215 research outputs found
Cloud Computing: Current and Future Impact on Organizations
This project focuses on the business application of cloud computing, both at present and in the future. This investigation aims to assist business users of cloud computing services to improve the perception of cloud computing, to assess the value of their cloud computing service relationships, and to assist in selecting appropriate cloud computing services. This project bases its information on the existing cloud computing technology to clarify the technical aspects of current cloud services and companies. It presents the key elements of conception of cloud computing, its definitions, main service models, and implementation types. Ultimately, this paper analyzes the cons and pros of cloud computing based on business using cases. Also, this paper includes a demonstration to display the process of the cloud vendor providing service
Aerosol-Assisted Chemical Vapour Deposition (AACVD) of Silver Nanoparticle Decorated Tungsten Oxide Nanoneedle for Use in Oxygen Gas Sensing
Semiconducting metal oxides (SMOX) gas sensors, such as tungsten oxide (WO3), have been developed in depth for use in toxic gas detection, such as nitrogen oxides (NOx). With the addition of catalytic nanoparticles, like Ag, Pt, Pd and etc., the sensing properties, the three ‘S’ (sensitivity, selectivity and stability), can be significantly improved. This thesis details a two-step synthesis method for the fabrication of Ag nanoparticle decorated WO3 nanoneedle by using different silver metal precursors, including silver nitrate (AgNO3), silver 2-aminoethanol (Ag-EA), silver 1-aminopropan-2-ol (Ag-AP) and silver 2-methyl-2-aminopropan-1-ol (Ag-AMP), in a vapour deposition process. A series of experiments were conducted to investigate the parameters that affect the growth of the materials microstructure including deposition temperature, deposition time, flow rate of N2 carrier gas and concentration of precursor solution. Physical property characterization techniques including UV/Vis, XRD, XPS, SEM and TEM, have been systematically applied for all WO3 and Ag-decorated WO3 samples and sensor materials. Oxygen sensors’ have been considered as the critical component of Engine Management System for several decades. Gas sensing performance was carried out toward different O2 concentration between 1 and 20% at various operating temperatures. The sensing response revealed that the decoration of Ag nanoparticle on WO3 sensors significantly improved sensing properties as compared to undecorated WO3 sensors. An optimal gas response with silver-decorated WO3 is enhanced 400% compared to an undecorated WO3 sensor at an optimum operating temperature at 350 °C towards 20% oxygen at a relative humidity level ~ 85% by using AgNO3 as a precursor. An enhancement was also observed for the Ag decorated WO3 sensors fabricated using organometallic silver precursors, with a dramatically increasing in baseline resistance for these Ag@WO3 sensors. Sensing mechanisms, are proposed to explain the enhancement in sensing response
Algorithmically Effective Differentially Private Synthetic Data
We present a highly effective algorithmic approach for generating
-differentially private synthetic data in a bounded metric space
with near-optimal utility guarantees under the 1-Wasserstein distance. In
particular, for a dataset in the hypercube , our algorithm
generates synthetic dataset such that the expected 1-Wasserstein distance
between the empirical measure of and is for
, and is for . The
accuracy guarantee is optimal up to a constant factor for , and up to
a logarithmic factor for . Our algorithm has a fast running time of
for all and demonstrates improved accuracy
compared to the method in (Boedihardjo et al., 2022) for .Comment: 23 page
Differentially private low-dimensional representation of high-dimensional data
Differentially private synthetic data provide a powerful mechanism to enable
data analysis while protecting sensitive information about individuals.
