2957 research outputs found
Sort by
Data Value Chain in Platform Business Models
Get PDFBuilding on a unified definition and the main attributes that have been identified for platform business models, this paper aims to devise a unified data value chain and shed a new light on the value creation process within platform business models. To meet the main aim of the paper, the following research question is addressed: "How do platform business models create, deliver and capture value through their business model configurations?". Through an integrative literature review, this paper confirmed that data is the major asset in value creation through platform business models. Furthermore, this paper has devised a unified data value chain that encom-passes sequential forms of digital data such as raw data, pre-processed data, processed data, patterns and smart data, gaining value via numerous processes throughout the data value chain. It was highlighted that interlinked processes throughout the data value chain transformed raw data into the most valuable form of data, knowledge.O
Using UAV to Identify the Optimal Vegetation Index for Yield Prediction of Oil Seed Rape (Brassica napus L.) at the Flowering Stage
Get PDFSuitability of the vegetation indices of normalized difference vegetation index (NDVI), blue normalized difference vegetation index (BNDVI), and normalized difference yellowness index (NDYI) obtained by means of UAV at the flowering stage of oil seed rape for the prediction of seed yield and usability of these vegetation indices in the identification of anomalies in the condition of the flowering growth were verified based on the regression analysis. Correlation analysis was performed to find the degree of yield dependence on the values of NDVI, BNDVI, and NDYI indices, which revealed a strong, significant linear positive dependence of seed yield on BNDVI (R = 0.98) and NDYI (R = 0.95). The level of correlation between the NDVI index and the seed yield was weaker (R = 0.70) than the others. Regression analysis was performed for a closer determination of the functional dependence of NDVI, BNDVI, and NDYI indices and the yield of seeds. Coefficients of determination in the linear regression model of NDVI, BNDVI, and NDYI indices reached the following values: R2 = 0.48 (NDVI), R2 = 0.95 (BNDVI), and R2 = 0.90 (NDYI). Thus, it was shown that increased density of yellow flowers decreased the relationship between NDVI and crop yield. The NDVI index is not appropriate for assessing growth conditions and prediction of yields at the flowering stage of oil seed rape. High accuracy of yield prediction was achieved with the use of BNDVI and NDYI. The performed analysis of NDVI, BNDVI, and NDYI demonstrated that particularly the BNDVI and NDYI indices can be used to identify problems in the development of oil seed rape growth at the stage of flowering, for their precise localization, and hence to targeted and effective remedial measures in line with the principles of precision agriculture.O
Characterization of Curing and Bonding of Wood with Adhesive Mixtures of Liquefied Wood and Hexamethylenediamine
Get PDFVarious crosslinking agents can be added to the formulations of natural-based adhesives for wood bonding in order to achieve better durability and higher strength of the formed joints. In the present study, the effect of hex-amethylenediamine (HMDA) addition on the performance of liquefied wood (LW) adhesive for wood bonding is investigated. Differential scanning calorimetry showed the improved thermal stability and crosslinking of the LW adhesive with HMDA. The intensified presence of amide linkages (C-N bonds) was found in LW+HMDA with attenuated total reflection Fourier transform infrared spectroscopy. Analysis of the bonded joints using an auto-mated bonding evaluation system showed that a higher press temperature resulted in stronger bonds for both types of adhesives. Moreover, the addition of HMDA to LW adhesive improved the bond strength of the joints and accelerated the crosslinking of the adhesive. However, with a tensile shear strength of (6.76 +/- 2.16) N x mm(-2) (for LW) and (6.89 +/- 2.10) N x mm(-2) (for LW+HMDA), both adhesives were found to be unsuitable for interior non-structural use. In addition, the acidity of LW resulted in relatively high wood failure (70%) in the adhesive joints tested. Improved crosslinking of LW with HMDA was reflected in improved resistance of LW+HMDA adhesive joints to water degradation. In conclusion, HMDA is a promising additive for improving the adhesive performance of LW adhesives.O
Environmental Effects among Differently Located and Fertile Sites on Forest Basal-Area Increment in Temperate Zone
