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In the context of hardware and software systems, formal verification is the act of proving or disproving the correctness of intended algorithms underlying a system with respect to a certain formal specification or property, using formal methods of mathematics^{[citation needed]}.

Usage[link]

Formal verification can be helpful in proving the correctness of systems such as: cryptographic protocols, combinational circuits, digital circuits with internal memory, and software expressed as source code.

The verification of these systems is done by providing a formal proof on an abstract mathematical model of the system, the correspondence between the mathematical model and the nature of the system being otherwise known by construction. Examples of mathematical objects often used to model systems are: finite state machines, labelled transition systems, Petri nets, timed automata, hybrid automata, process algebra, formal semantics of programming languages such as operational semantics, denotational semantics, axiomatic semantics and Hoare logic.^{[citation needed]}

Approaches to formal verification[link]

One approach and formation is model checking, which consists of a systematically exhaustive exploration of the mathematical model (this is possible for finite models, but also for some infinite models where infinite sets of states can be effectively represented finitely using abstraction). Usually this consists of exploring all states and transitions in the model, by using smart and domain-specific abstraction techniques to consider whole groups of states in a single operation and reduce computing time. Implementation techniques include state space enumeration, symbolic state space enumeration, abstract interpretation, symbolic simulation, abstraction refinement. The properties to be verified are often described in temporal logics, such as linear temporal logic (LTL) or computational tree logic (CTL).

Another approach is logical inference. It consists of using a formal version of mathematical reasoning about the system, usually using theorem proving software such as a HOL theorem prover, the ACL2, Isabelle, or Coq theorem provers. This is usually only partially automated and is driven by the user's understanding of the system to validate. Recent tools such as Perfect Developer and Escher C Verifier attempt to automate the proof process fully.

"Non-classical" logics such as linear logic and temporal logics can also be used in logical inference, not just in model checking.

Formal verification for software[link]

Logical inference for the formal verification of software can be further divided into:

• the more traditional 1970s approach in which code is first written in the usual way, and subsequently proven correct in a separate step;
• dependently typed programming, in which the types of functions include (at least part of) those functions' specifications, and type-checking the code establishes its correctness against those specifications. Fully featured dependently typed languages support the first approach as a special case.

A slightly different (and complementary) approach is program derivation, in which efficient code is produced from functional specifications by a series of correctness-preserving steps. An example of this approach is the Bird-Meertens Formalism, and this approach can be seen as another form of correctness by construction.

Verification and validation[link]

Verification is one aspect of testing a product's fitness for purpose. Validation is the complementary aspect. Often one refers to the overall checking process as V & V.

• Validation: "Are we trying to make the right thing?", i.e., is the product specified to the user's actual needs?
• Verification: "Have we made what we were trying to make?", i.e., does the product conform to the specifications?

The verification process consists of static/structural and dynamic/behavioral aspects. E.g., for a software product one can inspect the source code (static) and run against specific test cases (dynamic). Validation usually can be done only dynamically, i.e., the product is tested by putting it through typical and atypical usages ("Does it satisfactorily meet all use cases?").

Industry use[link]

The growth in complexity of designs increases the importance of formal verification techniques in the hardware industry.^[2][3] At present, formal verification is used by most or all^{[citation needed]} leading hardware companies, but its use in the software industry is still languishing.^{[citation needed]} This could be attributed to the greater need in the hardware industry, where errors have greater commercial significance.^{[citation needed]} Because of the potential subtle interactions between components, it is increasingly difficult to exercise a realistic set of possibilities by simulation. Important aspects of hardware design are amenable to automated proof methods, making formal verification easier to introduce and more productive.^[4]

As of 2011^[update], several operating systems have been formally verified: NICTA's Secure Embedded L4 microkernel, sold commercially as seL4 by OK Labs;^{[citation needed]} OSEK/VDX based real-time operating system ORIENTAIS by East China Normal University;^{[citation needed]} Green Hills Software's Integrity operating system;^{[citation needed]} and SYSGO's PikeOS.^[5][6]

See also[link]

Software Testing portal

Look up verifiability in Wiktionary, the free dictionary.

