Implicit Neural Image Stitching With Enhanced and Blended Feature Reconstruction

Existing frameworks for image stitching often provide visually reasonable stitchings. However, they suffer from blurry artifacts and disparities in illumination, depth level, etc. Although the recent learning-based stitchings relax such disparities, the required methods impose sacrifice of image qualities failing to capture high-frequency details for stitched images. To address the problem, we propose a novel approach, implicit Neural Image Stitching (NIS) that extends arbitrary-scale super-resolution. Our method estimates Fourier coefficients of images for quality-enhancing warps. Then, the suggested model blends color mismatches and misalignment in the latent space and decodes the features into RGB values of stitched images. Our experiments show that our approach achieves improvement in resolving the low-definition imaging of the previous deep image stitching with favorable accelerated image-enhancing methods. Our source code is available at https://github.com/minshu-kim/NIS

Axion Haloscope Using an 18 T High Temperature Superconducting Magnet

We report details on the axion dark matter search experiment that uses the innovative technologies of a High-Temperature Superconducting (HTS) magnet and a Josephson Parametric Converter (JPC). An 18 T HTS solenoid magnet is developed for this experiment. The JPC is used as the first stage amplifier to achieve a near quantum-limited low-noise condition. The first dark matter axion search was performed with the 18 T axion haloscope. The scan frequency range is from 4.7789 GHz to 4.8094 GHz (30.5 MHz range). No significant signal consistent with Galactic dark matter axion is observed. Our results set the best limit of the axion-photon-photon coupling ($g_{a\gamma\gamma}$) in the axion mass range of 19.764 to 19.890 $\mu$eV. Using the Bayesian method, the upper bounds of $g_{a\gamma\gamma}$ are set at 0.98$\times|g_{a\gamma\gamma}^{\text{KSVZ}}|$ (1.11$\times|g_{a\gamma\gamma}^{\text{KSVZ}}|$) in the mass ranges of 19.764 to 19.771 $\mu$eV (19.863 to 19.890 $\mu$eV), and at 1.76 $\times|g_{a\gamma\gamma}^{\text{KSVZ}}|$ in the mass ranges of 19.772 to 19.863 $\mu$eV with 90\% confidence level, respectively. We report design, construction, operation, and data analysis of the 18 T axion haloscope experiment.Comment: PRD published versio

A User Interface System with See-Through Display for WalkON Suit: A Powered Exoskeleton for Complete Paraplegics

In the development of powered exoskeletons for paraplegics due to complete spinal cord injury, a convenient and reliable user-interface (UI) is one of the mandatory requirements. In most of such robots, a user (i.e., the complete paraplegic wearing a powered exoskeleton) may not be able to avoid using crutches for safety reasons. As both the sensory and motor functions of the paralyzed legs are impaired, the users should frequently check the feet positions to ensure the proper ground contact. Therefore, the UI of powered exoskeletons should be designed such that it is easy to be controlled while using crutches and to monitor the operation state without any obstruction of sight. In this paper, a UI system of the WalkON Suit, a powered exoskeleton for complete paraplegics, is introduced. The proposed UI system consists of see-through display (STD) glasses and a display and tact switches installed on a crutch for the user to control motion modes and the walking speed. Moreover, the user can monitor the operation state using the STD glasses, which enables the head to be positioned up. The proposed UI system is verified by experimental results in this paper. The proposed UI system was applied to the WalkON Suit for the torch relay of the 2018 Pyeongchang Paralympics

Analysis and Design of Power-Efficient H-Band CMOS Frequency Doubler Employing Gain Boosting and Harmonic Enhancing Techniques

