Electrical impedance is the measure of the opposition that a circuit presents to a current when a voltage is applied. The term complex impedance may be used interchangeably. Quantitatively, the impedance of a two-terminal circuit element is the ratio of the complex representation of a sinusoidal voltage between its terminals to the complex representation of the current flowing through it. In general, it depends upon the frequency of the sinusoidal voltage. Impedance extends the concept of resistance to AC circuits, possesses both magnitude and phase, unlike resistance, which has only magnitude; when a circuit is driven with direct current, there is no distinction between impedance and resistance. The notion of impedance is useful for performing AC analysis of electrical networks, because it allows relating sinusoidal voltages and currents by a simple linear law. In multiple port networks, the two-terminal definition of impedance is inadequate, but the complex voltages at the ports and the currents flowing through them are still linearly related by the impedance matrix.

Impedance is a complex number, with the same units as resistance. Its symbol is Z, it may be represented by writing its magnitude and phase in the form |Z|∠θ. However, cartesian complex number representation is more powerful for circuit analysis purposes; the reciprocal of impedance is admittance, whose SI unit is the siemens called mho. Instruments used to measure the electrical impedance are called impedance analyzers; the term impedance was coined by Oliver Heaviside in July 1886. Arthur Kennelly was the first to represent impedance with complex numbers in 1893. In addition to resistance as seen in DC circuits, impedance in AC circuits includes the effects of the induction of voltages in conductors by the magnetic fields, the electrostatic storage of charge induced by voltages between conductors; the impedance caused by these two effects is collectively referred to as reactance and forms the imaginary part of complex impedance whereas resistance forms the real part. Impedance is defined as the frequency domain ratio of the voltage to the current.

In other words, it is the voltage–current ratio for a single complex exponential at a particular frequency ω. For a sinusoidal current or voltage input, the polar form of the complex impedance relates the amplitude and phase of the voltage and current. In particular: The magnitude of the complex impedance is the ratio of the voltage amplitude to the current amplitude; the impedance of a two-terminal circuit element is represented as a complex quantity Z. The polar form conveniently captures both magnitude and phase characteristics as Z = | Z | e j arg ⁡ where the magnitude | Z | represents the ratio of the voltage difference amplitude to the current amplitude, while the argument arg ⁡ gives the phase difference between voltage and current. J is the imaginary unit, is used instead of i in this context to avoid confusion with the symbol for electric current. In Cartesian form, impedance is defined as Z = R + j X where the real part of impedance is the resistance R and the imaginary part is the reactance X.

Where it is needed to add or subtract impedances, the cartesian form is more convenient. A circuit calculation, such as finding the total impedance of two impedances in parallel, may require conversion between forms several times during the calculation. Conversion between the forms follows the normal conversion rules of complex numbers. To simplify calculations, sinusoidal voltage and current waves are represented as complex-valued functions of time denoted as V and I. V = | V | e j; the impedance of a bipolar circuit is defined as the ratio of these quantities: Z = V I = | V | | I | e j ( ϕ V − ϕ

Ulyanovsk is a city and the administrative center of Ulyanovsk Oblast, located on the Volga River 705 kilometers east of Moscow. Population: 613,786 ; the city, founded as Simbirsk, is the birthplace of Alexander Kerensky and Vladimir Lenin, for whom it was renamed in 1924. It is famous for its writers such as Ivan Goncharov, Nikolay Yazykov and Nikolay Karamzin and painters. Ulyanovsk – UNESCO City of Literature since 2015. Simbirsk was founded in 1648 by the boyar Bogdan Khitrovo; the fort of "Simbirsk" was strategically placed on a hill on the Western bank of the Volga River. The fort was meant to protect the eastern frontier of the Russian Empire from the nomadic tribes and to establish a permanent Imperial presence in the area. In 1668, Simbirsk withstood a month-long siege by a 20,000-strong army led by rebel Cossack commander Stenka Razin. In Simbirsk another country rebel, Yemelyan Pugachev, was imprisoned before execution. At the time Simbirsk possessed a wooden kremlin, destroyed by a fire during the 18th century.

