Effect of Ni<Superscript>2+</Superscript>, V<Superscript>4+</Superscript> and Mo<Superscript>6+</Superscript> concentration on iron oxidation by <Emphasis Type="Italic">Acidithiobacillus ferrooxidans</Emphasis>

The ferrous oxidation ability of Acidithiobacillus ferrooxidans was studied in the presence of Ni²⁺, V⁴⁺ and Mo⁶⁺ in 9 K media in order to implement the culture in the bioleaching of spent catalyst. The rate of iron oxidation decreased with increasing concentration of metal ions, but the rate of inhibition was metal-ion dependent. The tolerance limit was critical at a concentration of 25 g/L Ni²⁺, 5 g/L V⁴⁺ and 0.03 g/L Mo⁶⁺. The growth rate of microorganisms was negligible at concentrations of 6 g/L V⁴⁺ and 0.04 g/L Mo⁶⁺. Levels and degree of toxicity of these ions have been quantified in terms of a toxicity index (TI). The toxicity order of metal ions was found to be Mo⁶⁺>V⁴⁺>Ni²⁺. The significance and relevance of multi-metal ion tolerance in Acidithiobacillus ferrooxidans has been highlighted with respect to bioleaching of spent refinery catalyst.     

Thermal perceptions,general adaptation methods and occupant's idea about the trade-off between thermal comfort and energy saving in hot–humid regions

A field study conducted in workplaces and residences in Taiwan is carried out to clarify two questions in detail: (1) do people in the tropical climate regions demonstrate a correlation between thermal sensation and thermal dissatisfaction the same as the PMV–PPD formula in the ISO 7730; and (2) does the difference in opportunities to choose from a variety of methods to achieve thermal comfort affects thermal perceptions of occupants? A new predicted formula of percentage of dissatisfied (PD) relating to mean thermal sensation votes (TSVs) is proposed for hot and humid regions. Besides an increase in minimum rate of dissatisfied from 5% to 9%, a shift of the TSV with minimum PD to the cool side of sensation scale is suggested by the new proposed formula. It also reveals that the limits of TSV corresponding to 80% acceptability for hot and humid regions are −1.45 and +0.65 rather than −0.85 and +0.85 suggested by ISO 7730. It is revealed in the findings that the effectiveness, availability and cost of a thermal adaptation method can affect the interviewees' thermal adaptation behaviour. According to the discussion of interviewees' idea about the trade-off between thermal comfort and energy saving, it is found that an energy-saving approach at the cost of sacrificing occupant's thermal comfort is difficult to set into action, but those ensure the occupant's comfort are more acceptable and can be easily popularized.     

A new time-frequency transform for non-stationary signals with any nonlinear instantaneous phase

A new generic adaptive time-frequency transform based on the Wigner distribution is proposed for amplitude estimation of transient signals with any nonlinear non-polynomial variation of the instantaneous frequency. It is for use in situations where independent synchronous measurements of the instantaneous frequency are available. It shows that the new transform tracks the instantaneous frequency and estimates signal amplitude without errors along the curve of the instantaneous frequency. The paper also applies the new transform to signals with the non-linear sinusoidal and exponential variations in the instantaneous phase and determines formulae for transform in these cases. The paper compares the new transform with the Wigner distribution in several cases and demonstrates that the new transform is more effective at amplitude estimation of signals with nonlinear variation of the instantaneous frequency. New analytic formulae are obtained for the new transform and the Wigner distribution in both the sinusoidal and the exponential cases. An analytic formula is obtained which relates the new transform to the Wigner distribution in the sinusoidal case. This formula is inverted to obtain a previously unknown formula for the Wigner distribution of any signal. It is shown that the new transform could be used for adaptive processing of transient signals with instantaneous frequency variations. The paper studies the performance of the new transform with no adaptation, partial adaptation and complete adaptation.

On Two‐Stage Estimation of the Spectral Density with Assigned Risk in Presence of Missing Data

Estimation with assigned risk is a classical statistical problem, and the theory is well developed for the case of directly observed (no missing) data. In this article a more complicated problem of estimation of the spectral density in presence of missing data is considered. First, the corresponding theory of sequential estimation with minimal expected stopping time is developed. Then it is shown that a two‐stage estimator may be used and it yields the minimal stopping time. Sample size of the first stage may be deterministic and in order smaller than a minimal stopping time, and then the first stage defines the size of the second stage. Furthermore, the estimator adapts to unknown smoothness of an underlying spectral density and to an underlying missing mechanism.     

