Vibration-induced modulation of magnetic anisotropy in a magnetic molecule

We theoretically analyze the spectrum of a magnetic molecule when its charge and spin can couple to the molecular vibrations. More specifically, we show that the interplay between charge-vibron and spin-vibron coupling leads to a renormalization of the magnetic anisotropy parameters of the molecule. This effect is discussed for a model device consisting of an individual magnetic molecule embedded in a junction. We study the transport properties of the device and illustrate how the differential conductance is affected by the vibrationally induced renormalization of the magnetic anisotropy. Depending on the total molecular spin and the bare (intrinsic) magnetic anisotropy, the induced modulation can lead to visible shifts and crossings in the spectrum, and it can even be the cause of a transport blockade. It is therefore of particular interest to use mechanically controllable break junctions, since in such a case, the relevant coupling between the molecular spin and vibrations can be controlled via deformations of the molecule when stretching or compressing the junction.Comment: 18 pages, 7 figures, version as publishe

A proposed segmented precast concrete spherical cap: geometry, structural stability and construction

This study proposes the design and construction of a concrete spherical cap composed of uniformly-shaped precast doubly-curved panels based on spherical division techniques. A numerical structural analysis is conducted to study the failure behavior of the segmented structure and the capacity of the joints by using finite element modeling techniques to model the concrete material behavior, boundary conditions and intermediate joints of the precast panels. An experimental analysis is conducted to verify the capacity of the structure and the reliability of the modeling techniques, and to study the feasibility of the proposed panel prefabrication and assembly method. The results of this study demonstrate that the proposed precast system and connection design perform efficiently when compared to the monolithically-cast counterpart, particularly under uniform loading conditions. Additional insights on the properties and solution parameters of finite element modelling of concrete shell structures are presented based on the structural analysis of this work. The study concludes the ability of the proposed geometric design and construction method to enhance the prefabrication and construction efficiency with little effect on the structural capacity within the context of the selected geometry and conducted load tests, and recommends further parameters to study for design and construction optimization

Social media policy in Egypt: case studies of three ministries

The use of social media tools in Egyptian government, while still relatively new, is gaining acceptance at all levels of government which is widely reflected in the number of social media pages for Egyptian ministries. By logging on Facebook or Twitter you can follow most of Egyptian ministries updated releases and news. Yet, it is still not clear how Egyptian government is regulating public employees\u27 use of such interactive platforms. The purpose of this study is to answer the main research questions: What are the key elements of a social media policy? How Egyptian ministries are using social media? How Egyptian ministries are managing their social media pages? What challenges are Egyptian ministries encountering as they use social media? To achieve this purpose, the methodology adopted in this study include a review of literature, analysis of existing social media policies in different countries, and interviews with social media officials in a purposive non- random sample of Egyptian Ministries to examine their policies regarding social media use. The sample includes the Ministry of Finance, the Ministry of Planning, Monitoring and Administrative Reform, and the Ministry of Supply and Internal Trade, as they represent Egyptian ministries from different levels; sovereign, economic and service ministries. The study findings indicate that the Egyptian government lacks having social media policies that regulate the use of social media. After interviewing social media officials in different Egyptian ministries, it has been concluded that there are no concrete written policies that monitor and regulate public employees\u27 usage of social media. Finally, this thesis recommends a social media policy guide for Egyptian government that will assist in setting guidelines that regulate their use of social media

Thermal comfort adaptation in outdoor places

The level of international migration has been growing in the last decades creating a plurality of cultures and inspiring a multicultural nature in global cities (O\u27Byrne, 1997; Short and Kim, 1999; Hawkins, 2006). This created new challenges in urban planning or the management of the coexistence of different people that are having different characteristics shaping their unique identity and needs in shared places. Being the urban stages where the social interactions happen, public places are considered important parts of cities (Thompson, 2002; Varna, 2009). These places can contribute to enhance the quality of life within cities, or contrarily increase isolation and social exclusion (Lo et al.; 2003). As agreed by researchers the users’ state of comfort gives a good indication for how successful is the public outdoor places (Rosheidat et al.; 2008; Kwong et al.; 2009; Aljawabra and Nikolopoulou, 2010). In order to create a successful open space usable by all members of a community, urban designers need to satisfy their thermal comfort needs in its wider meaning according to a variety of users (Knez and Thorsson, 2006; Thorsson et al.; 2007). While assessing the thermal comfort, in addition to the strong influence of the microclimatic parameters, the term thermal adaptation seems to becoming increasingly important. The thermal comfort adaption is then a considerable issue in design guidelines of outdoor environments (Nikolopoulou and Steemers, 2003). The main aim of the research is to examine the influence of thermal adaptation and environmental attitude on participants’ thermal requirements in outdoor public places. It focuses on understanding the effect of adaptation on the thermal comfort perception of immigrants. The research methodology of the research is provided through quantitative analysis of a case study. The findings of thermal comfort investigations could be applied into improving the quality of urban areas in order to increase the outdoor activities of citizens and use of outdoor places