Get PDFEnvironmental properties differently influence the growth of forest tree species. The antagonistic effects of variable environmental properties classify the forest response according to various tree compositions among different sites. The division of the forest response was assessed in 52 stands arranged into 26 types of 13 site management populations (MPs) in 5 areas in the Czech Republic territory. The assessment was performed using time-series multiple regressions of basal-area increment from pure immature stands of Norway spruce (Picea abies), Scots pine (Pinus sylvestris), oaks (Quercus sp.), ash (Fraxinus excelsior) and willows (Salix sp.) dependent on the interpolated average temperatures, annual precipitation, atmospheric concentrations of SO2, NOx and O3 and soil properties over the period 1971-2008 at p < 0.05. Site MPs differentiated the forest response to a greater extent than tree species. The response of the forests was significantly distributed by means of the montane, upland and waterlogged sites. The multiple determination index (r2) GREATER-THAN OR EQUAL TO 0.6 indicated an adaptable tree increment but an interval of r2 between 0.80-0.92 implied forest sensitivity to variability in environmental properties on non-waterlogged sites. The index r2 < 0.6 suggested a fluctuating forest increment that reflects environmental variability inconsistently. The fluctuating increment most affected the spruce and pine stands grown from upland to submontane locations. Montane spruce stands, as well as rock pines, appeared to be one of the most sensitive ones to environmental change. Floodplain forests seemed as adaptable to variable environmental properties.O
Properties of Plywood Panels Composed of Thermally Densified and Non-Densified Alder and Birch Veneers
Get PDFUkrainian companies mainly use birch in the manufacture of plywood, but species, such as black alder, are not yet widely used in the manufacture of plywood due to their poorer properties. It is well known that thermal compression is often used to improve the properties of solid wood. Good lay-up schemes of veneer can maximize the advantages and minimize the disadvantages of these wood species, and generally improve the utility value of the plywood. This research aimed to develop plywood panels with two wood species and two types of veneer treatments in order to evaluate the influences of different lay-up schemes on the properties of the plywood. Five-layer plywood panels were formed with 16 different lay-up schemes using birch (Betula verrucosa Ehrh.) (B) and black alder (Alnus glutinosa L.) (A) veneers, which were non-densified (N) and thermally densified (D). The different lay-up schemes were used to identify opportunities to improve the mechanical and physical properties of the plywood by replacing the birch veneer in the plywood structure with an alternative alder veneer. The veneer sheets were thermally densified in a laboratory hot press at a temperature of 180 oC and pressure of 2 MPa for 3 min. The conducted study showed that the bending strength, modulus of elasticity and shear strength of mixed-species plywood (BD-AN-AN-AN-BD) increased by up to 31.5%, 34.4% and 16.8%, respectively, in comparison to those properties of alder plywood from non-densified veneer (AN-AN-AN-AN-AN), by positioning alder non-densified veneers in the core layers and birch densified veneers in the outer layers. Moreover, the surface roughness of plywood panels with outer layers of birch veneer was lower than that of panels with outer layers of alder veneer. It was shown that non-treated alder veneer, despite exhibiting somewhat lower strength properties than birch veneer, could be successfully used with proper lay-up schemes in the veneer-based products industry.O
Soil Microbial Communities and Enzyme Activities after Long-Term Application of Inorganic and Organic Fertilizers at Different Depths of the Soil Profile
Get PDFFertilization is a key factor for sustaining productivity in agroecosystems. A long-term experiment in cambisol following periodical application of several types of fertilization has been running at the experimental site since 1954. In this study, we determined the impact of applied inorganic and/or organic fertilizers on the activity of soil enzymes and on the structure of microorganisms at depths of 0-30 cm and 30-60 cm. Single-factor comparison showed that use of inorganic and/or organic fertilizer had an insignificant e_ect on the activities of soil enzymes (at depths 0-30 cm and 30-60 cm) and also on the structure of microbial communities at both depths studied. Only soil respirations exhibited stimulation by combined fertilization. The results, irrespective of sampling depth (0-60 cm), showed that application of combined organic and inorganic fertilization stimulated the activity of glucosidases and use of inorganic fertilizer inhibited the activity of arylsulphatases. Respirations were stimulated by application of organic fertilizer and combined fertilization. Nevertheless, principal component analyses, which calculate with multidimensional data, revealed di_erences in samples treated by sole mineral fertilizer compared to other variants, especially in the lower layer. In general, our results indicate that use of combined fertilization may improve biological characteristics in deeper parts of soil profile and possibly increase biological activity in agroecosystems.O
Combined Fertilizers Versus Dolomitic Limestone: A Comparative Study from a Forest Habitat with Norway Spruce
