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Department Publication Year Content Type Data Sources

61.SPHERE dynamical and spectroscopic characterization of HD142527B

Author:Claudi, R;Maire, AL;Mesa, D;Cheetham, A;Fontanive, C;Gratton, R;Zurlo, A;Avenhaus, H;Bhowmik, T;Biller, B;Boccaletti, A;Bonavita, M;Bonnefoy, M;Cascone, E;Chauvin, G;Delboulbe, A;Desidera, S;D'Orazi, V;Feautrier, P;Feldt, M;Dotti, FF;Girard, JH;Giro, E;Janson, M;Hagelberg, J;Keppler, M;Kopytova, T;Lacour, S;Lagrange, AM;Langlois, M;Lannier, J;Le Coroller, H;Menard, F;Messina, S;Meyer, M;Millward, M;Olofsson, J;Pavlov, A;Peretti, S;Perrot, C;Pinte, C;Pragt, J;Ramos, J;Rochat, S;Rodet, L;Roelfsema, R;Rouan, D;Salter, G;Schmidt, T;Sissa, E;Thebault, P;Udry, S;Vigan, A


Abstract:Aims. HD142527 is one of the most frequently studied Herbig Ae/Be stars with a transitional disk that hosts a large cavity that is up to about 100 au in radius. For this reason, it has been included in the guaranteed time observation (GTO) SpHere INfrared survey for Exoplanets (SHINE) as part of the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) at the Very Large Telescope (VLT) in order to search for low-mass companions that might explain the presence of the gap. SHINE is a large survey within about 600 young nearby stars are observed with SPHERE with the aim to constrain the occurrence and orbital properties of the giant planet population at large (>5 au) orbital separation around young stars. Methods. We used the IRDIFS observing mode of SPHERE (IRDIS short for infrared dual imaging and spectrograph plus IFS or integral field spectrograph) without any coronagraph in order to search for and characterize companions as close as 30 mas of the star. Furthermore, we present the first observations that ever used the sparse aperture mask (SAM) for SPHERE both in IRDIFS and IRDIFS_EXT modes. All the data were reduced using the dedicated SPHERE pipeline and dedicated algorithms that make use of the principal component analysis (PCA) and reference differential imaging (RDI) techniques. Results. We detect the accreting low-mass companion HD142527B at a separation of 73 mas (11.4 au) from the star. No other companions with mass greater than 10 M-J are visible in the field of view of IFS (similar to 100 au centered on the star) or in the IRDIS field of view (similar to 400 au centered on the star). Measurements from IFS, SAM IFS, and IRDIS suggest an M6 spectral type for HD142527B, with an uncertainty of one spectral subtype, compatible with an object of M = 0.11 +/- 0.06 M-circle dot and R = 0.15 +/- 0.07 R-circle dot. The determination of the mass remains a challenge using contemporary evolutionary models, as they do not account for the energy input due to accretion from infalling material. We consider that the spectral type of the secondary may also be earlier than the type we derived from IFS spectra. From dynamical considerations, we further constrain the mass to 0.26(-0.14)(+0.16) , which is consistent with both our spectroscopic analysis and the values reported in the literature. Following previous methods, the lower and upper dynamical mass values correspond to a spectral type between M2.5 and M5.5 for the companion. By fitting the astrometric points, we find the following orbital parameters: a period of P = 35 137 yr; an inclination of i = 121 130 degrees, a value of Omega = 124 135 degrees for the longitude of node, and an 68%% confidence interval of similar to 18-57 au for the separation at periapsis. Eccentricity and time at periapsis passage exhibit two groups of values: similar to 0.2-0.45 and similar to 0.45-0.7 for e, and similar to 2015-2020 and similar to 2020-2022 for T-0. While these orbital parameters might at first suggest that HD142527B is not the companion responsible for the outer disk truncation, a previous hydrodynamical analysis of this system showed that they are compatible with a companion that is able to produce the large cavity and other observed features.

62.AlGaN/GaN Metal-Insulator-Semiconductor (MIS)-HFETs Based DC-DC Boost Converters with Integrated Gate Drivers

Author:Cui, M;Bu, QL;Cai, YT;Sun, RZ;Liu, W;Wen, HQ;Lam, S;Liang, YC;Mitrovic, IZ;Taylor, S;Chalker, PR;Zhao, CZ


Abstract:This study proposed a 100 kHz, 5V/11V boost converter with an integrated gate driver for a power switching device using recessed E-mode MIS-HFETs. The integrated gate driver consisting of multi-stages DCFL (Direct-Coupled FET Logic) inverters and a buffer stage, has large input swing (up to 10 V) and wide noise margin with gate dielectric, which benefits applications requiring large gate swing without any additional drivers or level shifters. The impact of transistor size on rise times and fall times have been studied. Either buffer stage or larger width of DCFL inverter can reduce rise times from 2.4 mu s to less than 0.5 mu s at 100 kHz, so the output voltage of boost converter is increased by 10 %% at a duty cycle of 0.7. However, large buffer width can result in high gate overshoot and oscillation, indicating careful design to balance switching speed and oscillation.