Prophages domesticated by bacteria promote the adaptability of bacterial cells

Prophages are temperate phages integrated into the host bacterial genome. They play an important role in the adaptation and the pathogenicity of bacteria, especially pathogenic bacteria. In this review, we described the distribution of prophages in different hosts and different environments, and focused on the significance of prophages. At the singlecell level, prophages can help the host adapt to harsh external environments by directly carrying virulence genes, encoding regulatory factors and activating lysogeny. At the population level, prophages can influence the overall evolutionary direction and ecological function of the host bacterial community. This review will help us understand the important role of prophages as unique organisms in individual bacteria and microbial populations.     

SocioTelematics: Harnessing social interaction-relationships in developing automotive applications

In a cooperative convoy, a vehicle interacts with other vehicles, service providers and infrastructure systems to make the travel safe and convenient. Through these interactions a vehicle can share its domain-specific information–acquired from service providers and infrastructure–with other vehicles in the convoy. Such interactions are subject to defined agreements and constraints between the entities (i.e., vehicle to vehicle, vehicle to service provider, and so on), which we refer as (social) interaction-relationships. Such relationships, however, may need to adapt with the changes of requirements. Also a driver may want to automate certain interactions to reduce distraction during driving. A cooperative convoy telematics system should support collaboration (i.e., allow drivers to share specific travel information) and coordination (i.e., allow drivers to automate interactions), and be able to adapt to cope with the changes of requirements.In this paper, we address these issues and demonstrate how our social interaction-relationships modelling technique can be exploited to develop a telematics system, called SocioTelematics, providing such functionalities. This system allows collaboration and coordination preferences explicitly specified and updated to cope with the changes. In particular, our service oriented implementation enhances adaptability of the system, making it easily deployable and changeable. We have implemented a prototype system based on a client–server architecture where the client application is developed for Android and the server is running on the Amazon cloud. The system’s performance and resource consumption were quantified using real life experiments that show the feasibility of our approach.     

Unsupervised Domain Adaptation Learning Algorithm for RGB-D Stairway Recognition

Detection and recognition of a stairway as upstairs, downstairs and negative (e.g., ladder, level ground) are the fundamentals of assisting the visually impaired to travel independently in unfamiliar environments. Previous studies have focused on using massive amounts of RGB-D scene data to train traditional machine learning (ML)-based models to detect and recognize stationary stairway and escalator stairway separately. Nevertheless, none of them consider jointly training these two similar but different datasets to achieve better performance. This paper applies an adversarial learning algorithm on the indicated unsupervised domain adaptation scenario to transfer knowledge learned from the labeled RGB-D escalator stairway dataset to the unlabeled RGB-D stationary dataset. By utilizing the developed method, a feedforward convolutional neural network (CNN)-based feature extractor with five convolution layers can achieve 100% classification accuracy on testing the labeled escalator stairway data distributions and 80.6% classification accuracy on testing the unlabeled stationary data distributions. The success of the developed approach is demonstrated for classifying stairway on these two domains with a limited amount of data. To further demonstrate the effectiveness of the proposed method, the same CNN model is evaluated without domain adaptation and the results are compared with those of the presented architecture.     

基于模糊矩阵的大数据自适应迁移融合仿真

大数据冗余信息过多,数据迁移融合过程中会出现大量损耗,获取数据信息结果的准确率低。针对上述问题,提出基于模糊矩阵的大数据自适应迁移融合方法。构建模糊矩阵模型,根据构建的模糊矩阵求出其隶属度;通过迭代计算求出细分模糊矩阵边长,以求出的细分模糊矩阵边长为筛选标准,去除数据中的冗余部分,提高数据精度的同时减少后续运算量。在此基础上利用数据自适应度值来选择数据最优迁移路径,并根据数据相关性节点的聚合度完成融合。仿真结果证明,所提方法有效去除冗余数据,降低了数据迁移融合能耗,能够大幅提高大数据融合时的准确性和效率。     

基于子块分割的自适应式全盲图像水印算法

为了提高水印的鲁棒性,文中提出了一种基于子块分割的自适应全盲水印算法ABWASS。在嵌入水印时,该算法根据宿主特征矩阵嵌入自适应调整后的水印图像,并使用改进的两阶段DWT方法在LH2子带中融入水印图像的关键信息,从而得到含双重水印的图像;提取水印时,首先分离水印分块方式等关键信息,并通过DCT变换获得特征矩阵,进而提取水印图像。由于该方法在获得含有水印的图像时,根据宿主图像对水印进行了微调,并嵌入了原始水印尺寸,因此在提取过程可以实现全盲。实验结果表明,较已有方法,所提算法能够很好地抵抗多数常规攻击和几何攻击,并且在抵抗混合攻击上其性能均得到了提高,最大提升了2.7%;同时,其还具备较好的水印隐蔽性和实用性。