As the eastern border of the Russian Empire was pushed into Siberia, Simbirsk lost its strategic importance, but nonetheless began to develop into an important regional center. Simbirsk was granted city status in 1796. In the summer of 1864, Simbirsk was damaged by fire; the Holy Trinity Cathedral was constructed in a restrained Neoclassical style between 1827 and 1841. The population of Simbirsk reached 26,000 by 1856 and 43,000 by 1897. In 1924, the city was renamed Ulyanovsk in honor of Vladimir Ulyanov, better known as Lenin, born in Simbirsk in 1870. Two other Russian political leaders, Alexander Kerensky and Alexander Protopopov, were born in Simbirsk; the construction of the Kuybyshev hydroelectric plant 200 kilometers downstream of Ulyanovsk resulted in the flooding of significant tracts of land both north and south of Ulyanovsk and increasing the width of the Volga by up to 35 kilometers in some places. To this day, some populated neighborhoods of Ulyanovsk remain well below the level of the reservoir, protected from flooding by a dam: it is estimated that its catastrophic failure would submerge parts of the city comprising around 5% of its total population with as much as 10 meters of water.

During the Soviet period, Ulyanovsk was an important tourist center, drawing visitors from around the country because of its revolutionary importance. After the dissolution of the Soviet Union, the tourist importance of Ulyanovsk decreased. In the 1990s, the city went through the hardest times—a slump in production in all branches, mass unemployment, a population impoverishment. Besides the policy of the regional authorities of that time leaning against the grants and the Soviet system of managing, has led to serious crisis of a city infrastructure. In the first decade of the 2000s the economy started to grow. Ulyanovsk recovered from these downturns into regional manufacturing and transportation clusters; the city is headed by a mayor, the executive branch, city council, the legislative branch. The term of the mayor is five years. In 2010 the city council abolished the direct elections to the mayor, replacing it with city manager, appointed by the council. Again, in April 2013 the city charter was amended to re-introduce the direct mayoral election.

Ulyanovsk serves as the administrative center of the oblast. Within the framework of administrative divisions, it is, together with thirty rural localities, incorporated as the city of oblast significance of Ulyanovsk—an administrative unit with the status equal to that of the districts; as a municipal division, the city of oblast significance of Ulyanovsk is incorporated as Ulyanovsk Urban Okrug. In 2008, there were registered 8,054 deaths in Ulyanovsk. Russians: 78% Tatars: 10% Chuvash: 6% Mordvins: 2% Germans: 1% Ulyanovsk has a humid continental climate. Average temperature is − +20.2 °C in July. Falls are warm, with snow beginning to accumulate by mid-November. Winters tend to be cold but with moderate amounts of snowfall and nighttime lows dipping below −25 °C. Summer weather arrives in mid-May. Precipitation averages about 470 millimeters; the city is subject to frequent, but moderate, droughts. Springs and summers are sunny, but fall and winter are cloudy. Median annual temperature is +4.9 °C.

Ulyanovsk is a major, industrial hub for aircraft and auto industries. The UAZ automobile manufacturing plant. An international airline for unique and heavy cargo, Volga-Dnepr Airlines, is based in the city. There are many manufacturing facilities of foreign corporations such as Legrand, Incorporated, Takata-Petri, Anadolu Efes S. K.. ALFA and others. Banking is represented by national banks such as Sberbank, VTB Bank, Alfa-Bank, Bin Bank, Ak Bars Bank, MDM Bank, Trust Bank and r

Walter Galenson was a professor of economics at Cornell University and a noted U. S. labor historian and economist. He received his bachelor's degree in 1934, his Master of Science in 1935 and his Ph. D. in 1940—all from Columbia University. During World War II, Galenson was an economist United States Department of War, he was the principal economist for the department from 1942 to 1943. He became principal economist at the Office of Strategic Services from 1943 to 1944. After the war, Galenson was a labor attaché at the American embassies in Norway and Denmark from 1945 to 1946. Galenson received an appointment as an assistant professor of economics at Harvard University in 1946, he left Harvard in 1951 to teach economics at the University of California, where, from 1957 to 1961, he was chair of the Center for Chinese Studies. He left Berkeley in 1965, one of many prominent academics who left after being accused of being too conservative, took a position as a visiting professor of economics at Cornell University.

Galenson became active in labor and Third World economic development issues, from 1961 to 1971, he served as a consultant to the International Labour Organization. He served as the U. S. delegate to the ILO in 1972 and again in 1976. In 1966, Galenson joined the faculty at Cornell permanently as a professor of economics. In 1970, Galenson spent an academic year as Pitt Professor of American History and Institutions at Cambridge University in the United Kingdom, he was the first non-historian to hold the post. While teaching at Cambridge, he was awarded a second master's degree in 1971. From 1971 to 1972, Galenson served as a consultant in economic development to the government of Indonesia. In 1974, Galenson was appointed a visiting professor of economics at University of Gothenburg, Sweden, he married, he and his wife Marjorie had a son, David Galenson, two daughters. Galenson retired from teaching in 1990, died in his sleep on December 30, 1999, in Washington, D. C. Galenson's research focused on labor history, comparative labor studies, labor economics, the economics of development in emerging markets.

