An expanding mobile cellular network data transfer service offers cheaper wireless solutions for various data transfer needs. This paper presents an experimental testing of data transfer performance in 3G and 4G modes. The purpose of testing was to check the possibility of real-time and critical data transfer over the mobile cellular networks. The testing was performed in Riga in July and August 2016 using the most popular mobile service operators in Latvia: Tele2-LV, BITE-LV and LMT. The testing confirmed that the overload of Riga’s 4G networks causes serious service deterioration or even interruption. Riga’s 3G networks are more stable. However, 3G network service quality depends on a cell load. Lightly loaded 3G network meets real-time data transfer requirements of 100 ms one-way delay of the small packet traffic.
Sung-Wook Kang, Yong-Man Park, Beom-Seon Jang, Yu-Chul Jeon and Seong-Min Kim
Although the transverse butt weld method with ceramic backing strip has been widely used in various industrial fields for its fabricational convenience, it is rarely used in offshore industries since the fatigue strength of the weld joint has not been proved sufficiently. This study conducted fatigue tests for series of butt weld specimens with horizontal (2G) and vertical (3G) welding positions in order to verify the fatigue strength compared to S-N curve by DNV (Det Norske Veritas), IIW (International Institute of Welding) and Eurocode 3. The difference of the 2G specimens and the 3G specimens are investigated in terms of angular distortion and the effect on the fatigue strength are analyzed.
Remotely piloted operations of lightweight Unmanned Air Vehicles (UAV) are limited by transmitter power consumption and are always restricted to Line-of-Sight (LOS) distance. The use of mobile cellular network data transfer services (e.g. 3G HSPA and LTE) as well as long-range terrestrial links (e.g. LoraWAN) makes it possible to significantly extend the operation range of the remotely piloted UAV. This paper describes the development of a long-range communication solution for the UAV telemetry system. The proposed solution is based on (but not restricted to) cellular data transfer service and is implemented on Raspberry Pi under Gentoo Linux control. The goal of the project is to develop a flexible system for implementing optimized redundant network solutions for the Non-LOS remote control of the UAV
Well-deployed cellular networks offer a cheap wireless solution for the control channel deployment of Remote-Control Vehicles (RCV) and Unmanned Aerial Vehicles (UAV). However, a cellular data transfer service performance is affected by a different kind of User Equipment (UE) mobility. Operating conditions of UAV imply working at different altitudes, variable velocities with accelerations/decelerations and rapidly changed antennas angular position, which lead the wireless signal to be prone to negative effects. Available field measurement studies are not sufficient to provide excessive information on degradation problem causes for UEs moving along a complex trajectory. This paper presents an evaluation of the service quality of live operational 3G and LTE networks for both ground moving and flying UE. It has been found that antennas angular position variations in 3D (for example, during UAV manoeuvers) increase data transfer latency and jitter. Moreover, this effect in conjunction with higher interference at high altitudes may partially or fully block the data transfer service. This paper has been prepared to draw attention to the problem that makes the cellular data transfer service unusable for highly-manoeuvrable UAVs.
1. J. G. P. RODRIGUES, A. AGUIAR, F. VIEIRA, J. BARROS, AND J. P. S. CUNHA. 2011. A mobile sensing architecture for massive urban scanning". In: 14th International IEEE Conference on Intelligent Transportation Systems (ITSC) , pp. 1132-1137.
2. P. DESHPANDE, X. HOU, and S. R. DAS. 2010. Performance comparison of 3G and metro-scale WiFi for vehicular network access. In Proceedings of the 10th annual conference on Internet measurement - IMC '10 , p. 301.
3. H.-S. PARK, S.-H. HAN, AND J.-D. KIM
Simona Miclăuş, George Mihai, Angel Marian Aron, Cristian Mitrescu, Paul Bechet and Octavian Baltag
A dual band mobile phone model was used to check the shielding properties of an amorphous ferromagnetic textile against the radiation emitted by the handset. Two frequencies belonging to the 2nd and 3rd generation of mobile emission technologies were used, 897 MHz and 1950 MHz. The specific absorption rate (SAR) of energy deposition in a human head phantom was measured in standardized conditions. The textile contained micrometric-diameter wires of a ferromagnetic mixture embedded in a thin glass coat and weaved in a specific way. A set of fabric orientations and configurations (layering) were provided in the experiment in order to achieve a better shielding to the phone’s radiation. Compared with the non-shielded handset, SAR deposited in the head while using the fabric-covered phone could be decreased up to 30 % of its initial value – in case of 2G technology and up to 24 % – in case of 3G technology. This type of material shows one of the highest shielding efficiencies of the electric-field component in near-field exposure conditions reported until now. A cubic curve of SAR decrease in depth of the head was revealed in both uncovered and covered handset, the effect of shielding being larger at the higher frequency.
The world’s cruise corporations regularly purchase large, luxurious cruise ships. In accordance with the Cruise Line International Association, 33 new ocean cruise ships will be available on the market by 2020. These types of capital expenditures are associated with large financial outlays of up to $ 1 billion. The leading cruise corporations are not able to finance purchases of new units with their own resources and therefore look for different solutions. Available publications focus mainly on issues related to purchasing cargo ships, not cruise ships. The objective of the article is to identify sources of funding of new cruise ships. Our analysis identifies the average capital expenditure associated with purchasing new cruise ships and factors that influence it. The most popular methods for raising such capital are also provided. Our research methodology relies on data exploration method, a desk research method and comparative analysis.
This article concerns the problem of formulating assumptions in scenario analysis for investments which consist of the renting out of an apartment. The article attempts to indicate the foundations for the formulation of assumptions on the basis of observed retrospective regularities. It includes theoretical considerations regarding scenario design, as well as the results of studies on the formulation, in the past, of quantities which determined or were likely to bring closer estimate the value of the individual explanatory variables for a chosen measure of investment profitability (MIRRFCFE). The dynamics of and correlation between the variables were studied. The research was based on quarterly data from local residential real estate markets in Poland (in the six largest cities) in the years 2006 – 2014, as well as on data from the financial market.
This paper examines the characteristics of dividend paying firms in Bosnia and Herzegovina. The research is conducted on a sample of 35 largest public firms during the period of five years, from 2013 to 2017, using multiple linear regression and logistic regression. The aim of the research is to explore the internal determinants of dividend payouts and to find whether there are any deviations from empirical experiences in the world. The research results show that larger and more profitable firms are more likely to pay dividends, while more indebted and closely held firms are less likely to pay dividends. The negative relation found between the dividend decision and investment opportunities is not statistically significant. The research results also show that the size is positively associated with higher payout ratios, while the payout ratios decrease with greater use of financial leverage. Profitability, investment opportunities and ownership concentration do not affect the level of dividend distribution.