A digital twin is a digital model of an intended or actual real-world physical product, system, or process (a physical twin ) that serves as the effectively indistinguishable digital counterpart of it for practical purposes, such as simulation , integration , testing , monitoring , and maintenance .
116-414: A digital twin is set of adaptive models that emulate the behaviour of a physical system in a virtual system getting real time data to update itself along its life cycle. The digital twin replicates the physical system to predict failures and opportunities for changing, to prescribe real time actions for optimizing and/or mitigating unexpected events observing and evaluating the operating profile system. Though
232-423: A bit only when the clock changes. The usual way to implement a synchronous sequential state machine is to divide it into a piece of combinational logic and a set of flip flops called a state register . The state register represents the state as a binary number. The combinational logic produces the binary representation for the next state. On each clock cycle, the state register captures the feedback generated from
348-598: A computer , the model being designed to represent the behaviour of, or the outcome of, a real-world or physical system. The reliability of some mathematical models can be determined by comparing their results to the real-world outcomes they aim to predict. Computer simulations have become a useful tool for the mathematical modeling of many natural systems in physics ( computational physics ), astrophysics , climatology , chemistry , biology and manufacturing , as well as human systems in economics , psychology , social science , health care and engineering . Simulation of
464-467: A printed circuit board which is a board which holds electrical components, and connects them together with copper traces. Engineers use many methods to minimize logic redundancy in order to reduce the circuit complexity. Reduced complexity reduces component count and potential errors and therefore typically reduces cost. Logic redundancy can be removed by several well-known techniques, such as binary decision diagrams , Boolean algebra , Karnaugh maps ,
580-410: A truth table . An equivalent high-level circuit uses logic gates , each represented by a different shape (standardized by IEEE / ANSI 91–1984). A low-level representation uses an equivalent circuit of electronic switches (usually transistors ). Most digital systems divide into combinational and sequential systems . The output of a combinational system depends only on the present inputs. However,
696-430: A bundle of wires called a bus that carries that number to other calculations. A calculation is simply a piece of combinational logic. Each calculation also has an output bus, and these may be connected to the inputs of several registers. Sometimes a register will have a multiplexer on its input so that it can store a number from any one of several buses. Asynchronous register-transfer systems (such as computers) have
812-438: A clock distribution network is not needed. An unexpected advantage is that asynchronous computers do not produce spectrally-pure radio noise. They are used in some radio-sensitive mobile-phone base-station controllers. They may be more secure in cryptographic applications because their electrical and radio emissions can be more difficult to decode. Computer architecture is a specialized engineering activity that tries to arrange
928-466: A collection of much simpler logic machines. Almost all computers are synchronous. However, asynchronous computers have also been built. One example is the ASPIDA DLX core. Another was offered by ARM Holdings . They do not, however, have any speed advantages because modern computer designs already run at the speed of their slowest component, usually memory. They do use somewhat less power because
1044-530: A desert-battle simulation of one force invading another involved the modeling of 66,239 tanks, trucks and other vehicles on simulated terrain around Kuwait , using multiple supercomputers in the DoD High Performance Computer Modernization Program. Other examples include a 1-billion-atom model of material deformation; a 2.64-million-atom model of the complex protein-producing organelle of all living organisms,
1160-400: A different answer for each execution. Although this might seem obvious, this is a special point of attention in stochastic simulations , where random numbers should actually be semi-random numbers. An exception to reproducibility are human-in-the-loop simulations such as flight simulations and computer games . Here a human is part of the simulation and thus influences the outcome in a way that
1276-437: A different clock, the digital system can be subject to metastability where a change to the input violates the setup time for a digital input latch. Since digital circuits are made from analog components, digital circuits calculate more slowly than low-precision analog circuits that use a similar amount of space and power. However, the digital circuit will calculate more repeatably, because of its high noise immunity. Much of
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#17327757938821392-529: A digital footprint of all of their products, from design to development and throughout the entire product life cycle. Broadly speaking, industries with manufacturing business are highly disrupted by digital twins. In the manufacturing process, the digital twin is like a virtual replica of the near-time occurrences in the factory. Thousands of sensors are being placed throughout the physical manufacturing process, all collecting data from different dimensions, such as environmental conditions, behavioural characteristics of
1508-406: A digital system, as long as the total noise is below a certain level, the information can be recovered perfectly. Even when more significant noise is present, the use of redundancy permits the recovery of the original data provided too many errors do not occur. In some cases, digital circuits use more energy than analog circuits to accomplish the same tasks, thus producing more heat which increases
1624-404: A general solution. In the 1980s, some researchers discovered that almost all synchronous register-transfer machines could be converted to asynchronous designs by using first-in-first-out synchronization logic. In this scheme, the digital machine is characterized as a set of data flows. In each step of the flow, a synchronization circuit determines when the outputs of that step are valid and instructs
1740-429: A logic gate can, in turn, control or feed into more logic gates. Another form of digital circuit is constructed from lookup tables, (many sold as " programmable logic devices ", though other kinds of PLDs exist). Lookup tables can perform the same functions as machines based on logic gates, but can be easily reprogrammed without changing the wiring. This means that a designer can often repair design errors without changing
