14 research outputs found
Robust Transport and Assembly Automation System Using Vision-Based Control Using UAV
No full textWe propose an automated system that moves blocks to a specific location, such as a block map, using Unmanned Aerial Vehicle (UAV). The system was developed in a simulation environment using Gazebo simulator, and the test environment was set with different GPS noise and illuminance in order to resemble the real environment. To increase the accuracy of the system, we used an algorithm that picks up and places blocks using vision-based controls using deep learning-based object detection and recognition, not just GPS based control. In addition, when picking up and placing blocks, it is easy to execute by using a magnet module rather than a typical manipulator. Our proposed system in simulation experiments in various environments consistently showed excellent performance. The system seems to have robust performance in a more difficult environment than existing robots and has simplicity and efficiency in execution. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd
Drone Swarm Operating and Monitoring System for States Error Compensation
No full textThere have been many studies trying to solve existing research topics using multiple drones instead of one. This is because multiple drones are better than a single drone to perform missions more efficiently and perform complex missions. To operate a swarm drone, it consumes a lot of resources only by its size and scale. Since the scale cannot be reduced, the overall burden decreases when a small drone is operated. However, a small-sized drone has a lot of problems with rtk-gps, magnetometer noise, RF/ESC noise, and motor vibration. For these reasons, there are cases where state estimation is not properly performed. In this paper, therefore, we propose a system that can perform swarm flight using such a small drone, monitor the state error of each drone, and correct it. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd
PtomtAPX is an autonomous lignification peroxidase during the earliest stage of secondary wall formation in Populus tomentosa Carr
No full text© 2022, The Author(s), under exclusive licence to Springer Nature Limited.At present, a cooperative process hypothesis is used to explain the supply of enzyme (class III peroxidases and/or laccases) and substrates during lignin polymerization. However, it remains elusive how xylem cells meet the needs of early lignin rapid polymerization during secondary cell wall formation. Here we provide evidence that a mitochondrial ascorbate peroxidase (PtomtAPX) is responsible for autonomous lignification during the earliest stage of secondary cell wall formation in Populus tomentosa. PtomtAPX was relocated to cell walls undergoing programmed cell death and catalysed lignin polymerization in vitro. Aberrant phenotypes were caused by altered PtomtAPX expression levels in P. tomentosa. These results reveal that PtomtAPX is crucial for catalysing lignin polymerization during the early stages of secondary cell wall formation and xylem development, and describe how xylem cells provide autonomous enzymes needed for lignin polymerization during rapid formation of the secondary cell wall by coupling with the programmed cell death process.11Nsciescopu
Ultrafast charge transfer coupled with lattice phonons in two-dimensional covalent organic frameworks
No full text© 2019, The Author(s). Covalent organic frameworks (COFs) have emerged as a promising light-harvesting module for artificial photosynthesis and photovoltaics. For efficient generation of free charge carriers, the donor–acceptor (D-A) conjugation has been adopted for two-dimensional (2D) COFs recently. In the 2D D-A COFs, photoexcitation would generate a polaron pair, which is a precursor to free charge carriers and has lower binding energy than an exciton. Although the character of the primary excitation species is a key factor in determining optoelectronic properties of a material, excited-state dynamics leading to the creation of a polaron pair have not been investigated yet. Here, we investigate the dynamics of photogenerated charge carriers in 2D D-A COFs by combining femtosecond optical spectroscopy and non-adiabatic molecular dynamics simulation. From this investigation, we elucidate that the polaron pair is formed through ultrafast intra-layer hole transfer coupled with coherent vibrations of the 2D lattice, suggesting a mechanism of phonon-assisted charge transfe
Button Filtering for Converting Image to Coordinates of Swarming Drones
No full textIn this paper, we propose Button Filtering which is a method of non-linear filtering that creates a set of points from an image. This set of points can be used as coordinates of drones. Button filtering is considered nonlinear filtering because it is not applied as convolution, which is used on typical filtering. Nevertheless, it is easy and fast owing to use of a simple button mask, and it has the advantage of immense extendibility. To date, it is only available for the 8-bit gray scale image, which is generally the edge of the original image or masked image. However, it can be applied to a color image, two-dimensional images in a 3D space, and even three-dimensional objects. In this paper, we present the use of button filtering for any object in any image. To this end, we must perform pre-processing before button filtering. We thus present six methods that can handle almost every image type and identify the specific methods that are effective for certain image types
Software dependability in the operational phase
No full textSoftware quality should be built-in and maintained throughout the software life cycle, which requires understanding of software dependability in actual environments. This thesis discusses how to develop analysis techniques for evaluating the dependability of operational software using real measurements while taking design issues into account. The issues addressed include fault categorization and characterization of error propagation, symptom-based diagnosis of recurrent software failures, identification of software fault tolerance, evaluation of the impact of software faults on the overall system, and the development of techniques for analyzing multiway failure dependencies among software and hardware modules. The process is illustrated using a case study of the Tandem GUARDIAN operating system.Using process pairs in Tandem systems, which was originally intended for tolerating hardware faults, allows the system to tolerate about 70% of reported faults in the system software that cause processor failures. The loose coupling between processors, which results in the backup execution (the processor state and the sequence of events) being different from the original execution, is a major reason for the measured software fault tolerance. About 72% of reported field software failures in Tandem systems are recurrences of previously reported faults. In addition to the conventional approach of reducing the number of faults in software, software dependability in Tandem systems can be enhanced by reducing the recurrence rate and by improving the robustness of process pairs and the system configuration. An approach for automatically diagnosing recurrences based on their symptoms is developed. The results of evaluations of the effectiveness of the approach show that between 75% and 95% of recurrences can be successfully identified by matching failure symptoms, such as stack traces and problem detection locations. Less than 10% of faults are misdiagnosed.Made available in DSpace on 2011-05-07T14:29:40Z (GMT). No. of bitstreams: 2
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