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Meghalaya Democratic Alliance
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The Meghalaya Democratic Alliance (MDA) was a coalition of political parties that formed the Government in the state of Meghalaya, India, after the Legislative Assembly elections in Meghalaya, 2003. It was headed by the Indian National Congress (INC), which was the party with the highest number of seats in the 7th Meghalaya Legislative Assembly. Chief Minister D. D. Lapang and the other ministers in the Government were all members of the MDA. D. D. Lapang also served as the Chairperson of the MDA.
Contents
[hide]
1 History
2 Initial support
3 Changes in constituents
4 Controversies
5 Demise of Alliance
6 References
7 External links
History[edit]
After the 2003 elections to Legislative Assembly, INC Member of the Legislative Assembly (MLA) D. D. Lapang was elected the leader of the Congress Legislative Party (CLP).
The Nationalist Congress Party (NCP) first made a bid to form the Government, but they gave up when they were unable to provide the Governor M.M. Jacob with sufficient number of MLAs to prove majority in the Assembly.[1]
The INC then formed the MDA along with other parties and independents opposed to the NCP and the Bharatiya Janata Party (BJP).
The MDA pledged to work for the state's economic development and also to provide stability of the government.[2]
With 40 members in the 60 member Assembly, Governor M.M. Jacob invited the MDA to form the Government. D. D. Lapang was sworn in as Chief Minister on 4 March 2003.
Initial support[edit]
At the time of its formation, the MDA included the following members:
Indian National Congress (INC) (22 MLAs)
United Democratic Party (UDP) (9 MLAs)
Meghalaya Democratic Party (MDP) (4 MLAs)
Khun Hynniewtrep National Awakening Movement (KHNAM) (2 MLAs)
independents (3 MLAs)
In addition, the Hill State People's Democratic Party (HPDP) had also expressed willingness to join the MDA, but their MLAs were not provided to the governor when the MDA staked its claim to form the Government. [3]
D. D. Lapang (INC) served as the chairperson of the MDA while Dr. Donkupar Roy (UDP) served as the deputy chairperson. Martle Mukhim (MDP) served as the treasurer and R. G. Lyngdoh (INC) served as the spokesperson.
Changes in constituents[edit]
Though the HPDP legislators were not in the initial list of legislators submitted to the governor, one of their MLAs Dr. F. A. Khonglam was sworn in as a minister on 4 March 2003. Effectively, this meant the MDA had additional support of 2 MLAs from HPDP, taking their total strength in the 60-member Assembly to 42.[4]
Later in 2003, one additional independent joined the MDA, taking the total number of independents supporting the MDA to 4, and the total strength of the MDA to 43.
On 16 December 2003, 6 legislators from the opposition NCP broke away from their party and formed a new party called the Meghalaya Nationalist Congress Party (MNCP). They then joined the MDA coalition increasing the strength of the coalition to 49. 4 of the 6 MNCP legislatures were given ministerial positions in the MDA Government.[5]
Controversies[edit]
In mid-2004, after the Indian general election, 2004, the NCP joined the INC-led United Progressive Alliance (UPA) to form the Government of India. It was believed that this decision, might result in the MDA being disbanded with an INC-NCP combination to form the new Government in Meghalaya. However, on 31 May 2004, D. D. Lapang confirmed that the regional MDA coalition would not be affected by the new alliance at the central Government.[6]
In mid-2006, internal conflicts with the Meghalaya Congress Legislative Party (CLP) led to D. D. Lapang resigning as the CLP leader and as the Chief Minister under orders from the Congress high command. His former protégé, J. D. Rymbai was elected new leader of the CLP and Chief Minister on 15 June 2006.[7] Despite the leadership change, the internal conflicts continued with both Lapang and Rymbai claiming majority support in the CLP. After less than a year in-charge, Rymbai was directed by the Congress high command to relinquish the position to Lapang after a secret confidence vote determined that Rymbai no longer had majority support. After refusing to comply with the high command directive for 5 days, Rymbai finally resigned on 10 March 2007.[8][9] Lapang was reelected as the CLP leader and was sworn in as Chief Minister on 10 March 2008.[10]
Demise of Alliance[edit]
In the lead up to the Meghalaya Legislative Assembly election, 2008 all the regional parties forming the MDA decided to run against the INC. The UDP, MDP, KHNAM and HPDP fielded candidates against INC and made corruption and government failure as their main election issues to garner votes against the INC.[11]
This effectively meant the quiet demise of the Meghalaya Democratic Alliance.
