Process Tolerant and Power Efficient SRAM Cell for Internet of Things Applications

The use of Internet of Things(IoT)applications become dominant in many systems.Its on-chip data processing and computations are also increasing consistently.The battery enabled and low leakage memory system at subthreshold regime is a critical requirement for these IoT applications.The cache memory designed on Static Random-Access Memory(SRAM)cell with features such as low power,high speed,and process tolerance are highly important for the IoT memory system.Therefore,a process tolerant SRAM cell with low power,improved delay and better stability is presented in this research paper.The proposed cell comprises 11 transistors designed with symmetric approach for write operations and single ended circuit for read operations that exhibits an average dynamic power saving of 43.55%and 47.75%for write and 35.59%and 36.56%for read operations compared to 6 T and 8 T SRAM cells.The cell shows an improved write delay of 26.46%and 37.16%over 6 T and 8T and read delay is lowered by 50.64%and 72.90%against 6 T and 10 T cells.The symmetric design used in core latch to improve the write noise margin(WNM)by 17.78%and 6.67%whereas the single ended separate read circuit improves the Read Static Noise Margin(RSNM)by 1.88x and 0.33x compared to 6 T and 8T cells.The read power delay product and write power delay product are lower by 1.94x,1.39x and 0.17x,2.02x than 6 T and 8 T cells respectively.The lower variability from 5000 samples validates the robustness of the proposed cell.The simulations are carried out in Cadence virtuoso simulator tool with Generic Process Design Kit(GPDK)45 nm technology file in this work.

Design,characterization and fabrication of an In_(0.53)Ga_(0.47)As planar Gunn diode operating at millimeter waves

This paper describes the design,characterization and fabrication of a planar In0.53Ga0.47As based planar Gunn diode on an In P semi-insulating substrate.The planar Gunn diode was designed in Coplanar Waveguide(CPW)format with an active channel length and width of 4μm and 120μm respectively,and modeled using the Advanced Design System(ADS-2009)simulation package.The initial experimental measurements have given a fundamental oscillation frequency of 63.5 GHz with a RF output power of-6.6 d Bm,which is the highest recorded power for an In P based planar Gunn diode.

Tensile bond anchorage properties of Australian 500N steel bars in concrete

In order to investigate the tensile bond anchorage properties of Australian 500N steel bars in concrete, 111 pullout tests were conducted. The precise bond slip values have been gained by using the laser displacement sensor with high resolution, including the complete bond-slip curves. How the main anchorage factors such as concrete strength, bar diameter （8, I0, 12, 16, 20, 24, 28, 32 and 36 mm） the concrete covered, embedded length and transverse reinforcement influencing the bond anchorage properties was studied under tensile condition. The process of the tensile force-slip failure for Australian 500N reinforcing steel can be divided into five stages： elastic stage, local slip stage, slip in ascent stage, slip in descent stage and remnant stage. The formula for calculating the tensile bond strength of Australian 500N reinforcing bar in concrete was proposed according to the test results, including the consistent model for tensile bond-slip relationship.

Securing Cloud Computing from Flash Crowd Attack Using Ensemble Intrusion Detection System

Flash Crowd attacks are a form of Distributed Denial of Service(DDoS)attack that is becoming increasingly difficult to detect due to its ability to imitate normal user behavior in Cloud Computing(CC).Botnets are often used by attackers to perform a wide range of DDoS attacks.With advancements in technology,bots are now able to simulate DDoS attacks as flash crowd events,making them difficult to detect.When it comes to application layer DDoS attacks,the Flash Crowd attack that occurs during a Flash Event is viewed as the most intricate issue.This is mainly because it can imitate typical user behavior,leading to a substantial influx of requests that can overwhelm the server by consuming either its network bandwidth or resources.Therefore,identifying these types of attacks on web servers has become crucial,particularly in the CC.In this article,an efficient intrusion detection method is proposed based on White Shark Optimizer and ensemble classifier(Convolutional Neural Network(CNN)and LighGBM).Experiments were conducted using a CICIDS 2017 dataset to evaluate the performance of the proposed method in real-life situations.The proposed IDS achieved superior results,with 95.84%accuracy,96.15%precision,95.54%recall,and 95.84%F1 measure.Flash crowd attacks are challenging to detect,but the proposed IDS has proven its effectiveness in identifying such attacks in CC and holds potential for future improvement.

