教学课程资源库 更多>>

关键词： Resource management   Federated learning   Vehicle-to-everything   Training   Sidelink   Reliability   3GPP   Vehicle dynamics   Computer science   Processor scheduling   Distributive training   federated learning   NR-V2X Mode 2   semi-persistent scheduling (SPS)  

摘要： The Third Generation Partnership Project (3GPP) introduced cellular vehicle-to-everything (C-V2X) for vehicular communications. In the standard, C-V2X Mode 4 is defined for the distributed resource selection. Subsequently, in 3GPP Release 16, NR-V2X is introduced with Mode 1 and Mode 2 for vehicular communications. Likewise C-V2X Mode 4, NR-V2X Mode 2 is used for decentralized resource scheduling. The vehicles select the resources based on their local observations by utilizing the semi-persistent scheduling (SPS). Since, the vehicles select the resources based on the local observation, sensing nature of SPS is challenged by the hidden node problem that lead to resource conflict. To resolve the contention, 3GPP also introduced the physical sidelink feedback channel (PSFCH) to assist the distributive resource scheduling based on the receiver feedback. However, this incurred a signaling overhead. In this work, federated learning is exploited for distributive training via offline method and distributive multiagent-based resource scheduling is performed following the principles of NR-V2X Mode 2. Distributed training favors the model accuracy by accommodating the varying affect of the environment due to the high mobile dynamics. Simulation is conducted by integrating SUMO in conjunction with 3GPP NR-V2X standard. Performance results demonstrate a substantial improvement compared to other deep learning methods, where centralized training and random resource selection procedures are employed. This research marks a significant stride toward efficient and conflict-resilient resource allocation in vehicular communications.

关键词： Measurement   Bibliometrics   Blogs   Productivity   Heating systems   Diffusion models   Data models   Computer science   Computational modeling   Volume measurement  

摘要： Assessing an institution’s research output has traditionally relied mostly on the opinion of peers, but as the field of scientometrics progressed dramatically in recent years, the evolution of quantitative indicators gained popularity and became essential. The present approaches for evaluating an institution’s research output rely on citation data, that has been quantitatively analyzed and are predominantly data-centric models. It is observed that research productivity and impact are taken into account by many ranking systems, and the measurement of research impact is mostly dependent on citation-counting techniques and the volume of research produced. The recent ranking systems evaluate the reputation of academic institutions by employing network-based algorithms, like Page Rank which examine the citation network at the institution level. An Article’s outreach and causal impact are not completely taken into consideration by the aforementioned approaches which leads to incomplete quantification of metrics. In this study, we propose a framework that uses a data-agnostic influence diffusion model to measure the academic impact of the institutions in the citation network. The diffusion model is inspired by the phenomenon of heat diffusion. The suggested framework investigates the citation trajectory for each article published by the university in the research area, analyses its influence diffusion in citation networks, and provides methods, metrics, and processes that others could apply to similar problems or datasets. By leveraging transfer entropy-based techniques, our research goes beyond citation mapping to investigate the causal link between academic influence and the reputation of publication venues employed by universities.

关键词： Blockchains   Smart contracts   Internet of Things   Uncertainty   NIST   Reliability   Security   Logic   Information technology   Computer science   Cross-chain   nonblockchain systems (NBS)   smart contract variables   uncertainty issues  

摘要： Smart contracts are essential tools for enabling interaction between blockchain and Internet of Things (IoT) systems. For example, in cold chain logistics, the blockchain can obtain the states of the logistics system through smart contracts. However, direct interactions between smart contracts and these systems introduce uncertainties, potentially leading to network forks or state inconsistencies, which can compromise the security and reliability of the blockchain. To address these challenges, a novel smart contract variable, ExState, is proposed, specifically designed to track and store the dynamic states of IoT systems. Additionally, a corresponding operational logic is defined to organize these states into sequential records, ensuring that the state sequences obtained by each node remain consistent, effectively mitigating state conflicts. In addition, a formal model is developed, accompanied by a theoretical analysis of its determinacy. Experimental results demonstrate that, in cross-chain scenarios, this method achieves a performance improvement of up to 50.41% compared to the traditional Oracle method.