• Automated theorem proving
• Formal equivalence checking
• LURCH
• Proof checker
• Property Specification Language
• Selected formal verification bibliography
• Static code analysis
• Temporal logic in finite-state verification
• Post silicon validation
• Intelligent verification
• Runtime verification

References[link]

Rachel Maddow
Maddow hosting KPTK's "Changing the Media, Changing America" event in Seattle
Born	Rachel Anne Maddow (1973-04-01) April 1, 1973 (age 39) Castro Valley, California, U.S.
Education	B.A., Stanford University D.Phil, University of Oxford
Occupation	News anchor Political commentator Television host
Notable credit(s)	The Rachel Maddow Show (MSNBC) The Rachel Maddow Show (Air America Radio)
Website
www.rachelmaddow.com

Rachel Anne Maddow (pronounced /ˈmædoʊ/; born April 1, 1973) is an American television host, political commentator, and author.^[1][2] Maddow hosts a nightly television show, The Rachel Maddow Show, on MSNBC.^[3] Her syndicated talk radio program of the same name aired on Air America Radio. Maddow is the first openly gay anchor of a prime-time news program in the United States.^[4][5][6][7]

Asked about her political views by the Valley Advocate, Maddow replied, "I'm undoubtedly a liberal, which means that I'm in almost total agreement with the Eisenhower-era Republican party platform."^[8]

Early life and education[link]

Maddow was born in Castro Valley, California. Her father, Robert B. "Bob" Maddow, is a former United States Air Force captain who resigned his commission the year before her birth and found civilian work as a lawyer for the East Bay Municipal Utility District. Her mother, Elaine Maddow (née Gosse), is a school program administrator from Newfoundland, Canada.^[9][10][11] She has one older brother, David. Her father is of Russian and Dutch descent and her mother is of English and Irish ancestry.^[11] Maddow's mother was raised a strict Roman Catholic, and Maddow herself grew up in a community that her mother has described as "very conservative."^[12][13] Maddow was a competitive athlete and played three sports in high school.^[14] Referencing John Hughes films, she describes herself in high school as "a cross between the jock and the antisocial girl."^[13]

A graduate of Castro Valley High School in Castro Valley, California, she attended Stanford University. While a freshman, she was outed by the college newspaper when an interview with her was published by the student newspaper before she could tell her parents.^[15] Maddow earned a degree in public policy from Stanford in 1994.^[16] At graduation she was awarded the John Gardner Fellowship.^[17] She was also the recipient of a Rhodes Scholarship and began her postgraduate study in 1995 at Lincoln College, Oxford. In 2001, she earned a Doctor of Philosophy (DPhil) in politics from Oxford University.^[18] Her thesis is titled HIV/AIDS and Health Care Reform in British and American Prisons (supervisor: Dr Lucia Zedner). She was the first openly gay American to win a Rhodes scholarship.^[19][20]

Radio career[link]

Maddow's first radio hosting job was at WRNX (100.9 FM) in Holyoke, Massachusetts, after she entered and won a contest the station held to find a new on-air personality.^[21] She was hired to co-host WRNX's morning show, The Dave in the Morning Show. She went on to host Big Breakfast on WRSI, in Northampton, Massachusetts, for two years. She left the show in March 2004 to join the new Air America.^[18] There she hosted Unfiltered along with Chuck D (of the hip hop group Public Enemy) and Lizz Winstead (co-creator of The Daily Show), until its cancellation in March 2005.^[22] Two weeks after the cancellation of Unfiltered in April 2005, Maddow's weekday two-hour radio program, The Rachel Maddow Show, began airing; in March 2008 it gained an hour, broadcasting from 6 to 9 p.m. EST with David Bender filling in the third hour for the call-in section, when Maddow was on TV assignment. In September 2008, the show's length returned to two hours when Maddow began a nightly MSNBC television program. In February 2009, after renewing her contract with Air America, Maddow returned to the 5 am hour-long slot.^[23] Her last Air America show was on January 21, 2010, two weeks before its owners filed for bankruptcy.^[24]

