Eye tracking is the process of measuring either the point of gaze (where one is looking) or the motion of an eye relative to the head.  An eye tracker is a device for measuring eye positions and eye movement.  Eye trackers are used in research on the visual system, in psychology, in psycholinguistics, marketing, as an input device for human-computer interaction, and in product design.
In addition, eye trackers are increasingly being used for assistive and rehabilitative applications such as controlling wheelchairs, robotic arms, and prostheses. Recently, eye tracking has been examined as a tool for the early detection of autism spectrum disorder. There are several methods for measuring eye movement, with the most popular variant using video images to extract eye position.  Other methods use search coils or are based on the electrooculogram.

History

In the 1800s, studies of eye movement were made using direct observations. For example, Louis Émile Javal observed in 1879 that reading does not involve a smooth sweeping of the eyes along the text, as previously assumed, but a series of short stops (called fixations) and quick saccades.  This observation raised important questions about reading, questions which were explored during the 1900s: On which words do the eyes stop? For how long? When do they regress to already seen words?

Edmund Huey built an early eye tracker, using a sort of contact lens with a hole for the pupil. The lens was connected to an aluminum pointer that moved in response to the movement of the eye. Huey studied and quantified regressions (only a small proportion of saccades are regressions), and he showed that some words in a sentence are not fixated.

The first non-intrusive eye-trackers were built by Guy Thomas Buswell in Chicago, using beams of light that were reflected on the eye, then recording on film. Buswell made systematic studies into reading and picture viewing.

In the 1950s, Alfred L. Yarbus performed eye tracking research, and his 1967 book is often quoted. He showed that the task given to a subject has a very large influence on the subject's eye movement. He also wrote about the relation between fixations and interest:

The cyclical pattern in the examination of pictures "is dependent on not only what is shown on the picture, but also the problem facing the observer and the information that he hopes to gain from the picture."

In the 1970s, eye-tracking research expanded rapidly, particularly reading research. A good overview of the research in this period is given by Rayner.

In 1980, Just and Carpenter formulated the influential Strong eye-mind hypothesis, that "there is no appreciable lag between what is fixated and what is processed". If this hypothesis is correct, then when a subject looks at a word or object, he or she also thinks about it (process cognitively), and for exactly as long as the recorded fixation. The hypothesis is often taken for granted by researchers using eye-tracking. However, gaze-contingent techniques offer an interesting option in order to disentangle overt and covert attentions, to differentiate what is fixated and what is processed.

During the 1980s, the eye-mind hypothesis was often questioned in light of covert attention, the attention to something that one is not looking at, which people often do. If covert attention is common during eye-tracking recordings, the resulting scan-path and fixation patterns would often show not where attention has been, but only where the eye has been looking, failing to indicate cognitive processing.

The 1980s also saw the birth of using eye-tracking to answer questions related to human-computer interaction. Specifically, researchers investigated how users search for commands in computer menus.  Additionally, computers allowed researchers to use eye-tracking results in real time, primarily to help disabled users.

More recently, there has been growth in using eye tracking to study how users interact with different computer interfaces. Specific questions researchers ask are related to how easy different interfaces are for users.  The results of the eye tracking research can lead to changes in design of the interface. Another recent area of research focuses on Web development. This can include how users react to drop-down menus or where they focus their attention on a website so the developer knows where to place an advertisement.

According to Hoffman, current consensus is that visual attention is always slightly (100 to 250 ms) ahead of the eye. But as soon as attention moves to a new position, the eyes will want to follow.

Specific cognitive processes still cannot be inferred directly from a fixation on a particular object in a scene. For instance, a fixation on a face in a picture may indicate recognition, liking, dislike, puzzlement etc. Therefore, eye tracking is often coupled with other methodologies, such as introspective verbal protocols.

Thanks to advancement in portable electronic devices, portable head-mounted eye trackers currently can achieve excellent performance and are being increasingly used in research and market applications targeting daily life settings. These same advances have led to increases in the study of small eye movements that occur during fixation, both in the lab and in applied settings.

In the 21st century, the use of artificial intelligence (AI) and artificial neural networks has become a viable way to complete eye-tracking tasks and analysis. In particular, the convolutional neural network lends itself to eye-tracking, as it is designed for image-centric tasks. With AI, eye-tracking tasks and studies can yield additional information that may not have been detected by human observers. The practice of deep learning also allows for a given neural network to improve at a given task when given enough sample data. This requires a relatively large supply of training data, however.

The potential use cases for AI in eye-tracking cover a wide range of topics from medical applications to driver safety to game theory and even education and  training applications.

Tracker types
Eye-trackers measure rotations of the eye in one of several ways, but principally they fall into one of three categories:
 measurement of the movement of an object (normally, a special contact lens) attached to the eye
 optical tracking without direct contact to the eye
 measurement of electric potentials using electrodes placed around the eyes.

Eye-attached tracking
The first type uses an attachment to the eye, such as a special contact lens with an embedded mirror or magnetic field sensor, and the movement of the attachment is measured with the assumption that it does not slip significantly as the eye rotates. Measurements with tight-fitting contact lenses have provided extremely sensitive recordings of eye movement, and magnetic search coils are the method of choice for researchers studying the dynamics and underlying physiology of eye movement. This method allows the measurement of eye movement in horizontal, vertical and torsion directions.

Optical tracking

The second broad category uses some non-contact, optical method for measuring eye motion. Light, typically infrared, is reflected from the eye and sensed by a video camera or some other specially designed optical sensor. The information is then analyzed to extract eye rotation from changes in reflections. Video-based eye trackers typically use the corneal reflection (the first Purkinje image) and the center of the pupil as features to track over time. A more sensitive type of eye-tracker, the dual-Purkinje eye tracker, uses reflections from the front of the cornea (first Purkinje image) and the back of the lens (fourth Purkinje image) as features to track. A still more sensitive method of tracking is to image features from inside the eye, such as the retinal blood vessels, and follow these features as the eye rotates. Optical methods, particularly those based on video recording, are widely used for gaze-tracking and are favored for being non-invasive and inexpensive.

Electric potential measurement
The third category uses electric potentials measured with electrodes placed around the eyes. The eyes are the origin of a steady electric potential field which can also be detected in total darkness and if the eyes are closed. It can be modelled to be generated by a dipole with its positive pole at the cornea and its negative pole at the retina. The electric signal that can be derived using two pairs of contact electrodes placed on the skin around one eye is called Electrooculogram (EOG). If the eyes move from the centre position towards the periphery, the retina approaches one electrode while the cornea approaches the opposing one. This change in the orientation of the dipole and consequently the electric potential field results in a change in the measured EOG signal. Inversely, by analysing these changes in eye movement can be tracked. Due to the discretisation given by the common electrode setup, two separate movement components – a horizontal and a vertical – can be identified. A third EOG component is the radial EOG channel, which is the average of the EOG channels referenced to some posterior scalp electrode. This radial EOG channel is sensitive to the saccadic spike potentials stemming from the extra-ocular muscles at the onset of saccades, and allows reliable detection of even miniature saccades.

Due to potential drifts and variable relations between the EOG signal amplitudes and the saccade sizes, it is challenging to use EOG for measuring slow eye movement and detecting gaze direction. EOG is, however, a very robust technique for measuring saccadic eye movement associated with gaze shifts and detecting blinks.
Contrary to video-based eye-trackers, EOG allows recording of eye movements even with eyes closed, and can thus be used in sleep research. It is a very light-weight approach that, in contrast to current video-based eye-trackers, requires low computational power, works under different lighting conditions and can be implemented as an embedded, self-contained wearable system. It is thus the method of choice for measuring eye movement in mobile daily-life situations and REM phases during sleep.  The major disadvantage of EOG is its relatively poor gaze-direction accuracy compared to a video tracker.  That is, it is difficult to determine with good accuracy exactly where a subject is looking, though the time of eye movements can be determined.

Technologies and techniques

The most widely used current designs are video-based eye-trackers. A camera focuses on one or both eyes and records eye movement as the viewer looks at some kind of stimulus. Most modern eye-trackers use the center of the pupil and infrared / near-infrared non-collimated light to create corneal reflections (CR). The vector between the pupil center and the corneal reflections can be used to compute the point of regard on surface or the gaze direction. A simple calibration procedure of the individual is usually needed before using the eye tracker.

Two general types of infrared / near-infrared (also known as active light) eye-tracking techniques are used: bright-pupil and dark-pupil. Their difference is based on the location of the illumination source with respect to the optics. If the illumination is coaxial with the optical path, then the eye acts as a retroreflector as the light reflects off the retina creating a bright pupil effect similar to red eye. If the illumination source is offset from the optical path, then the pupil appears dark because the retroreflection from the retina is directed away from the camera.

Bright-pupil tracking creates greater iris/pupil contrast, allowing more robust eye-tracking with all iris pigmentation, and greatly reduces interference caused by eyelashes and other obscuring features. It also allows tracking in lighting conditions ranging from total darkness to very bright.

Another, less used, method is known as passive light. It uses visible light to illuminate, something which may cause some distractions to users. Another challenge with this method is that the contrast of the pupil is less than in the active light methods, therefore, the center of iris is used for calculating the vector instead. This calculation needs to detect the boundary of the iris and the white sclera (limbus tracking). It presents another challenge for vertical eye movements due to obstruction of eyelids.

Eye-tracking setups vary greatly. Some are head-mounted, some require the head to be stable (for example, with a chin rest), and some function remotely and automatically track the head during motion.  Most use a sampling rate of at least 30 Hz. Although 50/60 Hz is more common, today many video-based eye trackers run at 240, 350 or even 1000/1250 Hz, speeds needed to capture fixational eye movements or correctly measure saccade dynamics.

Eye movements are typically divided into fixations and saccades – when the eye gaze pauses in a certain position, and when it moves to another position, respectively. The resulting series of fixations and saccades is called a scanpath. Smooth pursuit describes the eye following a moving object. Fixational eye movements include microsaccades: small, involuntary saccades that occur during attempted fixation. Most information from the eye is made available during a fixation or smooth pursuit, but not during a saccade.

