An Extendible Hashing Based Recovery Method in a Shared-Nothing Spatial Database Cluster

2006 ◽  
pp. 1126-1135
Author(s):  
Yong-Il Jang ◽  
Ho-Seok Kim ◽  
Soon-Young Park ◽  
Jae-Dong Lee ◽  
Hae-Young Bae
Keyword(s):  
Spatial Database ◽  
Recovery Method ◽  
Database Cluster ◽  
Extendible Hashing

ROCK OIL RESERVOIR STRUCTURE INFLUENCE ON THE FLAME STABILITY OF THE IN-SITU COMBUSTION RECOVERY METHOD

2019 ◽  
Author(s):  
Lucas Henrique Pagoto Deoclecio ◽  
Filipe Arthur Firmino Monhol ◽  
Antônio Carlos Barbosa Zancanella
Keyword(s):  
Flame Stability ◽  
Oil Reservoir ◽  
In Situ Combustion ◽  
Recovery Method

GUIDELINES FOR ACCESSING AND UTILIZING THE SFRES SPATIAL DATABASE

2017 ◽  
Author(s):  
Matthew Thomas Custer
Keyword(s):  
Spatial Database

Spatial Database Structure Design of Regional Geology Annals of China

2012 ◽  
Vol 13 (6) ◽  
pp. 720-726 ◽  
Author(s):  
Benxian FAN ◽  
Qinghe ZHANG ◽  
Yuanjing JU ◽  
Kunying HAN ◽  
Lan JIANG ◽  
...  
Keyword(s):  
Spatial Database ◽  
Structure Design ◽  
Regional Geology ◽  
Database Structure

Causes of gear pump fails and methods for their elimination

2020 ◽  
pp. 98-107
Author(s):  
Vitaliy A. Zuyevskiy ◽  
Daniil O. Klimyuk ◽  
Ivan A. Shemberev
Keyword(s):  
Adhesion Strength ◽  
Production Systems ◽  
Low Cost ◽  
High Strength ◽  
Strength Properties ◽  
Research Purpose ◽  
Working Fluid ◽  
Gear Pump ◽  
Repair Service ◽  
Recovery Method

Gear pumps are an important element of many production systems and their replacement in case of failure can be quite expensive, so it is important to have a modern and well-tuned technology for their recovery. There are many methods for restoring the pump's performance, depending on the reason that led to its failure. (Research purpose) The research purpose is in determining what causes most often lead to loss of pump performance, and developing a recovery method that provides the greatest post-repair service life of the pump and low cost of repair. (Materials and methods) Authors took into account that the applied coatings must have sufficient adhesion strength and resistance to mechanical, thermal and corrosion loads during operation. It was found that most often significant leaks of the working fluid, leading to failure, occur due to an increase in the gap between the inner surface of the housing and the gears due to active wear of the housing wells. Authors determined that the method of electric spark treatment of worn-out housing wells is best suited to perform the task (a large post-repair resource and low costs). (Results and discussion) It was found by laboratory studies of the adhesion strength of electric spark coatings with various electrodes that the best transfer of the material to the substrate is provided by bronze electrodes BrMKts3-1. It was noted that the coatings applied using the BrMKts3-1 electrode have high strength properties. (Conclusions) Research conducted in the center for collective use "Nano-Center" VIM confirmed the possibility of effective recovery of the gear pump by electric spark treatment.

Cryotherapy and its Correlates to Functional Performance. A Brief Preview

2013 ◽  
Vol 22 (3-4) ◽  
pp. 229-254
Author(s):  
Márcio Luís Pinto Domingues
Keyword(s):  
Motor Performance ◽  
English Language ◽  
Randomized Clinical Trials ◽  
Functional Performance ◽  
Cold Treatment ◽  
Original Research ◽  
Data Synthesis ◽  
Recovery Method ◽  
Cochrane Reviews ◽  
Evidence Database

AbstractObjective:To search the English language literature for original research addressing the effect of cryotherapy on motor performance and recovery.Data Sources:We searched MEDLINE, the Physiotherapy Evidence Database, SPORT Discus, Pubmed, and the Cochrane Reviews database, from 1976 to 2009 to identify randomized clinical trials of cryotherapy, systematic reviews, original articles and methods of cryotherapy. Key words used were cryotherapy, return to participation, cold treatment, ice, injury.Data Synthesis:Brief review including assessment of cryotherapy as a tool of performance and a recovery method.Conclusions:Most studies suggest that a short rewarming time would be beneficial (a couple minutes), which is very reasonable in sports. Also, cooling techniques differ in its result accordingly to the procedures and objectives used. Finally, the type of tissue cooled plays a large role (ie. Joint vs. Muscle).

scholarly journals Experimental investigation of the displacement flow mechanism and oil recovery in primary polymer flood operations

2021 ◽  
Vol 3 (5) ◽  
Author(s):  
Ruissein Mahon ◽  
Gbenga Oluyemi ◽  
Babs Oyeneyin ◽  
Yakubu Balogun
Keyword(s):  
Relative Permeability ◽  
Oil Recovery ◽  
Polymer Flooding ◽  
Mobility Control ◽  
List Type ◽  
Motor Oil ◽  
Flow Mechanism ◽  
Fractional Flow ◽  
Recovery Method ◽  
Polymer Flood

