4,077 research outputs found

    Studies of the microenvironment and microflora of the canine external ear canal

    Get PDF
    The aims of this study were to investigate aspects of the aural microenvironment in dogs. The aural microflora, histological features of the aural integument, and biochemical components of cerumen from healthy canine ears and those with otitis externa were studied. Interactions between canine cerumen and one member of the resident aural flora, Malassezia pachydermatis were also investigated. Gram-positive, coagulase-negative cocci, and M.pachydermatis were the most common resident flora found in 52 healthy canine external ears. Microscopic examination of cytological smears from cerumen and microbiological culture indicated that these organisms were present in low numbers. Gram-positive coagulase positive staphylococci, Gram-negative rods, and M.pachydermatis were isolated most frequently from 27 canine ears affected by otitis externa. Eighty percent of these inflamed ears were associated with microbial overgrowth. The numbers of microorganisms found in cerumen cytological smears appear to be correlated to the growth density of microbial colonies on culture plates. In an anatomical survey of the external ear canal, 40 canine ears were examined. The average length of the cartilaginous part of these canals was 5.3 cm. The diameter at the most proximal end of the annular cartilage averaged 0.5 cm; at the proximal end of the auricular cartilage the mean diameter was 0.7 cm; at the distal extremity of the ear canal, the average diameter was 4.8 cm. Morphometric stereology was used to evaluate histological features of 28 clinically normal and 15 otitic canine ears at four anatomical levels. Marked variation was found in the distribution of sebaceous and apocrine glands in the aural integument in healthy ears and those with otitis

    Wireless personal area networks and free-space optical links

    Get PDF
    This thesis is concerned with the link layer design of indoor (IrDA) and outdoor infrared links, as well as the performance of the higher layers of two major Wireless Personal Area Network (WPAN) technologies: IrDA and Bluetooth. Recent advancesin wireless technology have made it possible to put networking technology into small portable devices. During the past few years, WPAN technologies have been the subject of a tremendous growth both in research and development. Although many studies have been conducted on wireless links to address different issues on physical and link layers, wireless communications are still characterised by high error rates becauseof the frequently changing medium. On the other hand, performance studies of the higher layers are also very important. In this thesis, for the first time, a comprehensivestudy of the interactions betweenthe higher and the lower protocol layers of IrDA and Bluetooth has been carried out to improve the overall system performance. Mathematical models for the link layers are introduced for the infrared systems: infrared data association (IrDA) and free space optics (FSO). A model for the IrDA (indoor infrared) link layer is developed by considering the presence of bit errors. Based on this model, the effect of propagation delay on the link through put is investigated. An optimization study is also carried out to maximize the link throughput. FSO (outdoor infrared) links are often characterized by high speed and long link distance. A mathematical model for the FSO link layer is also developed. Significant improvement of the link throughput is achieved by optimizing the link parameters. Based on the link layer model, the performance of the IrDA higher layers (transport, session and application layers) is investigated. First, a mathematical model of TinyTP (transport protocol) is elaborated and subsequently verified by simulations. The effects of multiple connections and available buffer size are investigated. The throughput at the TinyTP level is optimized for different buffer sizes. Subsequently, the session layer, including Object Exchange (OBEX) and IrDA Burst (IrBurst) protocols, is studied and modelled. The derived mathematical model is verified by simulation results. A set of protocol parameters and hardware selection guidelines is proposed to optimize the overall system performance while also keeping the hardware requirementto a minimum. Finally, two rapidly developing IrDA applications, IrDA financial messaging(IrFM) and IrDA simple connection (IrSC), are studied. IrFM is investigated by comparison to other digital payment technologies, while the performance of IrSC is compared in two different technical approaches. In order to improve the throughput and minimize the transmission delay for the Bluetooth data applications, a systematic analysis is carried out for the Bluetooth Logical Link Control and Adaptation Layer Protocol (L2CAP). L2CAP is layered above the Bluetooth link layer (Baseband) and is essential to Bluetooth data applications. A simple and intuitive mathematical model is developed to derive simple equations for the L2CAP throughput and the average packet delay. The derived throughput equation, which is validated by simulations, takes into account bit errors as well as packet retry limits. Finally, a number of easy-to-implement performance enhancement schemes are proposed, including the optimum use of the protocol parameters

    Collinear facilitation: Effect of additive and multiplicative external noise

    Get PDF
    AbstractThe detectability of a Gabor patch is improved by the presence of collinear flanking Gabors, this phenomenon is termed collinear facilitation. In experiment 1, we investigate the effects of adding 2D spatial luminance noise as a means of investigating different transects through the suprathreshold contrast space to see whether facilitation is ubiquitous throughout the contrast domain or whether it is confined to absolute contrast threshold. The results show that adding luminance noise abolishes the facilitation, showing it is confined to absolute threshold. In experiment 2, we assess whether 2nd order stimuli exhibit collinear facilitation and whether 1st order flanks can induce facilitation in 2nd order stimuli and vice versa. Our results suggest that collinear facilitation, albeit weaker, does occur for some 2nd order stimuli but we did not find any 1st/2nd order interactions, suggesting separate 1st/2nd order cortical processing streams, at least at the level at which this phenomenon occurs. Our two main findings, namely the lack of facilitation at suprathreshold contrasts and its presence for 2nd order processing argue against it playing a pivotal role in contour integration which does occur at all contrasts but not for these 2nd order stimuli

