5,794 research outputs found
A Class of MSR Codes for Clustered Distributed Storage
Clustered distributed storage models real data centers where intra- and
cross-cluster repair bandwidths are different. In this paper, exact-repair
minimum-storage-regenerating (MSR) codes achieving capacity of clustered
distributed storage are designed. Focus is given on two cases: and
, where is the ratio of the available cross- and
intra-cluster repair bandwidths, is the total number of distributed nodes
and is the number of contact nodes in data retrieval. The former represents
the scenario where cross-cluster communication is not allowed, while the latter
corresponds to the case of minimum cross-cluster bandwidth that is possible
under the minimum storage overhead constraint. For the case, two
types of locally repairable codes are proven to achieve the MSR point. As for
, an explicit MSR coding scheme is suggested for the
two-cluster situation under the specific condition of .Comment: 9 pages, a part of this paper is submitted to IEEE ISIT201
VIABILITY, FATTY ACID COMPOSITION, AND STRUCTURE OF THE CORALLINE ALGA CORALLINA PILULIFERA
The decrease in the seaweed flora in some rocky areas, known as algal whitening or barren ground, is associated with some species of coralline algae. To determine the biological characteristics of a representative species of branched coralline alga, the number of medullary tiers was counted and ranged from 12 to 16. The 18S rDNA, psbA, and rbcL genes were used to confirm the identification of Corallina pilulifera. Measuring viability using triphenyl tetrazolium chloride showed highly viability from December to January. Cultural conditions of 16 C, 16 h light:8 h dark cycle, and 40 mu E m(-2) s(-1) light intensity were optimal for maintaining the viability of the coralline alga for up to three days. The fatty acids included 31.4% omega-3 eicosapentaenoic acid. Scanning electron microscopy of the surface structure revealed unique round wells about 7.9 +/- 1.3 mu m in diameter. The coralline alga, preventing fleshy seaweeds, may be used as a potential template for the creation of new environmentally friendly biomimetic antifouling material against the attachment of soft foulants, especially micro- and macroalgae.X111Ysciescopu
Association Between Proton Pump Inhibitor Use During Early Pregnancy and Risk of Congenital Malformations
Importance: Proton pump inhibitors (PPIs) are increasingly used during pregnancy; however, several observational studies have raised concerns about an increased risk of specific types of congenital malformations. Objective: To examine the association between PPI exposure during early pregnancy and the risk of congenital malformations. Design, Setting, and Participants: This population-based cohort study used data from the National Health Insurance Service-National Health Information Database of South Korea (2010-2020); sibling-controlled analyses were conducted to account for familial factors. A total of 2 696 216 pregnancies in women aged 19 to 44 years between June 1, 2011, and December 31, 2019, and their live-born infants were identified. Pregnant women who were exposed to known teratogens or who delivered infants with chromosomal abnormalities or genetic syndromes were excluded. Data on participant race and ethnicity were not collected because the National Health Information Database does not report this information. Exposures: Proton pump inhibitor use during the first trimester. Main Outcomes and Measures: Primary outcomes were major congenital malformations, congenital heart defects, cleft palate, hydrocephalus, and hypospadias. The subtypes of major congenital malformations and congenital heart defects were evaluated as exploratory outcomes. Propensity score fine stratification was used to control for potential confounders, and a weighted generalized linear model was used to estimate relative risks with 95% CIs. Results: Of 2 696 216 pregnancies (mean [SD] maternal age, 32.1 [4.2] years), 40 540 (1.5%; mean [SD] age, 32.4 [4.6] years) were exposed to PPIs during the first trimester. The absolute risk of major congenital malformations was 396.7 per 10 000 infants in PPI-exposed pregnancies and 323.4 per 10 000 infants in unexposed pregnancies. The propensity score-adjusted relative risks were 1.07 (95% CI, 1.02-1.13) for major congenital malformations, 1.09 (95% CI, 1.01-1.17) for congenital heart defects, 1.02 (95% CI, 0.72-1.43) for cleft palate, 0.94 (95% CI, 0.54-1.63) for hydrocephalus, and 0.77 (95% CI, 0.51-1.17) for hypospadias. In the sibling-controlled analyses, no associations were observed between PPI use and primary outcomes, including major congenital malformations (odds ratio, 1.05; 95% CI, 0.91-1.22) and congenital heart defects (odds ratio, 1.07; 95% CI, 0.88-1.30). A range of sensitivity analyses revealed results that were similar to the main findings. Conclusions and Relevance: In this cohort study, the use of PPIs during early pregnancy was not associated with a substantial increase in the risk of congenital malformations, although small increased risks were observed for major congenital malformations and congenital heart defects; findings from sibling-controlled analyses revealed that PPIs were unlikely to be major teratogens. These findings may help guide clinicians and patients in decision-making about PPI use in the first trimester