Abstract Polymer flooding is a mature chemical enhanced oil recovery method employed in oilfields at pilot testing and field scales. Although results from these applications empirically demonstrate the higher displacement efficiency of polymer flooding over waterflooding operations, the fact remains that not all the oil will be recovered. Thus, continued research attention is needed to further understand the displacement flow mechanism of the immiscible process and the rock–fluid interaction propagated by the multiphase flow during polymer flooding operations. In this study, displacement sequence experiments were conducted to investigate the viscosifying effect of polymer solutions on oil recovery in sandpack systems. The history matching technique was employed to estimate relative permeability, fractional flow and saturation profile through the implementation of a Corey-type function. Experimental results showed that in the case of the motor oil being the displaced fluid, the XG 2500 ppm polymer achieved a 47.0% increase in oil recovery compared with the waterflood case, while the XG 1000 ppm polymer achieved a 38.6% increase in oil recovery compared with the waterflood case. Testing with the motor oil being the displaced fluid, the viscosity ratio was 136 for the waterflood case, 18 for the polymer flood case with XG 1000 ppm polymer and 9 for the polymer flood case with XG 2500 ppm polymer. Findings also revealed that for the waterflood cases, the porous media exhibited oil-wet characteristics, while the polymer flood cases demonstrated water-wet characteristics. This paper provides theoretical support for the application of polymer to improve oil recovery by providing insights into the mechanism behind oil displacement. Graphic abstract Highlights The difference in shape of relative permeability curves are indicative of the effect of mobility control of each polymer concentration. The water-oil systems exhibited oil-wet characteristics, while the polymer-oil systems demonstrated water-wet characteristics. A large contrast in displacing and displaced fluid viscosities led to viscous fingering and early water breakthrough.

scholarly journals A New Upper Bound for Sampling Numbers

2021 ◽  
Author(s):  
Nicolas Nagel ◽  
Martin Schäfer ◽  
Tino Ullrich
Keyword(s):  
Upper Bound ◽  
Reproducing Kernel ◽  
Reproducing Kernel Hilbert Space ◽  
Sampling Procedure ◽  
Compact Embedding ◽  
Recovery Method ◽  
Grid Sampling ◽  
Integrable Functions ◽  
Random Draw ◽  
Square Integrable Functions

AbstractWe provide a new upper bound for sampling numbers $$(g_n)_{n\in \mathbb {N}}$$ ( g n ) n ∈ N associated with the compact embedding of a separable reproducing kernel Hilbert space into the space of square integrable functions. There are universal constants $$C,c>0$$ C , c > 0 (which are specified in the paper) such that $$\begin{aligned} g^2_n \le \frac{C\log (n)}{n}\sum \limits _{k\ge \lfloor cn \rfloor } \sigma _k^2,\quad n\ge 2, \end{aligned}$$ g n 2 ≤ C log ( n ) n ∑ k ≥ ⌊ c n ⌋ σ k 2 , n ≥ 2 , where $$(\sigma _k)_{k\in \mathbb {N}}$$ ( σ k ) k ∈ N is the sequence of singular numbers (approximation numbers) of the Hilbert–Schmidt embedding $$\mathrm {Id}:H(K) \rightarrow L_2(D,\varrho _D)$$ Id : H ( K ) → L 2 ( D , ϱ D ) . The algorithm which realizes the bound is a least squares algorithm based on a specific set of sampling nodes. These are constructed out of a random draw in combination with a down-sampling procedure coming from the celebrated proof of Weaver’s conjecture, which was shown to be equivalent to the Kadison–Singer problem. Our result is non-constructive since we only show the existence of a linear sampling operator realizing the above bound. The general result can for instance be applied to the well-known situation of $$H^s_{\text {mix}}(\mathbb {T}^d)$$ H mix s ( T d ) in $$L_2(\mathbb {T}^d)$$ L 2 ( T d ) with $$s>1/2$$ s > 1 / 2 . We obtain the asymptotic bound $$\begin{aligned} g_n \le C_{s,d}n^{-s}\log (n)^{(d-1)s+1/2}, \end{aligned}$$ g n ≤ C s , d n - s log ( n ) ( d - 1 ) s + 1 / 2 , which improves on very recent results by shortening the gap between upper and lower bound to $$\sqrt{\log (n)}$$ log ( n ) . The result implies that for dimensions $$d>2$$ d > 2 any sparse grid sampling recovery method does not perform asymptotically optimal.

scholarly journals Robust Secret Image Sharing Resistant to Noise in Shares

2021 ◽  
Vol 17 (1) ◽  
pp. 1-22
Author(s):  
Xuehu Yan ◽  
Lintao Liu ◽  
Longlong Li ◽  
Yuliang Lu
Keyword(s):  
Chinese Remainder Theorem ◽  
Recovery Phase ◽  
Error Correcting Codes ◽  
Secret Image Sharing ◽  
Data Loss ◽  
Least Significant Bit ◽  
Recovery Method ◽  
Secret Image ◽  
Image Sharing ◽  
Salt And Pepper

A secret image is split into   shares in the generation phase of secret image sharing (SIS) for a  threshold. In the recovery phase, the secret image is recovered when any   or more shares are collected, and each collected share is generally assumed to be lossless in conventional SIS during storage and transmission. However, noise will arise during real-world storage and transmission; thus, shares will experience data loss, which will also lead to data loss in the secret image being recovered. Secret image recovery in the case of lossy shares is an important issue that must be addressed in practice, which is the overall subject of this article. An SIS scheme that can recover the secret image from lossy shares is proposed in this article. First, robust SIS and its definition are introduced. Next, a robust SIS scheme for a  threshold without pixel expansion is proposed based on the Chinese remainder theorem (CRT) and error-correcting codes (ECC). By screening the random numbers, the share generation phase of the proposed robust SIS is designed to implement the error correction capability without increasing the share size. Particularly in the case of collecting noisy shares, our recovery method is to some degree robust to some noise types, such as least significant bit (LSB) noise, JPEG compression, and salt-and-pepper noise. A theoretical proof is presented, and experimental results are examined to evaluate the effectiveness of our proposed method.

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