume of publications, country of affiliation, the most successful authors and the most popular scientific journals on the topic of the SD. With the assistance of bibliometric analysis and co-occurrence of keywords, system dynamics management processes in construction companies were structured, choosing the following separate elements: (1) project planning, (2) project management, (3) risk management, (4) project performance, (5) project productivity, (6) sustainability. Using a systematic approach, according to the framework of the model, the characteristics of each management process were classified and identified, dividing them into subgroups. The results of the analysis show that the overview of some SD components or processes is mostly provided, which emphasises its aspects and usability in company management, thus indicating the need to identify the framework of the process module. The introduction of the SD process framework in the company would gradually create a competitive advantage in market conditions.

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Ratna Dwi Puji Astuti. "Using System Dynamic Modeling for Improving Water Security in the Coastal Area: A Literature Review." Open Access Macedonian Journal of Medical Sciences 8, F (August 15, 2020): 143–54. http://dx.doi.org/10.3889/oamjms.2020.4395.

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BACKGROUND: Water is one of the basic materials of human existence. In respect this, many countries have been focused on water security agenda as one of the national strategic security. One of water security domains is coastal water security. Water security, due to the myriad of factors influencing water quantity and quality in coastal area, can be considered as a complex system. Due to the complexity and dynamic characteristic, system dynamic model (SDM) is needed to implement in coastal area to integrate all subsystem. AIM: This study aims to analyse the subsystems relating to coastal water security. The subsystem determination used to develop future policy-making relating to coastal water security. METHODS: For this purpose, a systematic literature review was conducted and a set of 12 papers was selected from 2009 – 2019. RESULTS: The papers’ analysis shows the applicability of SDM to solve complex problems. Water scarcity has been identified as a major problem in the coastal area, identified in eight papers. Three papers are related to water quality and only one paper relating to both. There are four major subsystems relating to coastal water security: environment, economic, social, and politic. Information about the aquaculture activities, the mechanism of coastal water pollution and water relating human health risk is still limited. CONCLUSION: We recommend use of SDM in the coastal water security to be extended to aquaculture, coastal water pollution and human health risk aspect in order to promote a holistic understanding of the complex issues and to develop more effective policies.

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Galimkair Mutanov, Sayabek Ziyadin, and Askhat Serikbekuly. "Application of System-Dynamic Modeling to Improve Distribution Logistics Processes in the Supply Chain." Communications - Scientific letters of the University of Zilina 22, no. 3 (July 8, 2020): 29–39. http://dx.doi.org/10.26552/com.c.2020.3.29-39.

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This article presents an approach of improve logistics processes with the system dynamics modeling of two different processes scenarios. System dynamics is used, not only as a causal loop diagram, but calculated measures of end-user satisfaction indicators were provided by experts, as well. Literature review of fundamental definitions and recent ideas in subject of supply chain management (SCM), system dynamics (SD), business processes model and notation (BPMN) and distribution logistics for dozens of major sources, has been made. In the work, methods of expert interviews, content analysis of recent publications, system-dynamic modeling and business process modeling, were used. Developed BPMN-models of distribution logistics business processes are given in Appendices #1 and #2.

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Homer, Jack B. "Partial-model testing as a validation tool for system dynamics (1983)." System Dynamics Review 28, no. 3 (July 2012): 281–94. http://dx.doi.org/10.1002/sdr.1478.

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Dural‐Selcuk, Gozdem, Huseyin Tunc, and S. Armagan Tarim. "An integrated economy‐demography model reframed in a system dynamics setting." System Dynamics Review 35, no. 4 (October 2019): 337–68. http://dx.doi.org/10.1002/sdr.1645.

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Bush, James W., Alan M. Schneider, Thomas L. Wachtel, and John E. Brimm. "Fluid therapy in acute large area burns: A system dynamics model." System Dynamics Review 1, no. 1 (1985): 20–41. http://dx.doi.org/10.1002/sdr.4260010104.

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Lukyanchuk, V. V., B. M. Lanetskii, I. V. Koval, Pavlo Open’ko, V. V. Tуurin, and V. V. Khoma. "Model of the Surface-to-Air Missile System Reliability during Long-Term Operation." Advances in Military Technology 16, no. 2 (December 14, 2021): 277–88. http://dx.doi.org/10.3849/aimt.01506.