1856-779: A logical extension - at an individual asset level and at a national level. In the United Kingdom in November 2018, for example, the Centre for Digital Built Britain published The Gemini Principles , outlining principles to guide development of a "national digital twin". One of the earliest examples of a working 'digital twin' was achieved in 1996 during construction of the Heathrow Express facilities at Heathrow Airport 's Terminal 1 . Consultant Mott MacDonald and BIM pioneer Jonathan Ingram connected movement sensors in
1972-470: A map that uses numeric coordinates and numeric timestamps of events. Similarly, CGI computer simulations of CAT scans can simulate how a tumor might shrink or change during an extended period of medical treatment, presenting the passage of time as a spinning view of the visible human head, as the tumor changes. Other applications of CGI computer simulations are being developed to graphically display large amounts of data, in motion, as changes occur during
2088-418: A mutually beneficial manner. The digital twin is disrupting the entire product lifecycle management (PLM), from design, to manufacturing, to service and operations. Nowadays, PLM is very time-consuming in terms of efficiency, manufacturing, intelligence, service phases and sustainability in product design. A digital twin can merge the product physical and virtual space. The digital twin enables companies to have
2204-998: A problem before actually breaking down. Furthermore, as storage and computing costs are becoming less expensive, the ways in which digital twins are used are expanding. Implementation challenges such as data integration , organizational or compliance challenges can hinder the implementation of digital twins and its benefits. Digital twins are transforming construction by creating dynamic digital replicas of physical assets. They support health monitoring, ergonomic risk assessment, and predictive maintenance of structures like bridges and historical buildings. Applications also optimize building energy and carbon performance. Case studies, such as Weihai Port, highlight their practical success. Digital twins rely on robust system architectures and tailored, requirements-driven designs. Advanced models like LSTM enable predictive capabilities, though challenges in integration and scaling remain. Geographic digital twins have been popularised in urban planning practice, given
2320-423: A relatively compact space. In 1955, Carl Frosch and Lincoln Derick discovered silicon dioxide surface passivation effects. In 1957 Frosch and Derick, using masking and predeposition, were able to manufacture silicon dioxide field effect transistors; the first planar transistors, in which drain and source were adjacent at the same surface. At Bell Labs, the importance of Frosch and Derick technique and transistors
2436-596: A sequential system has some of its outputs fed back as inputs, so its output may depend on past inputs in addition to present inputs, to produce a sequence of operations. Simplified representations of their behavior called state machines facilitate design and test. Sequential systems divide into two further subcategories. "Synchronous" sequential systems change state all at once when a clock signal changes state. "Asynchronous" sequential systems propagate changes whenever inputs change. Synchronous sequential systems are made using flip flops that store inputted voltages as
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#17327757938822552-497: A simulation run. Generic examples of types of computer simulations in science, which are derived from an underlying mathematical description: Specific examples of computer simulations include: Notable, and sometimes controversial, computer simulations used in science include: Donella Meadows ' World3 used in the Limits to Growth , James Lovelock's Daisyworld and Thomas Ray's Tierra . In social sciences, computer simulation
2668-660: A simulation". Computer simulation developed hand-in-hand with the rapid growth of the computer, following its first large-scale deployment during the Manhattan Project in World War II to model the process of nuclear detonation . It was a simulation of 12 hard spheres using a Monte Carlo algorithm . Computer simulation is often used as an adjunct to, or substitute for, modeling systems for which simple closed form analytic solutions are not possible. There are many types of computer simulations; their common feature
2784-434: A single bit error may cause a much larger disruption. Because of the cliff effect , it can be difficult for users to tell if a particular system is right on the edge of failure, or if it can tolerate much more noise before failing. Digital fragility can be reduced by designing a digital system for robustness . For example, a parity bit or other error management method can be inserted into the signal path. These schemes help
2900-418: A single factory, but to all the factories across the globe. (Grieves, 2014, p. 5) As stated above, a digital twin enables a physical product to be reprogrammable in a certain way. Furthermore, the digital twin is also reprogrammable in an automatic manner, through the sensors on the physical product, artificial intelligence technologies, and predictive analytics . A consequence of this reprogrammable nature
3016-420: A state in which the system is in equilibrium. Such models are often used in simulating physical systems, as a simpler modeling case before dynamic simulation is attempted. Formerly, the output data from a computer simulation was sometimes presented in a table or a matrix showing how data were affected by numerous changes in the simulation parameters . The use of the matrix format was related to traditional use of
3132-408: A supply chain can be increased by enabling members of this supply chain to check the digital twin of a product or asset. These partners can then check the status of this product by simply checking the digital twin. Servitization is the process of organizations that are adding value to their core corporate offerings through services. In the case of the example of engines, the manufacturing of the engine
3248-631: A system is represented as the running of the system's model. It can be used to explore and gain new insights into new technology and to estimate the performance of systems too complex for analytical solutions . Computer simulations are realized by running computer programs that can be either small, running almost instantly on small devices, or large-scale programs that run for hours or days on network-based groups of computers. The scale of events being simulated by computer simulations has far exceeded anything possible (or perhaps even imaginable) using traditional paper-and-pencil mathematical modeling. In 1997,
