2,074 research outputs found
Exploring Downvoting in Blockchain-based Online Social Media Platforms
In recent years, Blockchain-based Online Social Media (BOSM) platforms have
evolved fast due to the advancement of blockchain technology. BOSM can
effectively overcome the problems of traditional social media platforms, such
as a single point of trust and insufficient incentives for users, by combining
a decentralized governance structure and a cryptocurrency-based incentive
model, thereby attracting a large number of users and making it a crucial
component of Web3. BOSM allows users to downvote low-quality content and aims
to decrease the visibility of low-quality content by sorting and filtering it
through downvoting. However, this feature may be maliciously exploited by some
users to undermine the fairness of the incentive, reduce the quality of highly
visible content, and further reduce users' enthusiasm for content creation and
the attractiveness of the platform. In this paper, we study and analyze the
downvoting behavior using four years of data collected from Steemit, the
largest BOSM platform. We discovered that a significant number of bot accounts
were actively downvoting content. In addition, we discovered that roughly 9% of
the downvoting activity might be retaliatory. We did not detect any significant
instances of downvoting on content for a specific topic. We believe that the
findings in this paper will facilitate the future development of user behavior
analysis and incentive pattern design in BOSM and Web3
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Printable magnesium ion quasi-solid-state asymmetric supercapacitors for flexible solar-charging integrated units.
Wearable and portable self-powered units have stimulated considerable attention in both the scientific and technological realms. However, their innovative development is still limited by inefficient bulky connections between functional modules, incompatible energy storage systems with poor cycling stability, and real safety concerns. Herein, we demonstrate a flexible solar-charging integrated unit based on the design of printed magnesium ion aqueous asymmetric supercapacitors. This power unit exhibits excellent mechanical robustness, high photo-charging cycling stability (98.7% capacitance retention after 100 cycles), excellent overall energy conversion and storage efficiency (ηoverall = 17.57%), and outstanding input current tolerance. In addition, the Mg ion quasi-solid-state asymmetric supercapacitors show high energy density up to 13.1 mWh cm-3 via pseudocapacitive ion storage as investigated by an operando X-ray diffraction technique. The findings pave a practical route toward the design of future self-powered systems affording favorable safety, long life, and high energy
Latent TGF-beta binding protein-1 plays an important role in craniofacial development
Objective: This study aims to replicate the phenotype of Ltbp1 knockout mice in zebrafish, and to address the function of LTBP1 in craniofacial development. Methods: Whole mount in situ hybridization (WISH) of ltbp1 was performed at critical periods of zebrafish craniofacial development to explore the spatial-temporal expression pattern. Furthermore, we generated morpholino based knockdown model of ltbp1 to study the craniofacial phenotype. Results: WISH of ltbp1 was mainly detected in the mandibular jaw region, brain trunk, and internal organs such as pancreas and gallbladder. And ltbp1 colocalized with both sox9a and ckma in mandibular region. Morpholino based knockdown of ltbp1 results in severe jaw malformation. Alcian blue staining revealed severe deformity of Meckel's cartilage along with the absence of ceratobranchial. Three-dimension measurements of ltbp1 morphants jaws showed decrease in both mandible length and width and increase in open mouth distance. Expression of cartilage marker sox9a and muscle marker ckma was decreased in ltbp1 morphants. Conclusions: Our experiments found that ltbp1 was expressed in zebrafish mandibular jaw cartilages and the surrounding muscles. The ltbp1 knockdown zebrafish exhibited phenotypes consistent with Ltbp1 knockout mice. And loss of ltbp1 function lead to significant mandibular jaw defects and affect both jaw cartilages and surrounding muscles
曲がり外板の加工支援フレームワークに関する研究
学位の種別: 課程博士審査委員会委員 : (主査)東京大学准教授 稗方 和夫, 東京大学教授 大和 裕幸, 東京大学教授 割澤 伸一, 東京大学准教授 白山 晋, 東京大学准教授 Moser BryanUniversity of Tokyo(東京大学
An Efficient Multi-solution Solver for the Inverse Kinematics of 3-Section Constant-Curvature Robots
Piecewise constant curvature is a popular kinematics framework for continuum
robots. Computing the model parameters from the desired end pose, known as the
inverse kinematics problem, is fundamental in manipulation, tracking and
planning tasks. In this paper, we propose an efficient multi-solution solver to
address the inverse kinematics problem of 3-section constant-curvature robots
by bridging both the theoretical reduction and numerical correction. We derive
analytical conditions to simplify the original problem into a one-dimensional
problem. Further, the equivalence of the two problems is formalised. In
addition, we introduce an approximation with bounded error so that the one
dimension becomes traversable while the remaining parameters analytically
solvable. With the theoretical results, the global search and numerical
correction are employed to implement the solver. The experiments validate the
better efficiency and higher success rate of our solver than the numerical
methods when one solution is required, and demonstrate the ability of obtaining
multiple solutions with optimal path planning in a space with obstacles.Comment: Robotics: Science and Systems 202
System-on-a-Chip Based Nano Star Tracker and Its Real-Time Image Processing Approach
The star tracker is one of the most accurate components for satellite attitude determination. With the development of the nano star tracker, it is compatible for application on small satellites. However, the drawback in dynamic property of nano star tracker has limited its extensive applications. The principal objective of this study is to introduce a system-on-a-chip (SOC) based nano star tracker with enhanced dynamic property. A morphology based image processing approach was realized based on single FPGA to achieve real-time star extraction, even from a blurred image. Such nano star tracker has been developed and tested, and field experiment results indicated that its dynamic range was up to 4°/s with a data update rate of 30Hz. Moreover, the orientation of the satellite with developed nano star tracker on board has been analyzed based on the telemetry data. Thus, such nano star tracker could promote its applications on small or agile satellites
Regulation of Vascular Endothelial Cell Polarization and Migration by Hsp70/Hsp90-Organizing Protein
Hsp70/Hsp90-organizing protein (HOP) is a member of the co-chaperone family, which directly binds to chaperones to regulate their activities. The participation of HOP in cell motility and endothelial cell functions remains largely unknown. In this study, we demonstrate that HOP is critically involved in endothelial cell migration and angiogenesis. Tube formation and capillary sprouting experiments reveal that depletion of HOP expression significantly inhibits vessel formation from endothelial cells. Wound healing and transwell migration assays show that HOP is important for endothelial cell migration. By examination of centrosome reorientation and membrane ruffle dynamics, we find that HOP plays a crucial role in the establishment of cell polarity in response to migratory stimulus. Furthermore, our data show that HOP interacts with tubulin and colocalizes with microtubules in endothelial cells. These findings indicate HOP as a novel regulator of angiogenesis that functions through promoting vascular endothelial cell polarization and migration
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