25 research outputs found
Real-Time Object Tracking via Meta-Learning: Efficient Model Adaptation and One-Shot Channel Pruning
We propose a novel meta-learning framework for real-time object tracking with
efficient model adaptation and channel pruning. Given an object tracker, our
framework learns to fine-tune its model parameters in only a few iterations of
gradient-descent during tracking while pruning its network channels using the
target ground-truth at the first frame. Such a learning problem is formulated
as a meta-learning task, where a meta-tracker is trained by updating its
meta-parameters for initial weights, learning rates, and pruning masks through
carefully designed tracking simulations. The integrated meta-tracker greatly
improves tracking performance by accelerating the convergence of online
learning and reducing the cost of feature computation. Experimental evaluation
on the standard datasets demonstrates its outstanding accuracy and speed
compared to the state-of-the-art methods.Comment: 9 pages, 5 figures, AAAI 2020 accepte
Future Changes in Surface Runoff over Korea Projected by a Regional Climate Model under A1B Scenario
This study assesses future change of surface runoff due to climate change over Korea using a regional climate model (RCM), namely, the Global/Regional Integrated Model System (GRIMs), Regional Model Program (RMP). The RMP is forced by future climate scenario, namely, A1B of Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). The RMP satisfactorily reproduces the observed seasonal mean and variation of surface runoff for the current climate simulation. The distribution of monsoonal precipitation-related runoff is adequately captured by the RMP. In the future (2040–2070) simulation, it is shown that the increasing trend of temperature has significant impacts on the intra-annual runoff variation. The variability of runoff is increased in summer; moreover, the strengthened possibility of extreme occurrence is detected in the future climate. This study indicates that future climate projection, including surface runoff and its variability over Korea, can be adequately addressed on the RMP testbed. Furthermore, this study reflects that global warming affects local hydrological cycle by changing major water budget components. This study adduces that the importance of runoff should not be overlooked in regional climate studies, and more elaborate presentation of fresh-water cycle is needed to close hydrological circulation in RCMs
Real-Time Object Tracking via Meta-Learning: Efficient Model Adaptation and One-Shot Channel Pruning
1
Determination of Plasma Potential Using an Emissive Probe with Floating Potential Method
Despite over 90 years of study on the emissive probe, a plasma diagnostic tool used to measure plasma potential, its underlying physics has yet to be fully understood. In this study, we investigated the voltages along the hot filament wire and emitting thermal electrons and proved which voltage reflects the plasma potential. Using a circuit model incorporating the floating condition, we found that the lowest potential on the plasma-exposed filament provides a close approximation of the plasma potential. This theoretical result was verified with a comparison of emissive probe measurements and Langmuir probe measurements in inductively coupled plasma. This work provides a significant contribution to the accurate measurement of plasma potential using the emissive probe with the floating potential method
On the Quenching of Electron Temperature in Inductively Coupled Plasma
Electron temperature has attracted great attention in plasma processing, as it dominates the production of chemical species and energetic ions that impact the processing. Despite having been studied for several decades, the mechanism behind the quenching of electron temperature with increasing discharge power has not been fully understood. In this work, we investigated the quenching of electron temperature in an inductively coupled plasma source using Langmuir probe diagnostics, and suggested a quenching mechanism based on the skin effect of electromagnetic waves within local- and non-local kinetic regimes. This finding provides insight into the quenching mechanism and has implications for controlling electron temperature, thereby enabling efficient plasma material processing
Refined Appearance Potential Mass Spectrometry for High Precision Radical Density Quantification in Plasma
As the analysis of complicated reaction chemistry in bulk plasma has become more important, especially in plasma processing, quantifying radical density is now in focus. For this work, appearance potential mass spectrometry (APMS) is widely used; however, the original APMS can produce large errors depending on the fitting process, as the fitting range is not exactly defined. In this research, to reduce errors resulting from the fitting process of the original method, a new APMS approach that eliminates the fitting process is suggested. Comparing the neutral densities in He plasma between the conventional method and the new method, along with the real neutral density obtained using the ideal gas equation, confirmed that the proposed quantification approach can provide more accurate results. This research will contribute to improving the precision of plasma diagnosis and help elucidate the plasma etching process
Characterization of SiO<sub>2</sub> Plasma Etching with Perfluorocarbon (C<sub>4</sub>F<sub>8</sub> and C<sub>6</sub>F<sub>6</sub>) and Hydrofluorocarbon (CHF<sub>3</sub> and C<sub>4</sub>H<sub>2</sub>F<sub>6</sub>) Precursors for the Greenhouse Gas Emissions Reduction
This paper proposes the use of environmentally friendly alternatives, C6F6 and C4H2F6, as perfluorocarbon (PFC) and hydrofluorocarbon (HFC) precursors, respectively, for SiO2 plasma etching, instead of conventional precursors C4F8 and CHF3. The study employs scanning electron microscopy for etch profile analysis and quadrupole mass spectrometry for plasma diagnosis. Ion bombardment energy at the etching conditions is determined through self-bias voltage measurements, while densities of radical species are obtained using quadrupole mass spectroscopy. The obtained results compare the etch performance, including etch rate and selectivity, between C4F8 and C6F6, as well as between CHF3 and C4H2F6. Furthermore, greenhouse gas (GHG) emissions are evaluated using a million metric ton of carbon dioxide equivalent, indicating significantly lower emissions when replacing conventional precursors with the proposed alternatives. The results suggest that a significant GHG emissions reduction can be achieved from the investigated alternatives without a deterioration in SiO2 etching characteristics. This research contributes to the development of alternative precursors for reducing global warming impacts
On Encapsulated Dielectric Barrier Discharge Plasma Sources for Radar Cross Section Reduction in Mobile Environments
This paper deals with the practical application of Radar Cross Section (RCS) reduction technology using plasma. Although various plasma application technologies for RCS reduction have been studied, there are still many issues to be addressed for practical implementation. In order to achieve actual application, the discharge should be sustained regardless of the external environment of the aircraft. It is also important to investigate the actual plasma parameters to determine the expected RCS reduction effect. Building upon previous studies that optimized the electrodes for RCS reduction, this study fabricates a Dielectric Barrier Discharge (DBD) source suitable for dynamic environments and verifies the power consumption during one cycle of plasma generation. The obtained results are expected to contribute to the optimization of DBD electrodes for plasma RCS reduction