42 research outputs found

    A Coefficient-Embedding Ideal Lattice can be Embedded into Infinitely Many Polynomial Rings

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    Many lattice-based crypstosystems employ ideal lattices for high efficiency. However, the additional algebraic structure of ideal lattices usually makes us worry about the security, and it is widely believed that the algebraic structure will help us solve the hard problems in ideal lattices more efficiently. In this paper, we study the additional algebraic structure of ideal lattices further and find that a given ideal lattice in some fixed polynomial ring can be embedded as an ideal in infinitely many different polynomial rings. We explicitly present all these polynomial rings for any given ideal lattice. The interesting phenomenon tells us that a single ideal lattice may have more abundant algebraic structures than we imagine, which will impact the security of corresponding crypstosystems. For example, it increases the difficulties to evaluate the security of crypstosystems based on ideal lattices, since it seems that we need consider all the polynomial rings that the given ideal lattices can be embedded into if we believe that the algebraic structure will contribute to solve the corresponding hard problem. It also inspires us a new method to solve the ideal lattice problems by embedding the given ideal lattice into another well-studied polynomial ring. As a by-product, we also introduce an efficient algorithm to identify if a given lattice is an ideal lattice or not

    How To Reorganize Social Network For Better Knowledge Contribution During Mobile Collaboration? A Study Based On Anti-Social Behavioral Perspective

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    Mobile collaboration is an emerging kind of collaboration that adopts mobile devices (i.e., laptops, PDAs, and smart phones) and social media software to improve the efficiency and productivity of collaboration. However, many collaborative teams suffer from an anti-social behavior called social loafing. Social loafing will hinder knowledge exchange within the team and further influence team performance and project outcomes. Moreover, the state of an individual’s social loafing is unobservable and changes overtime, making it difficult to be identified in real time. Therefore, our research aims to investigate the evolution of social loafing and its impact on knowledge contribution in the mobile collaboration context. We propose a machine learning model to infer individuals’ unobserved and evolving social loafing state from the series of task behaviors (quantity and quality of the contributed knowledge). Also, we explore how one’s centrality in a social network affects his/her knowledge contribution behavior when he/she is in different social loafing states. We conduct an empirical study and the results show that individuals with high or low social loafing state are very ‘sticky’ to maintain the previous state and the centrality in the network only positively influences individuals in medium social loafing state. In conclusion, our research adopts a machine leaning method to infer the evolution of individuals’ social loafing and provides a comprehensive understanding of knowledge contribution in team work

    Combined effects of tenofovir and interferon α1b on viral load and levels of peripheral regulatory T cells in chronic hepatitis B subjects

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    Purpose: To study the combined effects of tenofovir and interferon α1b on viral load and peripheral blood regulatory T cell concentrations of chronic hepatitis B (CHB) subjects. Methods: Patients with chronic hepatitis B (86 cases) were randomly assigned to two groups: control group and study group. In control subjects, tenofovir was given orally (300 mg/kg bwt/day). In addition to tenofovir, the study group received interferon α1b injection intramuscularly at a dose of 50 μg/kg thrice a week. Liver function, serum hepatitis B viral (HBV) load, and serum levels of peripheral blood regulatory T-lymphocytes were determined. Clinical effectiveness and adverse reactions in both groups were also assessed. Results: After treatment, total effectiveness was higher in the study group (86.04 %) than in control patients (62.79 %) (p < 0.05). Serum aspartate transaminase (AST), alanine aminotransferase (ALT) and total bilirubin (TBIL) significantly decreased in the study group, relative to control, but HBV DNAnegative, HbeAg-negative and HbsAg-negative cells were markedly higher in patients in the study group (p < 0.05). Moreover, there were higher CD4+ T and CD8+ T counts, and CD4+ T/CD8+ T ratio in study subjects than in control subjects (p < 0.05). Conclusion: The combination of tenofovir with interferon α1b effectively improves liver functions in patients with CHB, reduces viral load, and exerts anti-HBV effect by regulating the levels of peripheral blood T-lymphocytes