Scanpaths are useful for analyzing cognitive intent, interest, and salience.  Other biological factors (some as simple as gender) may affect the scanpath as well. Eye tracking in human–computer interaction (HCI) typically investigates the scanpath for usability purposes, or as a method of input in gaze-contingent displays, also known as gaze-based interfaces.

Data presentation

Interpretation of the data that is recorded by the various types of eye-trackers employs a variety of software that animates or visually represents it, so that the visual behavior of one or more users can be graphically resumed. The video is generally manually coded to identify the AOIs (areas of interest) or recently using artificial intelligence. Graphical presentation is rarely the basis of research results, since they are limited in terms of what can be analysed - research relying on eye-tracking, for example, usually requires quantitative measures of the eye movement events and their parameters, The following visualisations are the most commonly used:

Animated representations of a point on the interface
This method is used when the visual behavior is examined individually indicating where the user focused their gaze in each moment, complemented with a small path that indicates the previous saccade movements, as seen in the image.

Static representations of the saccade path
This is fairly similar to the one described above, with the difference that this is static method. A higher level of expertise than with the animated ones is required to interpret this.

Heat maps
An alternative static representation, used mainly for the agglomerated analysis of the visual exploration patterns in a group of users. In these representations, the 'hot' zones or zones with higher density designate where the users focused their gaze (not their attention) with a higher frequency. Heat maps are the best known visualization technique for eyetracking studies.

Blind zones maps, or focus maps
This method is a simplified version of the heat maps where the visually less attended zones by the users are displayed clearly, thus allowing for an easier understanding of the most relevant information, that is to say, it provides more information about which zones were not seen by the users.

Saliency maps Similar to heat maps, a saliency map illustrates areas of focus by brightly displaying the attention-grabbing objects over an initially black canvas. The more focus is given to a particular object, the brighter it will appear.

Eye-tracking vs. gaze-tracking
Eye-trackers necessarily measure the rotation of the eye with respect to some frame of reference. This is usually tied to the measuring system. Thus, if the measuring system is head-mounted, as with EOG or a video-based system mounted to a helmet, then eye-in-head angles are measured. To deduce the line of sight in world coordinates, the head must be kept in a constant position or its movements must be tracked as well. In these cases, head direction is added to eye-in-head direction to determine gaze direction.
However, if the motion of the head is minor, the eye remains in constant position.

If the measuring system is table-mounted, as with scleral search coils or table-mounted camera (remote) systems, then gaze angles are measured directly in world coordinates. Typically, in these situations head movements are prohibited. For example, the head position is fixed using a bite bar or a forehead support. Then a head-centered reference frame is identical to a world-centered reference frame. Or colloquially, the eye-in-head position directly determines the gaze direction.

Some results are available on human eye movements under natural conditions where head movements are allowed as well. The relative position of eye and head, even with constant gaze direction, influences neuronal activity in higher visual areas.

Practice
A great deal of research has gone into studies of the mechanisms and dynamics of eye rotation, but the goal of eye tracking is most often to estimate gaze direction. Users may be interested in what features of an image draw the eye, for example. It is important to realize that the eye tracker does not provide absolute gaze direction, but rather can measure only changes in gaze direction. To determine precisely what a subject is looking at, some calibration procedure is required in which the subject looks at a point or series of points, while the eye tracker records the value that corresponds to each gaze position. (Even those techniques that track features of the retina cannot provide exact gaze direction because there is no specific anatomical feature that marks the exact point where the visual axis meets the retina, if indeed there is such a single, stable point.) An accurate and reliable calibration is essential for obtaining valid and repeatable eye movement data, and this can be a significant challenge for non-verbal subjects or those who have unstable gaze.

Each method of eye-tracking has advantages and disadvantages, and the choice of an eye-tracking system depends on considerations of cost and application. There are offline methods and online procedures like AttentionTracking. There is a trade-off between cost and sensitivity, with the most sensitive systems costing many tens of thousands of dollars and requiring considerable expertise to operate properly. Advances in computer and video technology have led to the development of relatively low-cost systems that are useful for many applications and fairly easy to use. Interpretation of the results still requires some level of expertise, however, because a misaligned or poorly calibrated system can produce wildly erroneous data.

Eye-tracking while driving a car in a difficult situation

The eye movement of two groups of drivers have been filmed with a special head camera by a team of the Swiss Federal Institute of Technology: Novice and experienced drivers had their eye-movement recorded while approaching a bend of a narrow road.
The series of images has been condensed from the original film frames to show 2 eye fixations per image for better comprehension.

Each of these stills corresponds to approximately 0.5 seconds in real time.

The series of images shows an example of eye fixations #9 to #14 of a typical novice and of an experienced driver.

Comparison of the top images shows that the experienced driver checks the curve and even has Fixation No. 9 left to look aside while the novice driver needs to check the road and estimate his distance to the parked car.

In the middle images, the experienced driver is now fully concentrating on the location where an oncoming car could be seen. The novice driver concentrates his view on the parked car.

In the bottom image the novice is busy estimating the distance between the left wall and the parked car, while the experienced driver can use their peripheral vision for that and still concentrate vision on the dangerous point of the curve: If a car appears there, the driver has to give way, i.e. stop to the right instead of passing the parked car.

More recent studies have also used head-mounted eye tracking to measure eye movements during real-world driving conditions.

Eye-tracking of younger and elderly people while walking

While walking, elderly subjects depend more on foveal vision than do younger subjects. Their walking speed is decreased by a limited visual field, probably caused by a deteriorated peripheral vision.

Younger subjects make use of both their central and peripheral vision while walking. Their peripheral vision allows faster control over the process of walking.

Applications
A wide variety of disciplines use eye-tracking techniques, including cognitive science; psychology (notably psycholinguistics; the visual world paradigm); human-computer interaction (HCI); human factors and ergonomics; marketing research and medical research (neurological diagnosis). Specific applications include the tracking eye movement in language reading, music reading, human activity recognition, the perception of advertising, playing of sports, distraction detection and cognitive load estimation of drivers and pilots and as a means of operating computers by people with severe motor impairment. In the field of virtual reality, eye tracking is used in head mounted displays for a variety of purposes including to reduce processing load by only rendering the graphical area within the user's gaze.

Commercial applications
In recent years, the increased sophistication and accessibility of eye-tracking technologies have generated a great deal of interest in the commercial sector. Applications include web usability, advertising, sponsorship, package design and automotive engineering. In general, commercial eye-tracking studies function by presenting a target stimulus to a sample of consumers while an eye tracker records eye activity. Examples of target stimuli may include websites, television programs, sporting events, films and commercials, magazines and newspapers, packages, shelf displays, consumer systems (ATMs, checkout systems, kiosks) and software. The resulting data can be statistically analyzed and graphically rendered to provide evidence of specific visual patterns. By examining fixations, saccades, pupil dilation, blinks and a variety of other behaviors, researchers can determine a great deal about the effectiveness of a given medium or product. While some companies complete this type of research internally, there are many private companies that offer eye-tracking services and analysis.

One field of commercial eye-tracking research is web usability. While traditional usability techniques are often quite powerful in providing information on clicking and scrolling patterns, eye-tracking offers the ability to analyze user interaction between the clicks and how much time a user spends between clicks, thereby providing valuable insight into which features are the most eye-catching, which features cause confusion and which are ignored altogether. Specifically, eye-tracking can be used to assess search efficiency, branding, online advertisements, navigation usability, overall design and many other site components. Analyses may target a prototype or competitor site in addition to the main client site.

Eye-tracking is commonly used in a variety of different advertising media. Commercials, print ads, online ads and sponsored programs are all conducive to analysis with current eye-tracking technology. One example is the analysis of eye movements over advertisements in the Yellow Pages. One study focused on what particular features caused people to notice an ad, whether they viewed ads in a particular order and how viewing times varied. The study revealed that ad size, graphics, color, and copy all influence attention to advertisements. Knowing this allows researchers to assess in great detail how often a sample of consumers fixates on the target logo, product or ad. Hence an advertiser can quantify the success of a given campaign in terms of actual visual attention. Another example of this is a study that found that in a search engine results page, authorship snippets received more attention than the paid ads or even the first organic result.

Yet another example of commercial eye-tracking research comes from the field of recruitment. A study analyzed how recruiters screen LinkedIn profiles and presented results as heat maps.

Safety applications
Scientists in 2017 constructed a Deep Integrated Neural Network (DINN) out of a Deep Neural Network and a convolutional neural network. The goal was to use deep learning to examine images of drivers and determine their level of drowsiness by "classify[ing] eye states." With enough images, the proposed DINN could ideally determine when drivers blink, how often they blink, and for how long. From there, it could judge how tired a given driver appears to be, effectively conducting an eye-tracking exercise. The DINN was trained on data from over 2,400 subjects and correctly diagnosed their states 96%-99.5% of the time. Most other artificial intelligence models performed at rates above 90%. This technology could ideally provide another avenue for driver drowsiness detection.

Game theory applications
In a 2019 study, a Convolutional Neural Network (CNN) was constructed with the ability to identify individual chess pieces the same way other CNNs can identify facial features. It was then fed eye-tracking input data from 30 chess players of various skill levels. With this data, the CNN used gaze estimation to determine parts of the chess board to which a player was paying close attention. It then generated a saliency map to illustrate those parts of the board. Ultimately, the CNN would combine its knowledge of the board and pieces with its saliency map to predict the players' next move. Regardless of the training dataset the neural network system was trained upon, it predicted the next move more accurately than if it had selected any possible move at random, and the saliency maps drawn for any given player and situation were more than 54% similar.

Assistive technology
People with severe motor impairment can use eye tracking for interacting with computers as it is faster than single switch scanning techniques and intuitive to operate. Motor impairment caused by Cerebral Palsy or Amyotrophic lateral sclerosis often affects speech, and users with Severe Speech and Motor Impairment (SSMI) use a type of software known as Augmentative and Alternative Communication (AAC) aid, that displays icons, words and letters on screen and uses text-to-speech software  to generate spoken output. In recent times, researchers also explored eye tracking to control robotic arms and powered wheelchairs. Eye tracking is also helpful in analysing visual search patterns, detecting presence of Nystagmus and detecting early signs of learning disability by analysing eye gaze movement during reading.

