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The doubling time is the period of time required for a quantity to double in size or value. It is applied to population growth, inflation, resource extraction, consumption of goods, compound interest, the volume of malignant tumours, and many other things that tend to grow over time. When the relative growth rate (not the absolute growth rate) is constant, the quantity undergoes exponential growth and has a constant doubling time or period, which can be calculated directly from the growth rate.
This time can be calculated by dividing the natural logarithm of 2 by the exponent of growth, or approximated by dividing 70 by the percentage growth rate[1] (more roughly but roundly, dividing 72; see the rule of 72 for details and a derivation of this formula).
The doubling time is a characteristic unit (a natural unit of scale) for the exponential growth equation, and its converse for exponential decay is the half-life.
Peter Senge was born in. Learning organization and systems thinking. That are able to adapt quickly and effectively will be able to excel in their field. TECHCOMM 7047NA - Systems Fundamentals. Be assisted by reading various parts of Thinking in Systems: A Primer (D Meadows) 2. With Systems, Donella Meadows. The doubling time is the period of time required for a quantity to double in size or value. It is applied to population growth, inflation, resource extraction, consumption of goods, compound interest, the volume of malignant tumours, and many other things that tend to grow over time. Resilience is a measure of a systemâs ability to survive and persist within a variable environment. The opposite of resilience is brittleness or rigidity. Resilience arises from a rich structure of many feedback loops that can work in different ways to restore a system even after a large perturbation.
For example, given Canada's net population growth of 0.9% in the year 2006, dividing 70 by 0.9 gives an approximate doubling time of 78 years. Thus if the growth rate remains constant, Canada's population would double from its 2006 figure of 33 million to 66 million by 2084.
History[edit]
See more What others are saying 'No pressure internal communicators! Open and honest communication in a company is seen to have the biggest potential impact on employee morale.' In finance, the rule of 72, the rule of 70 and the rule of 69.3 are methods for estimating an investment's doubling time. The rule number (e.g., 72) is divided by the.
The notion of doubling time dates to interest on loans in Babylonian mathematics. Clay tablets from circa 2000 BCE include the exercise 'Given an interest rate of 1/60 per month (no compounding), come the doubling time.' This yields an annual interest rate of 12/60 = 20%, and hence a doubling time of 100% growth/20% growth per year = 5 years.[2][3] Further, repaying double the initial amount of a loan, after a fixed time, was common commercial practice of the period: a common Assyrian loan of 1900 BCE consisted of loaning 2 minas of gold, getting back 4 in five years,[2] and an Egyptian proverb of the time was 'If wealth is placed where it bears interest, it comes back to you redoubled.'[2][4]
Examination[edit]
Examining the doubling time can give a more intuitive sense of the long-term impact of growth than simply viewing the percentage growth rate
For a constant growth rate of r% within time t, the formula for the doubling time Td is given by
Some doubling times calculated with this formula are shown in this table.
Simple doubling time formula:
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For example, with an annual growth rate of 4.8% the doubling time is 14.78 years, and a doubling time of 10 years corresponds to a growth rate between 7% and 7.5% (actually about 7.18%).
When applied to the constant growth in consumption of a resource, the total amount consumed in one doubling period equals the total amount consumed in all previous periods.This enabled US President Jimmy Carter to note in a speech in 1977 that in each of the previous two decades the world had used more oil than in all of previous history (The roughly exponential growth in world oil consumption between 1950 and 1970 had a doubling period of under a decade).
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Given two measurements of a growing quantity, q1 at time t1 and q2 at time t2, and assuming a constant growth rate, you can calculate the doubling time as
Where is it useful?[edit]
A constant relative growth rate means simply that the increase per unit time is proportional to the current quantity, i.e. the addition rate per unit amount is constant. It naturally occurs when the existing material generates or is the main determinant of new material. For example, population growth in virgin territory, or fractional-reserve banking creating inflation. With unvarying growth the doubling calculation may be applied for many doubling periods or generations.
In practice eventually other constraints become important, exponential growth stops and the doubling time changes or becomes inapplicable. Limited food supply or other resources at high population densities will reduce growth, or needing a wheel-barrow full of notes to buy a loaf of bread will reduce the acceptance of paper money. While using doubling times is convenient and simple, we should not apply the idea without considering factors which may affect future growth. In the 1950s Canada's population growth rate was over 3% per year, so extrapolating the current growth rate of 0.9% for many decades (implied by the doubling time) is unjustified unless we have examined the underlying causes of the growth and determined they will not be changing significantly over that period.
