Throughput capacity of two-hop relay MANETs under finite buffers

Since the seminal work of Grossglauser and Tse [1], the two-hop relay algorithm and its variants have been attractive for mobile ad hoc networks (MANETs) due to their simplicity and efficiency. However, most literature assumed an infinite buffer size for each node, which is obviously not applicable to a realistic MANET. In this paper, we focus on the exact throughput capacity study of two-hop relay MANETs under the practical finite relay buffer scenario. The arrival process and departure process of the relay queue are fully characterized, and an ergodic Markov chain-based framework is also provided. With this framework, we obtain the limiting distribution of the relay queue and derive the throughput capacity under any relay buffer size. Extensive simulation results are provided to validate our theoretical framework and explore the relationship among the throughput capacity, the relay buffer size and the number of nodes

Combined Cooling Heating and Power System with Integration of Middle-and-low Temperature Solar Thermal Energy and Methanol Decomposition

AbstractIn this paper, a novel distributed energy system, which contains the process of mid-and-low temperature solar energy thermochemical hybridization with methanol is proposed. Through the solar energy receiver/reactor, solar thermal energy collected by a parabolic trough concentrator, at 250°C -300°C, drives the decomposition reaction of methanol into solar fuels of syngas, thus converts to chemical energy. The chemical energy of syngas releases in the combustion chamber of a micro gas turbine to drive the combined cooling heating and power systems. Extra produced solar fuel reserves a gas tank. Energy analysis and exergy analysis of the system are implemented, and the design and off-design performance of the system and the character of chemical energy storage under variable solar radiation are discussed. As a result, the primary energy ratio of the system is 76.40%, and the net solar-to-electricity rate reaches 22.56% much higher than the exited large-scale solar thermal power plant. As the solar thermochemical energy storage contained in the system, the generating efficiency becomes insensitive to the solar radiation, and thus the efficient and stable utilization of solar thermal energy is achieved at all work condition

A Global Context Mechanism for Sequence Labeling

Sequential labeling tasks necessitate the computation of sentence representations for each word within a given sentence. With the advent of advanced pretrained language models; one common approach involves incorporating a BiLSTM layer to bolster the sequence structure information at the output level. Nevertheless, it has been empirically demonstrated (P.-H. Li et al., 2020) that the potential of BiLSTM for generating sentence representations for sequence labeling tasks is constrained, primarily due to the amalgamation of fragments form past and future sentence representations to form a complete sentence representation. In this study, we discovered that strategically integrating the whole sentence representation, which existing in the first cell and last cell of BiLSTM, into sentence representation of ecah cell, could markedly enhance the F1 score and accuracy. Using BERT embedded within BiLSTM as illustration, we conducted exhaustive experiments on nine datasets for sequence labeling tasks, encompassing named entity recognition (NER), part of speech (POS) tagging and End-to-End Aspect-Based sentiment analysis (E2E-ABSA). We noted significant improvements in F1 scores and accuracy across all examined datasets

Pulsar discovery prospect of FASTA

The Five-hundred-meter Aperture Spherical radio Telescope (FAST) has discovered more than 650 new pulsars, which account for 20% of our known Galactic pulsar population. In this paper, we estimate the prospect of a pulsar survey with a radio telescope array to be planned -- the FAST Array (FASTA), consists of six "FAST-type" telescopes. Such a sensitive radio telescope array would be a powerful instrument in probing the pulsar population deep into our Galaxy as well as in nearby galaxies. We simulate the FASTA pulsar discovery prospects with different Galactic pulsar population models and instrumental parameter combinations. We find that FASTA could detect tens of thousands of canonical pulsars and well-over thousands of millisecond pulsars. We also estimate the potential yield if the FASTA is used to search for pulsars from the nearby spiral galaxy M31, and find that it would probably discover around a hundred new radio pulsars