A conceptual model is a representation of a system, made of the composition of concepts which are used to help people know, understand, or simulate a subject the model represents. It is a set of concepts; some models are physical objects. The term conceptual model may be used to refer to models which are formed after a conceptualization or generalization process. Conceptual models are abstractions of things in the real world whether physical or social. Semantic studies are relevant to various stages of concept formation. Semantics is about concepts, the meaning that thinking beings give to various elements of their experience; the term conceptual model is normal. It could mean "a model of concept" or it could mean "a model, conceptual." A distinction can be made between what models are made of. With the exception of iconic models, such as a scale model of Winchester Cathedral, most models are concepts, but they are intended to be models of real world states of affairs. The value of a model is directly proportional to how well it corresponds to a past, future, actual or potential state of affairs.
A model of a concept is quite different because in order to be a good model it need not have this real world correspondence. In artificial intelligence conceptual models and conceptual graphs are used for building expert systems and knowledge-based systems. Conceptual models range in type from the more concrete, such as the mental image of a familiar physical object, to the formal generality and abstractness of mathematical models which do not appear to the mind as an image. Conceptual models range in terms of the scope of the subject matter that they are taken to represent. A model may, for instance, represent a single thing, whole classes of things, very vast domains of subject matter such as the physical universe; the variety and scope of conceptual models is due to the variety of purposes had by the people using them. Conceptual modeling is the activity of formally describing some aspects of the physical and social world around us for the purposes of understanding and communication." A conceptual model's primary objective is to convey the fundamental principles and basic functionality of the system which it represents.
A conceptual model must be developed in such a way as to provide an understood system interpretation for the model's users. A conceptual model, when implemented properly, should satisfy four fundamental objectives. Enhance an individual's understanding of the representative system Facilitate efficient conveyance of system details between stakeholders Provide a point of reference for system designers to extract system specifications Document the system for future reference and provide a means for collaborationThe conceptual model plays an important role in the overall system development life cycle. Figure 1 below, depicts the role of the conceptual model in a typical system development scheme, it is clear that if the conceptual model is not developed, the execution of fundamental system properties may not be implemented properly, giving way to future problems or system shortfalls. These failures do have been linked to; those weak links in the system design and development process can be traced to improper execution of the fundamental objectives of conceptual modeling.
The importance of conceptual modeling is evident when such systemic failures are mitigated by thorough system development and adherence to proven development objectives/techniques. As systems have become complex, the role of conceptual modelling has expanded. With that expanded presence, the effectiveness of conceptual modeling at capturing the fundamentals of a system is being realized. Building on that realization, numerous conceptual modeling techniques have been created; these techniques can be applied across multiple disciplines to increase the user's understanding of the system to be modeled. A few techniques are described in the following text, many more exist or are being developed; some used conceptual modeling techniques and methods include: workflow modeling, workforce modeling, rapid application development, object-role modeling, the Unified Modeling Language. Data flow modeling is a basic conceptual modeling technique that graphically represents elements of a system. DFM is a simple technique, like many conceptual modeling techniques, it is possible to construct higher and lower level representative diagrams.
The data flow diagram does not convey complex system details such as parallel development considerations or timing information, but rather works to bring the major system functions into context. Data flow modeling is a central technique used in systems development that utilizes the structured systems analysis and design method. Entity-relationship modeling is a conceptual modeling technique used for software system representation. Entity-relationship diagrams, which are a product of executing the ERM technique, are used to represent database models and information systems; the main components of the diagram are the relationships. The entities can represent objects, or events; the relationships are responsible for relating the entities to one another. To form a system process, the relationships are combined with the entities and any attr
International Standard Serial Number
An International Standard Serial Number is an eight-digit serial number used to uniquely identify a serial publication, such as a magazine. The ISSN is helpful in distinguishing between serials with the same title. ISSN are used in ordering, interlibrary loans, other practices in connection with serial literature; the ISSN system was first drafted as an International Organization for Standardization international standard in 1971 and published as ISO 3297 in 1975. ISO subcommittee TC 46/SC 9 is responsible for maintaining the standard; when a serial with the same content is published in more than one media type, a different ISSN is assigned to each media type. For example, many serials are published both in electronic media; the ISSN system refers to these types as electronic ISSN, respectively. Conversely, as defined in ISO 3297:2007, every serial in the ISSN system is assigned a linking ISSN the same as the ISSN assigned to the serial in its first published medium, which links together all ISSNs assigned to the serial in every medium.
