A new model for selfish routing

AbstractIn this work, we introduce and study a new, potentially rich model for selfish routing over non-cooperative networks, as an interesting hybridization of the two prevailing such models, namely the KPmodel [E. Koutsoupias, C.H. Papadimitriou, Worst-case equilibria, in: G. Meinel, S. Tison (Eds.), Proceedings of the 16th Annual Symposium on Theoretical Aspects of Computer Science, in: Lecture Notes in Computer Science, vol. 1563, Springer-Verlag, 1999, pp. 404–413] and the Wmodel [J.G. Wardrop, Some theoretical aspects of road traffic research, Proceedings of the of the Institute of Civil Engineers 1 (Pt. II) (1952) 325–378].In the hybrid model, each of n users is using a mixed strategy to ship its unsplittable traffic over a network consisting of m parallel links. In a Nash equilibrium, no user can unilaterally improve its Expected Individual Cost. To evaluate Nash equilibria, we introduce Quadratic Social Cost as the sum of the expectations of the latencies, incurred by the squares of the accumulated traffic. This modeling is unlike the KP model, where Social Cost [E. Koutsoupias, C.H. Papadimitriou, Worst-case equilibria, in: G. Meinel, S. Tison (Eds.), Proceedings of the 16th Annual Symposium on Theoretical Aspects of Computer Science, in: Lecture Notes in Computer Science, vol. 1563, Springer-Verlag, 1999, pp. 404–413] is the expectation of the maximum latency incurred by the accumulated traffic; but it is like the W model since the Quadratic Social Cost can be expressed as a weighted sum of Expected Individual Costs. We use the Quadratic Social Cost to define Quadratic Coordination Ratio. Here are our main findings: •Quadratic Social Cost can be computed in polynomial time. This is unlike the #P-completeness [D. Fotakis, S. Kontogiannis, E. Koutsoupias, M. Mavronicolas, P. Spirakis, The structure and complexity of Nash equilibria for a selfish routing game, in: P. Widmayer, F. Triguero, R. Morales, M. Hennessy, S. Eidenbenz, R. Conejo (Eds.), Proceedings of the 29th International Colloquium on Automata, Languages and Programming, in: Lecture Notes in Computer Science, vol. 2380, Springer-Verlag, 2002, pp. 123–134] of computing Social Cost for the KP model.•For the case of identical users and identical links, the fully mixed Nash equilibrium [M. Mavronicolas, P. Spirakis, The price of selfish routing, Algorithmica 48 (1) (2007) 91–126], where each user assigns positive probability to every link, maximizes Quadratic Social Cost.•As our main result, we present a comprehensive collection of tight, constant (that is, independent of m and n), strictly less than 2, lower and upper bounds on the Quadratic Coordination Ratio for several, interesting special cases. Some of the bounds stand in contrast to corresponding super-constant bounds on the Coordination Ratio previously shown in [A. Czumaj, B. Vöcking, Tight bounds for worst-case equilibria, ACM Transactions on Algorithms 3 (1) (2007); E. Koutsoupias, M. Mavronicolas, P. Spirakis, Approximate equilibria and ball fusion, Theory of Computing Systems 36 (6) (2003) 683–693; E. Koutsoupias, C.H. Papadimitriou, Worst-case equilibria, in: G. Meinel, S. Tison (Eds.), Proceedings of the 16th Annual Symposium on Theoretical Aspects of Computer Science, in: Lecture Notes in Computer Science, vol. 1563, Springer-Verlag, 1999, pp. 404–413; M. Mavronicolas, P. Spirakis, The price of selfish routing, Algorithmica 48 (1) (2007) 91–126] for the KP model

