DS-K3DOM: 3-D Dynamic Occupancy Mapping with Kernel Inference and Dempster-Shafer Evidential Theory

Occupancy mapping has been widely utilized to represent the surroundings for autonomous robots to perform tasks such as navigation and manipulation. While occupancy mapping in 2-D environments has been well-studied, there have been few approaches suitable for 3-D dynamic occupancy mapping which is essential for aerial robots. This paper presents a novel 3-D dynamic occupancy mapping algorithm called DSK3DOM. We first establish a Bayesian method to sequentially update occupancy maps for a stream of measurements based on the random finite set theory. Then, we approximate it with particles in the Dempster-Shafer domain to enable real time computation. Moreover, the algorithm applies kernel based inference with Dirichlet basic belief assignment to enable dense mapping from sparse measurements. The efficacy of the proposed algorithm is demonstrated through simulations and real experiments.Comment: 7 pages, 2 figures, submitted to ICRA 202

Proximity Effect in Nb/Au/CoFe Trilayers

We have investigated the superconducting critical temperatures of Nb/Au/CoFe trilayers as a function of Au and CoFe thicknesses. Without the CoFe layer the superconducting critical temperatures of Nb/Au bilayers as a function of Au thickness follow the well-known proximity effect between a superconductor and a normal metal. The superconducting critical temperatures of Nb/Au/CoFe trilayers as a function of Au thickness exhibit a rapid initial increase in the small Au thickness region and increase slowly to a limiting value above this region, accompanied by a small oscillation of Tc. On the other hand, the superconducting critical temperatures of Nb/Au/CoFe trilayers as a function of CoFe thickness show non-monotonic behavior with a shallow dip feature. We analyzed the Tc behavior in terms of Usadel formalism and found that most features are consistent with the theory, although the small oscillation of Tc as a function of the Au thickness cannot be accounted for. We have also found quantitative values for the two interfaces: Nb/Au and Au/CoFe.Comment: 25 pages, 6 figure

The impact of the prenatal ultrasonography on birth of babies with Korean pediatric surgical index diseases

PURPOSE: The purpose of this study is to examine the impact of prenatal ultrasonography (US) on the birth of babies with diseases listed on the Korean pediatric surgery index diseases (IDs). METHODS: Depending the ease of diagnosis using prenatal US, [diagnostic facility if prenatal US] IDs were divided into easily diagnosed (ED), not easily diagnosed (NED) and detected with difficulty (DD) groups. Five-year data were obtained for the total live birth number (TBN) from the Korean Statistical Information Service, and the actual birth number of IDs (ABNID) from the Korean Health Insurance Review and Assessment Service. The certified incidences of IDs (I) were obtained from a prestigious textbook of pediatric surgery. The estimated abortion rate (AR) of fetus in each group was obtained using the following formula: AR (%) = [1 - (ABNID)/(TBN x I)] x 100. RESULTS: The AR with all IDs was 38 to 77%. The AR was 78 to 93% for ED group, 38 to 66% for NED group and 0% for DD group. CONCLUSION: In spite of high survival rates after treatment, the AR of each group depends on the ease of diagnosis using prenatal US in Korea. A recommendatory policy for the fetus with IDs should be urgently established after general consensus within the related medical societiesope

Enhanced overall efficiency of GaInN-based light-emitting diodes with reduced efficiency droop by Al-composition-graded AlGaN/GaN superlattice electron blocking layer

AlxGa1-xN/GaN superlattice electron blocking layers (EBLs) with gradually decreasing Al composition toward the p-type GaN layer are introduced to GaInN-based high-power light-emitting diodes (LEDs). GaInN/GaN multiple quantum well LEDs with 5- and 9-period Al-composition-graded AlxGa1-xN/GaN EBL show comparable operating voltage, higher efficiency as well as less efficiency droop than LEDs having conventional bulk AlGaN EBL, which is attributed to the superlattice doping effect, enhanced hole injection into the active region, and reduced potential drop in the EBL by grading Al compositions. Simulation results reveal a reduction in electron leakage for the superlattice EBL, in agreement with experimental results. (C) 2013 AIP Publishing LLC.open1133sciescopu

Echo Path Transfer Function Estimation for Spectral Subtraction-based Acoustic Echo Suppression

In this study, we propose a novel technique for spectral subtraction (SS)-based acoustic echo suppression (AES). Conventional AES methods based on SS apply fixed weights to the estimated echo path transfer function (EPTF) at the current signal segment and to the EPTF estimated until the previous time interval. We propose a new EPTF estimation approach that adaptively updates the weight parameters in response to abrupt changes in the acoustic environment. From the experiments, we conclude that the developed techniques can be successfully used for the SS-based AES systems