An Experience of On-site PD Testing for Condition Monitoring of an 11 kV PILC Cable Insulation System

A cable circuit of a substation in the United Kingdom showed high level of PD activities during a survey using hand hold PD testing equipment. The authors were invited to carry out on-site PD testing experiment to further diagnose and locate the potential problem of the cable system. This paper presents the experience of the present authors carrying out the cable test. Following a brief introduction to the experiment equipments and physical connections, the paper analyses the data collected from the testing, including PD pulse shape analysis, frequency spectrum analysis and phase resolved PD pattern analysis. Associated with PD propagation direction identification, PD source diagnosis and localisation was made. Four different types of sensors, which were adapted during the testing, are shown to have different frequency bandwidths and performed differently. Aider comparing the parameters of the sensor and the PD signals detected by individual sensor, optimal PD monitoring bandwidth for cable system is suggested.

IoT:Understanding from a Management Perspective for the Railway Sector

The railway industry is a key part of any country’s transportation infrastructure.The railway industry supports the competitive advantage of the country’s economy,providing a vital link in the supply chain of most manufacturing,agriculture,and other allied industries.However,in many countries,the railway needs an upgrade,concerning maintenance.In most countries their railways still run on old architecture and are in vital need of improvement into the 21st century technological marvels.To meet the myriad of the industry’s problems,it is proposed in this paper that it is ripe to introduce IoT(Internet of Things)for the competitive advantage of the industry.A qualitative analysis of the issues was conducted through a thematic approach.The results obtained have shown that there is a gap within the industry’s knowhow and modern forms of management perspectives using assisted smart technological.From the findings of the analysis,it is proposed that a rethink of how issues of moving forward should include aspects of smart technology that include IoT and smart systems using some form of AI(artificial intelligence)approach.The proposed approach in this paper will help modernise the railway sector and finally set it on a better roadmap for future improvement to the entire rail network and its trains.

钢筋受压黏结滑移模型

为研究钢筋的受压黏结滑移关系,采用分辨率较高的激光位移计,对一批短锚长试件进行系列推出试验研究,得到精确度较高的黏结滑移值及完整的试验黏结滑移关系曲线,描述钢筋在混凝土中的受压黏结滑移破坏全过程:弹性阶段、局部滑移阶段、滑移上升段、滑移下降段和残余段。在对试验得到的较短锚长试件推出试验结果分析的基础上,经统计回归和分析,提出钢筋的受压黏结滑移曲线模型,并与试验结果进行对比。

中欧美拉伸锚固长度比较研究

对中欧美规范中拉伸锚固长度的定义和计算公式进行了比较,并选取不同工况,重点考虑了钢筋间距和直径、混凝土强度和保护层厚度的影响,用规范公式对梁和板中的锚固长度进行了计算分析。通过对比发现,在几种主要因素影响下,Eurocode 2锚固长度曲线变化趋势和极限锚固长度曲线变化趋势整体上比较接近。当考虑钢筋间距和直径的影响时,在梁中和板中,GB 50010—2002的变化趋势和Eurocode 2比较相似,值也比较接近。在考虑混凝土强度和保护层厚度时,GB 50010—2002精细方法计算值在影响因素取值较大时,对于板来说偏保守,建议取个适当的折减系数。ACI318-05多数因素影响下均偏保守,建议考虑相应因素的影响时取合适的折减系数。

澳洲500N钢筋与混凝土受拉黏结滑移模型研究

为了研究澳洲500N钢筋与混凝土的受拉黏结滑移关系,采用分辨率较高的激光位移传感器,对一批短锚长试件进行了系列拔出试验研究,得到精确度较高的黏结滑移值及完整的试验黏结滑移关系曲线,详细描述了澳洲500N钢筋在混凝土中的受拉黏结滑移破坏全过程:弹性阶段、局部滑移阶段、滑移上升段、滑移下降段和残余段.在对试验得到的较短锚长构件拔出试验结果分析的基础之上,经统计回归和分析,提出了澳洲500N钢筋与混凝土的受拉黏结滑移连续型曲线模型,并和试验结果做了对比.