Galenson's primary reputation was based on his work in comparative labor economics. He made the first serious study by a Westerner of labor productivity in the Soviet Union. In the late 1950s and early 1960s, he directed a large research project, financed by the Ford Foundation, on the economic development of the Chinese economy—one of the first studies of the modernization of the Chinese economy and its effect on surrounding nations, his 1964 book, The Quality of Labour and Economic Development in Certain Countries: A Preliminary Study, was a pioneering study of how the living conditions of people in the Third World affected economic development in industrialized nations. Galenson was internationally recognized as an expert on trade unionism and economics in Scandinavia. However, Galenson's work as a labor historian was significant, his 1960 book, The CIO Challenge to the AFL: A History of the American Labor Movement, is still cited as one of the fundamental works in the field. Galenson promoted the view that the Taft-Hartley Act and the anti-communism of the 1950s sundered the coalition labor had with political leftists, contributed to the decline of the labor movement.

The view, controversial at the time, is adopted today. Galenson is one of the few labor historians to study the history of the American labor movement in the post-AFL-CIO merger era, his 1996 work, The American Labor Movement, 1955–1995, covers the AFL-CIO's efforts in the 1960s, 1970s, 1980s—a neglected period of labor history. His 1981 study of the U. S. policy toward the International Labour Organization remains the most valuable work on that topic. In 1950, Galenson was named a Fulbright fellow. In 1954, he was awarded a Guggenheim Fellowship in economics. Galenson was a member of the American Philological Association, he was a member of the Association for Comparative Economic Studies, served as that organization's president in 1973. The American Labor Movement, 1955–1995. Westport, Conn.: Greenwood Press, 1996. ISBN 0-313-29677-4 The CIO Challenge to the AFL: A History of the American Labor Movement. Cambridge, Massachusetts: Harvard University Press, 1960. ISBN 0-674-13150-9 The Danish System of Labor Relations: A Study in Industrial Peace.

Cambridge, Massachusetts: Harvard University Press, 1952. The International Labor Organization: An American View. 1st ed. Madison, Wisc.: University of Wisconsin Press, 1981. ISBN 0-299-08544-9 Labor in Norway. New York City: Russell & Russell, 1949; the Quality of Labour and Economic Development in Certain Countries: A Preliminary Study. Geneva, Switzerland: International Labour Office, 1964. Trade Union Democracy in Western Europe. Berkeley, Calif.: University of California Press, 1961. Trade Union Growth and Decline: An International Study. 1st ed. Westport, Conn.: Praeger Publishers, 1994. ISBN 0-275-94325-9 The United Brotherhood of Carpenters: The First Hundred Years. 1st ed. Cambridge, Massachusetts" Harvard University Press, 1983. ISBN 0-674-92196-8 The World's Strongest Trade Unions: The Scandinavian Labor Movement. Westport, Conn.: Greenwood Press, 1998. ISBN 1-56720-183-0 Adams, John Clarke and Galenson, Walter. Comparative Labor Movements. New York City: Prentice Hall, 1952. Galenson and Lipset, Seymour Martin.

Labor and Trade Unionism: An Interdisciplinary Reader. New York City: John Wiley & Sons, Inc. 1960. Comparative Labor Movements. Galenson, Walter, ed. 2nd ed. New York City: Russell & Russell Publishers, 1968. ISBN 0-8462-1064-9 Foreign Trade and Investment. Economic Development in

Hazen Kimball was an American merchant and politician who served as the tenth Mayor of Hoboken, New Jersey from 1869 to 1871. Kimball was vice president of the First National Bank of Hoboken and president of the Gansevoort Bank of New York, he was born on February 1835 in Barton, Vermont. He served as the tenth Mayor of Hoboken, New Jersey from 1869 to 1871. Prior to the 1869 vote concerning consolidation with Jersey City, Kimball asserted the health of his city: "Hoboken keeps pace at least, if it does not goes beyond, our sister cities in rapid increase of population and wealth." Unlike Bergen City and Hudson City, Hoboken chose to remain independent. He was vice president of the First National Bank of Hoboken and president of the Gansevoort Bank of New York, he died on June 22, 1890 of apoplexy in Hoboken, New Jersey