    Wireless personal area networks and free-space optical links

    Get PDF
    This thesis is concerned with the link layer design of indoor (IrDA) and outdoor infrared links, as well as the performance of the higher layers of two major Wireless Personal Area Network (WPAN) technologies: IrDA and Bluetooth. Recent advancesin wireless technology have made it possible to put networking technology into small portable devices. During the past few years, WPAN technologies have been the subject of a tremendous growth both in research and development. Although many studies have been conducted on wireless links to address different issues on physical and link layers, wireless communications are still characterised by high error rates becauseof the frequently changing medium. On the other hand, performance studies of the higher layers are also very important. In this thesis, for the first time, a comprehensivestudy of the interactions betweenthe higher and the lower protocol layers of IrDA and Bluetooth has been carried out to improve the overall system performance. Mathematical models for the link layers are introduced for the infrared systems: infrared data association (IrDA) and free space optics (FSO). A model for the IrDA (indoor infrared) link layer is developed by considering the presence of bit errors. Based on this model, the effect of propagation delay on the link through put is investigated. An optimization study is also carried out to maximize the link throughput. FSO (outdoor infrared) links are often characterized by high speed and long link distance. A mathematical model for the FSO link layer is also developed. Significant improvement of the link throughput is achieved by optimizing the link parameters. Based on the link layer model, the performance of the IrDA higher layers (transport, session and application layers) is investigated. First, a mathematical model of TinyTP (transport protocol) is elaborated and subsequently verified by simulations. The effects of multiple connections and available buffer size are investigated. The throughput at the TinyTP level is optimized for different buffer sizes. Subsequently, the session layer, including Object Exchange (OBEX) and IrDA Burst (IrBurst) protocols, is studied and modelled. The derived mathematical model is verified by simulation results. A set of protocol parameters and hardware selection guidelines is proposed to optimize the overall system performance while also keeping the hardware requirementto a minimum. Finally, two rapidly developing IrDA applications, IrDA financial messaging(IrFM) and IrDA simple connection (IrSC), are studied. IrFM is investigated by comparison to other digital payment technologies, while the performance of IrSC is compared in two different technical approaches. In order to improve the throughput and minimize the transmission delay for the Bluetooth data applications, a systematic analysis is carried out for the Bluetooth Logical Link Control and Adaptation Layer Protocol (L2CAP). L2CAP is layered above the Bluetooth link layer (Baseband) and is essential to Bluetooth data applications. A simple and intuitive mathematical model is developed to derive simple equations for the L2CAP throughput and the average packet delay. The derived throughput equation, which is validated by simulations, takes into account bit errors as well as packet retry limits. Finally, a number of easy-to-implement performance enhancement schemes are proposed, including the optimum use of the protocol parameters.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Ontology-based Fuzzy Markup Language Agent for Student and Robot Co-Learning

    Full text link
    An intelligent robot agent based on domain ontology, machine learning mechanism, and Fuzzy Markup Language (FML) for students and robot co-learning is presented in this paper. The machine-human co-learning model is established to help various students learn the mathematical concepts based on their learning ability and performance. Meanwhile, the robot acts as a teacher's assistant to co-learn with children in the class. The FML-based knowledge base and rule base are embedded in the robot so that the teachers can get feedback from the robot on whether students make progress or not. Next, we inferred students' learning performance based on learning content's difficulty and students' ability, concentration level, as well as teamwork sprit in the class. Experimental results show that learning with the robot is helpful for disadvantaged and below-basic children. Moreover, the accuracy of the intelligent FML-based agent for student learning is increased after machine learning mechanism.Comment: This paper is submitted to IEEE WCCI 2018 Conference for revie

    THE BIOMECHANICALANALYSIS OF TAEKWONDO AXE-KICK IN SENIOR HIGH SCHOOL ATHLETIC

    Get PDF
    The purpose of this study was to investigate the biomechanical factors of the Taekwondo axe-kick and compare the differences between male and female athletes for timing kinematicsand kinetics. The data gained from 23 test subjects of the Taekwondo team from the junior high school (male:16, female:?). Base on the results and discussion of the study, we have reached the following conclusion: the average movement speed has significant difference between male and female groups. The average movement speed has significant positive correlation with the peak vertical ground reaction force (body weight), the peak front-rear ground reaction and impulse at the kicking leg. While the kicking leg attacked the target, the higher point of the kicking leg and the larger power at the peak tront-rear ground reaction force, the faster attacking velocity(the resultant of toe velocity) at the target
    • …
    corecore