Contactless smart card
A contactless smart card is a contactless credential whose dimensions are credit-card size. Its embedded integrated circuits can store data and communicate with a terminal via NFC. Commonplace uses include bank cards and passports. There are two broad categories of contactless smart cards. Memory cards contain non-volatile memory storage components, some specific security logic. Contactless smart cards contain read-only RFID called CSN or UID, a re-writeable smart card microchip that can be transcribed via radio waves. A contactless smart card is characterized as follows: Dimensions are credit card size; the ID-1 of ISO/IEC 7810 standard defines them as 85.60 × 53.98 × 0.76 mm. Contains a security system with tamper-resistant properties and is capable of providing security services. Assets managed by way of a central administration systems, or applications, which receive or interchange information with the card, such as card hotlisting and updates for application data. Card data is transferred via radio waves to the central administration system through card read-write devices, such as point of sales devices, doorway access control readers, ticket readers, ATMs, USB-connected desktop readers, etc.
Contactless smart cards can be used for identification and data storage. They provide a means of effecting business transactions in a flexible, standard way with minimal human intervention. Contactless smart cards were first used for electronic ticketing in 1995 in South Korea. Since smart cards with contactless interfaces have been popular for payment and ticketing applications such as mass transit. Globally, contactless fare; the various standards emerging are local in focus and are not compatible, though the MIFARE Classic card from Philips has a large market share in the United States and Europe. In more recent times and MasterCard have agreed to standards for general "open loop" payments on their networks, with millions of cards deployed in the U. S. in Europe and around the world. Smart cards are being introduced in personal identification and entitlement schemes at regional and international levels. Citizen cards, drivers’ licenses, patient card schemes are becoming more prevalent. In Malaysia, the compulsory national ID scheme MyKad includes 8 different applications and is rolled out for 18 million users.
Contactless smart cards are being integrated into ICAO biometric passports to enhance security for international travel. Contactless smart card readers use radio waves to communicate with, both read and write data on a smart card; when used for electronic payment, they are located near PIN pads, cash registers and other places of payment. When the readers are used for public transit they are located on fare boxes, ticket machines and station platforms as a standalone unit; when used for security, readers are located to the side of an entry door. A contactless smart card is a card in which the chip communicates with the card reader through an induction technology similar to that of an RFID; these cards require only close proximity to an antenna to complete a transaction. They are used when transactions must be processed or hands-free, such as on mass transit systems, where a smart card can be used without removing it from a wallet; the standard for contactless smart card communications is ISO/IEC 14443.
It allows for communications at distances up to 10 cm. There had been proposals for ISO/IEC 14443 types C, D, E, F and G that have been rejected by the International Organization for Standardization. An alternative standard for contactless smart cards is ISO/IEC 15693, which allows communications at distances up to 50 cm. Examples of used contactless smart cards are Taiwan's EasyCard, Hong Kong's Octopus card, Shanghai's Public Transportation Card, South Korea's T-money, London's Oyster card, Beijing's Municipal Administration and Communications Card, Southern Ontario's Presto card, Japan Rail's Suica Card, the San Francisco Bay Area's Clipper Card, Melbourne's Myki Card, Sydney's Opal Card and India's More Card which predate the ISO/IEC 14443 standard; the following tables list smart cards used for public transportation and other electronic purse applications. A related contactless technology is RFID. In certain cases, it can be used for applications similar to those of contactless smart cards, such as for electronic toll collection.