3364-553: A version of the 16-row truth table as proposition 5.101 of Tractatus Logico-Philosophicus (1921). Walther Bothe , inventor of the coincidence circuit , shared the 1954 Nobel Prize in physics, for creating the first modern electronic AND gate in 1924. Mechanical analog computers started appearing in the first century and were later used in the medieval era for astronomical calculations. In World War II , mechanical analog computers were used for specialized military applications such as calculating torpedo aiming. During this time
3480-599: A virtual model of the affected area. Healthcare is recognized as an industry being disrupted by the digital twin technology. The concept of digital twin in the healthcare industry was originally proposed and first used in product or equipment prognostics. With a digital twin, lives can be improved in terms of medical health, sports and education by taking a more data-driven approach to healthcare. The availability of technologies makes it possible to build personalized models for patients, continuously adjustable based on tracked health and lifestyle parameters. This can ultimately lead to
3596-503: A virtual patient, with detailed description of the healthy state of an individual patient and not only on previous records. Furthermore, the digital twin enables individual's records to be compared to the population in order to easier find patterns with great detail. The biggest benefit of the digital twin on the healthcare industry is the fact that healthcare can be tailored to anticipate on the responses of individual patients. Digital twins will not only lead to better resolutions when defining
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3712-418: A virtual representation of the product (in the form of a digital twin), thus decoupling the information from its physical form. Therefore, the homogenization of data and the decoupling of the information from its physical artifact, have allowed digital twins to come into existence. However, digital twins also enable increasingly more information on physical products to be stored digitally and become decoupled from
3828-419: A wide variety of practical contexts, such as: The reliability and the trust people put in computer simulations depends on the validity of the simulation model , therefore verification and validation are of crucial importance in the development of computer simulations. Another important aspect of computer simulations is that of reproducibility of the results, meaning that a simulation model should not provide
3944-439: Is an integral component of the five angles of analysis fostered by the data percolation methodology, which also includes qualitative and quantitative methods, reviews of the literature (including scholarly), and interviews with experts, and which forms an extension of data triangulation. Of course, similar to any other scientific method, replication is an important part of computational modeling Computer simulations are used in
4060-446: Is based on this connection; without it, digital twin technology would not exist. As described in the previous section, this connectivity is created by sensors on the physical product which obtain data and integrate and communicate this data through various integration technologies. Digital twin technology enables increased connectivity between organizations, products, and customers. For example, connectivity between partners and customers in
4176-400: Is considered to be arguably the most important master's thesis ever written, winning the 1939 Alfred Noble Prize . The Z3 was an electromechanical computer designed by Konrad Zuse . Finished in 1941, it was the world's first working programmable , fully automatic digital computer. Its operation was facilitated by the invention of the vacuum tube in 1904 by John Ambrose Fleming . At
4292-414: Is hard, if not impossible, to reproduce exactly. Vehicle manufacturers make use of computer simulation to test safety features in new designs. By building a copy of the car in a physics simulation environment, they can save the hundreds of thousands of dollars that would otherwise be required to build and test a unique prototype. Engineers can step through the simulation milliseconds at a time to determine
4408-579: Is its connectivity. The recent development of the Internet of Things (IoT) brings forward numerous new technologies. The development of IoT also brings forward the development of digital twin technology. This technology shows many characteristics that have similarities with the character of the IoT, namely its connective nature. First and foremost, the technology enables connectivity between the physical component and its digital counterpart. The basis of digital twins
4524-486: Is known to only one significant figure, then the result of the simulation might not be more precise than one significant figure, although it might (misleadingly) be presented as having four significant figures. Digital electronics Digital electronics is a field of electronics involving the study of digital signals and the engineering of devices that use or produce them. This is in contrast to analog electronics which work primarily with analog signals . Despite
4640-409: Is meant to be an up-to-date and accurate copy of the physical object's properties and states, including shape, position, gesture, status and motion. A digital twin also can be used for monitoring , diagnostics and prognostics to optimize asset performance and utilization. In this field, sensory data can be combined with historical data, human expertise and fleet and simulation learning to improve
4756-450: Is much harder is knowing what the accuracy (compared to measurement resolution and precision ) of the values are. Often they are expressed as "error bars", a minimum and maximum deviation from the value range within which the true value (is expected to) lie. Because digital computer mathematics is not perfect, rounding and truncation errors multiply this error, so it is useful to perform an "error analysis" to confirm that values output by
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4872-472: Is needed to accurately portray a given analog signal. If a single piece of digital data is lost or misinterpreted, in some systems only a small error may result, while in other systems the meaning of large blocks of related data can completely change. For example, a single-bit error in audio data stored directly as linear pulse-code modulation causes, at worst, a single audible click. But when using audio compression to save storage space and transmission time,
