scholarly journals Impacts of Absorber Loadings on Simulating the Multipath Channel in a Reverberation Chamber

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Xin Zhou ◽  
Zhangdui Zhong ◽  
Xin Bian ◽  
Ruisi He ◽  
Ke Guan ◽  
...  
Keyword(s):  
Efficient Method ◽  
Multipath Channels ◽  
Delay Spread ◽  
Mean Square ◽  
Reverberation Chamber ◽  
Rms Delay Spread ◽  
Reverberation Chambers ◽  
Digitally Modulated ◽  
Quality Measurements

In reverberation chambers, the multipath channels with different delay characteristics can be generated by loading the chamber with different amounts of absorbers. This paper investigates the impacts of absorber loadings on the delay characteristics based on realistic measurements. An efficient method for estimating the root-mean-square (rms) delay spread in the chamber is presented. Furthermore, it is found that the chamber loadings also significantly affect the quality of a digitally modulated signal and the corresponding modulation quality measurements are performed.

First flush effects in an urban catchment area in Aalborg

1998 ◽  
Vol 37 (1) ◽  
pp. 251-257 ◽  
Author(s):  
Torben Larsen ◽  
Kirsten Broch ◽  
Margit Riis Andersen
Keyword(s):  
Water Quality ◽  
Catchment Area ◽  
Quality Parameters ◽  
Average Concentration ◽  
First Flush ◽  
Storm Events ◽  
Urban Catchment ◽  
Discharge Measurements ◽  
Quality Measurements

The paper describes the results of measurements from a 2 year period on a 95 hectare urban catchment in Aalborg, Denmark. The results of the rain/discharge measurements include 160 storm events corresponding to an accumulated rain depth of totally 753 mm. The water quality measurements include 15 events with time series of concentration of SS, COD, BOD, total nitrogen and total phosphorus. The quality parameters showed significant first flush effects. The paper discusses whether either the event average concentration or the accumulated event mass is the most appropriate way to characterize the quality of the outflow.

scholarly journals PHY, MAC, and RLC Layer Based Estimation of Optimal Cyclic Prefix Length

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4796
Author(s):  
Adriana Lipovac ◽  
Vlatko Lipovac ◽  
Borivoj Modlic
Keyword(s):  
Error Recovery ◽  
Cyclic Prefix ◽  
Closed Form Expression ◽  
Delay Spread ◽  
Radio Link ◽  
Medium Access ◽  
Power Delay Profile ◽  
Rms Delay Spread ◽  
Industry Standard ◽  
New Radio

This work is motivated by growing evidence that the standard Cyclic Prefix (CP) length, adopted in the Long Term Evolution (LTE) physical layer (PHY) specifications, is oversized in propagation environments ranging from indoor to typical urban. Although this ostensibly seems to be addressed by 5G New Radio (NR) numerology, its scalable CP length reduction is proportionally tracked by the OFDM symbol length, which preserves the relative CP overhead of LTE. Furthermore, some simple means to optimize fixed or introduce adaptive CP length arose from either simulations or models taking into account only the bit-oriented PHY transmission performance. On the contrary, in the novel crosslayer analytical model proposed here, the closed-form expression for the optimal CP length is derived such as to minimize the effective average codeblock length, by also considering the error recovery retransmissions through the layers above PHY—the Medium Access Control (MAC) and the Radio Link Control (RLC), in particular. It turns out that, for given protective coding, the optimal CP length is determined by the appropriate rms delay spread of the channel power delay profile part remaining outside the CP span. The optimal CP length values are found to be significantly lower than the corresponding industry-standard ones, which unveils the potential for improving the net throughput.

scholarly journals Validation and psychometric evaluation of the Dutch person-centred care of older people with cognitive impairment in acute care (POPAC) scale

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Annette Keuning-Plantinga ◽  
Evelyn J. Finnema ◽  
Wim Krijnen ◽  
David Edvardsson ◽  
Petrie F. Roodbol
Keyword(s):  
Factor Analysis ◽  
Cognitive Impairment ◽  
Quality Of Care ◽  
Confirmatory Factor Analysis ◽  
Older People ◽  
Root Mean Square ◽  
Acute Care ◽  
Mean Square ◽  
Confirmatory Factor

Abstract Background Person-centred care is the preferred model for caring for people with dementia. Knowledge of the level of person-centred care is essential for improving the quality of care for patients with dementia. The person-centred care of older people with cognitive impairment in acute care (POPAC) scale is a tool to determine the level of person-centred care. This study aimed to translate and validate the Dutch POPAC scale and evaluate its psychometric properties to enable international comparison of data and outcomes. Methods After double-blinded forward and backward translations, a total of 159 nurses recruited from six hospitals (n=114) and via social media (n=45) completed the POPAC scale. By performing confirmatory factor analysis, construct validity was tested. Cronbach’s alpha scale was utilized to establish internal consistency. Results The confirmatory factor analysis showed that the comparative fit index (0.89) was slightly lower than 0.9. The root mean square error of approximation (0.075, p=0.012, CI 0.057–0.092) and the standardized root mean square residual (0.063) were acceptable, with values less than 0.08. The findings revealed a three-dimensional structure. The factor loadings (0.69–0.77) indicated the items to be strongly associated with their respective factors. The results also indicated that deleting Item 5 improved the Cronbach’s alpha of the instrument as well as of the subscale ‘using cognitive assessments and care interventions’. Instead of deleting this item, we suggest rephrasing it into a positively worded item. Conclusions Our findings suggest that the Dutch POPAC scale is sufficiently valid and reliable and can be utilized for assessing person-centred care in acute care hospitals. The study enables nurses to interpret and compare person-centred care levels in wards and hospital levels nationally and internationally. The results form an important basis for improving the quality of care and nurse-sensitive outcomes, such as preventing complications and hospital stay length.

scholarly journals Quality of wood in the stands of poplar clones

2008 ◽  
Vol 54 (No. 1) ◽  
pp. 9-16
Author(s):  
R. Petráš ◽  
J. Mecko ◽  
V. Nociar
Keyword(s):  
Root Mean Square Error ◽  
Systematic Error ◽  
Mean Square Error ◽  
Statistical Tests ◽  
Mean Square ◽  
Poplar Clones ◽  
Mean Diameter ◽  
Empirical Material ◽  
Relative Root

The results obtained in research on the quality of raw timber by means of the structure of assortments for the stands of poplar clones Robusta and I-214 are presented in the paper. Models for an estimation of the structure of basic assortments of poplar stands were constructed separately for each clone in dependence on mean diameter, quality of stems, and damage to stems in the stand. The clone Robusta has higher proportions of higher-quality assortments than the clone I-214. The accuracy of models was determined on empirical material. It was confirmed by statistical tests that the models did not have a systematic error. The relative root mean-square error for main assortments of the clone I-214 is 15–27% and Robusta 13–24%.

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