97 research outputs found

    Semantic Communications with Ordered Importance using ChatGPT

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    This letter proposes a novel semantic communication scheme with ordered importance (SCOI) using the chat generative pre-trained transformer (ChatGPT). In the proposed SCOI scheme, ChatGPT plays the role of a consulting assistant. Given a message to be transmitted, the transmitter first queries ChatGPT to output the importance order of each word. According to the importance order, the transmitter then performs an unequal error protection transmission strategy to make the transmission of essential words more reliable. Unlike the existing semantic communication schemes, SCOI is compatible with existing source-channel separation designs and can be directly embedded into current communication systems. Our experimental results show that both the transmission bit error rate (BER) of important words and the semantic loss measured by ChatGPT are much lower than the existing communication schemes

    Identifying barriers to off-site construction using grey DEMATEL approach: case of China

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    Off-site construction (OSC) methods have been widely adopted in the construction industry around the world. However, in a lot of developing countries, the application of OSC still lags behind. Although a number of research efforts have focused on identifying the OSC barriers, they are limited to qualitative descriptions, which lacks the understanding of the interrelationships among the barriers. To address this gap, this paper proposed a methodology for identifying the OSC barriers and their cause-effect relationships. The proposed methodology is composed of three phases: (1) a comprehensive literature review and in-depth interview with the OSC industry experts, (2) questionnaire survey and focus group discussion, and (3) grey DEMATEL analysis. The proposed methodology was applied in the context of China’s construction industry. The results of the grey DEMATEL analysis provided the cause-effect relationships of the 35 identified OSC barriers, which indicated six important aspects be taken into deeper consideration, such as governmental regulations and incentives, OSC practices and experiences, as well as traditional construction method transformation. The outcomes of this study will support policymakers and OSC participants to identify the influencing OSC barriers and their interrelationships, as well as propose appropriate strategies for overcoming the barriers and broadening the OSC application

    Numerical investigation of seismic behaviour of railway embankments in cold regions

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    U ovom radu provedene su iscrpne rasprave i analize primjenom numeričkih tehnika, a s ciljem da se posve ispita seizmičko ponašanje željezničkog nasipa Qinghai-Tibet. Točnije, provedena je analiza jednodimenzionalnog ekvivalentnog linearnog odziva tla u područjima permafrosta. Na temelju toga, seizmički odziv tipičnog željezničkog nasipa dalje se ispitao nelinearnim dinamičkim proračunom metodom konačnih elemenata. To je rezultiralo određivanjem nelinearnog ponašanja tla na području permafrosta (stalno smrznuto tlo), a raspravljalo se o dinamičkom ubrzanju, brzini i pomaku nasipa te se predvidjela približna kvantitativna ocjena. Rezultati upućuju na to da dinamički odziv nasipa ima izrazito nelinearna svojstva. Koeficijent vršnog ubrzanja tla na kruni nasipa veći je nego na prirodnoj površini tla, a označava povećanje od 73 % u odnosu na koeficijent na prirodnoj površini tla. Kada seizmički intenzitet postigne određenu vrijednost, područje plastičnosti postupno se pojavljivalo na nasipu, a postoji i kontinuirano proširenje područja plastičnosti koje je povezano s povećanjem vršnog ubrzanja ulaznog seizmičkog vala. Rezultati istraživanja mogu dati uvide i imati značajne implikacije za daljnje istraživanje hladnih područja.To investigate more fully seismic behaviour of the Qinghai-Tibet railway embankment, a comprehensive discussion and a781nalysis is conducted in this paper by applying a numerical technique. Specifically, the one dimensional equivalent linear ground response analysis was conducted in permafrost regions. On this basis, the seismic response of a typical railway embankment was further studied by applying the nonlinear dynamic finite element analysis method. As a result, nonlinear behaviour of permafrost sites was determined, and the dynamic acceleration, velocity and displacement of the embankment was discussed and the quantitative assessment was approximately estimated. The results indicate that the dynamic response of the embankment has distinct nonlinear characteristics. The peak ground acceleration coefficient at the embankment shoulder is larger than the natural ground surface, marking a 73% increase compared to the coefficient on the natural ground surface. When the seismic intensity reaches a certain value, a plastic zone gradually appears in the embankment, and a continuous extension of the plastic zone can be noted with an increase in peak acceleration of the input seismic wave. The findings of this research may provide an additional insight and have significant implications for further research of cold regions

    A Tile-Based EGPU with a Fused Universal Processing Engine and Graphics Coprocessor Cluster