Popularity-Based Adaptive Content Delivery Scheme with In-Network Caching
To solve the increasing popularity of video streaming services over the Internet, recent research activities have addressed the locality of content delivery from a network edge by introducing a storage module into a router. To employ in-network caching and persistent request routing, this paper introduces a hybrid content delivery network (CDN) system combining novel content routers in an underlay together with a traditional CDN server in an overlay. This system first selects the most suitable delivery scheme (that is, multicast or broadcast) for the content in question and then allocates an appropriate number of channels based on a consideration of the content’s popularity. The proposed scheme aims to minimize traffic volume and achieve optimal delivery cost, since the most popular content is delivered through broadcast channels and the least popular through multicast channels. The performance of the adaptive scheme is clearly evaluated and compared against both the multicast and broadcast schemes in terms of the optimal in-network caching size and number of unicast channels in a content router to observe the significant impact of our proposed scheme
Environmental and economic assessment of hybrid FO-RO/NF system with selected inorganic draw solutes for the treatment of mine impaired water
© 2017 Elsevier B.V. A hybrid forward osmosis (FO) and reverse osmosis (RO)/nanofiltration (NF) system in a closed-loop operation with selected draw solutes was evaluated to treat coal mine impaired water. This study provides an insight of selecting the most suitable draw solution (DS) by conducting environmental and economic life cycle assessment (LCA). Baseline environmental LCA showed that the dominant components to energy use and global warming are the DS recovery processes (i.e. RO or NF processes) and FO membrane materials, respectively. When considering the DS replenishment in FO, the contribution of chemical use to the overall global warming impact was significant for all hybrid systems. Furthermore, from an environmental perspective, the FO-NF hybrid system with Na2SO4 shows the lowest energy consumption and global warming with additional considerations of final product water quality and FO brine disposal. From an economic perspective, the FO-NF with Na2SO4 showed the lowest total operating cost due to its lower DS loss and relatively low solute cost. In a closed-loop system, FO-NF with NaCl and Na2SO4 had the lowest total water cost at optimum NF recovery rates of 90 and 95%, respectively. FO-NF with Na2SO4 had the lowest environmental and economic impacts. Overall, draw solute performances and cost in FO and recovery rate in RO/NF play a crucial role in determining the total water cost and environmental impact of FO hybrid systems in a closed-loop operation
Plasma-Enhanced ALD of TiO2 Thin Films on SUS 304 Stainless Steel for Photocatalytic Application
Plasma-enhanced atomic layer deposition (PE-ALD) of TiO2 thin films using Ti(NMe2)(4) [tetrakis(dimethylamido) Ti] and O-2 plasma were prepared on stainless steel to show the self-cleaning effect. The TiO2 thin films deposited on stainless steel have high growth rate, large surface roughness, and low impurities. The film deposited below 200 degrees C was amorphous, while the films deposited at 300 and 400 degrees C showed anatase and rutile phases, respectively. The contact angle measurements on crystalline PE-ALD TiO2 thin films exhibited superhydrophilicity after UV irradiation. The TiO2 thin film with anatase phase deposited at 300 degrees C showed the highest photocatalytic efficiency, which is higher than on Activ glass or thermal ALD TiO2 films. We suggest that anatase structure and large surface area of TiO2 thin film on stainless steel are the main factors for the high photocatalytic efficiency. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3095515] All rights reserved.X117sciescopu
Techno-economic assessment of fertiliser drawn forward osmosis process for greenwall plants from urban wastewater
© 2019 Institution of Chemical Engineers Pressure-assisted osmosis (PAO) has been suggested to integrate with fertiliser driven forward osmosis (FDFO) to improve the overall efficiency of simultaneous wastewater reuse and fertiliser osmotic dilution. This study aims to demonstrate the techno-economic feasibility of pressure-assisted fertiliser driven forward osmosis (PAFDO) hybrid system compared to the existing ultraviolet and reverse osmosis (UV–RO) process. The results showed that coupling FDFO with PAO (i.e. PAFDO) could help fulfill the water quality required for greenwall fertigation. An economic analysis on capital and operational costs for the PAFDO showed that the PAO mode application at a lower FDFO dilution stage could significantly reduce the costs. However, when considering the different applied pressures in PAO (i.e. 2, 4, and 6 bar), the increase in the total water cost was not significant. This indicates that the dilution stage for applying PAO is more sensitive to the total water cost of the PAFDO than the applied pressure. A coupling of higher average water flux (>10 L/m2h) and lower draw solution (DS) dilution factor (DF < 60) is recommended. Therefore, this could make the PAFDO system economically viable compared to the benchmark for the UV-RO disinfection system
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