scholarly journals Full Manipulation of the Power Intensity Pattern in a Large Space‐Time Digital Metasurface: From Arbitrary Multibeam Generation to Harmonic Beam Steering Scheme

2020 ◽  
Vol 532 (10) ◽  
pp. 2000321 ◽  
Author(s):  
Javad Shabanpour
Keyword(s):  
Beam Steering ◽  
Space Time ◽  
Large Space ◽  
Intensity Pattern ◽  
Power Intensity ◽  
Harmonic Beam

scholarly journals Recent advances and perspectives on space-time coding digital metasurfaces

2020 ◽  
Vol 7 ◽  
pp. 7
Author(s):  
Lei Zhang ◽  
Jun Yan Dai ◽  
Massimo Moccia ◽  
Giuseppe Castaldi ◽  
Tie Jun Cui ◽  
...  
Keyword(s):  
Wireless Communications ◽  
Beam Steering ◽  
Research Area ◽  
Space Time ◽  
Temporal Coding ◽  
Complex Field ◽  
Space Time Coding ◽  
Time Coding ◽  
Spatio Temporal ◽  
Harmonic Beam

Within the overarching framework of space-time metastructures, digital metasurfaces based on spatio-temporal coding are emerging as powerful and versatile architectures for complex field manipulations, also in view of their inherently programmable nature. Here, we provide a compact survey of our recent results and ongoing studies in this research area. Examples of field manipulations include harmonic beam steering and/or shaping and programmable nonreciprocal effects. Possible applications are abundant and range from wireless communications to radars and imaging.

scholarly journals Beam steering using optical parametric amplification in Kerr medium: a space-time analogy of parametric slow-light

2012 ◽  
Vol 20 (24) ◽  
pp. 27396 ◽  
Author(s):  
Gil Fanjoux ◽  
Eric Lantz ◽  
Jérémy Michaud ◽  
Thibaut Sylvestre
Keyword(s):  
Slow Light ◽  
Beam Steering ◽  
Space Time ◽  
Parametric Amplification ◽  
Kerr Medium ◽  
Optical Parametric Amplification ◽  
Optical Parametric ◽  
Time Analogy

Pulmonary tuberculosis space–time clustering and spatial variation in temporal trends in Portugal, 2000–2010: an updated analysis

2015 ◽  
Vol 143 (15) ◽  
pp. 3211-3219 ◽  
Author(s):  
C. AREIAS ◽  
T. BRIZ ◽  
C. NUNES
Keyword(s):  
Spatial Variation ◽  
Temporal Trends ◽  
Space Time ◽  
Percentage Change ◽  
Annual Percentage Change ◽  
Clustering Methods ◽  
Large Space ◽  
Mainland Portugal ◽  
Level Data ◽  
High Space

SUMMARYPortugal, a medium- to low-level endemic country (21·6 cases/100 000 population in 2012), has one of the highest European Union tuberculosis (TB) incidences. Although incidence is declining progressively, the country's heterogeneity in both regional endemics and their evolution suggests the importance of a better understanding of subnational epidemiology to customize TB control efforts. We aimed to update knowledge on municipality-years pulmonary TB incidence clustering, identify areas with different time trends, and show the potential of combining complementary clustering methods in control of infectious diseases. We used national surveillance municipality-level data (mainland Portugal, 2000–2010). Space–time clustering and spatial variation in temporal trends methods were applied. Space–time critical clusters identified (P < 0·001) were still the Lisbon and Oporto regions. The global incidence declined at a 5·81% mean annual percentage change, with high space–time heterogeneity and distinct time trend clusters (P < 0·001). Municipalities with incidences declining more rapidly belonged to critical areas. In particular, the Oporto trend cluster had a consistent −8·98% mean annual percentage change. Large space–time heterogeneities were identified, with critical incidences in the greater Lisbon and Oporto regions, but declining more rapidly in these regions. Oporto showed a consistent, steeper decrease and could represent a good example of local control strategy. Combining results from these approaches gives promise for prospects for infectious disease control and the design of more effective, focused interventions.

scholarly journals Phase profile of the wave function of canonical tensor model and emergence of large space–times

2021 ◽  
Author(s):  
Naoki Sasakura
Keyword(s):  
Wave Function ◽  
Saddle Point ◽  
Saddle Points ◽  
Space Time ◽  
Tensor Rank ◽  
Tensor Model ◽  
Large Space ◽  
Time Dynamics ◽  
Point Analysis ◽  
Phase Profile

In this paper, to understand space–time dynamics in the canonical tensor model of quantum gravity for the positive cosmological constant case, we analytically and numerically study the phase profile of its exact wave function in a coordinate representation, instead of the momentum representation analyzed so far. A saddle point analysis shows that Lie group symmetric space–times are strongly favored due to abundance of continuously existing saddle points, giving an emergent fluid picture. The phase profile suggests that spatial sizes grow in “time,” where sizes are measured by the tensor-geometry correspondence previously introduced using tensor rank decomposition. Monte Carlo simulations are also performed for a few small N cases by applying a re-weighting procedure to an oscillatory integral which expresses the wave function. The results agree well with the saddle point analysis, but the phase profile is subject to disturbances in a large space–time region, suggesting existence of light modes there and motivating future computations of primordial fluctuations from the perspective of canonical tensor model.

The Difficulty of Teaching Historical Landscape

2020 ◽  
pp. 378-407
Author(s):  
Antonio Pasquale Brusa
Keyword(s):  
Space Time ◽  
Educational Systems ◽  
Large Space ◽  
Historical Landscape ◽  
Set Up ◽  
Definition Of ◽  
The Invisible

Identity and anti-modernity seem the fundamental concepts consider the historical landscape in Italian schools. These concepts characterize the Italian educational systems that deal with landscape and territory. The task of teaching in this situation is that of the deconstruction of stereotypes and misconceptions. It is possible to set up a historical didactic, based on the insertion of historical landscapes in large space-time contexts, and overcome the micro-histories, which characterize most of the Italian didactic experiences. The definition of history as “science of the invisible” suggests a teaching based on a well-trained imagination, of which some examples are given.

Simultaneous control of sidelobe level and harmonic beam steering in time-modulated linear arrays

2010 ◽  
Vol 46 (3) ◽  
pp. 200 ◽  
Author(s):  
Y. Tong ◽  
A. Tennant
Keyword(s):  
Beam Steering ◽  
Sidelobe Level ◽  
Linear Arrays ◽  
Simultaneous Control ◽  
Harmonic Beam

Beam steering using spatial OPA in Kerr media: a space-time analogy of parametric slow-light

2012 ◽  
Author(s):  
Gil Fanjoux ◽  
Thibaut Sylvestre
Keyword(s):  
Slow Light ◽  
Beam Steering ◽  
Space Time ◽  
Kerr Media ◽  
Time Analogy

Bayesian dynamic modeling for large space-time datasets using Gaussian predictive processes

2011 ◽  
Vol 14 (1) ◽  
pp. 29-47 ◽  
Author(s):  
Andrew O. Finley ◽  
Sudipto Banerjee ◽  
Alan E. Gelfand
Keyword(s):  
Dynamic Modeling ◽  
Space Time ◽  
Large Space ◽  
Predictive Processes
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