However, when the data lie in a high-dimensional space, the accuracy of the
synthetic data suffers from the curse of dimensionality. In this paper, we
propose a differentially private algorithm to generate low-dimensional
synthetic data efficiently from a high-dimensional dataset with a utility
guarantee with respect to the Wasserstein distance. A key step of our algorithm
is a private principal component analysis (PCA) procedure with a near-optimal
accuracy bound that circumvents the curse of dimensionality. Different from the
standard perturbation analysis using the Davis-Kahan theorem, our analysis of
private PCA works without assuming the spectral gap for the sample covariance
matrix.Comment: 21 page
Analysis of heat transfer and thermal environment in a rural residential building for addressing energy poverty
Reducing energy consumption and creating a comfortable thermal indoor environment in rural residential buildings can play a key role in fighting global warming in China. As a result of economic development, rural residents are building new houses and modernizing existing buildings. This paper investigated and analyzed a typical rural residential building in the Ningxia Hui Autonomous Region in Northwest China through field measurements and numerical simulation. The results showed that making full use of solar energy resources is an important way to improve the indoor temperature. Reasonable building layout and good thermal performance of the building envelope can reduce wind velocities and convective heat loss. Insulation materials and double-glazed windows should be used to reduce energy loss in new buildings, although it is an evolution process in creating thermally efficient buildings in rural China. This research provides a reference for the design and construction of rural residential buildings in Northwest China and similar areas for addressing energy poverty
NON-INTERFERING SEQUENCE FOR MASSIVE DATA TRAFFIC IN LOW-POWER LOSSY NETWORKS
Techniques are described herein for generating a non-interfering sequence. This mechanism mainly comprises two steps. The first step involves computing and generating a schedule, and the second step involves receiving metering data from all nodes. After the second step ends, the head end system builds a residual node set containing all nodes that failed to report data in a given schedule, and then the first and second steps are repeated until the residual set is empty. The two steps are performed serially. The techniques described herein optimize these two steps. In particular, first a system mathematical mode is built from a Routing Protocol for Low-Power and Lossy Networks (RPL) p-table and link neighbor, second the constraint condition is constructed, and third the parameter is adjusted and the schedule is implemented
Deposition of tungsten oxide and silver decorated tungsten oxide for use in oxygen gas sensing
Tungsten oxide and silver-decorated tungsten oxide were investigated for the detection of oxygen in a humid environment. The sensor materials were deposited onto alumina sensor substrates via aerosol-assisted chemical vapour deposition. Results indicated that our sensors showed good sensitivity to oxygen, following an almost a linear relationship over a 0 to 20% concentration range. In comparison to WO3, the Ag-decorated sensors showed a much higher sensitivity and better response (sensitivity of 0.22 per %O2 vs 0.80 per %O2 for Ag decorated), making Ag-WO3 based sensors an interseting alternative to existing Pb-based sensors for quantitative oxygen sensing
Experimental study on sinomenine derivative modulating chemokine receptor in multiple myeloma cells
Background and purpose: The interaction of CXC motif chemokine receptor (CXCR) on the cell surface of multiple myeloma (MM) with chemokines in the bone marrow microenvironment is involved in proliferation, survival and extramedullary invasion of MM cells. Sinomenine derivative YL064 exerts its biological effects by targeting intracellular signaling regulators in MM cells. This study aimed to explore possible modulating and biological effects of sinomenine derivative YL064 on CXCR3 in MM cells. Methods: The MM cell lines H929 and MM1.S were used as in vitro models. H929-OE and MM1.S-OE cells with stable overexpression of CXCR3 were constructed with lentivirus vector. The effects of CXCR3 on clonal formation and migration of MM cells were detected by clone spot formation and transwell migration assay. Meanwhile, flow cytometry was used to analyze apoptotic rates of H929, H929-OE, MM1.S and MM1.S-OE cells treated with different concentrations of YL064. Furthermore, real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR) and