Television career[link]

In June 2005, Maddow became a regular panelist on MSNBC's Tucker.^[25] During and after the November 2006 election, she was a frequent guest on CNN's Paula Zahn Now. In January 2008, Maddow became a MSNBC political analyst and was a regular panelist on MSNBC's Race for the White House with David Gregory and MSNBC's election coverage,^[26] as well as a frequent contributor on Countdown with Keith Olbermann.^[18]

In April 2008, Maddow was the substitute host for Countdown with Keith Olbermann, her first time hosting a program on MSNBC. Maddow described herself on air as "nervous." Keith Olbermann complimented her work, and she was brought back to host Countdown the next month. The show she hosted was the highest rated news program among people ages 25 to 54, a key demographic in ratings.^[27] For her success, the next Monday, Olbermann ranked Maddow third in his show's segment "World's Best Persons".^[28] In July 2008, while Olbermann was on vacation, Maddow filled in again for several broadcasts and, on July 21, for half the show.^[29] Maddow also filled in for David Gregory as host of Race for the White House.^[18]

[edit] The Rachel Maddow Show

In August 2008, MSNBC announced The Rachel Maddow Show would replace Verdict with Dan Abrams in the network's 9 p.m. slot the following month.^[30][31] Following its debut, the show topped Countdown as the highest rated show on MSNBC on several occasions.^[32][33] After being on air for more than a month, Maddow's program doubled the audience that hour.^[34]

Early reviews for her show were mostly positive. The Los Angeles Times writer Matea Gold stated Maddow "finds the right formula on MSNBC,"^[35] and The Guardian writes Maddow has become the "star of America's cable news."^[20] Associated Press columnist David Bauder said she's "[Keith] Olbermann's political soul mate" and the Olbermann-Maddow shows are a "liberal two-hour block."^[36]

Public image and publicity[link]

Maddow has been profiled in People,^[37] the Guardian,^[38] and the New York Observer,^[39] has appeared on “The View” and “Charlie Rose”^[40]

Keith Olbermann played a pivotal role in Maddow's hiring at MSNBC. Olbermann was able to pressure Phil Griffin to give Maddow Dan Abram's slot. A fan of Maddow's, Olbermann was able to use his influence, which had become greater as his ratings rose.^[41]

A 2011 Hollywood Reporter profile of Maddow said that she was able to deliver news "with agenda, but not hysteria.”^[42] A Newsweek profile noted that “At her best, Maddow debates ideological opponents with civility and persistence...But for all her eloquence, she can get so wound up ripping Republicans that she sounds like another smug cable partisan.". Baltimore Sun critic David Zurawik has accused Maddow of acting like 'a lockstep party member.'”^[43]

A Time profile called her a “whip-smart, button-cute leftie.” It said that she radiates an essential decency and suggested that her career rise might signify that “nice is the new nasty.”^[44]

Political views[link]

Distinguishing herself from others on the left, Maddow said she's a "national security liberal" and in a different interview that she's not "a partisan."^[45][46] The New York Times called her a "defense policy wonk" who is writing a book on the role of the military in postwar American politics.^[35][45] (The book, titled Drift: The Unmooring of American Military Power, was published in 2012.) During the 2008 presidential election, Maddow did not formally support any candidate. Concerning Barack Obama's candidacy, Maddow said during the primaries, "I have never and still don't think of myself as an Obama supporter, either professionally or actually."^[47]

In March 2010, Republican Scott Brown, the junior United States Senator from Massachusetts, speculated that Maddow was going to run against him for his seat in 2012. He used this premise for a fundraising email that read "...The Massachusetts political machine is looking for someone to run against me. And you're not going to believe who they are supposedly trying to recruit — liberal MSNBC anchor Rachel Maddow." Maddow said Brown's speculation was false. On her March 23, 2010, TV program, Maddow said, "I have the best job in the world. I am not running for office. Scott Brown didn't ask me if I was running or planning to run for office, before he wrote a fundraising letter with my name. No, it's completely made up by him." Despite her comments, the next day Brown continued along the same line, telling a Boston radio station, "Bring her on." To help put an end to the matter, Maddow ran a full-page advertisement in the Boston Globe confirming she was not running, and separately demanded Brown's apology. She added that despite repeated invitations over the months, Brown had refused to appear on her TV program.^{[48][49][50][51]}