关键词： Security   Authentication   Blockchains   Vehicular ad hoc networks   Privacy   Computational efficiency   Computer science   Smart contracts   Computational modeling   Elliptic curve cryptography   Authenticated key agreement (AKA)   blockchain   Internet of Vehicles (IoV)   security   trust  

摘要： The Internet of Vehicles (IoV) enhances road safety through real-time vehicle-to-vehicle (V2V) communication of traffic messages. However, V2V wireless connectivity poses security and privacy threats, as malicious adversaries can eavesdrop and modify V2V messages or compromise vehicle identity privacy. Existing authenticated key agreement (AKA) schemes attempt to address these threats but suffer from security flaws, computational inefficiency, high communication overhead, single points of failure, and trust deficits, making them unsuitable for resource-constrained and delay-sensitive IoV applications. To address the above challenges, we propose a blockchain-powered AKA scheme with a reputation-incentive mechanism (BAKARI) for V2V communication. BAKARI employs Schnorr signatures and lightweight elliptic curve cryptographic operations to improve computational efficiency, and minimizes communication overhead by completing the AKA phase with only two messages. BAKARI leverages blockchain ledger and smart contracts to maintain vehicle authentication information and V2V messages. Additionally, it incorporates a reputation-incentive model, where trustworthy vehicles are rewarded while malicious ones are penalized. A rigorous security analysis, including formal proof under the random or real model, informal analysis, and ProVerif verification, demonstrates BAKARI's resilience against security and privacy threats. Performance evaluation shows that BAKARI balances computational efficiency, communication overhead, and security better than the benchmark schemes. Finally, simulations on Hyperledger Fabric and Veins frameworks validate BAKARI's practicality in real-world IoV environments.

关键词： Black swimming dots   L929 fibroblast cell culture   Bradyrhizobium species   Cell culture contamination   16S ribosomal RNA full gene  

摘要： Introduction: Black swimming dots (BSDs) are a frequent concern for scientists performing cell culture experiments. Despite this, there is very limited literature on this phenomenon. There is one report of Achromobacter species as the causative organism of black swimming dots in cell culture. In this study, we have revealed a 16S ribosomal RNA (bacterial rrs gene) full gene-based confirmation of black swimming dots as Bradyrhizobium species in our cell culture experiments. Bradyrhizobium is primarily a soil-dwelling bacteria, carrying out nitrogen fixation in legume roots. Methodology: After inoculating the patient blood in L929 cell lines, DNA (deoxyribonucleic acid) isolation was performed on the seventh day from the trypsinized L929 cells. The culture flask under the tissue culture inverted microscope showed small moving dots in the field. The DNA extracted from the infected cell culture was then subjected to conventional PCR (Polymerase Chain Reaction) with the three sets of pan-bacterial primers targeting the full-length 16S ribosomal RNA gene. Results: Our study reveals the contamination of mammalian cell culture with the black swimming dots caused by Bradyrhizobium species bacteria. Conclusion: The 16S rRNA full gene analysis revealed that the black swimming dots in our cell culture flasks were due to Bradyrhizobium species. This study further clarifies that the BSDs in cell culture caused due to Bradyrhizobium species could not be cleared by 10 mu g/ml concentration of both the antibiotics, piperacillin and ciprofloxacin.

关键词： Internet of Things   Routing   Privacy   Publish subscribe systems   Electronic mail   Encryption   Computer science   Standards   Publish-subscribe   Computer architecture   Anonymous communications   routing   privacy   MQTT   IoT  

摘要： Message queuing telemetry transport (MQTT) is widely used as a communication primitive in publish-subscribe-based IoT applications. However, the current MQTT standard does not support the privacy of IoT devices and users. Therefore, in this paper, we address the anonymous communications for MQTT-based IoT networks by tailored onion routing. To this end, we first introduce the concept of distributed IoT broker networks, in which a collection of IoT brokers are interconnected with each other. These brokers serve as onion routers. Then, we propose a generic anonymous messaging protocol (A-MQTT) for publish-subscribe-based IoT systems. Unlike typical anonymous communications, there are multiple destination IoT devices, called subscribers, in MQTT contexts. Hence, the privacy notions, such as traceable rate, device anonymity, and path anonymity, are redesigned. To illuminate the fundamental privacy issues, closed-form approximations for these privacy metrics are modeled. In addition, simulation results demonstrate that our A-MQTT significantly improves the security performance and that our proposed models closely approximate the various privacy performance. Furthermore, a proof-of-concept protocol is implemented on a Raspberry Pi 4 in order to show that the proposed A-MQTT can be deployed in an IoT environment.

关键词： Computer science   Machine learning   Society  

摘要： Technologies that can interpret imagery have many potential applications. An innovative study of papers and patents in the field suggests one use case that overrides the others: human surveillance.

关键词： Teacher identity development   AI curriculum   Rural middle school   Latent dirichlet allocation (LDA)   STEM plus C education  

摘要： This study investigates how a CS teacher's professional identity develops during the implementation of an AI curriculum in a rural middle school. Addressing teachers' challenges with limited AI training, it focuses on identity dimensions of participation, self-categorization, and confidence. Data sources include classroom video observations and teacher interviews, analyzed using content analysis and Latent Dirichlet Allocation (LDA). The study finds that modeling, collaboration, and self-reflection strategies increase teacher participation and confidence, supporting positive self-categorization as an independent AI educator. The findings highlight the importance of targeted support to foster teacher identity development and preparedness in AI-integrated K-12 STEM + C education.