【Author】 Fraser, Emma
【影响因子】27.000
【主题类别】
区块链应用-虚拟经济-元宇宙
【Abstract】The accelerated post-Covid expansion of online worlds presents an unprecedented move of people into real-time interactive digital spaces. What does this change mean for the future of geography as a discipline? At this critical juncture, there is potential to rethink the position of the digital in geographical thought and praxis - to move beyond apparently common-sense categorizations of real and virtual, representation and reality. This commentary considers the implications of the contemporary push toward 'metaversal' thinking for geographical theory as well as the significance of virtual world-making for geographical theorizations of digital space and place. I suggest that key thinkers on space and media geographies must be re-evaluated and applied to this new wave of digital development. What is the significance of recent debates around emerging spaces like the metaverse, augmented reality, and virtual reality, understood not as happenings with distinct real and virtual counterparts, but as geographical - spatial - phenomena?
你可以尝试使用大模型来生成摘要 立即生成
【Keywords】Digital space; metaverse; video games; digital geographies; virtual worlds
【发表时间】2023
【收录时间】2023-08-05
【文献类型】 观点阐述
CCF-C
【影响因子】10.238
【主题类别】
区块链应用-实体经济-医疗领域
【Abstract】Recently, as a consequence of the coronavirus disease (COVID-19) pandemic, dependence on contact tracing (CT) models has significantly increased to prevent the spread of this highly contagious virus and be prepared for the potential future ones. Since the spreading probability of the novel coronavirus in indoor environments is much higher than that of the outdoors, there is an urgent and unmet quest to develop/design efficient, autonomous, trustworthy, and secure indoor CT solutions. Despite such an urgency, this field is still in its infancy. This article addresses this gap and proposes the trustworthy blockchain-enabled system for an indoor CT (TB-ICT) framework. The TB-ICT framework is proposed to protect privacy and integrity of the underlying CT data from unauthorized access. More specifically, it is a fully distributed and innovative blockchain platform exploiting the proposed dynamic Proof-of-Work (dPoW) credit-based consensus algorithm coupled with randomized hash window (W-Hash) and dynamic Proof-of-Credit (dPoC) mechanisms to differentiate between honest and dishonest nodes. The TB-ICT not only provides a decentralization in data replication but also quantifies the node's behavior based on its underlying credit-based mechanism. For achieving a high localization performance, we capitalize on the availability of Internet of Things (IoT) indoor localization infrastructures, and develop a data-driven localization model based on bluetooth low-energy (BLE) sensor measurements. The simulation results show that the proposed TB-ICT prevents the COVID-19 from spreading by the implementation of a highly accurate CT model while improving the users' privacy and security.
你可以尝试使用大模型来生成摘要 立即生成
【Keywords】Blockchain; bluetooth low energy (BLE); contact tracing (CT); indoor localization
【发表时间】2023
【收录时间】2023-08-05
【文献类型】 实验仿真
CCF-C
【影响因子】10.238
【主题类别】
区块链技术-核心技术-共识机制
【Abstract】The consensus algorithm is an essential ingredient of any blockchain system. Many different consensus mechanisms, such as practical Byzantine fault tolerance (PBFT), Proof-of-Work (PoW), Proof-of-Stake (PoS), and their many derivatives, have been proposed over the years, but the complementary problems of performance and resilience to malicious behavior of the nodes have yet to be resolved in a satisfactory manner. In this work, we propose a consensus mechanism that integrates PoS with PBFT, which can effectively deal with dishonest nodes, both individual validators and leaders, while maintaining high performance. Our model incentivized truthful behavior by using trust score and reward mechanisms as crucial components of the block validation and ordering processes. The performance of the proposed scheme is evaluated using an analytical model that employs a semi-Markov process, defined by an ergodic multidimensional Markov chain with a finite number of states. The results show the efficiency of the proposed model in consensus-based decision making, even under a high likelihood of dishonest node behavior.