Утилизация отходов биологического производства

В статье рассматривается проблема утилизации отходов, так как в год Экологии это тема стала актуальной. На каждом предприятии и в каждом доме увеличилось количество мусора и от этого страдает экологическая обстановка в каждом городе. В статье подробно узучена тема биологического производства. К биологическим отходам относятся ткани и органы, образующиеся в результате медицинской и ветеринарной оперативной практики, медико-биологических экспериментов, гибели скота, других животных и птиц, и другие отходы, получаемые при переработке пищевого и непищевого сырья животного происхождения, а также отходы биотехнологической промышленности.The article deals with the problem of waste disposal as in the year of the Environment this issue has become topical. Every enterprise and every household increased the amount of debris and suffers the environmental situation in each city. The article Azucena the theme of biological production. Biodegradable waste includes tissues and organs resulting from operational medical and veterinary practice, medical and biological experiments, loss of livestock, other animals and birds, and other waste obtained in the processing of food and non-food raw materials of animal origin and waste products of the biotechnology industry

Development of self-expanding Nitinol stents to enable percutaneous mitral valve replacement

Zur Vermeidung einer operativen Therapie konservativ nicht behandelbarer Mitralklappenerkrankungen wurde eine Stentform für einen perkutanen Klappenersatz entwickelt. Nach vorbereitenden anatomischen Studien und Anfertigung von Modellen erfolgten Einsatzversuche in Tierherzen. Dazu wurden Prototypen aus Gefäßprothesen angefertigt und, teils mittels Gefäßkathetern, eingebracht. Zwei der Stents erhielten Klappeneinsätze. Bei kathetergestützten Versuchsreihen mit den Stentprototypen wurden gute Eigenschaften in Bezug auf Einsatzfähigkeit, Sitz und Entfaltung der Klappen beobachtet. Die tierischen Klappeneinsätze schlossen meist suffizient bei guten Strömungsverhältnissen. Im Verlauf bewährte sich eine asymmetrische, eng an die anatomischen Gegebenheiten gebundene Form der Stents mit einer speziellen Befestigungsvorrichtung am anterioren Mitralsegel.A stent for percutaneous valve replacement was developed in order to avoid operations in diseases of the mitral valve that cannot be treated conservatively. Following anatomical studies and model construction, application in animal hearts was performed. For this purpose vascular prostheses were used to build prototypes. These were inserted in the hearts, partly by catheter devices. Valves were sown into two stents. The catheter based trials showed good stent insertion and placement ability and deployment of the valves. The animal valve grafts showed sufficient closure and good transvalvular flow. Best results were demonstrated by a stent with asymmetrical shape and a special anchorage to the anterior mitral valve leaflet

Layer-by-layer biofabrication of coronary covered stents with clickable elastin-like recombinamers

Producción CientíficaCoronary artery disease is the leading cause of death around the world. Endovascular stenting is the preferred treatment option to restore blood flow in the coronary arteries due to the lower perioperative morbidity when compared with more invasive treatment options. However, stent failure is still a major clinical problem, and further technological solutions are required to improve the performance of current stents. Here, we developed coronary stents covered with elastin-like recombinamers (ELRs) by exploiting a layer-by-layer technique combined with catalyst-free click chemistry. The resulting ELR-covered stents were intact after an in vitro simulated implantation procedure by balloon dilatation, which evidenced the elastic performance of the membrane. Additionally, the stents were mechanically stable under high flow conditions, which is in agreement with the covalent and stable nature of the click chemistry crosslinking strategy exploited during the ELR-membrane manufacturing and the successful embedding of the stent. Minimal platelet adhesion was detected after blood exposure in a Chandler loop as shown by scanning electron microscopy. The seeding of human endothelial progenitor cells (EPCs) on the ELR-membranes resulted in a confluent endothelial layer. These results prove the potential of this strategy to develop an advanced generation of coronary stents, with a stable and bioactive elastin-like membrane to exclude the atherosclerotic plaque from the blood stream or to seal coronary perforations and aneurysms, while providing a luminal surface with minimal platelet adhesion and favouring endothelialization.German federal and state governments (project StUpPD_330-18)Ministerio de Economía, Industria y Competitividad (projects PCIN-2015-010 / MAT2016-78903-R)Junta de Castilla y León (project VA317P18