1,072 research outputs found

    Concentration inequalities for the number of real zeros of Kac polynomials

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    We study concentration inequalities for the number of real roots of the classical Kac polynomials fn(x)=∑i=0nΟixif_{n} (x) = \sum_{i=0}^n \xi_i x^i where Οi\xi_i are independent random variables with mean 0, variance 1, and uniformly bounded (2+\ep_0)-moments. We establish polynomial tail bounds, which are optimal, for the bulk of roots. For the whole real line, we establish sub-optimal tail bounds.Comment: more references adde

    INVESTIGATION AND RESEARCH OF LANDSLIDE GEOHAZARD IN NORTH-WESTERN PART OF VIETNAM FOR THE SUSTAINABLE DEVELOPMENT OF THE TERRITORY

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    Joint Research on Environmental Science and Technology for the Eart

    Structural-acoustic modeling and analysis of an engineering machinery cab in the mid-frequency range

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    The hybrid finite element method and statistical energy method was used to study the vibro-acoustic coupling characteristics of an engineering vehicle cab. The parameters of the statistical energy method, such as modal densities, damping loss factors and coupling loss factors of substructures, were acquired by numerical and analytical methods. The acoustic-structure coupling of the cab was established based on the modal densities of substructures. The vibration and noise excitations of the cab were measured by test and the sound pressure level response of the driver’s ear was predicted. It was shown that the prediction results based on the hybrid method are in agreement with the experiments and the proposed method can be applied to predict the mid-frequency response of complex vibro-acoustic coupling systems with a moderate computational cost and accuracy

    Optimal operation of Hoa Binh reservoir for flood control on Hong-Thai Binh river system

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    In the paper the optimal operation of Hoabinh reservoir for flood control on Hong–Thai Binh river system is presented. The findings show that in the flood season in 1996 if the operation of gates and outlets of Hoa Binh reservoir was made base on the calculated release, the water level at Hanoi would be 12.3 m and the water level of Hoa Binh reservoir would be 98 m. So the calculated release from Hoabinh reservoir in August 1996 can be considered as optimal in the mean that the water level at Hanoi can be controlled and the Hoabinh reservoir still have necessary pool for controlling the next floods

    Resilience of agricultural systems facing increased salinity intrusion in deltaic coastal areas of Vietnam

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    The resilience concept has provided a new insight and approach to the conventional perspective of agricultural management by emphasizing the need to maintain a diversity of future options to adapt to inevitable and often unpredictable changes. The concept has been taken up by various academic disciplines and development sectors, yet ways to define and operationalize resilience as a measurable concept are still being developed. We contributed to this ongoing effort by implementing a subjective resilience assessment method based on farmers’ perceptions of three resilience components: (1) the sensitivity of their agricultural systems to increased salinity intrusion, (2) the capacity to recover from salinity damage, and (3) the capacity to change to other systems if salinity increases in the future. We conducted 27 in-depth interviews with local and national authorities, 11 focus group discussions, and 118 semistructured and 219 structured interviews with farmers in case study villages located along salinity transects in the Mekong Delta and at different distances to sea dikes in the Red River Delta in Vietnam in 2015-2016. Results from the subjective resilience assessment reveal that none of the agricultural systems studied systematically scored higher than the other systems on all three resilience components, implying that an increase in one resilience component by switching agricultural systems would negatively affect others. Agricultural responses to this salinity problem will influence current and long-term adaptability of the systems to future changes in salinity intrusion and other social-ecological developments in the deltas. Improving resilience components, e.g., through policies and interventions, resource allocation, and farming system changes, to sustain agricultural production or facilitate transformation to alternative systems when necessary is critically important for agricultural systems facing stress. Complementing subjective resilience assessments with qualitative data is thus crucial for understanding the drivers of resilience to improve components of resilience for agricultural systems in the respective deltas

    Complex Monge-Amp\`ere equations for plurifinely plurisubharmonic functions

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    This paper studies the complex Monge-Amp\`ere equations for F\mathcal F-plurisubharmonic functions in bounded F\mathcal F-hyperconvex domains. We give sufficient conditions for this equation to solve for measures with a singular part
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