Related concepts[edit]
The equivalent concept to doubling time for a material undergoing a constant negative relative growth rate or exponential decay is the half-life.
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The equivalent concept in base-e is e-folding.
Graphs comparing doubling times and half lives of exponential growths (bold lines) and decay (faint lines), and their 70/t and 72/t approximations. In the SVG version, hover over a graph to highlight it and its complement.
Cell culture doubling time[edit]
Cell doubling time can be calculated in the following way using growth rate (amount of doubling in one unit of time)
Growth rate:
or
Doubling time:
The following is the known doubling time for the following cells:
See also[edit]References[edit]
External links[edit]
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Doubling_time&oldid=903549392'
(Redirected from Computer information systems)
Information systems (IS) are formal, sociotechnical, organizational systems designed to collect, process, store, and distribute information.[1] In a sociotechnical perspective, information systems are composed by four components: task, people, structure (or roles), and technology.[2]
A computer information system is a system composed of people and computers that processes or interprets information.[3][4][5][6] The term is also sometimes used in more restricted senses to refer to only the software used to run a computerized database or to refer to only a computer system.
Information Systems is an academic study of systems with a specific reference to information and the complementary networks of hardware and software that people and organizations use to collect, filter, process, create and also distribute data. An emphasis is placed on an information system having a definitive boundary, users, processors, storage, inputs, outputs and the aforementioned communication networks.[7]
Any specific information system aims to support operations, management and decision-making.[8][9] An information system is the information and communication technology (ICT) that an organization uses, and also the way in which people interact with this technology in support of business processes.[10]
Some authors make a clear distinction between information systems, computer systems, and business processes. Information systems typically include an ICT component but are not purely concerned with ICT, focusing instead on the end use of information technology. Information systems are also different from business processes. Information systems help to control the performance of business processes.[11]
Alter[12][13] argues for advantages of viewing an information system as a special type of work system. A work system is a system in which humans or machines perform processes and activities using resources to produce specific products or services for customers. An information system is a work system whose activities are devoted to capturing, transmitting, storing, retrieving, manipulating and displaying information.[14]
As such, information systems inter-relate with data systems on the one hand and activity systems on the other. An information system is a form of communication system in which data represent and are processed as a form of social memory. An information system can also be considered a semi-formal language which supports human decision making and action.
Information systems are the primary focus of study for organizational informatics.[15]
Overview[edit]
Silver et al. (1995) provided two views on IS that includes software, hardware, data, people, and procedures.[16] Zheng provided another system view of information system which also adds processes and essential system elements like environment, boundary, purpose, and interactions.
The Association for Computing Machinery defines 'Information systems specialists [as] focus[ing] on integrating information technology solutions and business processes to meet the information needs of businesses and other enterprises.'[17]
There are various types of information systems, for example: transaction processing systems, decision support systems, knowledge management systems, learning management systems, database management systems, and office information systems. Critical to most information systems are information technologies, which are typically designed to enable humans to perform tasks for which the human brain is not well suited, such as: handling large amounts of information, performing complex calculations, and controlling many simultaneous processes.
Sketchbook pro windows 10 vs desktop. Information technologies are a very important and malleable resource available to executives.[18] Many companies have created a position of chief information officer (CIO) that sits on the executive board with the chief executive officer (CEO), chief financial officer (CFO), chief operating officer (COO), and chief technical officer (CTO). The CTO may also serve as CIO, and vice versa. The chief information security officer (CISO) focuses on information security management.
The six components that must come together in order to produce an information system are: (Information systems are organizational procedures and do not need a computer or software, this data is erroneous) (IE, an accounting system in the 1400s using ledger and ink utilizes an information system)
Data is the bridge between hardware and people. This means that the data we collect is only data until we involve people. At that point, data is now information.
Types of information system[edit]
A four level hierarchy
The 'classic' view of Information systems found in textbooks[19] in the 1980s was a pyramid of systems that reflected the hierarchy of the organization, usually transaction processing systems at the bottom of the pyramid, followed by management information systems, decision support systems, and ending with executive information systems at the top. Although the pyramid model remains useful since it was first formulated, a number of new technologies have been developed and new categories of information systems have emerged, some of which no longer fit easily into the original pyramid model.
