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931.
The models used in social simulation to date have mostly been very simplistic cognitively, with little attention paid to the
details of individual cognition. This work proposes a more cognitively realistic approach to social simulation. It begins
with a model created by Gilbert (1997) for capturing the growth of academic science. Gilbert’s model, which was equation-based,
is replaced here by an agent-based model, with the cognitive architecture CLARION providing greater cognitive realism. Using
this cognitive agent model, results comparable to previous simulations and to human data are obtained. It is found that while
different cognitive settings may affect the aggregate number of scientific articles produced, they do not generally lead to
different distributions of number of articles per author. The paper concludes with a discussion of the correspondence between the model and the constructivist
view of academic science. It is argued that using more cognitively realistic models in simulations may lead to novel insights.
Isaac Naveh obtained a master’s degree in computer science at the University of Missouri. His research interests include hybrid cognitive
models and multi-agent learning.
Ron Sun is Professor of Cognitive Science at Rensselaer Polytechnic Institute, and formerly the James C. Dowell Professor of Engineering
and Professor of Computer Science at University of Missouri-Columbia. He received his Ph.D in 1992 from Brandeis University.
His research interest centers around studies of cognition, especially in the areas of cognitive architectures, human reasoning
and learning, cognitive social simulation, and hybrid connectionist models. For his paper on integrating rule-based and connectionist
models for accounting for human everyday reasoning, he received the 1991 David Marr Award from Cognitive Science Society.
He is the founding co-editor-in-chief of the journal Cognitive Systems Research, and also serves on the editorial boards of
many other journals. He is the general chair and program chair for CogSci 2006, and a member of the Governing Board of International
Neural Networks Society. His URL is: http://www.cogsci.rpi.edu/~rsun 相似文献
932.
Ron Aharoni 《Journal of Combinatorial Theory, Series A》1980,29(2):263-265
We characterize the extreme points of the polytope of symmetric doubly stochastic matrices of a given arbitrary order. 相似文献
933.
在真空介质中,由两种磁绝缘离子二极管产生的中性化离子束在横向磁场中B(?)400Gs传输了2m以上的距离 反磁信号以及极化电场测量证实:不论在低β0.01<β<1或在高β情况(1<β<300)下。束传输的机制都是由于的漂移结果。其中β=4πnm_1r_n~2·B~2。是束能量密度与横向磁场能量密度之比。在高β下,我们观察到磁场B向束中的快速扩散。本文对此进行了理论探讨 相似文献
934.
935.
The reactions of some organic diacids and their anhydrides with powdered ZnO were studied. The products are salts of approximately 1:1 mole composition. Their thermal stability is rather high, in comparison with their organic components. They are insoluble and usually cannot be recrystallized. It is suggested that anhydrides react with ZnO via their parent diacids, resulting initially in a half salt, as an intermediate product, followed by the formation of the normal salt. 相似文献
936.
Bruno Casetta Ron Bonner Bori Shushan Gianni Fior 《Journal of mass spectrometry : JMS》1992,27(3):211-214
The specific bovine and buffalo caseins have been characterized with the aim of using atmospheric pressure ionization mass spectrometry as an alternative to electrophoretic and immunological methods in the detection of the fraudulent addition of bovine milk to buffalo milk used in the production of speciality cheeses. 相似文献
937.
Three major applications have been found for rare-earth compounds in Metal Organic Chemical Vapour Depostion (MOCVD) or Chemical Vapour Deposition (CVD). Yttrium 2,2,6,6-tetramethyl-3,5-heptanedionates and 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionates have been used in conjunction with barium and copper(II) β-diketonates to deposit YBa2Cu3O7−δ as superconducting thin films. Rare-earth fluorides and chlorides have been used for CFD doping of rare earths into MOCVD-deposited ZnS, whilst yttrium chloride has been used, with barium iodide and copper(I) chloride, to produce YBa2Cu3O7−δ superconducting material by CVD. Lanthanoid (Ln) tris(cyclopentadienyl) compounds, Ln(C5H5)3 or Ln(C5H4Me)3, have been used for doping of rare earths into 13–15 (III–V) semiconductors. Their volatility, structure/volatility relationships, and preparations are discussed. Possible alternative reagents and problems to be faced in doping 12–16 (II–VI) semiconductors are also considered. 相似文献
938.
Abraham J. Domb Edith Mathiowitz Eyal Ron Steven Giannos Robert Langer 《Journal of polymer science. Part A, Polymer chemistry》1991,29(4):571-579
Unsaturated polyanhydrides of the structure ? [? (? CO? CH?CH? COO? )x? (? CO? R? COO? )y? ]n? , were synthesized. The polymers were prepared by either melt or solution polycondensation. Weight average molecular weights of up to 30,000 were obtained. The double bonds remain intact throughout the polymerization process and were available for a secondary reaction to form a crosslinked matrix. Poly(fumaric acid) is crystalline and insoluble in common organic solvents. Copolymers of fumaric acid with aliphatic diacids are less crystalline and soluble in chlorinated hydrocarbons. These copolymers displayed nearly constant degradation rates and drug release rates under physiological conditions. The time for complete degradation of 14 × 1.5 mm discs of poly(fumaric anhydride) and poly(sebacic anhydride) occurred in 2 and 15 days, respectively, while their copolymers degraded within this range. Further crosslinking of the polyanhydrids is demonstrated. 相似文献
939.
Lovász, Spencer and Vesztergombi proved that the linear discrepancy of a hypergraph H is bounded above by the hereditary discrepancy of H, and conjectured a sharper bound that involves the number of vertices in H. In this paper we give a short proof of this conjecture for hypergraphs of hereditary discrepancy 1. For hypergraphs of higher hereditary discrepancy we give some partial results and propose a sharpening of the conjecture.* A proof of the conjecture of Lovász, Spencer and Vesztergombi for hypergraphs of hereditary discrepancy 1 has also been independently obtained by B. Doerr [6]. Supported in part by NSF grant DMS-0100400. Research supported by the Technion V. P. R. Fund–M. and M. L. Bank Mathematics Research Fund and by the Fund for the Promotion of Research at the Technion. 相似文献
940.
Zheng X Aniol K Armstrong DS Averett TD Bertozzi W Binet S Burtin E Busato E Butuceanu C Calarco J Camsonne A Cates GD Chai Z Chen JP Choi S Chudakov E Cusanno F Leo RD Deur A Dieterich S Dutta D Finn JM Frullani S Gao H Gao J Garibaldi F Gilad S Gilman R Gomez J Hansen JO Higinbotham DW Hinton W Horn T De Jager CW Jiang X Kaufman L Kelly J Korsch W Kramer K LeRose J Lhuillier D Liyanage N Margaziotis DJ Marie F Markowitz P McCormick K Meziani ZE Michaels R Moffit B Nanda S Neyret D Phillips SK 《Physical review letters》2004,92(1):012004
We have measured the neutron spin asymmetry A(n)(1) with high precision at three kinematics in the deep inelastic region at x=0.33, 0.47, and 0.60, and Q(2)=2.7, 3.5, and 4.8 (GeV/c)(2), respectively. Our results unambiguously show, for the first time, that A(n)(1) crosses zero around x=0.47 and becomes significantly positive at x=0.60. Combined with the world proton data, polarized quark distributions were extracted. Our results, in general, agree with relativistic constituent quark models and with perturbative quantum chromodynamics (PQCD) analyses based on the earlier data. However they deviate from PQCD predictions based on hadron helicity conservation. 相似文献