By using analytical correlations derived as a result of theoretical research, a computer algorithm has been worked out for simulating the functions of the plough body and the forces exerted by soil upon the operating parts, as well as its draft resistance. These correlations allow to determine the draft resistance of the plough depending on the parameters of its body, as well as to evaluate the impact of the physical and mechanical properties of soil, such as friction upon it. The greatest influence upon the draft resistance is exerted by soil hardness, density and slip resistance along the surfaces of the operating parts. The latter is also affected by soil adhesion, which particularly manifests itself in wet clay soils at lower temperatures. It has been clarified that the friction resistance constitutes 46–62% of the total draft resistance of the plough body. The main ways of lowering the friction resistance and the total draft resistance of the plough are the introduction of a more rational design of its body having optimum parameters, decreasing the resistance of the share-mouldboard surface and the values of reactions of the supporting surfaces, as well as the application of antifriction materials and better modes of joining with tractors.

In forest harvesting process, a logging company and a forest landowner who have various goals concerning forest stands purchase value are involved. The logging company wants to maximize the profit on lower price, but forest landowner - to extract maximum income. Calculating the forest stands value prior to harvesting it is possible to achieve mutually acceptable price. This article describes question statement and primary research of prior calculated and harvested volume difference for further study of forest stands purchase value algorithm optimization. Harvested volume from feed-back data and prior calculated forest stands volume were compared to obtain the difference and understand the economical importance for optimization of harvesting sites maximal value calculation algorithm. For primary study, forest stands prior harvesting calculation model from the logging company was used. Results from prior harvesting calculations were compared with data after harvesting to achieve information about the precision of calculation model. Obtained results showed significant difference between prior calculated and harvested volumes, which in financial matter cause losses to the logging company. Compared to total harvested volume, negative cutting difference was 7% from volume, which in financial terms with annual harvesting of 1 million m**3 make loss of ~2.3 million euro.

The paper “Latvian Services Sector Development Model: Internet Solution” addresses an issue of the quality of business environment in the Latvian services sector. In the paper, there are analyzed governmentally supported information systems, data bases and e-services aiming at simplification of B2G communication process, identified their advantages and drawbacks, as well as determined potential for their further development. As a result, a model for optimization of governmental on-line tools, fostering an access to business-related information and fulfilment of administrative procedures in the services sector, has been developed. The paper provides a diversified four-layer solution, which may be progressively realized, depending on the available financial resources.

Forethought deployment of an industrial production system is a significant step towards improving economic benefit of an industrial company. The author proposes the procedure for finding an optimal specification of multirobot system, which considers it on the level of components of the robotic system. Components are grouped into mobile or stationary units of the system. A set of agents is considered as a solution for particular mission, it defines a specification of a heterogeneous multi-robot system. The paper presents the concept of the optimization procedure and describes the implementation of investment costs optimization step, which uses genetic algorithm.

Metabolic analysis is one of the research focuses of systems biology. Two aspects of metabolic networks -network topology and stoichiometry - are what current researchers are most interested in, and both studies have revealed significant information. The research of the stoichiometric matrix of metabolic network has generated a series of powerful methodologies such as flux balance analysis (FBA). For FBA different methods execution are used different software like COBRA Toolbox and FBA-SimVis. The aim of this paper is to compare and analyze functionality of these two toolboxes, metabolic network data conformation conditions, and to compare all available FBA methods comparison in calculation possibilities and visual interpretation way. FBA, when analyzing all fluxes using different options, gives results in its metabolic network flow chart, although Cobra Toolbox returns the results in the matrix in number formats. FBA-SimVis for Steady state metabolic network models analysis is provided for a small metabolic network, because making some FBA analysis there are a ten possibilities to change an unlimited count of variables, to choose or change or optimize reactions as variables. Cobra Toolbox for Steady state metabolic network models analysis is provided for greater metabolic networks with hundreds or thousands of reactions. It allows changing an unlimited count manipulating and optimizing reactions fluxes.

Theoretical and experimental investigations are carried out to estimating the impact of the plough body working width on its specific draft resistance, as well as the ploughing efficiency. By using analytical correlations derived as a result of theoretical research, a computer algorithm has been worked out for simulating the functions of the plough body and the forces exerted by soil upon the operating parts, as well as its draft resistance. Specific draft resistance of the plough body, energy consumption, as well as labour efficiency and ploughing costs depend considerably on the working width of the body. By increasing it, the energy capacity, specific fuel consumption and expenditure decrease, but labour efficiency increases.

The main parameters of the plough body that determine the ploughing efficiency are the initial and the final soil trip lifting angles on the share-mouldboard surface, the angles of its horizontal generatrix, the radius of this surface, and the working width of the body. By using analytical correlations derived as a result of theoretical research, a computer algorithm has been worked out for simulating the functions of the plough body and the forces exerted by soil upon the operating parts, as well as its draft resistance. These correlations allow to determinate the forces acting on the plough body and its draft resistance depending on the share inclination angle, as well as to evaluate its impact on the ploughing efficiency: energy, and the fuel consumption, and the quality of work. By increasing the initial lifting angle epsilon, (inclination angle of share toward furrow bottom) the draft resistance increases. For economical ploughing, the initial lifting angle of the soil strip must have a minimal value, its optimum may vary 28...32 deg. The use of bodies having optimal parameters allows obtaining good ploughing quality, reduce draft resistance by 12...20% and to raise correspondingly the efficiency, to save fuel and financial resources for ploughing.

In the paper there are described problems of sewerage system in Riga which essentially impede its normal functioning. There are analyzed operation regimes of two principal pumping stations which pump all wastewater of Riga to the purification plants (2001-2005). The main focus is on implementing different measures that would improve collection and pumping of wastewater. It is offered to build a third penstock from the Voleru chamber to the purification plants. It is suggested to separate the rainwater from the household wastewater. There are analyzed 11 different versions of pump operation. In the conclusions and recommendations the formation of the possible dangerous situation during heavy downpours is demonstrated. It is recommended to build a regulation reservoir near the purification plants which could essentially protect the Daugava from unpurified wastewater during the downpours.

Production of cereals is mostly processed by operating the machinery. Operation of machinery influences the yield, i.e. also the income on one side, but it is also one of the biggest sources of expenses from the other side. Increasing the yearly operation time and amount of work of the machinery leads to decreasing costs per unit. Increasing the yearly amount of work is limited by agrotechnical terms. The crop yield depends on the time and duration of field work, and affects the farm income. The methods and formulae to prognosticate the averageoptimum yearly operation time of farm's machinery, i.e. also farm's cereal-growing area was composed by the author, concerning biological, technical and economical factors and relations, affecting cereal production. Farm profit and profitability were used as optimization criteria.