Statistical Analysis of a Subjective QoE Assessment for VVoIP Applications

Maria-Dolores Cano,Fernando Cerdan,Sergio Almagro 한국전자통신연구원 2010 ETRI Journal Vol.32 No.6

A successful deployment of multimedia applications over wireless environments entails improving the quality of service (QoS), not only from a technical point of view, but also considering the quality of experience (QoE) from the final user′s perception. Although objective QoE measure models avoid the difficulties of subjective surveys, subjective QoE assessments are essential to understand the way users evaluate the QoS. In this work, we study the effect of a wide range of parameters on the QoE of VVoIP applications in a real wireless scenario. Through a complete statistical analysis of users′ ratings, we identify the following facts. Although the use of VVoIP in wireless networks does not yet represent an advantage for users, there are great expectations for all applications under study, and with greater popularity comes higher expectations. It is easier for respondents to identify good behavior than poor behavior. Whereas the respondents′ frequency of Internet use does not impact on the scores, respondents′ gender does. Finally, the most determining parameters of quality from a user′s perspective were instability, video quality, voice distortion, usefulness, and graphical interface.

Surgical Timing of Degenerative Mitral Regurgitation: What to Consider

Maria Consolacion Dolor-Torres,Lieng H. Ling 한국심초음파학회 2012 Journal of Cardiovascular Imaging (J Cardiovasc Im Vol.20 No.4

Severe primary mitral regurgitation (MR) is a progressive condition which engenders significant mortality and morbidity if left untreated. The optimal timing of surgery in patients with MR of degenerative origin continues to be debated, especially for those who are asymptomatic. Apart from symptoms, current authoritative guidelines recommend intervention when there is incipient left ventricular dysfunction, pulmonary hypertension or new onset atrial fibrillation. This review focuses on the asymptomatic subject with severe MR, and examines contemporary clinical decision-making and management strategies, including the 2012European guidelines on valvular heart disease. We discuss the rationale for risk stratifying the asymptomatic individual, and highlight current and novel diagnostic tools that may have a useful role, with an emphasis on echocardiographic imaging.

ON THE SEPARATION AXIOM R_T

Arnal, Maria-Dolors,Guia, Josep Department of Mathematics 1986 Kyungpook mathematical journal Vol.26 No.1

Experiences in Cryopreservation of Temperate Small Fruit Plants

Carmine Damiano,Maria Dolores. Arias Padro,Andrea Frattarelli 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Two complementary stress release processes based on departures from Omori’s law

Marisol Monterrubio,Maria-Dolors Martínez,Xavier Lana 한국지질과학협의회 2016 Geosciences Journal Vol.20 No.1

Three aftershock series in Southern California, associated with the mainshocks of Landers (1992), Northridge (1994) and Hector Mine (1999) are interpreted as the superposition of a long stress relaxation process, in agreement with the Omori’s law, and a number of short episodes with sudden stress release. These short episodes are detected as departures from the expected Omori’s law. Aftershocks following a long stress relaxation process are designed as leading aftershocks (LA) and their generation rate fits well to the modified Omori’s law (MOL). The rest of aftershocks correspond to the different episodes of sudden stress release, every one designed as a cascade (CA). Cascades are found to be characterized by four basic properties. First, although the number of aftershocks NC belonging to every cascade fluctuates greatly along the stress relaxation process, a clear positive trend of NC with the elapsed time since the mainshock is observed in the initial phase of the aftershock sequence. After a critical elapsed time, very short in comparison with the aftershock sequence length, this positive trend diminishes significantly or even becomes negative. Second, the aftershock generation rate, GR, for every cascade, is almost constant. Third, GR for the successive CAs, represented as a function of its starting time measured since the mainshock, decreases according to a power-law. Four, the validity of the Gutenberg-Richter law is preserved for the sequence of all aftershocks belonging to cascades, with values of the b-parameter quite similar to those deduced for the complete aftershock series. Additionally, some statistical and fractal (self-affine) properties of CAs are analyzed. Given that the number of aftershocks with minimum magnitudes assuring catalogue completeness ranges, for the three seismic crises, from 6,000 up to 20,000, properties concerning LA and CA can be established with a high degree of confidence. As a conclusion, a single stress relaxation process following the Omori’s law should be discarded. A physical explanation, based on the complex spatial patterns of the stress field and tectonic fractures, as well as on the two proposed relaxation processes, is qualitatively discussed.