The format of the ISSN is an eight digit code, divided by a hyphen into two four-digit numbers. As an integer number, it can be represented by the first seven digits; the last code digit, which may be 0-9 or an X, is a check digit. Formally, the general form of the ISSN code can be expressed as follows: NNNN-NNNC where N is in the set, a digit character, C is in; the ISSN of the journal Hearing Research, for example, is 0378-5955, where the final 5 is the check digit, C=5. To calculate the check digit, the following algorithm may be used: Calculate the sum of the first seven digits of the ISSN multiplied by its position in the number, counting from the right—that is, 8, 7, 6, 5, 4, 3, 2, respectively: 0 ⋅ 8 + 3 ⋅ 7 + 7 ⋅ 6 + 8 ⋅ 5 + 5 ⋅ 4 + 9 ⋅ 3 + 5 ⋅ 2 = 0 + 21 + 42 + 40 + 20 + 27 + 10 = 160 The modulus 11 of this sum is calculated. For calculations, an upper case X in the check digit position indicates a check digit of 10. To confirm the check digit, calculate the sum of all eight digits of the ISSN multiplied by its position in the number, counting from the right.
The modulus 11 of the sum must be 0. There is an online ISSN checker. ISSN codes are assigned by a network of ISSN National Centres located at national libraries and coordinated by the ISSN International Centre based in Paris; the International Centre is an intergovernmental organization created in 1974 through an agreement between UNESCO and the French government. The International Centre maintains a database of all ISSNs assigned worldwide, the ISDS Register otherwise known as the ISSN Register. At the end of 2016, the ISSN Register contained records for 1,943,572 items. ISSN and ISBN codes are similar in concept. An ISBN might be assigned for particular issues of a serial, in addition to the ISSN code for the serial as a whole. An ISSN, unlike the ISBN code, is an anonymous identifier associated with a serial title, containing no information as to the publisher or its location. For this reason a new ISSN is assigned to a serial each time it undergoes a major title change. Since the ISSN applies to an entire serial a new identifier, the Serial Item and Contribution Identifier, was built on top of it to allow references to specific volumes, articles, or other identifiable components.
Separate ISSNs are needed for serials in different media. Thus, the print and electronic media versions of a serial need separate ISSNs. A CD-ROM version and a web version of a serial require different ISSNs since two different media are involved. However, the same ISSN can be used for different file formats of the same online serial; this "media-oriented identification" of serials made sense in the 1970s. In the 1990s and onward, with personal computers, better screens, the Web, it makes sense to consider only content, independent of media; this "content-oriented identification" of serials was a repressed demand during a decade, but no ISSN update or initiative occurred. A natural extension for ISSN, the unique-identification of the articles in the serials, was the main demand application. An alternative serials' contents model arrived with the indecs Content Model and its application, the digital object identifier, as ISSN-independent initiative, consolidated in the 2000s. Only in 2007, ISSN-L was defined in the
In software engineering, a domain model is a conceptual model of the domain that incorporates both behaviour and data. In ontology engineering, a domain model is a formal representation of a knowledge domain with concepts, datatypes and rules grounded in a description logic. A domain model is a system of abstractions that describes selected aspects of a sphere of knowledge, influence or activity; the model can be used to solve problems related to that domain. The domain model is a representation of meaningful real-world concepts pertinent to the domain that need to be modeled in software; the concepts include the data involved in the business and rules the business uses in relation to that data. A domain model uses the vocabulary of the domain, thus allowing a representation of the model to be communicated to non-technical stakeholders, it should not refer to any technical implementations such as databases or software components that are being designed. A domain model is implemented as an object model within a layer that uses a lower-level layer for persistence and "publishes" an API to a higher-level layer to gain access to the data and behavior of the model.
