This article gives a review of modern networking technologies and standards used in the development of distributed control systems. Study of related scientific and professional literature has been performed, and basing on it a multi-level model of digital network structure in the field of small-scale autonomous combined power systems has been proposed. Necessity of integration of autonomous powering into SmartHouse systems and related distributed computing and networking issues are reflected as well. As there is a wide variety of industrial networking standards used, this review covers and groups more frequently used protocols and stacks from the view of OSI (Open Systems Interconnection) reference model and layers of industrial automation. The aim of this article is to give a reference-point in the development of distributed control systems in the field of small-scale autonomous power supply and integration of them in SmartHouse systems.

The goal of the research was to evaluate the opportunities in preparation of logistics specialists offered by Latvian universities and to formulate problem solutions. To achieve the goal, study programmes and course syllabuses offered by Latvian universities and colleges were analysed from the logistics perspective. Opportunities to acquire logistics knowledge offered in Latvia by distance, in further education and life-long learning programmes were reviewed. In the end, it was concluded that the development of logistics education in Latvia does not correspond to the speed of the development of logistics industry. Currently Latvia offers 4 Logistics study programmes, but only one study programme offers education corresponding to the professional standard – Manager of Logistics Department – as approved by the MoES. Latvia University of Agriculture currently has no logistics study programmes but different logistics subjects are included in the study programmes of 4 Faculties, therefore there are vast opportunities and it is necessary to develop the offer of logistics education, first by giving students the opportunity to choose specialisation in logistics in the Faculties in the study areas of which logistics is especially important and necessary – Faculty of Economics, Technical Faculty, Faculty of Forestry, Faculty of Food Technology, and Faculty of Agriculture.

Rising oil prices, national security concerns, the desire to increase farm incomes, and a host of new and improved technologies are propelling the European Union to set the directive for the year 2010 – each member state should achieve at least 5.75% biofuel usage of all used transport fuel. The report on the progress made in the use of renewable fuels shows that the average Member State of the EU has achieved only 52% of its target, and biofuels’ share in 2010 will not raise much above 4%. The prices of different biofuels are still not able to compete with oil based fuel prices. One of the possible ways how to solve this problem is to optimize biofuel supply chains using different methods of systems engineering. The aims of this investigation were finding out appropriate simulation tools for biofuel supply chain modelling, development of rapeseed oil supply chains for different production types, and modelling the developed supply chains. As the result of software survey, two packages were chosen – AnyLogic and ExtendSim Suite. Modelling studies showed that rapeseed oil supply chain is very sensitive, because changing just single parameters in a short scale, the actual cost price of 1 litre of oil changes considerably. Comparing the fossil diesel fuel prices with rape oil actual cost from modelling studies, the use of oil as a fuel for farm machinery seems to be profitable. Analysis of costs distribution shows that the greatest part is composed by rapeseed growing expenses.

The study was accomplished in 2010. The applied research methods are based on the analysis of the studies by other authors, industry experts, statistic data and the (unpublished) information provided by the Latvian district heating merchant “xxx”. Spearman’s rank correlation coefficient was used for evaluating data regularity. In 2020 the energy produced from renewable sources (Directive 2009/28/EC) in total energy consumption in Latvia has to reach 40%. Such an objective can be achieved by promoting the use of biomass at cogeneration (CHP) plants, the potential of which is the district heat supply system. Wood as an energy resource in its structure accounts for only 25-30%; therefore, the primary condition is the introduction of modern technology which would provide the possibility to diversify energy resources. The calculations confirm that the realised amount of thermal energy indirectly affects profit; directly it is affected by the rate of thermal energy, so the structure of use of energy in heat supply enterprises is associated with lowering the cost of (restrictive) factors - the energy cost, specific production technologies, energy efficiency. Currently, the primary condition of heating companies is to find such energy resource(s) to ensure the approved schedule of temperature and thermal load. The next determining factor is the energy price. In assessing the factors that will affect energy usage in the future, the main strategic principle of energy consumption will be linked to limiting the growth or even reducing heat tariff, by realising optimal efficiency and minimal environmental pollution during energy transmission.