Personal life[link]

Maddow lives in Manhattan and western Massachusetts with her partner, artist Susan Mikula.^[52][53] The couple met in 1999, when Mikula hired Maddow to do yard work at her home. Maddow was working on her doctoral dissertation at the time.^[52] Their first date was at a National Rifle Association "Ladies' Day on the Range" event.^[54] Although Massachusetts and New York recognize same-sex marriage, as of 2009 Maddow and Mikula had no plans to marry.^[13]

Honors and awards[link]

• Emmy Award in the Outstanding News Discussion and Analysis category for "The Rachel Maddow Show" episode "Good Morning Landlocked Central Asia!"
• Maddow was named in Out magazine's "Out 100" list of the "gay men and women who moved culture" in 2008.^[55]
• Maddow was voted "Lesbian/Bi Woman of the Year (American)" in AfterEllen's 2008 Visibility Awards.^[56]
• Maddow won a Gracie Award in 2009, presented by the American Women in Radio and Television.^[57]
• In 2009, Maddow was nominated for GLAAD's 20th Annual Media Awards for a segment of her MSNBC show, "Rick Warren, Change To Believe In?", in the Outstanding TV Journalism Segment category.^[58]
• On March 28, 2009, Maddow received a Proclamation of Honor from the California State Senate, presented in San Francisco by California State Senator Mark Leno.^[59]
• In April 2009, she was listed at number four in Out magazine's Annual Power 50 List.^[60]
• Maddow placed sixth in the "2009 AfterEllen.com Hot 100" list (May 11, 2009)^[61] and third in its "2009 Hot 100: Out Women" version.^[62]
• Maddow was included on a list of openly gay media professionals in The Advocate's "Forty under 40" issue of June/July 2009.^[63]
• In 1994, Maddow was an Honorable Mention in the Elie Wiesel Foundation for Humanity Prize in Ethics.^[64]
• In June 2009, Maddow's MSNBC show was the only cable news show nominated for a Television Critics Association award in the Outstanding Achievement in News and Information category.^[65]
• In March 2010, Maddow won at the 21st Annual GLAAD Media Awards in the category, Outstanding TV Journalism- Newsmagazine for her segment, "Uganda Be Kidding Me".^[66]
• Maddow was the 2010 commencement speaker and was given an honorary Doctor of Laws (LLD) degree at Smith College in Northampton, MA in May 2010.^[67]
• In July 2010, Maddow was presented with a Maggie Award for her ongoing reporting of healthcare reform, the murder of Dr. George Tiller, and the anti-abortion movement.^[68]
• In August 2010, Maddow won the Walter Cronkite Faith & Freedom Award, which was presented by The Interfaith Alliance.^[69] Past honorees included Larry King, Tom Brokaw, and the late Peter Jennings.^[69]
• In November 2011, she was included on the list of "Over-Rated Thinkers" by the editors of The New Republic.^[70]
• In February 2012, Maddow was presented the John Steinbeck Award by the Martha Heasley Cox Center for Steinbeck Studies at San Jose State University.^[71]

Bibliography[link]

• Maddow, Rachel (2012). Drift: The Unmooring of American Military Power. Crown. ISBN 978-0-307-46098-1. 

References[link]

External links[link]

Wikimedia Commons has media related to: Rachel Maddow

• Rachel Maddow on Twitter
• Official website
• Profile and show at MSNBC
• Appearances on C-SPAN
• Rachel Maddow on Charlie Rose
• Rachel Maddow at the Internet Movie Database
• Works by or about Rachel Maddow in libraries (WorldCat catalog)