Performance evaluation of random power capture on mobile communicationsR

SUMMARY Power assignment schemes are man-made methods to enhance the capture e!ect of radio communications. In a previous study, Wen and Yang investigated the combined capture e!ect of the "xed power assignment scheme, Rayleigh fading, and near}far e!ect on the performance of packet radios. The performance analysis was limited to an in"nite population environment. This assumption is reasonable for a conventional packet radio system with a vast service area. However, for a cellular mobile system, a "nite population model should be used. In this paper, we analyse the combined natural and man-made capture e!ect on the performance of a cellular system with "nite population in each cell. A random power assignment scheme is adopted to produce the man-made capture. The system throughput and delay are carried out by a Markov model. Some numerical calculations are used to demonstrate the degree of performance improvement

The relative importance of head, flux, and prior information in hydraulic tomography analysis

Using cross-correlation analysis, we demonstrate that flux measurements at observation locations during hydraulic tomography (HT) surveys carry nonredundant information about heterogeneity that are complementary to head measurements at the same locations. We then hypothesize that a joint interpretation of head and flux data, even when the same observation network as head has been used, can enhance the resolution of HT estimates. Subsequently, we use numerical experiments to test this hypothesis and investigate the impact of flux conditioning and prior information (such as correlation lengths and initial mean models (i.e., uniform mean or distributed means)) on the HT estimates of a nonstationary, layered medium. We find that the addition of flux conditioning to HT analysis improves the estimates in all of the prior models tested. While prior information on geologic structures could be useful, its influence on the estimates reduces as more nonredundant data (i.e., flux) are used in the HT analysis. Lastly, recommendations for conducting HT surveys and analysis are presented

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

A STUDY OF MEAN AREAL PRECIPITATION AND SPATIAL STRUCTURE OF RAINFALL DISTRIBUTION IN THE TSEN-WEN RIVER BASIN

ABSTRACT In this paper, the kriging method with stochastics was applied in order to study the spatial structure of precipitation distributions. Mean areal precipitation and the spatial structure of six storms over the TsenWen River basin were examined by semivariograms of the storms. Findings revealed topographic influences on the rainfall distributions in the study area. These impacts were reflected in the difference between the mean areal precipitation of the kriging and the Thiessen methods and the correlation structure (or range) of the rainfall distributions. The mean areal precipitation showed a difference of 2.5% in favor of the kriging method. The range of the rainfall distribution averaged about 46.17-km, a very close correlation to the downstream length, 47-km, of the Tsen-Wen River. In addition, the smaller the standard deviations of the precipitation distributions, the more appropriate it is to use the assumption of the second-order stationarity for investigating the storm structures

Identification of groundwater basin shape and boundary using hydraulic tomography

Shapes and boundary types of a groundwater basin play essential roles in the analysis of groundwater management and contaminant migration. Hydraulic tomography (HT), a recently developed new approach for high-resolution characterization of aquifers, is not only an inverse method but a logical strategy for collecting non-redundant hydraulic information. In this study, HT was applied to synthetic 2-D aquifers to investigate its feasibility to map the irregular shapes and types of the aquifer boundaries. We first used the forward model of VSAFT2 to simulate hydraulic responses due to HT surveys in the aquifer with irregular geometry and predetermined constant head conditions at some boundaries, and no-flow conditions at others. The SimSLE (Simultaneous Successive Linear Estimator) inverse model in VSAFT2 was then used to interpret the simulated HT data to estimate the spatial distribution of hydraulic properties of the aquifer using a domain with a wrong geometry surrounded by boundaries of a constant head condition. The inverse modeling experiment used steady-state and transient-states data from the HT forward simulations, and it used the same monitoring network as in the aquifer with irregular geometry to assess the ability of HT for detecting types and shapes of the boundary as well as heterogeneity in the aquifer. Results of the experiment show that no-flow boundaries, which were incorrectly treated as constant head boundaries in inverse models, were portrayed as low permeable zones of the aquifer near the boundaries. Overall, the results show that HT could delineate not only the irregular shape of the aquifer in general but also heterogeneity in the aquifer. Improvements of the estimation with prior information of transmissivity and storage coefficient was also investigated. The study shows that using homogeneous initial guess parameters resulted in a slightly better estimate than others. Moreover, this study employs Monte Carlo simulations to ensure statistically meaningful conclusions.The Scholarship from the Royal Thai Government and the Department of Groundwater Resources, Thailand, and partially supported by U.S. NSF grant EAR193175624 month embargo; available online 21 May 2020This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Saving the On-Scene Time for Out-of-Hospital Cardiac Arrest Patients: The Registered Nurses’ Role and Performance in Emergency Medical Service Teams

For out-of-hospital cardiac arrest (OHCA) patients, every second is vital for their life. Shortening the prehospital time is a challenge to emergency medical service (EMS) experts. This study focuses on the on-scene time evaluation of the registered nurses (RNs) participating in already existing EMS teams, in order to explore their role and performance in different EMS cases. In total, 1247 cases were separated into trauma and nontrauma cases. The nontrauma cases were subcategorized into OHCA (NT-O), critical (NT-C), and noncritical (NT-NC) cases, whereas the trauma cases were subcategorized into collar-and-spinal board fixation (T-CS), fracture fixation (T-F), and general trauma (T-G) cases. The average on-scene time of RN-attended cases showed a decrease of 21.05% in NT-O, 3.28% in NT-C, 0% in NT-NC, 18.44% in T-CS, 13.56% in T-F, and 3.46% in T-G compared to non-RN-attended. In NT-O and T-CS cases, the RNs’ attendance can notably save the on-scene time with a statistical significance (P=.016 and .017, resp.). Furthermore, the return of spontaneous circulation within two hours (ROSC2 h) rate in the NT-O cases was increased by 12.86%. Based on the findings, the role of RNs in the EMTs could save the golden time in the prehospital medical care in Taiwan

Characterization of basin-scale aquifer heterogeneity using transient hydraulic tomography with aquifer responses induced by groundwater exploitation reduction

This study exploits aquifer responses to the reduction of pumping rates at different locations in a synthetic groundwater basin as basin-scale hydraulic tomography (HT) surveys to estimate transmissivity (T) and storage coefficient (S) fields. This experiment mimics the situation of groundwater exploitation reduction in a pilot area of groundwater-overexploitation control in the North China Plain. The results of the study show that taking advantage of the groundwater exploitation reduction as HT surveys is a viable approach for basin-scale parameter estimations. Results also suggest that HT analysis should use accurate mean values of T and S for geological zones as initial guesses for the inversion of parameters. Further, we show that the T and S fields estimated from HT yield accurate predictions of the groundwater flow velocities and breakthrough curves (BTCs). However, the BTCs based on kriged and zonal mean fields are inaccurate. The predicted BTCs using homogeneous fields fail to capture the true trend of solute concentration over time. We advocate that utilizing aquifer responses induced by groundwater exploitation reduction could be a new paradigm for basin-scale aquifer characterization.National Natural Science Foundation of China (Grant No. 41901039) the China Scholarship Council (Grant No. 201808130026) Natural Science Foundation of Hebei Province (Grant No. D2019402045) the Department of Education of Hebei Province (Grant No. QN2018076) the U.S. NSF grant EAR193175624 month embargo; available online 3 June 2020This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]