固体氧化物燃料电池电解质材料的研究进展

固体氧化物燃料电池(SOFC)是一种能量转换效率高、环境友好和燃料灵活的全固态发电设备,为能源资源的可持续发展提供选择。氧离子在固体电解质中是通过氧空位传导的,即增大氧空位浓度是提高离子电导率的关键,而高离子电导率的电解质材料促进了SOFC发展。综述了固体电解质的离子传输机制和ZrO_(2)基电解质、CeO_(2)基电解质、Bi_(2)O_(3)基电解质和LaGaO_(3)基电解质材料的结构、研究进展以及优缺点,并对未来电解质材料的研究发展趋势进行了展望。

固体氧化物燃料电池阴极材料的研究进展

阴极材料是固体氧化物燃料电池的重要组成。提高阴极材料的电子/离子电导率、降低极化电阻是使SOFC低温化运行、延长电池使用寿命的重要方法。阴极材料的高电子电导性促使钙钛矿结构氧化物在阴极材料的研究领域占据主导地位。综述了钙钛矿结构阴极、尖晶石结构阴极和Ruddlesden-popper型结构阴极材料的研究进展,并展望了未来阴极材料的发展方向。

Geometric Mean Decomposition Based Hybrid Precoding for Millimeter-Wave Massive MIMO

Hybrid precoding can reduce the number of required radio frequency(RF)chains in millimeter-Wave(mmWave) massive MIMO systems. However, existing hybrid precoding based on singular value decomposition(SVD) requires the complicated bit allocation to match the different signal-to-noise-ratios(SNRs) of different sub-channels. In this paper,we propose a geometric mean decomposition(GMD)-based hybrid precoding to avoid the complicated bit allocation. Specifically,we seek a pair of analog and digital precoders sufficiently close to the unconstrained fully digital GMD precoder. To achieve this, we fix the analog precoder to design the digital precoder, and vice versa. The analog precoder is designed based on the orthogonal matching pursuit(OMP) algorithm, while GMD is used to obtain the digital precoder. Simulations show that the proposed GMD-based hybrid precoding achieves better performance than the conventional SVD-based hybrid precoding with only a slight increase in complexity.

Solving Travelling Salesman Problem with an Improved Hybrid Genetic Algorithm

We present an improved hybrid genetic algorithm to solve the two-dimensional Eucli-dean traveling salesman problem (TSP), in which the crossover operator is enhanced with a local search. The proposed algorithm is expected to obtain higher quality solutions within a reasonable computational time for TSP by perfectly integrating GA and the local search. The elitist choice strategy, the local search crossover operator and the double-bridge random mutation are highlighted, to enhance the convergence and the possibility of escaping from the local optima. The experimental results illustrate that the novel hybrid genetic algorithm outperforms other genetic algorithms by providing higher accuracy and satisfactory efficiency in real optimization processing.

Characteristics of the breakup and fragmentation of an electrohydrodynamic melt jet

In this study, the breakup of a melt jet into a viscous medium is investigated in the presence of an intense electric field. Fragmentation of the melt jet occurs due to both hydrodynamic and electrohydrodynamic （EHD） forces within two kinds of silicone oil of different viscosities. The size and shape characteristics of the produced particles have been studied using SEM images, and the particle size distributions were found to exhibit considerable variations when a voltage was applied and when both the viscosity and temperature of the base fluid were changed. The morphologies of the particles were also affected by the same parameters. For instance, by applying EHD force, significant enhancements in size reduction and increased roundness of the particles occurred. The breakup process of the melt jet was found to be dominant by hydrodynamic or electrohydrodynamic instabilities, depending on the situation. Governing mechanisms （instability） in the cases of pure hydrodynamic and electrohydrodynamic fragmentations are discussed.

A Hierarchical Game Model for Computation Sharing in Smart Buildings

Recently,initiatives to integrate Internet of Things(IoT)technologies into smart buildings have attracted extensive attention for improving the performance of buildings and the comfort of occupants.However,the amount of data generated by IoT devices remains a challenge to the building management systems(BMSs)in terms of intensity and complexity.Different from cloud computing and edge computing,we propose a computation sharing architecture in smart buildings to incentivize idle computing devices(ICDs,sellers)to offload computational tasks for the BMS(buyer).In this paper,we design a hierarchical game model,consisting of a Stackelberg game and a Cournot game,to achieve a dynamic increase in computational capacity for the BMS.To guarantee the utility of BMS and ICDs,the Stackelberg game model is built to analyze the interactions between BMS and ICDs.Then,the Cournot game model is presented to formulate the internal competition among multiple ICDs.Under the premise of the subgame perfect Nash equilibrium,the BMS can quote the optimal pricing strategy,and the ICDs can share the corresponding optimal amount of computing resources.Finally,the simulation results show that the BMS’s computational capacity is enhanced on-demand,and each participant in the game obtains maximal utility.

