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In the low power wide area network, the LoRaWAN protocol adopts ALOHA type to access channel without duty cycle limited. The energy-efficient of the node and the robustness for varying traffic load are not considered in the situation which may lead to unfairness of node. To balance the energy consumption and network performance, an adaptive duty cycle medium access control (ADC-MAC) protocol is proposed...
The mainly limitation of the development of underwater Radio-Frequency-Electromagnetic (RF-EM) wireless communication is severe attenuation introduced by the seawater characteristics of high permittivity and high conductivity. Fortunately, in previous studies, it was found through experiments that the loss between two underwater antennas near seawater surface or seabed is much smaller than the higher...
Heat generation in the active region leads to high junction temperature that significantly affects electrical and optical properties, reliability and lifetime of high power diode laser arrays. It is of great importance to understand the thermal behavior to improve the devices. Compared to conduction cooling techniques, diode laser arrays packaged on microchannel heat sinks have superior capability...
The reliability is the important performance of high power semiconductor laser. Thermally accelerated ageing test is an important technology of lifetime evaluation and reliability analysis. In this study, three groups of thermally accelerated ageing tests of conduction-cooled-packaged 60W 808nm high power diode laser arrays packaged by Indium solder at constant current have been carried out. Analysis...
Thermal stress is an influential factor for the reliability of HPDL and their optical properties. Two packages of conduction-cooled-packaged 60W HPDL were selected as the study samples. In order to investigate what reflow factors influence thermo-mechanical of HPLD, a COS model is established. In reflow process and working process, hard solder package suffers higher thermal stress. Thermal stress...
With the improvement of performance and reliability, high power semiconductor lasers have been widely applied in more and more fields. Thermal management is one of the most important issues effecting the optical-electrical performance of high power semiconductor laser. Compared with liquid-cooled techniques, conduction-cooled techniques have many advantages in some special applications because it...
“Smile” in high power diode laser arrays is mainly caused by thermal stress generated during packaging processes and operation. By numerical modeling, a three-dimensional finite element model of a conduction-cooled packaged 60W high power diode laser array was established. Finite element method (FEM) was conducted to simulate and analyze the thermal and mechanical characteristic of the diode laser...
With the continuous increase of the output power of semiconductor laser array, the heat generation in the active region also increases continuously, which influences the performances and lifetime of semiconductor laser array seriously. In order to improve the performances and lifetime, understanding of the thermal behavior of high power semiconductor laser array packages and optimizing the thermal...
In SaaS model, because of adopting the “single-instance multi-tenancy”, the action of malicious tenants will greatly affect other tenants of the performance and reduce the satisfaction of them. This paper presents the credibility evaluation algorithm of tenants based on the experience. According to tenants access history, it can calculate the credibility of the tenants, assign access control rights...
To achieve the goal of e-commerce of Linyi Mall, this paper proposes an SaaS-based online mall trusted platform architecture. Platform uses SOA technology. Business lease e-commerce services required through the Internet to the online mall platform. This paper also studied the customer data security and credibility in the SaaS platform. Platform uses access control technology and information encryption...
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