In the Unified Modeling Language, a class diagram is used to represent the domain model. Domain-driven design Domain layer Feature-driven development Logical data model Problem domain Domain driven development Domain Modelling article
Information technology is the use of computers to store, retrieve and manipulate data, or information in the context of a business or other enterprise. IT is considered to be a subset of communications technology. An information technology system is an information system, a communications system or, more speaking, a computer system – including all hardware and peripheral equipment – operated by a limited group of users. Humans have been storing, retrieving and communicating information since the Sumerians in Mesopotamia developed writing in about 3000 BC, but the term information technology in its modern sense first appeared in a 1958 article published in the Harvard Business Review. We shall call it information technology." Their definition consists of three categories: techniques for processing, the application of statistical and mathematical methods to decision-making, the simulation of higher-order thinking through computer programs. The term is used as a synonym for computers and computer networks, but it encompasses other information distribution technologies such as television and telephones.
Several products or services within an economy are associated with information technology, including computer hardware, electronics, internet, telecom equipment, e-commerce. Based on the storage and processing technologies employed, it is possible to distinguish four distinct phases of IT development: pre-mechanical, electromechanical, electronic; this article focuses on the most recent period, which began in about 1940. Devices have been used to aid computation for thousands of years initially in the form of a tally stick; the Antikythera mechanism, dating from about the beginning of the first century BC, is considered to be the earliest known mechanical analog computer, the earliest known geared mechanism. Comparable geared devices did not emerge in Europe until the 16th century, it was not until 1645 that the first mechanical calculator capable of performing the four basic arithmetical operations was developed. Electronic computers, using either valves, began to appear in the early 1940s.
The electromechanical Zuse Z3, completed in 1941, was the world's first programmable computer, by modern standards one of the first machines that could be considered a complete computing machine. Colossus, developed during the Second World War to decrypt German messages, was the first electronic digital computer. Although it was programmable, it was not general-purpose, being designed to perform only a single task, it lacked the ability to store its program in memory. The first recognisably modern electronic digital stored-program computer was the Manchester Baby, which ran its first program on 21 June 1948; the development of transistors in the late 1940s at Bell Laboratories allowed a new generation of computers to be designed with reduced power consumption. The first commercially available stored-program computer, the Ferranti Mark I, contained 4050 valves and had a power consumption of 25 kilowatts. By comparison the first transistorised computer, developed at the University of Manchester and operational by November 1953, consumed only 150 watts in its final version.
Early electronic computers such as Colossus made use of punched tape, a long strip of paper on which data was represented by a series of holes, a technology now obsolete. Electronic data storage, used in modern computers, dates from World War II, when a form of delay line memory was developed to remove the clutter from radar signals, the first practical application of, the mercury delay line; the first random-access digital storage device was the Williams tube, based on a standard cathode ray tube, but the information stored in it and delay line memory was volatile in that it had to be continuously refreshed, thus was lost once power was removed. The earliest form of non-volatile computer storage was the magnetic drum, invented in 1932 and used in the Ferranti Mark 1, the world's first commercially available general-purpose electronic computer. IBM introduced the first hard disk drive as a component of their 305 RAMAC computer system. Most digital data today is still stored magnetically on hard disks, or optically on media such as CD-ROMs.
