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Dimofte T.,California Institute of Technology | Gukov S.,California Institute of Technology | Gukov S.,University of California at Santa Barbara | Soibelman Y.,KSU
Letters in Mathematical Physics | Year: 2011

We study refined and motivic wall-crossing formulas in N = 2 supersymmetric gauge theories with SU(2) gauge group and Nf < 4 matter hypermultiplets in the fundamental representation. Such gauge theories provide an excellent testing ground for the conjecture that "refined = motivic." © 2010 Springer. Source

Kontsevich M.,I.H.E.S. | Soibelman Y.,KSU
Communications in Number Theory and Physics | Year: 2011

To a quiver with potential we assign an algebra in the category of exponential mixed Hodge structures (the latter is also introduced in the paper). We compute the algebra (which we call Cohomological Hall algebra) for quivers without potential and study factorization properties of its Poincaré-Hilbert series in general case. As an application we obtain an alternative approach to our theory of motivic Donaldson-Thomas invariants of 3-dimensional Calabi-Yau categories and prove their integrality properties. We discuss the relationship of Cohomological Hall algebra with other mathematical structures including cluster algebras and Chern- Simons theory. Source

Rikli N.-E.,KSU
2012 IEEE International Conference on Wireless Information Technology and Systems, ICWITS 2012 | Year: 2012

The design of a fast and efficient media independent handover function (MIHF) for a 4G mobile supporting heterogeneous networks is the goal of this paper. This will be carried out for two classes of traffic with different quality of service requirements. Due to the imprecision and fast variability of the measured or estimated input parameters, the corresponding decision engines to be used in the MIHF, were based on fuzzy logic design. Three parameters are to be considered: the signal strength, the available bandwidth, and the connection cost. The two designed funtions showed a clear adaptability to the requirements of the two considered classes of traffic. © 2012 IEEE. Source

KuKanich K.S.,Kansas State University | Kaur R.,KSU | Freeman L.C.,Northern Illinois University | Powell D.A.,Northern Illinois University
American Journal of Nursing | Year: 2013

OBJECTIVE: To improve hand hygiene in two outpatient health care clinics through the introduction of a gel sanitizer and an informational poster. METHODS: In this interventional study, health care workers at two outpatient clinics were observed for frequency of hand hygiene (attempts versus opportunities). Gel sanitizer and informational posters were introduced together as an intervention. Direct observation of the frequency of hand hygiene was performed during baseline, intervention, and follow-up. A poststudy survey of health care workers was also distributed and collected. RESULTS: In both clinics, the frequency of hand hygiene was poor at baseline (11% and 21%) but improved significantly after intervention (36% and 54%) and was maintained through the follow-up period (32% and 51%). Throughout the study, postcontact hand hygiene was observed significantly more often than precontact hand hygiene. In both clinics, health care workers reported a preference for soap and water; yet observations showed that when the intervention made gel sanitizer available, sanitizer use predominated. Fifty percent of the surveyed health care workers considered the introduction of gel sanitizer to be an effective motivating tool for improving hand hygiene. CONCLUSIONS: Hand hygiene performance by health care workers in outpatient clinics may be improved through promoting the use of gel sanitizer and using informational posters. Compared with surveys, direct observation by trained observers may provide more accurate information about worker preferences for hand hygiene tools. Source

Tsai C.-M.,KSU | Fang Y.-C.,NKFUST
2012 Symposium on Photonics and Optoelectronics, SOPO 2012 | Year: 2012

This paper focuses on the improvement of the Petzval field curvature aberration that is induced by the lens curvature and refractive index. Most primary aberrations can be effectively corrected by using aspherical lens while the Petzval filed curvature regarded as intrinsic to an optical system cannot easy be corrected through the high order coefficient of aspherical lens. With the global optimization of the genetic algorithm (GA), this study applies the basic selection, crossover and mutation operator to optimize a group of lens curvatures and thicknesses so that not only the Petzval field curvature aberration is effectively improved but also the specification requirement is met in a projector system. © 2012 IEEE. Source

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