你可以尝试使用大模型来生成摘要 立即生成
【Keywords】Blockchain; Internet of Things (IoT); practical Byzantine fault tolerance (PBFT); Proof of Stake (PoS)
【发表时间】2023
【收录时间】2023-08-05
【文献类型】 理论模型
【影响因子】8.957
【主题类别】
区块链治理-市场治理-舆情分析
【Abstract】With the rapid rise of metaverse spaces, the integration of haptic technology has become an integral part of users' immersion and engagement in different domains. This study shades the light on public engagement with haptic technology applications in various contexts. The YouTube Application Programming Interface was used to extract data about haptic technology within a specific time period. Public engagement was estimated based on users' cognitive and behavioral engagement with haptic-video materials. A topic modeling approach was used to extract the main topics associated with haptic technology. The main types of users' emotions and their word association were extracted using the association rules mining technique. The results showed that public engagement with haptic technology was mostly observed in few categories (e.g., gaming). Joy and positive sentiments were strongly associated with the extracted topics. The findings offer new insights into the tendency of utilizing haptic technology across communities. The outcomes can help industries and decision makers understand ways to improve the integration of haptic technology in according to the needs of specific domains.
你可以尝试使用大模型来生成摘要 立即生成
【Keywords】Haptic technology; Haptics; Technology and society; Sentiment analysis; Gaming
【发表时间】2023
【收录时间】2023-08-05
【文献类型】 实证数据
【Author】 Mtiraoui, Amine Boubaker, Heni BelKacem, Lotfi
【影响因子】6.143
【主题类别】
区块链治理-市场治理-价格预测
【Abstract】Bitcoin price prediction is a substantial challenge for cryptocurrency investors. This study offers an innovative scheme to predict Bitcoin returns and volatilities using a hybrid model that incorporates the autoregressive fractionally integrated moving average (ARFIMA), empirical wavelet (EW) transform, and local linear wavelet neural network (LLWNN) approaches to produce an ARFIMA-EWLLWNN model. Our methodologies integrate the advantages of the long memory model, EW decomposition technique, artificial neural network structure, and back propagation and particle swarm optimization learning algorithms. The experimental results of the optimized hybrid approach outperform some classic models by providing more accurate out-of sample forecasts over longer horizons. The model proves to be the most appropriate Bitcoin forecasting technique. Moreover, the implemented method produces smaller prediction errors than other computing techniques.
你可以尝试使用大模型来生成摘要 立即生成
【Keywords】Artificial neural networks; Bitcoin; Empirical wavelet transform; Forecast performance; Long-memory process
【发表时间】2023
【收录时间】2023-08-05
【文献类型】 实证数据
【Author】 Chintapalli, Siva Surya Narayana Paramesh, S. P. Nijaguna, G. S. Jeyaraj, Jane Rubel Angelina Subhash, P.
CCF-C
【影响因子】5.102
【主题类别】
区块链应用-实体经济-医疗领域
【Abstract】The identity management (IM) solutions are designed for facilitating and managing in digital field that identifies to perform the authentication operation which has been widely used for the real-world applications. The blockchain-based IM solutions are provided which allows the user to take the control of his or her identity. The existing blockchain-based IM models and based identified the research gap and other opportunities that will improve the present research work. Also, the information for owners who are trustworthy, traceable, secure ownership for the medical data that created seriousness in the security issues. The techniques and systems were centralized made difficult for sharing the medical data that have increased the single point of failure. The blockchain technology enabled the transparent, dependable, and auditable computing in various industries that used the decentralized network in the public ledger. The main objective is to exchange data in a safe and secure manner by using unalterable logs. To achieve and to improve the transparency, security and privacy, the verifiable digital signature with controlled blockchain enabled data records (DVS-CBDR) is introduced. Performance study of the proposed system has been assessed by a number of studies, examining throughput (170 tx/s), transaction response time (21 s), latency (5 s), memory usage (200 MB), and CPU utilization (98 Hz) which is better than patient-controlled blockchain enabled electronic health records for healthcare (PcBEHR).
