Parameterized XPath Views

We present a new approach for accelerating the execution of XPath expressions using parameterized materialized XPath views (PXV). While the approach is generic we show how it can be utilized in an XML extension for relational database systems. Furthermore we discuss an algorithm for automatically determining the best PXV candidates to materialize based on a given workload. We evaluate our approach and show the superiority of our cost based algorithm for determining PXV candidates over frequent pattern based algorithms

Spartan Daily, September 17, 2003

Volume 121, Issue 14https://scholarworks.sjsu.edu/spartandaily/9880/thumbnail.jp

Ultrasensitive surface enhanced Raman scattering nanomotors : for location predicable biochemical detection, single-cell bioanalysis, and controllable biochemical release and real-time detection

Localized surface plasmon resonance resulting from the concerted oscillations of conduction-band electrons in noble-metal (Au, Ag) nanostructures greatly induces enhanced electric ([italic E]) fields in confined nanoscale locations, such as on the tips of nanorods or in the junctions of nanodimers. These [italic E]-field enhanced locations are called hot spots. In the vicinity of hot spots, Raman scattering spectra of biochemicals can be substantially amplified with an [italic E]⁴ dependence due to the [italic E]-field enhancement of both the incident light and Raman spectra. This is called surface enhanced Raman scattering (SERS). SERS is known for its high sensitivity in providing fingerprint vibrational information of molecules. It has triggered intense interest because of its potential applications for label-free and multiplex biochemical detection relevant to medical, environmental and defense purposes. However, the tremendous potential of SERS for ultrasensitive detection has still not materialized because of four major obstacles: (1) it is extremely difficult to obtain a large number of hotspots for sensitive and reproducible detection due to the stringent requirement of hot spots of only a few nanometers; (2) it is arduous to achieve ultrasensitivity for the detection of a single/few molecules; (3) it is challenging to assemble the hot-spots at designated positions for location predicable sensing; and (4) it is even more difficult to change the state-of-the-art static/passive sensing schemes into dynamic/robotized schemes and also to incorporate multi-functionality into a single SERS nanostructure. In this research, we addressed the aforementioned problems by rational design, fabrication and robotization of ultrasensitive SERS nanomotor sensors. A nanomotor sensor consists of a tri-layer structure with a three-segment Ag/Ni/Ag nanorod as the core, a thin layer of silica in the center, and uniformly distributed Ag nanoparticles as the outer layer. The inner metallic nanorod core is the key structure in realizing the concept of the robotization of nanosensors, which can be electrically polarized and thus efficiently manipulated by electric tweezers. The presence of the Ni segment in the metallic nanowire core also allows manipulation and assembling by magnetic interactions. The central silica layer provides a supporting substrate for the synthesis of the Ag nanoparticles and separates the Ag nanoparticles from the metallic nanorod core to eliminate the effect of plasmonic quenching. Finally, the outermost layer made of Ag nanoparticles with optimized sizes and junctions provides a large number of hot spots (~1200/μm²) for ultrasensitive SERS detection with single molecule sensitivity and an enhancement factor (EF) of 1.1×10¹⁰. Moreover, two additional SERS enhancement mechanisms were investigated, i.e., the optical management with nanophotonic devices and the near field effect, which can readily increase the EF by 10 and 2 times, respectively, to at least 10¹¹. Finally, three applications of the SERS nanomotor sensors have been demonstrated: (1) the ultrasensitive SERS nanomotors were transported and assembled into a 3×3 array for location predicable sensing of multiplex molecules; (2) ultrasensitive SERS nanomotors were transported to individual living cells amidst many cells for single-cell bioanalysis; and (3) the SERS nanomotor sensors can be controlled to rotate by the electric tweezers for tunable biochemical release and detection. This research, exploring robotized nanosensors by integrating SERS and NEMS, is innovative in both material design and device concept, which could inspire a new device scheme for various bio-relevant applications.Materials Science and Engineerin

QuiiQ automation foundation

Tese de mestrado. Engenharia Informática. Faculdade de Engenharia. Universidade do Porto. 200

Efficiently correlating complex events over live and archived data streams

Correlating complex events over live and archived data streams, which we call Pattern Correlation Queries (PCQs), provides many benefits for domains which need real-time forecasting of events or identification of causal dependencies, while handling data at high rates and in massive amounts, like in financial or medical settings. Existing work has focused either on complex event processing over a single type of stream source (i.e., either live or archived), or on simple stream correlation queries (e.g., live events trigerring a database lookup). In this paper, we specifically focus on recency-based PCQs and provide clear, useful, and optimizable semantics for them. PCQs raise a number of challenges in optimizing data management and query processing, which we address in the setting of the DejaVu complex event processing system. More specifically, we propose three complementary optimizations including recent in-put buffering, query result caching, and join source ordering. Fur-thermore, we capture the relevant query processing tradeoffs in a cost model. An extensive performance study on synthetic and real-life data sets not only validates this cost model, but also shows that our optimizations are very effective, achieving more than two orders magnitude throughput improvement and much better scala-bility compared to a conventional approach

Organization and Information in the Fight against Crime: An Evaluation of the Integration of Police Forces in the State of Minas Gerais, Brazil

This paper explores the experience of information sharing, coordination, and integration of actions of the Civil and Military Polices in the state of Minas Gerais, Brazil, in the context of the IGESP program. The IGESP is based on the introduction of information management systems and organizational changes akin to those associated with COMPSTAT. All the evidence presented points to a causal effect of the IGESP on crime. The most conservative estimates indicate a reduction of 24% in property crimes and 13% in personal crimes. There is also evidence that the IGESP is associated with improved police response, measured by apprehension of weapons and clearance rates. We present one of the first set of causal estimates – with a clear identification strategy – of the impact of COMPSTAT-like programs. The results suggest that the coordination and informational gains represented by the program may constitute a first-order factor in a successful policy for fighting crime.crime, police, Brazil, COMPSTAT, impact evaluation

Multimodal Imaginaries and the “Big Worm”: Materialities, Artefacts and Analogies in São Paulo’s Urban Renovation

Recent interest in the multimodal accomplishment of organization has focused on the material and symbolic aspects of materiality. We argue that current literature invokes diverse “multimodal imaginaries”, that is, ways of conceiving the relation between the material and the conceptual, and that the different imaginaries support a plurality of perspectives on materiality. Using the empirical case of a large urban renewal project in São Paulo, Brazil, we illustrate three different multimodal imaginaries – the concrete, the semiotic, and the mimetic – and indicate how each imaginary determines the way in which the site in question is discursively constructed. After outlining the different approaches, we discuss their theoretical implications, advantages, and constraints, setting an agenda for future studies of materiality in organizational and institutional contexts