RFID devices do not include writeable memory or microcontroller processing capability as contactless smart cards do. There are dual-interface cards that implement contactless and contact interfaces on a single card with some shared storage and processing. An example is Porto's multi-application transport card, called Andante, that uses a chip in contact and contactless mode. Like smart cards with contacts, contactless cards do not have a battery. Instead, they use a built-in inductor, using the principle of resonant inductive coupling, to capture some of the incident electromagnetic signal, rectify it, use it to power the card's electronics. Since the start of using the Seoul Transportation Card, numerous cities have moved to the introduction of contactless smart cards as the fare media in an automated fare collection system. In a number of cases these cards carry an electronic wallet as well as fare produ
Youth is the time of life when one is young, means the time between childhood and adulthood. It is defined as "the appearance, vigor, etc. characteristic of one, young". Its definitions of a specific age range varies, as youth is not defined chronologically as a stage that can be tied to specific age ranges. Youth is an experience that may shape an individual's level of dependency, which can be marked in various ways according to different cultural perspectives. Personal experience is marked by an individual's cultural norms or traditions, while a youth's level of dependency means the extent to which he still relies on his family and economically. Around the world, the English terms youth, teenager and young person are interchanged meaning the same thing, but they are differentiated. Youth can be referred to as the time of life; this involves childhood, the time of life, neither childhood nor adulthood, but rather somewhere in between. Youth identifies a particular mindset of attitude, as in "He is youthful".
For certain uses, such as employment statistics, the term sometimes refers to individuals from the ages of 14 to 21. However, the term adolescence refers to a specific age range during a specific developmental period in a person's life, unlike youth, a constructed category; the United Nations defines youth as persons between the ages of 15 and 24 with all UN statistics based on this range, the UN states education as a source for these statistics. The UN recognizes that this varies without prejudice to other age groups listed by member states such as 18–30. A useful distinction within the UN itself can be made between young adults. While seeking to impose some uniformity on statistical approaches, the UN itself is aware of contradictions between approaches in its own statutes. Hence under the 15–24 definition children are defined as those under the age of 14 while under the 1979 Convention on the Rights of the Child, those under the age of 18 are regarded as children; the UN states they are aware that several definitions exist for youth within UN entities such as Youth Habitat 15–32 and African Youth Charter 15–35.
Although linked to biological processes of development and aging, youth is defined as a social position that reflects the meanings different cultures and societies give to individuals between childhood and adulthood. The term in itself when referred to in a manner of social position, can be ambiguous when applied to someone of an older age with low social position. Scholars argue that age-based definitions have not been consistent across cultures or times and that thus it is more accurate to focus on social processes in the transition to adult independence for defining youth. "This world demands the qualities of youth: not a time of life but a state of mind, a temper of the will, a quality of imagination, a predominance of courage over timidity, of the appetite for adventure over the life of ease." – Robert KennedyYouth is the stage of constructing the self-concept. The self-concept of youth is influenced by variables such as peers, lifestyle and culture, it is a time of a person's life when their choices are most to affect their future.
In much of sub-Saharan Africa, the term "youth" is associated with young men from 15 to 30 or 35 years of age. Youth in Nigeria includes all members of the Federal Republic of Nigeria aged 18–35. Many African girls experience youth as a brief interlude between the onset of puberty and marriage and motherhood, but in urban settings, poor women are considered youth much longer if they bear children outside of marriage. Varying culturally, the gender constructions of youth in Latin America and Southeast Asia differ from those of sub-Saharan Africa. In Vietnam, widespread notions of youth are sociopolitical constructions for both sexes between the ages of 15 and 35. In Brazil, the term youth refers to people of both sexes from 15 to 29 years old; this age bracket reflects the influence on Brazilian law of international organizations like the World Health Organization. It is shaped by the notion of adolescence that has entered everyday life in Brazil through a discourse on children's rights; the intergovernmental organization Organisation for Economic Co-operation and Development defines youth as "those between 15 and 29 years of age".
