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关键词： Blockchains   Security   Optimization   Costs   Internet of Things   Computer science   Australia   Blockchain   Internet of Things (IoT)   storage optimisation   distributed caching  

摘要： Distribution, security, and immutability have led to the great success of blockchain in many applications, while contributing to major increases in ledger size. The storage challenge is one of the major barriers to the adoption of blockchain in the Internet of Things (IoT), which consists of many resource constrained devices. In this paper, we propose Multi-Level Distributed Caching (MLDC) for blockchain storage optimisation which reduces data replication based on data access patterns in a decentralised manner. For storage optimisation of data-centric blockchains, MLDC introduces a hierarchical storage class (SC), in which every node is assigned to an SC with its own Access Frequency (AF) threshold based on node availability. To reduce the number of replications shared among participant nodes, each node in a SC continues to remove unaccessed data from local storage based on a threshold time determined by the AF threshold of the SC, while maintaining all block hashes for consistency. Eventually, all nodes in MLDC store the most frequently accessed data in their local storage, so MLDC effectively reduces the storage and query costs while minimising network overhead. We also analyse the security of MLDC and quantitatively evaluate its performance for both the uniform access and exponentially decaying access patterns. The evaluation was carried out on a representative blockchain simulator with 15 storage nodes. Our results from 11 hours of experiments producing 6667 blocks and 39997 transactions show good performance for MLDC. The results of the experimentation for the exponentially decaying assess pattern show that MLDC can reduce the total storage cost by 83% compared to conventional blockchain systems, while maintaining blockchain consistency and data availability with a slight increase in network overhead and query cost.

关键词： Thomas Aquinas   design arguments   evolutionary theodicy   Free Process Defense   malevolent designs   natural evil   perceiving design   teleological argument  

摘要： In this article, I first interpret and evaluate the main argument of E. V. R. Kojonen's book, The Compatibility of Evolution and Design. I then address a challenge against this argument (as well as against design arguments in general), namely, the problem of seemingly malevolent and bad designs in nature. Evolutionary theodicists commonly deal with this problem by assuming that the evolutionary process is not fully under God's control. This solution, however, is deeply problematic from the perspective of classical theism. I therefore suggest another approach to the problem, inspired by the thought of Thomas Aquinas.

关键词： Computer science capital   computing capital   Bourdieu   sociocultural theory   sociology in computing education   inclusive CS education  

摘要： The aim of this conceptual article is to provide a framework and a lens for educators in diversifying and making CS education more inclusive. In this article, we conceptualize the notion of computer science capital (CSC), which extends Bourdieu's sociological theory of capital and Archer et al.'s work on "science capital." The CSC concept was developed by contrasting the concept of science capital with a literature review on key factors affecting students' aspirations in CS. We argue that there is a need to distinguish between science capital and CSC, because the types of capital that are considered legitimate vary between the field of natural science and computer science. The CSC concept uses a sociocultural perspective on learning and can be understood as a form of symbolic capital that is influential in facilitating students' possibility to fully participate in, engage with, and form aspirations in CS. The CSC concept consists of three main components, each with associated subcomponents. We believe our CSC framework, along with the self-reflection prompts included in this article, will offer support for reflections for educators in their daily pedagogical work. By taking students' various levels of social and cultural capital into consideration, educators can plan didactic activities with a focus to strengthen students' various types of capital. This includes reflection on how implicit and explicit norms, beliefs, thoughts, expectations, values, and ideas can affect the pedagogical practices and ultimately the students. Only when we are reflective about our teaching practices can we be better positioned to construct a more inclusive teaching and learning environment.

关键词： Qualitative   teacher practice briefs   middle school   teachers   challenges   computer science   computational thinking   researchers   research and practice   practice   impacts  

摘要： Problem. K-12 teachers face many challenges when teaching a new subject like computer science (CS). They are often far removed from the research being conducted to identify evidence-driven solutions to these challenges. Likewise, researchers are also often removed from the challenges of classroom practices that teachers face when teaching CS. Research Questions. To create a collaborative process for teachers and researchers outside of a research practice partnership, we piloted a facilitated process in which CS middle school teachers and CS education researchers collaboratively created CS teacher practice briefs. Our research question for this study was: In what ways are teachers impacted by the process of creating teacher practice briefs in collaboration with researchers? Methodology. We conducted a qualitative study, using a semi-structured interview protocol to interview five teachers and three researchers to gain an understanding of how this process impacted the participants. We used thematic content analysis to identify several subthemes across our pre-established themes: motivation for teachers to participate, impacts on teachers, perceived impacts on students, and impacts on researchers. Findings. We found that the impact on teachers mirrored impacts found on teachers who engage in Research Practice Partnerships, including increased self-efficacy, expanded professional networks, and changed classroom practices. Implications. By bringing researchers and educators together with a clear focus on equity-based problems of practice in CS education, the results display a multitude of positive impacts. Teachers indicate that they are are positively impacted, researchers develop a clear understanding of realistic practices, and students are peripherally impacted through changed practices in the classroom. Therefore, the most significant contribution to advance the disciplinary understanding is the potential for this new process to decrease the gap between research and