The MDA was effectively replaced by the Meghalaya United Alliance (MUA) after the 2008 elections as INC tried to form the Government with support from independents.[12]
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References[edit]
Jump up ^ "Meghalaya: NCP claim falls flat". Rediff.com. 3 March 2003. Retrieved 27 October 2011.
Jump up ^ "Meghalaya: Lapang elected MDA leader". Rediff.com. 4 March 2003. Retrieved 27 October 2011.
Jump up ^ [1][dead link]
Jump up ^ http://oldcontent.northeastplus.in/2232.html
Jump up ^ [2] Archived 26 April 2006 at the Wayback Machine.
Jump up ^ http://oldcontent.northeastplus.in/3509.html
Jump up ^ "Lapang out, Rymbai is new Meghalaya CM". The Indian Express. India. 16 June 2006. Retrieved 27 October 2011.
Jump up ^ "संजू को धमकी नहीं आशीर्वाद दिया:भारद्वाज". Samaylive.com. 2 April 2009. Retrieved 27 October 2011.
Jump up ^ "Meghalaya CM Rymbai finally resigns". Search.rediff.com. Retrieved 27 October 2011.
Jump up ^ "Boloji.com – A Study in Diversity – News, Views, Analysis, Literature, Poetry, Features – Express Yourself". News.boloji.com. Retrieved 27 October 2011.
Jump up ^ "Meghalaya goes to polls today | Key issues – India News – IBNLive". Ibnlive.in.com. Retrieved 27 October 2011.
Jump up ^ "Congress garners support of 3 independents in Meghalaya – Thaindian News". Thaindian.com. 11 March 2008. Retrieved 27 October 2011.
External links[edit]
Government of Meghalaya
Meghalaya Legislative Assembly
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Katie Leclerc
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Katie Leclerc
Katie Leclerc at O Holy Night in June 2011.
Born
Katie Lynn Leclerc
(1986-11-06) November 6, 1986 (age 30)
San Antonio, Texas, United States
Nationality
American
Other names
Kate
Occupation
Actress, Producer
Years active
2005–present
Known for
Switched at Birth
Spouse(s)
Brian Habecost (m. 2014; div. 2017)
Website
www.katieleclerc.com
Katie Lynn Leclerc (born November 6, 1986)[1] is an American actress. She has appeared on several television series, including Veronica Mars, Fashion House and The Big Bang Theory. In 2011, she was cast in the television show Switched at Birth, starring as Daphne Vasquez.
Contents
[hide]
1 Personal life
2 Career
3 Filmography
3.1 Film
3.2 Television
4 Awards and nominations
5 References
6 External links
Personal life[edit]
Katie Leclerc with Ryan Lane at a Dogs for the Deaf benefit in April 2013
Katie Leclerc was born in San Antonio, Texas, and grew up in Lakewood, Colorado. She is the youngest of three siblings.[2] She started learning American Sign Language at 17, before she found out she had a disorder which includes hearing loss. Her older sister also teaches ASL. http://www.sdentertainer.com/features/interviews/special-interview-abc-family-switched-birth-katie-leclerc/ |title=Special Interview with ABC Family "Switched At Birth" Katie Leclerc|work= San Diego Entertainer magazine|date= July 15, 2011|accessdate=July 15, 2011}}</ref> Both her father and older sister have Ménière's disease as well.[3]
She married longtime boyfriend Brian Habecost, a real estate salesman, on September 6, 2014.[4] In July 2017, Leclerc filed for divorce from her husband.[5]
Career[edit]
Katie Leclerc discovered her passion for acting in seventh grade when she got the lead role in a production of Annie.[6][7] She then moved to San Diego, to pursue theatre at Valley Center High School. She took part in commercials for Pepsi, Cingular, Comcast, and GE. In 2006, she was in the Rascal Flatts video "What Hurts the Most" as a student in the classroom. She started her television career when she guest-starred on Veronica Mars. Since then, she has acted in many other television shows. Her first main acting role was in the show Switched at Birth, where she plays Daphne Vasquez, a Deaf teenager who was given to the wrong family after birth.