63.Energy dissipation characteristics of steel coupling beams with corrugated webs

Author:Hajsadeghi, M;Zirakian, T;Keyhani, A;Naderi, R;Shahmohammadi, A


Abstract:Steel coupling beams are considered as an efficient alternative to reinforced concrete coupling beams in coupled shear wall systems. The application of corrugated webs as an alternative to flat webs with stiffeners in steel coupling beams has been lately proposed and its effective role in improving the ultimate rotation capacity of such beams has been demonstrated in published studies. However, the energy absorption characteristics of corrugated-web steel coupling beams have not been investigated. In this paper, the energy dissipation characteristics as well as cyclic performance of steel coupling beams with flat and corrugated webs are investigated through detailed numerical simulations. To this end and following the validation of the numerical simulation, numerous finite element models have been developed based on several key parameters including the flat, trapezoidal, curved, and zigzag web-plate corrugation forms, web thickness, number of corrugation half-waves, and corrugation angle. In addition to the advantages of application of corrugated webs in eliminating the web stiffeners and improving the ultimate rotation capacity in steel coupling beams, results and findings of this study demonstrate that corrugated-web steel coupling beams possess appropriate energy absorption characteristics and are capable of dissipating the input energy in a quite desirable and efficient manner. Moreover, it is shown that the energy dissipation capabilities of such coupling beams can be effectively improved via efficient design and proper adjustment of corrugation parameters. (C) 2014 Elsevier Ltd. All rights reserved.



Source:Manager' Journal,2013,Vol.


65.The design and simulation of p-type Si/SiGe Terahertz quantum cascade lasers

Author:Chen, QY;Wu, JJ;Fang, Z;Zhao, CZ


Abstract:To prolong upper state lifetime in p-type Si/Si1-xGex Terahertz quantum cascade lasers, a new active region is designed in this work. Using 6 x 6 k . p theory, the eigenvalues and wavefunctions of heavy holes and light holes are firstly calculated in a single SiGe quantum well. The design in the active region of this THz Si/Si1-xGex quantum cascade lasers is then investigated. This work presents a SiGe quantum cascade laser with about 6.84 THz emission in the diagonal transition. The calculations show that about 32 ps of the upper state lifetime and about 9 cm(-1) of optical gain are obtained, which are enhanced when compared to previous designs. (C) 2013 Elsevier Ltd. All rights reserved.

66.Implications of Sino-Japanese Rivalry in High-Speed Railways for Southeast Asia

Author:Pavlicevic, D;Kratz, A

Source:EAST ASIAN POLICY,2017,Vol.9

Abstract:China and Japan are intensively vying for high-speed rail markets in Southeast Asia. Focusing on the developments surrounding the bid for Indonesia's first high-speed rail project from Jakarta to Bandung, this paper investigates Japan and China's relative strategies, and considers the policy options available to ASEAN to manage the risks rooted in Sino-Japanese competition in the sector.

67.Big data analytics for sustainability

Author:Lv, ZH;Iqbal, R;Chang, V


Abstract:Sustainability is a paradigm for thinking about the future in which environmental, societal and economic considerations are equitable in the pursuit of an improved lifestyle. Most of the economies are developing with breakneck velocities and are becoming epicenters of unsustainable global growth. Immense utilization of natural resources, waste generation and ecological irresponsibility are the reasons for such a dire situation. Big data analytics is clearly on a penetrative path across all arenas that rely on technology. (C) 2018 Published by Elsevier B.V.

68.Exploring the Micro-Foundation of Resource-Based View: The Role of Leadership in Organizational Resource Acquisition

Author:Zhang Lin ;Zhang Xiaojun;Xi Youmin

Source:Science & Technology Progress and Policy,2016,Vol.33

Abstract:Based on resource -based view ,resource dependence theory ,entrepreneurship research ,dynamic capabilities , and other related theories ,we divided organizational resource acquisition into three stages and developed eight leader's in-fluence ways in each stage respectively .The framework we proposed provides a micro-foundation of resource-based view and contributes to understanding of leadership effectiveness .