Fractal analysis and statistics of seismic generation rates: the example of the southern California

Xavier Lana,Maria Dolors Martínez,Seyed Amir Hosseini,Carina Serra 한국지질과학협의회 2017 Geosciences Journal Vol.21 No.3

The seismic generation rate, SGR, at southern California along the 1981–2007 recording period is analysed with the main purpose of finding out whether there exist some correlations between seismic activity before, after and along aftershock sequences triggered by mainshocks of high magnitude. The possibility that a mainshock could be triggered by another neighbouring mainshock and its aftershock sequence is also investigated. The analyses are based on monthly SGR series, obtained as the number of events detected every month along the recording period considered. These monthly SGR series are derived for three aftershock areas associated with Landers (June 28, 1992, Mw = 7.3), Northridge (January 17, 1994, Mw = 6.7) and Hector Mine (October 16, 1999, Mw = 7.1) mainshocks. The most relevant features of SGR series are investigated through various techniques: 1) the rescaled range analysis and the interpretation of the Hurst exponent in terms of persistence, anti-persistence and randomness; 2) time trend estimation by the Kendall-tau algorithm and assessment of their statistical significance by the Mann-Kendall test; 3) the self-affine character, derived from semivariograms, and the Hausdorff measure; 4) autocorrelation and power spectra; 5) cross-correlation and cross-power spectra; 6) the search for the statistical distribution best reproducing the empirical probability of SGR series. Additionally, a close look at plots of epicenters within the aftershock areas, distinguishing between periods of background and aftershock activity, permits detecting some features of the seismicity. Changes on spatial patterns of seismicity suggest that the effects of tectonic stress redistribution could persist beyond an aftershock period, at short and medium distances of the mainshock. This possibility would be also in agreement with cross-correlation results for SGR series.

Creativity in Gifted & Talented Children

Mercedes Ferrando,Carmen Ferrandiz,Maria Dolores Prieto,Maria Rosario Bermejo,Marta Sainz 대한사고개발학회 2008 The International Journal of Creativity & Problem Vol.18 No.2

The aim of the research was to study the creativity of G&T children. It has been emphasised in different theories that creativity is an essential factor in the configuration and measurement of G&T students’ cognitive profile. Therefore, it is important to understand how giftedness and creativity can be identified and assessed. The assessment of creativity in G&T children mainly focuses on using TTCT to understand the complex creativity of those children. This article presents an empirical study carried out in Murcia (Spain) orientated towards comparing creativity between G&T and non-gifted or non-talented. The results indicated that gifted and creative talented children scored higher than non-G&T children. Gifted children showed greater flexibility, which means that they have a high ability to manage and process different types of information. It was also found that creatively talented children showed higher scores in originality, mental flexibility and fluency.

Aftershock sequences of three seismic crises at southern California, USA, simulated by a cellular automata model based on self-organized criticality

Marisol Monterrubio,Xavier Lana,Maria Dolors Martínez 한국지질과학협의회 2015 Geosciences Journal Vol.19 No.1

Several properties of aftershock series related to themain shocks of Landers, Northridge and Hector Mine (southern California, USA) are reproduced by theDynamic Fiber Bundle Model, DFBM. Optimum values for the three parameters governing DFBM aredetermined by searching for the best agreement of real aftershock series properties and those ofsynthetic sequences gen- erated by this model. The analysis of the model parameter values providesdetails on the underlying physical mechanism of the after- shock sequence generation. First, theratio of seismic energy radiated as seismic waves and transferred as stress-strain to adjacentfaults; second, the degree of stress heterogeneity reproducing the complex behavior of realaftershock series. Additionally, the results of simula- tions support the coexistence of two typesof relaxation processes. One of them is associated with the well-known modified Omori’s (MO) law,which involves elapsed times between consecutive after- shocks monotonically increasing; the otheris manifested by episodes of sudden stress release, with inter-event times much shorter than thosepredicted by MO law. These episodes are assumed to be a consequence of the complex distribution oftectonic stresses and fault geometry. The first process is associated to events designed as leadingaftershocks, LA. The second process generates series of events which are designed as cascades, CA. It is worth of mention that several properties con- cerning CAs can be reasonably related tocritical changes on stressfield along the simulation process.

