514 research outputs found

    Robust Star Detection for Cubic-Centimeter Star Imager

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    Multispectral Deep Neural Network Fusion Method for Low-Light Object Detection

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    Despite significant strides in achieving vehicle autonomy, robust perception under low-light conditions still remains a persistent challenge. In this study, we investigate the potential of multispectral imaging, thereby leveraging deep learning models to enhance object detection performance in the context of nighttime driving. Features encoded from the red, green, and blue (RGB) visual spectrum and thermal infrared images are combined to implement a multispectral object detection model. This has proven to be more effective compared to using visual channels only, as thermal images provide complementary information when discriminating objects in low-illumination conditions. Additionally, there is a lack of studies on effectively fusing these two modalities for optimal object detection performance. In this work, we present a framework based on the Faster R-CNN architecture with a feature pyramid network. Moreover, we design various fusion approaches using concatenation and addition operators at varying stages of the network to analyze their impact on object detection performance. Our experimental results on the KAIST and FLIR datasets show that our framework outperforms the baseline experiments of the unimodal input source and the existing multispectral object detectors

    Effects of some chemical detergents additions on concrete

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    Usually, the drainage network made of concrete and which fall under the infrastructure in cities. This research aims to study the corrosion of cement concrete under the influence of Washing Detergents, as well as determine the negative influence on some properties such as weight and mechanical resistance. The results showed that sodium phosphate salts by 27-35% of the weight of the detergent has led to weaken the resistance of the pressure of the cement mortar by 5%, and sodium sulphate salts and sodium chloride led to weaken on pressure resistance and inflexion by 15%. Corrosion Index showe proposed sharp decline very resistant to detour - the pressure resistance by up to 30%. Keywords: Concrete. Detergent. Corrosion. Resistance. Mechanical resistance, Weight. Index

    Estimating Willingness-To-Pay for Reduction in Uncertainty in Water Quality of Contaminated Aquifers

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    Management of contaminated aquifers is challenged by the limited resources available to monitor and remediate a large number of contaminated sites. Earlier research recognized the negative impacts of spatial data scarcity on the success of aquifer monitoring and remediation plans. Therefore, there exists an important question on how to allocate limited resources to collect additional information to better estimate the risks and remediation priorities versus the willingness to pay by the society. This work introduces one of the early applications of structural benefit transfer to quantify welfare impacts of improving aquifer monitoring in terms of willingness-to-pay (WTP). This work uses health risk assessment methodology and introduces a practical socio-economic framework to estimate individuals’ WTP for a proposed improvement in data gathering. The proposed methodology develops scenarios of uncertainty reductions in subsurface heterogeneity by collecting additional spatial data to reduce health risk to target population and computed the health-economic impact to estimate the aggregate WTP. The variability of characteristics of the target population is represented through probabilistic distributions of income, health state, age, and risk exposure parameters. The proposed methodology produced predictions of WTP that are consistent with the patterns expected in the economic theory and literature. Keywords: Groundwater, contamination, uncertainty reduction, additional data, Willingness-to-Pa

    Evaluation of Communication Induced Checkpointing Approaches for Reconfiguration-Based Fault-Tolerance in Embedded Systems

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    Reconfiguration-Based Fault-Tolerance is an approach to developing dependable safety-critical embedded applications, where redundant active or standby resources are used to cope with faults through a system reconfiguration at run-time. Compared to traditional hardware and software redundancy, it is a promising technique that may achieve dependability with a significant reduction in cost, size, weight, and power requirements. Reconfiguration necessitates using proper checkpointing protocols to support state reservation to ensure correct task restarts after a system reconfiguration. Communication Induced Checkpointing (CIC) protocols are well developed and understood for large parallel and information systems, but not much has been done for resource limited embedded systems. This paper implements four common CIC protocols in a resource constrained distributed embedded system with a Controller Area Network (CAN) backbone. An example feedback control system implementation is used for a case study. The four implemented protocols are described and performances are contrasted. The paper compares the protocols in terms of network bandwidth consumptions, CPU usages, checkpointing times, and checkpoint sizes in additional to the traditional measures of forced to local checkpoint rations and total number of checkpoints

    The environmental impacts of calcium chloride addition to cement on reinforcing steel corrosion

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    An alternative use of a specific type of cement for a particular purpose, usually we can change some properties of available cement by using the appropriate additions, with some negative side effects in some cases. In this research have been suggested values ??of calcium chloride(CaCl2) additions for use in concrete admixtures as an agent factor in accelerating the process of cement setting, to clarify the extent of the negative impacts that could be induced, such as alkalinity decline of solution and the impact of the chemical composition of used cement on reinforcing steel. Chloride ion present in low alumina cement mortar was detected quickly, while it needed to increase calcium chloride content to double in moderate alumina cement mortar. The results showed that the depth of carbonation when samples of different composition and with various w/c ratio treated by stream was faster in low ammonia cement mortar from moderate ammonia and faster in mortar poor than in mortar rich, In addition, depth of carbonation increased when the calcium chloride content in cement was very small. Electrical potential of steel in cement mortar inversely proportional with increasing calcium chloride content and with increasing in water/cement ratio and increasing sand content in cement mortar medium ammonia. The lowest level of steel oxidation observed in mortar consisting of cement medium ammonia and the rate of corrosion increases when samples treated by stream in all cases. Keywords: Calcium Chloride, Oxidation, Reinforcement, Stream Treatment, Carbonation, Concrete admixtures, Electric potentia

    Wearable IMU for Shoulder Injury Prevention in Overhead Sports

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    Body-worn inertial sensors have enabled motion capture outside of the laboratory setting. In this work, an inertial measurement unit was attached to the upper arm to track and discriminate between shoulder motion gestures in order to help prevent shoulder over-use injuries in athletics through real-time preventative feedback. We present a detection and classification approach that can be used to count the number of times certain motion gestures occur. The application presented involves tracking baseball throws and volleyball serves, which are common overhead movements that can lead to shoulder and elbow overuse injuries. Eleven subjects are recruited to collect training, testing, and randomized validation data, which include throws, serves, and seven other exercises that serve as a large null class of similar movements, which is analogous to a realistic usage scenario and requires a robust estimator

    Visualizing shear bands in 3-D using axisymmetric sample: An experimental study

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    In this study a qualitative description of the occurrence of shear bands produced by a sudden impact on an axisymmetric specimen made of medium carbon steel 0.45% C is given. A simple experiment was developed aimed at producing a pinch shear stress in the front side of the test sample in order to visualize shear bands in 3-D. Curve fitting using MATLAB was employed based on the points taken from the images of the front section of the test sample. The predictions of the curve fitting suggests a hyperbolic section leading to the conclusion that within the sample there is a double cone region of material where the shear band region is located on its outer surface. The formation of the shear band is explained by the fact that the interaction of the stress wave front with the free surface of the test sample produces reflection waves that attenuate the incoming stress wave inwards leading to a stress gradient in the plane of the front side of the specimen that causes shear localization. Also, the progressively increasing cross sectional area of the test sample causes the expansion of the wave front, which also results in a stress gradient in the normal direction of the front side of the specimen. So the formation of shear bands depends not only on the impact momentum and strain rates but also on the sample\u27s geometry. \ua9 2015 The Author
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