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During the long-term operation, anti-aircraft missile weapons are characterized by the technical condition and level of reliability change influeincing the efficiency on the intended use. The article presents a model of surface-to-air missile system (SAMS) reliability during long-term operation, which contains a set of models, namely: a model of operation of ground combat assets (GCA) of SAMS according to the typical cyclogram of intended use (TCIU); a reliability dynamics model of SAMS GCA in the established system of maintenance and repair (SMR) and a reliability dynamics model of surface-to-air missiles (SAM) during extended usage. It is expedient to use the developed model at substantiation of requirements to the indicators of SAMS and SAM reliability for their development or modernization; when developing SAMS repair plans in terms of determining the time of SAMS GCA and (or) SAM repairing time and when developing methods for assessing the effectiveness of SAMS taking into account the duration of SAMS GCA and SAMS usage.

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Omwenga, Vincent O., Vaishnav Madhumati, Kumar Vinay, Sathyanarayan Srikanta, and Navakanta Bhat. "Mathematical Modelling of Combined Intervention Strategies for the Management and Control of Plasma Glucose of a Diabetes Mellitus Patient: A System Dynamic Modelling Approach." Mathematics 11, no. 2 (January 6, 2023): 306. http://dx.doi.org/10.3390/math11020306.

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With the rapid increase of diabetes mellitus cases in the world, management and control of the disease has become a complex and highly dynamic process. This challenge requires a multifaceted approach to manage and control the complications associated with the hyperglycaemia or hypoglycaemia conditions. This paper presents a mathematical model for determining the influence of combined intervention strategies in the management and control for the plasma glucose of the type II diabetes. System dynamics (SD) techniques were used in modelling the sub-compartments of biological systems of an Identifiable Patient (IP). The system dynamic model developed gave an illustration on how typical glucose-insulin dynamics occur at different intervention strategies involving varying amounts of carbohydrates taken, intensity of physical exercises, stress levels and the amount of exogenous insulin administered. The model was conceptualized within a semi-closed loop system representing the patient ecosystem by extending the Bergman Minimal Model. Stochastic differential equations (SDE) were used to capture the non-linear, continuous time varying interactions of the measurements associated with plasma glucose-insulin dynamics. The estimated results from the model showed combined intervention strategies of reduced amounts of carbohydrates intake, reduced stress levels and varying moderately high-to-low exercise intensity at a constant unit of exogenous insulin produced good plasma glucose levels control.

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Clark, Rolf, and Clark A. Omholt. "Projecting the future value of a variable in a system dynamics model." System Dynamics Review 5, no. 1 (1989): 81–86. http://dx.doi.org/10.1002/sdr.4260050107.

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27

Wittenberg, Jason. "On the very idea of a system dynamics model of Kuhnian science." System Dynamics Review 8, no. 1 (1992): 21–33. http://dx.doi.org/10.1002/sdr.4260080103.

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28

Gardiner, L. Keith, and Raymond C. Shreckengost. "A system dynamics model for estimating heroin imports into the United States." System Dynamics Review 3, no. 1 (1987): 8–27. http://dx.doi.org/10.1002/sdr.4260030103.

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29

Chew, Chee-Meng, Geok-Soon Hong, and Wei Zhou. "Series damper actuator system based on MR fluid damper." Robotica 24, no. 6 (July 3, 2006): 699–710. http://dx.doi.org/10.1017/s0263574706002876.

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In our recent work, we have proposed a novel force control actuator system called series damper actuator (SDA). We have since built an SDA system based on magneto-rheological fluid (MR) damper. In this paper, the dynamics property of SDA system based on the MR fluid damper (SMRDA) is investigated. The effect of the extra dynamics introduced by the MR fluid damper is revealed by comparing the SMRDA with the SDA system based on a linear Newtonian viscous damper (SNVDA). To linearize the constitutive property of the MR fluid damper, a modified Bingham model is proposed. A force feedback control loop is implemented after the linearization. An experimental SMRDA is built to illustrate the performance of the SDA system.

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30

Coyle, R. Geoffrey. "The use of optimization methods for policy design in a system dynamics model." System Dynamics Review 1, no. 1 (1985): 81–91. http://dx.doi.org/10.1002/sdr.4260010107.

