In recent years, cloud computing paradigm has emerged as an internet-based technology to realize the utility model of computing for serving compute-intensive applications. In the cloud computing paradigm, the IT and business resources, such as servers, storage, network, and applications, can be dynamically provisioned to cloud workloads submitted by end-users. Since the cloud workloads submitted to cloud providers are heterogeneous in terms of quality attributes, management and analysis of cloud workloads to satisfy Quality of Service (QoS) requirements can play an important role in cloud resource management. Therefore, it is necessary for the provisioning of proper resources to cloud workloads using clustering of them according to QoS metrics. In this paper, we present a hybrid solution to handle the resource provisioning issue using workload analysis in a cloud environment. Our solution utilized the Imperialist Competition Algorithm (ICA) and K-means for clustering the workload submitted by end-users. Also, we use a decision tree algorithm to determine scaling decisions for efficient resource provisioning. The effectiveness of the proposed approach under two real workloads traces is evaluated. The simulation results demonstrate that the proposed solution reduces the total cost by up to 6.2%, and the response time by up to 6.4%, and increases the CPU utilization by up to 13.7%, and the elasticity by up to 30.8% compared with the other approaches.

Resource provisioning using workload clustering in cloud computing environment: a hybrid approach

Digital photoelasticity: Recent developments and diverse applications

In recent years, cloud computing has emerged as the most popular technologies for accessing and delivering enterprise applications as the services to the end users over the Internet. Since different enterprises may offer web services with various capabilities, these web services can be combined with other to provide the complete functionality of a large software application to meet the users’ requests. Therefore, the service composition as an NP-hard optimization problem to combine the distributed and heterogeneous web services is introduced as a challenging issue. In this work, we propose a linear programming approach to web service composition problem which is called ‘LP-WSC’ to select the most efficient service per request in a geographically distributed cloud environment for improving the quality-of-service criteria. Finally, we evaluate the effectiveness of our approach under three scenarios with varying the number of atomic services per set. The experimental results indicate that the proposed approach significantly reduces the cost of selection and composition of the services and also increases the availability of services and the reliability of the servers compared with the other approaches.

LP-WSC: a linear programming approach for web service composition in geographically distributed cloud environments

Computational analysis of Bayer colour filter arrays and demosaicking algorithms in digital photoelasticity

Applicability of colour transfer techniques in Twelve fringe photoelasticity (TFP)

An improved normalization technique for white light photoelasticity

Precursor gas flow rate variation (30–80 sccm) in the plasma‐enhanced chemical vapor deposition (PECVD) process of intrinsic a‐Si:H layer deposition using SiH4/H2 (equal ratio) plasma is explored and its effect on the i‐a‐Si:H/c‐Si interface passivation is investigated. A window of intermediate gas flow rates is determined for good quality surface passivation of n‐type c‐Si. Maximum effective minority carrier lifetime (τeff) above 1 ms, implied open‐circuit voltage (iVoc) ≈ 710 mV, and low interface defect density (Dit) ≈3.5 × 109 cm−2 eV−1 are obtained at an intermediate gas flow rate. The SiH4:H2 discharge emission characteristics, and the a‐Si:H film characteristics such as hydrogen concentration, film density, optical band gap, and refractive index, are also investigated. To examine the effect of the flow rate variation on the performance of the final device, front‐junction silicon heterojunction solar cells are fabricated on n‐type Si wafers, and ≈17% efficient cells are fabricated with an open‐circuit voltage (Voc) close to 690 mV at an optimized gas flow rate. This study provided information related to the transient plasma instability, SiH4 depletion, secondary reactions in the plasma, and flux of radicals toward the substrate for the film growth with a good level of surface passivation.

Effect of Gas Flow Rate in PECVD of Amorphous Silicon Thin Films for Interface Passivation of Silicon Heterojunction Solar Cells

The use of theoretical calibration table for fringe pattern demodulation in isochromatic images is revisited and a sensitivity analysis of material stress fringe value to generate theoretical calibration table is studied. The influence of filter parameter ‘R’ in normalization is discussed and its nuances are brought out. A substitution for theoretical calibration table and a new normalization technique is proposed to alter the dynamic range over the entire model domain of the isochromatic image suitably.

Development of a New Normalization Technique for Twelve Fringe Photoelasticity (TFP)

Nickel Oxide (NiOx) based hole-selective contact silicon heterojunction (SHJ) solar cells are fabricated with SiOx and i-a-Si:H surface passivation layers. The power conversion efficiency (η) of ∼17.3% and open-circuit voltage (Voc) of ∼670 mV is achieved from the cell with i-a-Si:H layer compared to η of ∼15.26% and Voc of ∼580 mV with SiOx layer. The significant improvement in Voc of the cell with i-a-Si:H layer is due to better passivation of the silicon surface dangling bonds than the wet chemically grown SiOx layer. Whereas, slightly better short-circuit (Jsc) of ∼1.5 mA/cm2 from the cell with SiOx layer is observed due to minimization of parasitic absorption in the NiOx layer, which is also confirmed by quantum efficiency analysis. The contact resistivity measurements with p-c-Si/NiOx and n-c-Si/NiOx structures are also carried out to verify the hole selectivity properties of the NiOx film. The simulation results with NiOx hole selective layer show a large window to optimize the ITO layer's electronic properties without compromising the device's performance compared to p-a-Si:H hole-selective SHJ cell. 

https://aip.scitation.org/doi/pdf/10.1063/5.0089230

Nickel oxide-based hole-selective contact silicon heterojunction solar cells

In the present study Li+ co-doped ZnMoO4:Eu3+ phosphor is prepared through Polyol method. The XRD has resulted triclinic structure of the ZnMoO4 sample. TEM and HRTEM illustrate rod-like morphology of the present samples. The PL-spectra has been recorded at 266, 395 and 465 nm excitation wavelength and characteristic emission peaks of the Eu3+ ion are observed. It is observed that the alkali lithium ion fills the vacancy which might be created due to mismatching between the oxidation states of metal and lanthanide ion. In this work highest PL-intensity observed for 10 at% Li+ co-doped sample. Moreover, color purity and quantum efficiency for 10 at% Li+ co-doped sample is found to 97 % and 35 %, respectively. Judd-Ofelt parameters have been calculated for all the samples and are correlated with the observed emission. The deep red emission from Li+ co-doped ZnMoO4:Eu3+ indicates that present phosphor has potential for white light emitting diodes and bio-imaging applications. 

Deep Red Emission through Europium and Lithium Co-doped Zinc Molybdate: Structural, Optical Analysis and Judd-Ofelt Intensity Parameters Calculation for Eu3+ ion

Ashutosh Pandey

Papers

An improved normalization technique for white light photoelasticity

Effect of Gas Flow Rate in PECVD of Amorphous Silicon Thin Films for Interface Passivation of Silicon Heterojunction Solar Cells

Development of a New Normalization Technique for Twelve Fringe Photoelasticity (TFP)

Nickel oxide-based hole-selective contact silicon heterojunction solar cells

Deep Red Emission through Europium and Lithium Co-doped Zinc Molybdate: Structural, Optical Analysis and Judd-Ofelt Intensity Parameters Calculation for Eu3+ ion