Energy Cooperation with Sleep Mechanism in Renewable Energy Assisted Cellular HetNets

The emerging fifth generation (5G) and beyond radio access networks are expected to be extremely dense and heterogeneous as compared to the current networks, involving a large number of different classes of base stations (BSs), namely macro, micro, femto and pico BSs. Among several performance requirements 5G and beyond systems aim to achieve, energy efficiency is one of the crucial requirements. In order to achieve energy-efficient design in dense heterogeneous 5G networks, various approaches in terms of resource allocation, off-loading techniques, hardware solutions and energy harvesting are being considered. In this regard, this paper develops an energy usage optimization framework in a cellular heterogeneous network (HetNet) consisting of a central macro-BS and a number of micro-BSs, equipped with renewable energy sources (RESs) such as solar panels and wind turbines. The proposed framework incorporates an energy cooperation mechanism along with a sleep mechanism (BS ON/OFF switching), in which the BSs having lean traffic are put into a sleep mode and their traffic load gets shared by the central BS. The surplus harvested energy from RESs of the sleeping BSs can then be sold back to the grid. An optimization problem for maximizing the utilization of RES and minimizing the usage of the traditional sources, such as utility and generator, is formulated and this mixed integer non-linear programming problem is solved through an interior point method. The presented results for various HetNet sizes demonstrate the significant savings in the energy cost with the proposed RES-enabled HetNet sleep mechanism model over the conventional approaches.

     

对称分支并行微通道中气液两相流的均匀性规律

采用高速摄像系统研究了对称分支形并行微通道内气液两相流及弹状气泡均匀性规律。实验中分别采用含0.3% SDS的甘油-水溶液与氮气作为液相和气相。观察到弹状流和泡状流两种流型,作出了由两相操作条件构成的流型图及流型转变线。结果表明,气泡非均匀性主要由两微通道内流体之间的相互作用、下游通道中流体动力学的反馈作用以及通道制造误差造成。随液相黏度增大,气泡均匀性变好;在高液相流量以及低气相压力下操作,气泡尺寸分布更易达到均匀。基于压力降守恒原理和微通道内气液两相流阻力模型,构建了两通道中气泡尺寸的预测模型。     

Dynamics of twin boundaries in ferromagnetic shape memory alloys

Abstract

Combined experimental and theoretical investigation of discrete twin boundary motion in ferromagnetic shape memory alloys 10M NiMnGa is presented. Motion of individual boundaries is studied through mechanical tests and pulsed magnetic field experiments. Analysis of the experimental results leads to identification of two intrinsic energy barriers that dominate twinning kinetics and possible mechanism for overcoming these barriers. At low velocities, the twinning stress property is dictated by a long range (micrometre scale) periodic potential. At higher rates, a short range (nanometre scale) potential, which is related to the periodicity of the lattice, is responsible for the transition in kinetic behaviour from slower thermally activated to faster athermal motion. These observations enable formulation of different kinetic relations that are valid at different ranges of the driving force. The derived relations show a very good fit to the experimental results, allowing quantitative extraction of fundamental nanoscale properties of the twin boundary.     

ICT and renewable energy: a way forward to the next generation telecom base stations

The tremendous growth in technology is also causing global warming due to harmful greenhouse gas emissions. The Information and Communication Technology (ICT) sector is one of the fastest growing, having the greatest impact on almost every other technology. Energy efficiency and reduction in global warming is now a desire and realization by all key players associated with this technology. Not only there is scope for energy efficiency in ICTs itself but it can also help other sectors in becoming smart i.e., energy efficient. Smart buildings, smart motors, smart logistics and smart grids are being realized with the incorporation of information and communication technologies. The ICT industry is equally aware of the potential benefits of renewable energy sources (RES) in making the future systems greener and sustainable. This is quite evident from the research that is going on towards sustainable ICT solutions, as reviewed in this paper. Not only renewable energy is applicable to large scale applications like telecom base stations (BS), it is also applicable to small and medium scale systems and devices like computer peripherals and electric vehicles. In order to explore the evident potential of RES, all aspects of renewable energy are being addressed by the researchers. These aspects can broadly be categorized as generation, distribution, management and most significantly application of renewable energy. This paper takes a broader look at both aspects in which ICTs are making our world eco-sustainable i.e., making other technologies smarter and incorporating renewable energy sources wherever possible.     

Innovative Citizen’s Services through Public Cloud in Pakistan: User’s Privacy Concerns and Impacts on Adoption

Mobile Networks and Applications - The world is going to be more and more digital with effective utilization of information and communication technologies in government services to provide services...     

Prediction of Drug-Drug Interactions Based on Multi-layer Feature Selection and Data Balance

Drug-drug interactions (DDIs) occur when two drugs react with each other, which may cause unex-pected side effects and even death of the patient. Methods that use adverse event reports to predict unexpected DDIs are limited by two critical yet challenging issues. One is the diffi culty of selecting discriminative features from numer-ous redundant and irrelevant adverse events for modeling. The other is the data imbalance, i.e., the drug pairs causing adverse effects are far less than those not causing adverse effects, which leads to poor accuracy of DDIs detection. We propose a multi-layer feature selection method to select discriminative adverse events and apply an over-sampling technique to make the data balanced. The experimental re-sults show that the validation accuracy of positive DDIs on the Canada Vigilance Adverse Reaction Online Database increases to two times, and 110 DDIs are identified on the drug interactions checker of Drugs.com in USA.     

Causes of low vision and blindness in south western Saudi Arabia. A hospital-based study

The authors studied 1,681 consecutive patients who attended their ophthalmic outpatient clinics over a period of 12 months to determine the patients' visual acuity status and the causes of any visual loss. Using the World Health Organization criteria for definition of visual acuity status, 1004 (59.7%) patients had normal vision. Four hundred and thirty-one (25.6%) patients had low vision or visual impairment and 246 (14.6%) patients were blind. Twenty-eight (1.9%) patients had no light perception in both eyes. Cataract, both in isolation and co-existing with other ocular pathology, was the major cause of both low vision and blindness (58.5% and 81.7%, respectively). A concerted attack on cataract alone will markedly reduce blindness and low vision in this region.     

微通道内液滴/气泡破裂动力学分析

微化学工程与技术是现代化学工程学科的前沿领域。微通道内液滴及气泡破裂动力学是决定多相过程并行微通道数目放大的基础与难点。破裂流型转换条件、界面动力学和尺寸调控等三方面是微通道内液滴与气泡破裂动力学的主要研究对象。讨论了对称微通道、非对称微通道、多级微通道、旁路微通道、含有障碍物的微通道内气泡和液滴破裂行为及影响因素,指出了目前微尺度下气泡与液滴破裂行为相关研究工作存在的不足,并对该领域未来的发展进行了展望。