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System Dynamics
System dynamics (SD) is an approach to understanding the nonlinear behaviour of complex systems over time using stocks, flows, internal feedback loops, table functions and time delays. Overview System dynamics is a methodology and mathematical modeling technique to frame, understand, and discuss complex issues and problems. Originally developed in the 1950s to help corporate managers improve their understanding of industrial processes, SD is currently being used throughout the public and private sector for policy analysis and design. Convenient graphical user interface (GUI) system dynamics software developed into user friendly versions by the 1990s and have been applied to diverse systems. SD models solve the problem of simultaneity (mutual causation) by updating all variables in small time increments with positive and negative feedbacks and time delays structuring the interactions and control. The best known SD model is probably the 1972 '' The Limits to Growth''. This model ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adoption SFD ANI S
Adoption is a process whereby a person assumes the parenting of another, usually a child, from that person's biological or legal parent or parents. Legal adoptions permanently transfer all rights and responsibilities, along with filiation, from the biological parents to the adoptive parents. Unlike guardianship or other systems designed for the care of the young, adoption is intended to effect a permanent change in status and as such requires societal recognition, either through legal or religious sanction. Historically, some societies have enacted specific laws governing adoption, while others used less formal means (notably contracts that specified inheritance rights and parental responsibilities without an accompanying transfer of filiation). Modern systems of adoption, arising in the 20th century, tend to be governed by comprehensive statutes and regulations. History Antiquity ;Adoption for the well-born While the modern form of adoption emerged in the United States, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DYNAMO (programming Language)
DYNAMO (DYNAmic MOdels) is a simulation language and accompanying graphical notation developed within the system dynamics analytical framework. It was originally for industrial dynamics but was soon extended to other applications, including population and resource studies and urban planning. DYNAMO was initially developed under the direction of Jay Wright Forrester in the late 1950s, by Dr. Phyllis Fox, Alexander L. Pugh III, Grace Duren, and others at the M.I.T. Computation Center. DYNAMO was used for the system dynamics simulations of global resource depletion reported in the Club of Rome's Limits to Growth, but has since fallen into disuse. Beginnings In 1958, Forrester unwittingly instigated DYNAMO's development when he asked an MIT staff programmer to compute needed solutions to some equations, for a Harvard Business Review paper he was writing about industrial dynamics. The programmer, Richard Bennett, chose to implement a system (SIMPLE - "Simulation of Industrial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discrete Time
In mathematical dynamics, discrete time and continuous time are two alternative frameworks within which variables that evolve over time are modeled. Discrete time Discrete time views values of variables as occurring at distinct, separate "points in time", or equivalently as being unchanged throughout each non-zero region of time ("time period")—that is, time is viewed as a discrete variable. Thus a non-time variable jumps from one value to another as time moves from one time period to the next. This view of time corresponds to a digital clock that gives a fixed reading of 10:37 for a while, and then jumps to a new fixed reading of 10:38, etc. In this framework, each variable of interest is measured once at each time period. The number of measurements between any two time periods is finite. Measurements are typically made at sequential integer values of the variable "time". A discrete signal or discrete-time signal is a time series consisting of a sequence of quantities ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comparison Of System Dynamics Software
This is a comparison of various aspects of software offering system dynamics features: ''Due to concerns over commercial postings on the system dynamics main topic, commercial hyperlinks are specifically NOT active on this list.'' Table of system dynamics software :L.Graphing library MxGraph is licensed separately under paid commercial licence See also * List of computer simulation software References {{reflist System dynamics System dynamics (SD) is an approach to understanding the nonlinear behaviour of complex systems over time using stocks, flows, internal feedback loops, table functions and time delays. Overview System dynamics is a methodology and mathematica ... Systems theory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spreadsheet
A spreadsheet is a computer application for computation, organization, analysis and storage of data in tabular form. Spreadsheets were developed as computerized analogs of paper accounting worksheets. The program operates on data entered in cells of a table. Each cell may contain either numeric or text data, or the results of formulas that automatically calculate and display a value based on the contents of other cells. The term ''spreadsheet'' may also refer to one such electronic document. Spreadsheet users can adjust any stored value and observe the effects on calculated values. This makes the spreadsheet useful for "what-if" analysis since many cases can be rapidly investigated without manual recalculation. Modern spreadsheet software can have multiple interacting sheets and can display data either as text and numerals or in graphical form. Besides performing basic arithmetic and mathematical functions, modern spreadsheets provide built-in functions for common financial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adoption SFD
Adoption is a process whereby a person assumes the parenting of another, usually a child, from that person's biological or legal parent or parents. Legal adoptions permanently transfer all rights and responsibilities, along with filiation, from the biological parents to the adoptive parents. Unlike guardianship or other systems designed for the care of the young, adoption is intended to effect a permanent change in status and as such requires societal recognition, either through legal or religious sanction. Historically, some societies have enacted specific laws governing adoption, while others used less formal means (notably contracts that specified inheritance rights and parental responsibilities without an accompanying transfer of filiation). Modern systems of adoption, arising in the 20th century, tend to be governed by comprehensive statutes and regulations. History Antiquity ;Adoption for the well-born While the modern form of adoption emerged in the United States, for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simple Stock And Flow Diagram