Western blot assay were applied to detect expression levels of CXCR3 and its downstream signal regulators extracellular regulated protein kinase (ERK) and p-protein kinase B (p-AKT) in H929 and MM1.S cells before and after the treatment with YL064. Results: The clonal formation rates of H929-OE and MM1.S-OE cells with CXCR3 overexpression reached to 81.33%±5.79% and 73.00%±4.90%, which were significantly higher compared with H929 (58.33%±3.30%) and MM1.S cells (41.00%±3.14%). The migration proportion of H929-OE and MM1.S-OE cells were 7.90%±0.81% and 23.00%±1.63%, which were significantly higher compared with H929 (4.63%±0.37%) and MM1.S cells (14.63%±1.04%). After treatment with YL064, the apoptotic rates of H929-OE and MM1.S-OE cells were 29.80%±0.30% and 14.20%±0.26%, which were lower than those of H929 (33.40%±0.25%) and MM1.S cells (21.60%±0.21%). It was also shown that YL064 could reduce clonal formation and migration, inhibit CXCR3 gene transcription and downregulate expressions of CXCR3, ERK and AKT in H929 and MM1.S cells. Conclusions: CXCR3 might promote proliferation and invasion of MM cells. Sinomenine derivative YL064 could downregulate expressions of CXCR3 and its downstream signal regulators in MM cells, reduce abilities of clonal formation and migration, and induce apoptosis
PDGFRα reporter activity identifies periosteal progenitor cells critical for bone formation and fracture repair
The outer coverings of the skeleton, which is also known as the periosteum, are arranged in concentric layers and act as a reservoir for tissue-specific bone progenitors. The cellular heterogeneity within this tissue depot is being increasingly recognized. Here, inducible PDGFR alpha reporter animals were found to mark a population of cells within the periosteum that act as a stem cell reservoir for periosteal appositional bone formation and fracture repair. During these processes, PDGFR alpha reporter(+) progenitors give rise to Nestin(+) periosteal cells before becoming osteoblasts and osteocytes. The diphtheria toxin-mediated ablation of PDGFR alpha reporter(+) cells led to deficits in cortical bone formation during homeostasis and a diminutive hard callus during fracture repair. After ossicle transplantation, both mouse PDGFR alpha reporter(+) periosteal cells and human Pdgfr alpha(+) periosteal progenitors expand, ossify, and recruit marrow to a greater extent than their counterpart periosteal cells, whereas PDGFR alpha reporter(-) periosteal cells exhibit a predisposition to chondrogenesis in vitro. Total RNA sequencing identified enrichment of the secreted factors Fermt3 and Ptpn6 within PDGFR alpha reporter(+) periosteal cells, which partly underlie the osteoblastogenic features of this cell population
Comparative transcriptomic analyses of two sugarcane Saccharum L. cultivars differing in drought tolerance
Sugarcane (Saccharum spp.) is an important cash crop, and drought is an important factors limiting its yield. To study the drought resistance mechanism of sugarcane, the transcriptomes of two sugarcane varieties with different levels of drought resistance were compared under different water shortage levels. The results showed that the transcriptomes of the two varieties were significantly different. The differentially expressed genes were enriched in starch and sucrose metabolism, linoleic acid metabolism, glycolysis/gluconeogenesis, and glyoxylate and dicarboxylate metabolic pathways. Unique trend genes of the variety with strong drought resistance (F172) were significantly enriched in photosynthesis, mitogen-activated protein kinases signaling pathway, biosynthesis of various plant secondary metabolites, and cyanoamino acid metabolism pathways. Weighted correlation network analysis indicated that the blue4 and plum1 modules correlated with drought conditions, whereas the tan and salmon4 modules correlated with variety. The unique trend genes expressed in F172 and mapped to the blue4 module were enriched in photosynthesis, purine metabolism, starch and sucrose metabolism, beta-alanine metabolism, photosynthesis-antenna proteins, and plant hormone signal transduction pathways. The expression of genes involved in the photosynthesis-antenna protein and photosynthesis pathways decreased in response to water deficit, indicating that reducing photosynthesis might be a means for sugarcane to respond to drought stress. The results of this study provide insights into drought resistance mechanisms in plants, and the related genes and metabolic pathways identified may be helpful for sugarcane breeding in the future
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