4988-493: Is that signals represented digitally can be transmitted without degradation caused by noise . For example, a continuous audio signal transmitted as a sequence of 1s and 0s, can be reconstructed without error, provided the noise picked up in transmission is not enough to prevent identification of the 1s and 0s. In a digital system, a more precise representation of a signal can be obtained by using more binary digits to represent it. While this requires more digital circuits to process
5104-503: Is the attempt to generate a sample of representative scenarios for a model in which a complete enumeration of all possible states of the model would be prohibitive or impossible. The external data requirements of simulations and models vary widely. For some, the input might be just a few numbers (for example, simulation of a waveform of AC electricity on a wire), while others might require terabytes of information (such as weather and climate models). Input sources also vary widely: Lastly,
5220-421: Is the core offering of this organization, they then add value by providing a service of checking the engine and offering maintenance. Digital twins can be further characterized as a digital technology that is both the consequence and an enabler of the homogenization of data. Due to the fact that any type of information or content can now be stored and transmitted in the same digital form, it can be used to create
5336-420: Is the emergence of functionalities. If we take the example of an engine again, digital twins can be used to collect data about the performance of the engine and if needed adjust the engine, creating a newer version of the product. Also, servitization can be seen as a consequence of the reprogrammable nature as well. Manufacturers can be responsible for observing the digital twin, making adjustments, or reprogramming
5452-465: Is to construct a table of the minimum and maximum time that each such state can exist and then adjust the circuit to minimize the number of such states. The designer must force the circuit to periodically wait for all of its parts to enter a compatible state (this is called "self-resynchronization"). Without careful design, it is easy to accidentally produce asynchronous logic that is unstable—that is—real electronics will have unpredictable results because of
5568-486: Is very important to perform a sensitivity analysis to ensure that the accuracy of the results is properly understood. For example, the probabilistic risk analysis of factors determining the success of an oilfield exploration program involves combining samples from a variety of statistical distributions using the Monte Carlo method . If, for instance, one of the key parameters (e.g., the net ratio of oil-bearing strata)
5684-500: The Quine–McCluskey algorithm or binary decision diagrams . There are promising experiments with genetic algorithms and annealing optimizations . To automate costly engineering processes, some EDA can take state tables that describe state machines and automatically produce a truth table or a function table for the combinational logic of a state machine. The state table is a piece of text that lists each state, together with
5800-509: The Quine–McCluskey algorithm , and the heuristic computer method . These operations are typically performed within a computer-aided design system. Embedded systems with microcontrollers and programmable logic controllers are often used to implement digital logic for complex systems that do not require optimal performance. These systems are usually programmed by software engineers or by electricians, using ladder logic . A digital circuit's input-output relationship can be represented as
5916-544: The business processes that contribute toward its production . The first digital twin, although not labeled as such, came about at NASA during the 1960s as a means of modelling the Apollo missions . NASA used simulators to evaluate the failure of Apollo 13's oxygen tanks. The broader idea that became the digital twin concept was anticipated by David Gelernter 's 1991 book Mirror Worlds . The digital twin concept, which has been known by different names (e.g., virtual twin) ,
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#17327757938826032-550: The ribosome , in 2005; a complete simulation of the life cycle of Mycoplasma genitalium in 2012; and the Blue Brain project at EPFL (Switzerland), begun in May 2005 to create the first computer simulation of the entire human brain, right down to the molecular level. Because of the computational cost of simulation, computer experiments are used to perform inference such as uncertainty quantification . A model consists of
6148-526: The silicon integrated circuit. The basis for Noyce's silicon IC was Hoerni's planar process . The MOSFET's advantages include high scalability , affordability, low power consumption, and high transistor density . Its rapid on–off electronic switching speed also makes it ideal for generating pulse trains , the basis for electronic digital signals , in contrast to BJTs which, more slowly, generate analog signals resembling sine waves . Along with MOS large-scale integration (LSI), these factors make
6264-440: The 1990s and was enabled by the wide adoption of MOSFET-based RF power amplifiers ( power MOSFET and LDMOS ) and RF circuits ( RF CMOS ). Wireless networks allowed for public digital transmission without the need for cables, leading to digital television , satellite and digital radio , GPS , wireless Internet and mobile phones through the 1990s–2000s. An advantage of digital circuits when compared to analog circuits
6380-484: The MOSFET an important switching device for digital circuits . The MOSFET revolutionized the electronics industry , and is the most common semiconductor device . In the early days of integrated circuits , each chip was limited to only a few transistors, and the low degree of integration meant the design process was relatively simple. Manufacturing yields were also quite low by today's standards. The wide adoption of
6496-703: The MOSFET transistor by the early 1970s led to the first large-scale integration (LSI) chips with more than 10,000 transistors on a single chip. Following the wide adoption of CMOS , a type of MOSFET logic, by the 1980s, millions and then billions of MOSFETs could be placed on one chip as the technology progressed, and good designs required thorough planning, giving rise to new design methods . The transistor count of devices and total production rose to unprecedented heights. The total amount of transistors produced until 2018 has been estimated to be 1.3 × 10 (13 sextillion ). The wireless revolution (the introduction and proliferation of wireless networks ) began in