关键词： sneaker customization   decolonization   black culture   sneaker industry   late colonization  

摘要： Epitomized by the athletic sneaker industry's lucrative mining of Black bodies and Black culture, the colonization of the racial "Other" by the forces of Western consumer culture has become a defining feature of late capitalism. However, we propose that contemporary consumer culture also offers possibilities for everyday decolonizing practices, specifically those associated with sneaker customization. Drawing on 15 interviews with racially-marginalized sneaker customizers, we explored how individuals used sneaker customization to initiate critical and creative dialogues with the sneaker industry and other late colonizing forces. We found that participants used sneaker customization to assert their humanity through: signaling their personal/group identity;articulating political subversions and solidarities;and seeking to uplift disadvantaged communities. We conclude by encouraging sport scholars to critically engage the possibilities for decolonizing politics as infused within everyday popular cultural practices.

关键词： Project portfolio risks   risk interactions   life cycle   social network analysis  

摘要： The need for enterprises to manage project portfolio risks over the life cycle has become increasingly prominent. It is essential to evaluate and manage them to achieve project portfolios and organizations' success. Unlike project risk, project portfolio risk is more complex and uncertain due to risk interactions. Risk management is unsatisfactory in project portfolios due to the lack of awareness of risk interactions and the life cycle. The purpose of this paper is to identify the critical risks of project portfolios over the life cycle considering risk interactions. We primarily verified 20 identified risks through a questionnaire survey and an expert interview method and evaluated the interactions among them using the Delphi method. Furthermore, risk interactions were analyzed using the social network analysis (SNA) methodology to determine the important risks. Finally, a comprehensive evaluation of important risks was carried out to identify critical risks according to the evaluation principles. The results identified six critical portfolio risks, two key risk contagion paths and revealed risk characteristics of different life cycle phases. This research considerably contributes to the body of knowledge pertaining to project portfolio management that will enable organizations that implement project portfolios and similar multi projects to emphasize critical risks.

关键词： evolution   fine-tuning   fitness function   fitness landscape   teleology  

摘要： The effectiveness of evolutionary algorithms is one of the issues discussed in The Compatibility of Evolution and Design, where it is argued that such algorithms are only effective when stringent preconditions are met. This article considers this issue from the perspective of computer science. It explores the properties of problems that can be effectively solved by evolutionary algorithms, and the extent to which such algorithms need to be carefully adjusted. Although there are important differences between the study of evolutionary algorithms in computer science and the study of biological evolution, it is argued that the experience of computer science can help to strengthen the claim that evolutionary mechanisms generally require a considerable degree of fine-tuning.

关键词： Astronomical instrumentation   Astronomy and astrophysics   Computer science   Machine learning  

摘要： The latest science news, in brief.

关键词： biology   design argument   Stephen Freeland   metaphors   pareidolia  

摘要： The first half of this article offers two possibilities of how the argument Kojonen makes might be vulnerable to other new developments in evolutionary science and psychology-potential broadsides that might threaten to sink the salvaged ship of design once again. Work on the development of life suggests that life is a simplification of surrounding environmental information, and therefore life does not generate new information. Second, the psychology of pareidolia suggests we find design as a bias of our information processing, rather than observing something that exists. The second half of the article offers a critique of how the metaphors we use to describe God and the world shape our approaches to solving theological and philosophical questions (particularly theodicy). I offer some organic metaphors in place of the usual mechanistic metaphors to think about how the design argument could be reformulated.

关键词： COVID-19   Informatics   Adaptation models   Semantics   Predictive models   Media   Computer science   Coronavirus disease 2019 (COVID-19)   deep collaborative filtering   knowledge graph (KG)   precautionary alert recommendation   similarity  

摘要： Filtration to optimal exactness is mandatory since the options inundate the online world. Knowledge graph embedding is extraordinarily contributing to the recommendations, but the existing knowledge graph (KG)-based recommendation methods only exploit the correlations among the preferences and stand-alone entities, without bonding the cocurricular features and tendencies of the context. Additionally, the integration of the location-based current data of coronavirus disease 2019 (COVID-19) into the KG is necessary for the recommendation of region-aware precautionary alerts to the concerned people-an essential application of the current and future Internet of Medical Things. Therefore, in this article, we propose a novel deep collaborative alert recommendation (DCA) approach to cope with the situation. Particularly, DCA collects current online data about COVID-19, purifies, and transforms them to the KG. Furthermore, it independently encapsulates the cocurricular features and tendencies of the context in the embedding space and encodes them to the independent hidden factors via a graph neural network. The bi-end hidden factors are computed via matrix factorization to infer the potential connections. Moreover, a relevance estimator and a cross transistor are configured to enhance the generalization capability of the model. Experiments on two real-world datasets are performed to evaluate the effectiveness of DCA. Results and analysis show that the proposed approach has outperformed the baseline methods with fine improvements in providing the required recommendations.