• Rural Digital Europe
• 2013-2022close
• Open Access close
• LV close
• European University of Technology close
• Rural Digital Europe close

Abstract Agriculture is the second most significant source of greenhouse gas (GHG) emissions, with approximately 24 % of Latvia’s total GHG emissions in 2014. Emissions from agricultural soils contributed major share of the total emissions – 59.6 %, enteric fermentation emissions was second largest source – 32 %. The share of manure management emissions was evaluated as 7.5 % of total emissions in the sector, remaining 0.9 % of emissions refer to liming and urea application. GHG emissions increased in 2014 by 3.3 % comparing to 2013 due to increase of cattle, sheep and fur animal numbers. Statistics also showed increase of synthetic N fertilizer consumption approximately by 4.6 %, sown area by 0.3 % and lime application to soils 42.9 % [1]. Bearing in mind significant share of agricultural emissions in total GHG emissions in Latvia and the growing emission trend the additional attention is necessary for evaluation of impacts of agriculture on the environment. The purpose of this study is to explore indicators for assessing eco-efficiency in the Latvian agriculture sector. First the paper describes methods which can be used for measuring eco-efficiency, second availability of activity data and third, presents calculations of selected indicators for eco-efficiencies.

Abstract Concerns about drinking water (DW) quality contamination during water distribution raise a need for real-time monitoring and rapid contamination detection. Early warning systems (EWS) are a potential solution. The EWS consist of multiple conventional sensors that provide the real-time measurements and algorithms that allow the recognizing of contamination events from normal operating conditions. In most cases, these algorithms have been established with artificial data, while data from real and biological contamination events are limited. The goal of the study was the event detection performance of the Mahalanobis distance method in combination with on-line DW quality monitoring sensors and manual measurements of grab samples for potential DW biological contamination scenarios. In this study three contamination scenarios were simulated in a pilot-scale DW distribution system: untreated river water, groundwater and wastewater intrusion, which represent realistic contamination scenarios and imply biological contamination. Temperature, electrical conductivity (EC), total organic carbon (TOC), chlorine ion (Cl-), oxidation–reduction potential (ORP), pH sensors and turbidity measurements were used as on-line sensors and for manual measurements. Novel adenosine-triphosphate and flow cytometric measurements were used for biological water quality evaluation. The results showed contamination detection probability from 56% to 89%, where the best performance was obtained with manual measurements. The probability of false alarm was 5–6% both for on-line and manual measurements. The Mahalanobis distance method with DW quality sensors has a good potential to be applied in EWS. However, the sustainability of the on-line measurement system and/or the detection algorithm should be improved.

Abstract The purpose of this research was to investigate a landowner’s status as a lessor in land consolidation on agricultural areas in Europe. The research was based on surveys designed for land consolidation experts from Cyprus, Finland, France, Germany, the Netherlands, Latvia, Estonia and statistical data of the areas. The lease of agricultural land is common in Europe. However, there are differences related to how common the lease is and what the rental value of land is. The variation is based on factors such as differences in the markets, historical development of the agricultural lands and current legislation. The lessors have rights as landowners in land consolidation, but in case the land is used by third parties, lessor’s status is more limited compared to other landowners’. Similarly the costs of land consolidation typically are paid by landowners, not by users. The lessors are commonly indifferent and suspicious about the land consolidation. They are occasionally suspicious, especially before or at the beginning of the process, but later on they seem to be less suspicious. The lessors’ experience of land consolidation is based commonly on a fear of additional costs for their investment.

A highly accurate ionosphere model is necessary to enable a fast and reliable coordinate determination with GNSS in real time. It is a partially ionized atmospheric region ranging up to 1,000 km height, affected by spatial variations, space weather, seasonal and solar cycle dependence. New approaches and algorithms of modelling techniques are sought to provide better solutions in the territory of Latvia. Ionospheric TEC value has large differences in Western Latvia and Eastern Latvia. Actual ionospheric map should be calculated and delivered to the surveyors near real time and published on the WEB. Delivering actual map to rover GNSS devices in a field will provide the surveyors with ionospheric conditions and allow choosing best time for surveying and making geodetic measurements with higher accuracy and reliability.