Aviation applications
Eye tracking has already been studied for flight safety by comparing scan paths and fixation duration to evaluate the progress of pilot trainees,  for estimating pilots' skills, for analyzing crew's joint attention and shared situational awareness. Eye tracking technology was also explored to interact with helmet mounted display systems and multi-functional displays in military aircraft. Studies were conducted to investigate the utility of eye tracker for Head-up target locking and Head-up target acquisition in Helmet mounted display systems (HMDS). Pilots' feedback suggested that even though the technology is promising, its hardware and software components are yet to be matured. Research on interacting with multi-functional displays in simulator environment showed that eye tracking can improve the response times and perceived cognitive load significantly over existing systems.  Further, research also investigated utilizing measurements of fixation and pupillary responses to estimate pilot's cognitive load. Estimating cognitive load can help to design next generation adaptive cockpits with improved flight safety. Eye tracking is also useful for detecting pilot fatigue.

Automotive applications
In recent time, eye tracking technology is investigated in automotive domain in both passive and active ways. National Highway Traffic Safety Administration measured glance duration for undertaking secondary tasks while driving and used it to promote safety by discouraging the introduction of excessively distracting devices in vehicles In addition to distraction detection, eye tracking is also used to interact with IVIS. Though initial research  investigated the efficacy of eye tracking system for interaction with HDD (Head Down Display), it still required drivers to take their eyes off the road while performing a secondary task. Recent studies investigated eye gaze controlled interaction with HUD (Head Up Display) that eliminates eyes-off-road distraction. Eye tracking is also used to monitor cognitive load of drivers to detect potential distraction. Though researchers explored different methods to estimate cognitive load of drivers from different physiological parameters, usage of ocular parameters explored a new way to use the existing eye trackers to monitor cognitive load of drivers in addition to interaction with IVIS.

Entertainment applications
The 2021 video game Before Your Eyes registers and reads the player's blinking, and uses it as the main way of interacting with the game.

Engineering applications
The widespread use of eye-tracking technology has shed light to its use in empirical software engineering in the most recent years. The eye-tracking technology and data analysis techniques are used to investigate the understandability of software engineering concepts by the researchers. These include the understandability of business process models, and diagrams used in software engineering such as UML activity diagrams and EER diagrams. Eye-tracking metrics such as fixation, scan-path, scan-path precision, scan-path recall, fixations on area of interest/relevant region are computed, analyzed and interpreted in terms of model and diagram understandability. The findings are used to enhance the understandability of diagrams and models with proper model related solutions and by improving personal related factors such as working-memory capacity, cognitive-load, learning style and strategy of the software engineers and modelers.

Cartographic applications
Cartographic research has widely adopted eye tracking techniques. Researchers have used them to see how individuals perceive and interpret maps. For example, eye tracking has been used to study differences in perception of 2D and 3D visualization, comparison of map reading strategies between novices and experts or students and their geography teachers, and evaluation of the cartographic quality of maps. Besides, cartographers have employed eye tracking to investigate various factors affecting map reading, including attributes such as color or symbol density. Numerous studies about the usability of map applications took advantage of eye tracking, too.

The cartographic community's daily engagement with visual and spatial data positioned it to contribute significantly to eye tracking data visualization methods and tools. For example, cartographers have developed methods for integrating eye tracking data with GIS, utilizing GIS software for further visualization and analysis. The community has also delivered tools for visualizing eye tracking data or a toolbox for the identification of eye fixations based on a spatial component of eye-tracking data.

Privacy concerns

With eye tracking projected to become a common feature in various consumer electronics, including smartphones, laptops and virtual reality headsets, concerns have been raised about the technology's impact on consumer privacy. With the aid of machine learning techniques, eye tracking data may indirectly reveal information about a user's ethnicity, personality traits, fears, emotions, interests, skills, and physical and mental health condition. If such inferences are drawn without a user's awareness or approval, this can be classified as an inference attack. Eye activities are not always under volitional control, e.g., "stimulus-driven glances, pupil dilation, ocular tremor, and spontaneous blinks mostly occur without conscious effort, similar to digestion and breathing". Therefore, it can be difficult for eye tracking users to estimate or control the amount of information they reveal about themselves.

See also

Eye tracking on the ISS
Foveated imaging
Mouse-Tracking
Screen reading

Notes

References

Romano Bergstrom, Jennifer (2014). Eye Tracking in User Experience Design. Morgan Kaufmann. .
Bojko, Aga (2013). Eye Tracking The User Experience (A Practical Guide to Research). Rosenfeld Media. .

Commercial eye tracking

Attention
Cognitive science
Articles containing video clips
Human eye
History of human–computer interaction
Market research
Multimodal interaction
Promotion and marketing communications
Usability
Vision
Web design
Applications of computer vision

Eye tracking


Mo or MO may refer to:

Arts and entertainment

Fictional characters
 Mo, a girl in the Horrible Histories TV series
 Mo, also known as Mortimer, in the novel Inkheart by Cornelia Funke
 Mo, in the webcomic Jesus and Mo
 Mo, the main character in the Mo's Mischief children's book series
 Mo, an ophthalmosaurus from The Land Before Time franchise
 MO (Maintenance Operator), a robot in the Filmation series Young Sentinels
 Mo, a main character in Zoey's Extraordinary Playlist
 M-O (Microbe Obliterator), a robot in the film WALL-E
 Mo the clown, a character played by Roy Rene, 20th-century Australian stage comedian
 Mo Effanga, in the BBC medical drama series Holby City
 Mo Harris, in the BBC soap opera EastEnders
 Little Mo Mitchell, in the BBC soap opera EastEnders

Films
  "Mo" (魔 demon), original title of The Boxer's Omen, a 1983 Hong Kong film
 Mo (2010 film), a television movie about British politician Mo Mowlam
 Mo (2016 film), a Tamil horror film

Music
 M.O. (album), a 2013 album by American hip hop artist Nelly
 M.O, an English pop trio
 MØ, a Danish singer
 The MO, a Dutch pop band
 Mo Awards, annual awards for Australian live entertainment
 Yamaha MO, a music synthesizer

Other arts and entertainment
 Mo (Oz), a fictional country in the book The Magical Monarch of Mo by L. Frank Baum
 Mo (TV series), a 2022 comedy-drama

Businesses and organizations
 Altria Group, formerly Philip Morris (New York Stock Exchange symbol MO)
 Calm Air (IATA airline designator MO), an airline based in Thompson, Manitoba, Canada
 Milicja Obywatelska, a state police institution in Poland from 1944 to 1990

Language
 Mo (kana), Romanisation of the Japanese kana も and モ
 Mo language (disambiguation)
 Moldavian language (deprecated ISO 639-1 language code "mo")

People
 Mo (given name)
 Emperor Mo (disambiguation), the posthumous name of various Chinese emperors
 Mo (Chinese surname)
 Mo (Korean surname)
 MØ, Danish singer songwriter Karen Marie Ørsted (born 1988)
 Mr. Mo (rapper), rapper, member of the group Jim Crow
 Mr. Mo (singer), member of the Danish band Kaliber
 Mo Twister, Filipino radio DJ and TV host Mohan Gumatay (born 1977)
 Mo Hayder, a pen name of British crime novelist Beatrice Clare Dunkel (1962–2021)
 Mo (wrestler), ring name of Robert Horne (born 1964), professional wrestler
 Mariano Rivera, Panamaian-American retired baseball player (born 1969), nicknamed "Mo"

Places

Norway
 Mo i Rana, a town in Rana municipality, Nordland county
 Mo, Agder, a village in Vegårshei municipality, Agder county
 Mo, Innlandet, a village in Nord-Odal municipality, Innlandet county
 Mo, Møre og Romsdal, a village in Surnadal municipality, Møre og Romsdal county
 Mo, Telemark, a former municipality in the old Telemark county
 Mo, Vestland, a village in Modalen municipality, Vestland county
 Mo Church (disambiguation), a list of several churches by this name in Norway

Elsewhere
 County Mayo, Ireland (vehicle plate code MO)
 Macau (ISO 3166-1 alpha-2 country code MO)
 Missouri, US (postal abbreviation)
 Moscow Oblast, Russia
 Province of Modena, Italy (vehicle plate code MO)

Religion
 Mo (divination), a traditional Tibetan Buddhist technique of divination
 Mo (religion), an animist religion of the Zhuang people of China
 Modern Orthodox Judaism, a movement that attempts to synthesize Orthodox Jewish values with the secular world

Science and technology

Computing
 .mo, country code top level domain of Macau
 Magneto-optical drive (magneto-optical storage), a data storage medium
 Microsoft Office, an office software suite
 Mode of operation, in encryption block ciphers
 Motivating operation, a term describing the effectiveness of consequences in operant conditioning

Other uses in science and technology
 Mo (grist mill) (磨), ancient Chinese stone implements used to grind grain into flour
 Magnus and Oberhettinger aka "Formulas and Theorems for the Functions of Mathematical Physics", a mathematics book on special functions
 Manual override, a mechanism wherein control is taken from an automated system and given to the user
 Metalorganics, also known as organometallics, in chemistry and materials science
 Molecular orbital, a mathematical function describing the wave-like behavior of an electron in a molecule
 Molybdenum, symbol Mo, a chemical element
 Momentary open (MO), a group of electrical switches

Vehicles
 MO-class small guard ship, a class of small ships produced before and during World War II for the Soviet Navy
 Morris Oxford MO, an automobile produced by Morris Motors of the United Kingdom from 1948 to 1954

Other uses
 Mo (Chinese zoology), a name that semantically changed from "giant panda", to "a mythical chimera", to "tapir"
 Modus operandi (abbreviation m.o.), Latin meaning "mode of operation"; distinctive behavior patterns of an entity
 Month (abbreviation mo.), a unit of time of approximately 30 days
 Operation Mo, or the Port Moresby Operation, a Japanese plan to take the Australian Territory of New Guinea during World War II
 Medical officer (disambiguation)
 The Australian English diminutive word for moustache

See also
 M0 (disambiguation)
 Meaux (disambiguation)
 mho, in physics, the reciprocal of the "ohm" unit of resistance
 Mø (disambiguation)
 Mobile (disambiguation)
 Moe (disambiguation)
 Moe's (disambiguation)
 Mohs (disambiguation)
 Mow (disambiguation)

Mo


Willibrordus Martinus Pancratius van der Aalst (born 29 January 1966) is a Dutch computer scientist and  full professor at RWTH Aachen University, leading the Process and Data Science (PADS) group. His research and teaching interests include information systems, workflow management, Petri nets, process mining, specification languages, and simulation. He is also known for his work on workflow patterns.

