Search Results (11)

Vehicular Ad Hoc Networks (VANETs) support safety-critical and traffic-optimization applications through low-latency, reliable V2X communication. However, securing integrity and auditability with blockchain is challenging because conventional BFT-style consensus incurs high message overhead and latency. We introduce CoCoChain, a concept-aware consensus mechanism tailored to VANETs. Instead of exchanging full payloads, CoCoChain trains a sparse autoencoder (SAE) offline on raw message payloads and encodes each message into a low-dimensional concept vector; only the top-k activations are broadcast during consensus. These compact semantic digests are integrated into a practical BFT workflow with per-phase semantic checks using a cosine-similarity threshold $\theta =0.85$ (calibrated on validation data to balance detection and false positives). We evaluate CoCoChain in OMNeT++/SUMO across urban, highway, and multi-hop broadcast under congestion scenarios, measuring latency, throughput, packet delivery ratio, and Age of Information (AoI), and including adversaries that inject semantically corrupted concepts as well as cross-layer stress (RF jamming and timing jitter). Results show CoCoChain reduces consensus message overhead by up to 25% and confirmation latency by 20% while maintaining integrity with up to 20% Byzantine participants and improving information freshness (AoI) under high channel load. This work focuses on OBU/RSU semantic-aware consensus (not 6G joint sensing or multi-base-station fusion). The code, configs, and an anonymized synthetic replica of the dataset will be released upon acceptance. Full article

Multiple unmanned aerial vehicle (UAV) systems have attracted considerable research interest due to their broad applications, such as formation control. However, decentralized UAV formation faces challenges stemming from limited local observations, which may lead to consistency conflicts, and excessive communication. To address these issues, this paper proposes SemanticBC-DecAF, a decentralized adaptive formation (DecAF) framework under a leader–follower architecture, incorporating a semantic broadcast communication (SemanticBC) mechanism. The framework consists of three modules: (1) a proximal policy optimization (PPO)-based semantic broadcast module, where the leader UAV transmits semantically encoded global obstacle images to followers to enhance their perception; (2) a YOLOv5-based detection and position estimation module, enabling followers to infer obstacle locations from recovered images; and (3) a multi-agent proximal policy optimization (MAPPO)-based formation module, which fuses global and local observations to achieve adaptive formation and obstacle avoidance. Experiments in the multi-agent simulation environment MPE show that the proposed framework significantly improves global perception and formation efficiency compared with methods that rely on local observations. Full article

Cloud computing has witnessed widespread adoption across numerous sectors, primarily due to its substantial storage capacity and powerful computational resources. In this context, secure data sharing in cloud environments is critically important. Identity-based broadcast proxy re-encryption (IB-BPRE) has emerged as a promising solution; however, existing IB-BPRE schemes lack dynamic functionality—specifically, the ability to support user revocation and addition without updating re-encryption keys. Consequently, data owners must frequently reset and distribute these keys in response to user membership changes, leading to increased system complexity and communication overhead. In this paper, we propose an identity-based broadcast proxy re-encryption scheme with dynamic functionality (IB-BPRE-DF) to address this challenge. The proposed scheme utilizes a symmetric design of re-encryption keys to enable dynamic user updates while preserving a constant re-encryption key size. Furthermore, IB-BPRE-DF is constructed under the $(f,g,F)$-GDDHE assumption and achieves semantic security in the random oracle model. Performance evaluations demonstrate that IB-BPRE-DF significantly reduces both the communication overhead (by maintaining a constant size for the re-encryption key and re-encrypted ciphertext) and the computational burden (with near-zero computational cost for generating the re-encryption key) for resource-constrained users. This work provides a practical and scalable cryptographic solution for secure and efficient data sharing in dynamic cloud environments. Full article

