Development of New Models for Vision-Based Human Activity Recognition

Els mètodes de reconeixement d'accions permeten als sistemes intel·ligents reconèixer accions humanes en vídeos de la vida quotidiana. No obstant, molts mètodes de reconeixement d'accions donen taxes notables d’error de classificació degut a les grans variacions dins dels vídeos de la mateixa classe i als canvis en el punt de vista, l'escala i el fons. Per reduir la classificació incorrecta , proposem un nou mètode de representació de vídeo que captura l'evolució temporal de l'acció que succeeix en el vídeo, un nou mètode per a la segmentació de mans i un nou mètode per al reconeixement d'activitats humanes en imatges fixes.Los métodos de reconocimiento de acciones permiten que los sistemas inteligentes reconozcan acciones humanas en videos de la vida cotidiana. No obstante, muchos métodos de reconocimiento de acciones dan tasas notables de error de clasificación debido a las grandes variaciones dentro de los videos de la misma clase y los cambios en el punto de vista, la escala y el fondo. Para reducir la clasificación errónea, Łproponemos un nuevo método de representación de video que captura la evolución temporal de la acción que ocurre en el video completo, un nuevo método para la segmentación de manos y un nuevo método para el reconocimiento de actividades humanas en imágenes fijas.Action recognition methods enable intelligent systems to recognize human actions in daily life videos. However, many action recognition methods give noticeable misclassification rates due to the big variations within the videos of the same class, and the changes in viewpoint, scale and background. To reduce the misclassification rate, we propose a new video representation method that captures the temporal evolution of the action happening in the whole video, a new method for human hands segmentation and a new method for human activity recognition in still images

Reduction of Quantum Noise in Transmittance Estimation Using PhotoneCorrelated Beams

The accuracy of optical measurements at low light levels is limited by the quantum noise of the source and by the random nature of the interaction with the measured object. The source noise may be reduced by use of nonclassical photon-number squeezed light. This paper considers the use of two photon-correlated beams (generated, for example, by spontaneous parametric downconversion) to measure the optical transmittance of an object. The photons of each beam obey a random Poisson process, but are synchronized in time. One beam is used to probe the object while the other is used as a reference providing information on the realization of the random arrival of photons at the object. The additional information available by such measurement may be exploited to improve the accuracy of the measurement. Various estimators, including the maximum likelihood estimator, are considered and their performance is evaluated and compared with the measurement based on single-beam conventional (Poisson) source and maximally squeezed (fixed photon number) source. The performance advantage established in this paper depends on parameters such as the intensity of the source, the transmittance of the object, the quantum efficiency of the detectors, the background noise, and the degree of correlation of the photon numbers in the two beams

