1,018 research outputs found
A Trust Model Based on Service Classification in Mobile Services
Internet of Things (IoT) and B3G/4G communication are promoting the pervasive
mobile services with its advanced features. However, security problems are also
baffled the development. This paper proposes a trust model to protect the
user's security. The billing or trust operator works as an agent to provide a
trust authentication for all the service providers. The services are classified
by sensitive value calculation. With the value, the user's trustiness for
corresponding service can be obtained. For decision, three trust regions are
divided, which is referred to three ranks: high, medium and low. The trust
region tells the customer, with his calculated trust value, which rank he has
got and which authentication methods should be used for access. Authentication
history and penalty are also involved with reasons.Comment: IEEE/ACM Internet of Things Symposium (IOTS), in conjunction with
GreenCom 2010, IEEE, Hangzhou, China, December 18-20, 201
Developmental Funding and Nurturing in Colleges and Universities in the New Era: Dilemmas - Paths - Significance
Doing a good job of financial aid and education in colleges and universities can help consolidate the results of China's current poverty alleviation efforts, combining "poverty alleviation with helping the wise and the ambitious" to achieve the goal of "blood transfusion", but also "blood-creation", to help students from economically disadvantaged families successfully complete their studies, and to maintain national security and stability. To help students with family economic difficulties to successfully complete their studies, to achieve social justice, and to maintain national security and stability. This paper explores the problems faced by colleges and universities in the new era in promoting the development of financial support for people, and proposes solutions to the great significance of developmental funding. Push the funding to a more in-depth development, to help students grow and achieve success, to achieve the overall development of students
Numerical simulation of clouds and precipitation depending on different relationships between aerosol and cloud droplet spectral dispersion
The aerosol effects on clouds and precipitation in deep convective cloud systems are investigated using the Weather Research and Forecast (WRF) model with the Morrison two-moment bulk microphysics scheme. Considering positive or negative relationships between the cloud droplet number concentration (Nc) and spectral dispersion (ɛ), a suite of sensitivity experiments are performed using an initial sounding data of the deep convective cloud system on 31 March 2005 in Beijing under either a maritime (‘clean’) or continental (‘polluted’) background. Numerical experiments in this study indicate that the sign of the surface precipitation response induced by aerosols is dependent on the ɛ−Nc relationships, which can influence the autoconversion processes from cloud droplets to rain drops. When the spectral dispersion ɛ is an increasing function of Nc, the domain-average cumulative precipitation increases with aerosol concentrations from maritime to continental background. That may be because the existence of large-sized rain drops can increase precipitation at high aerosol concentration. However, the surface precipitation is reduced with increasing concentrations of aerosol particles when ɛ is a decreasing function of Nc. For the ɛ−Nc negative relationships, smaller spectral dispersion suppresses the autoconversion processes, reduces the rain water content and eventually decreases the surface precipitation under polluted conditions. Although differences in the surface precipitation between polluted and clean backgrounds are small for all the ɛ−Nc relationships, additional simulations show that our findings are robust to small perturbations in the initial thermal conditions.
Keywords: aerosol indirect effects, cloud droplet spectral dispersion, autoconversion parameterization, deep convective systems, two-moment bulk microphysics schem
Ownership Structure and Systematic Risk
This paper examines the relation between market risk, our measure for systematic risk, and ownership structure. For the overall sample ranging from 1983 to 2008, the correlation between market return and a firm\u27s specific return is related to the holdings by its institutional investors. Specifically, there is a significantly positive relationship between market risk and institutional ownership, and a significantly negative relationship between market risk and institutional concentration. The results are robust to the inclusion of other firm-specific variables such as size, leverage, and liquidity measures
Effects of Seawater Corrosion and Freeze-Thaw Cycles on Mechanical Properties of Fatigue Damaged Reinforced Concrete Beams
The effects of seawater corrosion and freeze-thaw cycles on the structural behavior of fatigue damaged reinforced concrete (FDRC) beams were experimentally studied. Results show that the residual strength of FDRC beams reduces as the fatigue load level (the ratio of maximum fatigue load to the ultimate static load) increases. The reduction in the loading capacity of FDRC beams in atmosphere environment was about 6.5% and 17.8% for given fatigue load levels of 0.2 and 0.3, respectively. However, if FDRC beams are exposed to the environment of seawater wet-dry cycles or to the environment of alternating actions of freeze-thaw and seawater immersion, as expected during the service life of RC bridge structures in coastal regions or in cold coastal regions, a more rapid reduction in the strength and stiffness of the beams is observed. The significance of an accurate simulation of working load and service condition RC bridge structures in coastal regions and cold coastal regions is highlighted
Investigation of PCB Layout Parasitics in EMI Filtering of I/O Lines
EMI filters are often utilized on I/O lines to reduce high-frequency noise from being conducted or coupled off the PCB and resulting in an EMI problem. However, layout parasitics are usually inevitable in practical circuit design, and the filtering performance may vary. In this study, the impact of the board layout on the filtering performance is investigated by |S21| measurements of sample PCB boards with different filter layouts. The finite-difference time-domain method is applied to model the boards, support the experimental work, and can be used to provide a means for conducting what-if engineering studies
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