    Permanent disappearance and seasonal fluctuation of urban lake area in Wuhan, China monitored with long time series remotely sensed images from 1987 to 2016

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    Lakes are important to the healthy functioning of the urban ecosystem. The urban lakes in Wuhan, China, which is known as ‘city of hundreds of lakes’, are facing substantial threats mainly due to rapid urbanization. This paper focused on detecting the spatial and temporal change of urban lakes in Wuhan, using a long time series of Landsat and HJ-1A remotely sensed data from 1987 to 2016. The permanent disappearance and seasonal fluctuation of 28 main urban lakes were analysed, and their relationships with climatic change and human activities were discussed. The results show that most lakes in Wuhan had shrunk over the past 30 years resulting in a permanent change from water to land. The shrinkage was also most apparent in the central region of the city. Seasonal fluctuations of lake area were evident for most lakes but the relative important driving variable of lake area change varied between sub-periods of time for different lakes. The explanatory power of impervious surface to five-year permanent water change is 91.75%, suggesting that urbanization – as increasing impervious surface – had led to the shrinkage of urban lakes in Wuhan. In all, 128.28 km2 five-year permanent water disappeared from 1987 to 2016

    El papel de China en la reforma de la OMC

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    Desde su creación, la Organización Mundial del Comercio (OMC) ha desempeñado un papel insustituible en la promoción del crecimiento del comercio, la resolución de conflictos comerciales y el fomento del desarrollo económico. Pero ahora se enfrenta a graves problemas: su autoridad está disminuyendo; el unilateralismo y el proteccionismo se están extendiendo; las funciones de resolución de conflictos con la no renovación del Órgano de Apelación se están frustrando; los países miembros están recurriendo a las negociaciones de acuerdos comerciales bilaterales y plurilaterales; y la transparencia está siendo cuestionada por los países miembros. En este contexto, existe un profundo consenso dentro de la propia OMC y entre las principales economías del mundo sobre la necesidad y la urgencia de profundizar en la reforma de la OMC.China, que participade la OMC desde el 2001, y en el 2017 ya se ha convertido en la mayor nación comercial del mundo. El Libro Blanco del gobierno chino sobre China y la OMC, publicado en 2018, menciona que China es uno de los principales beneficiarios de un sistema comercial multinacional libre y abierto y un firme defensor de un sistema comercial multilateral justo y estable. Para China, la OMC ofrece una importante oportunidad de participar de forma proactiva e influir en la gobernanza internacional. Así pues, ¿cómo debería ser la participación de China en la reforma de la OMC en un momento en que ésta se enfrenta a graves problemas? ¿En qué áreas ha propuesto China reformas? ¿Cuál es la posición de los otros actores respecto de las dichas propuestas? ¿Y qué posibilidades de éxito tienen sus propuestas? Todo ello para intentar dilucidar a través de las actuales negociaciones de reforma de la OMC hasta qué punto su potencial económico y comercial se traduce en capacidad de influir en la gobernanza mundial. Responderé y analizaré estas preguntas en mi trabajo fin de máster. Con este fin, para la elaboración del trabajo se combinarán elementos de la teoría neoliberalista con la teoría constructivista u otras que sirvan para explicar la participación de China en la reforma de la OMC, en un intento de encontrar una base teórica para analizar dicha participación, contrastado con la práctica, para, mediante esta combinación sentar las bases de cara a futuras investigaciones sobre la relación de China con la OMC. Además, se han utilizado a nivel instrumental el análisis documental y el análisis comparativo para estudiar las posiciones de China respecto a las de otros países. Este TFM consta de cuatro partes. En primer lugar, a modo contextualizador, se habla de la adhesión de China a la OMC; en la segunda parte se aborda su posición actual en la OMC; en la tercera parte que forma el corpus del trabajo se señalan ejemplos de las críticas de China a la estructura vigente y se analizan las propuesta que ha presentado en los tres ámbitos de reforma estudiados; en la cuarta parte se incluyen las opiniones de otros países sobre las propuestas de China las posibles estrategias de negociación de cara a dar cierta la viabilidad de las propuestas defendidas por China.Since its creation, the World Trade Organization (WTO) has played an irreplaceable role in promoting trade growth, resolving trade disputes and fostering economic development. But it is now facing serious problems: its authority is declining; unilateralism and protectionism are spreading; dispute settlement functions -with the non-renewal of the Appellate Body are being frustrated; member countries are resorting to bilateral and plurilateral trade agreement negotiations; and transparency is being questioned by member countries. In this context, there is a deep consensus within the WTO itself and among the world's major economies on the need and urgency of deepening WTO reform. China, which has participated in the WTO since 2001, and in 2017 has already become the world's largest trading nation. The Chinese government's White Paper on China and the WTO, published in 2018, mentions that China is one of the main beneficiaries of a free and open multinational trading system and a strong advocate of a fair and stable multilateral trading system. For China, the WTO offers an important opportunity to proactively participate in and influence international governance. So, what should China's participation in WTO reform look like at a time when the WTO is facing serious problems? In what areas has China proposed reforms? What is the position of the other players with respect to these proposals? And what are the chances of their proposals succeeding? All this in an attempt to elucidate through the current WTO reform negotiations to what extent its economic and trade potential translates into capacity to influence global governance. I will answer and analyze these questions in my Master's thesis. To this end, the paper will combine elements of neoliberalist theory with constructivist or other theories that serve to explain China's participation in WTO reform, in an attempt to find a theoretical basis for analyzing such participation, contrasted with practice, in order to lay the groundwork for future research on China's relationship with the WTO through this combination. In addition, documentary analysis and comparative analysis have been used at the instrumental level to study China's positions vis-à-vis those of other countries. This Master's thesis consists of four parts. First, by way of contextualization, it discusses China's accession to the WTO; the second part deals with its current position in the WTO; the third part which forms the corpus of the work gives examples of China's criticisms of the current structure and analyzes the proposals it has presented in the three areas of reform studied; the fourth part includes the opinions of other countries on China's proposals and possible negotiation strategies in order to determine the viability of the proposals defended by China

