Flattening an object algebra to provide performance

Algebraic transformation and optimization techniques have been the method of choice in relational query execution, but applying them in object-oriented (OO) DBMSs is difficult due to the complexity of OO query languages. This paper demonstrates that the problem can be simplified by mapping an OO data model to the binary relational model implemented by Monet, a state-of-the-art database kernel. We present a generic mapping scheme to flatten data models and study the case of straightforward OO model. We show how flattening enabled us to implement a query algebra, using only a very limited set of simple operations. The required primitives and query execution strategies are discussed, and their performance is evaluated on the 1-GByte TPC-D (Transaction-processing Performance Council's Benchmark D), showing that our divide-and-conquer approach yields excellent result

Gryphon M^3 system: integration of MEMS for flight control

By using distributed arrays of micro-actuators as effectors, micro-sensors to detect the optimal actuation location, and microelectronics to provide close loop feedback decisions, a low power control system has been developed for controlling a UAV. Implementing the Microsensors, Microactuators, and Microelectronics leads to what is known as a M^3 (M-cubic) system. This project involves demonstrating the concept of using small actuators (approximately micron-millimeter scale) to provide large control forces for a large-scale system (approximately meter scale) through natural flow amplification phenomenon. This is theorized by using fluid separation phenomenon, vortex evolution, and vortex symmetry on a delta wing aircraft. By using MEMS actuators to control leading edge vortex separation and growth, a desired aerodynamic force can be produced about the aircraft for flight control. Consequently, a MEMS shear stress sensor array was developed for detecting the leading edge separation line where leading edge vortex flow separation occurs. By knowing the leading edge separation line, a closely coupled micro actuation from the effectors can cause the required separation that leads to vortex control. A robust and flexible balloon type actuator was developed using pneumatic pressure as the actuation force. Recently, efforts have started to address the most elusive problem of amplified distributed control (ADC) through data mining algorithms. Preliminary data mining results are promising and this part of the research is ongoing. All wind tunnel data used the baseline 56.5 degree(s) sweepback delta wing with root chord of 31.75 cm

A language and an execution model for the detection of active situations

This paper presents a thesis about a language and an execution model for the detection of situations aimed at reducing the complexity of active applications. This work has been motivated by the observation that in many cases, there is a gap between current tools that enable to react to a single event (following the ECA: Event – condition – action paradigm), and the reality, in which a single event may not require any reaction, however the reaction should be given to patterns over the event history. The concept of situation presented in this paper, extends the concept of composite event, in its expressive power, flexibility, and usability. This paper motivates the work, surveys other efforts in this are, and presents preliminary ideas for both the language and the execution model

Marking time in sequence mining

Sequence mining is often conducted over static and temporal datasets as well as over collections of events (episodes). More recently, there has also been a focus on the mining of streaming data. However, while many sequences are associated with absolute time values, most sequence mining routines treat time in a relative sense, only returning patterns that can be described in terms of Allen-style relationships (or simpler). In this work we investigate the accommodation of timing marks within the sequence mining process. The paper discusses the opportunities presented and the problems that may be encountered and presents a novel algorithm, INTEMTM, that provides support for timing marks. This enables sequences to be examined not only in respect of the order and occurrence of tokens but also in terms of pace. Algorithmic considerations are discussed and an example provided for the case of polled sensor data.Sydney, NS

Vibrating a small plate vortex generator to improve control robustness of a micro aerial delta wing vehicle

In the work, vortex generators as a small vibrating plates adjusted to a delta wing surface are used for boundary layer control (BLC). The vortex generators applied to produce aircraft moments and aerodynamic forces are proposed and tested. The BLC for delta wing micro aircraft is calculated numerically by using fluid-structure interactions. The Navier-Stokes equations and Shear Stress Transport (SST) model were used for numerical calculations. The flexible oscillating small plates driven by controlled piezo stacks and their influence on the air flow in the delta boundary layer are investigated. The amplitude of the piezo stack vortex generator and frequency measurements are presented

Gryphon M^3 system: integration of MEMS for flight control

By using distributed arrays of micro-actuators as effectors, micro-sensors to detect the optimal actuation location, and microelectronics to provide close loop feedback decisions, a low power control system has been developed for controlling a UAV. Implementing the Microsensors, Microactuators, and Microelectronics leads to what is known as a M^3 (M-cubic) system. This project involves demonstrating the concept of using small actuators (approximately micron-millimeter scale) to provide large control forces for a large-scale system (approximately meter scale) through natural flow amplification phenomenon. This is theorized by using fluid separation phenomenon, vortex evolution, and vortex symmetry on a delta wing aircraft. By using MEMS actuators to control leading edge vortex separation and growth, a desired aerodynamic force can be produced about the aircraft for flight control. Consequently, a MEMS shear stress sensor array was developed for detecting the leading edge separation line where leading edge vortex flow separation occurs. By knowing the leading edge separation line, a closely coupled micro actuation from the effectors can cause the required separation that leads to vortex control. A robust and flexible balloon type actuator was developed using pneumatic pressure as the actuation force. Recently, efforts have started to address the most elusive problem of amplified distributed control (ADC) through data mining algorithms. Preliminary data mining results are promising and this part of the research is ongoing. All wind tunnel data used the baseline 56.5 degree(s) sweepback delta wing with root chord of 31.75 cm