69.2nd International Workshop on Multimedia Privacy and Security

Author:Hallman, RA;Li, SJ;Chang, V


70.When is analog? When is digital?

Author:Fischer, T


Abstract:Purpose - The purpose of this paper is to present a cybernetic way of seeing analog and digital along with a basic vocabulary for discussing assumptions underlying the use of both terms. Design/methodology/approach - Taking analog and digital not as properties of observed phenomena but as properties of observers, I ask not what is digital or analog, but what I do when I use these terms. I analyze introspectively, and report on, what I think my assumptions are when using the two terms. Findings - I develop a basic vocabulary to describe engagements that I describe as analog or digital. This vocabulary is applicable beyond technical contexts and suitable also for discussing social and creative processes. It includes a kind of observer who I call matchmaker. Research limitations/implications - The presented research is preliminary and subjective. Originality/value - While previous discussions consider analog and digital as properties of observed phenomena, they are considered here as properties of observers. The presented discussion is sufficiently abstract to account for the analog and the digital at various scales, including electronic signal processing and human interaction. The author argues that discussions of engagements described as analog or digital must account for observers of these engagements, including those who act as their matchmakers.

71.Modeling and Verification of NCL Circuits Using PAT

Author:Ma, JM;Man, KL;Lim, EG;Zhang, N;Lei, CU;Guan, SU;Jeong, TT;Seon, JK

Source:CEIS 2011,2011,Vol.15

Abstract:NULL Conventional Logic (NCL) is a Delay-Insensitive (DI) clockless paradigm and is suitable for implementing asynchronous circuits. Efficient methods of analysis are required to specify and verify such DI systems. Based on Delay Insensitive sequential Process (DISP) specification, this paper demonstrates the application of formal methods by applying Process Analysis Toolkit (PAT) to model and verify the behavior of NCL circuits. A few useful constructs are successfully modeled and verified by using PAT. The flexibility and simplicity of the coding, simulation and verification shows that PAT is effective and applicable for NCL circuit design and verification. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of [CEIS 2011]

72.FMCW Rail-mounted SAR: porting spotlight SAR imaging from MATLAB to FPGA

Author:Melnikov, A;Le Kernec, J;Gray, D


Abstract:In this work, a low-cost laptop-based radar platform derived from the MIT open courseware has been implemented. It can perform ranging, Doppler measurement and SAR imaging using MATLAB as the processor. In this work, porting the signal processing algorithms onto a FPGA platform will be addressed as well as differences between results obtained using MAT LAB and those obtained using the FPGA platform. The target FPGA platforms were a Virtex6 DSP kit and Spartan3A starter kit, the latter was also low-cost to further reduce the cost for students to access radar technology.

73.Topical treatments and photodynamic therapy for actinic keratosis of the face and scalp

Author:Foley,Kelly;Gupta,Aditya K.;Martin,George;Tweed,John A.;Villanueva,Elmer;Carviel,Jessie

Source:Cochrane Database of Systematic Reviews,2019,Vol.2019

Abstract:This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To assess the effects of topical interventions and photodynamic therapy as monotherapy or combination therapy for treatment of actinic keratoses on the face and scalp (which includes lip, face, and scalp) of immunocompetent (i.e. normal immune response) adults.

74.Advances of RRAM Devices: Resistive Switching Mechanisms, Materials and Bionic Synaptic Application

Author:Shen, ZJ;Zhao, C;Qi, YF;Xu, WY;Liu, YN;Mitrovic, IZ;Yang, L;Zhao, CZ


Abstract:Resistive random access memory (RRAM) devices are receiving increasing extensive attention due to their enhanced properties such as fast operation speed, simple device structure, low power consumption, good scalability potential and so on, and are currently considered to be one of the next-generation alternatives to traditional memory. In this review, an overview of RRAM devices is demonstrated in terms of thin film materials investigation on electrode and function layer, switching mechanisms and artificial intelligence applications. Compared with the well-developed application of inorganic thin film materials (oxides, solid electrolyte and two-dimensional (2D) materials) in RRAM devices, organic thin film materials (biological and polymer materials) application is considered to be the candidate with significant potential. The performance of RRAM devices is closely related to the investigation of switching mechanisms in this review, including thermal-chemical mechanism (TCM), valance change mechanism (VCM) and electrochemical metallization (ECM). Finally, the bionic synaptic application of RRAM devices is under intensive consideration, its main characteristics such as potentiation/depression response, short-/long-term plasticity (STP/LTP), transition from short-term memory to long-term memory (STM to LTM) and spike-time-dependent plasticity (STDP) reveal the great potential of RRAM devices in the field of neuromorphic application.