Some examples of such systems are:
A computer(-based) information system is essentially an IS using computer technology to carry out some or all of its planned tasks. The basic components of computer-based information systems are:
The first four components (hardware, software, database, and network) make up what is known as the information technology platform.Information technology workers could then use these components to create information systems that watch over safety measures, risk and the management of data. These actions are known as information technology services.[20]
Certain information systems support parts of organizations, others support entire organizations, and still others, support groups of organizations. Recall that each department or functional area within an organization has its own collection of application programs or information systems. These functional area information systems (FAIS) are supporting pillars for more general IS namely, business intelligence systems and dashboards[citation needed]. As the name suggests, each FAIS support a particular function within the organization, e.g.: accounting IS, finance IS, production-operation management (POM) IS, marketing IS, and human resources IS. In finance and accounting, managers use IT systems to forecast revenues and business activity, to determine the best sources and uses of funds, and to perform audits to ensure that the organization is fundamentally sound and that all financial reports and documents are accurate. Other types of organizational information systems are FAIS, Transaction processing systems, enterprise resource planning, office automation system, management information system, decision support system, expert system, executive dashboard, supply chain management system, and electronic commerce system. Dashboards are a special form of IS that support all managers of the organization. They provide rapid access to timely information and direct access to structured information in the form of reports. Expert systems attempt to duplicate the work of human experts by applying reasoning capabilities, knowledge, and expertise within a specific domain.
Information system development[edit]
Information technology departments in larger organizations tend to strongly influence the development, use, and application of information technology in the business.A series of methodologies and processes can be used to develop and use an information system. Many developers use a systems engineering approach such as the system development life cycle (SDLC), to systematically develop an information system in stages. The stages of the system development lifecycle are planning, system analysis and requirements, system design, development, integration and testing, implementation and operations and maintenance. Recent research aims at enabling[21] and measuring[22] the ongoing, collective development of such systems within an organization by the entirety of human actors themselves.An information system can be developed in house (within the organization) or outsourced. This can be accomplished by outsourcing certain components or the entire system.[23] A specific case is the geographical distribution of the development team (offshoring, global information system).
A computer-based information system, following a definition of Langefors,[24] is a technologically implemented medium for:
Geographic information systems, land information systems, and disaster information systems are examples of emerging information systems, but they can be broadly considered as spatial information systems.System development is done in stages which include:
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As an academic discipline[edit]
The field of study called information systems encompasses a variety of topics including systems analysis and design, computer networking, information security, database management and decision support systems. Information management deals with the practical and theoretical problems of collecting and analyzing information in a business function area including business productivity tools, applications programming and implementation, electronic commerce, digital media production, data mining, and decision support. Communications and networking deals with the telecommunication technologies.Information systems bridges business and computer science using the theoretical foundations of information and computation to study various business models and related algorithmic processes [26] on building the IT systems [27][28] within a computer science discipline.[29][30][31][32][33][34][35][36][37][38][39][40][41]Computer information system(s) (CIS) is a field studying computers and algorithmic processes, including their principles, their software and hardware designs, their applications, and their impact on society,[42][43][44] whereas IS emphasizes functionality over design.[45]
Several IS scholars have debated the nature and foundations of Information Systems which have its roots in other reference disciplines such as Computer Science, Engineering, Mathematics, Management Science, Cybernetics, and others.[46][47][48][49] Information systems also can be defined as a collection of hardware, software, data, people and procedures that work together to produce quality information.
Donella Meadows PdfDifferentiating IS from related disciplines[edit]
Information Systems relationship to Information Technology, Computer Science, Information Science, and Business.
Similar to computer science, other disciplines can be seen as both related and foundation disciplines of IS. The domain of study of IS involves the study of theories and practices related to the social and technological phenomena, which determine the development, use, and effects of information systems in organization and society.[50] But, while there may be considerable overlap of the disciplines at the boundaries, the disciplines are still differentiated by the focus, purpose, and orientation of their activities.[51]
In a broad scope, the term Information Systems is a scientific field of study that addresses the range of strategic, managerial, and operational activities involved in the gathering, processing, storing, distributing, and use of information and its associated technologies in society and organizations.[51] The term information systems is also used to describe an organizational function that applies IS knowledge in industry, government agencies, and not-for-profit organizations.[51]Information Systems often refers to the interaction between algorithmic processes and technology. This interaction can occur within or across organizational boundaries. An information system is the technology an organization uses and also the way in which the organizations interact with the technology and the way in which the technology works with the organization's business processes. Information systems are distinct from information technology (IT) in that an information system has an information technology component that interacts with the processes' components.
