On the Equivalence of Observation Structures for Petri Net Generators

Observation structures considered for Petri net generators usually assume that the firing of transitions may be observed through a static mask and that the marking of some places may be measurable. These observation structures, however, are rather limited, namely they do not cover all cases of practical interest where complex observations are possible. We consider in this paper more general ones, by correspondingly defining two new classes of Petri net generators: labeled Petri nets with outputs (LPNOs) and adaptive labeled Petri nets (ALPNs). To compare the modeling power of different Petri net generators, the notion of observation equivalence is proposed. ALPNs are shown to be the class of bounded generators possessing the highest modeling power. Looking for bridges between the different formalisms, we first present a general procedure to convert a bounded LPNO into an equivalent ALPN or even into an equivalent labeled Petri net (if any exists). Finally, we discuss the possibility of converting an unbounded LPNO into an equivalent ALPN

Performance of Machine Learning Aided Fluid Antenna System with Improved Spatial Correlation Model

Fluid antenna has emerged as a new antenna technology that enables software-controllable position reconfigurability for great diversity and multiplexing benefits. The performance of fluid antenna systems has recently been studied for single and multiuser environments adopting a generalized spatial correlation model that accounts for the channel correlation between the ports of the fluid antenna. The recent work [1] further devised machine learning algorithms to select the best port of fluid antenna in a more practical setting in which only a small number of ports is observable in the selection process, and found that extraordinary outage probability performance can be obtained. However, there is a concern of how the spatial correlation parameters are set to reflect the actual correlation structure for accurately evaluating the system performance. In this paper, the method in [2] is used to set the correlation parameter so that the model can accurately characterize the correlation amongst the ports of a fluid antenna in a given space. This paper revisits the port selection problem for single-user fluid antenna system where learning-based algorithms are employed to select the best port when only a small subset of the channel ports are known. The new results demonstrate that the impact of spatial correlation on the performance becomes more pronounced but the machine learning aided fluid antenna system is still able to match the performance of maximum ratio combining (MRC) system with many uncorrelated antennas

Interactions of soil moisture and plant community properties in meadows restored from abandoned farmlands on the Sanjiang Plain, China

Abstract Soil moisture is a major driving force of plant community succession in restored meadows. Existing studies mainly focus on diversity-productivity relationships. However, studies which determine the effects of soil moisture on the plant community properties in restored meadows are lacking. In this study, we conducted a chronosequence analysis of the interactions between soil water content variation and plant community properties in meadows following passive restoration (3-, 5-, 9-, 14-, 17-, 21-year restoration) of abandoned farmlands on the Sanjiang Plain, China. Results showed that the plant community was characterized by ruderal plants in the initial year of succession, and then by perennial plants such as Calamagrostis angustifolia and Carex spp. in older restored meadows. Similarity of restored community to target site increased across succession time whereas species diversity gradually decreased. Plant height, coverage and biomass increased with restoration time, with plant density being the exception. The community height, coverage and root/shoot ratio were positively related to the water content in the surface soil layer (0–10 cm). Conversely, plant density was significantly and negatively related with soil moisture at 0–10 cm soil depth. Plant diversity (Shannon index, Richness index and evenness) was closely correlated to soil water content at the soil depth of 0–10 cm. Our findings indicate that vegetation of cultivated meadows could be effectively restored by passive restoration. Change of plant species diversity is an especially important response to hydrological recovery in restored meadows on the Sanjiang Plain

A Vision to Smart Radio Environment: Surface Wave Communication Superhighways

IEEE Complementary to traditional approaches that focus on transceiver design for bringing the best out of unstable, lossy fading channels, one radical development in wireless communications that has recently emerged is to pursue a smart radio environment by using software-defined materials or programmable metasurfaces for establishing favorable propagation conditions. This article portraits a vision of communication superhighways enabled by surface wave (SW) propagation on intelligent surfaces for future smart radio environments. The concept differs from the mainstream efforts of using passive elements on a large surface for bouncing off radio waves intelligently toward intended user terminals. In the proposed SW vision, energy efficiency can be much higher, due to more desirable propagation characteristics compared to open-space radio propagation. The fact that SW is inherently confined to the smart surface not only greatly simplifies the task of interference management, but also makes possible exceptionally localized high-speed interference-less data access. We shall outline the opportunities and challenges arising from the SW paradigm. We shall also attempt to shed light on several key enabling technologies that make this realizable. One important technology which will be discussed is a software-controlled fluidic waveguiding architecture that permits dynamic creation of high-throughput data highways

Structural and molecular basis of the assembly of the TRPP2/PKD1 complex

Mutations in PKD1 and TRPP2 account for nearly all cases of autosomal dominant polycystic kidney disease (ADPKD). These 2 proteins form a receptor/ion channel complex on the cell surface. Using a combination of biochemistry, crystallography, and a single-molecule method to determine the subunit composition of proteins in the plasma membrane of live cells, we find that this complex contains 3 TRPP2 and 1 PKD1. A newly identified coiled-coil domain in the C terminus of TRPP2 is critical for the formation of this complex. This coiled-coil domain forms a homotrimer, in both solution and crystal structure, and binds to a single coiled-coil domain in the C terminus of PKD1. Mutations that disrupt the TRPP2 coiled-coil domain trimer abolish the assembly of both the full-length TRPP2 trimer and the TRPP2/PKD1 complex and diminish the surface expression of both proteins. These results have significant implications for the assembly, regulation, and function of the TRPP2/PKD1 complex and the pathogenic mechanism of some ADPKD-producing mutations

Genome-wide detection of Ty1-copia and Ty3-gypsy group retrotransposons in Japanese apricot (Prunus mume Sieb. et Zucc.)

The conserved domains of reverse transcriptase (RT) genes of approximately 260 bp for Ty1-copia and 430 bp for Ty3-gypsy groups of long terminal repeat (LTR) retrotransposons were amplified fromJapanese apricot (Prunus mume Sieb. et Zucc.) using degenerate oligonucleotide primers. Sequence analysis showed that 32.3% of Ty1-copia and 27.5% of Ty3-gypsy RT sequences possessed stop codons and/or frameshifts, and all sequences were AT-rich. Ty1-copia retrotransposon has higher heterogeneity than Ty3-gypsy retrotransposon, but the latter has a higher copy number revealed bysouthern dot blot hybridization. Phylogenetic analysis illustrated that some of the clones were more closely related to the representative elements present in other plant species than to other clones of Japanese apricot. Transcription was not detected by reverse transcription-polymerase chain reaction amplification for either Ty1-copia or Ty3-gypsy retrotransposons in young leaves of plants treated with UV light and 2,4-dichlorophenoxyacetic acid either individually or in both combinations, even though the ratios of dN/dS of the open reading frames among members of each subgroup of both group retrotransposons were less than 1. This is the first report on the presence of RT sequences of Ty1-copia and Ty3-gypsy group retrotransposons in Japanese apricot genome.Keywords: Prunus mume, retrotransposon, heterogeneity, copy number, transcriptional activit