STRATUM: A METHODOLOGY FOR DESIGNING HEURISTIC AGENT NEGOTIATION STRATEGIES

Automated negotiation is a powerful (and sometimes essential) means for allocating resources among self-interested autonomous software agents. A key problem in building negotiating agents is the design of the negotiation strategy, which is used by an agent to decide its negotiation behavior. In complex domains, there is no single, obvious optimal strategy. This has led to much work on designing heuristic strategies, where agent designers usually rely on intuition and experience. In this article, we introduce STRATUM, a methodology for designing strategies for negotiating agents. The methodology provides a disciplined approach to analyzing the negotiation environment and designing strategies in light of agent capabilities and acts as a bridge between theoretical studies of automated negotiation and the software engineering of negotiation applications. We illustrate the application of the methodology by characterizing some strategies for the Trading Agent Competition and for argumentation-based negotiation.     

Controlling Plasmon‐Enhanced Fluorescence via Intersystem Crossing in Photoswitchable Molecules

By harnessing photoswitchable intersystem crossing (ISC) in spiropyran (SP) molecules, active control of plasmon‐enhanced fluorescence in the hybrid systems of SP molecules and plasmonic nanostructures is achieved. Specifically, SP‐derived merocyanine (MC) molecules formed by photochemical ring‐opening reaction display efficient ISC due to their zwitterionic character. In contrast, ISC in quinoidal MC molecules formed by thermal ring‐opening reaction is negligible. The high ISC rate can improve fluorescence quantum yield of the plasmon‐modified spontaneous emission, only when the plasmonic electromagnetic field enhancement is sufficiently high. Along this line, extensive photomodulation of fluorescence is demonstrated by switching the ISC in MC molecules at Au nanoparticle aggregates, where strongly enhanced plasmonic hot spots exist. The ISC‐mediated plasmon‐enhanced fluorescence represents a new approach toward controlling the spontaneous emission of fluorophores near plasmonic nanostructures, which expands the applications of active molecular plasmonics in information processing, biosensing, and bioimaging.     

Phase transitions and assortativity in models of gene regulatory networks evolved under different selection processes

We study a simplified model of gene regulatory network evolution in which links (regulatory interactions) are added via various selection rules that are based on the structural and dynamical features of the network nodes (genes). Similar to well-studied models of ‘explosive’ percolation, in our approach, links are selectively added so as to delay the transition to large-scale damage propagation, i.e. to make the network robust to small perturbations of gene states. We find that when selection depends only on structure, evolved networks are resistant to widespread damage propagation, even without knowledge of individual gene propensities for becoming ‘damaged’. We also observe that networks evolved to avoid damage propagation tend towards disassortativity (i.e. directed links preferentially connect high degree ‘source’ genes to low degree ‘target’ genes and vice versa). We compare our simulations to reconstructed gene regulatory networks for several different species, with genes and links added over evolutionary time, and we find a similar bias towards disassortativity in the reconstructed networks.     

Spatial Analysis of Metal–PLGA Hybrid Microstructures Using 3D SERS Imaging

The incorporation of gold nanoparticles in biodegradable polymeric nanostructures with controlled shape and size is of interest toward different applications in nanomedicine. Properties of the polymer such as drug loading and antibody functionalization can be combined with the plasmonic properties of gold nanoparticles, to yield advanced hybrid materials. This study presents a new way to synthesize multicompartmental microgels, fibers, or cylinders, with embedded anisotropic gold nanoparticles. Gold nanoparticles dispersed in an organic solvent can be embedded within the poly(lactic‐co‐glycolic acid) (PLGA) matrix of polymeric microstructures, when prepared via electrohydrodynamic co‐jetting. Prior functionalization of the plasmonic nanoparticles with Raman active molecules allows for imaging of the nanocomposites by surface‐enhanced Raman scattering (SERS) microscopy, thereby revealing nanoparticle distribution and photostability. These exceptionally stable hybrid materials, when used in combination with 3D SERS microscopy, offer new opportunities for bioimaging, in particular when long‐term monitoring is required.     

A formal analysis of interest-based negotiation

In multi-agent systems (MAS), negotiation provides a powerful metaphor for automating the allocation and reallocation of resources. Methods for automated negotiation in MAS include auction-based protocols and alternating offer bargaining protocols. Recently, argumentation-based negotiation has been accepted as a promising alternative to such approaches. Interest-based negotiation (IBN) is a form of argumentation-based negotiation in which agents exchange (1) information about their underlying goals; and (2) alternative ways to achieve these goals. However, the usefulness of IBN has been mostly established in the literature by appeal to intuition or by use of specific examples. In this paper, we propose a new formal model for reasoning about interest-based negotiation protocols. We demonstrate the usefulness of this framework by defining and analysing two different IBN protocols. In particular, we characterise conditions that guarantee their advantage (in the sense of expanding the set of individual rational deals) over the more classic proposal-based approaches to negotiation.     

Kinetic Resolution of 1‐Biaryl‐ and 1‐(Pyridylphenyl)alkan‐1‐ols Catalysed by the Lipase B from Candida antarctica

Lipase B from Candida antarctica (CAL‐B) catalyses the highly enantioselective (E>200) transesterification of some 1‐biaryl‐2‐yl‐, ‐3‐yl‐, and ‐4‐ylethanols and ‐propan‐1‐ols, as well as 1‐(o‐, m‐, and p‐pyridylphenyl)ethanols, 6 , with vinyl acetate, Kazlauskas' rule being obeyed in all cases. meta and para‐Substituted substrates were transformed within several hours (conversion degree ranging from 23–50%), reaction rates for propan‐1‐ol derivatives being slower than those for ethanol derivatives. Transesterifications of ortho‐substituted alcohols took several days and were accompanied by a chemoenzymatic side reaction: the formation of another acetate derived from the hemiacetal between 6 and acetaldehyde coming from vinyl acetate. This side reaction was suppressed in the presence of isopropenyl acetate as acyl donor, conversion degrees for transesterification ranging from 20–40% after ten days (E>200). The usefulness of (R)‐ 6p as ligand in the asymmetric addition of diethylzinc to benzaldehyde was also demonstrated.