"My agent submitted me for a nationwide casting call for the roles of Emmett and Daphne. I ended up getting a call back, and that's when I was asked to try a "Deaf accent." It's something we discussed in depth. We wanted to make sure my portrayal was respectful and done correctly. At the same time, we felt that using a Deaf accent would be a really strong choice for the character.[8]
Filmography[edit]
Film[edit]
Year
Title
Role
Notes
2006 Gravy Train Lydia Faye Short film
2009 Flying By Ally
2009 The Inner Circle Claire
2012 Seven Lanterns Rachel Hawthorne Short film
2015 The Ones Katie Post-production
2015 Mesmerized Kate Hawthorne Post-production
2015 Holiday Breakup Kelly
2016 Stars Are Already Dead Ireland Post-production
Television[edit]
Year
Title
Role
Notes
2005 Veronica Mars Crystal Episode: "Silence of the Lamb"
2006 Fashion House Sara Recurring role (4 episodes)
2007 Naked Trucker and T-Bones Show, TheThe Naked Trucker and T-Bones Show Tokersville Queen Episode: "Salute to America"
2007 Saints & Sinners Bride Episode: "Dance, Dance Revolution"
2008 Riches, TheThe Riches Teen Girl Episode: "Friday Night Lights"
2008 Ex List, TheThe Ex List Mila Episode: "Protect and Serve"
2010 Hard Times of RJ Berger, TheThe Hard Times of RJ Berger Deaf Girl Episode: "Lily Pad"
2011, 2017 Big Bang Theory, TheThe Big Bang Theory Emily Episodes: "The Wiggly Finger Catalyst", "The Emotion Detection Automation"
2011–2017 Switched at Birth Daphne Vasquez Lead role
2012 CSI: Crime Scene Investigation Christine Episode: "Play Dead"
2013 My Synthesized Life Amanda Episodes: "Amanda", "A Disturbance in the Force"
2013 The Confession Katie Lapp Television film
2014 Community Carol Episode: "Analysis of Cork-Based Networking"
2015 Cloudy With a Chance of Love Debbie Metcalfe Television film
2015 The Reckoning Katie Lapp/Katherine Mayfield Television film
2017 Confess Auburn Reed Web series
Awards and nominations[edit]
Year
Award
Work
Result
Ref
2011 Teen Choice Awards for Choice Breakout Star Switched at Birth Nominated [9]
2013 TwoCents TV Award for Drama Queens Switched at Birth Won [10]
References[edit]
Jump up ^ Katie Leclerc on IMDb
Jump up ^ "Katie Leclerc-Welcome (2011)". Retrieved June 14, 2011.
Jump up ^ "NY Post: Deaf actress Katie Leclerc unites hearing and deaf worlds on family drama, "Switched at Birth" (2011)". Retrieved June 14, 2011.
Jump up ^ "Switched at Birth's Katie Leclerc Is Engaged". Retrieved November 2, 2013.
Jump up ^ "Actress Katie Leclerc files for divorce from husband". TV3 (Ireland). July 27, 2017. Retrieved August 7, 2017.
Jump up ^ "Special Interview with ABC Family "Switched At Birth" Katie Leclerc". San Diego Entertainer magazine. July 15, 2011. Retrieved July 15, 2011.
Jump up ^ "Twitter@katieleclerc "how old were you…"". June 10, 2013. Retrieved July 10, 2013.
Jump up ^ "Ability Magazine: Katie Leclerc Interview with Chet Cooper" (2011)". Retrieved April 3, 2012.
Jump up ^ "Blake Lively Wins Choice TV Drama Actress The Teen Choice Awards! Here Are More Winners!". Hollywood Life. August 7, 2011. Retrieved June 21, 2014.
Jump up ^ Ng, Philiana (July 11, 2013). "2013 TwoCents TV Awards – Drama Categories". The Hollywood Reporter. Retrieved May 23, 2013.