August 12 was declared International Youth Day by the United Nations. Children's rights cover all the rights; when they grow up they are granted with new duties. There are different minimum limits of age at which youth are not free, independent or competent to take some decisions or actions; some of these limits are voting age, age of candidacy, age of consent, age of majority, age of criminal responsibility, drinking age, driving age, etc. After youth reach these limits they are free to vote, have sexual intercourse, buy or consume alcohol beverages or drive cars, etc. Voting age is the minimum age established by law that a person must attain to be eligible to vote in a public election; the age is set at 18 years. Studies show; this is an important right since, by voting they can support politics selected by themselves and not only by people of older generations. Age o
Bird vocalization includes both bird calls and bird songs. In non-technical use, bird songs are the bird sounds. In ornithology and birding, songs are distinguished by function from calls; the distinction between songs and calls is based upon complexity and context. Songs are longer and more complex and are associated with courtship and mating, while calls tend to serve such functions as alarms or keeping members of a flock in contact. Other authorities such as Howell and Webb make the distinction based on function, so that short vocalizations, such as those of pigeons, non-vocal sounds, such as the drumming of woodpeckers and the "winnowing" of snipes' wings in display flight, are considered songs. Still others require song to have syllabic diversity and temporal regularity akin to the repetitive and transformative patterns that define music, it is agreed upon in birding and ornithology which sounds are songs and which are calls, a good field guide will differentiate between the two. Bird song is best developed in the order Passeriformes.
Some groups are nearly voiceless, producing only percussive and rhythmic sounds, such as the storks, which clatter their bills. In some manakins, the males have evolved several mechanisms for mechanical sound production, including mechanisms for stridulation not unlike those found in some insects. Song is delivered from prominent perches, although some species may sing when flying; the production of sounds by mechanical means as opposed to the use of the syrinx has been termed variously instrumental music by Charles Darwin, mechanical sounds and more sonation. The term sonate has been defined as the act of producing non-vocal sounds that are intentionally modulated communicative signals, produced using non-syringeal structures such as the bill, tail and body feathers. In extratropical Eurasia and the Americas all song is produced by male birds; these differences have been known for a long time and are attributed to the much less regular and seasonal climate of Australian and African arid zones requiring that birds breed at any time when conditions are favourable, although they cannot breed in many years because food supply never increases above a minimal level.
With aseasonal irregular breeding, both sexes must be brought into breeding condition and vocalisation duetting, serves this purpose. The high frequency of female vocalisations in the tropics and Southern Africa may relate to low mortality rates producing much stronger pair-bonding and territoriality; the avian vocal organ is called the syrinx. The syrinx and sometimes a surrounding air sac resonate to sound waves that are made by membranes past which the bird forces air; the bird controls the pitch by changing the tension on the membranes and controls both pitch and volume by changing the force of exhalation. It can control the two sides of the trachea independently, how some species can produce two notes at once. One of the two main functions of bird song is mate attraction. Scientists hypothesize that bird song evolved through sexual selection, experiments suggest that the quality of bird song may be a good indicator of fitness. Experiments suggest that parasites and diseases may directly affect song characteristics such as song rate, which thereby act as reliable indicators of health.
The song repertoire appears to indicate fitness in some species. The ability of male birds to hold and advertise territories using song demonstrates their fitness. Therefore, a female bird may select males based on the quality of their songs and the size of their song repertoire; the second principal function of bird song is territory defense. Territorial birds will interact with each other using song to negotiate territory boundaries. Since song may be a reliable indicator of quality, individuals may be able to discern the quality of rivals and prevent an energetically costly fight. In birds with song repertoires, individuals may share the same song type and use these song types for more complex communication; some birds will respond to a shared song type with a song-type match. This may be an aggressive signal, however results are mixed. Birds may interact using repertoire-matches, wherein a bird responds with a song type, in its rival's repertoire but is not the song that it is singing; this may be a less aggressive act than song-type matching.