6612-617: The actual system." The evolving US DoD Digital Engineering Strategy initiative, first formulated in 2018, defines a digital twin as "an integrated multiphysics, multiscale, probabilistic simulation of an as-built system, enabled by a Digital Thread, that uses the best available models, sensor information, and input data to mirror and predict activities/performance over the life of its corresponding physical twin." Digital twins are commonly divided into subtypes that sometimes include: digital twin prototype (DTP), digital twin instance (DTI), and digital twin aggregate (DTA). The DTP consists of
6728-472: The analog nature of the components does not dominate the desired digital behavior. Digital systems must manage noise and timing margins, parasitic inductances and capacitances. Bad designs have intermittent problems such as glitches , vanishingly fast pulses that may trigger some logic but not others, runt pulses that do not reach valid threshold voltages . Additionally, where clocked digital systems interface to analog systems or systems that are driven from
6844-420: The arrangement of wires. Therefore, in small volume products, programmable logic devices are often the preferred solution. They are usually designed by engineers using electronic design automation software. Integrated circuits consist of multiple transistors on one silicon chip, and are the least expensive way to make large number of interconnected logic gates. Integrated circuits are usually interconnected on
6960-402: The automotive application, in particular when the related algorithms are based on artificial intelligence approaches that require extensive training data and validation data sets. The physical manufacturing objects are virtualized and represented as digital twin models (avatars) seamlessly and closely integrated in both the physical and cyber spaces. Physical objects and twin models interact in
7076-420: The automotive industry is where automotive engineers use digital twin technology in combination with the firm's analytical tool in order to analyze how a specific car is driven. In doing so, they can suggest incorporating new features in the car that can reduce car accidents on the road, which was previously not possible in such a short time frame. Digital twins can be built for not just individual vehicles but also
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#17327757938827192-544: The binary system, the principles of arithmetic and logic could be joined. Digital logic as we know it was the brain-child of George Boole in the mid 19th century. In an 1886 letter, Charles Sanders Peirce described how logical operations could be carried out by electrical switching circuits. Eventually, vacuum tubes replaced relays for logic operations. Lee De Forest 's modification of the Fleming valve in 1907 could be used as an AND gate . Ludwig Wittgenstein introduced
7308-678: The buildup of queues in the simulation of humans evacuating a building. Furthermore, simulation results are often aggregated into static images using various ways of scientific visualization . In debugging, simulating a program execution under test (rather than executing natively) can detect far more errors than the hardware itself can detect and, at the same time, log useful debugging information such as instruction trace, memory alterations and instruction counts. This technique can also detect buffer overflow and similar "hard to detect" errors as well as produce performance information and tuning data. Although sometimes ignored in computer simulations, it
7424-552: The built environment integrating data feeds from embedded sensors in cities and API services to form digital twins. For example, AR can be used to create augmented reality maps, buildings, and data feeds projected onto tabletops for collaborative viewing by built environment professionals. In the built environment, partly through the adoption of building information modeling (BIM) processes, planning, design, construction, and operation and maintenance activities are increasingly being digitised, and digital twins of built assets are seen as
7540-412: The cofferdam and boreholes to the digital object-model to display movements in the model. A digital grouting object was made to monitor the effects of pumping grout into the earth to stabilise ground movements. Digital twins have also been proposed as a method to reduce the need for visual inspections of buildings and infrastructure after earthquakes by using unmanned vehicles to gather data to be added to
7656-459: The complexity of the circuits such as the inclusion of heat sinks. In portable or battery-powered systems this can limit the use of digital systems. For example, battery-powered cellular phones often use a low-power analog front-end to amplify and tune the radio signals from the base station. However, a base station has grid power and can use power-hungry, but very flexible software radios . Such base stations can easily be reprogrammed to process
7772-401: The computer. The sequencer then counts, and the count addresses the memory or combinational logic machine that contains the microprogram. The bits from the microprogram control the arithmetic logic unit , memory and other parts of the computer, including the microsequencer itself. In this way, the complex task of designing the controls of a computer is reduced to the simpler task of programming
7888-431: The concept originated earlier (as a natural aspect of computer simulation generally), the first practical definition of a digital twin originated from NASA in an attempt to improve the physical-model simulation of spacecraft in 2010. Digital twins are the result of continual improvement in modeling and engineering. In the 2010s and 2020s, manufacturing industries began moving beyond digital product definition to extending
8004-480: The conditions controlling the transitions between them and their associated output signals. Often, real logic systems are designed as a series of sub-projects, which are combined using a tool flow . The tool flow is usually controlled with the help of a scripting language , a simplified computer language that can invoke the software design tools in the right order. Tool flows for large logic systems such as microprocessors can be thousands of commands long, and combine
8120-512: The cumulative delays caused by small variations in the values of the electronic components. Many digital systems are data flow machines . These are usually designed using synchronous register transfer logic and written with hardware description languages such as VHDL or Verilog . In register transfer logic, binary numbers are stored in groups of flip flops called registers . A sequential state machine controls when each register accepts new data from its input. The outputs of each register are
8236-416: The designs, analyses, and processes that realize a physical product. The DTP exists before there is a physical product. The DTI is the digital twin of each individual instance of the product once it is manufactured. The DTI is linked with its physical counterpart for the remainder of the physical counterpart's life. The DTA is the aggregation of DTIs whose data and information can be used for interrogation about
