A forward scattering UTD method for determining signals from GSM base stations in urban

Passive radar is a kind of that without its own transmitter and receive the thermal emission energy of an object or its source of microwave energy reflected from the radar to detect targets. The widely distributed GSM base station signals have GMSK frequency modulation characteristics, these signals can be used as a passive radar radiation source for its ambiguity function diagram with axes at a distance and no ambiguity in Doppler shift and the high side-lobe and so on. Multi-base stations passive radar positioning system is one of the important research area. According to the urban low-altitude air defense warning system development, this paper do some researches on line and plane intersection algorithm for passive location and tracking, based on dual-GSM base stations. Meanwhile, probe into the passive tracking technics by utlizing the State-Dependent Riccati Equation Filter tracking algorithm under the dual GSM base stations. Experiments shows that the algorithms have better positioning accuracy, high efficiency and practical value.

Deployment of Gigabit Ethernets in metropolitan areas creates new opportunities to save costs by converging data and telephone services. The primary question of our study is whether emerging metropolitan networks can meet the QoS requirements necessary to connect GSM and UMTS base stations. These requirements on delay, jitter, and loss are significantly more stringent than the ones for VoIP and have to be met at the presence of bursty cross traffic. Therefore, we have probed ETH's campus network which spans the metropolitan area of Zurich with traffic comparable to encapsulated E1 traffic from base stations and have measured perceived QoS. Our findings show that the campus network generally meets the QoS requirements. However, the perceived QoS degrades with increasing network utilization.To further investigate the impact of the configuration of Ethernet switches on perceived QoS, we have conducted a simulation study. The results show that the perceived QoS is better when switch buffers are limited to small sizes of 1 MB compared to setups where the number of frames in the buffer is limited. From these results we infer that metropolitan Gigabit Ethernets are well suited for connecting GSM and UMTS base stations.

In this work a system is proposed that utilizes an unmanned aerial vehicle (UAV) to search and rescue trapped victims using their mobile phones. The systems consists of two parts, a ground station (GS) and an airborne station (AS). The GS provides a downlink to the UAV, a GSM base station along with antenna equipment and a mobile network jamming device. By using a smart approach to block the synchronization sequences of all base stations in range, the mobile phones of the victims to be located are switching to an emergency fallback mode. In this mode the phones connect to the strongest base station in range, thus the one provided by the GS. By initiating a call to the corresponding phone the AS can localize it using direction-of-arrival detection with a 9-channel phase coherent receiver system.

This paper addresses the problem of allocating frequencies in a GSM-based home base station (HBS) system. A novel solution called total frequency hopping (TFH) is presented in order to overcome the frequency allocation and the inter-HBS synchronisation problems. The HBS system will use the same frequency band as the overlaying GSM network and thus creates more interference to it. The simulation results reveal that the negative impact of the underlying HBS system on the GSM network performance is minimal provided that the HBS transmission (TX) power is reasonable low. The TX power cannot be arbitrarily low, however, since the HBS system must be able to function in the presence of the interference from the overlaying high power GSM network. When the power ratio between GSM base station and HBS is around 40 dB, the both networks can co-exist at the same frequency band.

We describe the software implementation of a GSM base station and consider the performance of each of its radio interface components. The performance of each software module is evaluated using both a % CPU metric and a processor-independent metric based on SPEC benchmarks. These results can be used to dimension systems, e.g., to estimate the number of GSM channels that can be supported by a given processor configuration, and to predict the impact of future processor enhancements on base station capacity.

This paper aims to provide an alternative green energy source for a remote GSM base station. To achieve this, a hybrid renewable energy (RE) plant is proposed, comprising a wind turbine, photovoltaic panels, and a fuel cell (incorporated with an electrolyzer and a hydrogen tank for the production and uniform supply of hydrogen). The system will be controlled logically by a power flow controller which will help to provide continuous power to the base station by application of economic optimization of power generation. The hybrid system and the associated load (GSM base Station) are simulated using the HOMER software and required analyses carried out. The simulation results show that renewable energy sources are feasible solutions to reducing air contaminants and pollutants (such as SO 2 & CO 2 ) produced by sources like diesel generators which also serve as an alternate source of energy for a remote GSM base station.