Biography
Born in Eersel, Netherlands, van der Aalst received an MSc in computing science in 1988 at the Technische Universiteit Eindhoven (TU/e), and a PhD in mathematics in 1992 with the thesis "Timed colored Petri nets and their application to logistics" under supervision of Jaap Wessels and Kees van Hee.

In 1992 he started working at the Eindhoven University of Technology as an assistant professor for the department of Mathematics and Computing Science, where he headed the Specification and Modeling of Information Systems (SMIS) research group. From 2000 to 2003, he was a part-time full professor at the Computing Science department. And from 2000 to 2006 he was head of the Information Systems department at the Technology Management department of TU/e. Since 2006 he has been full professor at the Department of Mathematics & Computer Science of the Eindhoven University of Technology. He also has a part-time appointment in the BPM group of Queensland University of Technology (QUT).

He has been a visiting professor on at Karlsruhe Institute of Technology (AIFB), the University of Georgia (LSDIS), Johann Wolfgang Goethe University Frankfurt am Main (WI-II), the University of Colorado (CTRG), Queensland University of Technology (CITI), Aarhus University (DAIMI), and Fondazione Bruno Kessler (FBK).

He is associate editor for several journals, including "IEEE Transactions on Services Computing", "IEEE Transactions on Industrial Informatics", "International Journal of Business Process Integration and Management", "International Journal on Enterprise Modelling and Information Systems Architectures", "Computers in Industry", and "Transactions on Petri Nets and Other Models of Concurrency".

He is series editor of "Lecture Notes in Business Information Processing" (LNBIP) by Springer, member of the editorial board of "Distributed and Parallel Databases" and "Business and Information Systems Engineering", and member of several steering committees, including "International Conference Series on Business Process Management" (chair), "International Conference Series on Application and Theory of Petri nets" and "International Workshop Series on Web Services and Formal Methods".  He is also a member of the Royal Holland Society of Sciences and Humanities (Koninklijke Hollandsche Maatschappij der Wetenschappen) and the Academy of Europe (Academia Europaea). Van der Aalst was elected member of the Royal Netherlands Academy of Arts and Sciences in 2014.

Work
Van der Aalst's research interest is in the fields of information systems, business process management, simulation, Petri nets, process models, workflow management systems, verification techniques, process mining, enterprise resource planning systems, computer supported cooperative work, web services, business process redesign, resource allocation and interorganizational business processes.

He is a strong supporter of open-source software. He initiated and led the development of:
the ProM framework, a process mining tool
YAWL, a workflow management system
and several other software tools including Declare, Woflan, XRL, etc.

He also initiated the workflow patterns initiative. This work influenced industry standards such as the Business Process Execution Language (BPEL), the Business Process Modeling Notation (BPMN), etc. Van der Aalst's ideas have also influenced various widely used commercial software tools such as Flower, Protos, Futura Reflect, Staffware, WebSphere, and ARIS.

Other scientific contributions of Van der Aalst are in the fields of Business Process Discovery, event-driven process chains, the Workflow Management Coalition and XPDL.

Van der Aalst is an ISI Highly Cited researcher. According to Google Scholar he is among the highest ranked computer scientists in the world. See H-index for computer science.

Publications
Van der Aalst has published in total more than 400 books, journal papers, book chapters, conference papers, and reports on these topics. Books, a selection:

 van der Aalst, Wil, and Kees Max Van Hee. Workflow management: models, methods, and systems. MIT press, 2002; 2004.
 Dumas, Marlon, Wil M. van der Aalst, and Arthur H. Ter Hofstede. Process-aware information systems: bridging people and software through process technology. John Wiley & Sons, 2005.
 van der Aalst, Wil. Process mining: discovery, conformance and enhancement of business processes. Springer Science & Business Media, 2011.

Articles, a selection:
 van der Aalst, Wil MP. "The application of Petri nets to workflow management." Journal of circuits, systems, and computers 8.01 (1998): 21–66.
 Wil van der Aalst, Arthur H.M. Hofstede, Bartek Kiepuszewski, and Alistair P. Barros (2003). "Workflow Patterns". In: Distributed and Parallel Databases 14 (1): pp. 5–51. .
 van der Aalst, Wil MP, Arthur HM Ter Hofstede, and Mathias Weske. "Business process management: A survey." Business process management. Springer Berlin Heidelberg, 2003. 1–12.
 van der Aalst, Wil MP, and Arthur HM Ter Hofstede. "YAWL: yet another workflow language." Information systems 30.4 (2005): 245–275.

References

External links
Homepage Wil van der Aalst at Eindhoven University of Technology.

1966 births
Living people
Dutch computer scientists
Information systems researchers
Eindhoven University of Technology alumni
Academic staff of the Eindhoven University of Technology
Enterprise modelling experts
Members of the Royal Netherlands Academy of Arts and Sciences
Members of Academia Europaea
Software engineering researchers
Academic staff of the University of Queensland
People from Eersel
Academic staff of RWTH Aachen University

Wil van der Aalst


In many team sports that involve scoring goals, the goalkeeper (sometimes termed goaltender, netminder, GK, goalie, or keeper) is a designated player charged with directly preventing the opposing team from scoring by blocking or intercepting opposing shots on goal. Such positions exist in bandy, rink bandy, camogie, association football, Gaelic football, international rules football, floorball, handball, hurling, field hockey, ice hockey, roller hockey, lacrosse, ringette, rinkball, water polo, and shinty, as well as in other sports.

In most sports that involve scoring in a net, rules apply to the goalkeeper that do not apply to other players. These rules are often instituted to protect the goalkeeper from being a target for dangerous or even violent actions. This is most apparent in sports such as ice hockey and lacrosse, where goalkeepers are required to wear special equipment like heavy pads and a face mask to protect their bodies from the impact of the playing object (e.g., a ball or puck).

In some sports, goalkeepers may have the same rights as other players; in association football, for example, the keeper is allowed to kick the ball just as any other player but may also use their hands to handle the ball in a restricted area. In other sports, goalkeepers may be limited in the actions they are allowed to take or the area of the field or rink where they may be; in the NHL, for example, goalkeepers may not play the puck in the restricted areas behind the net or take the puck across the red line.

Examples

Association football

In football, each team's goalkeeper (GK) defends their team's goal and has special privileges within the game. The goalkeeper's main job is to stop any penetration of the ball into the goal. The goalkeeper is the only player in the side who may use their hands and arms to catch, throw, and save the ball, but only within their own penalty area. Goalkeepers are required to wear a distinctive color jersey, separate from the referee's jersey color and either team's regular jersey color, so the referee can easily identify them. There are no other specific requirements, but goalkeepers are usually allowed to wear additional protective gear, such as padded clothing. Most goalkeepers also wear gloves to protect their hands and enhance their grip of the ball. Like every player on the pitch, they are required to wear shin guards.

The goalkeeper is allowed to catch the ball and is also allowed to punch or deflect the ball away from the goal. The goalkeeper generally has a significant advantage on a ball high in the air by raising their arms and play the ball before an attacker can attempt a header. When the keeper picks up the ball, they are allowed to kick it or throw it, or to place it on the ground and play it with their feet. The official Laws of the Game stipulate that the goalkeeper must redistribute the ball within six seconds after picking it up; however, referees often use their discretion as long as the goalkeeper is not obviously attempting to waste time. Once the keeper establishes possession of the ball, opposing players are not allowed to attempt to play the ball and must give the goalkeeper room to attempt a kick. Referees usually give an advantage to an unprotected goalkeeper if a ball is in the air and both the goalkeeper and a field player of the opposing team are challenging for the ball.

The 1936 death of Sunderland A.F.C. goalkeeper Jimmy Thorpe shaped the development of the rule by which players were no longer allowed to raise their foot to a goalkeeper with control of the ball in their arms. Despite winning the league that season, Sunderland's season was marked with tragedy after the young goalkeeper died as a result of a kick in the head and chest after he had picked up the ball following a backpass in a game against Chelsea at Roker Park. He continued to take part until the match finished, but collapsed at home afterwards and died in hospital four days later from diabetes mellitus and heart failure 'accelerated by the rough usage of the opposing team'.

Though the goalkeeper is generally allowed to use their hands in the penalty area, they are not allowed to use their hands on balls that have been deliberately kicked to them by a teammate (it does not have to go backwards). In such situations, the goalkeeper may play the ball with their feet but cannot pick it up. The rule applies only to a ball that is kicked. A ball that is headed or otherwise not kicked may be picked up by the goalkeeper without penalty. An infringement of this rule results in an indirect kick for the opposing team. A ball that is merely deflected by a teammate may still be picked up by the goalkeeper since a deflection is not a deliberate play. The "back-pass" rule has been followed in international football and in most professional and amateur leagues since the early 1990s, but leagues for younger players may choose not to enforce the rule . The back pass rule is listed in Law 12 of the Laws of the Game.

As the goalkeeper is usually the team's only player who can see the entire field, they often act as the organizer of the team when it is defending, such as on a free kick or a corner kick. This means the goalkeeper needs to be loud, with a voice that can project over the defensive area of the pitch. In turn, the players on their team need to be able to listen and respond to directions given to them.

Bandy

In bandy, the goalkeeper defends their team's goal and has specific privileges within the game, which is regulated in section 6 of the Bandy Playing Rules set up by the Federation of International Bandy The goalkeeper's main job is to stop any penetration of the ball into the goal. The goalkeeper is allowed to hold the ball for six seconds before they have to release it. They may drop it to a defender or chuck it directly into attack.