Snow should be accounted in electromagnetic fields' risk assessment, especially in Nordic countries where in winter months snow precipitation and coverage may significantly affect the propagation of microwaves. The risk assessment should be always carried out under worst case scenario conditions, including the reflective properties of the surfaces surrounding the antenna. In this study fresh snow microwave reflectance properties were investigated at the mobile communication bands from 1700 to 2700 MHz.The investigation revealed that reflection loss from snow is more dependent from the frequency than from the thickness of snow coverage. Amongst mobile communication bands, the strongest microwave reflection (reflection loss only 3.2dB) was registered at WiFi2G band. Averaging all the snow thicknesses, the highest reflection loss occurs at GSM1800UL (1710-1785 MHz) and UMTS2100DL (2110-2170 MHz) bands. The least attenuation of reflection occurs in adjacent DECT band.

Abstract The paper addresses the impact of peak-to-average power ratio (PAPR) and spectrum of the waveform, as well as load resistance on the performance of low-power harvesting device in a real-life wireless power transfer (WPT) scenario. In the current study, a combination of the classic voltage doubler circuit for RFDC conversion and premanufactured device for DC-DC conversion is used. For the investigation of conversion efficiency and harvesting device performance, three types of waveforms are used: single tone, multicarrier signals with low PAPR and multicarrier signal with high PAPR. In order to generate high-PAPR signal, subcarriers with the same amplitude and phase are summed, whereas for generation of low PAPR signal the phases of the subcarriers are chosen pseudo-randomly. Over-the-air transmission in 865 MHz ISM band is made using directional antennas and all multicarrier waveforms have equal 5 MHz bandwidth. To evaluate the performance of harvesting device and conversion efficiency, the average voltages at the input and output of the RF-DC converter as well as at the output of the DC-DC converter with corresponding input and load impedance are measured. The experiments have shown that the employed multicarrier signals can greatly improve the performance of harvesting device during WPT under certain conditions, which are discussed in the paper.

Nowadays the RTK (Real Time Kinematic) method for positioning is used in daily life by different consumers for many purposes. Several different RTK correction techniques are used, starting from single site to network approaches. The GNSS market is filled with receivers from different manufacturers and different capabilities. In this paper we assess the stability of the reference station network transmitted RTK correction. Two different surveying class GNSS receivers in combination with four varied RTK correction techniques under diverse observation conditions are analyzed. This study has been conducted in Latvia, where state wide permanent GNSS reference station network has been maintained since year 2005.

Complex systems consist of multiple interacting parts; some of them (or even all of them) may also be systems. While performing their tasks, these parts operate with multiple data and information flows. Data are gathered, created, transferred, and analyzed. Information based on the analyzed data is assessed and taken into account during decision making. Different types of data and a large number of data flows can be considered as one of the sources of system complexity. Thus, information management, including data control, is an important aspect of complex systems development and management. According to ISO/IEC/IEEE 15288:2015, “the purpose of the Information Management Process is to generate, obtain, confirm, transform, retain, retrieve, disseminate and dispose of information, to designated stakeholders…”. Information management strategies consider the scope of information, constrains, security controls and information life cycle. This means that information management activities should be implemented starting from the level of primitive data gathering and ending with enterprise-level decision making. The articles, which have been recommended by reviewers for this issue of CSIMQ, present contributions in different aspects of information management in complex systems, namely, implementation of harmful environment monitoring and data transmitting by Internet-of-Things (IoT) systems, analysis of technological and organizational means for mitigating issues related to information security and users’ privacy that can lead to changes in corresponding systems’ processes, organization and infrastructure, as well as assessment of potential benefits that a controlled (i.e. based on the up-to-date information) change process can bring to an enterprise.