8352-476: The diffusion processes, and H. K. Gummel and R. Lindner who characterized the device. While working at Texas Instruments in July 1958, Jack Kilby recorded his initial ideas concerning the integrated circuit (IC), then successfully demonstrated the first working integrated circuit on 12 September 1958. Kilby's chip was made of germanium . The following year, Robert Noyce at Fairchild Semiconductor invented
8468-434: The digital twin concept to the entire manufacturing process. Doing so allows the benefits of virtualization to be extended to domains such as inventory management including lean manufacturing , machinery crash avoidance, tooling design, troubleshooting , and preventive maintenance . Digital twinning therefore allows extended reality and spatial computing to be applied not just to the product itself but also to all of
8584-407: The digital twin when needed and they can offer this as an extra service. Another characteristic that can be observed, is the fact that digital twin technologies leave digital traces. These traces can be used by engineers for example, when a machine malfunctions to go back and check the traces of the digital twin, to diagnose where the problem occurred. These diagnoses can in the future also be used by
8700-527: The effort of designing large logic machines has been automated through the application of electronic design automation (EDA). Simple truth table-style descriptions of logic are often optimized with EDA that automatically produce reduced systems of logic gates or smaller lookup tables that still produce the desired outputs. The most common example of this kind of software is the Espresso heuristic logic minimizer . Optimizing large logic systems may be done using
8816-415: The equations used to capture the behavior of a system. By contrast, computer simulation is the actual running of the program that perform algorithms which solve those equations, often in an approximate manner. Simulation, therefore, is the process of running a model. Thus one would not "build a simulation"; instead, one would "build a model (or a simulator)", and then either "run the model" or equivalently "run
8932-428: The exact stresses being put upon each section of the prototype. Computer graphics can be used to display the results of a computer simulation. Animations can be used to experience a simulation in real-time, e.g., in training simulations . In some cases animations may also be useful in faster than real-time or even slower than real-time modes. For example, faster than real-time animations can be useful in visualizing
9048-408: The factory by updating the product's software. This way, the product's design errors can be corrected even after the product is in a customer's hands. Information storage can be easier in digital systems than in analog ones. The noise immunity of digital systems permits data to be stored and retrieved without degradation. In an analog system, noise from aging and wear degrade the information stored. In
9164-477: The first electronic digital computers were developed, with the term digital being proposed by George Stibitz in 1942 . Originally they were the size of a large room, consuming as much power as several hundred modern PCs . Claude Shannon , demonstrating that electrical applications of Boolean algebra could construct any logical numerical relationship, ultimately laid the foundations of digital computing and digital circuits in his master's thesis of 1937, which
9280-522: The gap between the rich and poor. Furthermore, the digital twin will identify patterns in a population which may lead to discrimination. The automobile industry has been improved by digital twin technology. Digital twins in the automobile industry are implemented by using existing data in order to facilitate processes and reduce marginal costs. Currently, automobile designers expand the existing physical materiality by incorporating software-based digital abilities. A specific example of digital twin technology in
9396-460: The health of an individual patient but also change the expected image of a healthy patient. Previously, 'healthy' was seen as the absence of disease indications. Now, 'healthy' patients can be compared to the rest of the population in order to really define healthy. However, the emergence of the digital twin in healthcare also brings some downsides. The digital twin may lead to inequality, as the technology might not be accessible for everyone by widening
9512-405: The homogenization and decoupling of information is that the user experience converges. As information from physical objects is digitized, a single artifact can have multiple new affordances. Digital twin technology allows detailed information about a physical object to be shared with a larger number of agents, unconstrained by physical location or time. In his white paper on digital twin technology in
9628-488: The increasing appetite for digital technology in the Smart Cities movement. These digital twins are often proposed in the form of interactive platforms to capture and display real-time 3D and 4D spatial data in order to model urban environments (cities) and the data feeds within them. Visualization technologies such as augmented reality (AR) systems are being used as both collaborative tools for design and planning in
9744-702: The leadership of Tom Kilburn designed and built a machine using the newly developed transistors instead of vacuum tubes. Their " transistorised computer ", and the first in the world, was operational by 1953 , and a second version was completed there in April 1955. From 1955 and onwards, transistors replaced vacuum tubes in computer designs, giving rise to the "second generation" of computers. Compared to vacuum tubes, transistors were smaller, more reliable, had indefinite lifespans, and required less power than vacuum tubes - thereby giving off less heat, and allowing much denser concentrations of circuits, up to tens of thousands in
9860-399: The machine and work that is being performed. All this data is continuously communicating and collected by the digital twin. Advanced ways of product and asset maintenance and management come within reach as there is a digital twin of the real 'thing' with real-time capabilities. Digital twins offer a great amount of business potential by predicting the future instead of analyzing the past of
9976-405: The machines that are used and notice possible areas of improvement in the machines. When these machines are made modular, by using digital twin technology, manufacturers can see which components make the machine perform poorly and replace these with better fitting components to improve the manufacturing process. An example of digital twins is the use of 3D modeling to create digital companions for