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31

Guo, Xudong, Junbo Tong, Peiyu Chen, and Wenhui Fan. "The suppression effect of emotional contagion in the COVID-19 pandemic: A multi-layer hybrid modelling and simulation approach." PLOS ONE 16, no. 7 (July 28, 2021): e0253579. http://dx.doi.org/10.1371/journal.pone.0253579.

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The entire world has suffered a lot since the outbreak of the novel coronavirus (COVID-19) in 2019, so simulation models of COVID-19 dynamics are urgently needed to understand and control the pandemic better. Meanwhile, emotional contagion, the spread of vigilance or panic, serves as a negative feedback to the epidemic, but few existing models take it into consideration. In this study, we proposed an innovative multi-layer hybrid modelling and simulation approach to simulate disease transmission and emotional contagion together. In each layer, we used a hybrid simulation method combining agent-based modelling (ABM) with system dynamics modelling (SDM), keeping spatial heterogeneity while reducing computation costs. We designed a new emotion dynamics model IWAN (indifferent, worried, afraid and numb) to simulate emotional contagion inside a community during an epidemic. Our model was well fit to the data of China, the UK and the US during the COVID-19 pandemic. If there weren’t emotional contagion, our experiments showed that the confirmed cases would increase rapidly, for instance, the total confirmed cases during simulation in Guangzhou, China would grow from 334 to 2096, which increased by 528%. We compared the calibrated emotional contagion parameters of different countries and found that the suppression effect of emotional contagion in China is relatively more visible than that in the US and the UK. Due to the experiment results, the proposed multi-layer network model with hybrid simulation is valid and can be applied to the quantitative analysis of the epidemic trends and the suppression effect of emotional contagion in different countries. Our model can be modified for further research to study other social factors and intervention policies in the COVID-19 pandemic or future epidemics.

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32

Sterman, John D. "Response to “On the very idea of a system dynamics model of Kuhnian science”." System Dynamics Review 8, no. 1 (1992): 35–42. http://dx.doi.org/10.1002/sdr.4260080104.

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33

Barlas, Yaman. "Comments on “On the very idea of a system dynamics model of Kuhnian science”." System Dynamics Review 8, no. 1 (1992): 43–47. http://dx.doi.org/10.1002/sdr.4260080105.

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34

Radzicki, Michael J. "Reflections on “On the very idea of a system dynamics model of Kuhnian science”." System Dynamics Review 8, no. 1 (1992): 49–53. http://dx.doi.org/10.1002/sdr.4260080106.

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35

Su, Mao-Kang, Keh-Hsun Chen, and Huan-Chen Wang. "The spread of '88 Shanghai type-A hepatitis: A system dynamics model and analysis." System Dynamics Review 8, no. 3 (1992): 213–32. http://dx.doi.org/10.1002/sdr.4260080303.

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36

Hansen, Jan E., and Peter Bie. "Distribution of body fluids, plasma protein, and sodium in dogs: A system dynamics model." System Dynamics Review 3, no. 2 (1987): 116–35. http://dx.doi.org/10.1002/sdr.4260030204.

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37

Li, Xiaojuan, Chen Wang, Mukhtar A. Kassem, Hamed H. Alhajlah, and Samuel Bimenyimana. "Evaluation Method for Quality Risks of Safety in Prefabricated Building Construction Using SEM–SDM Approach." International Journal of Environmental Research and Public Health 19, no. 9 (April 24, 2022): 5180. http://dx.doi.org/10.3390/ijerph19095180.

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The construction of prefabricated buildings is an effective and efficient approach to improving construction processes and productivity. However, there are practical problems in this approach, such as listing, safety risk levels, and quality control. This study aims to develop a systematic approach for determining the key factors affecting prefabricated building projects’ quality and safety risk and assessing this risk. Based on the literature review, a structured questionnaire was distributed to 408 China-based construction organizations. Considering the factors of safety risk evaluation systems for construction, the safety risk model of prefabricated buildings is established and combined with structural equation modeling (SEM) and a system dynamic model (SDM). A detailed case study was conducted to verify the empirical findings. The results show that pre-construction, during-construction, and after-construction significantly influence the quality risk (from high to low). The final comprehensive score is 92.71, indicating that the construction safety of the residential building is generally controllable and the quality is guaranteed. Furthermore, the investment risk of such projects can be assessed using SEM and SDM. This study contributes to the literature by considering quality-risk-influencing factors in this field. Furthermore, the findings provide an understanding of implementation and quality risk control for prefabricated building projects and provide valuable information to departments in charge of improving the safety risk performance of such projects.