Song complexity is linked to male territorial defense, with more complex songs being perceived as a greater territorial threat. Communication through bird calls can be between individuals of the same species or across species. Birds communicate alarm through vocalizations and movements that are specific to the threat, bird alarms can be understood by other animal species, including other birds, in order to identify and protect against the specific threat. Mobbing calls are used to recruit individuals in an area where an owl or other predator may be present; these calls are characterized by wide-frequency spectra, sharp onset and termination, repetitiveness that are common across species and are believed to be helpful to other potential "mobbers" by being easy to locate. The alarm calls of most species, on the other hand, are characteristically high-pitched, making the caller difficult to locate. Individual birds may be sensitive enough to identify each other through their calls. Many birds t
San Diego Trolley
The San Diego Trolley is a light rail system operating in the metropolitan area of San Diego. It is known colloquially as "The Trolley"; the Trolley's operator, San Diego Trolley, Inc. is a subsidiary of the San Diego Metropolitan Transit System. The Trolley began service on July 26, 1981, making it the oldest of the "second-generation" light rail systems in the United States; the entire Trolley network serves 53 stations, comprises 53.5 miles of route, three primary lines named the Blue Line, the Orange Line, the Green Line, as well as a supplementary heritage streetcar downtown circulator known as the Silver Line that operates on select weekdays and holidays. In Q4 2014, the Trolley was the 5th most-ridden light rail system in the United States, with an average of 119,800 riders per weekday; the San Diego Trolley is operated by MTS, one of the oldest transit systems in Southern California dating back to the 1880s. Although its operating names have changed over the years, the two modes of transportation and trolleys, have remained consistent over most of the past 125 years.
San Diego Trolley used the same German-built Siemens–Duewag U2 vehicles as the Edmonton Light Rail Transit system in Edmonton and the C-Train in Calgary, Alberta and the Frankfurt U-Bahn in Frankfurt, Germany. The fleet has since been expanded to include Siemens SD-100 vehicles, most Siemens S70 vehicles. Although electric rail service in San Diego traces its roots back to 1891 when John D. Spreckels incorporated the San Diego Electric Railway, today's operating company, San Diego Trolley Incorporated, was not founded until 1980 when the Metropolitan Transit Development Board began planning a light-rail service along the Main Line of the San Diego and Arizona Eastern Railway, purchased by MTDB from Southern Pacific Railroad in 1979. Service began on July 19, 1981, with revenue collection beginning on July 26, 1981. 14 trains operated on a single line between Centre City or Downtown San Diego and San Ysidro, with stops in the cities of San Diego, National City, Chula Vista. On March 23, 1986, SDTI opened an extension east from Centre City San Diego to Euclid Avenue, along the La Mesa Branch of the SD&AE Railway – this new second line of the Trolley was called the East Line.
Service was extended along the same line to Spring Street on May 12, 1989 serving Lemon Grove, to La Mesa and on to El Cajon on June 23, 1989. Service from El Cajon to Santee, which does not operate along the old SD&AE right-of-way, began on August 26, 1995; the "Bayside" extension of the Trolley in Centre City San Diego opened on June 30, 1990. The first phase of the Old Town extension, from C Street to Little Italy in Centre City San Diego, opened on July 2, 1992; the second phase of that extension, running from Little Italy to Old Town, opened on June 16, 1996. The "Mission Valley West" SDTI extension from Old Town to Mission San Diego commenced service on November 23, 1997 – it was at this time that the former South Line and East Line of the system were renamed the Blue Line and the Orange Line, respectively; the "Mission Valley East" extension from Mission San Diego to La Mesa began operating on July 10, 2005, with the inauguration of the third line of the San Diego Trolley system, the Green Line.
The planning for the San Diego Trolley began in 1966 under the auspices of the Comprehensive Planning Organization, an intergovernmental agency of 13 cities and San Diego County. San Diego's streetcar system had been replaced with buses in 1949. In 1966 the local bus company, San Diego Transit, was facing public takeover; the CPO developed a mass-transit plan to address the long-range transportation issues of the metropolitan area. Little progress was made in the decade 1966–1975. CPO continued to research options for addressing the region's transportation needs. Several prominent stakeholders submitted their own mass-transit master plans for the region; the alternatives studied in the decade included: Restoration of the 1949 streetcar system for $1.3 billion BART-like system featuring 417 stations on a system of 284 miles for $2–5 billion Elevated system featuring automatic rapid transit vehicles for $1 billion Short demonstration light-rail line, for $20 million Express bus system on freewaysThe debate between rail rapid transit and light rail was conducted without reference to any specific right-of-way or railroad tracks.