Nondestructive Evaluation of Loading and Fatigue Effects in Haynes® 230® Alloy

Nondestructive evaluation is a useful method for studying the effects of deformation and fatigue. In this dissertation I employed neutron and X-ray diffraction, nonlinear resonant ultrasound spectroscopy (NRUS), and infrared thermography to study the effects of deformation and fatigue on two different nickel based superalloys. The alloys studied were HAYNES 230, a solid solution strengthened alloy with 4% M6C carbides, and secondarily HASTELLOY C-2000 a similar single phase alloy. Using neutron and X-ray diffraction, the deformation behavior of HAYNES 230 was revealed to be composite-like during compression, but unusual in tension. The carbides present in this alloy do not provide strengthening in tension as would be expected or finite element modeling predicted. The carbides provide strengthening until just after the macroscopic yield strength and then they begin to debond and crack, creating a tension-compression asymmetry that is revealed clearly by in situ diffraction. HASTELLOY C-2000, a similar alloy without carbides, shows typical anisotropic load sharing between differently oriented grains. In fatigue of HAYNES 230, the hkl behavior as revealed by neutron diffraction showed that the elastic strain changes very little in tension-tension fatigue. However, in situ tension-compression studies showed large changes over the initial stages of fatigue. There was slight evidence for changes in elastic modulus as fatigue progressed. The HAYNES 230 samples studies had two distinct starting textures, measured by neutron diffraction. Some samples were texture free initially and deformed in tension and compression to fiber textures. Other samples started with a bimodal texture due to cross-rolling and incomplete annealing. The final texture of these bimodal samples is shown through modeling to be a superposition of the initial texture and typical FCC deformation mechanisms. The effect of these different textures on the macroscopic and internal-elastic stress-strain curves are shown. The texture-free samples deformed significantly more macroscopically and in internal elastic strains than the samples with the cross-rolled texture. In contrast to the relative insensitivity of neutron diffraction to the effects of tension-tension fatigue, NRUS revealed large differences between as-received and progressively fatigued samples. This showed that microcracking and void formation are the primary mechanisms responsible for fatigue damage in tension- tension fatigue. NRUS is shown to be a useful complimentary technique to neutron diffraction to evaluate fatigue damage. Finally, infrared thermography is used to show temperature changes over the course of fatigue in HASTELLOY C-2000. Four stages of temperature are shown over the course of a single fatigue test: an initial temperature rise, followed by an equilibrium region, a sharp increase of temperature at failure and, finally, a cooling back to room temperature after fracture. Both empirical and theoretical relationships between steady state temperature and fatigue life are developed and presented

Screen printed layers of cds for solar cells

It is generally accepted nowadays that a significant cost reduction in terrestrial solar cell application could be brought about by investigating alternative fabrication techniques for solar cells. It is believed that screen printing (or the so called thick film technique) is one such technique which promises a potentially low cost method for fabricating flexible, large area solar energy conversion cells. The active research on this technique started in 1976 in Japan. However, it was not until 1983, that wide interest developed when the Matsushita group in Japan reported an efficiency of 12.8% for their entirely screen printed CdS/CdTe solar cells. This was the highest reported efficiency for any thin film solar cell. However, the details of the fabrication processes of these cells were not reported and several scientific groups in the world started to explore this technique. The first published report was in 1985. In the last few years these groups have reported results on various aspects of this technique. Nevertheless there are still major parameters to be investigated. This thesis represents a concise reference for the application of the screen printing technique to solar cells. In the course of this study many new investigations have been made which supplement the previous work by other groups. Starting with a pure CdS powder with suitable grain size and distribution is a prerequisite for achieving the best morphological and electrical behaviour of screen printed layers of CdS. Careful paste mixing is of uppermost importance which can override any other parameters involved in the fabrication processes. It is essential to impose restricted sintering conditions for adequate utilization of the doping and fluxing function of the CdCl(_2) material. Standardization of the printing, preparation and sintering conditions involved in the fabrication processes were necessary to ensure reproducible CdS layers. Good quality screen printed layers were fabricated on soda lime substrates. The significance of other substrate materials for CdS preparation was also investigated and optimum substrate choice is suggested. The properties of the CdS screen printed layers were investigated by forming simple Schottky devices and more complicated heterojunction solar cells. Good rectification behaviour of the Schottky diodes was achieved. The CdS/CdTe solar cells revealed a wide spectral response. However, the photovoltaic behaviour was relatively poor largely due to the high resistivity of the CdTe part of the cell structure

Joint Attention Impairment in Autism: Clinical Picture, Rationale and Functional MRI Findings

Joint attention is a keystone in social cognitive development and a skill acquired early in life. It is the triadic coordination of attention between two people and an object or event in which they are commonly interested. Language development follows in its tracks and is dependent on this early acquired skill. Its deviation from typical development is considered one of the earliest signs of autism. Consequently, its remediation has gained intensive focus in therapy. In this review, the development of joint attention skill in initiating (IJA) and responding (RJA), and its atypical development in autism and related spectrum disorders would be discussed. This would include existing problems in pointing, sharing attention with the participant, and facial recognition; and the rationale behind these deviations as covert attention. Related fMRI findings would also be reviewed, outlining the integration between the posterior involuntary parietal and superior temporal cortices (RJA) and the anterior volitional prefrontal and orbital frontal areas (IJA) in typical development, and the long‐distance underconnectivity and local overconnectivity in autism. Several cortical regions are implicated in autism, revealing the heterogeneity of the findings, but general conclusions could be drawn

