Remote sensing based on time variance control in configurable area partitioning

In this paper a sensor data fusion approach for characteristics field monitoring, based on time variance control model, is proposed. Distributed sensing and remote processing are the basic features of the employed architecture. In fact, in order to obtain meaningful information about the temporal and spatial variations, which characterize the field levels of some characteristics (electromagnetic, air pollution, seismic, etc), a distributed network of wireless and mobile smart-sensors has been designed.Starting from the partitioned configuration of a monitored geographic areas, this model allows to take into account the different levels of degradation over time in the sensors' performances associated with the different geographic partitions, progressively increasing the severity of the control. To this end, through the introduction of a reliability curve, a revised traditional control chart for variables is proposed.The proposed approach, further constituting an element of the scientific debate, aims to be a useful operational tool for professionals and managers employed in the environment control.

Old and ancient trees are life history lottery winners and act as evolutionary buffers against long-term environmental change

Trees can live many centuries with sustained fecundity and death is largely stochastic. We use a neutral stochastic model to examine the demographic patterns that emerge over time, across a range of population sizes and empirically observed mortality rates. A small proportion of trees (~1% at 1.5% mortality) are life-history lottery winners, achieving ages >10-20x median age. Maximum age increases with bigger populations and lower mortality rates. One quarter of trees (~24%) achieve ages that are 3-4 times greater than median age. Three age classes (Mature, Old, and Ancient) contribute unique historical diversity across complex environmental cycles. Ancient trees are an emergent property of forests that requires many centuries to generate. They radically change generation time variance and population fitness, bridging infrequent environmental cycles. These life-history lottery winners are vital to future forest dynamics and invaluable data about environmental history and individual longevity. Old-growth forests contain trees that cannot be replaced through restoration or regeneration in the near future. They simply must be protected to preserve their unique diversity.

Pseudo-Random Sequence (PRS) (Space)Time-Modulated Metasurfaces

This paper presents a novel class of (space)time-modulated metasurfaces, namely (space)time metasurfaces that are modulated by pseudo-random sequence (PRS) waveforms. In contrast to their harmonically or quasi-harmonically modulated counterparts, these metasurfaces massively alter the temporal spectrum of the waves that they process; as a result, they exhibit distinct properties and offer complementary applications. These metasurfaces are assumed here to operate in the `slow-modulation' regime, where the fixed-state time between state-transition is much larger than the transient time associated with the dispersion of the media involved, which allows safe separation of the time-variance and frequency-dispersive effects of the system. Thanks to the special properties of their modulation, which are generally assumed to have a staircase shape and to be periodic in addition to being pseudo-random, the PRS (space)time-modulated metasurfaces can perform a number of unique operations, such as spectrum spreading, interference suppression, and row/cell selection. These properties, combined with modern microwave CMOS technologies, lead to applications with unique performance or/and features, such as electromagnetic stealth, secured communication, direction of arrival estimation, and spatial multiplexing.

Influence of Sector, Budget Size and Financing on Time and Cost Management of Czech International Development Projects

Research background: This article focuses on the official Czech international development (ID) aid and the factors affecting the project success in terms of cost and time variance from the plan. As per research by Ahsan and Gunawan (2010), ID projects by Asian Development Bank are finalised within their budget, however, with delays, and the result depends on the developing country. Previous article written by the author confirmed the findings also for the Czech development aid and established that cost variance is affected by the type of implementing agencies, whereas time variance depends on the developing countries. Purpose of the article: The purpose of this article is to further analyse ID projects by the Czech Development Agency and evaluate the influence of sector topics, budget size and type of financing on the time and budget management of Czech ID projects to determine what parameters could improve the efficiency of Czech ID projects. Methods: Information on all official projects conducted from 2016 to 2019 used in this article are non-public and have been received directly from the Czech Development Agency. They are first summarised in a descriptive statistics part and then analysed by non-parametric Kruskal-Wallis test. Findings & Value added: The results show that budget size, financing type and sector topics influence the cost variance, with smaller projects financed as public procurement achieving bigger savings. For time variance, there are significant differences only between different categories of the sector topics with projects focused on the environment leading to the biggest delays.