The CPO's 1975 Regional Comprehensive Plan described a $1.5 billion rail-rapid transit system in San Diego featuring a system of 58 miles and 11 lines. However, by this time, it was acknowledged by public officials that the BART-like system would be much more expensive than light rail. Rail rapid plans were stalled due to high costs. Proponents of the rail rapid system were concerned about the low speed of at-grade streetcar systems. Operating deficits were a concern. A 1974 CPO study concluded that a streetcar system would incur operating deficits of $1.9 million annually. It was understood that any BART-like system would incur substantial deficits; the creation of the Metropolitan Transit Development Board in 1976 with a stated mission did not resolve differences between the many stakeholders. However, MTDB did analyze previous transit studies, determined that the guideway system should satisfy the following principles: Corridor should extend a long distance and offer high-speed operation Low capital cost designs should be adopted, to keep the costs within an affordable range Construction should be at-grade with exclusive right-of-way Operating deficits should be minimizedA feasibility study completed in 1975 identified
A ticket machine known as a ticket vending machine, is a vending machine that produces paper or electronic tickets, or recharges a stored-value card or smart card or the user's mobile wallet on a smartphone. For instance, ticket machines dispense train tickets at railway stations, transit tickets at metro stations and tram tickets at some tram stops and in some trams. Token machines may dispense the ticket in the form of a token which has the same function as a paper or electronic ticket; the typical transaction consists of a user using the display interface to select the type and quantity of tickets and choosing a payment method of either cash, credit/debit card or smartcard. The ticket are printed on paper and dispensed to the user, or loaded onto the user's smartcard or smartphone. To encourage usage of ticket machines and reduce the need for salespersons, machine prices may in some cases be lower than those at a ticket counter. In many countries where trains and urban transport tickets operate on the honor system, there are machines in stations for validating tickets.
This is for the situation where one decides to use it later. The ticket is time-stamped to determine its validity period. A common problem is forgetting to validate and being fined as if one had no ticket at all; such machines are not used in the United States. Nearly all American mass transit networks operating on the honor system expect their users to buy tickets before use. However, a handful of regional rail systems like Metrolink have adopted the use of validation machines for at least some ticket types. Ticket machines that are out of service or accept'exact change only' result in losses for transport providers. Ticket machines on trams in Melbourne, for example run out of change when passengers use a higher ratio of $2 and 50c coins, depleting the ticket machine of smaller coin denominations. Passengers do not need to buy tickets on trams. Ticket machines are often used for amusement parks, car parking, as well as those that issue free tickets — for example, those for virtual queueing. For most of the twentieth century, ticket machines issued paper tickets, or tokens worth one fare each.
Fare value was loaded onto stored-value cards. Passengers could load any amount within a range; the cards could be reloaded until their expiration date, again with any monetary amount within a given range. 1904: first self-service ticket machines on the Central London Railway, now part of London Underground 1954: Toronto Subway opens and has tokens in machines from day one 1977: San Diego-based airline PSA introduces vending machines for airline tickets Mechanical ticket machines were used by bus drivers and conductors since the late 1920s. Their functions may include recording of sales and payments; some manufacturers are TIM, Setright, AEG, CAMP, Gibson GFI Genfare, Xerox and Corvia. Since the 1970s, electronic computer terminals and printers are used. Handheld ticket machines are used on buses in India to sell tickets, validate smart cards and renew passes; these machines replaced the earlier manual fare collection system where tickets were punched to indicate journey and fare stages. List of tram and light-rail transit systems Self service Ticketing kiosk Winchester, Clarence, ed. "Ticket and change machines", Railway Wonders of the World, pp. 471–474 Illustrated description of these machines on the London Underground Financial Self Service Kiosk Solutions and Online Banking Services, Electronic Kiosks, 2014, retrieved February 20, 2014 - Financial services Kiosk
The Internet is the global system of interconnected computer networks that use the Internet protocol suite to link devices worldwide. It is a network of networks that consists of private, academic and government networks of local to global scope, linked by a broad array of electronic and optical networking technologies; the Internet carries a vast range of information resources and services, such as the inter-linked hypertext documents and applications of the World Wide Web, electronic mail and file sharing. Some publications no longer capitalize "internet"; the origins of the Internet date back to research commissioned by the federal government of the United States in the 1960s to build robust, fault-tolerant communication with computer networks. The primary precursor network, the ARPANET served as a backbone for interconnection of regional academic and military networks in the 1980s; the funding of the National Science Foundation Network as a new backbone in the 1980s, as well as private funding for other commercial extensions, led to worldwide participation in the development of new networking technologies, the merger of many networks.