Prognostic factors associated with local recurrence in squamous cell carcinoma of the vulva

Sara Iacoponi,Ignacio Zapardiel,Maria Dolores Diestro,Alicia Hernandez,Javier De Santiago 대한부인종양학회 2013 Journal of Gynecologic Oncology Vol.24 No.3

Objective: To analyze the prognostic factors related to the recurrence rate of vulvar cancer. Methods: Retrospective study of 87 patients diagnosed of vulvar squamous cell carcinoma diagnosed at a tertiary hospital in Madrid between January 2000 and December 2010. Results: The pathological mean tumor size was 35.1±22.8 mm, with stromal invasion of 7.7±6.6 mm. The mean free margin after surgery was 16.8±10.5 mm. Among all patients, 31 (35.6%) presented local recurrence (mean time 10 months; range, 1 to 114 months) and 7 (8%) had distant metastases (mean time, 5 months; range, 1 to 114 months). We found significant differences in the mean tumor size between patients who presented a relapse and those who did not (37.6±21.3 mm vs. 28.9±12.1 mm; p=0.05). Patients with free margins equal or less than 8 mm presented a relapse rate of 52.6% vs. 43.5% of those with free margin greater than 8 mm (p=0.50). However, with a cut-off of 15 mm, we observed a local recurrence rate of 55.6% vs. 34.5%, respectively (p=0.09). When the stromal invasion cut-off was >4 mm, local recurrence rate increased up to 52.9% compared to 37.5% when the stromal invasion was ≤4 mm (p=0.20). Conclusion: Tumor size, pathologic margin distance and stromal invasion seem to be the most important predictors of local vulvar recurrence. We consider the cut-off of 35 mm of tumor size, 15 mm tumor-free surgical margin and stromal invasion >4 mm, high risk predictors of local recurrence rate.

Long-term effectiveness of cinacalcet in non-dialysis patients with chronic kidney disease and secondary hyperparathyroidism

( Ariadna Perez-ricart ),( Maria Galicia-basart ),( Dolors Comas-sugranes ),( Josep-maria Cruzado-garrit ),( Alfons Segarra-medrano ),( Jose-bruno Montoro-ronsano ) 대한신장학회 2019 Kidney Research and Clinical Practice Vol.38 No.2

Background: Secondary hyperparathyroidism (SHPT) is a common complication of chronic kidney disease (CKD). Cinacalcet use is controversial in non-dialysis patients. Methods: This retrospective observational study recruited patients receiving cinacalcet (off-label use) in 2010 and 2011. Patients were followed for three years from the beginning of treatment using an intention-to-treat approach. Results: Forty-one patients were studied: 14 CKD stage 3 (34.1%), 21 CKD stage 4 (51.2%), and 6 CKD stage 5 (14.6%). Median baseline parathyroid hormone (PTH) was 396 (101-1,300) pg/mL. Upon cinacalcet treatment (22 ± 12 months), PTH levels decreased by ≥ 30% in 73.2% of patients (P < 0.001; 95% confidence interval [CI], 59-87%), with a mean time for response of 18.7 months (95% CI, 15.4-22.1). Sixteen patients were followed for 36 months and treated for 32 ± 9 months. Mean reduction in their PTH levels was 50.1% (P < 0.001; 95% CI, 33.8-66.4%) at 36 months, with 62.5% of patients (P < 0.001; 95% CI, 35.9-89.1%) presenting reductions of ≥ 30%. Serum calcium levels decreased from 9.95 ± 0.62 mg/dL to 9.21 ± 0.83 and 9.12 ± 0.78 mg/dL at 12 and 36 months, respectively (P < 0.001). Serum phosphorus levels increased from 3.59 ± 0.43 to 3.82 ± 0.84 at 12 months (P = 0.180), remaining so at 36 months (P = 0.324). At 12 and 36 months, 2 (12.5%) patients experienced hypocalcemia. Meanwhile, 1 (6.3%) and 4 (25.0%) patients reported hyperphosphatemia at 12 and 36 months, respectively. Conclusion: Cinacalcet remained effective for at least 36 months in non-dialysis patients with SHPT. Electrolytic disturbances were managed with concurrent use of vitamin D and its analogs or phosphate binders.