通讯机构：
[Junwei Lu] E;Education Information Platform of Orient Science and Technology College of Hunan Agricultural University, Changsha, China
关键词：
IoT;Cloud-edge computing;Grey wolf optimizer;Genetic algorithm;Service discovery
摘要：
Cloud-edge computing is an emerging computing model based on Service Oriented Architecture that provides reliable and available cloud services as scalable resources by collaborating fog nodes on Internet of Things (IoT) environments. One of the important issues on service discovery is energy efficiency and security for existing cloud providers and fog nodes. An optimal service discovery and selection approach as an NP-Hard problem can effective on decreasing time and cost in cloud providers to achieve through maximum capacity of Quality of Service (QoS) factors. To address of the above challenges, this paper focuses on above-mentioned outcomes and presents a QoS-aware cloud-edge service discovery and selection model in IoT environment. This model is evaluated based on a hybrid multi-objective meta-heuristic algorithm based on a Grey Wolf Optimizer and a Genetic Algorithm (GWO-GA) for evaluating QoS factors as non-functional properties. The proposed model is meant to guarantee QoS factors such as the response time, energy consumption and cost factors for the service discovery and selection problem in the IoT environment. Experimental showed that the proposed method performs 30% better than the other algorithms for decreasing cost factor.
期刊：
Revista de la Facultad de Ingeniería Universidad Central de Venezuela,2016年31(8):91-99 ISSN：0798-4065
作者机构：
[Peng, Ying] Orient Science and Technology College, Hunan Agricultural University, China;[Xu, Wei] Hunan Agricultural University, China
摘要：
This paper has designed and developed information system for student work management in colleges and universities for the demand of student management work in one city. First, elaborate and analyze the demand of information system for student work management in colleges and universities, including system overview, data description, functional demand, operation condition and system performance etc, describe the design program of system and then describe external design, database design and user interface design of each module;last, introduce the functional realization of system, test each functional index of system through practical application in one university in one city. Test results have shown that the adoption of this system realizes zero distance communication between students, teachers and school, realize deep and extensive implementation of students ideological and political education work, make information management of student work more orderly, forbidden students' violation of discipline indirectly and improve the working efficiency.
摘要：
This paper estimates carbon emissions from agricultural production in China's Hunan Province during the period from 1998 to 2012. It also analyzes trends in the development of agricultural carbon emissions and the decoupling relationship between carbon emissions and the agricultural output of Hunan. In this study, emissions from two key segments of the agricultural sector were quantified: (1) crop production and (2) livestock and poultry production (singular). A combined method of principal component analysis (PCA), multiple regression analysis, and decoupling analysis was employed to assess the drivers of agricultural carbon emissions. This showed that there was a weak and unstable decoupling relationship between agricultural carbon emissions and their output value during the period of study. The PCA revealed that two main factors-urbanization rate and nitrogen fertilization per acre-explained 92.51 % of the variation in the 11 factors that affected carbon emissions from crops. Also, two main factors (i.e., agriculture per capita GDP and the ratio of beef production to total livestock production) explained 86.27 % of the variation in nine factors that affected carbon emissions from the livestock and poultry industry. Using the PCA scores as independent variables, a multiple regression analysis of carbon emissions from the crop industry and the livestock and poultry industry showed the following patterns. (1) Theoretically, given a 10 % reduction in nitrogen fertilization per acre, crop carbon emissions would decrease by 519 units. If the rate of urbanization were to increase by 1 %, crop carbon emissions would increase by 83 units; (2) similarly, a 1 % reduction in the beef: total livestock and poultry production ratio would reduce carbon emissions from that industry by 329 units, and with "agricultural per capita GDP'' growth of 1 unit, those emissions would increase by 0.354 units. The results of this study contribute to evaluating the sustainability of agricultural production in the region, and they provide a foundation of knowledge for future development of related agricultural mitigation policy and low-carbon agricultural technology.
摘要：
In this paper, the buckling behaviors of axially functionally graded and non-uniform Timoshenko beams were investigated. Based on the auxiliary function and power series, the coupled governing equations were converted into a system of linear algebraic equations. With various end conditions, the characteristic polynomial equations in the buckling loads were obtained for axially inhomogeneous beams. The lower and higher-order eigenvalues were calculated simultaneously from the multi-roots due to the fact that the derived characteristic equation was a polynomial one. The computed results were in good agreement with those analytical and numerical ones in literature.
关键词：
Electroactive biofilms;Calcium;Exoelectrogens;Electricity generation;Microbial community
摘要：
Calcium (Ca2+) plays an important role in guaranteeing the formation and structure of microbial biofilm. However, little is known regarding its influence on the structure and electron transfer properties of electroactive biofilms (EABs). In this study, advanced investigative techniques such as microscopy and electrochemistry are employed to characterize biofilm structure and electron transfer properties following growth at different Ca2+ concentrations in a bioelectrochemical system (BES). As revealed by electrochemical measurements, a lower current is obtained from the EABs formed in the presence of higher Ca2+ concentrations. The decline of the current is due to the dominance of non-active cells and non-exoelectrogens in the biofilms formed at high Ca2+ concentrations. The results of this study provide a better understanding of the effect of Ca2+ on EABs structure and thus electricity generation in BESs. (C) 2015 Elsevier B.V. All rights reserved.
作者机构：
[Liu, Yang; 吴卫国; 傅亚平] College of Food Science and Technology, Hunan Agricultural University, Changsha, China;[刘阳] Orient Science and Technology College of Hunan Agricultural University, Changsha, China
通讯机构：
College of Food Science and Technology, Hunan Agricultural University, Changsha, China
作者机构：
[李季; 钟美娥; 丁春霞] College of Science, Hunan Agriculture University, Changsha, China;[钟美娥] Orient Science and Technology College of Hunan Agricultural University, Changsha, China;[龚道新; 姚倩钰; 杨丽华; 钟美娥] College of Resource and Environment, Hunan Agricultural University, Changsha, China
通讯机构：
College of Resource and Environment, Hunan Agricultural University, Changsha, China
作者机构：
[廖卢艳] Orient Science and Technology College of Hunan Agricultural University, Changsha, Hunan, China;[蒋立文; 张喻; 吴卫国; 廖卢艳] Food Science and Technology College of Hunan Agricultural University, Changsha, Hunan, China
通讯机构：
Food Science and Technology College of Hunan Agricultural University, Changsha, Hunan, China
关键词：
periodic solution;biological rhythms;hepatitis B virus infection;coincidence degree theory
摘要：
In this paper, a periodic model for hepatitis B virus infection is proposed. The model describes the breeding of the infected cells and the periodic variation of the environment. On the basis of the continuation theorem of coincidence degree theory, a condition for the existence of a positive periodic solution to the model is established. The result can be used to explain the wave phenomenon on the density of the pathogens in patients blood and the occurrence of superinfection in hepatitis B virus infections. Copyright (c) 2014 John Wiley & Sons, Ltd.
关键词：
Nonexistence and existence;fourth-order;mixed boundary value problem;Mountain Pass lemma;discrete variational theory
摘要：
In this paper, a fourth-order nonlinear difference equation is considered. By using the critical point theory, we establish various sets of sufficient conditions of the nonexistence and existence of solutions for mixed boundary value problem and give some new results. Results obtained generalize and complement the existing ones.