Mathematical Development and Verification of a Finite Volume Model for Morphodynamic Flow Applications

The accuracy and efficiency of a class of finite volume methods are investigated for numerical solution of morphodynamic problems in one space dimension.The governing equations consist of two components,namely a hydraulic part described by the shallow water equations and a sediment part described by the Exner equation.Based on different formulations of the morphodynamic equations,we propose a family of three finite volume methods.The numerical fluxes are reconstructed using a modified Roe’s scheme that incorporates,in its reconstruction,the sign of the Jacobian matrix in the morphodynamic system.A well-balanced discretization is used for the treatment of the source terms.The method is wellbalanced,non-oscillatory and suitable for both slow and rapid interactions between hydraulic flow and sediment transport.The obtained results for several morphodynamic problems are considered to be representative,and might be helpful for a fair rating of finite volume solution schemes,particularly in long time computations.

CFD investigation of dense phase pneumatic conveying at a pipeline enlargement

The practice of stepping a conveying line is not new and there are many examples in industry; however, the details of the flow behaviour at the step have not been extensively studied. Three step geometries were modelled： an ＇abrupt＇ step and two ＇gradual＇ step-up geometries from a pipe bore of 75-100 ram. The flow behaviour of a single plug of material passing through these geometries was investigated using the ＇Eulerian＇ CFD model from Fluent. Solids volume fractions were recorded at 0.01 s time steps at several point locations, and visualised throughout the pipe.

Quality measures of reconstruction filters for stereoscopic volume rendering

In direct volume rendering(DVR), the choice of reconstruction filter can have a significant effect on the visual appearance of the images produced and thus, on the perceived quality of a DVR rendered scene. This paper presents the results of a subjective experiment where participants stereoscopically viewed DVR rendered scenes and rated their subjective quality.The statistical analysis of the results focuses on the relationship between the quality of the stereoscopic scene and properties of the filters such as post-aliasing and smoothing, as well as the relationship between the quality of the stereoscopic scene and properties of the rendered images such as shape compactness.The experiment evaluated five reconstruction filters on four different volumetric datasets. Participants rated the stereoscopic scenes on four quality measures:depth quality, depth layout, lack of jaggyness, and sharpness. The results show that the correlation between the quality measures and post-aliasing and smoothing, which are properties associated with each reconstruction filter, is moderate and statistically insignificant. On the other hand, the correlation between the quality measures and compactness, which is a property specific to each rendered image, is strong and statistically significant.

Domain Decomposition Preconditioners for Discontinuous Galerkin Discretizations of Compressible Fluid Flows

In this article we consider the application of Schwarz-type domain decomposition preconditioners to the discontinuous Galerkin finite element approximation of the compressible Navier-Stokes equations.To discretize this system of conservation laws,we exploit the(adjoint consistent)symmetric version of the interior penalty discontinuous Galerkin finite element method.To define the necessary coarse-level solver required for the definition of the proposed preconditioner,we exploit ideas from composite finite element methods,which allow for the definition of finite element schemes on general meshes consisting of polygonal(agglomerated)elements.The practical performance of the proposed preconditioner is demonstrated for a series of viscous test cases in both two-and three-dimensions.

Structure creation in earthen construction materials:information from dry soil mixtures

There is increasing interest in the use of earthen construction materials,such as rammed earth,due to their inherent sustainability.These materials have been used by man for thousands of years and some of the earliest examples can be found in China.Features of the structures of these materials arise from the means of production.In particular,in situ earthen construction materials exhibit strong anisotropy due to their layered nature.A more subtle structure effect arises from the way that the earth mixture is deposited.This paper reviews and discusses stratification effects in dry soil mixtures,including some original experimental work,and indicates some links between the features of the dry mixtures and earthen construction materials.Improved understanding of the physical processes in play will allow more accurate specification of these materials in the future,and hence spread their use.