Gaussian Process Regression for Estimating EM Ducting Within the Marine Atmospheric Boundary Layer

We show that Gaussian process regression (GPR) can be used to infer the electromagnetic (EM) duct height within the marine atmospheric boundary layer (MABL) from sparsely sampled propagation factors within the context of bistatic radars. We use GPR to calculate the posterior predictive distribution on the labels (i.e. duct height) from both noise-free and noise-contaminated array of propagation factors. For duct height inference from noise-contaminated propagation factors, we compare a naive approach, utilizing one random sample from the input distribution (i.e. disregarding the input noise), with an inverse-variance weighted approach, utilizing a few random samples to estimate the true predictive distribution. The resulting posterior predictive distributions from these two approaches are compared to a "ground truth" distribution, which is approximated using a large number of Monte-Carlo samples. The ability of GPR to yield accurate and fast duct height predictions using a few training examples indicates the suitability of the proposed method for real-time applications.Comment: 15 pages, 6 figure

Characterizing Evaporation Ducts Within the Marine Atmospheric Boundary Layer Using Artificial Neural Networks

We apply a multilayer perceptron machine learning (ML) regression approach to infer electromagnetic (EM) duct heights within the marine atmospheric boundary layer (MABL) using sparsely sampled EM propagation data obtained within a bistatic context. This paper explains the rationale behind the selection of the ML network architecture, along with other model hyperparameters, in an effort to demystify the process of arriving at a useful ML model. The resulting speed of our ML predictions of EM duct heights, using sparse data measurements within MABL, indicates the suitability of the proposed method for real-time applications.Comment: 13 pages, 7 figure

An exploratory study of residents' perception of place image: the case of Kavala

Studies on place image have predominantly focused on the tourists’ destination image and have given limited attention to other stakeholders’ perspectives. This study aims to address this gap by focusing on the notion of residents’ place image, whereby it reviews existing literature on residents’ place image in terms of whether common attributes can be identified, and examines the role of community-focused attributes in its measurement. Data collected from a sample of 481 Kavala residents (Greece) were subjected to exploratory and confirmatory factor analysis. The study reveals that the existing measurement tools have typically emphasized destination-focused attributes and neglected community-focused attributes. This study contributes to the residents’ place image research by proposing a more holistic measurement, which consisted of four dimensions: physical appearance, community services, social environment, and entertainment opportunities. The study also offers practical insights for developing and promoting a tourist place while simultaneously enhancing its residents’ quality of life

Residents' place image: a meaningful psychographic variable for tourism segmentation?

While there has been a considerable body of research on tourists’ place image, there remains limited attention on residents’ place image, specifically, in relation to its segmentation utility. This study seeks to address this oversight by a) clustering the local residents based on the image held of a tourism place, and b) exploring the extent to which the identified image-based resident clusters share similar (dissimilar) demographic characteristics and attitude towards tourism development. Empirical analysis was based on a sample of 481 residents of a Greek city. The findings support the utility of residents’ place image as a psychographic segmentation variable revealing the existence of three distinct resident groups - termed “Nature Loving”, “Apathetic” and “Advocate.” Results also suggest that these resident groups exhibit dissimilar demographic characteristics and dissimilar attitude towards tourism. In comparison with other segments, the Apathetic exhibits the least favourable image and the least supportive attitude towards tourism

Computer animation data management: Review of evolution phases and emerging issues

The computer animation industry has been booming and prospering in recent thirty years. One of the significant changes faced by this industry is the evolution of computer-animation data and, yet, extant literature has offered very little insights into the evolution process and management issues pertinent to computer-animation data. Hence, many questions have surfaced in the extant literature of computer-animation data management. For example, to what extent has the data content expanded in terms of quantity and quality? To what extent has the information technology used to store and process the data changed? To what extent have the user and the community groups diversified in terms of their nature and number? Knowledge pertaining to these issues can provide new research directions to academics and also insights to practitioners for more effective and innovative management of computer-animation data. This conceptual paper, therefore, takes the pioneering step to address these issues by proposing four factors prudent for examining the evolution phases associated with computer-animation data management: technology, content, users, and community. Next, this paper presents a conceptual framework illustrating the inter-dependent relationships between these four factors together with associated theoretical and managerial issues. This paper, albeit limited by its conceptual nature, advances the extant literature of computer animation, information system, and open-product model

Nondestructive Measurement of Orbital Angular Momentum for an Electron Beam

Free electrons with a helical phase front, referred to as "twisted" electrons, possess an orbital angular momentum (OAM) and, hence, a quantized magnetic dipole moment along their propagation direction. This intrinsic magnetic moment can be used to probe material properties. Twisted electrons thus have numerous potential applications in materials science. Measuring this quantity often relies on a series of projective measurements that subsequently change the OAM carried by the electrons. In this Letter, we propose a nondestructive way of measuring an electron beam's OAM through the interaction of this associated magnetic dipole with a conductive loop. Such an interaction results in the generation of induced currents within the loop, which are found to be directly proportional to the electron's OAM value. Moreover, the electron experiences no OAM variations and only minimal energy losses upon the measurement, and, hence, the nondestructive nature of the proposed technique.Comment: 5 pages, 3 figures, and supplemental material that is comprised of text and 4 figure

Cordyceps cicadae induces G2/M cell cycle arrest in MHCC97H human hepatocellular carcinoma cells: a proteomic study

published_or_final_versio

Physical activity for children in special school environment

&nbsp;Key Messages1. We assessed children&rsquo;s physical&nbsp;activity (PA) in structured (physical&nbsp;education) and unstructured&nbsp;(recess, lunch, before and after&nbsp;school) periods in special schools&nbsp;and examined its association&nbsp;with modifiable area contextual&nbsp;characteristics.2. Children with disabilities were not&nbsp;highly active, but were more active&nbsp;during recess and lunch periods&nbsp;than at other times including&nbsp;physical education classes.3. Areas were often not accessible&nbsp;during unstructured settings.&nbsp;Children were more active in areas&nbsp;when supervision and organised&nbsp;activities were provided.4. Providing an interactive game&nbsp;during free play did not significantly&nbsp;increase group&rsquo;s PA.5. Children&rsquo;s PA accrual is influenced&nbsp;by contextual characteristics of&nbsp;the school environment. There is a&nbsp;need to make areas more accessible&nbsp;and to use social marketing and&nbsp;programming to attract more users.&nbsp;School and health professionalsshould modify contextual&nbsp;characteristics by providing more&nbsp;direct supervision and organised&nbsp;activities during free play.</div