The linking of commercial networks and enterprises by the early 1990s marked the beginning of the transition to the modern Internet, generated a sustained exponential growth as generations of institutional and mobile computers were connected to the network. Although the Internet was used by academia since the 1980s, commercialization incorporated its services and technologies into every aspect of modern life. Most traditional communication media, including telephony, television, paper mail and newspapers are reshaped, redefined, or bypassed by the Internet, giving birth to new services such as email, Internet telephony, Internet television, online music, digital newspapers, video streaming websites. Newspaper and other print publishing are adapting to website technology, or are reshaped into blogging, web feeds and online news aggregators; the Internet has enabled and accelerated new forms of personal interactions through instant messaging, Internet forums, social networking. Online shopping has grown exponentially both for major retailers and small businesses and entrepreneurs, as it enables firms to extend their "brick and mortar" presence to serve a larger market or sell goods and services online.
Business-to-business and financial services on the Internet affect supply chains across entire industries. The Internet has no single centralized governance in either technological implementation or policies for access and usage; the overreaching definitions of the two principal name spaces in the Internet, the Internet Protocol address space and the Domain Name System, are directed by a maintainer organization, the Internet Corporation for Assigned Names and Numbers. The technical underpinning and standardization of the core protocols is an activity of the Internet Engineering Task Force, a non-profit organization of loosely affiliated international participants that anyone may associate with by contributing technical expertise. In November 2006, the Internet was included on USA Today's list of New Seven Wonders; when the term Internet is used to refer to the specific global system of interconnected Internet Protocol networks, the word is a proper noun that should be written with an initial capital letter.
In common use and the media, it is erroneously not capitalized, viz. the internet. Some guides specify that the word should be capitalized when used as a noun, but not capitalized when used as an adjective; the Internet is often referred to as the Net, as a short form of network. As early as 1849, the word internetted was used uncapitalized as an adjective, meaning interconnected or interwoven; the designers of early computer networks used internet both as a noun and as a verb in shorthand form of internetwork or internetworking, meaning interconnecting computer networks. The terms Internet and World Wide Web are used interchangeably in everyday speech. However, the World Wide Web or the Web is only one of a large number of Internet services; the Web is a collection of interconnected documents and other web resources, linked by hyperlinks and URLs. As another point of comparison, Hypertext Transfer Protocol, or HTTP, is the language used on the Web for information transfer, yet it is just one of many languages or protocols that can be used for communication on the Internet.
The term Interweb is a portmanteau of Internet and World Wide Web used sarcastically to parody a technically unsavvy user. Research into packet switching, one of the fundamental Internet technologies, started in the early 1960s in the work of Paul Baran and Donald Davies. Packet-switched networks such as the NPL network, ARPANET, the Merit Network, CYCLADES, Telenet were developed in the late 1960s and early 1970s; the ARPANET project led to the development of protocols for internetworking, by which multiple separate networks could be joined into a network of networks. ARPANET development began with two network nodes which were interconnected between the Network Measurement Center at the University of California, Los Angeles Henry Samueli School of Engineering and Applied Science directed by Leonard Kleinrock, the NLS system at SRI International by Douglas Engelbart in Menlo Park, California, on 29 October 1969; the third site was the Culler-Fried Interactive Mathematics Center at the University of California, Santa Barbara, followed by the University of
According to many definitions, a disability is an impairment that may be cognitive, intellectual, physical, sensory, or some combination of these. Other definitions describe disability as the societal disadvantage arising from such impairments. Disability affects a person's life activities and may be present from birth or occur during a person's lifetime. Disabilities is an umbrella term, covering impairments, activity limitations, participation restrictions. An impairment is a problem in body structure. Disability is thus not just a health problem, it is a complex phenomenon, reflecting the interaction between features of a person’s body and features of the society in which he or she lives. Disability is a contested concept, with different meanings in different communities, it may be used to refer to physical or mental attributes that some institutions medicine, view as needing to be fixed. It may refer to limitations imposed on people by the constraints of an ableist society. Or the term may serve to refer to the identity of disabled people.
