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An agent-based hybrid intrusion detection system Full text
2011
Paulins, N., Latvia Univ. of Agriculture, Jelgava (Latvia)
Intrusion Detection Systems is defined as a component that analyses system and user operations in computer and network system to protect it from possible intrusions. Current intrusion detection technologies have several shortcomings. Applying mobile agents to intrusion detection design is step forward on better intrusion detection. Mobile-agent based distributed intrusion detection systems are very promising for the following reasons: reduction of data movement, load-balance, flexibility, fault-tolerance, detection of distributed attacks. Hybrid intrusion detection is defined by both the method used to detect attacks and the placement of the system on the network. Intrusion detection system may perform either misuse detection or anomaly detection and may be deployed as network-based or host-based system. This paper proposes to distribute classical intrusion detection model with mobile agents making an agent-based hybrid intrusion detection system. The proposed model can help detect simple intrusions in early stage and also distributed intrusions by monitoring several subjects installed on network. Main benefit from mobile agents in such system is ability to generate separate services for specific tasks and analyze unknown user patterns with several methods of artificial intelligence.
Show more [+] Less [-]In silico analysis of steady state mechanisms of metabolic networks in COBRA Toolbox and FBA-SimVis Full text
2011
Odzina, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Pentjuss, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
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.
Show more [+] Less [-]Fine-root biomass and morphology in scots pine Pinus sylvestris L. young stands Full text
2011
Bardulis, A., Latvia Univ. of Agriculture, Jelgava (Latvia);Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Jansons, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)) | Liepa, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
In the summer 2010, a study of the below-ground biomass of young (12 - and 14-year-old) Scots pine Pinus sylvestis L. stands was carried out in central Latvia. The fine-root (diameter is less than 2 mm) biomass, tips, length and volume were determined for the mineral soil layer (0 – 60 cm) by core sampling. The main objective was to determine the average fine-root biomass and morphological characteristics in different classes of young stands of Scots pines. The mean fine-root biomass was calculated for the whole stand by using below-ground biomass measurements of different components of sample trees and measurement of the tree stand. The amount of dry fine-root biomass in the soil layer was 5.3 ± 1.6 t haE-1 in the 14-year-old stand and 3.6 ± 1.5 t haE-1 in the 12-year-old stand. The study showed that the largest portion (52%) of the total fine-root biomass of 12 - and 14-year-old Scots pine stands was located at a depth of 0–10 cm, decreasing in deeper mineral soil layers. The average morphological characteristics of fine roots were higher in the older stand. Analysis of the morphology of fine roots showed that at soil depth of 0 – 10 cm the mean root length was 233 ± 44 cm, volume – 1.3 ± 0.6 cm3, value of tips – 537 ± 104 and diameter – 0.7 ± 0.1 mm per 100 cmE-3.
Show more [+] Less [-]Characterization of severe damages of spruce (Picea abies (L.) H. Karst.) stands in relation to soil properties Full text
2011
Lazdins, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Miezite, O., Latvia Univ. of Agriculture, Jelgava (Latvia) | Bardule, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Severe damages of spruce stands were found during recent years in several countries of the Baltic sea region. Characteristic indications of these damages are trees with brownish drying tops distributed across the whole compartment. During the first year only forests on drained organic soils suffer. In the second and third years, according to experiences gained in Lithuania, the damages move to other stand types. In Latvia, the first signals about the damages of spruce stands arrived from the company ''Rīgas meži'' in May, 2010. ''Rīgas meži'' found damaged stands in 2 forestries. The most of the damaged stands were on organic soils. The inspection of other forests by the State forest service identified similar damages in Southern part of Latvia as well as in other regions with considerable areas of organic soils. In August, 2010 ''Rīgas meži'' did their own inspection in Olaine and Tīreļi forestries and found out that 24% of spruce stands has characteristic signs of damages, and in 10% of stands dead or significantly damaged trees were found. Due to theses damages, about 300 ha of spruce stands were harvested in sanitary clear-felling in 2010. Spreading of spruce bud scale, Physokermes piceae (Schrnk.), is found to correlate with damages of spruce stands in Latvia and Lithuania. This pest is well known in both countries, but never before it caused any serious damages to spruce stands. In Sweden another bud scale insect (Physokermes inopinatus Danzig and Kozár) is found to be the reason for spruce damages.