Correlation between geometrical and structural properties of mixed oxide ultrathin nanotubes and their solar water splitting performance

The objective of this study was to study the effect of Nb alloying with Ti on the photoelectrochemical performance of the resulted oxide upon anodization. In this regard, nanotubes were grown on Ti-Nb alloy via electrochemical anodization and their corresponding photocatalytic behavior was investigated and compared with those grown on an ordinary Ti substrate. After preparing and optimizing the nanotubes dimensions for the required geometrical structure, the as formed tubes were annealed at different temperatures and in air), then characterized with respect to their morphological, structural, and photoelectrochemical properties. From the morphological and structural point of view, optimized and well aligned ultra-thin wall nanotubes were successfully synthesized on the surface of Ti-Nb alloy. To the best of our knowledge, these dimensions have not been reported before. One of the challenges was that the oxide layer formed on the surface of the alloy was not precisely identified in literature, where some authors reported the formation of combination of individual oxides (TiO2 and Nb2O5), whereas, others claimed it was a mixed oxide TiNbOx. Raman and X-ray diffraction test results confirmed the formation of individual anatase and monoclinic Nb2O5 phases. Detailed XRD analysis was performed and the crystallite size as well as microstrain were calculated and found to be minimal indicating negligible effect of lattice induced tension or compression. It is worth mentioning that insignificant structural changes are favorable to maintain good electron mobility. Hence, point defect equations were deduced and it was found that that oxygen vacancies were the prevailing ionic defects rather than electronic Nb compensation. From the aforementioned results, ultrathin wall nanotubes formed on TiNb alloy were achieved, for the first time, with clear representation of the oxide layer composition. Such oxide layer showed better stability upon annealing at high temperatures. Although, UV-Vis test results showed small or negligible enhancement in the absorption, profile the photo-electrochemical measurements showed much higher photocurrent for Ti-Nb oxide alloy than bare TiO2 prepared at the same conditions for the sake of comparison. In conclusion, the Ti-Nb NTs showed enhanced stability over a wide range of temperatures, where the transition from anatase to rutile was shifted to higher temperature in addition to an increase in the photoconversion capability, resulting in a more efficient water splitting process

Autism: A Neurodevelopmental Disorder and a Stratum for Comorbidities

Autism is a neurodevelopmental disorder which is more common in males than females. It is characterized by social communication disorders and restricted repetitive behaviors. There is wide heterogeneity in its etiology, clinical presentations, management and consequently prognosis. Although the etiology of autism remains unclear, the most currently proven theory is that it is a complex neurodevelopmental disorder that displays “brain network abnormalities”. fMRI studies have shown decreased brain connectivity or functional synchronization between frontal and more posterior cortical regions. Dynamic brain activity through high resolution electroencephalograghy (EEG) has revealed local overconnectivity and long-range underconnectivity. This disrupted connectivity pattern would involve connectivity between hemispheres (corpus callosum), together with axonal and synaptic connectivity within each hemisphere. Inconsistent morphometric changes involving both gray and white matter structure also exist. Clinically, autism is associated with multiple comorbidities (somatic, neurologic and psychiatric); some of which are attention deficit hyperactivity disorder, dyspraxia, and sensory processing disorders

Evaluation of Some Genotypes of Wheat (Triticum Durum L.) Under Conditions in Al Jabal Al Akhdar - Libya.