While speakers of German have adopted many loanwords from other languages throughout history, recent diversification of language use in Germany is mainly driven by the global mobility of English. Previous research has therefore focused on various domains in which English linguistic resources are used, particularly in traditional media and social media communication. Furthermore, many studies on social media communication have also examined English language internet memes more broadly. Despite this plethora of research, little attention has been paid to how English is used in internet memes and reels produced by professional journalists in Germany. Playing a significant role in communication amongst young people, internet memes and reels are used by many German youth media organisations. In particular for youth radio stations in Germany, which have become multimedia outlets, online communication via Instagram is vital for their audience interaction. This paper examines the use of English linguistic resources in a professionally produced Instagram corpus of internet meme and reel captions produced by journalists working for one of the largest youth radio stations in Germany. Data for the analysis of Instagram content were collected as part of the larger ethnographic research project CIDoRA (funded by the European Union). For this project, a mixed methods approach was applied. Methods of data collection and analysis include linguistic ethnography both at the youth radio station and on the station’s Instagram profile page, informal interviews and 20 semi-structured interviews with journalists, and a quantitative and qualitative analysis of 980 meme and reel captions produced for the station’s Instagram profile. Since the youth radio station’s Instagram profile functions as a means of the station’s online self-advertisement, the analysis of this article also draws on a previous study by the researcher. This study analysed possible facilitating factors for the use of catachrestic and non-catachrestic anglicisms in radio station imaging (radio self-advertisement) of six German adult contemporary radio stations. The article therefore includes an analysis of the possible facilitating factors lexical field, brevity of expression, diachronic development of the pragmatic value of lexical items and semantic reasons for the use of English in Instagram content. It thereby explores the differences in anglicism use between these two media formats (radio broadcasting and social media communication) and whether possible facilitating factors for the use of English in adult contemporary radio station imaging are also facilitating factors for the use of English in meme and reel captions produced by the youth radio station. Full article

This paper presents Boundary-Aware Concurrent Queue (BACQ), a high-performance queue designed for modern GPUs, which focuses on high concurrency in massively parallel environments. BACQ operates at the warp level, leveraging intra-warp locality to improve throughput. A key to BACQ’s design is its ability to replace conflicting accesses to shared data with independent accesses to private data. It uses a ticket-based system to ensure fair ordering of operations and supports infinite growth of the head and tail across its ring buffer. The leader thread of each warp coordinates enqueue and dequeue operations, broadcasting offsets for intra-warp synchronization. BACQ dynamically adjusts operation priorities based on the queue’s state, especially as it approaches boundary conditions such as overfilling the buffer. It also uses a virtual caching layer for intra-warp communication, reducing memory latency. Rigorous benchmarking results show that BACQ outperforms the BWD (Broker Queue Work Distributor), the fastest known GPU queue, by more than 2× while preserving FIFO semantics. The paper demonstrates BACQ’s superior performance through real-world empirical evaluations. Full article

Satellite–ground communication is a critical component in the global communication system, significantly contributing to environmental monitoring, radio and television broadcasting, aerospace operations, and other domains. However, the technology encounters challenges in data transmission efficiency, due to the drastic alterations in the communication channel caused by the rapid movement of satellites. In comparison to traditional transmission methods, semantic communication (SemCom) technology enhances transmission efficiency by comprehending and leveraging the intrinsic meaning of information, making it ideal for image transmission in satellite communications. Nevertheless, current SemCom methods still struggle to adapt to varying channel conditions. To address this, we propose a SemCom transmission model based on a Channel Code-Book (CCB) for adaptive image transmission in diverse channel environments. Our model reconstructs and restores the original image by documenting fading and noise states under various channel conditions and dynamically adjusting the denoiser’s model parameters. Extensive experimental results demonstrate that our CCB model outperforms three representative baseline models, including Deep JSCC, ASCN, and WITT in various environments and task conditions, achieving an advantage of more than 10 dB under high signal-to-noise ratio conditions. Full article

The COVID-19 pandemic produced substantial and sudden changes in the reality of everyday life and in the collective construction of meaning. Questions arose: how should events occurring within an empty reality be broadcast? And, even before that, what structure is needed to make these events transmissible and interpretable, coping with the fact that they happen within a framework of lack of relationships and absolute silence? By analysing the worldwide live recording broadcast on 27 March 2020, commonly known as “the pope alone in Saint Peter’s Square during the pandemic”, this paper identifies a series of communicative solutions adopted by television. These range from making visible what should be hidden, to variously filling the emptiness by modifying the spatial colocation of the event, to an even more extreme solution, in which the emptiness remains as it is, and a rare semantic case occurs in which the sign coincides with its meaning. The latter is what I label the “pope of the rain” solution. Full article