If the ball passes the goal line, it is followed by different actions: if a defender last touches the ball, the reaction is an own goal if the ball goes between the goalposts; if it passes outside the goalposts, the reaction is a corner stroke. If last touched by an attacker's stick and passes between the posts, the reaction is a goal or a disallowed goal (offside or an infringement from the attacking team). If the ball passes from an attacker over the goal line outside the goalposts, the goalkeeper may retrieve a new ball from a cage hanging on the goal's either side and put the new ball in play with no signal from the referees.

The goalkeeper is the only player who may use their hands to play the ball (although only within their own penalty area). According to Rule 6.1 the goalkeeper is required to wear a jersey with a different color from either team's jersey color to avoid confusion for the referee. Goalkeepers wear padded gloves to aid in catching the ball, large shinpads, a padded sweater, and a helmet with a face mask.

The goalkeeper is the only player in the team who can pass the ball to a teammate by aid of their skates. The team might have a reserve goalkeeper, and the two may switch at any time during the game, without the need to notify the referee. There is no time-out in bandy, but an exception is sometimes made when the goalkeeper is hurt, especially if they don't have a designated reserve keeper.

As the goalkeeper is usually the team's only player who can see the entire field, they often act as an organizer of the team when it is defending, especially for free strokes against them.

Broomball
The role of the goalie or goaltender in Broomball is to prevent the ball from entering the net using their broom and body. In official games they must wear a face protector and helmet in addition to the normal protective clothing used in the game. They are additionally allowed to use one blocker glove and leg guards. Most goaltender privileges only apply when inside the goal area, for example being allowed to close their hand over the ball or send it out of play. Goaltenders are not sent to the penalty bench for infractions; instead, another team member is nominated to take their place. Goaltenders may not cross the centre line or play the ball across it. Goaltender substitutions may be made at any stoppage as often as desired.

Czech handball

In Czech handball the goalkeeper is the only player allowed kick the ball during play, and only if defending a shot inside the goal area (other players may only have contact with the ball above the knee). Attackers may enter the goal area but not shoot from inside it. The goalkeeper may not enter the other team's defensive third. Goalkeepers take penalty throws when the ball goes out of play behind their goal area with no deflection from the goal. The referee must allow a change of goalkeepers before penalty and free throws. Goalkeepers must wear a different colour jersey from the other players.

Field hockey

In field hockey, the goalkeeper generally wears extensive protective equipment including helmet, face and neck guards, chest and leg padding, arm or elbow protectors, specific gloves (the left glove is designed purely to block the ball, the right glove also has this function but in addition is designed to permit the goalkeeper to hold and use his or her stick), lower leg guards (known as pads) and shoe covers (known as kickers). The gloves, pads and kickers are almost always made of special high density foam material that both protects the goalkeeper and has excellent rebound qualities.  The goalkeeper is also equipped with a stick; either one designed for goalies or one as used for normal play. Specialist goalkeeper sticks must conform to the same dimensional limitations as field players' sticks but are designed for optimal use with one hand and for blocking rather than hitting the ball. From 2007 teams may elect to play with 11 field players, and no-one has the privileges of a goalkeeper. If a goalkeeper is used, they fall into one of two categories: a fully equipped goalkeeper must wear a helmet, unless they are nominated to take a penalty stroke against the opposing goalkeeper, wear a different colored shirt and at least foot and leg guards (arm and upper-body protection is optional); or they may opt to wear only a helmet. The goalkeeper is allowed to use any part of their body to play or deflect the ball, although they can't obstruct its play (for example by lying on top of it), and they can only do so within the goal circle (or "D"). Outside the D they are subject to the same rules as field players and may only use their stick to play the ball. Goalkeepers who are wearing a helmet are not permitted to pass their team's 23 m line, with the exception of goalkeepers who take penalty strokes. However, a goalkeeper who has elected to wear only a helmet is permitted to remove it and provided it is not left on the field of play, they may take part in the game in any part of the pitch, and retain their goalkeeping privileges, even if they do not have time to replace the helmet before making a save. It is compulsory to wear a helmet when defending a penalty stroke or penalty corner.

Floorball

In floorball, the goalkeeper defends their team's goal and has specific rules to follow within the game. The goalkeeper is the only player who may use their hands to play the ball. Goalkeepers do not have sticks, and they move in the goal crease on their knees, attempting to save the shots on goal. When the goalkeeper has possession of the ball, they have 3 seconds to throw it back into the game. The goalkeeper may not control the ball outside of his crease, except when kicking it. Goalkeepers are an essential part of starting plays, as they can throw the ball for a quick offensive chance. When throwing, the ball has to touch the goalkeeper's own side first before crossing the center line. Goalkeepers are also important in organizing their team's games, as they see the whole field better. Any contact against the goalkeeper (slashing, interference etc.) will result in a free shot or a 2-minute penalty. Like in ice hockey, the goalkeeper may be substituted for an extra attacker, if a delayed penalty occurs, or if his team needs a goal to tie the game in the final moments of the game. Goalkeepers may score goals, although this is not the case in some leagues. In floorball games, more goals are often scored than in, for example, ice hockey, because of the extremely quick tempo of the game and fast shots.

The only mandatory equipment for goalkeepers are masks, goalie-shirts, goalie-pants and shoes. Most goalkeepers also wear gloves. They may also optionally wear other protective equipment, such as knee pads, elbow-guards, shin-guards, jocks and torso armor. In some junior/independent leagues, many goalkeepers don't even wear goalie-shirts, but hooded tops .

Gaelic football
In Gaelic football, the goalie's main task is to prevent a goal from being scored against his side by directly defending the team's goal. A goal occurs when the ball passes through the goal; the attacking team is awarded 3 points. The goalie is the only player who may handle the ball on the ground, and only inside the small rectangle.

Gridiron football
The term "goal-tend" was used in early descriptions of American football positions to describe the defensive position farthest back from the line of scrimmage. Eventually the term became obsolete and was replaced by the term defensive fullback, then to its modern term free safety (or punt returner in kicking situations) . Unlike in soccer or Gaelic football, the goal-tend/safety does not physically protect the goalposts, as they are elevated above the ground and mostly out of the reach of any player (the National Football League also explicitly outlawed goaltending in 1985; no such rule exists in other levels of the game ). Also, unlike other codes of football, goal-tends have no special ball-handling privileges.

One situation in which a goalkeeper-like responsibility can arise is in Canadian football, where a single point is awarded for a kicked ball that is not returned out of the end zone. While standard practice is for defending teams to concede the single point, situations often arise where conceding that point could jeopardize a lead. A goal-tend can thus be employed to recover the ball and either return it out of the end zone or, generally if it is in the closing seconds of a game, punt the ball back into play or out of bounds to ensure the point is not conceded.

Handball

In handball, the goalkeeper is the only player in the team who is allowed to stay in the 6-meter zone throughout the whole competition. A goalkeeper is allowed to save the ball with all parts of their body, including two hands, trunks, two legs and so on, only within the defending 6-meter zone.

Whenever the ball is left on the ground within the 6-meter zone, the goalkeeper owns the possession of the ball; while whenever the ball is in the air above the 6-meter zone, the opponent can still jump in to grasp the ball without stepping in the 6-meter zone.

A goalkeeper can participate in offense by long-passing the ball to a teammate in the opposing half court for a fast-break score. The common handball goalkeeper clothing includes a long-sleeve jersey, long trousers, and any body protection (such as base layer or protective cup) .

Hurling

In hurling, the goalkeeper's main task is to prevent a goal from being scored against their side by directly defending the team's goal. The goalkeeper also takes "puckouts" after a score or wide ball. A goal occurs when the ball passes through the goal; the attacking team is awarded 3 points. The goalkeeper has one specific rule pertaining to him, opposing players may not directly physically challenge the goalkeeper while they are in possession of the ball in the small parallelogram, while if the goalkeeper leaves the small parallelogram, they are subject to the same rules as all other players. The goalkeeper wears a different color jersey, e.g., if a team has blue jerseys with white font, the goalkeeper will wear a white jersey of the same design with blue font. Most goalkeepers use a specifc hurley with a wider bas (flat face) to aid shot-stopping .

Ice hockey

In ice hockey, goalkeepers are more commonly referred to as "goaltenders" or simply "goalies". They defend their team's goal zone (net) by stopping shots of the puck from entering the net, thus preventing the opposing team from scoring. The goaltender usually plays in or near the area in front of the net called the goal crease (often referred to simply as the crease or the net). Because of the power of shots, the goaltender wears specific equipment designed to protect the body from direct impact . As is true with most other sports, only one goaltender is allowed to be on the playing area for each team at any one time.

International rules football
In International rules football, a hybrid game between Australian rules football (which does not have a goalkeeper) and Gaelic football, the goalkeeper's main task is to prevent a goal from being scored. A goal occurs when the ball comes off any part of an attacking player and passes through the goal; the attacking team is awarded 6 points.

Lacrosse

Box lacrosse

Since the creation of indoor or box lacrosse in the 1930s, a unique form of lacrosse goaltender was formed for the different dynamics of lacrosse on an ice-less ice hockey pad.

Field lacrosse

In men's field lacrosse, the designated goalkeeper is allowed to have a stick from 40inches to 72inches long and the head of a goalkeeper's crosse may measure up to 12inches wide. This is significantly larger than field players' heads to assist in blocking shots. Once a goalkeeper makes a save and has control of the ball in his crosse (stick), he may only remain in possession of the ball inside the protective crease for four seconds (the length may depend on the level of play). Before the four seconds is up, the goalkeeper must either pass the ball or leave the crease. After leaving, he may not re-enter the crease with possession of the ball.

While inside the crease (nine feet in radius), offensive players may not make contact with the goalie or his stick. Doing so is declared "goalie interference" and is penalized by a free clear to the half field line. There is a significant difference between NCAA/MLL rules and international rules regarding a pass while the goalkeeper is inside the crease: under NCAA/MLL rules, contact with a goalie's stick while in the act of passing, even after the ball is released, is prohibited and considered interference. Under international rules, protection ends when possession ends .  Contact with a goalie's stick after the ball is released, is legal. A goalie is allowed to make contact with the ball with his hand, although he is not allowed to control it or pick it up.