One problem with that approach is that it prevents the IS field from being interested in non-organizational use of ICT, such as in social networking, computer gaming, mobile personal usage, etc. A different way of differentiating the IS field from its neighbours is to ask, 'Which aspects of reality are most meaningful in the IS field and other fields?'[52] This approach, based on philosophy, helps to define not just the focus, purpose and orientation, but also the dignity, destiny and, responsibility of the field among other fields.International Journal of Information Management, 30, 13-20.
Career pathways[edit]
Information Systems workers enter a number of different careers:
There is a wide variety of career paths in the information systems discipline. 'Workers with specialized technical knowledge and strong communications skills will have the best prospects. Workers with management skills and an understanding of business practices and principles will have excellent opportunities, as companies are increasingly looking to technology to drive their revenue.'[53]
Information technology is important to the operation of contemporary businesses, it offers many employment opportunities. The information systems field includes the people in organizations who design and build information systems, the people who use those systems, and the people responsible for managing those systems.The demand for traditional IT staff such as programmers, business analysts, systems analysts, and designer is significant. Many well-paid jobs exist in areas of Information technology. At the top of the list is the chief information officer (CIO).
The CIO is the executive who is in charge of the IS function. In most organizations, the CIO works with the chief executive officer (CEO), the chief financial officer (CFO), and other senior executives. Therefore, he or she actively participates in the organization's strategic planning process.
Research[edit]
Information systems research is generally interdisciplinary concerned with the study of the effects of information systems on the behaviour of individuals, groups, and organizations.[54][55] Hevner et al. (2004)[56] categorized research in IS into two scientific paradigms including behavioural science which is to develop and verify theories that explain or predict human or organizational behavior and design science which extends the boundaries of human and organizational capabilities by creating new and innovative artifacts.
Salvatore March and Gerald Smith[57] proposed a framework for researching different aspects of Information Technology including outputs of the research (research outputs) and activities to carry out this research (research activities). They identified research outputs as follows:
Also research activities including:
Although Information Systems as a discipline has been evolving for over 30 years now,[58] the core focus or identity of IS research is still subject to debate among scholars.[59][60][61] There are two main views around this debate: a narrow view focusing on the IT artifact as the core subject matter of IS research, and a broad view that focuses on the interplay between social and technical aspects of IT that is embedded into a dynamic evolving context.[62] A third view[63] calls on IS scholars to pay balanced attention to both the IT artifact and its context.
Since the study of information systems is an applied field, industry practitioners expect information systems research to generate findings that are immediately applicable in practice. This is not always the case however, as information systems researchers often explore behavioral issues in much more depth than practitioners would expect them to do. This may render information systems research results difficult to understand, and has led to criticism.[64]
In the last ten years, the business trend is represented by the considerable increasing of Information Systems Function (ISF) role, especially with regard the enterprise strategies and operations supporting. It became a key-factor to increase productivity and to support new value creation.[65] To study an information system itself, rather than its effects, information systems models are used, such as EATPUT.
The international body of Information Systems researchers, the Association for Information Systems (AIS), and its Senior Scholars Forum Subcommittee on Journals (23 April 2007), proposed a 'basket' of journals that the AIS deems as 'excellent', and nominated: Management Information Systems Quarterly (MISQ), Information Systems Research (ISR), Journal of the Association for Information Systems (JAIS), Journal of Management Information Systems (JMIS), European Journal of Information Systems (EJIS), and Information Systems Journal (ISJ).[66]
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A number of annual information systems conferences are run in various parts of the world, the majority of which are peer reviewed. The AIS directly runs the International Conference on Information Systems (ICIS) and the Americas Conference on Information Systems (AMCIS), while AIS affiliated conferences[67] include the Pacific Asia Conference on Information Systems (PACIS), European Conference on Information Systems (ECIS), the Mediterranean Conference on Information Systems (MCIS), the International Conference on Information Resources Management (Conf-IRM) and the Wuhan International Conference on E-Business (WHICEB). AIS chapter conferences[68] include Australasian Conference on Information Systems (ACIS), Information Systems Research Conference in Scandinavia (IRIS), Information Systems International Conference (ISICO), Conference of the Italian Chapter of AIS (itAIS), Annual Mid-Western AIS Conference (MWAIS) and Annual Conference of the Southern AIS (SAIS). EDSIG,[69] which is the special interest group on education of the AITP,[70] organizes the Conference on Information Systems and Computing Education[71] and the Conference on Information Systems Applied Research[72] which are both held annually in November.
The impact on economic models[edit]
See also[edit]
References[edit]
Donella Meadows DeathFurther reading[edit]
Donella Meadows Thinking In Systems Pdf To Excel PdfExternal links[edit]
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