Petra Elisabeth Todd is an American economist whose research interests include labor economics, development economics and econometrics. She is the Edward J. and Louise W. Kahn Term Professor of Economics at the University of Pennsylvania, is affiliated with the University of Pennsylvania Population Studies Center, the Human Capital and Equal Opportunity Global Working Group, the IZA Institute of Labor Economics and the National Bureau of Economic Research. Petra Todd graduated from the University of Virginia in 1989 with a double major in economics and English, she did her graduate studies in economics at the University of Chicago, completing her Ph. D. in 1996. Her dissertation, Three Essays on Empirical Methods for Evaluating the Impact of Policy Interventions in Education and Training, was jointly supervised by James Heckman, Hidehiko Ichimura, Derek Allen Neal, she has been a faculty member at the University of Pennsylvania since 1996. She was promoted to Associate Professor with tenure in 2002 and to Full Professor in 2006.

She held the named chair of Alfred L. Cass Term Chair Professor of Economics from 2010 to 2016, was given the Kahn Professorship in 2017. Todd is a fellow of the Econometric Society, the Society of Labor Economists, the International Association for Applied Econometrics. Petra Todd is an empirical economist with research contributions in the area of labor economics, economics of education, econometrics and demography, she is best known for her work on program evaluation methods, which develops methods for evaluating the effects of interventions in education and training using both experimental and nonexperimental data. She finished a book manuscript Impact Evaluation in Developing Countries: Theory and Practice, coauthored with Paul Glewwe, that will be published by the World Bank in 2020. One of Petra Todd's areas of expertise is matching methods; these statistics/econometric techniques are used to evaluate the impact of Active Labor Market programs, which are government programs that provide education and incentives for unemployed or out of labor force workers to gain employment.

In developing country settings, the methods are used to evaluate the effectiveness of anti-poverty programs, such as conditional cash transfer programs. In early work and coauthors proposed new nonparametric matching estimators that are now used. Petra Todd has written seminal papers on regression discontinuity methods. RD is a quasi-experimental design where there is a variable and a cut-off value that wholly or determines treatment assignment. For example, children whose pre-test score falls below a threshold may be assigned to an educational intervention. One of the earliest papers on the use of RD methods in economics is Hahn, Todd & Van der Klaauw, which develops new nonparametric estimators and shows that RD has an interpretation of a local average treatment effect in a heterogeneous treatment effects setting. Other topics in her work concerns reducing structural inequality in education in developing countries, through an educational policy that aims at improving the education of the least-well-served students.

In particular she has studied the effects of programs like that provide cash incentives for poor families to send their children to school. She was an expert consultant in designing the Mexican Progresa experiment that randomized 506 rural villages in or out of a conditional transfer program. Experimental evidence on the effectiveness of Progresa in increasing schooling and improving health was important to the adoption of similar anti-poverty programs in more than 60 countries around the world. Petra Todd played a key role in the design of the ALI experiment in Mexico that randomized 88 high schools to a student and teacher incentive program that paid for improvement on mathematics curriculum tests; the program impacts are analyzed in Behrman et al. and the data are used to study the determinants of educational performance in Todd and Wolpin. Todd has research on testing for racial profiling in the context of motor vehicle searches. Knowles, Persico & Todd observed that African-American motorists were more than three times as as other motorists to be stopped and searched by Maryland police, but had drugs found in the search with the same likelihood as other motorists.

Todd and her coauthors argued from this data that African-Americans had a higher propensity than others to carry drugs, that the greater number of stops were causing them to carry drugs less and that the equal rate of drugs found was evidence that the police were not being racist in their more frequent stops. Petra Todd has written chapters in the Handbook of Econometrics, Handbook of Development Economics, Handbook of Education Economics, Handbook of Labor Economics. In recent research, Petra Todd uses dynamic discrete choice structural modeling methods for predicting the impacts of programs that do not yet exist, useful at the stage of designing a new social program or in considering changes to an existing program. Another focus is on the empirical modeling of household behaviors, such as choices about fertility, schooling and savings. Todd some recent published papers that analyze the role of personality traits in educational and working decisions and in time allocation of husbands and wives.