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38

Mujiono, Mujiono, and Aina Musdholifah. "Pengembangan Data Warehouse Menggunakan Pendekatan Data-Driven untuk Membantu Pengelolaan SDM." IJCCS (Indonesian Journal of Computing and Cybernetics Systems) 10, no. 1 (January 31, 2016): 1. http://dx.doi.org/10.22146/ijccs.11184.

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The basis of bureaucratic reform is the reform of human resources management. One supporting factor is the development of an employee database. To support the management of human resources required including data warehouse and business intelligent tools. The data warehouse is an integrated concept of reliable data storage to provide support to all the needs of the data analysis. In this study developed a data warehouse using the data-driven approach to the source data comes from SIMPEG, SAPK and electronic presence. Data warehouses are designed using the nine steps methodology and unified modeling language (UML) notation. Extract transform load (ETL) is done by using Pentaho Data Integration by applying transformation maps. Furthermore, to help human resource management, the system is built to perform online analytical processing (OLAP) to facilitate web-based information. In this study generated BI application development framework with Model-View-Controller (MVC) architecture and OLAP operations are built using the dynamic query generation, PivotTable, and HighChart to present information about PNS, CPNS, Retirement, Kenpa and Presence

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39

Osmany, S. A., F. Herzel, K. Schmalz, and W. Winkler. "Phase noise and jitter modeling for fractional-N PLLs." Advances in Radio Science 5 (June 13, 2007): 313–20. http://dx.doi.org/10.5194/ars-5-313-2007.

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Abstract. We present an analytical phase noise model for fractional-N phase-locked loops (PLL) with emphasis on integrated RF synthesizers in the GHz range. The noise of the crystal reference, the voltage-controlled oscillator (VCO), the loop filter, the charge pump, and the sigma-delta modulator (SDM) is filtered by the PLL operation. We express the rms phase error (jitter) in terms of phase noise of the reference, the VCO phase noise and the third-order loop filter parameters. In addition, we consider OFDM systems, where the PLL phase noise is reduced by digital signal processing after down-conversion of the RF signal to baseband. The rms phase error is discussed as a function of the loop parameters. Our model drastically simplifies the noise optimization of the PLL loop dynamics.

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40

Hudson, Thomas, Patrick van Meurs, and Mark Peletier. "Atomistic origins of continuum dislocation dynamics." Mathematical Models and Methods in Applied Sciences 30, no. 13 (December 15, 2020): 2557–618. http://dx.doi.org/10.1142/s0218202520500505.

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This paper focuses on the connections between four stochastic and deterministic models for the motion of straight screw dislocations. Starting from a description of screw dislocation motion as interacting random walks on a lattice, we prove explicit estimates of the distance between solutions of this model, an SDE system for the dislocation positions, and two deterministic mean-field models describing the dislocation density. The proof of these estimates uses a collection of various techniques in analysis and probability theory, including a novel approach to establish propagation-of-chaos on a spatially discrete model. The estimates are non-asymptotic and explicit in terms of four parameters: the lattice spacing, the number of dislocations, the dislocation core size, and the temperature. This work is a first step in exploring this parameter space with the ultimate aim to connect and quantify the relationships between the many different dislocation models present in the literature.

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41

Guo, Yongbo, and Fansheng Wang. "Multi Body Dynamic Equations of Belt Conveyor and the Reasonable Starting Mode." Symmetry 12, no. 9 (September 10, 2020): 1489. http://dx.doi.org/10.3390/sym12091489.

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Based on the rigid finite element method and multibody dynamics, a discrete model of a flexible conveyor belt considering the material viscoelasticity is established. RFE (rigid finite element) and SDE (spring damping element) are used to describe the rigidity and flexibility of a conveyor belt. The dynamic differential equations of the RFE are derived by using Lagrange’s equation of the second kind of the non-conservative system. The generalized elastic potential capacity and generalized dissipation force of the SDE are considered. The forward recursive formula is used to construct the conveyor belt model. The validity of dynamic equations of conveyor belt is verified by field test. The starting mode of the conveyor is simulated by the model.

