Early Transmission Dynamics and Forecasts of the Yellow Fever Outbreak in Angola, 2015-16

Introduction. Yellow fever is an infectious disease endemic in Africa and South America, and it is a vaccine-preventable disease. The outbreak of yellow fever in Angola, 2015-2016 posed a risk to the global health. In the early phase of the outbreak, mathematical modeling can be a useful tool to predicting how the outbreak might spread and what factors affect the course of the outbreak so that health policy makers and health organizations can react effectively. In this project, two mathematical models, generalized-growth model and generalized Richard model, were applied retrospectively to predict the case rises in the early phase and to forecast the short-term trend of the outbreak. Data and method. The data was extracted from the WHO weekly outbreak situation reports, for the period from Dec 04, 2015 until Sep 29, 2016. The analysis was focused on the data of 3 provinces including the capital Luanda, Huambo, and Benguela. The generalized-growth model (GGM) was applied for fitting the model into the early phase of the outbreak. GGM and the generalized Richards model (GRM) was applied for short-term forecasting the trend of the outbreak’s peak. Simulations to project the uncertainty of the epidemic trend was conducted with MATLAB R2017a (The Mathworks, Inc.). Results. Fitting GGM to the data of 3 provinces shows the patterns of case rises in the early phase widely vary from above-constant to sub-exponentially growth. Short-term forecasting with GGM becomes less capable after the epidemic reach its peak. GRM is more advantageous for the forecasting period containing the epidemic peak. However, it can be less effective when the outbreak is partly controlled or there are some interventions on the epidemic transmission. Conclusion. GGM and GRM can be the useful tool to characterize the dynamic growth of an infectious outbreak in the early phase and produce a short-term forecast of dynamic patterns that shape the guidance and action for the outbreak control and interventions

SOUND TRANSMISSION ACROSS A FINITE SIMPLY SUPPORTED DOUBLE-LAMINATED COMPOSITE PLATE WITH ENCLOSED AIR CAVITY

ABSTRACTSound transmission across a finite orthotropic laminated double-composite plate with enclosed air cavity on an infinite acoustic rigid baffle is investigated analytically. Sound velocity potential method combined with simply supported boundary conditions is used instead of traditional methods, has good scalability and is important for studies of acoustic vibration of structures. The sound transmission loss is calculated from the ratio of incident to transmitted acoustic powers. Specifically, the focus is placed on the effects of several key system parameters on sound transmission including the plate dimensions, the laminate configurations, the boundary conditions, and the composite materials are systematically examined

Enhancing Security and Robustness for SDN-Enabled Cloud Networks

Software-Defined Networking is an emerging network architecture which promises to solve the limitations associated with current cloud computing systems based on traditional network. The main idea behind SDN is to separate control plane from networking devices, thereby providing a centralized control layer integrable to cloud-based infrastructure. The integration of SDN and Cloud Computing brings an immense benefits to network deployment and management, however, this model still faces many critical challenges with regards to availability, scalability and security. In this study, we present a security and robustness SDN-Enabled Cloud model using OpenStack and OpenDaylight. In particular, we design and implement a security clustering-based SDN Controller for monitoring and managing cloud networking, and a hardware platform to accelerate packet processing in virtual switches. We evaluate our proposed model on a practical cloud testbed consisting of several physical and virtual nodes. The experiment results show that the SDN controller cluster significantly improve robustness for the network even in case of being attacked by abnormal network traffic; while the hardware-accelerated switches can be operated in highperformance and well-adapted to the cloud environment

An implementation of rotor speed observer for sensorless induction motor drive in case of machine parameter uncertainty

The paper describes observers using model reference adaptive system for sensorless induction motor drive with the pulse width modulator and the direct torque control under the circumstances of incorrect information of induction motor parameters. An approximation based on the definition of the Laplace transformation is used to obtain initial values of the parameters. These values are utilized to simulate sensorless control structures of the induction motor drive in Matlab-Simulink environment. Performance comparison of two typical observers is carried out at different speed areas and in presence of parameter uncertainty. A laboratory stand with the induction motor drive and load unit is set up to verify the properties of observers. Experimental results confirm the expected dynamic properties of selected observer

Design of freeform lens for WLEDs on the fishing boat

In this article, a free secondary lens is designed for an LED fishing/working lamp (LFWL), which is recommended for the purpose of taking the place of a traditional high-intensity discharge (HID) fishing lamp. To serve the lighting needs of fishing and the on-board activities on fishing boats, the innovative LED lamp is proposed. To make the freeform lens in our optics design process, we depended on Gaussian decomposition. In this way, it is easy to approach the targeted light intensity distribution curve (LIDC) of the LFWL lens. The simulated results show that the performance of the LED fishing/working lamps is much better than that of HID fishing lamps for illumination onboard, on the sea-surface, and underwater. Meanwhile, a lighting efficiency of 91% with the power consumption reduction of more than 50% can be achieved when the proposed LED fishing/working lamps are used instead of the HID fishing lamps

Green-emitting Gd2O2S:Tb3+ and red-emitting Y3Al5O12:Cr3+ phosphors: a suitable selection for enhancing color quality of remote phosphor structure

This article demonstrates green-emitting phosphor Gd2O2S:Tb3+ and red-emitting phosphor Y3Al5O12:Cr3+ application in the triple-layer phosphor WLED to enhance optical performance. The arrangement of phosphor layers in the WLED is red phosphor Y3Al5O12:Cr3+ on top, green phosphor Gd2O2S:Tb3+ in the middle, and yellow phosphor YAG:Ce3+ at the bottom. The principal to utilize these phosphor materials is the exploitation of additional red light component and green light component from the green and red phosphor to enrich the color rendering index (CRI) and luminous efficacy. The influences of green phosphor and red phosphor are also estimated with a new quality indicator, the color quality index (CQS). The results show red phosphor Y3Al5O12:Cr3+ enable CRI when its concentration increases while green phosphor exhibits a contrast reaction. Regarding the CQS, the optimal red phosphor concentration for CQS is from 10% to 14%, disregard the concentration in green phosphor. The improvement that applying these two phosphor materials brought comes from limiting the light loss from back-scattering and strengthen chromatic performance through addition red and green light components. These findings can support manufacturers in adapting to modern lighting requirements by improving CRI, CQS and particularly luminous efficiency to more than 40%