In women's lacrosse, once a goalkeeper makes a save and has control of the ball in her crosse, she may remain in possession of the ball inside the crease for ten seconds. The interference rule is similar to men's lacrosse; unlike in the men's game, a woman goalkeeper is allowed to control or even pick up the ball in her hand.

In both men's and women's lacrosse, goalkeepers are required to wear a helmet and 4-point chinstrap, a throat protector, gloves, and a chest protector. Use of a protective cup is, for obvious reasons, required in the men's game; thigh pads and shin guards are also being required for women goalkeepers as of 2007 . Although they are permitted to, few goalkeepers elect to wear optional protective equipment, including elbow and shoulder pads, thigh pads and shin guards, and long sweatpants.

Netball

In netball, the role of the Goal Keeper (denoted GK) is to prevent opposing players from shooting. This can be done by deflecting and intercepting passes and shots, collecting rebound balls from failed shots, and strategically influencing opposing players' positions in the shooting circle. Only the positions Goalkeeper and Goal Defence are allowed within the opposing shooting circle, from within which all scoring shots must be taken by the other team's Goal Attack and Goal Shooter. The Goal Keeper usually defends the opposing team's Goal Shooter. In accordance with the general rules of netball, the Goalkeeper must be a minimum of three feet away from the landing foot position of a player in possession of the ball when attempting to block, otherwise an obstruction penalty pass/shot is awarded to the other side's player in which the Goal Keeper must stand by the player's side and out of play until the ball is thrown. The Goal Keeper must stay within the defensive third of the court.

Shinty
In shinty and women's shinty the goalkeeper is the only player allowed to touch the ball with their hands. However, this does not extend to catching or holding the ball and the legal move is described as a 'slap', and the exception only applies within the ten yard area. The goalkeeper, like the rest of the players, may also use the caman/stick, the chest, two feet together or one foot on the ground to block the ball. Goalkeepers must wear a different colour jersey from the other players.

Water polo

Goalkeepers in water polo are given specific rules to follow when inside the five-meter area including the ability to touch the ball with two hands, the ability to stand, and the ability to punch the ball with a clenched fist. However, the goalkeeper may not cross the half-distance line while non-goalkeeper players can.

The rule change in 2006, according to the NFHS 2006–2007 swimming/diving and water polo rulebook, made the four and seven-meter lines merge into a five-meter line. A goalie may now, under revised rules, go beyond the 5m line according to the field rules (one hand) and not pass the half line and use two hands.

The new cap rules resulted in a goalie cap must now be in quarters alternating red/dark for home and red/white for away, the goalie must be number 1, 13, or 15, and for females: a red swim cap must be worn under the goalie cap, a team's dark swim cap is no longer acceptable as it is hard to distinguish a goalie from field players if the official cap is off. USWP and NCAA rules vary slightly.

The water polo goalkeeper is the least protected goalkeeper without gloves or body protection.

Goalkeepers on coins and postage stamps
Goalkeepers are regarded as one of the hardest positions to play therefore they can have a huge impact on a countries culture. Goalkeepers have been used on some collectors' coins and medals such as the Austrian 5 euro 100 years of football coin that was minted on 12 May 2004. The coin depicts a successful shot by a footballer, shown in the background, with the ball just passing the Austrian goalkeeper, Samuel Ali (still in the air) into the goal.

References
FINA water polo rules

Sports terminology

Goalkeeper


A victimless crime is an illegal act that has no victim, as the act doesn't involve harm to anyone (apart from the person doing the crime). Criminalization of victimless acts is especially a contentious issue among those who identify with libertarianism.

Victimless crimes include things like possession of illegal drugs, owning guns, collecting rainwater in many cities, etc.

Crime

Victimless crime


The A. Everett Austin House is a historic house museum and National Historic Landmark at 130 Scarborough Street in Hartford, Connecticut. It was the home of Wadsworth Atheneum director Arthur Everett "Chick" Austin Jr. Chick Austin built the house in 1930 after seeing the Palladian Villas of the Veneto on his honeymoon. It was declared a National Historic Landmark in 1994, for its distinctive architectural style and for its association with Austin, the Atheneum's director 1927–1944.

The house is a neo-Palladian homage to Vincenzo Scamozzi's Villa Ferreti, built in 1596 in Dolo, Republic of Venice.

The house, only one room deep, is long and narrow, 86 feet in length by 18 feet in depth. In the front elevation, the central three-bay pedimented pavilion is flanked by four-bay wings. The bays are defined by shallow, two-story Ionic pilasters. The walls of the pavilion and wings are in the same plane, since the pavilion does not project. The planar effect is emphasized by the wall sheathing, which is flush boarding, tongue-in-groove. The twelve flat pilasters rise with entasis from bases of double torus moldings to stylized Ionic capitals. Two string courses, one at first-floor ceiling height, the other below second-floor window sills, establish a horizontal orientation to balance the strong upward thrust of the pilasters.

Four stone steps lead up to the double front door in the central bay of the pavilion. Above the door, a balustrade is suggested by half-round, vase-shaped balusters applied to the spandrel under the tall, double round-arched window. First- and second-floor windows in the flanking bays of the pavilion are blind. Windows in the wings are double casements, four panes high at the first floor, three at the second; two are blind at each floor. The pavilion pilasters support a plain architrave and pulvinated frieze. The pediment above is without embellishment in its tympanum, and is wider than the cross gable behind it. The entablature continues under the eaves of the cross-gable roof.

After Austin's departure from Hartford in 1946, Helen Goodwin Austin remained in residence. In 1985, she and her two children, David and Sarah Austin, donated the house to the Wadsworth Atheneum, which provides guided visits of the property.

It is among the homes featured in Bob Vila's Guide to Historic Homes: In Search of Palladio, a six-hour A&E Network study of the work and influence of the Renaissance architect  Andrea Palladio.  The house was restored in 2000.

See also

 List of National Historic Landmarks in Connecticut
 National Register of Historic Places listings in Hartford, Connecticut

References

External links

 A. Everett Austin House

Houses in Hartford, Connecticut
Historic house museums in Connecticut
National Historic Landmarks in Connecticut
Museums in Hartford, Connecticut
Houses completed in 1930
Houses on the National Register of Historic Places in Connecticut
National Register of Historic Places in Hartford, Connecticut
1930 establishments in Connecticut

A. Everett Austin House


The Downtown Norwich Historic District is a historic district representing the core of the downtown area of the city of Norwich, Connecticut in the United States. It was listed on the National Register of Historic Places in 1985.  It includes 115 contributing buildings and one other contributing structure over a  area.  Several buildings in the historic district are also individually listed on the National Register, including the Norwich Town Hall,  the Telephone Exchange Building and the Carroll Building.

Norwich was settled by English colonists in the 17th century, and its first wharf was built in 1684.  It developed rapidly as a shipping port, with economic activity focused near the waterfront at the confluence of the Shetucket, Yantic, and Thames Rivers.  The downtown developed as a linear area just north of the main port area, Main Street forming an east–west axis.  The oldest surviving commercial building dates to 1742, and the oldest house to 1745.  A major fire in the downtown in 1793 encouraged a shift to brick construction, but growth was squelched by the economic blockades associated with the War of 1812.  The downtown's architecture is consequently dominated by Greek Revival andlate 19th and early 20th century architecture, which was built when the city was an important point for the transshipment of goods by either rail or ship.  By this time, the city's economy had diversified to include banking, textiles, and other water-powered industry.  The downtown area includes many intact 18th and 19th-century buildings centered on the now-picturesque harbor.

See also
Neighborhoods of Norwich, Connecticut
National Register of Historic Places listings in New London County, Connecticut

References

Historic districts in New London County, Connecticut
National Register of Historic Places in New London County, Connecticut
Norwich, Connecticut
Historic districts on the National Register of Historic Places in Connecticut

Downtown Norwich Historic District


Alscheid () is a village in the commune of Kiischpelt, in northern Luxembourg.  , the village had a population of 47.

Alscheid gave its name to the former commune of Kautenbach until 17 April 1914, when the commune was given the name Kautenbach, after its largest town.  Kautenbach was merged with Wilwerwiltz to form Kiischpelt in 2006.

See also

 List of villages in Luxembourg

Kiischpelt
Villages in Luxembourg

Alscheid


Superpower collapse is the societal collapse of a superpower nation state. The term is most often used to describe the dissolution of the Soviet Union and the loss of the United Kingdom's superpower status through the decline of the British Empire.

Nevertheless, Russia, the successor of the Soviet Union, and the United Kingdom are still regarded as great powers today with permanent seats on the United Nations Security Council (UNSC). These include the United Kingdom continuing to hold global soft and hard power and Russia holding the largest nuclear weapons arsenal in the world.

Since the 2010s, some academics and proponents also consider the United States, which is today generally considered the sole superpower after the fall of the Soviet Union, as currently undergoing "Superpower fatigue" and may be on a trajectory of superpower collapse.

Examples

Soviet Union / Russia
Dramatic changes occurred in the Soviet Union and the Eastern Bloc during the 1980s and early 1990s, with perestroika and glasnost, the dramatic fall of the Berlin Wall in November 1989, and finally the dissolution of the Soviet Union in December 1991. As early as 1970, Andrei Amalrik had made predictions of Soviet collapse, and Emmanuel Todd made a similar prediction in 1976.

British Empire / United Kingdom
The British Empire was the world's foremost power throughout the late 18th and 19th centuries, and achieved its largest extent in the 20th century. During this time, the United Kingdom acquired nation-state ownership and direct rule over large areas of the world. Britain's global power originated from the Industrial Revolution and because of its geography as a large maritime power off the coast of Western Europe. British political, economic, social and cultural influences dramatically shaped and created significant changes globally.