Europe’s future wood demand for energy is expected to increase by 10 million to 200 million m3 in the period 2010- 2030. This will be supplied by both domestic sources (forests, industrial residues post-consumer wood waste), but also from sources outside Europe. The EU-28 predicts a near future (2020) gap between solid biomass supply and demand for renewable energy: 21.4 million tonnes of oil equivalents (MTOE). This is estimated via preliminary renewable energy action plans (NREAP’s) per country. The EU-28 expects wood pellet import will merely complete this gap of 21.4 MTOE, with more than 50 million tonnes of pellets. This implies a feedstock need of 125 million m3 of wood from forests and other sources outside the EU-28. A practical approach to include bioenergy in wood sector models should start with the input of wood pellets. Ideally, three types of bioenergy markets should be considered, in which pellets and the other major woody feedstock are included: 1. Large scale power production (the UK, Belgium, the Netherlands, all importing pellets from outside the EU-28); 2. Medium scale combined heat and power (CHP’s) including those in the forest sector (Nordic countries use pellets and chips for energy, merely imported from the EU-28); 3. Small scale residential heating (Germany, Austria and Italy, using wood pellets and logs from regional sources). We suggest starting with inclusion of medium scale CHP’s, followed by large scale power production. Small scale heating is relatively stable and should not have large impacts on future markets.

Nowadays, veganism is becoming increasingly popular, because health concerns are usually the primary reason why people turn to vegan diet. The aim of the study was to identify the supply of vegan products on the Latvian market by analysing the ingredients used in the production of the products, nutritional and energy value of vegan products. 192 vegan products made in 20 different countries and available in online stores that offer their goods on the Latvian market were analysed. The research was carried out from January to March 2020. Information on the country of origin, ingredients, nutritional and energy value of the products was taken from product labels. The majority of the vegan products in Latvian online stores come from Germany. The most important ingredient in the production in product groups such as meat substitutes and dairy alternatives is soya (Glycine max.), which provides high protein content. The vegan products could not be characterized as low in fat, as the average fat content in the various product groups ranged from 7.9±1.7 to 19.7±3.3 g 100 gE−1 of product, except beverages. The average energy values for all product groups varied between 210.7 kJ 100 mLE−1 for beverages and 1226.0 kJ 100 gE−1 for snacks. There would be a need for everyday vegan products in the Latvian market, as most of the products are snacks at the moment, and legumes should be used as ingredient in the production of new vegan products with increased nutritional value.

Potato sector is one of the competitive areas of the European Union (EU) agriculture. Although Eurostat declared that in 2015 Lithuanian share in the EU-28 harvested production was modest and composed only 0.7%, according to Food and Agriculture Organization of the United Nations (FAOSTAT), this crop remained on the list of top 10 commodities by net production value in Lithuanian agriculture. However, over the past decades the Lithuanian potato sector survived undesired transformations. The aim of this paper is to analyse the changes of the main indicators, related to the potato sector, and vertical price transmission among the chain of potatoes in Lithuania. The conducted research indicates the most important development trends of the potato sector and applies econometric techniques to investigate if there is any long-run relationship between the farm and retail prices of potatoes for the period of 2010 to 2016. Although the statistics show the shrinking production and domestic consumption of potatoes in Lithuania, the analysis of the vertical price transmission does not provide evidence of market inefficiencies. The Johansen cointegration test confirms the existence of a long-run relationship between the farm and retail prices, while the Granger causality test shows that there is a bidirectional causality between the examined series. The M-TAR model does not provide evidence of the farm and retail price asymmetry in the long run.

The article deals with the research results of the household electric energy usage trends impact on the electric power supply grid power factor. The amount of household appliances has increased tremendously during the last 20 to 30 years, substantially raising the electric energy consumption in private sector. As a serious technological development of household appliances took place, for example, LED lamps, inverters for power supply of TV sets and computers, the introduction of microcontrollers and automated systems, as well as efficiency requirements increase for the devices used in household have led to a reduced specific energy consumption per device and increased overall energy consumption. Analytic and experimental research assured that all these changes have a substantial impact on electric grid quality, particularly on the power factor value. Filed research data proved the theoretical analysis results that there is a trend from minor inductive power factor towards considerably high capacitive power factor, thus reducing power supply grid quality. This trend must be considered seriously by the electric grid operators in order to keep high quality of energy supplied to the end users.