A GSM 900 MHz vertically polarised multibeam antenna testbed is presented incorporating a thin 4 beam microstrip planar antenna, a GSM mobile, a GSM base station (BS) a DSP and a personal computer (PC) to control the measurement procedure. The multibeam antenna covers 120/spl deg/ in azimuth with 4 beams offering an impedance bandwidth >10%, a minimum gain of 15.8 dBi for each beam and has dimensions of 710/spl times/800/spl times/12 mm. The static beamforming is performed at the radio frequency (RF). The results demonstrate a carrier to interference (C/I) improvement together with increased received signal strength indication (RSSI).

It is shown that multiple complementary techniques for trading BER performance for cost reduction in the Viterbi algorithm for multiple-input/multiple-output joint demodulation can be merged to obtain substantial and efficient cost reduction. Quantitative results for application to the separation of GSM and IS-136 cochannel signals are presented. It is shown that up to six signals can be separated at a GSM base station with BER of 10% before decoding gain with only a single dual-polarized antenna and E/sub b//N/sub o/=10 dB in real time on a Compaq 1 GHz ES-40 server, with cost savings of up to four orders of magnitude. It is also shown that for a specified BER and number of signals, the cost of MIMO demodulation decreases as the number of sensors increases. Finally, it is shown that for a fixed computational cost, BER decreases by a factor of eight, on average, for each sensor added.

Long term skeletal and dental changes between tooth-anchored versus Dresden bone-anchored rapid maxillary expansion using CBCT images in adolescents: Randomized clinical trial

A stereotaxic brain atlas of the basal ganglia and thalamus of Macaca fascicularis presented here is designed with a surgical perspective. In this regard, all coordinates have been referenced to a line linking the anterior and posterior commissures (ac–pc line) and considering the center of the ac at the midline as the origin of the bicommissural space. The atlas comprises of 43 different plates (19 coronal levels, 10 sagittal levels and 14 horizontal levels). In addition to ‘classical’ cyto- and chemoarchitectural techniques such as the Nissl method and the acetylcholinesterase stain, several immunohistochemical stains have been performed in adjacent sections, including the detection of tyrosine hydroxylase, enkephalin, neurofilaments, parvalbumin and calbindin. In comparison to other existing stereotaxic atlases for M. fasicularis, this atlas has two main advantages: firstly, brain cartography is based on a wide variety of cyto- and chemoarchitectural stains carried out on adjacent sections, therefore enabling accurate segmentation. Secondly and most importantly, sagittal and horizontal planes are included. Sagittal planes are very useful for calculating oblique trajectories, whereas, clinical researchers engaged in neuroimaging studies will be more familiar with horizontal sections, as they use horizontal (also called “axial”) brain images in their daily routine of their clinical practices.

In this paper, we present a new robust, fast, and accurate deconvolution algorithm for correcting noise disturbed measurements and eliminating the influence of the resolution filter of a spectrum analyzer used for EM-field measurements around a GSM and UMTS base station. Our purpose is to be able to determine immediately the field values at a measurement site. Therefore the algorithm has to be fast and accurate. Furthermore, because of the presence of noise, our algorithm has to be robust. Our algorithm that uses windowing and filtering meets those demands and reduces the present noise by an additional convolution with a square wave function.