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    As various applied sensors have been integrated into embedded devices, the Embedded Graphics Processing Unit (EGPU) has assumed more processing tasks, which requires an EGPU with higher performance. A tile-based EGPU is proposed that can be used in both general-purpose computing and 3D graphics rendering. With fused, scalable, and hierarchical parallelism architecture, the EGPU has the ability to address nearly 100 million vertices or fragments and achieves 1 GFLOPS per second at a clock frequency of 200 MHz. A fused and scalable architecture, constituted by Universal Processing Engine (UPE) and Graphics Coprocessor Cluster (GCC), ensures that the EGPU can adapt to various graphic processing scenes and situations, achieving more efficient rendering. Moreover, hierarchical parallelism is implemented via the UPE. Additionally, tiling brings a significant reduction in both system memory bandwidth and power consumption. A 0.18 µm technology library is used for timing and power analysis. The area of the proposed EGPU is 6.5 mm ∗ 6.5 mm, and its power consumption is approximately 349.318 mW. Experimental results demonstrate that the proposed EGPU can be used in a System on Chip (SoC) configuration connected to sensors to accelerate its processing and create a proper balance between performance and cost

    Bio-Inspired Autonomous Learning Algorithm With Application to Mobile Robot Obstacle Avoidance

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    Spiking Neural Networks (SNNs) are often considered the third generation of Artificial Neural Networks (ANNs), owing to their high information processing capability and the accurate simulation of biological neural network behaviors. Though the research for SNNs has been quite active in recent years, there are still some challenges to applying SNNs to various potential applications, especially for robot control. In this study, a biologically inspired autonomous learning algorithm based on reward modulated spike-timing-dependent plasticity is proposed, where a novel rewarding generation mechanism is used to generate the reward signals for both learning and decision-making processes. The proposed learning algorithm is evaluated by a mobile robot obstacle avoidance task and experimental results show that the mobile robot with the proposed algorithm exhibits a good learning ability. The robot can successfully avoid obstacles in the environment after some learning trials. This provides an alternative method to design and apply the bio-inspired robot with autonomous learning capability in the typical robotic task scenario

    Heat shock proteins in stabilization of spontaneously restored sinus rhythm in permanent atrial fibrillation patients after mitral valve surgery

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    A spontaneously restored sinus rhythm in permanent atrial fibrillation patients has been often observed after mitral valve (MV) surgery, but persisting duration in sinus rhythm varies from patient to patient. Heat shock proteins (Hsps) may be involved in pathogenesis of atrial fibrillation. We hypothesized that stabilization of restored sinus rhythm is associated with expression of Hsps in the atria. To test this hypothesis, clinical data, biopsies of right atrial appendage, and blood samples were collected from 135 atrial fibrillation patients who spontaneously restored sinus rhythm after conventional isolated MV replacement. Comparison was made between patients who had recurrence of atrial fibrillation within 7 days (AF) vs. patients with persisted sinus rhythm for more than 7 days (SR). Results showed that SR patients had higher activity of heat shock transcription factor 1 (HSF1) as well as upregulated expressions of heat shock cognate 70, Hsp70, and Hsp27 in the tissues. The activation of HSF1–Hsps pathway was associated with less-aggressive pathogenesis as reflected by lower rates of myolysis, apoptosis, interstitial fibrosis, and inflammation in SR patients. However, Hsp60 was lower in both tissue and plasma in SR patients, and was positively correlated with apoptosis, interstitial fibrosis, and inflammation. These findings suggest that the Hsps play important roles in stabilization of restored sinus rhythm after MV surgery by inhibiting AF-related atrial remodeling and arrhythmogenic substrates in atrial fibrillation patients. Low circulating Hsp60 levels preoperatively might predict a stable spontaneously restored sinus rhythm postoperatively

    Optimizing the Spectrum and Power Allocation for D2D-Enabled Communication Systems Using DC Programming

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    Device to device (D2D) communication has recently attracted a lot of attentions since it can significantly improve the system throughput and reduce the energy consumption. Indeed, the devices can communicate with each other in a D2D system, and the base station (BS) can share the spectrum with D2D users, which can efficiently improve the spectrum and energy efficiency. Nevertheless, spectrum sharing also raises the difficulty of resource allocation owing to the serious cochannel interference. To reduce the interference, the transmit power of the D2D pairs and BS to cellular users should be further optimized. In this paper, we consider the resource allocation problem of D2D networks involving the power allocation and subcarrier assignment. The resource allocation problem is formulated as a mixed integer programming problem which is difficult to solve. To reduce the computational complexity, the original problem is decomposed as two subproblems in terms of the subcarrier assignment and power allocation. For the subcarrier assignment problem, the particle swarm optimization (PSO) is adopted to solve it since the subcarrier assignment is an integer optimization problem, and it is difficult to be tackled using the traditional optimization approach. When the subcarrier assignment is fixed, there are only the power allocation variables in the original resource allocation problem. The difference of convex functions (DC) programming is adopted to solve the power allocation problem. Simulation results demonstrate the effectiveness of the proposed resource allocation scheme of D2D networks
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