10092-437: The manufacturer of these machines, to improve their designs so that these same malfunctions will occur less often in the future. In the sense of the manufacturing industry, modularity can be described as the design and customization of products and production modules. By adding modularity to the manufacturing models, manufacturers gain the ability to tweak models and machines. Digital twin technology enables manufacturers to track
10208-427: The manufacturing industry, Michael Grieves noted the following about the consequences of homogenization enabled by digital twins: In the past, factory managers had their office overlooking the factory so that they could get a feel for what was happening on the factory floor. With the digital twin, not only the factory manager, but everyone associated with factory production could have that same virtual window to not only
10324-480: The manufacturing process. The representation of reality created by digital twins allows manufacturers to evolve towards ex-ante business practices. The future of manufacturing drives on the following four aspects: modularity, autonomy, connectivity and digital twin. As there is an increasing digitalization in the stages of a manufacturing process, opportunities are opening up to achieve a higher productivity. This starts with modularity and leading to higher effectiveness in
10440-452: The matrix concept in mathematical models . However, psychologists and others noted that humans could quickly perceive trends by looking at graphs or even moving-images or motion-pictures generated from the data, as displayed by computer-generated-imagery (CGI) animation. Although observers could not necessarily read out numbers or quote math formulas, from observing a moving weather chart they might be able to predict events (and "see that rain
10556-484: The maximum speed of its logic gates. Nevertheless, most systems need to accept external unsynchronized signals into their synchronous logic circuits. This interface is inherently asynchronous and must be analyzed as such. Examples of widely used asynchronous circuits include synchronizer flip-flops, switch debouncers and arbiters . Asynchronous logic components can be hard to design because all possible states, in all possible timings must be considered. The usual method
10672-471: The mechanism of thermally grown oxides, fabricated a high quality Si/ SiO 2 stack and published their results in 1960. Following this research at Bell Labs, Mohamed Atalla and Dawon Kahng proposed a silicon MOS transistor in 1959 and successfully demonstrated a working MOS device with their Bell Labs team in 1960. The team included E. E. LaBate and E. I. Povilonis who fabricated the device; M. O. Thurston, L. A. D’Asaro, and J. R. Ligenza who developed
10788-436: The name, digital electronics designs includes important analog design considerations. Digital electronic circuits are usually made from large assemblies of logic gates , often packaged in integrated circuits . Complex devices may have simple electronic representations of Boolean logic functions . The binary number system was refined by Gottfried Wilhelm Leibniz (published in 1705) and he also established that by using
10904-400: The next stage when to use these outputs. The most general-purpose register-transfer logic machine is a computer . This is basically an automatic binary abacus . The control unit of a computer is usually designed as a microprogram run by a microsequencer . A microprogram is much like a player-piano roll. Each table entry of the microprogram commands the state of every bit that controls
11020-417: The outcome of prognostics. Therefore, complex prognostics and intelligent maintenance system platforms can use digital twins in finding the root cause of issues and improve productivity . Digital twins of autonomous vehicles and their sensor suites embedded in a traffic and environment simulation have also been proposed as a means to overcome the significant development, testing and validation challenges for
11136-435: The outputs of simulated logic against expected inputs. The test tools take computer files with sets of inputs and outputs and highlight discrepancies between the simulated behavior and the expected behavior. Once the input data is believed to be correct, the design itself must still be verified for correctness. Some tool flows verify designs by first producing a design, then scanning the design to produce compatible input data for
11252-405: The physical and virtual objects and environments. The communication connection is referred to as the digital thread. The International Council of Systems Engineers (INCOSE) maintains in its Systems Engineering Book of Knowledge (SEBoK) that: "A digital twin is a related yet distinct concept to digital engineering. The digital twin is a high-fidelity model of the system which can be used to emulate
11368-409: The physical objects. It can be used to view the status of the actual physical object, which provides a way to project physical objects into the digital world. For example, when sensors collect data from a connected device, the sensor data can be used to update a "digital twin" copy of the device's state in real time. The term "device shadow" is also used for the concept of a digital twin. The digital twin
11484-419: The physical product, prognostics, and learning. The specific information contained in the digital twins is driven by use cases. The digital twin is a logical construct, meaning that the actual data and information may be contained in other applications. Digital twin technologies have certain characteristics that distinguish them from other technologies: One of the main characteristics of digital twin technology
11600-457: The previous state of the combinational logic and feeds it back as an unchanging input to the combinational part of the state machine. The clock rate is limited by the most time-consuming logic calculation in the combinational logic. Most digital logic is synchronous because it is easier to create and verify a synchronous design. However, asynchronous logic has the advantage of its speed not being constrained by an arbitrary clock; instead, it runs at
11716-596: The product itself. As data is increasingly digitized, it can be transmitted, stored and computed in fast and low-cost ways. According to Moore's law , computing power will continue to increase exponentially over the coming years, while the cost of computing decreases significantly. This would, therefore, lead to lower marginal costs of developing digital twins and make it comparatively much cheaper to test, predict, and solve problems on virtual representations rather than testing on physical models and waiting for physical products to break before intervening. Another consequence of
