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Browsing by Subject "herkkyysanalyysi"

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  • Kontortamännyn mahdollisuudet metsätaloudessa 
    Laitinen, Juha-Matti (2009)
    Tässä työssä kontortamännyn mahdollisuuksia metsätaloudessa tarkastellaan puuntuotannon kannattavuuden ja teollisen käytön sekä toimintaympäristön rajoiteiden: ympäristön, yhteiskunnan ja metsänhoidon näkökulmista. Kontortamännyn kasvatuksen kannattavuutta tarkastellaan vertaamalla sitä männyn kasvatuksen kannattavuuteen. Tarkastelu tehdään käyttämällä nettonykyarvolaskentaa. Lisäksi nettonykyarvolaskennan parametreille suoritetaan herkkyysanalyysi, jotta kontortamännyn kasvatuksen kannattavuuteen eniten vaikuttavat tekijät voidaan tunnistaa. Aiheesta tekee käytännöllisesti merkittävän kontortamännyn parempi tuottavuus suhteessa mäntyyn. Tämä vaikuttaa metsätalouden kannattavuuteen nostamalla hakkuukertymiä ja lyhentämällä kiertoaikaa. Työssä käytetyn aineiston ja simulointimenetelmän perusteella lasketut nettonykyarvot kontortamäntyskenaarioille olivat merkittävästi korkeammat kuin vastaaville mäntyskenaarioille lasketut nettonykyarvot, mikä kertoo kontortamännyn hyvästä kannattavuudesta metsänkasvatuksessa. Tuloksia tulkitessa tulee ottaa huomioon simulointimenetelmän rajoitteet sekä aineiston edustavuus. Suurimmiksi toimintaympäristöstä johtuviksi rajoitteiksi todettiin varauksellinen suhtautuminen vieraisiin puulajeihin, sertifioinnin rajoitteet sekä patologiset ja entomologiset riskit. Metsänhoidollisten tekijöiden ei todettu rajoittavan kontortamännyn käyttöönottoa. Merkittävin kysymys, mikä kontortamännyn käyttöönottoon laajassa mittakaavassa liittyy, on että kompensoiko parantunut puuntuotanto ja metsätalouden kannattavuus toimintaympäristön riskit ja rajoitteet.
  • Maatalousyritysten excel-perusteinen maksuvalmiussuunnittelu 
    Mannila, Sami (2020)
    It is common for farmers to have momentary problems with liquidity. This is because of long cycle of capital. Most of the production costs needs to be bought before selling any products. In agriculture production of products may last even over one year. Target of this research was to develop excel-based tool for liquidity budgeting. Excel was chosen because it is a common program and many farmers may have high threshold to buy programs that are made for liquidity budgeting. The Excel-tool was used for studying liquidity of dairy farms with sensitivity analysis. Excel-tool was filled with information from base material. Base material was from ProAgria. Base material was divided to four different sizes. Size classification was made by number of dairy cows. According to the study, dairy farms need more cash assets than Finnish listed companies in order to cope with production outages and significant changes in product prices. According to the study, dairy farms are really dependent on milk prices. Best liquidity was with group that had least dairy cows. This is because they had more field relative to dairy cows and least of dept.
  • Optimal harvesting of Tectona grandis plantation stands in Costa Rica 
    Malmström, Miika (2013)
    This thesis studies the economically optimal timing of thinnings and final harvest on Costa Rican Tectona grandis plantations. Consequently this thesis studies the profitability of the plantations and makes a comparison to previous studies. Optimization is based on programming with AMPL with Knitro optimizing software. The objective function used is the Faustmann formula. Different rates of interest are used. The ecological functions used for the modeling were obtained from previous studies by Pérez and Kanninen (2005a). The economic data such as planting and thinning costs and log prices were obtained from a T. grandis plantation specialist. The results of the study show that the optimal harvesting regime in T. grandis plantations differs from what is suggested in literature. The main findings are that the optimal rotation length is shorter and both timing and intensity of the thinnings vary depending on the rate of interest used. In addition the maximized bare land values under optimal management regimes are notably higher than bare land values under previously suggested management regimes. The management regime is highly sensitive to the rate of interest used. The management regime is less sensitive to the changes in price than expected. This thesis suggests that the initial density of 816 ha-1 trees results into higher bare land values than 1111 ha-1 trees . However, the difference is minor and possible increase in silvicultural costs is not considered. In addition a simple test is carried out to see the possible effects on heartwood proportion growth to the optimal management regime. The shortcomings and possibilities to improve the model are discussed. It is noted that the price data for T. grandis is not coherent, and that the ecological model could be improved in order to increase its accuracy.
