Search results for "GSM"
showing 10 items of 154 documents
Valsts parāds un ekonomiskā izaugsme
2016
Bakalaura darba tēma ir “ Valsts parāds un ekonomiskā izaugsme ”. Analizējot tādus Latvijas labklājības rādītājus kā Gini koeficients, Iekšzemes kopprodukts uz vienu iedzīvotāju pēc pirktspējas paritātes kā arī ekonomikas izaugsmes radītājus var secināt, ka Latvija stipri atpaliek no citām Eirozonas valstīm. Bet analizējot parāda apjomu un budžeta deficītu var redzēt, ka Latvija pilnībā atbilst Māstrihtas kritērijam un salīdzinot ar citām Eiropas un Pasaules attīstītām valstīm parāda un budžeta deficīts ir relatīvi neliels. Daudzām Eirozonas valstīm ir problēmas ar atbilstību Māstrihtas kritērijam. Darba mērķis : Bakalaura darba mērķis ir, pamatojoties uz iegūto informāciju, izpētīt kā vals…
Iedzīvotāju novecošanās ietekme uz Eiropas Savienības ekonomikas izaugsmi
2016
Bakalaura darba tēma ir “Iedzīvotāju novecošanās ietekme uz Eiropas Savienības ekonomikas izaugsmi”, darba mērķis - izanalizēt iedzīvotāju novecošanās ietekmi uz ekonomikas izaugsmi Eiropas Savienībā. Darba pirmajā daļā tiek apskatīta iedzīvotāju demogrāfiskās struktūras un iedzīvotāju novecošanās, kā arī ekonomikas izaugsmes būtība. Otrajā un trešajā daļā tiek analizēta Eiropas Savienības un Latvijas iedzīvotāju demogrāfiskās struktūra, novecošanās, ekonomikas izaugsmes raksturojošu un ietekmējošu rādītāju jaunākie dati un prognozes, kā arī kompleksie pasākumi ekonomikas izaugsmes un demogrāfiskās struktūras uzlabošanai. Darba rezultātā tiek atklāts, ka iedzīvotāju novecošanās pati par sev…
Human Sleep EEG under the Influence of Pulsed Radio Frequency Electromagnetic Fields
2000
Former exploratory investigations of sleep alterations due to global system for mobile communications (GSM) signals have shown a hypnotic and REM-suppressive effect under field exposure. This effect was observed in a first study using a power flux density of 0.5 W/m<sup>2</sup>, and the same trend occurred in a second study with a power flux density of 0.2 W/m<sup>2</sup>. For the present study, we applied a submaximal power flux density of 50 W/m<sup>2</sup>. To investigate putative effects of radio frequency electromagnetic fields (EMFs) of cellular GSM phones on human sleep EEG pattern, all-night polysomnographies of 20 healthy male subjects both with …
On the performance of joint processing schemes over the cluster area
2010
En este trabajo se caracterizan tres esquemas de transmisión conjunta para el enlace descendente y se compara su rendimiento dentro de un clúster de estaciones base. La motivación de este estudio es analizar el rendimiento de estos esquemas dentro del área del clúster, como un primer paso hacia el diseño de un esquema de transmisión conjunta adaptable que soporte escenarios de uso dinámicos. Cada uno de los esquemas analizados, centralizado, parcial y distribuido, requiere una cantidad diferente de conocimiento del canal disponible en el lado del transmisor, un intercambio distinto de información entre estaciones base y la retroalimentación de los usuarios. Además, estos esquemas muestran d…
An embedded diagnostic system for wheelchairs brushless drives monitoring
2006
The implementation of a microcontroller based monitoring system for the diagnosis of a brushless synchronous motor drives is presented. It finds its primarily interest on motorized wheelchair for disabled people. The embedded system mainly controls all the principal parameters of the electrical drives together with the power supply system. Pre-failure and failure conditions are routinely logged and, depending on the malfunction severity, alarm messages are created and sent to a remote base station by using the GSM wireless network.
Narrowband digital filtering with random frequency hopping spread spectrum
2014
International audience; In digital signal filtering, channels with narrow bandwidth need high order digital filter to be selected without introducing modulation errors. If a carrier randomly switches from a channel to another as in military applications, or some civilian communication standards, it is necessary to detect and estimate these jumps before transposing and analyzing signals in the baseband. This paper presents a real time solution to filter narrow band signals with random frequency hopping spread spectrum. The proposed method is based on three steps. Firstly, the detection of Signal Frequency Hopping (SFH) using the Fast Fourier Transform (FFT), an algorithm to estimate the Domi…
Analysis of proposals to reduce SAR levels from GSM terminals
2002
Is wireless communication dangerous? In recent years some scientists and lay people have expressed alarm at the possible harm mobile phones could cause to the user's health, even cancer. Handset terminals must meet standard limits based in SAR measurements. In this paper we present several proposals to minimize SAR values computed over a numerical user's head model using absorbent materials and new generation antennas.
Analysis of Spatial Disparities by a Structural Equations Model
2008
This paper presents a new analytical framework for assessing spatial disparities among countries. It takes for granted that the analysis of a country’s performance cannot be limited solely to either economic or social factors. The aim of the paper is to combine relevant economic and non-economic (mainly social) aspects of a country’s performance in an integrated logical framework. Based on this idea, a structural simultaneous equation model will be presented and estimated in order to explore the direction of the causal relationship between the economic and the non-economic aspects of a country’s performance. Furthermore, an exploration of the trajectory that each country has registered over…
Low-Power Wide-Area Networks for Sustainable IoT
2019
Low-power wide-area (LPWA) networks are attracting extensive attention because of their abilities to offer low-cost and massive connectivity to Internet of Things (IoT) devices distributed over wide geographical areas. This article provides a brief overview on the existing LPWA technologies and useful insights to aid the large-scale deployment of LPWA networks. Particularly, we first review the currently competing candidates of LPWA networks, such as narrowband IoT (NB-IoT) and long range (LoRa), in terms of technical fundamentals and large-scale deployment potential. Then we present two implementation examples on LPWA networks. By analyzing the field-test results, we identify several chall…
Accurate detection and characterization of corner points using circular statistics and fuzzy clustering
1998
Accurate detection and characterization of corner points in grey level images is considered as a pattern recognition problem. The method considers circular statistic tests to detect 2D features. A fuzzy clustering algorithm is applied to the edge orientations near the prospective corners to detect and classify them. The method is based on formulating hypotheses about the distribution of these orientations around an edge, corner or other 2-D feature. The method may provide accurate estimates of the direction of the edges that converge in a corner, along with their confidence intervals. Experimental results show the method to be robust enough against noise and contrast changes. Fuzzy membersh…