The experiment was conducted at the research farm of the College of Agriculture during the season (2019-2020) to evaluate the performance of six genetic compositions under semi-arid conditions using the green fodder. These compositions were obtained from the International Center for Agricultural Research in Dry Areas (ICARDA) and the International Maize and Wheat Improvement Center (CIMMYT), compared to the local variety "Ain Al-Faras." The treatments were planted according to a randomized complete block design (RCBD) with three replications. Significant differences were observed among all the genetic compositions for all the studied traits. The variety "Ain Al-Faras" outperformed the other genetic compositions in plant height, spike length, number of grains per spike, grain yield, straw yield, and biological weight, with values of 86 cm, 9.65 cm, 61 grains/spike, 1.14 tons/ha, 10.68 tons/ha, and 11.82 tons/ha, respectively. Genetic composition 2020-741 also excelled in the trait of number of grains per spike (52.33), while genetic composition D2020-72 exhibited superiority in the trait of thousand-grain weight (63.35 g). Moreover, genetic composition D2020-4 showed a higher harvest index compared to the other genetic compositions, with a value of 12.91. The results indicated that the values of phenotypic variance were close to the values of genetic variance for most of the studied traits. The highest heritability ratio was observed for the traits of number of grains per spike and grain yield. High relative genetic advance values were recorded along with high values of specific combining ability for both the number of grains per spike and grain yield. Therefore, it is possible to infer the genetic composition through morphological data, and such traits can be considered as selection criteria for improving these crops

Corporate social responsibility in Small and Medium-Sized Enterprises (SMEs): A Saudi Arabian perspective

While the interest in Corporate Social Responsibility (CSR) is rising globally, it is frequently portrayed as a ‘luxury good’ that only large companies can afford. However, an emerging stream of literature is recognising the positive affinities between Small and Medium Enterprises (SMEs) and CSR, and the potential advantages that SMEs can gain by engaging in CSR practices. This new approach is mainly limited to studying SMEs operating in developed countries. Moreover, while there is a growing trend in CSR research in developing countries, there is still limited attention to CSR in the economically significant region of the Middle East, particularly in the Kingdom of Saudi Arabia (KSA). This thesis, therefore, aims to critically evaluate how CSR is conceived and practised in Saudi SMEs and how they can engage with CSR as an important contemporary business challenge. By employing stakeholder theory and other CSR theories explaining the SME-society relationship, the study pays particular attention to contextual factors, i.e. cultural, economic, and legal, that shape the understanding of CSR and may promote or hinder CSR engagement. A qualitative research approach was adopted to achieve the objectives of this study. Data was gathered through thirty-two semi-structured interviews with SME owner-managers and representatives of government agencies concerned with the development of the SME sector. The findings reveal that SME owner-managers’ business values are commonly influenced by a mix of social and profit priorities that shape the CSR understanding and decisions of Saudi SMEs. SME owner-managers show a moderate CSR awareness, largely associated with philanthropic modes of giving, highlighting the prevailing role of local Islamic tradition. CSR is informally managed, with no dedicated department, budget, or public reporting. Yet, non-philanthropic CSR activities are strategically practised, across different functions, in terms of mitigating and transforming value chain social impacts with a focus on internal CSR activities. This stems from CSR being mostly internally motivated by the longstanding precepts of Islamic teaching and the practical benefits/challenges such as staff motivation and cash limitations. Hence, CSR benefits are generally intangible with an emphasis on the spiritual benefits resulting from viewing God as a highly salient stakeholder. These results suggest that the CSR phenomenon is essentially context-sensitive, where religion along with other contextual factors identified in this study (e.g. government regulations, education system, social media, and MNCs), have a potential role in stimulating CSR among Saudi SMEs. Addressing these factors may resolve identified challenges relating to CSR awareness, institutional support and pressure, and CSR incentives. This thesis contributes to filling a knowledge gap by providing new insights into CSR behaviour and approaches in an under-researched area, i.e. CSR in SMEs in KSA. It also contributes by extending the application of stakeholder theory to KSA by including a spiritual entity (God) as a primary stakeholder. Further, this work proposes several theoretical/conceptual frameworks, e.g. the Saudi SMEs’ CSR pyramid, and CSR benefits for Saudi SMEs, that may be considered transferable to other nations with a similar context, i.e. Muslim majority countries. Finally, business practitioners and policymakers can use the findings of this thesis to support the CSR strategies of SMEs and increase their CSR engagement