Show more [+] Less [-]Radial growth of Norway spruce in the polluted western part of Latvia Full text
2011
Zalkalns, O., Latvia Univ. of Agriculture, Jelgava (Latvia)
Environmental pollution that has been one of the key issues for decades has still not lost any of its topicality. In order to study the impact of air pollution on the growth of Norway’s spruce (Picea abies (L.) Karst.), 31 sample plots were established at different distances and directions from the pollution points in the Western part of Latvia. The plots were established starting from the year 2008 summer-autumn season and finishing with the spring of 2009. The selected stands were 32 - 171 year old and of different forest site types. The selection was used in the State Forest Service database and cartographic materials. Empirical data was obtained from each of the plots which reflected the environmental effects on the trees. To ascertain the effect of air pollution on the growth of Norway spruce, the algorithm based on additional increment to volume was used. Air pollution affects eating, regardless of age and the type of growing conditions. Pollution effects are closely related to the distance from the source.
Show more [+] Less [-]Profitability of silver birch (Betula pendula Roth.) breeding in Latvia Full text
2011
Jansons, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Gailis, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Donis, J., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Economic importance of Silver birch in Latvia has been increasing in last decade, triggering scientific research, dedicated to improvement of this species, including tree breeding. Bulk of progeny trials will reach the evaluation time in next few years; therefore, decisions for further tree breeding activities have to be made. The aim of our study is to evaluate profitability of silver birch breeding, based on current situation in the year 2010 and circumstances in Latvia and assess the factors that might notably influence the result. Analysis considers all available breeding material and links between tree breeding, seed orchards and end product – forest stand, regenerated with improved plants in order to evaluate profitability of different alternatives based on differential approach. Results reveal that differential benefits from forest regeneration with selected birch material in comparison to natural regeneration, in areas with highest site indexes (Ia-II) with 3% interest rate and at least part of the stands managed in order to maximize yield of large diameter trees at age of final felling, are positive. The highest profitability can be reached if selection of best individuals is done based on clonal testing, genetic gain is maximized and combined with proper silvicultural praxis and annual planting area (utilization of seeds from selected trees) are maximized.
Show more [+] Less [-]Economic aspects of game management in Latvia Full text
2011
Baumanis, J., Latvia Univ. of Agriculture, Jelgava (Latvia) | Straupe, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Donis, J., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
At different points in the history there have been attempts to evaluate the volume and value of separate game-related goods and services in Latvia; however, so far there have been no comprehensive studies covering the role of the game management and its impact on Latvia’s economy. Such data would be necessary not only to evaluate the impact of the game management on Latvia’s economy, but also to set appropriate priorities in cases where game animals cause damage to other sectors of economy. In order to evaluate the role of the game management in the national economy, lists of the game-related goods and services have been drafted, sources of information have been identified to determine the volume and monetary value of the goods and services in the 2009/2010 hunting season, as well as a methodology has been developed to acquire the missing information. It has been determined that the total monetary value of the game-related products was 3.66 million LVL, while the game-related services accounted for 18.86 million LVL. The total contribution of the game management to Latvia’s economy in the 2009/2010 hunting season has been estimated at 22.52 million LVL. Among the game-related products the most significant product is the game meat total amount (sales and own consumption) of which has been estimated at 2.8 thousand tons, while total value accounted for 3.6 million LVL. Among the game-related services the most significant contributors are the following: sales of hunting equipment (6.7 million LVL) and game-related transportation costs (4.7 million LVL).