However, as other nations industrialized and social and political changes took place in the Empire, the idea of colonization and imperialism fell out of favour. In addition, the consequences of fighting two world wars in the 20th century within a relatively short amount of time hastened the decline of the Empire. The movement for self-determination of Britain's colonies started in the late 19th century and was well underway by the 1920s, seen for example through the emergence of the Indian National Congress in 1885 and the Balfour Declaration of 1926. Self-determination and movements for independence represented significant changes in political and social ideology. This culminated in a rapid wave of decolonization in the decades after World War II. It has also been argued that World War II saw the emergence of new powers, such as the United States and the Soviet Union, who were hostile to traditional imperialism and hastened its decline.

The Suez Crisis of 1956 is considered by some commentators to be the beginning of the end of Britain's period as a superpower, but other commentators have pointed much earlier such as in World War I, the Depression of 1920-21, the Partition of Ireland, the return of the pound sterling to the gold standard at its prewar parity in 1925, the Fall of Singapore, the loss of wealth from World War II, the end of Lend-Lease Aid from the United States in 1945, the postwar Age of Austerity, the Winter of 1946–47, the beginning of decolonization and the independence of British India as other key points in Britain's decline and loss of superpower status.

The Suez Crisis in particular is regarded by historians to be a political and diplomatic disaster for the British Empire, as it led to large-scale international condemnation, including extensive pressure from the United States and Soviet Union. This forced the British and the French to withdraw in embarrassment and cemented the increasingly-bipolar Cold War politics between the Soviet Union and United States. In the 1960s, the movement for decolonization reached its peak, with remaining imperial holdings achieving independence, accelerating the transition from the British Empire to the Commonwealth of Nations. As the Empire continued to crumble, the home islands of the United Kingdom later experienced deindustrialization throughout the 1970s, coupled with high inflation and industrial unrest that unravelled the postwar consensus. This led to some economists to refer to Britain as the Sick Man of Europe. In 1976, the United Kingdom had to seek assistance from the International Monetary Fund (IMF) which it had previously ironically helped create, receiving funding of $3.9 billion, the largest-ever loan to be requested up until that point. In 1979, the country suffered major widespread strikes known as the Winter of Discontent. All these factors were seen by academics, economists and politicians as symbolising Britain's postwar decline. Lastly, the Handover of Hong Kong to China was seen by experts as the definitive end of the British Empire.

Nevertheless, the United Kingdom today has retained global soft power in the 21st century, including a formidable military. The United Kingdom continues to have a permanent seat on the UN Security Council alongside only four other powers, and is one of the nine nuclear powers. Its capital city, London, continues to be regarded as one of the pre-eminent cities in the world, being ranked as a global city by the Mori Foundation. In 2022, the United Kingdom was ranked the foremost European country in terms of soft power by Brand Finance. However, it has been assumed by economists that more recent economic difficulties since the 2010s exacerbated by Brexit, a cost-of-living crisis, political instabilities and industrial disputes and strikes may have caused further permanent damage and erosion to Britain's lingering power.

United States

During the Cold War, the United States fought many proxy wars against Soviet-supported Marxist-Leninist and socialist states, but after the Soviet Union's dissolution, the US found itself as the world's sole superpower and was even deemed by some political theorists to be the world's sole hyperpower. Political theoreticians of the neorealist philosophy (known by many as neoconservatives) self-styled as the Blue Team, increasingly view China as a military threat, but there are relatively-strong economic ties between the two powers. Blue Team members favor containment and confrontation with China and strong American support of Taiwan.

In After the Empire: The Breakdown of the American Order (2001), French sociologist Emmanuel Todd predicts the eventual decline and fall of the United States as a superpower. "After years of being perceived as a problem-solver, the US itself has now become a problem for the rest of the world." Since the 2010s, as a result of asymmetric polarization within the United States, as well as globally perceived U.S. foreign policy failures, and China's growing influence around the world, some academics and geopolitical experts have argued that the United States may already be experiencing a decay in its soft power around the world.

See also
 Amity-enmity complex
 Global policeman
 Potential superpower
 Hegemony
 Ideocracy
 Ideology
 State collapse

References

International relations terminology
Societal collapse
Colapse

Superpower collapse


An actor in the Unified Modeling Language (UML) "specifies a role played by a user or any other system that interacts with the subject."

"An Actor models a type of role played by an entity that interacts with the subject (e.g., by exchanging signals and data),
but which is external to the subject."

"Actors may represent roles played by human users, external hardware, or other subjects. Actors do not necessarily represent specific physical entities but merely particular facets (i.e., "roles") of some entities that are relevant to the specification of its associated use cases. A single physical instance may play the role of several different actors and a given actor may be played by multiple different instances."

UML 2 does not permit associations between Actors. The use of generalization/specialization relationship between actors is useful in modeling overlapping behaviours between actors and does not violate this constraint since a generalization relation is not a type of association.

Actors interact with use cases.

References

External links
 Illustration of actors in UML
 Actor in UML 2

Unified Modeling Language

Actor (UML)


Onychoteuthis meridiopacifica is a species of squid in the family Onychoteuthidae. Males become mature at 40 mm, and the species is believed to reach a maximum mantle length of 90 mm, the smallest species in the genus Onychoteuthis. The tentacular club reaches a length of 20-25% of the mantle length, and contains 16-19 club hooks. Arms reach 27-44% of the mantle length, and each contain 50-60 suckers. 8-12 nuchal folds are present on each side of the head. Its short, broad fins and the possession of a small number marginal suckers on the tentacular clubs of adults are distinguishing characteristics of this species. It is found off eastern Australia and probably extends into seas off Indonesia as well as east to Tonga and Vanuatu.

References

Squid
Molluscs described in 1990

Onychoteuthis meridiopacifica


Donald Duck is an American comic strip by the Walt Disney Company starring Donald Duck, distributed by King Features Syndicate. The first daily Donald Duck strip debuted in American newspapers on February 7, 1938. On December 10, 1939, the strip expanded to a Sunday page as well. Writer Bob Karp and artist Al Taliaferro worked together on the strip for more than 30 years. The strip ended in May 1995.

Starting in 2015, IDW Publishing's Library of American Comics imprint has been reprinting hardcover collections of the Donald Duck strip. As of 2019, five volumes of Donald Duck: The Complete Daily Newspaper Comics and two volumes of Donald Duck: The Complete Sunday Comics have been released.

Publication history
Disney artist Al Taliaferro was hired at the Walt Disney Studio in January 1931, and given the job of inking Floyd Gottfredson's art for the Mickey Mouse comic strip. When the Sunday topper strip Silly Symphony was created in January 1932, Taliaferro began inking that strip as well, for Earl Duvall's pencils. By June, Duvall moved on and Taliaferro handled all of the art duties for Silly Symphony.

In 1934, Taliaferro drew the Silly Symphony story arc based on the cartoon The Wise Little Hen, which featured the first appearance of Donald Duck as a secondary character. That story, which lasted on the Sunday pages from September to December 1934, gave Taliaferro a particular liking for the Duck's character. He pitched the idea of a Donald strip to Walt Disney, and Disney allowed him a trial run in the Silly Symphony comic. Finishing up a "The Three Little Pigs" adaptation, Taliaferro and writer Ted Osborne began an extended run of Donald Duck gag strips from August 30, 1936, to December 5, 1937.

Taliaferro then pitched the idea of moving Donald to his own solo comic strip to Roy O. Disney, who rejected it. Taliaferro then produced three weeks-worth of episodes for a Donald Duck comic strip, brought them to Roy Disney, and asked him to offer the strip to King Features Syndicate for publication. (King Features had syndicated all Disney comic strips up to this point.) Roy Disney was not particularly interested, but his brother Walt Disney could see potential in the project. Taliaferro's original sample stories were rejected due to having "weak gags". Taliaferro co-operated with writer Merrill De Maris to create new sample stories, but these were also rejected. Taliaferro then co-operated with writer Homer Brightman, and this time the sample stories were approved. Taliaferro's idea was greenlighted and the new Donald Duck comic strip was about to begin.

On February 2, 1938, the Donald Duck comic strip started appearing in daily newspapers. A Sunday version was added on December 10, 1939. Taliaferro's was the strip's main penciller, while Homer Brightman was its writer and came up with the gags. But Brightman was mostly a screenwriter, and in 1940 quit the comic strip and returned to writing plots for animated short films. Brightman was replaced by Bob Karp, who would serve as Taliaferro's main creative partner for the rest of his career. The inkers for the comic strip included Karl Karpé (1940-1942), Dick Moores (1942-1943), George Waiss (1943-1946), Manuel Gonzalez (1955-1957), Bill Wright (1960), Al Hubbard (1965), Kay Wright (1965), Ellis Erringer (1965-1967) and Frank Grundeen (1967-1968).

The strip was an immediate success. King Features Syndicate's promotional material bragged that Donald Duck was picked up by 203 papers in 12 weeks, "the all-time syndication record!"

Taliaferro retired from the daily comic strip on October 10, 1967. He kept working on the Sunday version of the strip until his death in February, 1969. Since 1967, Taliaferro's duties on the comic strip had mostly been handled by Frank Grundeen, who replaced Taliaferro as the main artist upon his retirement and death. Bob Karp remained the strip's main writer until his retirement in 1974, with his last Sunday strip published November 29, 1975. Grundeen stayed on the strip as artist until 1976; his last daily was published on May 22, and his last Sunday on June 20, 1976.

The Donald Duck comic strip continued with new writers and artists over the following decades. The strip was written by Greg Crosby from 1974 to 1980, and Bob Foster from 1980 to 1990. When Grundeen left in 1976, Frank Smith was the artist from 1976 to 1986.

A large team of artists worked on the strip in 1986 and 1987, including Jim Franzen, Daan Jippes, Ulrich Schröder, Jorgen Klubien, Rick Hoover, Jules Coenen, Bill Langley, Tony Strobl, Brian Lum and Ennis McNulty. The strip stabilized in May 1987 with Pete Alvarado on pencils and Larry Mayer on inks, until January 7, 1990.

In 1990, Bob Foster, Pete Alvarado and Larry Mayer, all left the strip, which went into reprints starting in January.

The daily strip started up again in May 1990 with Larry Knighton as writer and artist, and he resumed the Sunday strip in September 1990. Knighton took the opportunity to bring the classic Carl Barks cast into the strip, like Gladstone Gander and Gyro Gearloose, as well as non-Barks characters like Duckworth, Scrooge McDuck's butler from the DuckTales animated TV series.