Focusing on the diversified demands of location privacy in mobile social networks (MSNs), we propose a privacy-enhancing k-nearest neighbors search scheme over MSNs. First, we construct a dual-server architecture that incorporates location privacy and fine-grained access control. Under the above architecture, we design a lightweight location encryption algorithm to achieve a minimal cost to the user. We also propose a location re-encryption protocol and an encrypted location search protocol based on secure multi-party computation and homomorphic encryption mechanism, which achieve accurate and secure k-nearest friends retrieval. Moreover, to satisfy fine-grained access control requirements, we propose a dynamic friends management mechanism based on public-key broadcast encryption. It enables users to grant/revoke others’ search right without updating their friends’ keys, realizing constant-time authentication. Security analysis shows that the proposed scheme satisfies adaptive $\mathcal{L}$-semantic security and revocation security under a random oracle model. In terms of performance, compared with the related works with single server architecture, the proposed scheme reduces the leakage of the location information, search pattern and the user–server communication cost. Our results show that a decentralized and end-to-end encrypted k-nearest neighbors search over MSNs is not only possible in theory, but also feasible in real-world MSNs collaboration deployment with resource-constrained mobile devices and highly iterative location update demands. Full article

With the passing of the last testimonies, Holocaust remembrance and Holocaust education progressively rely on digital technologies to engage people in immersive, simulative, and even counterfactual memories of the Holocaust. This preliminary study investigates how three prominent Holocaust museums use social media to enhance the general public’s knowledge and understanding of historical and remembrance events. A mixed-method approach based on a combination of social media analytics and latent semantic analysis was used to investigate the Facebook, Twitter, Instagram, and YouTube profiles of Yad Vashem, the United States Holocaust Memorial Museum, and the Auschwitz–Birkenau Memorial and Museum. This social media analysis adopted a combination of metrics and was focused on how these social media profiles engage the public at both the page-content and relational levels, while their communication strategies were analysed in terms of generated content, interactivity, and popularity. Latent semantic analysis was used to analyse the most frequently used hashtags and words to investigate what topics and phrases appear most often in the content posted by the three museums. Overall, the results show that the three organisations are more active on Twitter than on Facebook and Instagram, with the Auschwitz–Birkenau Museum and Memorial occupying a prominent position in Twitter discourse while Yad Vashem and the United States Holocaust Memorial Museum had stronger presences on YouTube. Although the United States Holocaust Memorial Museum exhibits some interactivity with its Facebook fan community, there is a general tendency to use social media as a one-way broadcast mode of communication. Finally, the analysis of terms and hashtags revealed the centrality of “Auschwitz” as a broad topic of Holocaust discourse, overshadowing other topics, especially those related to recent events. Full article

Nowadays, the widely deployed and high performance Internet of Things (IoT) facilitates the communication between its terminal nodes. To enhance data sharing among terminal devices and ensure the recipients’ privacy protection, a few anonymous multi-recipient broadcast encryption (AMBE) proposals are recently given. Nevertheless, the majority of these AMBE proposals are only proven be securely against adaptively chosen plain-text attack (CPA) or selectively chosen ciphertext attack (CCA). Furthermore, all AMBE proposals are subjected to key escrow issue due to inherent characteristics of the ID-based public cryptography (ID-PKC), and cannot furnish secure de-duplication detection. However, for cloud storage, it is very important for expurgating duplicate copies of the identical message since de-duplication can save the bandwidth of network and storage space. To address the above problems, in the work, we present a privacy-preserving multi-receiver certificateless broadcast encryption scheme with de-duplication (PMCBED) in the cloud-computing setting based on certificateless cryptography and anonymous broadcast encryption. In comparison with the prior AMBE proposals, our scheme has the following three characteristics. First, it can fulfill semantic security notions of data-confidentiality and receiver identity anonymity, whereas the existing proposals only accomplish them by formalizing the weaker security models. Second, it achieves duplication detection of the ciphertext for the identical message encrypted with our broadcast encryption. Finally, it also avoids the key escrow problem of the AMBE schemes. Full article

This paper presents the CONCERT framework, a push/filter information consumption paradigm, based on a rule-based semantic contextual information system for tourism. CONCERT suggests a specific insight of the notion of context from a human mobility perspective. It focuses on the particular characteristics and requirements of travellers and addresses the drawbacks found in other approaches. Additionally, CONCERT suggests the use of digital broadcasting as push communication technology, whereby tourism information is disseminated to mobile devices. This information is then automatically filtered by a network of ontologies and offered to tourists on the screen. The results obtained in the experiments carried out show evidence that the information disseminated through digital broadcasting can be manipulated by the network of ontologies, providing contextualizedinformation that produces user satisfaction. Full article