Vibrations of an aramid anchor cable subjected to turbulent wind

The vibration response of an initially pre-stressed anchor cable made of parallel-lay aramid fibres excited by a measured and artificially simulated spatial turbulent wind field is presented in the paper. Results of the analyses of in situ measured wind records are described. For selected data set statistical characteristics and power spectral density functions of the measured wind velocity components are calculated. The wind stochastic velocity fluctuation is modelled as a one-variate bi-dimensional random field. Cross-power spectral density functions, at different point locations are introduced. The combination of the weighted amplitude wave superposition method (WAWS) with the Shinozuka–Deodatis method is used for the analyzed problem. A time-dependent behaviour of the synthetic cable is investigated which is subjected to turbulent wind with large expected oscillations that arise as a result of slackening due to the relaxation effects. A nonlinear transient dynamic analysis is used in conjunction with the finite element method to determine the dynamic response of the cable subjected to turbulent wind at its initially prestressed state and in the selected times after the relaxation effect. The constitutive equation of the relaxation of the aramid cable follows an experimentally obtained law of the logarithmic type. To monitor the dependences of the individual quantities of cable vibration in the phase space, attractors and Poincaré maps are created by sampling the cable’s displacement and velocity at periods of relevant frequencies. Interesting findings based on the response of the cable with rheological properties to turbulent wind are presented.     

Exploratory analysis of excitation-emission matrix fluorescence spectra with self-organizing maps—A tutorial

Large datasets are common in chemical and environmental engineering applications and tools for their analysis are in great demand. Here, the outputs of a series of fluorescence spectroscopy analyses are utilised to demonstrate the application of the self-organising map (SOM) technique for data analysis. Fluorescence spectroscopy is a well-established technique of organic matter fingerprinting in water. The technique can provide detailed information on the physico-chemical properties of water. However, analysis of fluorescence spectra requires the application of robust statistical and computational data pre-processing and analysis tools.This paper presents a tutorial for training engineering postgraduate researchers in the use of SOM techniques using MATLAB^®. Via a tutorial, the application of SOM to fluorescence spectra and, in particular, the characterisation of organic matter removal in water treatment, is presented. The tutorial presents a step-by-step example of the application of SOM to fluorescence data analysis and includes the source code for MATLAB^®, together with presentation and discussion of the results. With this tutorial we hope to popularise this robust pattern recognition technique for fluorescence data analysis and large data sets in general, and also to provide educational practitioners with a novel tool with which to train engineering students in SOM.     

Tribo-oxidation maps for Ti against steel

A fundamental study of wear transition regimes was carried out for a pin-on-disk sliding couple, involving titanium and steel. The sliding speed was varied from 0.38 to 1.5 m s⁻¹ and the normal load from 10 to 50 N. Wear mapping approaches have been undertaken to represent the transitions in wear modes and wear mechanisms regimes, as a function of applied normal loads and sliding speeds and for both pin and disc separately on the basis of experimental results. Dry sliding wear behaviour of steel was characterized by tribo-oxidative wear with high material transfer from the titanium. In contrast, adhesive wear was more prevalent for the titanium and oxidative wear mechanisms led to formation of non-protective films on the surface.     

Mental maps compared to actual spatial behavior using GPS data: A new method for investigating segregation in cities

This article examines the relationship between perceived territorial boundaries and actual spatial activity. The methodology used includes a combination of mental maps and interviews for examining perceptions of territorial boundaries, with tracking technology (GPS) and activity diaries to track the actual use of space. This methodology was implemented in a pilot study with a sample of 18 women living in Jerusalem, including secular Jews, ultra-orthodox Jews, and Palestinian Muslims.The study found a very strong relationship between perceived personal territory and actual spatial activity. However, while the secular Jewish women appeared to be completely segregated within their territory, the ultra-orthodox Jewish women and the Palestinian Muslim women were both very active within the secular Jewish territory, but avoided each other’s territories. The analysis of mental maps and actual spatial patterns of residential daily activities challenges prevailing notions about the spatial structure of Jerusalem and the internal power relations between the populations that inhabit it. More generally, it provides a new methodological approach for investigating segregation in cities.     

Concept maps as the first step in an ontology construction method

A method is proposed to be used as the first step in the ontology acquisition process. This method is based on the use of concept maps as a means of expression for the expert, followed by an application that assists the expert in detailing the structure of the knowledge represented in the map. This application analyses the concept map, taking into account the map topology and key words used by the expert. From this analysis a series of questions are presented to the expert that, when answered, reduce the map ambiguity and identify some common patterns in ontological representations, such as generalizations and mereologic relations. This information can be used by the knowledge engineer during further knowledge acquisition sessions or to direct the expert to a further improvement of the map. The method was tested by a group of volunteers, most of them engineers working at the aerospace sector, and the results suggest that both the use of concept mapping as well as the refining step are acceptable from the point of view of the end user, supporting the claim that this method is viable as an option to reduce some of the difficulties in large scale ontology construction.     