Knighton continued until May 1995, when King Features ended production of new episodes, and started publishing reprints until the present.

Story and characters
While the Mickey Mouse comic strip was an adventure series, the Donald Duck comic strip continued to be a daily comedy series. Each episode featured Donald dealing with problems and humorous situations. Most of the strips featured stand-alone gags, although some ongoing plots were introduced. The strips often lacked dialogue.

Taliaferro and Karp started expanding the Donald Duck universe by introducing new supporting characters for the protagonist. On March 17, 1938, they introduced Bolivar, Donald's pet St. Bernard. The strip found humor in the fact that Bolivar rarely listens to his owner. Taliaferro reportedly drew inspiration from his own pet dog, which was a Scottish Terrier. Gus Goose, the "lazy and gluttonous" cousin of Donald, was introduced on May 9, 1938.

On 4 November 1940, Taliaferro and Karp introduced a comic strip version of Daisy Duck, as Donald's new neighbour and love interest. The character had been created by Carl Barks for the short film Mr. Duck Steps Out (1940).

Grandma Duck, Donald's grandmother, was introduced on September 27, 1943. Taliaferro based the character on his mother-in-law and her old-fashioned ways. Taliaferro's version of Grandma is a hard-working farmer, but out of touch with the technological progress of the world surrounding her.

A comic strip version of Scrooge McDuck was added by Taliaferro on February 13, 1951, and Ludwig Von Drake on September 25, 1961. Larry Knighton's run in the last five years of the strip eliminated Professor Von Drake from the cast; his last strip was December 31, 1989.

Donald's car, the 313, was designed by Taliaferro on July 1, 1938. It has been associated with the character ever since.

Characters
 Donald Duck
 Huey, Dewey & Louie (introduced in October 1937)
 Bolivar the St. Bernard (introduced in March 1938)
 Gus Goose (introduced in May 1938)
 Hortense the Ostrich (introduced in October 1938)
 Daisy Duck (introduced in November 1940)
 Grandma Duck (introduced in September 1943)
 Socrates M. Gosling (introduced in April 1944)
 Scrooge McDuck (introduced in February 1951)
 Donna Duck (introduced in August 1951)
 Ludwig von Drake (introduced in September 1961)
 Moby Duck (introduced in December 1971)
 Gyro Gearloose (introduced in August 1990)
 Gladstone Gander (introduced in August 1990)

Reprints and collections

Big Little Books
In the 1930s and '40s, Western Publishing published a very popular series of small hardcover books for children known as Big Little Books. These chunky, compact books featured a captioned illustration on one page, with a page of text on the facing page. The stories featured a wide assortment of popular characters, including a number of Disney stars, and Taliaferro's Silly Symphony and Donald Duck strips provided material for many books. A Donald Duck Big Little Book would contain about 15 "stories", at 20 pages each—which is enough to narrate each panel of a Taliaferro Sunday strip as a story.

The following Big Little Books were published based on Donald Duck comic strips:

 Donald Duck and His (Mis)Adventures (1937)
 Silly Symphony, Featuring Donald Duck (1937)
 Donald Duck Hunting for Trouble (1938)
 Donald Duck (Such a Life) (1939)
 Donald Forgets to Duck (1939)
 Donald Duck Gets Fed Up (1940)
 Donald Duck Says Such Luck!''' (1941)
 Donald Duck Sees Stars (1941)
 Donald Duck Headed for Trouble (1942)
 Donald Duck Off the Beam! (1943)
 Donald Duck Is Here Again (1944)

Comic books
In 1940, several Donald Duck strips were reprinted in Dell Comics' Four Color (1st series) issue #4, Donald Duck.

Disney's flagship comic book, Walt Disney's Comics and Stories, was launched in 1940, and relied on reprints of the Donald Duck and Mickey Mouse comic strips for most of the content. The comic strips were gradually phased out as the Disney artists started producing more original material.

The Library of American Comics
In 2015, IDW Publishing's imprint, The Library of American Comics, began releasing hardcover collections of the Donald Duck and Silly Symphony comic strips.

Donald's first appearance in Silly Symphony's adaptation of The Wise Little Hen was reprinted in the first volume of Silly Symphonies: The Complete Disney Classics in 2016; and later the original run of Silly Symphony Donald Duck gag strips followed in this series' second volume (2017).

The publishing of Donald Duck: The Complete Daily Newspaper Comics as a series started in 2015; by 2019, there have been five volumes released. The companion collection Donald Duck: The Complete Sunday Comics'' was later launched in 2016; so far, it has had two volumes published.

References

External links
 Donald Duck daily strips at the INDUCKS
 Donald Duck Sunday strips at the INDUCKS

American comic strips
Donald Duck comics
Disney comic strips
1938 comics debuts
1939 comics debuts
1995 comics endings
Humor comics

Donald Duck (comic strip)


The Fiat 1800 and 2100 are six-cylinder automobiles produced by Italian manufacturer Fiat between 1959 and 1968. Both models were introduced in 1959. A four-cylinder 1500-cc version, the 1500L, was added to the range in 1963, when the 2100 was replaced by the larger engined 2300. The 1800/2100 were designed by Fiat's own Dante Giacosa.

Fiat 1800 (1959-68)

The Fiat 1800 was introduced as a four-door sedan at the 1959 Geneva Salon. A few months later, the five-door Familiare (Station Wagon) was added to the lineup, one of a very limited number of factory offerings in this class in Europe at the time. The 1800 model had a six-cylinder in-line engine of 1795 cc and a power output of  delivered through a 4-speed manual transmission. Its maximum speed was, depending on the version, . This was replaced in 1961 with the 1800 model B: the engine output was now  and top speed between  and . The 1800 B also benefitted from disc brakes on all four wheels.

Fiat 2100 (1959-61)
The 2100 was a version with a bigger 2054 cc six-cylinder engine. Bore and stroke are . In autumn 1959, the 2100 Speciale was introduced with a lengthened wheelbase and different front grille. The Speciale was typically used by diplomats and for other representational purposes. Carrozzeria Francis Lombardi built a longer stretched version, but this could seat seven and was mainly intended for taxi use, although a limousine version called "President" was also available, mainly purchased by the Italian and Vatican states.

The 2100 was discontinued in Italy during 1961, when the Fiat 2300 became available.

Fiat 1500L (1963-68)

In 1963 Fiat used the body of Fiat 1800/2100 to create a new, less expensive model, the Fiat 1500L. To distinguish it from the 1300/1500 it used the designation 1500L (for 'Lunga, "long"). The car shared its more compact sibling's four-cylinder 1481 cc engine, delivering , which was increased to  in 1964 for the second series. A reduced-performance version was also offered, aimed at taxi drivers. This proved popular in southern Europe, equipped with a version of the 1481 cc petrol inline-four engine developing just 60 bhp: the low power engine permitted the transport of customers in comfort and space at urban speeds, without consuming too much fuel.

This version was made also by SEAT in Spain, where no other petrol version of the Fiat 1800/2100 was ever produced. It was badged simply SEAT 1500, since no equivalent of the smaller Fiat 1500 was produced by SEAT. Nearly 200,000 Seat 1500s were built until 1972.

It is estimated that total production in Italy of the Fiat 1800/2100 range is 150,000.

Derivatives

Abarth also proposed a sportier, 2+2 car based on the 2100. He discussed his plan with Fiat's Vice President Gaudenzio Bono in 1959 and it was arranged to supply Abarth with bare 2100 chassis and drivetrains. The chassis was strengthened and shortened, now on a  wheelbase, and was fitted with a bored out and tuned engine with an Abarth exhaust system and Dunlop disc brakes on all four wheels. The bodywork was designed by Giovanni Michelotti and executed by Allemano. The Abarth 2200 was available as a two-door coupé or convertible and was introduced at the Turin Auto Show in October–November 1959. The bore was increased to , which gave a displacement of 2162 cc. Along with an increased compression ratio and triple Weber 40 DCOE carburettors, maximum power increased to  at 6000 rpm, making for top speeds of  for the Coupé and Spider respectively. Unlike Fiat's column-shifted original, the Abarth 2200 had the shifter relocated to the floor. As originally presented, the Spider was given a different front end treatment of a rectilinear nature, with twin headlights mounted at an angle. This rather awkward looking arrangement was shortlived; during 1960 Abarth changed it to a single-headlight design similar to that of the Coupé.

The 2200 was fully handbuilt and changes were introduced continuously throughout the production run. The very first coupés are pillarless, unlike cars built after December 1959 which received filigrane B-pillars. Subtle changes took place at the front, while side marker lights were added, and grilles and bumpers were altered several times. Always expensive and from a brand best known for tiny racing machines, the 2200 was only ever built to order and in very small numbers, probably 28 examples. Of these, three examples were built with right-hand drive (two Coupés and one Spider) and delivered in the United Kingdom by Abarth's local concessionaire Tony Crook. At Turin in November 1960 and again at Geneva in March 1961, an updated design by  was shown. The Ellena design eschewed rear quarter glass in favor of longer doors and a wraparound rear windshield. At the front, a rectangular grille with rounded corners housed two additional driving lights.

In spite of the minuscule sales, Abarth updated their model at Turin 1961 after the 2100 on which it was based was replaced by the 2300, but the resulting Abarth 2400 was even less competitive in light of the appearance of Fiat's own 2300 Coupé.

Fiat went on to offer their own, Ghia-designed coupé of the succeeding 2300. This design was first shown in Turin in November 1960 as the Fiat 2100 S. Thanks to triple carburettors, the tuned engine produced . The prototype was built by Ghia's OSI subsidiary; by the time production started, Fiat had upgraded the 2100 to become the 2300 and all Ghia Coupés after the initial prototype were thus equipped.

Engines

References

Fiat Personenwagen, by Fred Steiningen, 1994.

2100
1960s cars
Cars introduced in 1959
Rear-wheel-drive vehicles
Sedans
Station wagons
Cars discontinued in 1968

Fiat 1800 and 2100