External links[edit]
Wikimedia Commons has media related to Katie Leclerc.
Katie Leclerc on IMDb
Authority control
WorldCat Identities
VIAF: 221075021
LCCN: no2011191526
Retrieved from "https://en.wikipedia.org/w/index.php?title=Katie_Leclerc&oldid=798309922"
Categories:
American deaf actresses
American film actresses
American television actresses
1986 births
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Actresses from Colorado
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People from Lakewood, Colorado
People from Valley Center, California
21st-century American actresses
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This page was last edited on 1 September 2017, at 04:42.
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Ciliary muscle
From Wikipedia, the free encyclopedia
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Ciliary muscle
The choroid and iris. (Ciliary muscle is labeled near top.)
Details
Origin
1) longitudinal fibers → scleral spur; 2) circular fibers → encircle root of iris[1]
Insertion
1) longitudinal fibers → ciliary process, 2) circular fibers → encircle root of iris[1]
Artery
long posterior ciliary arteries
Vein
Vorticose vein
Nerve
short ciliary
From oculomotor nerve
Through ciliary ganglion
Sympathetic postganglionic fibers from sup. cervical ganglia.
Actions
1) accommodation, 2) regulation of trabecular meshwork pore sizes
Identifiers
Latin
musculus ciliaris
TA
A15.2.03.014
FMA
49151
Anatomical terms of muscle
[edit on Wikidata]
The ciliary muscle /ˈsɪli.ɛəri/ is a ring of smooth muscle[2][3] in the eye's middle layer (vascular layer) that controls accommodation for viewing objects at varying distances and regulates the flow of aqueous humour into Schlemm's canal. It changes the shape of the lens within the eye, not the size of the pupil which is carried out by the sphincter pupillae muscle and dilator pupillae.[citation needed]
Contents
[hide]
1 Structure
1.1 Development
1.2 Innervation
2 Function
2.1 Accommodation
2.2 Trabecular meshwork pore size
3 Clinical significance
3.1 Glaucoma
4 History
4.1 Etymology
5 Additional images
6 See also
7 References
8 Bibliography
9 External links
Structure[edit]
Development[edit]
The ciliary muscle develops from mesenchyme within the choroid and is considered a cranial neural crest derivative.[4]
Innervation[edit]
Ciliary ganglion with parasympathetic fibers of ciliary nerves.
The ciliary muscle receives parasympathetic fibers from the short ciliary nerves that arise from the ciliary ganglion. The sympathetic postganglionic fibers are part of cranial nerve V (Nasociliary nerve of the trigeminal).[5] The postganglionic sympathetic innervation arises from the superior cervical ganglia[6]
Presynaptic parasympathetic signals that originate in the Edinger-Westphal nucleus are carried by cranial nerve III (the oculomotor nerve) and travel through the ciliary ganglion via the postganglionic parasympathetics fibers which travel in the short ciliary nerves and supply the ciliary body and iris. Parasympathetic activation of the M3 muscarinic receptors causes ciliary muscle contraction, the effect of contraction is to decrease the diameter of the ring of ciliary muscle (causing constriction of the pupil and accommodation). The zonule fibers relax and the lens becomes more spherical, increasing its power to refract light for near vision.[citation needed]
The parasympathetic tone is dominant when a higher degree of accommodation of the lens is required, such as reading a book.[7]
Function[edit]
Accommodation[edit]
Main article: accommodation of the eye
The ciliary fibers have circular (Ivanoff),[8] longitudinal (meridional) and radial orientations.[9]