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42

Nguyen Thanh, Tuu, Van Pham Dang Tri, Seungdo Kim, Thuy Nguyen Phuong, Thuy Lam Mong, and Phong Vuong Tuan. "A Subregional Model of System Dynamics Research on Surface Water Resource Assessment for Paddy Rice Production under Climate Change in the Vietnamese Mekong Delta." Climate 8, no. 3 (March 12, 2020): 41. http://dx.doi.org/10.3390/cli8030041.

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Effective water management plays an important role in socioeconomic development in the Vietnamese Mekong Delta (VMD). The impacts of climate change and human activities (that is, domestic consumption and industrial and agricultural activities) vary in different subregions of the delta. In order to provide intersectoral data for determining the significantly impacted subregions of the VMD, the present study simulated interactions between local climatic patterns, human activities, and water resources using a system dynamics modeling (SDM) approach with each subregion as an agent of the developed model. The average rainfall and temperature of 121 subregions in the VMD were collected during 1982–2012, and the future changes of climate by provinces were based on the Representative Concentration Pathways (RCP) scenarios (RCP4.5 and RCP8.5) by the end of 21st century. The assessment was based on the levels of impact of various factors, including (1) water consumption, (2) differences between evapotranspiration and rainfall, and (3) spatial distribution of salinity intrusion over the delta scale. In the coastal areas, as well as the central and upstream areas, water resources were projected to be affected by environmental changes, whereas the former, characterized by the lack of surface freshwater, would be affected at a greater scale during the dry season. Besides, the sea level rise would lead to an increase in negative impacts in the eastern coastal areas, suggesting that water-saving techniques should be applied not only for agriculture, but also for industry and domestic water consumption during the dry season. In addition, the south subregions (that is, the western subregions of the Hau River except for An Giang) were likely to be flooded due to the simulated high rainfall and seasonal rises of sea level during the wet season. Therefore, the alternative forms of settlement and livelihood should be considered toward balance management with changing delta dynamics.

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43

Liu, Xu, Wei Liu, and Yunfei Zhao. "Unsteady Vibration Aerodynamic Modeling and Evaluation of Dynamic Derivatives Using Computational Fluid Dynamics." Mathematical Problems in Engineering 2015 (2015): 1–15. http://dx.doi.org/10.1155/2015/813462.

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Unsteady aerodynamic system modeling is widely used to solve the dynamic stability problems encountering aircraft design. In this paper, single degree-of-freedom (SDF) vibration model and forced simple harmonic motion (SHM) model for dynamic derivative prediction are developed on the basis of modified Etkin model. In the light of the characteristics of SDF time domain solution, the free vibration identification methods for dynamic stability parameters are extended and applied to the time domain numerical simulation of blunted cone calibration model examples. The dynamic stability parameters by numerical identification are no more than 0.15% deviated from those by experimental simulation, confirming the correctness of SDF vibration model. The acceleration derivatives, rotary derivatives, and combination derivatives of Army-Navy Spinner Rocket are numerically identified by using unsteady N-S equation and solving different SHV patterns. Comparison with the experimental result of Army Ballistic Research Laboratories confirmed the correctness of the SHV model and dynamic derivative identification. The calculation result of forced SHM is better than that by the slender body theory of engineering approximation. SDF vibration model and SHM model for dynamic stability parameters provide a solution to the dynamic stability problem encountering aircraft design.

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44

Giribone, Pier Giuseppe, and Roberto Revetria. "Certificate pricing using Discrete Event Simulations and System Dynamics theory." Risk Management Magazine 16, no. 2 (August 18, 2021): 75–93. http://dx.doi.org/10.47473/2020rmm0092.