This article presents a power-efficient frequency doubler employing gain boosting and harmonic-enhancing techniques. With a single transistor only, the gain boosting technique can reach the maximum achievable gain ( $G_{\mathrm {max}}$ ) by adding embedded passive components, thereby obtaining high voltage swings. Then, the transistor’s nonlinearity is essential, which is maximized by the harmonic transition scheme of the transistor operation along with high voltage swings. In addition, a harmonic reflector and a harmonic leakage canceller are employed for the second harmonic enhancement. The harmonic reflector prevents unwanted harmonic mixing by minimizing the incoming second harmonic current fed back to the input. The harmonic leakage canceller suppresses the leakage loss of the second harmonic current present at the output. Furthermore, thanks to a proposed dual-band output matching network, the output impedance is conjugately matched to achieve the $G_{\mathrm {max}}$ at the fundamental frequency while it is matched to extract the second harmonic output power simultaneously. To verify the proposed techniques, the prototype was designed as a single-stage circuit that does not require additional amplifying stages, which led to higher power efficiency and lower chip area. Implemented in a 65-nm CMOS process, the measurement results show a saturated output power of 0.9 dBm and 3-dB bandwidth of 26 GHz (237–263 GHz), respectively, while requiring a chip area of 0.071 mm2. Total power efficiency, including the effect of injected signal power, is 2.87 % while consuming only 37 mW dc power

EdgeIso: Effective Performance Isolation for Edge Devices

© 2020 IEEE.Edges enable cloud services to be provided at low-latency and efficiently reduce the amount of transferred data by placing latency-critical tasks close to users. However, multi-tasking results in resource contention on edge devices, making it challenging to meet the service level objectives (SLOs) of tasks. Compared to the clouds, edges have relatively limited resources, but their tasks are required to meet a higher level of SLOs than clouds. Furthermore, modern edge devices equipped with additional accelerators (e.g., GPU) may worsen the resource contention due to the edge's integrated architecture, sharing the memory bandwidth between CPUs and accelerators. To address these challenges, we present EdgeIso, a light-weight scheduler that dynamically isolates the performance of tasks on edges. EdgeIso periodically monitors the resource contention and mitigates the contention to meet the SLOs of tasks by efficiently enforcing several isolation techniques (e.g., DVFS and core allocation) in an incremental manner. Moreover, it detects the changes of task executions or offered loads for tasks, thus handling high load fluctuations adaptively. We implement EdgeIso as a user-level scheduler on the Linux integrates into an NVIDIA Jetson TX2. Our experimental results show that EdgeIso improves the performance of the low-latency tasks significantly while improving resource efficiency compared with both the offloading and reservation scheme used in clouds.N

Performance Evaluation of Photovoltaic Solar System with Different Cooling Methods and a Bi-Reflector PV System (BRPVS): An Experimental Study and Comparative Analysis

Reducing the price of solar photovoltaic (PV) systems has been a constant challenge. Despite recent advances, solar PV systems are still more costly than conventional energy resources. For the first time, this study examines the effectiveness of three different structures/materials: (i) silvered glass plane mirror; (ii) convex spherical mirrors; and (iii) aluminum (Al) foil as reflector. Comparative analysis of four different cooling techniques, i.e., water sprinkling system, passive heat sink method, active air fan method, and closed loop method, for enhancement of output power was performed. A novel Bi reflector solar PV system (BRPVS) was suggested to control the working of the reflectors. The Al foil enhanced the power output compared to the others. In addition, the effect of using a reflector on the temperature of a solar PV system was studied. High operating temperatures resulted in a decrease in the maximum output power under the same solar radiation conditions. The combined enhancement of the output power by both Al foil BRPVS system and cooling system was almost 22.75–38.55%. An optimal control algorithm to use cooling and BRPVS in an efficient manner is described

Searching for Invisible Axion Dark Matter with an 18 T Magnet Haloscope

We report the first search results for axion dark matter using an 18 T high-temperature superconducting magnet haloscope. The scan frequency ranges from 4.7789 to 4.8094 GHz. No significant signal consistent with the Galactic halo dark matter axion is observed. The results set the best upper bound of axion-photonphoton coupling (gaγγ ) in the mass ranges of 19.764 to 19.771 μeV (19.863 to 19.890 μeV) at 1.5 × jgKSVZ aγγ j (1.7 × jgKSVZ aγγ j), and 19.772 to 19.863 μeV at 2.7 × jgKSVZ aγγ j with 90% confidence level, respectively. This remarkable sensitivity in the high mass region of dark matter axion is achieved by using the strongest magnetic field among the existing haloscope experiments and realizing a low-noise amplification of microwave signals using a Josephson parametric converter.11Nsciescopu