According to Hermann von Helmholtz's theory, the circular ciliary muscle fibers affect zonular fibers in the eye (fibers that suspend the lens in position during accommodation), enabling changes in lens shape for light focusing. When the ciliary muscle contracts, it pulls itself forward and moves the frontal region toward the axis of the eye. This releases the tension on the lens caused by the zonular fibers (fibers that hold or flatten the lens). This release of tension of the zonular fibers causes the lens to become more spherical, adapting to short range focus. Conversely, relaxation of the ciliary muscle causes the zonular fibers to become taut, flattening the lens, increasing the focal distance,[10] increasing long range focus. Although Helmholtz's theory has been widely accepted since 1855, its mechanism still remains controversial. Alternative theories of accommodation have been proposed by others, including L. Johnson, M. Tscherning, and especially Ronald A. Schachar.[2]
Trabecular meshwork pore size[edit]
Contraction and relaxation of the longitudinal fibers, which insert into the trabecular meshwork in the anterior chamber of the eye, cause an increase and decrease in the meshwork pore size, respectively, facilitating and impeding aqueous humour flow into the canal of Schlemm.[11]
Clinical significance[edit]
Glaucoma[edit]
Open-angle glaucoma (OAG) and closed-angle glaucoma (CAG) may be treated by muscarinic receptor agonists (e.g., pilocarpine), which cause rapid miosis and contraction of the ciliary muscles, opening the trabecular meshwork, facilitating drainage of the aqueous humour into the canal of Schlemm and ultimately decreasing intraocular pressure.[12]
History[edit]
Etymology[edit]
The word ciliary had its origins around 1685–1695.[13] The term cilia originated a few years later in 1705–1715, and is the Neo-Latin plural of cilium meaning eyelash. In Latin, cilia means upper eyelid and is perhaps a back formation from supercilium, meaning eyebrow. The suffix -ary originally occurred in loanwords from Middle English (-arie), Old French (-er, -eer, -ier, -aire, -er), and Latin (-ārius); it can generally mean "pertaining to, connected with", "contributing to", and "for the purpose of".[14] Taken together, cili(a)-ary pertains to various anatomical structures in and around the eye, namely the ciliary body and annular suspension of the lens of the eye.[15]
Additional images[edit]
The arteries of the choroid and iris. The greater part of the sclera has been removed.
Iris, front view.
See also[edit]
This article uses anatomical terminology; for an overview, see Anatomical terminology.
Accommodation reflex
Ciliary body
Cycloplegia
Presbyopia
References[edit]
^ Jump up to: a b Gest, Thomas R; Burkel, William E. "Anatomy Tables - Eye." Medical Gross Anatomy. 2000. University of Michigan Medical School. January 5, 2010 Umich.edu Archived 2010-05-26 at the Wayback Machine.
^ Jump up to: a b Kleinmann, G; Kim, H. J.; Yee, R. W. (2006). "Scleral expansion procedure for the correction of presbyopia". International ophthalmology clinics. 46 (3): 1–12. PMID 16929221.
Jump up ^ Schachar, Ronald A. (2012). "Anatomy and Physiology." (Chapter 4) The Mechanism of Accommodation and Presbyopia. Kugler Publications. ISBN 978-9-062-99233-1.
Jump up ^ Dudek RW, Fix JD (2004). "Eye" (chapter 9). Embryology - Board Review Series (3rd edition, illustrated). Lippincott Williams & Wilkins. p. 92. ISBN 0-7817-5726-6, ISBN 978-0-7817-5726-3. Books.Google.com. Retrieved on 2010-01-17 from https://books.google.com/books?id=MmoJQWsJteoC.
Jump up ^ Moore KL, Dalley AF (2006). "Head (chapter 7)". Clinically Oriented Anatomy (5th ed.). Lippincott Williams & Wilkins. p. 972. ISBN 0-7817-3639-0.
Jump up ^ McDougal, David H.; Gamlin, Paul D. (January 2015). "Autonomic control of the eye". Comprehensive Physiology. 5 (1): 439–473. doi:10.1002/cphy.c140014. ISSN 2040-4603. PMC 4919817  . PMID 25589275.
Jump up ^ Brunton, L. L.; Chabner, Bruce; Knollmann, Björn C., eds. (2011). Goodman & Gilman's The Pharmacological Basis of Therapeutics (12 ed.). New York: McGraw-Hill. ISBN 978-0-07-162442-8.
Jump up ^ "Ocular Embryology with Special Reference to Chamber Angle Development". The Glaucomas. 2009. pp. 61–9. doi:10.1007/978-3-540-69146-4_8. ISBN 978-3-540-69144-0.