    Measuring River Wetted Width from Remotely Sensed Imagery at the Subpixel Scale with a Deep Convolutional Neural Network

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    River wetted width (RWW) is an important variable in the study of river hydrological and biogeochemical processes. Presently, RWW is often measured from remotely sensed imagery and the accuracy of RWW estimation is typically low when coarse spatial resolution imagery is used because river boundaries often run through pixels that represent a region that is a mixture of water and land. Thus, when conventional hard classification methods are used in the estimation of RWW, the mixed pixel problem can become a large source of error. To address this problem, this paper proposes a novel approach to measure RWW at the sub‐pixel scale. Spectral unmixing is first applied to the imagery to obtain a water fraction image that indicates the proportional coverage of water in image pixels. A fine spatial resolution river map from which RWW may be estimated is then produced from the water fraction image by super‐resolution mapping (SRM). In the SRM analysis, a deep convolutional neural network (CNN) is used to eliminate the negative effects of water fraction errors and reconstruct the geographical distribution of water. The proposed approach is assessed in two experiments, with the results demonstrating that the CNN based SRM model can effectively estimate sub‐pixel scale details of rivers, and that the accuracy of RWW estimation is substantially higher than that obtained from the use of a conventional hard image classification. The improvement shows that the proposed method has great potential to derive more accurate RWW values from remotely sensed imagery

