172,008 research outputs found
Molecular and solid-state (8-hydroxy-quinoline)aluminum interaction with magnesium: A first-principles study
No full textThe interaction between Mg and (8-hydroxyquinoline)aluminum, Alq(3), is investigated via ab initio molecular dynamics based on density-functional theory. We model the Alq(3) thin film both with a single Alq(3) molecule in vacuo (as is usually done in the literature) and with an Alq(3) crystalline structure. Comparing the results from these two models, we show that bulk calculations provide a better description of the chemical processes involved, allowing the Mg atom to react with two neighboring Alq(3) molecules, as was alluded to in a previous publication [S. Meloni, A. Palma, A. Kahn, J. Schwartz, and R. Car, J. Am. Chem. Soc. 125, 7808 (2003)]. Moreover, core-level shift calculations are in good agreement with experimental measurements only when using the solid phase approach. We also propose a different interpretation of the Al(2p) experimental core level presented in a previous work [C. Shen, A. Kahn, and J. Schwartz, J. Appl. Phys. 89, 449 (2001)]
Oral history interview with Robert E. Kahn
No full textCopyright to this oral history is held by Robert E. Kahn.Kahn briefly discusses his educational background and involvement with the development of ARPANET before focusing on the operations of the Information Processing Techniques Office (IPTO) of the Defense Advanced Research Projects Agency (DARPA). Kahn describes the development of computer networks with DARPA support and explains the process of contracting research at DARPA as well as the creation of DARPA budgets in detail. In this context he discusses the work of various DARPA and IPTO personnel including J. C. R. Licklider, Vinton Cerf, Larry Roberts, and George Heilmeier. This interview was recorded as part of a research project on the influence of the Defense Advanced Research Projects Agency (DARPA) on the development of computer science in the United States.Kahn, Robert E.. (1989). Oral history interview with Robert E. Kahn. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/107380
The defender of the Marshallian tradition: Shove and his correspondence with Kahn, J. Robinson and Sraffa
No full textIl saggio, come tutti gli altri nel libro, è basato sulla corrispondenza finora non pubblicata che ci è pervenuta tra G. Shove, figura autorevole ma meno nota della Cambridge tra le due guerre, e Sraffa, J. Robinson e R. Kahn. I temi affrontati sono relativi alla teoria dell'impresa, alla controversia sui rendimenti aperta dall'articolo di Sraffa del 1926 sull'EJ, alla interpretazione di Marshall
Louis Kahn e l'architettura dell'educazione. Louis Kahn and the Architecture of Education
No full textIl pensiero di Louis Kahn sull'educazione in architetturaThe thinking about education in architecture by Louis Kah
Sarah Kahn
No full textSarah Kahn (Cohen) was the widow of Samuel Kahn. Samuel Kahn was a Jewish pioneer and merchant
THE LOW-LYING ELECTRONIC STATES OF HgCl AND HgBr
No full text L. R, Kahn, P. J. Hay, and R. D. Cowan, J, Chem. Phys., in press. L. R. Kahn, P. Baybutt, and D. G. Truhlar, J. Chem. Phys. 65, 3826 (1976). ""Author Institution: Los Alamos Scientific Laboratory; Los Alamos Scientific Laboratory, Battelle Columbus LaboratoriesAb initio configuration interaction calculations are reported on the Low-lying electronic states of HgCl and HgBr. The calculations employ a relativistic effective core on Hg and nonrelativistic effective core on chlorine and bromine. Emission energies and spectroscopic constants for the lasing transition are compared to experiment. Spin-orbit coupling effects are included using a simple, effective, one-electron spin-orbit operator. The production of electronically excited HgCl and HgBr by photodissociation of and will be considered briefly
On Joan Robinson’s role in creating the myth that R. Kahn originated the multiplier concept
No full textAn enduring myth accepted by all Orthodox and heterodox economists is that it was Richard Kahn who discovered and originated the concept of the multiplier. Kahn then supposedly showed Keynes how the multiplier concept could be specified mathematically so as to provide hard support for Keynes’s views in the late 1920s about increased initial government spending on public infrastructure generating much larger increases in total spending than the original injection, leading to decreasing levels of unemployment. There are three major problems with this story. First, Kahn, himself, in a 1936 response to Hans Neisser in the Review of Economics and Statistics stated that most of his ideas about the multiplier concept came from Keynes. Second, the mathematical and logical development of the multiplier concept had already been formalized and formulated precisely by Keynes in 1921 on p. 315 in footnote 1 of the A Treatise on Probability in section 8 of chapter 26. Third, Keynes provided an arithmetic example of the mathematical technique worked out in the A Treatise on Probability in May, 1929 (Kent, 2007). There is simply no foundation for the myth, promoted by Joan Robinson, that Kahn was the author of the multiplier concept. Kahn went along with Robinson because he was involved in a 54-year old relationship with Joan Robinson. Keynes taught Kahn the theory of the multiplier concept and left it up to Kahn to write a full blown article on it, which was then published by Keynes in the June,1931 issue of the Economic Journal
