Near-optimal adjacency labeling scheme for power-law graphs

An adjacency labeling scheme is a method that assigns labels to the vertices of a graph such that adjacency between vertices can be inferred directly from the assigned label, without using a centralized data structure. We devise adjacency labeling schemes for the family of power-law graphs. This family that has been used to model many types of networks, e.g. the Internet AS-level graph. Furthermore, we prove an almost matching lower bound for this family. We also provide an asymptotically near- optimal labeling scheme for sparse graphs. Finally, we validate the efficiency of our labeling scheme by an experimental evaluation using both synthetic data and real-world networks of up to hundreds of thousands of vertices

Near Optimal Adjacency Labeling Schemes for Power-Law Graphs

An adjacency labeling scheme labels the n nodes of a graph with bit strings in a way that allows, given the labels of two nodes, to determine adjacency based only on those bit strings. Though many graph families have been meticulously studied for this problem, a non-trivial labeling scheme for the important family of power-law graphs has yet to be obtained. This family is particularly useful for social and web networks as their underlying graphs are typically modelled as power-law graphs. Using simple strategies and a careful selection of a parameter, we show upper bounds for such labeling schemes of ~O(sqrt^{alpha}(n)) for power law graphs with coefficient alpha;, as well as nearly matching lower bounds. We also show two relaxations that allow for a label of logarithmic size, and extend the upper-bound technique to produce an improved distance labeling scheme for power-law graphs

Dynamic and Multi-functional Labeling Schemes

We investigate labeling schemes supporting adjacency, ancestry, sibling, and connectivity queries in forests. In the course of more than 20 years, the existence of $\log n + O(\log \log)$ labeling schemes supporting each of these functions was proven, with the most recent being ancestry [Fraigniaud and Korman, STOC '10]. Several multi-functional labeling schemes also enjoy lower or upper bounds of $\log n + \Omega(\log \log n)$ or $\log n + O(\log \log n)$ respectively. Notably an upper bound of $\log n + 5\log \log n$ for adjacency+siblings and a lower bound of $\log n + \log \log n$ for each of the functions siblings, ancestry, and connectivity [Alstrup et al., SODA '03]. We improve the constants hidden in the $O$-notation. In particular we show a $\log n + 2\log \log n$ lower bound for connectivity+ancestry and connectivity+siblings, as well as an upper bound of $\log n + 3\log \log n + O(\log \log \log n)$ for connectivity+adjacency+siblings by altering existing methods. In the context of dynamic labeling schemes it is known that ancestry requires $\Omega(n)$ bits [Cohen, et al. PODS '02]. In contrast, we show upper and lower bounds on the label size for adjacency, siblings, and connectivity of $2\log n$ bits, and $3 \log n$ to support all three functions. There exist efficient adjacency labeling schemes for planar, bounded treewidth, bounded arboricity and interval graphs. In a dynamic setting, we show a lower bound of $\Omega(n)$ for each of those families.Comment: 17 pages, 5 figure

Sanctions and the Inherent Power: The Supreme Court Expands the American Rule\u27s Bad Faith Exception for Fee Shifting-Chambers v. NASCO, Inc.

Confronted with the growing problem of crowded dockets, federal courts have enacted and imposed a variety of rules and sanctions designed to discourage abuse of the judicial proces

El rol del estado en la regulación del crecimiento urbano : Los casos de Buenos Aires y Sydney

La siguiente ponencia plantea algunos aspectos que consideramos centrales para comprender el rol que cumple el Estado como agente regulador del crecimiento urbano en las regiones metropolitanas de Buenos Aires (Argentina) y Sydney (Australia). En la primera parte se repasa cómo fue la evolución histórica de estas ciudades y las características del crecimiento actual. Luego se analizan las proyecciones de población y vivienda para ambas metrópolis y los modos en que pueden absorber el crecimiento propuesto. Por último interesa evaluar el papel diferencial que cumple el Estado en la regulación del desarrollo urbano en ambas ciudades.The following article presents some aspects that are central to understanding the role played by the state as a regulator of urban growth in the metropolitan regions of Buenos Aires, Argentina and Sydney, Australia. In the first part, the historical evolution of these cities is reviewed and the characteristics of current growth patterns. Then the population and housing projections are analysed for both cities, as is the ways they can absorb the projected growth. Finally is assesses the differential role played by the State in the regulation of urban development in both cities.Eje 2: Forma y estructura urbana, organización del territorio, orientación del crecimiento.Facultad de Arquitectura y Urbanism

Physisorption-based charge transfer in two-dimensional SnS2 for selective and reversible NO2 gas sensing

Nitrogen dioxide (NO2) is a gas species that plays an important role in certain industrial, farming, and healthcare sectors. However, there are still significant challenges for NO2 sensing at low detection limits, especially in the presence of other interfering gases. The NO2 selectivity of current gas-sensing technologies is significantly traded-off with their sensitivity and reversibility as well as fabrication and operating costs. In this work, we present an important progress for selective and reversible NO2 sensing by demonstrating an economical sensing platform based on the charge transfer between physisorbed NO2 gas molecules and two-dimensional (2D) tin disulfide (SnS2) flakes at low operating temperatures. The device shows high sensitivity and superior selectivity to NO2 at operating temperatures of less than 160 °C, which are well below those of chemisorptive and ion conductive NO2 sensors with much poorer selectivity. At the same time, excellent reversibility of the sensor is demonstrated, which has rarely been observed in other 2D material counterparts. Such impressive features originate from the planar morphology of 2D SnS2 as well as unique physical affinity and favorable electronic band positions of this material that facilitate the NO2 physisorption and charge transfer at parts per billion levels. The 2D SnS2-based sensor provides a real solution for low-cost and selective NO2 gas sensing

El rol del estado en la regulación del crecimiento urbano : Los casos de Buenos Aires y Sydney

La siguiente ponencia plantea algunos aspectos que consideramos centrales para comprender el rol que cumple el Estado como agente regulador del crecimiento urbano en las regiones metropolitanas de Buenos Aires (Argentina) y Sydney (Australia). En la primera parte se repasa cómo fue la evolución histórica de estas ciudades y las características del crecimiento actual. Luego se analizan las proyecciones de población y vivienda para ambas metrópolis y los modos en que pueden absorber el crecimiento propuesto. Por último interesa evaluar el papel diferencial que cumple el Estado en la regulación del desarrollo urbano en ambas ciudades.The following article presents some aspects that are central to understanding the role played by the state as a regulator of urban growth in the metropolitan regions of Buenos Aires, Argentina and Sydney, Australia. In the first part, the historical evolution of these cities is reviewed and the characteristics of current growth patterns. Then the population and housing projections are analysed for both cities, as is the ways they can absorb the projected growth. Finally is assesses the differential role played by the State in the regulation of urban development in both cities.Eje 2: Forma y estructura urbana, organización del territorio, orientación del crecimiento.Facultad de Arquitectura y Urbanism