    ProAgent: Building Proactive Cooperative Agents with Large Language Models

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    Building agents with adaptive behavior in cooperative tasks stands as a paramount goal in the realm of multi-agent systems. Current approaches to developing cooperative agents rely primarily on learning-based methods, whose policy generalization depends heavily on the diversity of teammates they interact with during the training phase. Such reliance, however, constrains the agents' capacity for strategic adaptation when cooperating with unfamiliar teammates, which becomes a significant challenge in zero-shot coordination scenarios. To address this challenge, we propose ProAgent, a novel framework that harnesses large language models (LLMs) to create proactive agents capable of dynamically adapting their behavior to enhance cooperation with teammates. ProAgent can analyze the present state, and infer the intentions of teammates from observations. It then updates its beliefs in alignment with the teammates' subsequent actual behaviors. Moreover, ProAgent exhibits a high degree of modularity and interpretability, making it easily integrated into various of coordination scenarios. Experimental evaluations conducted within the Overcooked-AI environment unveil the remarkable performance superiority of ProAgent, outperforming five methods based on self-play and population-based training when cooperating with AI agents. Furthermore, in partnered with human proxy models, its performance exhibits an average improvement exceeding 10% compared to the current state-of-the-art method. For more information about our project, please visit~\url{https://pku-proagent.github.io}.Comment: v3 is the AAAI'24 camera ready version, which polished abstract and introduction based on the reviewers' comments, and enriched related works. 7 pages of main content, 2 pages of references, 2 figures and 1 tabl

    Studies on the antidiabetic activities of cordyceps militaris extract in diet-streptozotocininduced diabetic sprague-dawley rats,”

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    Due to substantial morbidity and high complications, diabetes mellitus is considered as the third "killer" in the world. A search for alternative antidiabetic drugs from herbs or fungi is highly demanded. Our present study aims to investigate the antidiabetic activities of Cordyceps militaris on diet-streptozotocin-induced type 2 diabetes mellitus in rats. Diabetic rats were orally administered with water extract or alcohol extract at 0.05 g/kg and 2 g/kg for 3 weeks, and then, the factors levels related to blood glucose, lipid, free radicals, and even nephropathy were determined. Pathological alterations on liver and kidney were examined. Data showed that, similar to metformin, Cordyceps militaris extracts displayed a significant reduction in blood glucose levels by promoting glucose metabolism and strongly suppressed total cholesterol and triglycerides concentration in serum. Cordyceps militaris extracts exhibit antioxidative effects indicated by normalized superoxide dismutase and glutathione peroxidase levels. The inhibitory effects on blood urea nitrogen, creatinine, uric acid, and protein revealed the protection of Cordyceps militaris extracts against diabetic nephropathy, which was confirmed by pathological morphology reversion. Collectively, Cordyceps militaris extract, a safe pharmaceutical agent, presents excellent antidiabetic and antinephropathic activities and thus has great potential as a new source for diabetes treatment

    Anomalous stopping of laser-accelerated intense proton beam in dense ionized matter

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    Ultrahigh-intensity lasers (1018^{18}-1022^{22}W/cm2^{2}) have opened up new perspectives in many fields of research and application [1-5]. By irradiating a thin foil, an ultrahigh accelerating field (1012^{12} V/m) can be formed and multi-MeV ions with unprecedentedly high intensity (1010^{10}A/cm2^2) in short time scale (\simps) are produced [6-14]. Such beams provide new options in radiography [15], high-yield neutron sources [16], high-energy-density-matter generation [17], and ion fast ignition [18,19]. An accurate understanding of the nonlinear behavior of beam transport in matter is crucial for all these applications. We report here the first experimental evidence of anomalous stopping of a laser-generated high-current proton beam in well-characterized dense ionized matter. The observed stopping power is one order of magnitude higher than single-particle slowing-down theory predictions. We attribute this phenomenon to collective effects where the intense beam drives an decelerating electric field approaching 1GV/m in the dense ionized matter. This finding will have considerable impact on the future path to inertial fusion energy.Comment: 8 pages, 4 figure
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