Effect of slot type identification on frame length optimization

In dense radio frequency identification (RFID) systems, reducing reading times is crucial. For tag anti-collision management, most RFID systems rely on frame slotted ALOHA (FSA). The most common method to reduce the reading time for large tag populations is optimization of the number of slots per frame. The slot duration in real RFID systems is determined by the slot type (idle, successful, or colliding). Furthermore, by detecting the strongest transponder, colliding slots can be transformed to successful slots, a phenomenon known as the capture effect. Additionally, RFID readers might be capable of identifying slot types using the physical layer which reduces the colliding slot time because at this moment the reader can immediately terminate the connection as there is no need to reply with invalid acknowledge and wait for the time-out. In this paper, we provide a novel approach for analytical estimation of the optimal frame length. Our approach yields a novel closed form equation for the frame length that takes into account durations of different slot types, the capture effect, and the probability of slot type identification. Experimental results for FM0 encoding show that our technique achieves a total reading time reduction between 5.5% and 11.3% over methods that do not take into account slot type identification. However, the reduction in reading time is maximally 9%, 6%, and 1% for Miller encoding scheme with M = 2, 4, and 8, respectively

Early Eocene Nummulitids from Gebel Umm Russeies, El Galala El Bahariya, Eastern Desert, Egypt

Seven larger foraminiferal species: Nummulites aff. nemkovi SCHAUB, 1966, Nummulites partschi DE LA HARPE, 1880, Nummulites bassiounii BOUKHARY & BLONDEAU, 1991, Nummulites cf. campesinus SCHAUB, 1966, Assilina aff. major HEIM, 1908, Decrouezina aegyptiaca Boukhary, 1994 and Operculina sp. are described from the Early Eocene Gebel Umm Russeies, Northern Galala, Eastern Desert, Egypt. These taxa are biostratigraphically evaluated and according to the standard shallow benthic zones, the identified biozones span SBZ 10 to SBZ 12 in the shallow benthic zones (SBZ) of SERRA-KIEL et al. (1998) which are assigned to the Late Ypresian

Using BlazePose on Spatial Temporal Graph Convolutional Networks for Action Recognition

The ever-growing available visual data (i.e., uploaded videos and pictures by internet users) has attracted the research community’s attention in the computer vision field. Therefore, finding efficient solutions to extract knowledge from these sources is imperative. Recently, the BlazePose system has been released for skeleton extraction from images oriented to mobile devices. With this skeleton graph representation in place, a Spatial-Temporal Graph Convolutional Network can be implemented to predict the action. We hypothesize that just by changing the skeleton input data for a different set of joints that offers more information about the action of interest, it is possible to increase the performance of the Spatial-Temporal Graph Convolutional Network for HAR tasks. Hence, in this study, we present the first implementation of the BlazePose skeleton topology upon this architecture for action recognition. Moreover, we propose the Enhanced-BlazePose topology that can achieve better results than its predecessor. Additionally, we propose different skeleton detection thresholds that can improve the accuracy performance even further. We reached a top-1 accuracy performance of 40.1% on the Kinetics dataset. For the NTU-RGB+D dataset, we achieved 87.59% and 92.1% accuracy for Cross-Subject and Cross-View evaluation criteria, respectively

Electromotive force in driven topological quantum circuits

Time-dependent control of superconducting quantum circuits is a prerequisite for building scalable quantum hardware. The quantum description of these circuits is complicated due to the electromotive force (emf) induced by time-varying magnetic fields. Here, we examine how the emf modifies the fractional Josephson effect. We show that a time-varying flux introduces a new term that depends on the geometry of both the circuit and the applied magnetic field. This term can be probed via current and charge measurements in closed-loop and open-circuit geometries. Our results refine the current understanding of how to properly describe time-dependent control of topological quantum circuits.Comment: 13 pages, 5 figures; added appendix C, added acknowledgments, improved overall flow, results and figures unchange

Advanced Guided Whale Optimization Algorithm for Feature Selection in BlazePose Action Recognition

The BlazePose, which models human body skeletons as spatiotemporal graphs, has achieved fantastic performance in skeleton-based action identification. Skeleton extraction from photos for mobile devices has been made possible by the BlazePose system. A Spatial-Temporal Graph Convolutional Network (STGCN) can then forecast the actions. The Spatial-Temporal Graph Convolutional Network (STGCN) can be improved by simply replacing the skeleton input data with a different set of joints that provide more information about the activity of interest. On the other hand, existing approaches require the user to manually set the graph’s topology and then fix it across all input layers and samples. This research shows how to use the Statistical Fractal Search (SFS)-Guided whale optimization algorithm (GWOA). To get the best solution for the GWOA, we adopt the SFS diffusion algorithm, which uses the random walk with a Gaussian distribution method common to growing systems. Continuous values are transformed into binary to apply to the feature-selection problem in conjunction with the BlazePose skeletal topology and stochastic fractal search to construct a novel implementation of the BlazePose topology for action recognition. In our experiments, we employed the Kinetics and the NTU-RGB+D datasets. The achieved actiona accuracy in the X-View is 93.14% and in the X-Sub is 96.74%. In addition, the proposed model performs better in numerous statistical tests such as the Analysis of Variance (ANOVA), Wilcoxon signed-rank test, histogram, and times analysis