Jump up ^ Riordan-Eva Paul, "Chapter 1. Anatomy & Embryology of the Eye" (Chapter). Riordan-Eva P, Whitcher JP (2008). Vaughan & Asbury's General Ophthalmology (17th ed.). McGraw-Hill. AccessMedicine.com Archived 2009-07-06 at the Wayback Machine.
Jump up ^ Brunton, Laurence L.; Lazo, John S.; Parker, Keith, eds. (2005). Goodman & Gilman's The Pharmacological Basis of Therapeutics (11th ed.). New York: McGraw-Hill. pp. 134–135. ISBN 978-0-07-162442-8.
Jump up ^ Salmon John F, "Chapter 11. Glaucoma" (Chapter). Riordan-Eva P, Whitcher JP (2008). Vaughan & Asbury's General Ophthalmology (17th ed.). McGraw-Hill. AccessMedicine.com Archived 2009-07-06 at the Wayback Machine.
Jump up ^ Le, Tao T.; Cai, Xumei; Waples-Trefil, Flora. "QID: 22067". USMLERx. MedIQ Learning, LLC. 2006–2010. 13 January 2010 Usmlerx.com
Jump up ^ "cilia", Unabridged. Source location: Random House, Inc. Reference.com. Retrieved on 2010-01-16 from http://dictionary.reference.com/browse/cilia.
Jump up ^ Dictionary.com, "-ary", in The American Heritage Dictionary of the English Language, Fourth Edition. Source location: Houghton Mifflin Company, 2004. Reference.com. Retrieved on 2010-01-16 from http://dictionary.reference.com/browse/-ary.
Jump up ^ "ciliary," in Dictionary.com Unabridged. Source location: Random House, Inc. Reference.com. Retrieved on 2010-01-16 from http://dictionary.reference.com/browse/ciliary.
Bibliography[edit]
This section is empty. You can help by adding to it. (February 2017)
External links[edit]
Lens, zonule fibers, and ciliary muscles—SEM
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Decision tree
From Wikipedia, the free encyclopedia
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This article is about decision trees in decision analysis. For the use of the term in machine learning, see Decision tree learning.
This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (October 2013) (Learn how and when to remove this template message)
Traditionally, decision trees have been created manually.
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A decision tree is a decision support tool that uses a tree-like graph or model of decisions and their possible consequences, including chance event outcomes, resource costs, and utility. It is one way to display an algorithm that only contains conditional control statements.
Decision trees are commonly used in operations research, specifically in decision analysis, to help identify a strategy most likely to reach a goal, but are also a popular tool in machine learning.
Contents
[hide]
1 Overview
2 Decision tree building blocks
2.1 Decision tree elements
2.2 Decision rules
2.3 Decision tree using flowchart symbols
2.4 Analysis example
2.5 Influence diagram
3 Association rule induction
4 Advantages and disadvantages
5 See also
6 References
7 External links
Overview[edit]
A decision tree is a flowchart-like structure in which each internal node represents a "test" on an attribute (e.g. whether a coin flip comes up heads or tails), each branch represents the outcome of the test, and each leaf node represents a class label (decision taken after computing all attributes). The paths from root to leaf represent classification rules.
In decision analysis, a decision tree and the closely related influence diagram are used as a visual and analytical decision support tool, where the expected values (or expected utility) of competing alternatives are calculated.
A decision tree consists of three types of nodes:[1]
Decision nodes – typically represented by squares
Chance nodes – typically represented by circles
End nodes – typically represented by triangles
Decision trees are commonly used in operations research and operations management. If, in practice, decisions have to be taken online with no recall under incomplete knowledge, a decision tree should be paralleled by a probability model as a best choice model or online selection model algorithm. Another use of decision trees is as a descriptive means for calculating conditional probabilities.
Decision trees, influence diagrams, utility functions, and other decision analysis tools and methods are taught to undergraduate students in schools of business, health economics, and public health, and are examples of operations research or management science methods.
Decision tree building blocks[edit]
Decision tree elements[edit]
Drawn from left to right, a decision tree has only burst nodes (splitting paths) but no sink nodes (converging paths). Therefore, used manually, they can grow very big and are then often hard to draw fully by hand. Traditionally, decision trees have been created manually — as the aside example shows — although increasingly, specialized software is employed.