Until 2002 most information was stored on analog devices, but that year digital storage capacity exceeded analog for the first time. As of 2007 94% of the data stored worldwide was held digitally: 52% on hard disks, 28% on optical devices and 11% on digital magnetic tape, it has been estimated that the worldwide capacity to store information on electronic devices grew from less than 3 exabytes in 1986 to 295 exabytes in 2007, doubling every 3 years. Database management systems emerged in the 1960s to address the problem of storing and retrieving large amounts of data and quickly. One of the earliest such systems was IBM's Information Management System, still deployed more than 50 years later. IMS stores data hierarchically, but in the 1970s Ted Codd proposed an alternative relational storage model based on set theory and predicate logic and the familiar concepts of tables and columns; the first commercially available relational database management system was available from Oracle in 1981. All database management systems consist of a number of components that together allow the data they store to be accessed simultan
The user interface, in the industrial design field of human–computer interaction, is the space where interactions between humans and machines occur. The goal of this interaction is to allow effective operation and control of the machine from the human end, whilst the machine feeds back information that aids the operators' decision-making process. Examples of this broad concept of user interfaces include the interactive aspects of computer operating systems, hand tools, heavy machinery operator controls, process controls; the design considerations applicable when creating user interfaces are related to or involve such disciplines as ergonomics and psychology. The goal of user interface design is to produce a user interface which makes it easy and enjoyable to operate a machine in the way which produces the desired result; this means that the operator needs to provide minimal input to achieve the desired output, that the machine minimizes undesired outputs to the human. User interfaces are composed of one or more layers including a human-machine interface interfaces machines with physical input hardware such a keyboards, game pads and output hardware such as computer monitors and printers.
A device that implements a HMI is called a human interface device. Other terms for human-machine interfaces are man–machine interface and when the machine in question is a computer human–computer interface. Additional UI layers may interact with one or more human sense, including: tactile UI, visual UI, auditory UI, olfactory UI, equilibrial UI, gustatory UI. Composite user interfaces are UIs that interact with two or more senses; the most common CUI is a graphical user interface, composed of a tactile UI and a visual UI capable of displaying graphics. When sound is added to a GUI it becomes a multimedia user interface. There are three broad categories of CUI: standard and augmented. Standard composite user interfaces use standard human interface devices like keyboards and computer monitors; when the CUI blocks out the real world to create a virtual reality, the CUI is virtual and uses a virtual reality interface. When the CUI does not block out the real world and creates augmented reality, the CUI is augmented and uses an augmented reality interface.
When a UI interacts with all human senses, it is called a qualia interface, named after the theory of qualia. CUI may be classified by how many senses they interact with as either an X-sense virtual reality interface or X-sense augmented reality interface, where X is the number of senses interfaced with. For example, a Smell-O-Vision is a 3-sense Standard CUI with visual display and smells; the user interface or human–machine interface is the part of the machine that handles the human–machine interaction. Membrane switches, rubber keypads and touchscreens are examples of the physical part of the Human Machine Interface which we can see and touch. In complex systems, the human–machine interface is computerized; the term human–computer interface refers to this kind of system. In the context of computing, the term extends as well to the software dedicated to control the physical elements used for human-computer interaction; the engineering of the human–machine interfaces is enhanced by considering ergonomics.
The corresponding disciplines are human factors engineering and usability engineering, part of systems engineering. Tools used for incorporating human factors in the interface design are developed based on knowledge of computer science, such as computer graphics, operating systems, programming languages. Nowadays, we use the expression graphical user interface for human–machine interface on computers, as nearly all of them are now using graphics. There is a difference between a user interface and an operator interface or a human–machine interface; the term "user interface" is used in the context of computer systems and electronic devices Where a network of equipment or computers are interlinked through an MES -or Host to display information. A human-machine interface is local to one machine or piece of equipment, is the interface method between the human and the equipment/machine. An operator interface is the interface method by which multiple equipment that are linked by a host control system is accessed or controlled.
The system may expose several user interfaces to serve different kinds of users. For example, a computerized library database might provide two user interfaces, one for library patrons and the other for library personnel; the user interface of a mechanical system, a vehicle or an industrial installation is sometimes referred to as the human–machine interface. HMI is a modification of the original term MMI. In practice, the abbreviation MMI is still used although some may claim that MMI stands for something different now. Another abbreviation is HCI, but is more used for human–computer interaction. Other terms used are operator interface terminal; however it is abbreviated, the terms refer to the'layer' that separates a human, operating a machine from the machine itself. Without a clean and usable interface, humans would not be able to