Time filter

Source Type

Pullman, WA, United States

Cockburn D.,1088 Rue Manning | Crabtree S.A.,Washington State University | Kohler T.A.,Dep
JASSS | Year: 2013

We introduce a model for agent specialization in small-scale human societies that incorporates planning based on social influence and economic state. Agents allocate their time among available tasks based on exchange, demand, competition from other agents, family needs, and previous experiences. Agents exchange and request goods using barter, balanced reciprocal exchange, and generalized reciprocal exchange. We use a weight-based reinforcement model for the allocation of resources among tasks. The Village Ecodynamics Project (VEP) area acts as our case study, and the work reported here extends previous versions of the VEP agent-based model ("Village"). This model simulates settlement and subsistence practices in Pueblo societies of the central Mesa Verde region between A.D. 600 and 1300. In the base model on which we build here, agents represent households seeking to minimize their caloric costs for obtaining enough calories, protein, fuel, and water from a landscape which is always changing due to both exogenous factors (climate) and human resource use. Compared to the baseline condition of no specialization, specialization in conjunction with barter increases population wealth, global population size, and degree of aggregation. Differences between scenarios for specialization in which agents use only a weight-based model for time allocation among tasks, and one in which they also consider social influence, are more subtle. The networks generated by barter in the latter scenario exhibit higher clustering coefficients, suggesting that social influence allows a few agents to assume particularly influential roles in the global exchange network. Source

Mendoza C.,Institute Ciencias | Bernes S.,National Autonomous University of Mexico | Torrens H.,Dep | Arroyo M.,Institute Ciencias
Organometallics | Year: 2010

Thermolysis reactions of [Os(SC6F5) 4(P(C6H4X-4)3)] (X = CF3 1, Cl 2, F 3, H 4, CH3 5, and OCH3 6) in refluxing toluene yield compounds [OsF(SC6F5)2(SC 6F4(SC6F5)-2)(P(C6H 4X-4)3)] (1a-6a) and [Os(SC6F5) 2(SC6F4(SC6F5)-2)(C 6H4X-4)] (1b-6b). In addition, [Os(SC6F 5)3(SC6F4(SC6F 5)-2)] (c) is yielded from 1-4 and 6, compounds [OsF(SC 6F5)3(P(C6H4X-4) 3)] [X = CF3 (1e), X = Cl (2e)] are also identified as products of the thermolysis reactions of 1 and 2, while [Os(SC6F 5)2(S2C6F4)(P(C 6H4CH3-4)3)] (5d) is obtained from 5. Compounds c, e, and d are produced in low yields (ca. 2-4%). Formation of all products involves the rupture of ortho C-F bonds. The first complexes systematically detected in these thermolysis reactions are compounds a, which are isomers of the starting complexes. Thus, the C-F activation involves the metal-mediated generation of the covalent Os-F bond. Single-crystal X-ray diffraction studies of the new compounds 4a, 5a, 2b-6b, 2e, and 5d indicate that these compounds consist of five-coordinated metal ions in essentially trigonal-bipyramidal geometries. In addition, thermolysis of the isolated compound [OsF(SC6F5)2(SC6F 4(SC6F5)-2)(P(C6H4CH 3-4)3)] (5a) in refluxing toluene gives rise to [Os(SC6F5)2(SC6F4(SC 6F5)-2)(C6H4CH3-4)] (5b) and [Os(SC6F5)2(S2C 6F4)(P(C6H4CH3-4) 3)] (5d), confirming that compounds a can generate compounds b when the thermolysis is prolonged. Compounds 1a-6a, 2b-6b, 1e, and 2e are investigated in solution by NMR studies, including variable-temperature 19F NMR experiments. These molecules are fluxional. Some of the activation parameters for the dynamic processes are determined. © 2010 American Chemical Society. Source

Lapina T.I.,Dep | Lapin D.V.,ul Volodarskogo | Petrik E.A.,Dep
International Review on Computers and Software | Year: 2014

In this paper introduces approach identification based on the handwritten signature and an method for Verification Data Handwritten Signature based on a normalization of measurement data from special device input signatures. This approach reduces the computational complexity of identification and can be used to many fields for the classification tasks and the secure transmission between two or more systems involved in communication. © 2014 Praise Worthy Prize S.r.l. All rights reserved. Source

Rojas N.,Dep | Grillasca Y.,Dep | Acosta A.,Dep | Audelo I.,Dep | De La Mora G.G.,Dep
Journal of Heterocyclic Chemistry | Year: 2013

Through the self-condensation of α-amino aldehydes, the synthesis of symmetrical disubstituted pyrazines was achieved in a three-step one-pot reaction. The α-amino aldehydes were easily obtained by treating methyl esters of natural α-amino acids with diisobutylaluminium hydride. © 2013 HeteroCorporation. Source

Discover hidden collaborations