Measurement and analysis of thermal properties of rocks for the compilation of geothermal maps of Cyprus

Previous studies in Cyprus classified the island in the category of low enthalpy with high potentials in the usage of geothermal energy for space air-conditioning. Due to the little existing information about the underground thermal properties, an extended geological sampling has been carried out on the island. Measurements of thermal properties have been performed in the laboratory at room temperature for all the collected samples both in their dry and water-saturated state. The impact on thermal conductivity of water in samples, the mineralogical composition, and the geological age of samples have been the objectives of the current study.Laboratory results of each rock type in Cyprus are found within certain ranges for each thermo-physical property as follows. Thermal conductivity values for dry rock samples vary between 0.4 and 4.2 W m⁻¹ K⁻¹, thermal diffusivity values range between 0.3 and 1.9 × 10⁻⁶ m² s⁻¹ and specific heat capacity values range from 0.5 to 1.5 J K⁻¹ kg⁻¹. Results also show that thermal conductivity and thermal diffusivity under moisture conditions increase for most of the lythotypes. The notable exception is Gypsum (Kalavaso Formation), which exhibits higher thermal response under dry conditions.Measured thermal properties also present a difference between thermal properties of the lithologies of the Troodos Ophiolite and the Circum Troodos Sedimentary Succession in Cyprus. Mean values of thermal conductivity and thermal diffusivity for dry samples and water-saturated samples have higher values for the lithologies of the Troodos Ophiolite than measured values for the lithologies of the Circum Troodos Sedimentary Succession, mostly due to their mineralogical composition.Moreover, the geological age of a lithology has been shown to affect its thermal response. Thermal conductivity of reef limestone and calcarenite rocks increases with the geological age of the lithology.In order to understand and visualize all measured data the Thermal Conductivity and the Thermal Diffusivity Maps of Cyprus have been compiled with the use of a Geographic Information System (GIS) to be available to engineers as a powerful tool for use in the design of thermal engineering systems. From the obtained maps Troodos Ophiolite can be visualized as a separate part by having the highest values.     

Rapid visualization of the potential residential cost savings from energy storage under time-of-use electric rates

Buildings feature a prominent role in electric grid loading, as they use about 75% of the total electricity generated in the United States and are main drivers of electric peak demand in the summer due to electrically driven air conditioning systems. Energy storage is a key technology that can increase energy cost savings, and add flexibility to the grid. However, cost is an important factor to consider. This study proposes a rapid approach that allows for visualization of potential cost savings by introducing energy storage as a peak load control for residential buildings in California. A combination of EnergyPlus load data generation, Matlab post-processing, and Google Fusion Tables data presentation analyses the potential cost savings when energy storage is implemented and TOU rates are applied. The study presents potential annual cost savings of $420 per home with storage capacities of 24?kWh.     

基于改进YOLOv5s的药盒钢印日期识别方法

目的 药盒的钢印日期与背景对比度低,字符轮廓不明显,识别易受环境光线干扰,对此提出一种基于机器视觉的识别方法。方法 使用改进YOLOv5s模型,首先对采集的药盒数据集进行透视变换校正,并进行数据增强。通过在模型的骨干网络中融合位置注意力机制(CA),减少冗余信息的干扰;颈部网络根据加权双向特征金字塔网络(BiFPN)引入权重,更好地平衡不同尺寸图层的特征信息;引入动态聚焦损失函数(WIoU),降低高质量样本对训练的干预,提高模型的泛化能力。结果 在自建钢印字符数据集上的实验结果表明,改进网络对药盒钢印日期识别的平均精度值达到了99.41%,比原始模型提升了2.38%,帧率为80.01帧/s。结论 改进后的YOLOv5模型对药盒钢印日期的检测精度优于原有网络,对可以满足药盒生产线的实时性要求。     

Nonlinear Dimensionality Reduction and Data Visualization： A Review

Dimensionality reduction and data visualization are useful and important processes in pattern recognition.Many techniques have been developed in the recent years.The self-organizing map (SOM) can be an efficient method for this purpose.This paper reviews recent advances in this area and related approaches such as multidimensional scaling (MDS),nonlinear PCA,principal manifolds,as well as the connections of the SOM and its recent variant,the visualization induced SOM (ViSOM),with these approaches. The SOM is shown to produce a quantized,qualitative scaling and while the ViSOM a quantitative or metric scaling and approximates principal curve/surface.The SOM can also be regarded as a generalized MDS to relate two metric spaces by forming a topological mapping between them.The relationships among various recently proposed techniques such as ViSOM,Isomap,LLE,and eigenmap are discussed and compared.