Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

    We have a manual that explains all the features 

Current refinement(s):

Records 1 - 20 / 38

  • help
  • print

    Print search results

  • export

    Export search results

  • alert
    We will mail you new results for this query: keywords==schattingen
Check title to add to marked list
De waarde van een gedetailleerde bodemkaart van een waterwingebied
Knotters, M. - \ 2015
Stromingen : vakblad voor hydrologen 21 (2015)2. - ISSN 1382-6069 - p. 29 - 41.
water catchment - groundwater level - yields - damage - soil surveys - soil types - calculation - estimates - noord-brabant - waterwinning - grondwaterstand - opbrengsten - schade - bodemkarteringen - bodemtypen - berekening - schattingen
Boeren in waterwingebieden hebben recht op vergoeding van schade veroorzaakt door daling van de grondwaterstand als gevolg van waterwinning. Bij de berekening van de schades wordt onder meer gebruik gemaakt van bodemkaarten. De vraag die in dit artikel centraal staat is of gedetailleerde kaarten (schaal 1:25.000) opweegt tegen de baten, of dta met toepassing van de landelijke bodemkaart (schaal 1: 50.000) kan worden volstaan. Een validatiestudie is verricht voor het gebied Vierlingsbeek.
Synthese monitoring mestmarkt 2006-2012
Koeijer, T.J. de; Luesink, H.H. ; Daatselaar, C.H.G. - \ 2014
Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-technical report 18)
dierlijke meststoffen - markten - monitoring - landbouwtellingen - schattingen - aanbod - vraag - kosten - landbouw - nederland - animal manures - markets - agricultural censuses - estimates - supply - demand - costs - agriculture - netherlands
De aanvoer en afzet van dierlijke mest via de mestmarkt in Nederland zijn op verzoek van het ministerie van Economische Zaken (EZ) voor de periode 2006-2012 in beeld gebracht. Dit is gedaan op basis van analyses van de Vervoersbewijzen Dierlijke Mest (VDM’s) van RVO.nl (Rijksdienst voor Ondernemend Nederland) en op basis van modelberekeningen met MAMBO. Dit WOt-technical report geeft een synthese van de resultaten. Op basis van vergelijkbare meststromen is het aanbod op basis van de VDM’s 73 mln. kg fosfaat. Op basis van modelberekeningen is dit aanbod 74 mln. kg fosfaat. De afzet naar landbouwbedrijven vormt met 40% de belangrijkste afzetpost op de VDM’s. De overige afzetposten op de VDM’s zijn export (28%), verwerking (28%), particulieren (3%) en overige bestemmingen (1%)
Is er ruimte voor wolven in Nederland?
Potiek, A. ; Wamelink, G.W.W. ; Jochem, R. ; Langevelde, F. van - \ 2013
Vakblad Natuur Bos Landschap 100 (2013). - ISSN 1572-7610 - p. 32 - 35.
wolven - fauna - habitatfragmentatie - populatiedynamica - schattingen - predatie - inventarisaties - wolves - habitat fragmentation - population dynamics - estimates - predation - inventories
De wolf nadert Nederland. Uit een modelstudie blijkt dat er genoeg geschikt leefgebied is voor mogelijk vijftig wolven. Door de aanwezigheid van ecoducten wordt de kans op een duurzame wolvenpopulatie aanzienlijk vergroot.
Recreational fishery in the Netherlands: demographics and catch estimates in marine and fresh water
Hammen, T. van der; Graaf, M. de - \ 2013
IJmuiden : IMARES (Report / IMARES Wageningen UR C147/13) - 33
sportvissen - visserij-ecologie - actieve recreatie - vangstsamenstelling - inventarisaties - schattingen - methodologie - game fishes - fisheries ecology - active recreation - catch composition - inventories - estimates - methodology
De Nederlandse overheid heeft EU verplichtingen met betrekking tot het rapporteren van vangsten door recreatieve vissers. Het betreft gegevens over de omvang van de visserij op kabeljauw, aal, haaien en roggen. Sportvisserij Nederland was nauw betrokken bij de eerste surveys in 2010-2011. Dit rapport geeft een overzicht van de vangstschattingen van de meest gevangen zout en zoetwatersoorten uit de eerste logboek survey van 2010-2011. Daarnaast gaat het in op de methodiek hoe deze inschattingen tot stand zijn gekomen.
Rainfall variability in the Netherlands from radars, rain gauges, and disdrometers
Beek, R. van de - \ 2013
University. Promotor(en): Remko Uijlenhoet, co-promotor(en): Hidde Leijnse. - S.l. : s.n. - ISBN 9789461736437 - 128
regen - neerslag - radar - regenmeters - hydrologie - meteorologie - schattingen - schatting - meettechnieken - meetsystemen - nederland - rain - precipitation - rain gauges - hydrology - meteorology - estimates - estimation - measurement techniques - measurement systems - netherlands