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The study proposes an innovative application of Discrete Event Simulations (DES) and System Dynamics (SD) theory to the pricing of a certain kind of certificates very popular among private investors and, more generally, in the context of wealth management. The paper shows how numerical simulation software mainly used in traditional engineering, such as industrial and mechanical engineering, can be successfully adapted to the risk analysis of structured financial products. The article can be divided into three macro-sections: in the first part a synthetic overview of the most widespread option pricing models in the quantitative finance branch is given to the readers together with the fundamental technical-instrumental background of the implemented DES and SD simulator. After dealing with some of the most popular models adopted for Equity and Equity index options, which are the most common underlying assets for the certificates structuring, we move, in the second part, to describe how the mathematical models can be integrated into a general simulation environment able to provide both DES and SD extensively used in the engineering field. The core stochastic differential equation (SDE) will therefore be translated, together with all its input parameters, into a visual block model which allows an immediate quantitative analysis of how market parameters and the other model variables can change over time. The possibility for the structurer to observe how the variables evolve day-by-day gives a strong sensitivity to evaluate how the price and the associated risk measures can be directly affected. The third part of the study compares the results obtained from the simulator designed by the authors with the more traditional pricing approaches, which consist in programming Matlab® codes for the numerical integration of the core stochastic dynamics through a Euler-Maruyama scheme. The comparison includes a price check using the Bloomberg® DLIB pricing module and a check directly against the valuation provided by the counterparty. In this section, real market cases will therefore be examined with a complete quantitative analysis of two of the most widespread categories of certificates in wealth management: Multi-asset Barrier Reverse Convertible with Issuer Callability and Multi-asset Express Certificate with conditional memory fixed coupon.

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45

Infante, Saba, Luis Sanchez, and Aracelis Hernandez. "Stochastic models to estimate population dynamics." Statistics, Optimization & Information Computing 8, no. 1 (February 17, 2020): 136–52. http://dx.doi.org/10.19139/soic-2310-5070-488.

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The growth dynamics that a population follows is mainly due to births, deaths or migrations, each of thesephenomena is affected by other factors such as public health, birth control, work sources, economy, safety and conditions of quality of life in neighboring countries, among many others. In this paper is proposed two statistical models based on a system of stochastic differential equations (SDE) that model the dynamics of population growth, and three computational algorithms that allow the generation of probability distribution samples in high dimensions, in models that have non-linear structures and that are useful for making inferences. The algorithms allow to estimate simultaneously states solutions and parameters in SDE models. The interpretation of the parameters is important because they are related to the variables of growth, mortality, migration, physical-chemical conditions of the environment, among other factors. The algorithms are illustrated using real data from a sector of the population of the Republic of Ecuador, and are compared with the results obtained with the models used by theWorld Bank for the same data, which shows that stochastic models Proposals based on an SDE more adequately and reliably adjust the dynamics of demographic randomness, sampling errors and environmental randomness in comparison with the deterministic models used by the World Bank. It is observed that the population grows year by year and seems to have a definite tendency; that is, a clearly growing behavior is seen. To measure the relative success of the algorithms, the relative error was estimated, obtaining small percentage errors.

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46

Pfaffenbichler, Paul, Günter Emberger, and Simon Shepherd. "A system dynamics approach to land use transport interaction modelling: the strategic model MARS and its application." System Dynamics Review 26, no. 3 (July 2010): 262–82. http://dx.doi.org/10.1002/sdr.451.

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47

Lynn, Barry H., Alexander P. Khain, Jimy Dudhia, Daniel Rosenfeld, Andrei Pokrovsky, and Axel Seifert. "Spectral (Bin) Microphysics Coupled with a Mesoscale Model (MM5). Part I: Model Description and First Results." Monthly Weather Review 133, no. 1 (January 1, 2005): 44–58. http://dx.doi.org/10.1175/mwr-2840.1.

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Abstract Considerable research investments have been made to improve the accuracy of forecasting precipitation systems in cloud-resolving, mesoscale atmospheric models. Yet, despite a significant improvement in model grid resolution and a decrease in initial condition uncertainty, the accurate prediction of precipitation amount and distribution still remains a difficult problem. Now, the development of a fast version of spectral (bin) microphysics (SBM Fast) offers significant potential for improving the description of precipitation-forming processes in mesoscale atmospheric models. The SBM Fast is based on solving a system of equations for size distribution functions for water drops and three types of ice crystals (plates, columns, and dendrites), as well as snowflakes, graupel, and hail/frozen drops. Ice processes are represented by three size distributions, instead of six in the original SBM code. The SBM uses first principles to simulate microphysical processes such as diffusional growth and collision. A budget for aerosols is used to obtain the spectrum of condensation nuclei, which is used to obtain the initial drop spectrum. Hence, SBM allows one to take into account aerosol effects on precipitation, and corresponding cloud effects on the atmospheric aerosol concentration and distribution. SBM Fast has been coupled with the three-dimensional fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5), which allows SBM Fast to simulate microphysics within a realistic, time-varying mesoscale environment. This paper describes the first three-dimensional SBM mesoscale model and presents results using 1-km resolution to simulate initial development of a cloud system over Florida on 27 July 1991. The focus is on initial cloud development along the west coast, just prior to sea-breeze formation. The results indicate that the aerosol concentration had a very important impact on cloud dynamics, microphysics, and rainfall. Vertical cross sections of clouds obtained using SBM Fast are compared to those from a version of the “Reisner2” bulk-parameterization scheme that uses the Kessler autoconversion formula. The results show that this version of “Reisner2” produced vertically upright clouds that progressed very quickly from initial cloud formation to raindrop formation. In contrast, clouds obtained using SBM were relatively long lasting with greater production of stratiform clouds.

