Matrix Completion with Noise via Leveraged Sampling

Many matrix completion methods assume that the data follows the uniform distribution. To address the limitation of this assumption, Chen et al. \cite{Chen20152999} propose to recover the matrix where the data follows the specific biased distribution. Unfortunately, in most real-world applications, the recovery of a data matrix appears to be incomplete, and perhaps even corrupted information. This paper considers the recovery of a low-rank matrix, where some observed entries are sampled in a \emph{biased distribution} suitably dependent on \emph{leverage scores} of a matrix, and some observed entries are uniformly corrupted. Our theoretical findings show that we can provably recover an unknown $n\times n$ matrix of rank $r$ from just about $O(nr\log^2 n)$ entries even when the few observed entries are corrupted with a small amount of noisy information. Empirical studies verify our theoretical results

Game Model for “Shortage of Logistics” in Online Shopping in Service Engineering

AbstractThis paper analyzes the imbalance between e-commerce and logistics service by using factor sub-game perfect Nash equilibrium as an analytical tool from the view of system and links up the bargaining process between sellers and express enterprise involved in service engineering during online shopping with discount factor. The change of interests between sellers and express enterprise is systematically analyzed from the perspective of discount factor on the equilibrium solution through the application of model towards service engineering during holidays online shopping. Finally it is concluded that discount factor is a key factor influencing the express fee between sells and express enterprise in logistic system, and some recommendations are put forward accordingly

Design of flexible track and kinematics simulation of inspection robot in fully-mechanized mining face

The problems of narrow space, frequent operation of equipment and complex positional relationship in coal mine fully-mechanized mining face make it difficult for the conventional inspection robot to run directly on the mining face and automated monitoring. According to the requirements of working conditions, combined with the environment and the action characteristics of equipment group, the design requirements of working face inspection track are proposed. A new type of flexible track for cross-seat inspection robot is designed by using modular design, simulation, and prototype test methods to realize the installation and adjustment of the working face environment and the adaptive compensation of the track itself when the installation equipment moves and deforms. Firstly, the mechanical structure of the flexible track of the inspection robot is designed and the installation operation mode is determined. Secondly, taking the track spanning on the side of the cable groove of the scraper conveyor as an example, the bending and pitching deformation of the scraper conveyor under three different working conditions of straightness, bending and fluctuation are analyzed and the kinematics simulation of the flexible track is carried out. Under three working conditions, the track can be completed with horizontal bending 0~5.4°, vertical inclination of 0~6° and telescopic deformation 0~120 mm with the working face equipment to meet the actual working conditions. When the inspection robot on board passes through the flexible track under three different working conditions, it can always maintain uniform linear motion in the main operating direction, and the horizontal or vertical direction fluctuates in the flexible transition section, and the amplitude of the fluctuation is within the safe allowable range. Finally, the physical prototype of the flexible track and the test platform of the working face are built to verify the performance of the flexible track of the working face inspection robot. The results show that the flexible track structure is designed reasonably and can be adapted to different working conditions of the mining face inspection. It is of great significance to realize the inspection of the robot in the fully mechanized working face under the coal mine

The role of connectivity in significant bandgap narrowing for fused-pyrene based non-fullerene acceptors toward high-efficiency organic solar cells

Great attention has been paid to developing low bandgap non-fullerene acceptors (NFAs) for matching wide bandgap donor polymers to increase the photocurrent and therefore the power conversion efficiencies (PCEs) of NFA organic solar cells, while pyrene-core based acceptor-donor-acceptor (A-D-A) NFAs have been mainly reported via the 2,9-position connection due to their bisthieno[3′,2′-b']thienyl[a,h]pyrene fused via a five-membered ring bridge at the ortho-position of pyrene as the representative one named FPIC5, which has prohibited further narrowing their energy gap. Herein, an acceptor FPIC6 was exploited by creating the 1,8-position connection through fusing as bisthieno[3′,2′-b′]thienyl[f-g,m-n]pyrene linked at the bay-position via a six-membered bridge, with enhanced push-pull characteristics within such A-D-A structure. As a structural isomer of FPIC5, FPIC6 exhibited a much lower bandgap of 1.42 eV (1.63 eV for FPIC5). Therefore, the photocurrent and PCE of PTB7-Th:FPIC6 cells were improved to 21.50 mA cm-2 and 11.55%, respectively, due to the balanced mobilities, better photoluminescence quenching efficiency and optimized morphology, which are both ∼40% better than those of PTB7-Th:FPIC5 cells. Our results clearly proved that a pyrene fused core with 1,8-position connection with electron-withdrawing end groups instead of 2,9-position connection is an efficient molecular design strategy to narrow the optical bandgap and improve the photovoltaic performance of NFA based OSCs

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Study on Water Rights Allocation of Irrigation Water Users in Irrigation Districts of the Yellow River Basin

With the increasingly serious problems of water security and water shortage in the Yellow River Basin, the establishment of a fair and efficient water rights distribution system is an important way to improve water resource utilization efficiency and achieve high-quality development. In this paper, a double-level water rights allocation model of national canals–farmer households in irrigation districts is established. The Gini coefficient method is used to construct the water rights allocation model among farmer households based on the principle of fairness. Finally, the Wulanbuhe Irrigation Area in the Hetao Irrigation District is taken as an example. Results show that the allocated water rights of the national canals in the irrigation district are less than the current; for example, water rights of the Grazing team (4) canal are reduced by 73,000 m3 than before, in which water rights of farmer households 1, 2, 3, and 4 obtain compensation and 5, 6, 7, and 8 are cut by the water rights allocation model and the Gini coefficient is reduced from 0.1968 to 0.1289. The research has fully tapped the water-saving potential of irrigation districts, improved the fairness of initial water rights distribution, and can provide a scientific basis for the development of water rights allocation of irrigation water users in irrigation districts of the Yellow River Basin

Study on Water Rights Allocation of Irrigation Water Users in Irrigation Districts of the Yellow River Basin

With the increasingly serious problems of water security and water shortage in the Yellow River Basin, the establishment of a fair and efficient water rights distribution system is an important way to improve water resource utilization efficiency and achieve high-quality development. In this paper, a double-level water rights allocation model of national canals–farmer households in irrigation districts is established. The Gini coefficient method is used to construct the water rights allocation model among farmer households based on the principle of fairness. Finally, the Wulanbuhe Irrigation Area in the Hetao Irrigation District is taken as an example. Results show that the allocated water rights of the national canals in the irrigation district are less than the current; for example, water rights of the Grazing team (4) canal are reduced by 73,000 m3 than before, in which water rights of farmer households 1, 2, 3, and 4 obtain compensation and 5, 6, 7, and 8 are cut by the water rights allocation model and the Gini coefficient is reduced from 0.1968 to 0.1289. The research has fully tapped the water-saving potential of irrigation districts, improved the fairness of initial water rights distribution, and can provide a scientific basis for the development of water rights allocation of irrigation water users in irrigation districts of the Yellow River Basin