Get PDFThe research paper with character of case study deals with the influence of amelioration on soil as well as the Norway spruce nutrition and growth, with the focus on dolomitic limestone and combined fertilizer applications. The study was performed in the 7-year-old forest stand (Nízký Jeseník Mountains, Czech Republic, 100% Norway spruce, podzol, mor humus form, slightly undulated slope, 770m a.s.l.). The soil properties (soil reaction, nutrient status, C/N ratio and cation exchange capacity), the plant nutrition, the plant biomass production and the health status were measured. Neither the expected significant increase in pH due to liming in the root zone nor the increase in calcium and magnesium in the soil was confirmed. In the dolomitic limestone treatment, the highest hydrolytic acidity reaching 260 mmol+/kg, the worst development of assimilatory organs, the growth and health status of individuals were ascertained one year after the usage. The application of combined fertilizers resulted in the highest response in the needle biomass production (0.35 g/100 needles compared to less than 0.30 g/100 needles in the dolomitic limestone treatment), in the potassium and phosphorus nutrition status (suboptimal 4-4.5% of potassium in dolomitic limestone and the control treatment compared to optimal 5.5-7.5% in the combined fertilizers treatments) and simultaneously to the optimization of the health status. Specifically, in forest stands, the effect of dolomitic limestone is rather overestimated and furthermore, chemical amelioration requires the detailed knowledge of the forest site.O
Evaluation of semen parameters from Fleckvieh-Simmental bulls and the influence of age and season of collection
Get PDFThe aim of this paper was to evaluate semen parameters from Czech Fleckvieh (dual-purpose breed) bulls used in artificial insemination in the Fleckvieh population. The ejaculate was collected from bulls only once a week, which is not usual. Respectively, the effects of age and season of collection on semen parameters were tested. The average volume of ejaculate by Fleckvieh bulls was 8.72 mL, which is higher than results in studies of bulls which were collected usually more than once a week. The average total motility was 72.82 % and progressive motility was 67.99 %. Sperm concentration reached on average 1254.10x106 mLMINUS SIGN 1. The total motility of spermatozoa after thawing was 40.88 %. A significant influence of age was observed on ejaculate volume, total and progressive motility, and total motility after thawing (P<0.05). The season of collection had a significant influence on the volume of ejaculate, total motility, progressive motility, concentration of spermatozoa, and total count of spermatozoa (P<0.01).O
Examining the Stand Level CO2 Fluxes of Spring Forest Geophytes
Get PDFSpring forest ephemerals often create homogeneous patches in the understory; however, our knowledge about their stand level characteristics is deficient. Our aims were to examine, parallel to their phenology, the stand level Net Ecosystem CO2 Exchange (NEE) and evapotranspiration (ET) fluxes as well as the dependence of NEE on leaf area (LA), air temperature (Tair) and light (PPFD) in three spring forest geophytes that are widespread in Europe. Furthermore, we compared the leaf and stand level net photosynthesis. The methods used included open chamber measurements with an infrared gas analyser in permanent plots on a weekly basis. The results showed that the stand levels of all three species proved to be carbon sinks from the beginning of the vegetation period until the end of it or until the last phase of fruit formation. The largest amount of carbon sink was observed at the peak of blooming. A positive linear correlation was measured between NEE and PPFD as well as between NEE and LA, while a negative linear regression was measured between NEE and Tair. The remarkable carbon uptake capacity indicates the non-negligible role of geophyte vegetation in the carbon flux of temperate forests. In addition, the research provided new proof about the role of stand level operation, stability and regulation.O
Consumers' perceptions of health and factors influencing fulfilment of the need for healthcare in eu countries
Get PDFThe paper deals with subjective perceptions of health by individuals. The research aimed at understanding socioeconomic and demographic factors influencing the fulfilment of healthcare needs and at finding out categories of factors that lead to the highest chances of meeting the need in consumer segments formed according to perceptions of their health status. The analyses were based on the EU-SILC database of primary data on the income situation and living conditions of households. In 2017, the database included extra questions on health. The method of cluster analysis was employed. As a result, three clusters of individuals representing EU countries formed depending on the perceived state of health - the authors named the clusters 'optimistic', 'neutral', and 'pessimistic'. For each segment, the binary logistic regression was applied to determine categories of factors leading to the highest probability of meeting the healthcare need. The greatest influence over the fulfilment of the need for healthcare has been confirmed for the factor "Sector of economic activity", followed by the type of economic activity. Some differences were revealed between segments. For example in the third segment, i.e., respondents who rated worst their health, a strong influence of education has been identified. The highest chances of meeting the need for health care are achieved in the first segment by executives, but in the second and the third segment by individuals active in education. On the other hand, craftsmen and workers have the lowest chances. In all segments, the influence of household composition was confirmed, with single households and single-parent households reporting lower chances of meeting their healthcare needs. Respondents who did not feel their healthcare need was met mostly said it was due to financial reasons, long waiting times, or fear of medical treatment.O