你可以尝试使用大模型来生成摘要 立即生成
【Keywords】Blockchain; Digital verifiable signature; Data records; Controlled blockchain enabled data records; Identity management
【发表时间】2023
【收录时间】2023-08-05
【文献类型】 实验仿真
CCF-C
【影响因子】3.488
【主题类别】
区块链应用-实体经济-通信领域
【Abstract】The rapid development of the Internet has led to the increasingly prominent feature of openness and transparency of user information. Tor, which is used to protect personal privacy, is one of the most widely used anonymous communication systems with the largest number of users. However, there are many problems with Tor, such as: illegal transactions in the dark network disturbing social security, high communication delays, and security problems such as vulnerability to DOS attacks, man-in-the-middle attacks, and censorship attacks. In this paper, we design and implement a new anonymous communication system B-Tor based on the original Tor architecture model combined with the mainstream consortium blockchain architecture Fabric, which can trace illegal transactions by using the traceability feature of blockchain and group signature algorithm. The consensus algorithm mechanism in blockchain is utilized to improve the communication efficiency and increase the throughput of the system. The system utilizes the decentralized feature of blockchain to solve the security problem of Tor mentioned above. The system performance evaluation and security evaluation are given in this paper. The experiments show that the communication delay of B-Tor anonymous communication system is low, and in the 600s user loop test, the system successfully receives the consensus file 790629 times with 98% success rate, the highest throughput is 1352.8 TPS, and the average delay is 0.1s. It is verified through the experiments that the system can be affected less during DOS attacks and can recover the state quickly.
你可以尝试使用大模型来生成摘要 立即生成
【Keywords】Tor; Hyperledger fabric; Traceability; Security
【发表时间】2023
【收录时间】2023-08-05
【文献类型】 实验仿真
【影响因子】2.411
【主题类别】
区块链治理-元分析-主题识别
【Abstract】An immense volume of digital documents exists online and offline with content that can offer useful information and insights. Utilizing topic modeling enhances the analysis and understanding of digital documents. Topic modeling discovers latent semantic structures or topics within a set of digital textual documents. The Internet of Things, Blockchain, recommender system, and search engine optimization applications use topic modeling to handle data mining tasks, such as classification and clustering. The usefulness of topic models depends on the quality of resulting term patterns and topics with high quality. Topic coherence is the standard metric to measure the quality of topic models. Previous studies build topic models to generally work on conventional documents, and they are insufficient and underperform when applied to web content data due to differences in the structure of the conventional and HTML documents. Neglecting the unique structure of web content leads to missing otherwise coherent topics and, therefore, low topic quality. This study aims to propose an innovative topic model to learn coherence topics in web content data. We present the HTML Topic Model (HTM), a web content topic model that takes into consideration the HTML tags to understand the structure of web pages. We conducted two series of experiments to demonstrate the limitations of the existing topic models and examine the topic coherence of the HTM against the widely used Latent Dirichlet Allocation (LDA) model and its variants, namely the Correlated Topic Model, the Dirichlet Multinomial Regression, the Hierarchical Dirichlet Process, the Hierarchical Latent Dirichlet Allocation, the pseudo-document based Topic Model, and the Supervised Latent Dirichlet Allocation models. The first experiment demonstrates the limitations of the existing topic models when applied to web content data and, therefore, the essential need for a web content topic model. When applied to web data, the overall performance dropped an average of five times and, in some cases, up to approximately 20 times lower than when applied to conventional data. The second experiment then evaluates the effectiveness of the HTM model in discovering topics and term patterns of web content data. The HTM model achieved an overall 35% improvement in topic coherence compared to the LDA.
你可以尝试使用大模型来生成摘要 立即生成
【Keywords】HTML topic model; HTM; Topic modeling; Topic models comparison; LDA; HTML tags; Web content mining; Web topic modeling; Generative model
【发表时间】2023
【收录时间】2023-08-05
【文献类型】 理论模型
【DOI】 10.7717/peerj-cs.1459
【Author】 Sivasankar, C. Kumanan, T.