Source:Electronics World,2014,Vol.


76.Multiple strategies based orthogonal design particle swarm optimizer for numerical optimization

Author:Qin, QD;Cheng, S;Zhang, QY;Wei, YM;Shi, YH


Abstract:In the canonical partide swarm optimization (PSO), each particle updates its velocity and position by taking its historical best experience and its neighbors' best experience as exemplars and adding them together. Its performance is largely dependent on the employed exemplars. However, this learning strategy in the canonical PSO is inefficient when complex problems are being optimized. In this paper, Multiple Strategies based Orthogonal Design PSO (MSODPSO) is presented, in which the social-only model or the cognition-only model is utilized in each particle's velocity update, and an orthogonal design (OD) method is used with a small probability to construct a new exemplar in each iteration. In order to enhance the efficiency of OD method and obtain more efficient exemplar, four auxiliary vector generating strategies are designed. In addition, a global best mutation operator including non-uniform mutation and Gaussian mutation is employed to improve its global search ability. The MSODPSO can be applied to PSO with the global or local structure, yielding MSODPSO-G and MSODPSO-L algorithms, respectively. To verify the effectiveness of the proposed algorithms, a set of 24 benchmark functions in 30 and 100 dimensions are utilized in experimental studies. The proposed algorithm is also tested on a real-world economic load dispatch (ELD) problem, which is modelled as a non-convex minimization problem with constraints. The experimental results on the benchmark functions and ELD problems demonstrate that the proposed MSODPSO-G and MSODPSO-L can offer high-quality solutions. (C) 2015 Elsevier Ltd. All rights reserved.

77.Is the incipient Chinese civil society playing a role in regenerating historic urban areas? Evidence from Nanjing, Suzhou and Shanghai

Author:Verdini, G


Abstract:Urban regeneration in Western countries can count on a long-lasting tradition of experiences in which civil society has played a fundamental role in counterbalancing the system of power, resulting in profound urban governance readjustments. This has been the result of the increasing centrality of horizontal alliances between citizens and associations involved in urban affairs since the late 1960s in the West. Similar theoretical frameworks have been applied in China. However, these have frequently resulted in conceptual shortcuts that depict civil society as immature or lacking and the state as authoritarian. This paper will explore whether these categories are still entirely valid to urban regeneration in China. While the regime has traditionally prevented horizontal linkages of associations in urban governance (supporting their vertical integration to ensure a certain degree of soft control), there are signs of change. In particular, three cases of urban regeneration in historic areas will be used to discuss the changing role played by civil society in China. The ultimate goal is to examine whether horizontal linkages across groups of heterogeneous citizens are arising at the micro-level of urban governance. (C) 2015 Elsevier Ltd. All rights reserved.



Source:China Scholars Abroad,2018,Vol.


79.Open-Ended Coaxial Cable Selection for Measurement of Liquid Dielectric Properties via the Reflection Method

Author:Wang, JC;Lim, EG;Leach, MP;Wang, Z;Man, KL


Abstract:An open-ended coaxial cable is used to measure the dielectric properties of lossy liquid. The method which is based on the measurement of the reflection coefficient of the open-ended cable makes it easy to operate and postprocess. To meet the accuracy requirements, the dimensions of the coaxial cable need to be taken into consideration; therefore, it is necessary to select an appropriate coaxial cable for the measurement. This paper investigates the influence of cable dimensions on dielectric measurement accuracy. With careful choice of the coaxial cable, the relative error of calculated results can be less than 0.1%%.

80.Modelling conditional moments and correlation with the continuous hidden-threshold-skew-normal distribution

Author:Belhachemi, R;Rostan, P;Racicot, FE

Source:APPLIED ECONOMICS,2015,Vol.47

Abstract:A key issue in modelling conditional densities of returns of financial assets is the time-variation of conditional volatility. The classic econometric approach models volatility of returns with the generalized autoregressive conditional heteroscedasticity (GARCH) models where the conditional mean and the conditional volatility depend only on historical prices. We propose a new family of distributions in which the conditional distribution depends on a latent continuous factor with a continuum of states. The distribution has an interpretation in terms of a mixture distribution with time-varying mixing probabilities. The distribution parameters have economic interpretations in terms of conditional volatilities and correlations of the returns with the hidden continuous state. We show empirically that this distribution outperforms its main competitor, the mixed normal conditional distribution, in terms of capturing the stylized facts known for stock returns, namely, volatility clustering, leverage effect, skewness, kurtosis and regime dependence.
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