Modeling the Behavior of Multipath Components Pertinent to Indoor Geolocation

Recently, a number of empirical models have been introduced in the literature for the behavior of direct path used in the design of algorithms for RF based indoor geolocation. Frequent absence of direct path has been a major burden on the performance of these algorithms directing researchers to discover algorithms using multipath diversity. However, there is no reliable model for the behavior of multipath components pertinent to precise indoor geolocation. In this dissertation, we first examine the absence of direct path by statistical analysis of empirical data. Then we show how the concept of path persistency can be exploited to obtain accurate ranging using multipath diversity. We analyze the effects of building architecture on the multipath structure by demonstrating the effects of wall length and wall density on the path persistency. Finally, we introduce a comprehensive model for the spatial behavior of multipath components. We use statistical analysis of empirical data obtained by a measurement calibrated ray-tracing tool to model the time-of- arrival, angle-of-arrival and path gains. The relationship between the transmitter-receiver separation and the number of paths are also incorporated in our model. In addition, principles of ray optics are applied to explain the spatial evolution of path gains, time-of-arrival and angle-of-arrival of individual multipath components as a mobile terminal moves inside a typical indoor environment. We also use statistical modeling for the persistency and birth/death rate of the paths

The Elevated Soluble ST2 Predicts No-Ref ow Phenomenon in ST-Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

WOS: 000494355200004PubMed: 30996145Aim: The primary percutaneous procedure resulted in a significant improvement in the prognosis of myocardial infarction. However, no-reflow phenomenon restrains this benefit of the process. There are studies suggesting that soluble suppression of tumorigenicity (sST2) can be valuable in the diagnosis and progression of heart failure and myocardial infarction. In this study, we aimed to investigate the effect of sST2 on no-reflow phenomenon in ST-elevated myocardial infarction (STEMI). Method: This study included 379 patients (258 men; mean age, 60 +/- 11 years) who underwent primary percutaneous treatment for STEMI. sST2 levels were measured from blood samples taken at admission. Patients were divided into two groups according to Thrombolysis in Myocardial Infarction(TIMI) flow grade: group 1 consists of TIMI 0,1,2, accepted as no-reflow, and group 2 consists of TIMI 3, accepted as reflow. Results: No-reflow phenomenon occurred in 60 patients (15.8%). The sST2 level was higher in the no-reflow group (14.2 +/- 4.6 vs. 11.3 +/- 5.0, p=0.003). Moreover, regression analysis indicated that diabetes mellitus, lower systolic blood pressure, multivessel vascular disease, high plaque burden, and grade 0 initial TIMI flow rate were other independent predictors of the no-reflow phenomenon in our study. Besides, when the patients were divided into high and low sST2 groups according to the cut-off value from the Receiver operating characteristics analysis, being in the high sST2 group was associated with 2.7 times increased odds for no-reflow than being in the low sST2 group. Conclusion: sST2 is one of the independent predictors of the no-reflow phenomenon in STEMI patients undergoing primary percutaneous coronary intervention