Funding Acknowledgements Type of funding sources: None. Introduction Pericarditis is a relatively rare disease with a global burden. Despite its strong association with adverse cardiovascular outcomes, identification of patients at risk of future heart failure or arrhythmic events is difficult. In the following study, automated electrocardiogram (ECG) variables were used to predict new onset ventricular tachycardia/fibrillation (VT/VF), atrial fibrillation (AF) and heart failure with reduced ejection fraction (HF) in an Asian cohort of pericarditis patients. Purpose Assessing the use of automated ECG parameters to predict prognosis in pericarditis patients. Methods Consecutive patients admitted to a single tertiary center in China, for a diagnosis of pericarditis between 1st January 2005 and 31st December 2019, were included. Patients with existing AF or HF were excluded. The follow-up period was until the 31st December 2020, or death. Cox regression was applied to identify significant predictors of the incident VT/VF, AF or HFrEF. Results A total of 874 patients were included. The cohort was 57% male and had a median age of 59 (IQR: 50-70) years old. During follow-up, 57 patients (6.5%), 156 (17.8%) and 168 (19.2%) suffered from VT/VF, AF and HF, respectively. Cox regression identified baseline VT/VF, terminal angle of the QRS vector in the transverse plane, mean QRS duration and mean QTc intervals as significant predictors of incident VT/VF events, with only the foremost maintaining significance in multivariate analysis. In contrast, baseline age, prior diagnoses of hypertension, malignancy and atrial flutter, initial angle and magnitude of the QRS vector in the transverse plane, P-wave and QRS axis in the frontal plane, ST segment axis in the frontal and horizontal planes, mean PT interval, mean PR segment duration and QTc intervals were all univariate predictors of incident AF, albeit only baseline age and initial angle of the QRS vector in the transverse plane retained significance after multivariate adjustment. As it pertains to new-onset HFrEF, several clinical and electrocardiographic parameters demonstrated an association in univariate analysis, with history of hypertension, history of sudden cardiac death (SCD), initial QRS angle in transverse plane, initial 40ms QRS complex axis, ST-segment axis in the horizontal plane, T-wave frontal axis and atrial rate all showcasing significant relationships in multivariate analysis. Conclusions AF and HFrEF are relatively common complications, whilst VT/VF occurs less frequently in the context of pericarditis. Different clinical and ECG predictors of these outcomes were identified. Future studies are still needed to evaluate their use for risk stratification in the clinical setting.

We discuss the optimization and design of a single-layer, single-patch antenna element for base station array antennas. Such an element should have a minimum of 10% bandwidth and preferably a return loss of 20 dB or more. The antennas used in base stations for mobile communications usually consists of linear arrays of radiating elements in order to achieve the desired pattern: narrow beamwidth in the vertical plane and a broad beam in the horizontal plane. Other aspects of the pattern are also important: constant beam peak angle over the frequency band (i.e. no beam squint), suppression of sidelobes above the main beam and null-fill below the main beam to ensure coverage close to the base station site. For the array to meet these requirements over the frequency bandwidth, it is important to maintain good control over the phase and amplitude distribution to the elements. Furthermore, due to the high power used and the increasing demand for low intermodulation levels, the use of power dividers which provide isolation between the output ports, such as the Wilkinson divider or the 90/spl deg/ hybrid, is very limited. Therefore, any impedance mismatch at the elements will disturb the power distribution of the array and degrade the pattern. The above considerations means that the usual patch antenna designs presented, where a VSWR<2 over the band, are inadequate for use in a base station antenna array. In fact, even if an input VSWR of 1.5 (14 dB return loss) is acceptable for the array, the elements should preferably be matched to a 20 dB return loss to ensure pattern stability.

Individual route choice and decision responses in fire evacuation scenarios using immersive virtual simulations

Summary The radiation of tyre noise is computed using a hybrid integral/ beam tracing approach called GRIM. It is simply an integral over the vibrating tyre, of the product of the known velocity by the full Green function which takes into account all the multiple reflections and diffraction between tyre, ground and car body. This Green function can be calculated by means of a beam tracing program named ICARE -which can deal with curved surfaces and multiple diffraction. This approach makes the link between tyre models and reception points well outside the car. In order to deal with small scale phenomena, close to contact, a combined use of BEM and beam tracing is showed to bypass the limitations of both geometrical and BEM approaches. PACS no.43.28.Js