11832-450: The production system. Furthermore, autonomy enables the production system to respond to unexpected events in an efficient and intelligent way. Lastly, connectivity like the internet of things , makes the closing of the digitalization loop possible, by then allowing the following cycle of product design and promotion to be optimized for higher performance. This may lead to increase in customer satisfaction and loyalty when products can determine
11948-505: The registers, calculation logic, buses and other parts of the computer in the best way possible for a specific purpose. Computer architects have put a lot of work into reducing the cost and increasing the speed of computers in addition to boosting their immunity to programming errors. An increasingly common goal of computer architects is to reduce the power used in battery-powered computer systems, such as smartphones . Digital circuits are made from analog components. The design must assure that
12064-466: The same time that digital calculation replaced analog, purely electronic circuit elements soon replaced their mechanical and electromechanical equivalents. John Bardeen and Walter Brattain invented the point-contact transistor at Bell Labs in 1947, followed by William Shockley inventing the bipolar junction transistor at Bell Labs in 1948. At the University of Manchester , a team under
12180-418: The signals used in new cellular standards. Many useful digital systems must translate from continuous analog signals to discrete digital signals. This causes quantization errors . Quantization error can be reduced if the system stores enough digital data to represent the signal to the desired degree of fidelity . The Nyquist–Shannon sampling theorem provides an important guideline as to how much digital data
12296-429: The signals, each digit is handled by the same kind of hardware, resulting in an easily scalable system. In an analog system, additional resolution requires fundamental improvements in the linearity and noise characteristics of each step of the signal chain . With computer-controlled digital systems, new functions can be added through software revision and no hardware changes are needed. Often this can be done outside of
12412-436: The simulation will still be usefully accurate. Models used for computer simulations can be classified according to several independent pairs of attributes, including: Another way of categorizing models is to look at the underlying data structures. For time-stepped simulations, there are two main classes: For steady-state simulations, equations define the relationships between elements of the modeled system and attempt to find
12528-411: The structure of the logic and systematically generating tests targeting particular potential faults. This way the fault coverage can closely approach 100%, provided the design is properly made testable (see next section). Once a design exists, and is verified and testable, it often needs to be processed to be manufacturable as well. Modern integrated circuits have features smaller than the wavelength of
12644-517: The system detect errors, and then either correct the errors , or request retransmission of the data. A digital circuit is typically constructed from small electronic circuits called logic gates that can be used to create combinational logic . Each logic gate is designed to perform a function of Boolean logic when acting on logic signals. A logic gate is generally created from one or more electrically controlled switches, usually transistors but thermionic valves have seen historic use. The output of
12760-446: The time at which data is available varies: Because of this variety, and because diverse simulation systems have many common elements, there are a large number of specialized simulation languages . The best-known may be Simula . There are now many others. Systems that accept data from external sources must be very careful in knowing what they are receiving. While it is easy for computers to read in values from text or binary files, what
12876-517: The tool flow. If the scanned data matches the input data, then the tool flow has probably not introduced errors. The functional verification data are usually called test vectors . The functional test vectors may be preserved and used in the factory to test whether newly constructed logic works correctly. However, functional test patterns do not discover all fabrication faults. Production tests are often designed by automatic test pattern generation software tools. These generate test vectors by examining
12992-421: The whole mobility system, where humans (e.g., drivers, passengers, pedestrians), vehicles (e.g., connected vehicles, connected and automated vehicles), and traffics (e.g., traffic networks, traffic infrastructures) can seek guidance from their digital twins deployed on edge/ cloud servers to actuate real-time decisions. Computer simulation Computer simulation is the running of a mathematical model on
13108-460: The work of hundreds of engineers. Writing and debugging tool flows is an established engineering specialty in companies that produce digital designs. The tool flow usually terminates in a detailed computer file or set of files that describe how to physically construct the logic. Often it consists of instructions on how to draw the transistors and wires on an integrated circuit or a printed circuit board . Parts of tool flows are debugged by verifying
13224-474: Was first called "digital twin" by Hernández and Hernández in 1997. The digital twin concept consists of three distinct parts: the physical object or process and its physical environment, the digital representation of the object or process, and the communication channel between the physical and virtual representations. The connections between the physical version and the digital version include information flows and data that includes physical sensor flows between
13340-402: Was headed their way") much faster than by scanning tables of rain-cloud coordinates . Such intense graphical displays, which transcended the world of numbers and formulae, sometimes also led to output that lacked a coordinate grid or omitted timestamps, as if straying too far from numeric data displays. Today, weather forecasting models tend to balance the view of moving rain/snow clouds against
13456-483: Was immediately realized. Results of their work circulated around Bell Labs in the form of BTL memos before being published in 1957. At Shockley Semiconductor , Shockley had circulated the preprint of their article in December 1956 to all his senior staff, including Jean Hoerni , who would later invent the planar process in 1959 while at Fairchild Semiconductor . At Bell Labs, J.R. Ligenza and W.G. Spitzer studied
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