Show more [+] Less [-]The assessment of contribution of forest plant non-wood products in Latvia's national economy Full text
2011
Donis, J., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Straupe, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
The forests in Latvia occupy 49.9% of territory and they have significant economic, ecologic and social functions. The notion ‘forest value’ is frequently understood as the value of wood only but non-wood values are often neglected because there are methodological and practical difficulties to estimate them in monetary terms. The list of forest plant non-wood product (FPNWP) groups potentially important for Latvia was made and the significance of them in Latvia’s national economy was estimated. To obtain the information about FPNWP in Latvia (kinds, amounts, value, own-consumption) the public opinion poll was carried out. 77% of the residents of Latvia aged 18 - 74 have gathered the nature products in Latvia in 2010. The most significant FPNWP are mushrooms, wild berries of family Ericaceae - Vaccinium myrtillus L., Vaccinium vitis-idaea L., Oxycoccus palustris Pers. and birch sap. The contribution of FPNWP in the Latvia’s national economy in 2010 was 66.8 million LVL, including 8.9 million LVL for the products sold in the market or exchanged among households.
Show more [+] Less [-]Management competences assessment in small and medium-sized forest enterprises Full text
2011
Tunkele, S., Latvia Univ. of Agriculture, Jelgava (Latvia) | Marcins, J., Latvia Univ. of Agriculture, Jelgava (Latvia) | Domkins, A., Forest and Wood Products Research and Development Inst., Jelgava (Latvia)
The role of small and medium-sized enterprises (SME) in the development of economics becomes more important, as they can quickly re-orientate in the rapidly changing economic situation, and they are the main guarantee of wellbeing on the regional scale. Although these enterprises are different, still the SME in the European Union meet several similar difficulties. One of the main problems of the SME is lack of management competences that causes difficulties in ensuring efficient management of the enterprises. The aim of the research was to investigate the competences that are necessary for the employees to carry out their duties from the point of view of small and medium-sized forest enterprises (SMFE). The task of the research was to identify problems faced by the SMFE management in daily business. To get results, the qualitative interview method was used as well as, survey was carried out, and the obtained data from well-established methodology and criteria were evaluated. The research results show that the distribution at the SME is specific professional competence with 40%, social competence with 23%, methodical and individual competence with 19% and 18%. The results show that necessary management competences in SME and large enterprises are equal, but the kind of their application and topicality differ; therefore, it is essential to organize activities of professional development concerning the definite model and type of business. The professional teaching models for SMFEs should be according to enterprises management specifics, focusing on the fact that managers of SMFEs to combine the competences.
Show more [+] Less [-]Use of timber resources for development of wood processing industry Full text
2011
Krumins, J., Latvia Univ. of Agriculture, Jelgava (Latvia) | Smits, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Dagis, S., Latvia Univ. of Agriculture, Jelgava (Latvia) | Dubrovskis, D., Latvia Univ. of Agriculture, Jelgava (Latvia)
Forest industry consists of two related industries forestry and wood processing. Wood processing industry, which is a direct consumer of timber resources generated by forestry sector is eager to search for an answer about kind and amount of round wood they can count on in long term period. In Latvia for every five years State Forest Service calculates cutting volumes for the state owned forests based on models which do not guarantee safe long term income maximization. Long term cutting volumes and assortments in privately owned forests have not been analyzed very deeply. The aim of the research was to estimate the hypothetic amount of different timber resources available in the territory of Latvia for wood processing industry within next hundred years and look at geographic location of timber resources and woodworking companies. Research results showed that forests in Latvia are not being depleted and current annual cutting volumes could be increased. Geographic observation of primary wood processing companies showed that most of them are located close to large cities or near main roads of Latvia. This location makes easier round wood deliveries to factory and facilitates transportation of produced goods to an end customer. To clarify where and what profile (softwood or hardwood) production volumes should be increased, model of timber resource demand indicator was implemented.
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