Physiological functional capacity is a related term that describes an individual's performance level. It gauges one's ability to perform the physical tasks of daily life and the ease with which these tasks are performed. PFC declines with advancing age to result in frailty, cognitive disorders or physical disorders, all of which may lead to labeling individuals as disabled; the discussion over disability's definition arose out of disability activism in the United States and the United Kingdom in the 1970s, which challenged how the medical concept of disability dominated perception and discourse about disabilities. Debates about proper terminology and their implied politics continue in disability communities and the academic field of disability studies. In some countries, the law requires that disabilities are documented by a healthcare provider in order to assess qualifications for disability benefits. For the purposes of the Americans with Disabilities Act of 1990, the Equal Employment Opportunity Commission regulations provide a list of conditions that should be concluded to be disabilities: deafness, blindness, an intellectual disability or missing limbs or mobility impairments requiring the use of a wheelchair, cancer, cerebral palsy, epilepsy, Human Immunodeficiency Virus infection, multiple sclerosis, muscular dystrophy, major depressive disorder, bipolar disorder, post-traumatic stress disorder, obsessive compulsive disorder, schizophrenia.
Contemporary understandings of disability derive from concepts that arose during the West's scientific Enlightenment. During the Middle Ages and other conditions were thought to be caused by demons, they were thought to be part of the natural order during and in the fallout of the Plague, which wrought impairments throughout the general population. In the early modern period there was a shift to seeking biological causes for physical and mental differences, as well as heightened interest in demarcating categories: for example, Ambroise Pare, in the sixteenth century, wrote of "monsters", "prodigies", "the maimed"; the European Enlightenment's emphases on knowledge derived from reason and on the value of natural science to human progress helped spawn the birth of institutions and associated knowledge systems that observed and categorized human beings. Contemporary concepts of disability are rooted in eighteenth- and nineteenth-century developments. Foremost among these was the development of clinical medical discourse, which made the human body visible as a thing to be manipulated and transformed.
These worked in tandem with scientific discourses that sought to classify and categorize and, in so doing, became methods of normalization. The concept of the "norm" developed in this time period, is signaled in the work of the Belgian statistician, sociologist and astronomer Adolphe Quetelet, who wrote in the 1830s of l'homme moyen – the average man. Quetelet postulated that one could take the sum of all people's attributes in a given population and find their average, that this figure should serve as a norm toward which all should aspire; this idea of a statistical norm threads through the rapid take up of statistics gathering by Britain, United States, the Western European states during this time period, it is tied to the rise of eugenics. Disability, as well as other concepts including: abnormal, non-normal, normalcy came from this; the circulation of these concepts is evident in the popularity of the freak show, where showmen profited from exhibiting people who deviated from those norms.
With the rise of eugenics in the latter part of the nineteenth century, such deviations were viewed as dangerous to the health of entire populations. With disability viewed as part of a person's biological make-up and thus their genetic inheritance, scientists turned their attention to notions of weeding such "deviations" out of the gene pool. Various metrics for assessing a person's genetic fitness, which were used to deport, sterilize, or institutionalize those deemed unfit. At the end of the Second World War, with the example of Nazi eugenics, eugenics faded from public discourse, d