Applications of data analysis techniques for oil production prediction

This paper describes two data analysis techniques adopted in a Decision Support System (DSS) that aids users in predicting oil production of an infill well. The system generates predictions in the form of a possible range of cumulative production and length of production life of an infill well. The system also shows the worst and best case scenarios based on different production curves so that the expert can examine the plots of predicted production rates for each existing well and decide which model gives the best fit. The production curve of each individual well was mathematically modeled so that production values beyond the historical data can be produced. Decline curve estimation and neural network approaches were adopted for data analysis in the system. The system was tested with data from two groups of wells from two different fields in Saskatchewan, Canada. Observations on the suitable duration that the historical data set should cover and a comparison among different curve estimation and neural network models are presented.     

Improved Repeatability of Pulsed Field Magnetometry Measurements Through Peltier Effect Temperature Control of Measurement Coils

Pulsed Field Magnetometers (PFMs) offer a method for high speed full loop characterisation of hard magnetic materials. As there is no dependency on iron to close a circuit, the repeatability of the technique is good. By utilising Peltier effect techniques to control the temperature of the measurement coil systems employed in a Pulsed Field Magnetometer, the level of repeatability of measurements can be significantly improved.     

Towards a more efficient energy use in photovoltaic powered products

This paper analyzes the energy saving and power management solutions necessary to improve the energy consumption efficiency in photovoltaic powered products. Important in the design of such products is not only the energy supply optimization required to deliver the actual energy to fulfil their function, but also efficient energy transfer along the energy chain. In this paper, several methods to improve the efficiency of the energy chain are described. This includes an analysis of optimization methods for photovoltaic powered products, its functional system and product use.     

Some remarks on the reactor network synthesis for gold cyanidation

Gold cyanidation in most of the plants occurs in a cascade of large tanks because this configuration offers the longest residence time and consequently the highest gold recovery. However, the long contact between the ore and the leaching solution can increases the reactants consumption by side reactions, and in some cases this conventional reactor configuration will not be the most suitable. In this paper, several configurations for a gold leaching circuit with five equal-sized reactors are investigated and the effect of different network configurations on the process performance addressed. It is showed that, for high gold content and low cyanide concentration the conventional in-series configuration is the most recommended; however, for high cyanide concentration and low gold content the in-parallel configuration is the best one. For intermediate values of gold content and cyanide concentration, hybrid configurations with parallel sections at the beginning of the circuit are the best choice. It is also showed that the optimal circuit configuration strongly depends on the gold price and cyanide cost, and for low values of cyanide price the conventional in-series configuration is the most recommended, while for high cyanide prices the hybrid and parallel configurations must be taken into account.     

A new method of strength calculation and lifetime prediction of pipe bends operating in the creep range

An easy to use method for an approximate creep life prediction for pipe bends was developed within a recent R & D-project in Germany. The new algorithm is based on a Finite-Element parameter study comprising approximately 200 pipe bends. The creep behaviour of the materials primarily used for main steam and hot reheat piping is described using the Graham–Walles creep law. Since the new algorithm considers the time dependent out-of-roundness and stress redistribution of the pipe bend, it yields a more precise creep life prediction, compared to standard piping codes. It is possible to integrate this new calculation into existing online lifetime-monitoring-systems.     

Thermoelastic evaluation of composite laminates using digital imaging processing

The study of the variation of the curvature of non-symmetric composite laminates with temperature provides a measure of the magnitude of the thermal stresses and the mechanical behavior of the material with temperature. In the present work, an experimental method based on the pioneer use of a digital camera and image processing method is proposed to perform such measurements. Taking advantage of the method and by comparing experimental and CLT, extended-CLT and FEM simulation results, an evaluation of the residual stresses is described and an approach providing more precise determination of the residual thermal stresses in non-symmetric laminates is proposed.     

Evaluation of a low-rate DoS attack against iterative servers

This paper presents a low-rate DoS attack that could be launched against iterative servers. Such an attack takes advantage of the vulnerability consisting in the possibility of forecasting the instant at which an iterative server will generate a response to a client request. This knowledge could allow a potential intruder to overflow application buffers with relatively low-rate traffic to the server, thus avoiding the usual DoS IDS detection techniques. Besides the fundamentals of the attack, the authors also introduce a mathematical model for evaluating the efficiency of this kind of attack. The evaluation is contrasted with both simulated and real implementations. Some variants of the attack are also studied. The overall results derived from this work show how the proposed low-rate DoS attack could cause an important negative impact on the performance of iterative servers.     

Optimizing random walk search algorithms in P2P networks

In this paper we develop a model for random walk-based search mechanisms in unstructured P2P networks. This model is used to obtain analytical expressions for the performance metrics of random walk search in terms of the popularity of the resource being searched for and the random walk parameters. We propose an equation-based adaptive search mechanism that uses an estimate of the popularity of a resource in order to choose the parameters of random walk such that a targeted performance level is achieved by the search. We also propose a low-overhead method for maintaining an estimate of popularity that utilizes feedback (or lack there-off) obtained from previous searches. Simulation results show that the performance of the equation-based adaptive search is significantly better than the non-adaptive random walk and other straight-forward adaptive mechanisms.     

基于图像处理技术的瞳孔和角膜反射中心提取算法

为了提高瞳孔中心的实时提取精度和抗干扰能力,利用基于瞳孔-角膜跟踪法原理和图像处理的眼动跟踪技术,实现瞳孔和角膜反射中心的精确提取.首先在红外光源条件下,用摄像机捕获人眼图像,通过图像自适应二值化阈值确定图像处理区域,以减小处理时间;其次,利用高低2次二值化阈值提取角膜反射中心;然后求取自适应最佳阈值确定瞳孔位置和大小;最后用梯度法提取瞳孔轮廓特征点,并用椭圆拟合瞳孔的方法确定瞳孔中心.实验结果表明,该算法在保证瞳孔和角膜反射中心提取的准确性和稳定性的同时,能满足实时处理要求.