Improved Activation Functions of Deep Convolutional Neural Networks for Image Classification

Department of Electrical EngineeringIn this thesis, we investigate the performance of various activation functions of deep convolutional neural networks (DCNNs) and propose new activation functions. First, we propose twofold parametric ReLU. We observed that time complexity of S-shaped ReLU is relatively huge due to the computation of forward and backward-pass propagation. Thus we removed translation parameters of S-shaped ReLU and design twofold parametric ReLU. Second, inspired by just noticeable difference of the Weber's law, we reflect the property that subjective sensation is proportional to the logarithm of image intensity. We formulate an activation function by modifying the logarithm function which is used only on the first layer of DCNNs. Experimental results show that the performances of the proposed activation functions are better than that of the existing activation functions.ope

Discovery of a rapid, luminous nova in NGC 300 by the KMTNet Supernova Program

We present the discovery of a rapidly evolving transient by the Korean Microlensing Telescope Network Supernova Program (KSP). KSP is a novel high-cadence supernova survey that offers deep ($\sim21.5$ mag in $BVI$ bands) nearly continuous wide-field monitoring for the discovery of early and/or fast optical transients. KSP-OT-201509a, reported here, was discovered on 2015 September 27 during the KSP commissioning run in the direction of the nearby galaxy NGC~300, and stayed above detection limit for $\sim$ 22 days. We use our $BVI$ light-curves to constrain the ascent rate, $-3.7(7)$ mag day$^{-1}$ in $V$, decay time scale, $t^{V}_{2}=1.7(6)$ days, and peak absolute magnitude, $-9.65\leq M_{V}\leq -9.25$ mag. We also find evidence for a short-lived pre-maximum halt in all bands. The peak luminosity and lightcurve evolution make KSP-OT-201509a consistent with a bright, rapidly decaying nova outburst. We discuss constraints on the nature of the progenitor and its environment using archival HST/ACS images and conclude with a broad discussion on the nature of the system.Comment: 7 pages in aastex6 two-column format, 4 figures; accepted in Ap

Phase Frequency Detector and Charge Pump for Low Jitter PLL Applications

In this paper a new technique is presented to improve the jitter performance of conventional phase frequency detectors by completely removing the unnecessary one-shot pulse. This technique uses a variable pulse-height circuit to control the unnecessary one-shot pulse height. In addition, a novel charge-pump circuit with perfect current-matching characteristics is used to improve the output jitter performance of conventional charge pumps. This circuit is composed of a pair of symmetrical pump circuits to obtain a good current matching. As a result, the proposed charge-pump circuit has perfect current-matching characteristics, wide output range, no glitch output current, and no jump output voltage. In order to verify such operation, circuit simulation is performed using 0.18 μm CMOS process parameters

Near-Infrared [Fe II] and H2 Line Observations of the Supernova Remnant 3C 396: Probing the Pre-supernova Circumstellar Materials

We present the results of near-infrared [Fe II] and H2 line imaging and spectroscopic observations of the supernova remnant 3C 396 using the Palomar 5 m Hale telescope. We detect long, filamentary [Fe II] emission delineating the inner edge of the radio emission in the western boundary of the remnant in imaging observations, together with a bright [Fe II] emission clump close to the remnant center. There appears to be faint, diffuse [Fe II] emission between the central clump and the western filamentary emission. The spectroscopic observations determine the expansion velocity of the central clump to be ~56 km/s. This is far smaller than the expansion velocity of 3C 396 obtained from X-ray observations, implying the inhomogeneity of the ambient medium. The electron number density of the [Fe II] emission gas is < 2,000 cm-3. The H2 line emission, on the other hand, lies slightly outside the filamentary [Fe II] emission in the western boundary, and forms a rather straight filament. We suggest that the [Fe II] emission represents dense clumps in the wind material from the red supergiant phase of a Type IIL/b progenitor of 3C 396 which have been swept up by the supernova remnant shocks. The H2 emission may represent either the boundary of a wind bubble produced during the main-sequence phase of the progenitor or molecular clumps left over inside the bubble. We propose that the near-infrared [Fe II] and H2 emission observed in several supernova remnants of Type IIL/b SNe likely has the same origin.Comment: 24 page including 8 figures; Accepted by Ap

(1,2-Dicarba-closo-dodeca­boran­yl)trimethyl­methanaminium iodide

The title compound, [1-(CH3)3NCH2-1,2-C2B10H11]+·I− or C6H22B10N+·I−, was obtained by the reaction of (1,2-dicarba-closo-dodeca­boran­yl)dimethyl­methanamine with methyl iodide. The asymmetric unit contains two iodide anions and two (o-carboran­yl)tetra­methyl­ammonium cations. The bond lengths and angles in the carborane cage are within normal ranges, but the N—Cmethyl­ene—Ccage angle is very large [120.2 (2)°] because of repulsion between the carborane and tetra­methyl­ammonium units. In the crystal, ions are linked through C—H⋯I hydrogen bonds