  • Pohjaveden numeeriset laskentamallit ja niiden epävarmuustarkastelu kalliotunnelien pohjavesivaikutusarvioinnissa 
    Rahikkala, Sonja (2022)
    The construction of the Savio railway tunnel caused an unexpectedly large decrease in the groundwater heads in part of the observation points in the vicinity of the railway tunnel after the completion of the tunnel construction work. The study aimed to investigate the ability of the groundwater model to forecast such groundwater drawdown caused by a railway tunnel in the urban areas of East Hakkila, Kaskela and Hakunila. The uncertainty of the groundwater model and its sensitivity to certain parameters were studied and analyzed. The groundwater model was built using the GMS (Groundwater Modeling System) numerical groundwater modeling program. For the groundwater flow model, the bedrock mesh was built in Leapfrog Geo - program based on gravimetric measurements and rotary drilling. The groundwater model was calibrated manually and automatically to correspond to the groundwater heads measured in the area. The circumstances after the construction of the railway tunnel were then simulated. The model-calculated groundwater heads were compared to the observed groundwater heads and the observed tunnel leakage. Sensitivity analysis was performed for the horizontal conductivity parameters and recharge parameters of the model. The groundwater model before the construction of the tunnel mimicked the measured groundwater heads and flow directions in the study area. The simulation of the time after the construction of the tunnel caused groundwater drawdown of 0-16 meters at 0-730 meters from the railway tunnel. In the simulation of the time after tunnel construction, the groundwater heads calculated by the model differed by 0,01-24 meters from measured groundwater heads. According to the results of the sensitivity analysis, the model was most sensitive to changes in the horizontal conductivity of the upper bedrock layer and granite. The recharge parameters and soil layer had a marginal impact on the groundwater model. The uncertainty of the model was affected by the few measurement points in relation to the size of the area and the absence of field measurements of the hydraulic conductivity of the parameters. To reduce the uncertainty, the model should be calibrated based on the measured conductivity values of the bedrock. Despite the uncertainty, computational models give indications of the direction of change and are important tools in questions related to nature and the built environment.
  • Pohjaveden numeeriset laskentamallit ja niiden epävarmuustarkastelu kalliotunnelien pohjavesivaikutusarvioinnissa 
    Rahikkala, Sonja (2022)
    The construction of the Savio railway tunnel caused an unexpectedly large decrease in the groundwater heads in part of the observation points in the vicinity of the railway tunnel after the completion of the tunnel construction work. The study aimed to investigate the ability of the groundwater model to forecast such groundwater drawdown caused by a railway tunnel in the urban areas of East Hakkila, Kaskela and Hakunila. The uncertainty of the groundwater model and its sensitivity to certain parameters were studied and analyzed. The groundwater model was built using the GMS (Groundwater Modeling System) numerical groundwater modeling program. For the groundwater flow model, the bedrock mesh was built in Leapfrog Geo - program based on gravimetric measurements and rotary drilling. The groundwater model was calibrated manually and automatically to correspond to the groundwater heads measured in the area. The circumstances after the construction of the railway tunnel were then simulated. The model-calculated groundwater heads were compared to the observed groundwater heads and the observed tunnel leakage. Sensitivity analysis was performed for the horizontal conductivity parameters and recharge parameters of the model. The groundwater model before the construction of the tunnel mimicked the measured groundwater heads and flow directions in the study area. The simulation of the time after the construction of the tunnel caused groundwater drawdown of 0-16 meters at 0-730 meters from the railway tunnel. In the simulation of the time after tunnel construction, the groundwater heads calculated by the model differed by 0,01-24 meters from measured groundwater heads. According to the results of the sensitivity analysis, the model was most sensitive to changes in the horizontal conductivity of the upper bedrock layer and granite. The recharge parameters and soil layer had a marginal impact on the groundwater model. The uncertainty of the model was affected by the few measurement points in relation to the size of the area and the absence of field measurements of the hydraulic conductivity of the parameters. To reduce the uncertainty, the model should be calibrated based on the measured conductivity values of the bedrock. Despite the uncertainty, computational models give indications of the direction of change and are important tools in questions related to nature and the built environment.

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