Comparison of quantification strategies for one-point standard addition calibration: The heteroscedastic case

Two quantification strategies for one-point standard addition calibration have been compared mathematically. One strategy involved the extrapolation of measurement points to their intercept with the x-axis to determine the analyte content in the unknown sample, and the other strategy is based upon direct calculation of the analyte content in the unknown sample using the instrumental responses obtained during measurement. The cases of both conventional standard addition calibration (C-SAC) and sequential standard addition calibration (S-SAC) have been considered. The heteroscedastic situation has been considered, where the relative precision of instrumental responses is constant.     

A SIMPLIFIED AES ALGORITHM AND ITS LINEAR AND DIFFERENTIAL CRYPTANALYSES

In this paper, we describe a simplified version of the Advanced Encryption Standard algorithm. This version can be used in the classroom for explaining the Advanced Encryption Standard. After presentation of the simplified version, it is easier for students to understand the real version. This simplified version has the advantage that examples can be worked by hand. We also describe attacks on this version using both linear and differential cryptanalysis. These too can be used in the classroom as a way of explaining those kinds of attacks.     

Key factors determining the energy rating of existing English houses

In the UK, the Standard Assessment Procedure (SAP) is used to rate the energy performance of existing dwellings whenever they are let or sold. This study investigates which of the inputs to SAP account for the most variance in energy rating across existing gas central heated houses in England. Data from the English Housing Survey (EHS) 2009 are used to generate a representative set of dwellings and variance-based global sensitivity analysis is then applied to assess each input's contribution to the variance in the calculated ratings. It is demonstrated that heating system efficiency, external wall U-value and dwelling geometry account for 75% of the variance of the energy rating of gas central heated houses in England. This suggests that improving heating system efficiencies and wall U-values of the worst performing dwellings will go a long way towards improving their energy rating and potentially reducing their energy consumption. It is also demonstrated that dwelling geometry has a much bigger influence on the calculated carbon emissions (accounting for 80% of the variance) than it does on the SAP energy rating (accounting for 30%), meaning that significant improvements in energy rating might not be accompanied by significant reductions in carbon emissions.     

Optical and thermal characterization procedure for a variable geometry concentrator: A standard approach

Concentrating solar collectors are mentioned in the International Standards, but the general testing methods for solar collectors mentioned cannot easily be applied to such unusual collector designs. In this study, the best optical and thermal model for a variable geometry solar concentrator has been investigated. In the particular case of a collector with a fixed mirror concentrator, the relative position of the receiver with respect to the reflector is not constant during the day, and this variable geometry is not taken into account in the current testing Standards. An optical characterization of the prototype using a ray-tracing program has been performed, and the results have been used as an initial hypothesis to define two thermal models adapted from the European Standard. Those two different models have been compared. The optical results obtained from experiments have been compared to ray-tracing simulation results, and they have been found to be quite similar, considering the measurement uncertainties. This validation procedure of the optical simulation could be an important point to be taken into account in a future Standard revision for variable geometry collector types for which the normal incidence is not easy to obtain.     

GB5226.1-2008新版国家强制性标准综述

针对新版GB5226.1-2008国家强制性标准,本文介绍了该标准的基本情况、制修订背景、主要差异等方面内容,并讨论了标准的关键问题和使用指南等。     

A review of the accessibility of ACT COVID-19 information portals

Accessibility of public health websites allows important information to reach as many audiences as possible. This is vital during a public health crisis such as the current COVID-19 pandemic. This paper reviews public health information portals provided by the Australian Capital Territory local government against the Web Content Accessibility Guidelines.     

Porous ceramics with tailored pore size and morphology as substrates for coral larval settlement

The growing demand for stony corals as ornamental aquarium animals requires defined aquacultural breeding strategies. For the sexual propagation of corals, material substrates are needed, that attract larvae and support their settlement and development. In this study, five types of highly porous ceramic materials were developed following the example of coral skeleton. The applicability of these settlement substrates was tested using larvae of the stony coral Pocillopora damicornis. Partial sintering of pressed clay pellets, freeze casting of clay and alumina-mullite based slurries and direct foaming of high alkane phase emulsified suspensions (HAPES) using alumina were employed. By the addition of mm-sized spherical polystyrene beads as sacrificial templates during freeze casting (alumina-mullite), superficial pores in the size of the larvae were created. The inorganic substrates featured open porosities between 35% (pressed clay) and 83% (foamed alumina), pore sizes ranging from nm to mm-scale and pore morphologies dominated by interparticle porosity (pressed), lamellar pores (freeze casting) and cellular pore types (direct foaming). The ceramic substrates were incubated in artificial sea water for 3 months to induce necessary biofilm formation and algae growth. Afterwards, individual substrates were exposed to 5 coral larvae, and their settlement behavior was monitored over 14 days. At the end of this period, all ceramic materials were successfully accepted as settlement substrates, with a mean settlement rate of 46.2%, and no significant differences between the substrate types. On samples with large surface superficial pores, a significantly reduced survival of settled larvae (79%) compared to the other porous materials (93–98%) was determined, suggesting a non-ideal surface topography. While alumina foam samples (HAPES) exhibit the most promising results in terms of settlement and survival of larvae, clay-based substrates provide a more economic solution for the sexual propagation of corals in aquaculture.     

电力变压器IEC国际标准最新进展

以电力变压器专业相关的国际标准为主线,提供了已发布实施的和正在制、修订标准的相关信息,重点介绍了IEC/TC 14各工作组目前正在开展的相关标准制、修订工作,同时给出了下一步将要开展的标准制、修订计划项目。     

基于改进KNN算法的AVS到H.264/AVC 快速转码方法

尽管音视频编码标准(Audio and Video Coding Standard,AVS)的编码性能可以与H.264相媲美,但是H.264的应用范围更加广泛,因此视频由AVS标准转码成H.264标准具有很大的应用前景.目前,主流的转码方法是将AVS的分块模式与H.264的分块模式映射的方式降低转码复杂度,但是技术之间的差异导致这两种标准之间的分块模式并不是一一映射的关系,因此会导致编码效率大幅度降低.提出一种基于改进KNN(K最邻近节点)算法的AVS到H.264/AVC快速转码方法.充分利用了AVS码流中的各种信息,通过改进的KNN算法建立了中间信息和H.264分块模式之间的映射模型.根据AVS中运动矢量信息的差异自适应确定H.264可能的分块模式,实验结果表明上述问题得到有效解决,该算法在保证H.264编码效率的前提下大幅降低了转码复杂度.