Kahn Process Networks and a Reactive Extension
No full textKahn and MacQueen have introduced a generic class of determinate asynchronous data-flow applications, called Kahn Process Networks (KPNs) with an elegant mathematical model and semantics in terms of Scott-continuous functions on data streams together with an implementation model of independent asynchronous sequential programs communicating through FIFO buffers with blocking read and non-blocking write operations. The two are related by the Kahn Principle which states that a realization according to the implementation model behaves as predicted by the mathematical function. Additional steps are required to arrive at an actual implementation of a KPN to take care of scheduling of independent processes on a single processor and to manage communication buffers. Because of the expressiveness of the KPN model, buffer sizes and schedules cannot be determined at design time in general and require dynamic run-time system support. Constraints are discussed that need to be placed on such system support so as to maintain the Kahn Principle. We then discuss a possible extension of the KPN model to include the possibility for sporadic, reactive behavior which is not possible in the standard model. The extended model is called Reactive Process Networks. We introduce its semantics, look at analyzability and at more constrained data-flow models combined with reactive behavior.</p
Kahn Process Networks and a Reactive Extension
No full textKahn and MacQueen have introduced a generic class of determinate asynchronous data-flow applications, called Kahn Process Networks (KPNs) with an elegant mathematical model and semantics in terms of Scott-continuous functions on data streams together with an implementation model of independent asynchronous sequential programs communicating through FIFO buffers with blocking read and non-blocking write operations. The two are related by the Kahn Principle which states that a realization according to the implementationmodel behaves as predicted by the mathematical function. Additional steps are required to arrive at an actual implementation of a KPN to take care of scheduling of independent processes on a single processor and to manage communication buffers. Because of the expressiveness of the KPN model, buffer sizes and schedules cannot be determined at design time in general and require dynamic run-time system support. Constraints are discussed that need to be placed on such system support so as to maintain the Kahn Principle. We then discuss a possible extension of the KPN model to include the possibility for sporadic, reactive behavior which is not possible in the standard model. The extended model is called Reactive Process Networks. We introduce its semantics, look at analyzability and at more constrained data-flowmodels combined with reactive behavior
Kahn process networks and a reactive extension
No full textKahn and MacQueen have introduced a generic class of determinate asynchronous data-flow applications, called Kahn Process Networks (KPNs) with an elegant mathematical model and semantics in terms of Scott-continuous functions on data streams together with an implementation model of independent asynchronous sequential programs communicating through FIFO buffers with blocking read and non-blocking write operations. The two are related by the Kahn Principle which states that a realization according to the implementation model behaves as predicted by the mathematical function. Additional steps are required to arrive at an actual implementation of a KPN to take care of scheduling of independent processes on a single processor and to manage communication buffers. Because of the expressiveness of the KPN model, buffer sizes and schedules cannot be determined at design time in general and require dynamic run-time system support. Constraints are discussed that need to be placed on such system support so as to maintain the Kahn Principle.We then discuss a possible extension of the KPN model to include the possibility for sporadic, reactive behavior which is not possible in the standard model. The extended model is called Reactive Process Networks. We introduce its semantics, look at analyzability and at more constrained data-flow models combined with reactive behavior
- …