Decision rules[edit]
The decision tree can be linearized into decision rules,[2] where the outcome is the contents of the leaf node, and the conditions along the path form a conjunction in the if clause. In general, the rules have the form:
if condition1 and condition2 and condition3 then outcome.
Decision rules can be generated by constructing association rules with the target variable on the right. They can also denote temporal or causal relations.[3]
Decision tree using flowchart symbols[edit]
Commonly a decision tree is drawn using flowchart symbols as it is easier for many to read and understand.
Analysis example[edit]
Analysis can take into account the decision maker's (e.g., the company's) preference or utility function, for example:
The basic interpretation in this situation is that the company prefers B's risk and payoffs under realistic risk preference coefficients (greater than $400K—in that range of risk aversion, the company would need to model a third strategy, "Neither A nor B").
Influence diagram[edit]
Much of the information in a decision tree can be represented more compactly as an influence diagram, focusing attention on the issues and relationships between events.
The rectangle on the left represents a decision, the ovals represent actions, and the diamond represents results.
Association rule induction[edit]
Decision trees can also be seen as generative models of induction rules from empirical data. An optimal decision tree is then defined as a tree that accounts for most of the data, while minimizing the number of levels (or "questions").[4] Several algorithms to generate such optimal trees have been devised, such as ID3/4/5,[5] CLS, ASSISTANT, and CART.
Advantages and disadvantages[edit]
Among decision support tools, decision trees (and influence diagrams) have several advantages. Decision trees:
Are simple to understand and interpret. People are able to understand decision tree models after a brief explanation.
Have value even with little hard data. Important insights can be generated based on experts describing a situation (its alternatives, probabilities, and costs) and their preferences for outcomes.
Allow the addition of new possible scenarios.
Help determine worst, best and expected values for different scenarios.
Use a white box model. If a given result is provided by a model.
Can be combined with other decision techniques.
Disadvantages of decision trees:
They are unstable, meaning that a small change in the data can lead to a large change in the structure of the optimal decision tree.
They are often relatively inaccurate. Many other predictors perform better with similar data. This can be remedied by replacing a single decision tree with a random forest of decision trees, but a random forest is not as easy to interpret as a single decision tree.
For data including categorical variables with different number of levels, information gain in decision trees is biased in favor of those attributes with more levels.[6]
Calculations can get very complex, particularly if many values are uncertain and/or if many outcomes are linked.
See also[edit]
Behavior tree (artificial intelligence, robotics and control)
Boosting (machine learning)
Decision cycle
Decision list
Decision table
Decision tree model of computation
Design rationale
DRAKON
Markov chain
Random forest
Odds algorithm
Topological combinatorics
Truth table
References[edit]
Jump up ^ Kamiński, B.; Jakubczyk, M.; Szufel, P. (2017). "A framework for sensitivity analysis of decision trees". Central European Journal of Operations Research. doi:10.1007/s10100-017-0479-6.
Jump up ^ Quinlan, J. R. (1987). "Simplifying decision trees". International Journal of Man-Machine Studies. 27 (3): 221. doi:10.1016/S0020-7373(87)80053-6.
Jump up ^ K. Karimi and H.J. Hamilton (2011), "Generation and Interpretation of Temporal Decision Rules", International Journal of Computer Information Systems and Industrial Management Applications, Volume 3
Jump up ^ R. Quinlan, "Learning efficient classification procedures", Machine Learning: an artificial intelligence approach, Michalski, Carbonell & Mitchell (eds.), Morgan Kaufmann, 1983, p. 463-482. doi:10.1007/978-3-662-12405-5_15
Jump up ^ Utgoff, P. E. (1989). Incremental induction of decision trees. Machine learning, 4(2), 161-186. doi:10.1023/A:1022699900025
Jump up ^ Deng,H.; Runger, G.; Tuv, E. (2011). Bias of importance measures for multi-valued attributes and solutions. Proceedings of the 21st International Conference on Artificial Neural Networks (ICANN).
External links[edit]
Wikimedia Commons has media related to decision diagrams.
Extensive Decision Tree tutorials and examples
Gallery of example decision trees
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