Chapter 1. This thesis presents studies on the variability of precipitation in the Netherlands from datasets collected by radars, rain gauges and disdrometers. Accurate rainfall estimates are highly relevant in hydrology, meteorology and climatology as precipitation has a large impact on society. Precipitation has been studied extensively in the past, although it is impossible to describe all processes and behavior involved. This thesis attempts to add to the knowledge on precipitation. In the first chapter a short overview of rainfall variability at different scales is presented together with the most common instruments for measuring precipitation.

Chapter 2. The spatial variability of daily rainfall accumulations is studied. Ninety-day averaged semi-variograms are created based on a 30-year data set gathered by automatic stations operated by the Royal Netherlands Meteorological Institute (KNMI). This is complemented by a one-year dataset of 10 gauges within a 5 km radius around CESAR (Cabauw Experimental Site for Atmospheric Research) in the center of the Netherlands. It is shown that it is possible to derive an average semi-variogram that describes the climatology of daily precipitation for each day of the year.

Chapter 3. The study of chapter 2 is extended by investigating accumulation intervals shorter than daily scales. These are at 12, 8, 6, 4, 3, 2 and 1-hour accumulation intervals. It is shown that at shorter temporal scales the behavior of semi-variograms of precipitation still shows a clear seasonal trend. At hourly and two-hourly accumulation intervals the signal of the range becomes fairly constant during the summer due to the limited accumulation period, the frequent occurrence of convective precipitation, and measurement errors. This illustrates the lower limit of using cosine functions to describe variogram parameters. By fitting a power-law function through the different cosine parameters it is possible to describe the semi-variance of precipitation at scales between 1 and 24 hours using a limited set of equations.

Chapter 4. Different sources of error affecting rainfall estimates by weather radar are identified. By focussing on precipitation near a C-band radar some of these sources are reduced, which allows to focus on a limited set of error sources. These are radar calibration, ground clutter, wet radome attenuation and variations in rain drop size distribution. An event that caused high precipitation amounts in a band along the center of the Netherlands and more than 50~mm near the radar between the 25th and the 27th of August 2010 is studied. Without any correction and by applying a standard Marshall-Palmer Z-R relation the radar is found to underestimate by approximately 50% with respect to the rain gauge measurements. Using the sun for calibration a correction of 1 dB is applied. Clutter is corrected by subtracting a clear sky clutter map as this proves to provide better results than the standard doppler filter. Wet-radome attenuation is corrected by looking at the amount of attenuation at a known strong clutter pixel near the radar. Disdrometer data near the radar are used to derive accurate Z-R relations specific to the precipitation of the event. These corrections combined provide very promising results with a slight overestimation of the quantitative precipitation estimates (QPE) from the radar by 5 to 8%.

Chapter 5. An extensive dataset of 195 precipitation events measured by an X-band radar (SOLIDAR) is used to study precipitation at a high spatial resolution of 120 m and a high temporal resolution of 16 s. This study shows the benefit of using such high resolution X-band radars over flat terrain. The errors in the radar measurements are first assessed and corrected as well as possible by considering different techniques. These errors are calibration, ground clutter and attenuation. Finally, five strongly different precipitation events are studied in detail to illustrate the strengths and weaknesses of the X-band weather radar.