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48

Sharma, Shambhu N., and H. Parthasarathy. "Dynamics of a stochastically perturbed two-body problem." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 463, no. 2080 (January 16, 2007): 979–1003. http://dx.doi.org/10.1098/rspa.2006.1801.

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In classical mechanics, the two-body problem has been well studied. The governing equations form a system of two-coupled second-order nonlinear differential equations for the radial and angular coordinates. The perturbation induced by the astronomical disturbance like ‘dust’ is normally not considered in the orbit dynamics. Distributed dust produces an additional random force on the orbiting particle, which can be modelled as a random force having ‘Gaussian statistics’. The estimation of accurate positioning of the orbiting particle is not possible without accounting for the stochastic perturbation felt by the orbiting particle. The objective of this paper is to use the stochastic differential equation (SDE) formalism to study the effect of such disturbances on the orbiting body. Specifically, in this paper, we linearize SDEs about the mean of the state vector. The linearization operation performed above, transforms the system of SDEs into another system of SDEs that resembles a bilinear system, as described in signal processing and control literature. However, the mean trajectory of the resulting bilinear stochastic differential model does not preserve the perturbation effect felt by the orbiting particle; only the variance trajectory includes the perturbation effect. For this reason, the effectiveness of the dust-perturbed model is examined on the basis of the bilinear and second-order approximations of the system nonlinearity . The bilinear and second-order approximations of the system nonlinearity allow substantial simplifications for the numerical implementation and preserve some of the properties of the original stochastically perturbed model. Most notably, this paper reveals that the Brownian motion process is accurate to model and study the effect of dust perturbation on the orbiting particle. In addition, analytical findings are supported with finite difference method-based numerical simulations.

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49

Narayan, Rajiv, Ayla Ergün, and Kamal Sen. "Delayed Inhibition in Cortical Receptive Fields and the Discrimination of Complex Stimuli." Journal of Neurophysiology 94, no. 4 (October 2005): 2970–75. http://dx.doi.org/10.1152/jn.00144.2005.

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Although auditory cortex is thought to play an important role in processing complex natural sounds such as speech and animal vocalizations, the specific functional roles of cortical receptive fields (RFs) remain unclear. Here, we study the relationship between a behaviorally important function: the discrimination of natural sounds and the structure of cortical RFs. We examine this problem in the model system of songbirds, using a computational approach. First, we constructed model neurons based on the spectral temporal RF (STRF), a widely used description of auditory cortical RFs. We focused on delayed inhibitory STRFs, a class of STRFs experimentally observed in primary auditory cortex (ACx) and its analog in songbirds (field L), which consist of an excitatory subregion and a delayed inhibitory subregion cotuned to a characteristic frequency. We quantified the discrimination of birdsongs by model neurons, examining both the dynamics and temporal resolution of discrimination, using a recently proposed spike distance metric (SDM). We found that single model neurons with delayed inhibitory STRFs can discriminate accurately between songs. Discrimination improves dramatically when the temporal structure of the neural response at fine timescales is considered. When we compared discrimination by model neurons with and without the inhibitory subregion, we found that the presence of the inhibitory subregion can improve discrimination. Finally, we modeled a cortical microcircuit with delayed synaptic inhibition, a candidate mechanism underlying delayed inhibitory STRFs, and showed that blocking inhibition in this model circuit degrades discrimination.

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50

Capelo, Carlos, and João Ferreira Dias. "A system dynamics-based simulation experiment for testing mental model and performance effects of using the balanced scorecard." System Dynamics Review 25, no. 1 (January 2009): 1–34. http://dx.doi.org/10.1002/sdr.413.

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