Simple or SIMPLE may refer to: *Simplicity, the state or quality of being simple Arts and entertainment * ''Simple'' (album), by Andy Yorke, 2008, and its title track * "Simple" (Florida Georgia Line song), 2018 * "Simple", a song by Johnny Mathis from the 1984 album '' A Special Part of Me'' * "Simple", a song by Collective Soul from the 1995 album ''Collective Soul'' * "Simple", a song by Katy Perry from the 2005 soundtrack to ''The Sisterhood of the Traveling Pants'' * "Simple", a song by Khalil from the 2017 album ''Prove It All'' * "Simple", a song by Kreesha Turner from the 2008 album '' Passion'' * "Simple", a song by Ty Dolla Sign from the 2017 album '' Beach House 3'' deluxe version * ''Simple'' (video game series), budget-priced console games Businesses and organisations * Simple (bank), an American direct bank * SIMPLE Group, a consulting conglomeration based in Gibraltar * Simple Shoes, an American footwear brand * Simple Skincare, a British brand of so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stock And Flow
Economics, business, accounting, and related fields often distinguish between quantities that are stocks and those that are flows. These differ in their units of measurement. A ''stock'' is measured at one specific time, and represents a quantity existing at that point in time (say, December 31, 2004), which may have accumulated in the past. A ''flow'' variable is measured over an interval of time. Therefore, a flow would be measured ''per unit of time'' (say a year). Flow is roughly analogous to rate or speed in this sense. For example, U.S. nominal gross domestic product refers to a total number of dollars spent over a time period, such as a year. Therefore, it is a flow variable, and has units of dollars/year. In contrast, the U.S. nominal capital stock is the total value, in dollars, of equipment, buildings, and other real productive assets in the U.S. economy, and has units of dollars. The diagram provides an intuitive illustration of how the ''stock'' of capital currently ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adoption CLD
Adoption is a process whereby a person assumes the parenting of another, usually a child, from that person's biological or legal parent or parents. Legal adoptions permanently transfer all rights and responsibilities, along with filiation, from the biological parents to the adoptive parents. Unlike guardianship or other systems designed for the care of the young, adoption is intended to effect a permanent change in status and as such requires societal recognition, either through legal or religious sanction. Historically, some societies have enacted specific laws governing adoption, while others used less formal means (notably contracts that specified inheritance rights and parental responsibilities without an accompanying transfer of filiation). Modern systems of adoption, arising in the 20th century, tend to be governed by comprehensive statutes and regulations. History Antiquity ;Adoption for the well-born While the modern form of adoption emerged in the United States, for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Causal Loop Diagram
A causal loop diagram (CLD) is a causal diagram that aids in visualizing how different variables in a system are causally interrelated. The diagram consists of a set of words and arrows. Causal loop diagrams are accompanied by a narrative which describes the causally closed situation the CLD describes. Closed loops, or causal feedback loops, in the diagram are very important features of CLDs. The words with arrows coming in and out represent variables, or quantities whose value changes over time and the links represent a causal relationship between the two variables (i.e., they do not represent a material flow). A link marked + indicates a positive relation where an increase in the causal variable leads, all else equal, to an increase in the effect variable, or a decrease in the causal variable leads, all else equal, to a decrease in the effect variable. A link marked - indicates a negative relation where an increase in the causal variable leads, all else equal, to a decrease in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World Dynamics
Jay Wright Forrester (July 14, 1918 – November 16, 2016) was a pioneering American computer engineer and systems scientist. He is credited with being one of the inventors of magnetic core memory, the predominant form of random-access computer memory during the most explosive years of digital computer development (between 1955 and 1975). It was part of a family of related technologies which bridged the gap between vacuum tubes and semiconductors by exploiting the magnetic properties of materials to perform switching and amplification. He is also believed to have created the first animation in the history of computer graphics, a "jumping ball" on an oscilloscope. Later, he was a professor at the MIT Sloan School of Management, where he introduced the Forrester effect describing fluctuations in supply chains, and is credited as the founder of system dynamics, which deals with the simulation of interactions between objects in dynamic systems and is most often applied to res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carrying Capacity
The carrying capacity of an environment is the maximum population size of a biological species that can be sustained by that specific environment, given the food, habitat, water, and other resources available. The carrying capacity is defined as the environment's maximal load, which in population ecology corresponds to the population equilibrium, when the number of deaths in a population equals the number of births (as well as immigration and emigration). The effect of carrying capacity on population dynamics is modelled with a logistic function. Carrying capacity is applied to the maximum population an environment can support in ecology, agriculture and fisheries. The term carrying capacity has been applied to a few different processes in the past before finally being applied to population limits in the 1950s. The notion of carrying capacity for humans is covered by the notion of sustainable population. At the global scale, scientific data indicates that humans are living bey ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
