5G 3GPP-like Channel Models for Outdoor Urban Microcellular and Macrocellular Environments

For the development of new 5G systems to operate in bands up to 100 GHz, there is a need for accurate radio propagation models at these bands that currently are not addressed by existing channel models developed for bands below 6 GHz. This document presents a preliminary overview of 5G channel models for bands up to 100 GHz. These have been derived based on extensive measurement and ray tracing results across a multitude of frequencies from 6 GHz to 100 GHz, and this document describes an initial 3D channel model which includes: 1) typical deployment scenarios for urban microcells (UMi) and urban macrocells (UMa), and 2) a baseline model for incorporating path loss, shadow fading, line of sight probability, penetration and blockage models for the typical scenarios. Various processing methodologies such as clustering and antenna decoupling algorithms are also presented.Comment: To be published in 2016 IEEE 83rd Vehicular Technology Conference Spring (VTC 2016-Spring), Nanjing, China, May 201

Robust Probabilistic Time Series Forecasting

Probabilistic time series forecasting has played critical role in decision-making processes due to its capability to quantify uncertainties. Deep forecasting models, however, could be prone to input perturbations, and the notion of such perturbations, together with that of robustness, has not even been completely established in the regime of probabilistic forecasting. In this work, we propose a framework for robust probabilistic time series forecasting. First, we generalize the concept of adversarial input perturbations, based on which we formulate the concept of robustness in terms of bounded Wasserstein deviation. Then we extend the randomized smoothing technique to attain robust probabilistic forecasters with theoretical robustness certificates against certain classes of adversarial perturbations. Lastly, extensive experiments demonstrate that our methods are empirically effective in enhancing the forecast quality under additive adversarial attacks and forecast consistency under supplement of noisy observations. The code for our experiments is available at https://github.com/tetrzim/robust-probabilistic-forecasting.N

An n-heterocyclic-carbene-tetracyanoethylene zwitterion: Experimental and theoretical study on its formation and reactivity

The direct addition of tetracyanoethylene (TCNto the carbene center of 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPwas successfully demonstrated. The IPr-TCNE adduct, that is, zwitterion 1, clearly differs from the typical [2+1]-cycloaddition products obtained from the reaction of carbenes with olefins. The results obtained from experimental and theoretical studies suggest that adduct 1 disassembles into IPr and TCNE, which is followed by the addition of IPr to the nitrile carbon atom of TCNE and subsequent isomerization into a thermodynamically more stable singlet nitrene intermediate. This intermediate is then captured by an additional molecule of TCNE to afford another heterocycle. This study reveals a unique example of the reactivity between N-heterocyclic carbenes and olefins. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim11sciescopu

Triazenyl Radicals Stabilized by N-Heterocyclic Carbenes

Not with standing the notable progress in the synthesis of N-heterocyclic carbene-stabilized radicals, aminyl radicals, supported by NHCs or otherwise, have been scarcely studied due to synthetic challenges. Triazenyl radical is a particular form of aminyl radical that contains three adjacent nitrogen atoms, and offers intriguing possibilities for unique reactivity and physical properties stemming from expected delocalization of the spin density over the NNN moiety and its conjugated substituents. Here, we report the synthesis and full characterization of the first NHC-stabilized triazenyl radicals, obtained by one-electron reduction of the corresponding triazenyl cations with potassium metal. These radicals reversibly oxidize back to the cations upon treatment with transition metal sources or electrophiles, and abstract H atom from xanthene to form a new N-H bond at the center nitrogen atom. Potential application of the redox couple between triazenyl cation and triazenyl radical was demonstrated as cathode active materials in lithium ion batteries.116sciescopu

Activin receptor-like kinase 1 modulates transforming growth factor-β1 signaling in the regulation of angiogenesis

The activin receptor-like kinase 1 (ALK1) is a type I receptor for transforming growth factor-β (TGF-β) family proteins. Expression of ALK1 in blood vessels and mutations of the ALK1 gene in human type II hereditary hemorrhagic telangiectasia patients suggest that ALK1 may have an important role during vascular development. To define the function of ALK1 during development, we inactivated the ALK1 gene in mice by gene targeting. The ALK1 homozygous embryos die at midgestation, exhibiting severe vascular abnormalities characterized by excessive fusion of capillary plexes into cavernous vessels and hyperdilation of large vessels. These vascular defects are associated with enhanced expression of angiogenic factors and proteases and are characterized by deficient differentiation and recruitment of vascular smooth muscle cells. The blood vessel defects in ALK1-deficient mice are reminiscent of mice lacking TGF-β1, TGF-β type II receptor (TβR-II), or endoglin, suggesting that ALK1 may mediate TGF-β1 signal in endothelial cells. Consistent with this hypothesis, we demonstrate that ALK1 in endothelial cells binds to TGF-β1 and TβR-II. Furthermore, the ALK1 signaling pathway can inhibit TGF-β1-dependent transcriptional activation mediated by the known TGF-β1 type I receptor, ALK5. Taken together, our results suggest that the balance between the ALK1 and ALK5 signaling pathways in endothelial cells plays a crucial role in determining vascular endothelial properties during angiogenesis

Factors affecting rice yield and fertilizer response in rainfed lowlands of northeast Thailand

Rice-based (Oryza sativa L.) rainfed lowlands are the major cropping system in northeast Thailand. Earlier research on nutrient management of rainfed lowland rice produced conflicting results with respect to inherent soil fertility, fertilizer response, and the importance of organic fertilizers. most probably because of highly variable soil quality and water resources. The objectives of this paper were to advance the understanding of soil fertility and fertilizer response in northeast Thailand and thereby provide a basic framework for improved nutrient management of rainfed lowland rice. For this purpose, we analyzed an existing database on fertilizer trials conducted between 1995 and 1997 at eight different sites in northeast Thailand, which were previously described by Wade et al. [Wade, L.J., Amarante, S.T., Olea, A., Hampichitvitaya. D., Naklang, K., Wihardjaka, A., Sengar, S.S., Mazid, M.A., Singh, G., McLaren, C.G., 1999a. Nutrient requirements in rainfed lowland rice. Field Crops Res., 64, 91-107]. Average annual rainfall across sites and seasons was 1300 rum, but half of all rainfed trials (12 of 23) experienced substantial water stress during the growing season. Average grain yield in N-omission plots was low (1.6 t ha(-1)), even when compared with that of rainfed lowlands in neighboring Lao PDR. Nitrogen was clearly the most limiting element, whereas PK treatments increased yields significantly in only 6 out of 78 observations. Average agronomic efficiency of applied N was good ( 16 kg grain kg 1 N). but highly variable among sites. Two groups of soils (i.e., sites) were separated because of their distinct differences in reaction to inorganic and organic fertilizer. Better nutrient availability improved crop performance at all field water stress levels occurring at the trial sites. However, yield reductions caused by water stress seemed to interact with the level of nutrient supply, that is, absolute yield differences between different fertilizer treatments decreased with increasing water stress. We concluded that efficient fertilizer use in rainfed rice of northeast Thailand can be achieved, but that existing uniform recommendations do not provide farmers with much useful advice. Therefore, we proposed a set of basic guidelines for improved nutrient management, which, after further efforts of all stakeholders involved, could contribute to increased system productivity. (c) 2006 Elsevier B.V. All rights reserved