Do you know what your license allows?

Before you push a key to load a program and display it on your monitor, ask yourself this question: “Do I have the power to use this program?” Using software requires power-not physical or electrical power-but the legal power of authorized use. If you are not the program's author or owner, you can only obtain this power through a license-a legal document that states your rights regarding use of the program. This may include the right to use or operate the program as an end user; modify the program through deletions, additions or enhancements as a value-added reseller or original equipment manufacturer; or transfer the program to another as an aggregator, distributor or retailer. If you do not have the appropriate legal power, then your conduct is illegal. If you know that you do not have the appropriate legal power, then your conduct, which amounts to software piracy, is criminal     

Information limit on the spatial integration of local orientation signals

Channel-based models of human spatial vision require that the output of spatial filters be pooled across space. This pooling yields global estimates of local feature attributes such as orientation that are useful in situations in which that attribute may be locally variable, as is the case for visual texture. The spatial characteristics of orientation summation are considered in the study. By assessing the effect of orientation variability on observers' ability to estimate the mean orientation of spatially unstructured textures, one can determine both the internal noise on each orientation sample and the number of samples being pooled. By a combination of fixing and covarying the size of textured regions and the number of elements constituting them, one can then assess the effects of the texture's size, density, and numerosity (the number of elements present) on the internal noise and the sampling density. Results indicate that internal noise shows a primary dependence on texture density but that, counterintuitively, subjects rely on a sample size approximately equal to a fixed power of the number of samples present, regardless of their spatial arrangement. Orientation pooling is entirely flexible with respect to the position of input features.     

DRYING RATE AND TEMPERATURE PROFILE FOR SUPERHEATED STEAM VACUUM DRYING AND MOIST AIR DRYING OF SOFTWOOD LUMBER

Abstract

Two charges of green radiata pine sapwood lumber were dried, either using superheated steam under vacuum (90°C, 0.2 bar abs.) or conventionally using hot moist air (90/60°C). Due to low density of the drying medium under vacuum, the circulation velocity used was 10 m/s for superheated steam drying and 5.0 m/s for moist air drying, and in both cases, the flow was unidirectional. In drying, stack drying rate and wood temperatures were measured to examine the differences between the superheated steam drying and drying using hot moist air.

The experimental results have shown that the stack edge board in superheated steam drying dried faster than in the hot moist air drying. Once again due to the low density of the steam under vacuum, a prolonged maximum temperature drop across load (TDAL) was observed in the superheated steam drying, however, the whole stack dried slower and the final moisture content distribution was more variable than for conventional hot moist air drying. Wood temperatures in superheated steam drying were lower.     

Distributed optical fibre Raman temperature sensor using a semiconductor light source and detector

The letter reports on the first experimental measurements of the temperature distribution along silica-based optical fibres using a semiconductor laser source and an avalanche photodiode detector. Previous results by the same authors demonstrated the first use of the Raman scattering technique, but used a less practical ion laser source and a photomultiplier detector.     

DRYING RATE AND TEMPERATURE PROFILE FOR SUPERHEATED STEAM VACUUM DRYING AND MOIST AIR DRYING OF SOFTWOOD LUMBER

Two charges of green radiata pine sapwood lumber were dried, either using superheated steam under vacuum (90°C, 0.2 bar abs.) or conventionally using hot moist air (90/60°C). Due to low density of the drying medium under vacuum, the circulation velocity used was 10 m/s for superheated steam drying and 5.0 m/s for moist air drying, and in both cases, the flow was unidirectional. In drying, stack drying rate and wood temperatures were measured to examine the differences between the superheated steam drying and drying using hot moist air.

The experimental results have shown that the stack edge board in superheated steam drying dried faster than in the hot moist air drying. Once again due to the low density of the steam under vacuum, a prolonged maximum temperature drop across load (TDAL) was observed in the superheated steam drying, however, the whole stack dried slower and the final moisture content distribution was more variable than for conventional hot moist air drying. Wood temperatures in superheated steam drying were lower.     

Beat frequency measurement system for multiple dual polarization fiber DFB lasers

This paper describes the design and testing of an electronic system intended to record the beat frequency signal from up to eight serially multiplexed dual polarization fiber distributed feedback lasers. The beat frequency from each laser is first mixed down to around 70 MHz and then measured using a PC based counter system. The gate frequency and, hence, the sampling rate, is designed to be around 1 kHz, and the frequency resolution of the system is found to be equal to the gate frequency. The system has been used to measure the beat frequency variation of fiber lasers due to either rapidly varying temperature or flexing motion. Measurements made with multiple fiber laser sensors show that the crosstalk between different sensors is very low.     

Distributed grating sensors using low-coherence reflectometry

Distributed grating sensors have recently been interrogated with low-coherence reflectometry. Initial results have been enhanced using two new and versatile configurations. The first system tracks the wavelength using a closed-loop scheme, while the second system scans the distance using an open-loop approach. Arbitrary strain and temperature profiles along gratings have been examined with 300 μm spatial resolution and 5.4 μϵ/√Hz accuracy. A theoretical model of the interrogation technique is derived and the predicted performance limits are examined experimentally     

采用Tm光纤光源的甲烷气体相关光谱检测

报道了以半导体激光器泵浦掺Ｔｍ３＋光纤为光源的甲烷气体相关光谱检测系统，研究了７８８ｎｍ波长泵浦下掺Ｔｍ光纤光源的一些光谱特性，并在实验上用这种光源及系统对甲烷气体作了测量。在５．７ｃｍ长的测量腔下，系统噪声幅度对应的最小气体检测浓度为０．４７％，远低于甲烷气体的爆炸低限（５％），证明了这种光纤光源用于甲烷气体浓度测量的可行性。