Heckman, J. J.. E.. "M

Kristan Kennedy is an artist and educator in Portland, Oregon who has exhibited internationally. She works with various media including painting. Kennedy is the Visual Art curator at the Portland Institute for Contemporary Art in Portland, Oregon. Kennedy curates video, installation and new media projects for PICA's annual Time-Based Art Festival, she is the co-founder of the artist collective Swallow Press with artist Topher Sinkinson and their temporal public projects have been presented internationally. Her printed ephemera is held in several book collections, including the Museum of Modern Art, Dartmouth College and the New York Public Library. In April 2018, Kennedy was awarded the Bonnie Bronson Award, a prestigious regional award administered by Reed College that annually awards "a no-strings-attached cash prize to an artist of outstanding merit who lives and works in the Pacific Northwest." Kennedy received her BFA from the New York State College of Art and Design at Alfred University, Alfred NY, with a concentration on Printmaking and New Media in 1994.

Kennedy teaches Contemporary Art History at Portland State University, where she organizes their MFA Visiting Artist Program and Lecture Series. Kennedy was included in both the 2006 Oregon Biennials at the Portland Art Museum, her work has been published in Nudity in Groups. Kennedy began her long tenure at PICA as a volunteer and joined the Board of Trustees in 2002, she joined PICA's staff in 2003, managing public relations and marketing campaigns for the organization. In Summer 2005, Kennedy moved positions to manage the Visual Program. On November 28, 2017, Kennedy was promoted along with Roya Amirsoleymani and Erin Boberg Doughton as Artistic Directors. At PICA, Kennedy oversees the Precipice Fund, a grant for artist-run organizations and collaborative projects in Portland, Oregon, as part of the Andy Warhol Foundation for the Visual Arts’ Regional Regranting Program. Kennedy is represented by Fourteen30 Contemporary in Oregon, she sits on the advisory board for the Headlands Center for the Arts and is the former Board President of the Independent Publishing Resource Center.

Kennedy represents PICA as a member of several emerging consortiums including the Visual Art Network, a pilot project of the National Performance Network. She has served as a juror and advisor to several foundations and granting organizations, including Creative Capital, The Regional Arts and Culture Council, Southern Exposure's Alternate Exposure Grants among others. Kennedy was invited to participate in "Curating People," a symposium at The Arts Research Center at UC Berkeley on April 28 and 29, 2011. Fourteen30 Contemporary, Oregon 2017 Soloway, New York 2014 Fourteen30 Contemporary, Oregon 2013 Elizabeth Leach, Oregon 2005 Paint Off/Paint On, Halsey McKay Gallery, East Hampton, NY Kristan Kennedy/Gunta Stölzl, Z, Brooklyn, NY about desire, The White Box, Portland, OR OO, Misako & Rosen, Japan, curated by Rob Halverson/C-o-o-l Art NADA Hudson, Hudson, NY GOLD, Salon du Mecredi, Festival of Independants, Sint Nicholaas Lyceum, Amsterdam Interior Margins, curated by Stephanie Snyder, lumber room, Portland, OR The Quadratic Logogram of Almost Everything, curated by Derek Franklin, Half/Dozen, Portland OR Franklin, curated by Sam Korman, CarHole Gallery, Portland OR Impossible Instruments/Future Flags, curated by Nathaniel Price, Fourteen30 Contemporary, Portland, OR F.

W. P. C. Y. "…community declared itself a medium…", TBA Festival, Portland Institute for Contemporary Art, 2013 End Things, TBA Festival, Portland Institute for Contemporary Art, 2012 Between my head and my hand, there is always the face of death, Feldman Gallery + Project Space, Pacific Northwest College of Art, 2011 Evidence of Bricks, TBA Festival, Portland Institute for Contemporary Art, 2011 Fourteen 30 Contemporary Motley, John. "The Beauty in Things Usually Unseen," The Oregonian, June 14, 2013 Matt Stangel interviews Kennedy on curating End Things for PICA Kristan Kennedy on curating Interview with Kristan Kennedy Motley, John. "'Interior Margins,' featuring regional women artists working in abstraction," The Oregonian, November 30, 2011 Scott, Aaron. "Interior Margins at the Lumber Room," Portland Monthly, January 6, 2012 Radon, Lisa. "Less and More," Oregon ArtsWatch, January 28, 2012 Motley, John. "The Future is Now," Portland Mercury, January 8, 2009 Contemporary Art Daily: OO at Misako Rosen Kristan Kennedy tumblr