【影响因子】2.017
【主题类别】
区块链技术-协同技术-强化学习
【Abstract】Nowadays, autonomous mobile network (AMN) nodes are utilized in widespread distribution; thus, security issues are a large apprehension. AMN is still necessary for further developments in terms of protection and privacy. In AMN, nodes are moved randomly, and the main concern is the absence of Infrastructure and dynamic topology. Active and passive attacker nodes are extremely damaging attacks alongside the AMN, and it builds the complete networks broken and disturbs the data transmission. To solve these issues, reinforcement learning based active attack detection and blockchain technique (RLBT) to protect the data from Passive attacks in the AMN. In this approach, we use the reinforcement learning (RL) method to detect the active attacks based on packet loss, packet deviation time, packet modification, and packet miss route. This blockchain method protects the node identity and other information. Thus, the passive attacker reads the data but can't identify the original data. As a result, the blockchain method provides secure communication. The RLBT approach main significant work in AMN is to isolate the active attacker nodes and protect the node information from the passive attacker nodes. Hence, this approach provides an important security service comprising authentication, privacy, and reliability. The experimental results demonstrate that the RLBT system increases 35% the detection ratio and 17.89% throughput in the AMN. Furthermore, it minimizes the possibility of miss-detection, and the false alarm rate is less than 0.1 in the AMN.
你可以尝试使用大模型来生成摘要 立即生成
【Keywords】Active attack detection; Autonomous mobile network; Passive attack detection; Blockchain method; Reinforcement learning
【发表时间】2023
【收录时间】2023-08-05
【文献类型】 实验仿真
【Author】 Alexander, Carol Imeraj, Arben
【影响因子】1.986
【主题类别】
区块链治理-市场治理-市场分析
【Abstract】We analyse robust dynamic delta hedging of bitcoin options using a set of smile-implied and other smile-adjusted deltas that are either model-free, in the sense that they are the same for every scale-invariant stochastic and/or local volatility model, or they are based on simple regime-dependent parameterisations of local volatility. These deltas are popular with option market makers in traditional assets because they are very easy to implement. Previous empirical research on dynamic delta hedging is based solely on equity index options, but analysis of our unique data on hourly historical bitcoin option prices reveals that bitcoin implied volatility curves behave very differently from those of equity index options. For call and put options with a wide range of moneyness and with synthetic constant maturities of 10, 20 and 30 days, we compare the dynamic hedging performance of different smile-adjusted deltas over two one-year periods. We also examine the use of the perpetual contract rather than the standard futures as hedging instrument because the basis risk for the perpetual is very much smaller than it is for calendar futures. Results are presented as testable statistics of hedging error variance ratios. In certain periods the use of smile-implied hedge ratios can significantly outperform the simple Black-Scholes delta hedge, especially when using the perpetual swap as hedging instrument, where efficiency gains can exceed 30% for out-of-the-money puts, and reach an average of 15% when hedging short-term out-of-the money calls during periods when the implied volatility curve slopes upwards. The advantage of using the perpetual contract is especially evident during 2021, for the longer-term contracts for which the basis is still rather large.
你可以尝试使用大模型来生成摘要 立即生成
【Keywords】Derivatives hedging; Implied volatility curve; Perpetual contract; Robust finance; Dynamic delta hedging
【发表时间】2023
【收录时间】2023-08-05
【文献类型】 实证数据
【Author】 Morozova, Ekaterina Panov, Vladimir
【影响因子】1.497
【主题类别】
区块链治理-市场治理-价格预测
【Abstract】In this paper, we present a new bivariate model for the joint description of the Bitcoin prices and the media attention to Bitcoin. Our model is based on the class of the Levy processes and is able to realistically reproduce the jump-type dynamics of the considered time series. We focus on the low-frequency setup, which is for the Levy-based models essentially more difficult than the high-frequency case. We design a semiparametric estimation procedure for the statistical inference on the parameters and the Levy measures of the considered processes. We show that the dynamics of the market attention can be effectively modelled by the Levy processes with finite Levy measures, and propose a data-driven procedure for the description of the Bitcoin prices.
你可以尝试使用大模型来生成摘要 立即生成
【Keywords】Bitcoin; deconvolution; Levy process; low-frequency data; media attention
【发表时间】2023
【收录时间】2023-08-05
【文献类型】 实证数据
【DOI】 10.1002/asmb.2798