Chapter 6. The variability and possible measurement methods of precipitation have been studied. It was shown that precipitation spatial and temporal variability has a clear statistical signal by analyzing variograms for different accumulation intervals. Weather radars were also shown to be able to give good estimates of precipitation at ground level as well as detailed information on the spatial variability. Some recommendations are given to perform follow up studies. For chapters 2 & 3 it is recommended to use a larger and more detailed dataset, which also incorporates Belgian and German data. This would allow the study of anisotropy in the semi-variograms as well as extending the analysis to accumulation times shorter than 1 hour and longer than 24 hours. For chapter 4 it is recommended to study pixels located further away from the radar. While other error sources would become more pronounced it would be possible to study the applicability of the proposed corrections at longer ranges. Studying the wet-radome attenuation with several strong clutter pixels near the radar would allow the study of wind-effects on wet-radome attenuation, possibly allowing corrections using measurements of (Doppler) wind-speed and direction. Finally, in chapter 5 it is recommended to study the successor of SOLIDAR, IDRA, which is currently operational at CESAR. This radar is a polarimetric radar, allowing a more detailed study of precipitation together with the data from other instruments at this location and the C-band radar of KNMI, which is located close to this location at approximately 23 km.

De status en toekomst van iLUC in de wetenschap : van kwantificering naar preventie
Faaij, A. ; Meijl, H. van; Broens, D.F. - \ 2011
[Den Haag] : LEI Wageningen UR
biobased economy - indirecte veranderingen van landgebruik - voorspellingen - beleid - schattingen - indirect land use change - forecasts - policy - estimates
Biobrandstoffen worden als een duurzame oplossing gezien voor het opraken van fossiele brandstof. Toch is er veel debat over de omvang van indirect land use change (iLUC) door het stimuleren van bio-brandstoffen. In de wetenschap is sprake van voortschrijdend inzicht. De eerste hoge schattingen zijn door betere studies naar beneden bijgesteld. En er zijn nog steeds veel verbeteringen in gegevens en modellen mogelijk. Bovendien lijkt het iLUC-effect goeddeels voorkomen te kunnen worden met de juiste aanpassingen in landbouw en veeteelt.
Comparison of chamber and eddy covariance-based CO2 and CH4 emission estimates in a heterogeneous grass ecosystem on peat
Schrier-Uijl, A.P. ; Kroon, P.S. ; Hensen, A. ; Leffelaar, P.A. ; Berendse, F. ; Veenendaal, E.M. - \ 2010
Agricultural and Forest Meteorology 150 (2010)6. - ISSN 0168-1923 - p. 825 - 831.
methaan - kooldioxide - emissie - schattingen - eddy-covariantie - broeikasgassen - veenweiden - methane - carbon dioxide - emission - estimates - eddy covariance - greenhouse gases - peat grasslands - carbon-dioxide exchange - flux measurements - methane emission - nitrous-oxide - water-vapor - spatial variation - soil respiration - polygonal tundra - fen - systems
Fluxes of methane (CH4) and carbon dioxide (CO2) estimated by empirical models based on small-scale chamber measurements were compared to large-scale eddy covariance (EC) measurements for CH4 and to a combination of EC measurements and EC-based models for CO2. The experimental area was a flat peat meadow in the Netherlands with heterogeneous source strengths for both greenhouse gases. Two scenarios were used to assess the importance of stratifying the landscape into landscape elements before up-scaling the fluxes measured by chambers to landscape scale: one took the main landscape elements into account (field, ditch edge ditch), the other took only the field into account. Non-linear regression models were used to up-scale the chamber measurements to field emission estimates. EC CO2 respiration consisted of measured night time EC fluxes and modeled day time fluxes using the Arrhenius model. EC CH4 flux estimate was based on daily averages and the remaining data gaps were filled by linear interpolation. The EC and chamber-based estimates agreed well when the three landscape elements were taken into account with 16.5% and 13.0% difference for CO2 respiration and CH4, respectively. However, both methods differed 31.0% and 55.1% for CO2 respiration and CH4 when only field emissions were taken into account when up-scaling chamber measurements to landscape scale. This emphasizes the importance of stratifying the landscape into landscape elements. The conclusion is that small-scale chamber measurements can be used to estimate fluxes of CO2 and CH4 at landscape scale if fluxes are scaled by different landscape elements
Eddy covariance observations of CH4 and N2O : Towards more accurate emission estimates
Kroon, P. ; Hensen, A. ; Jonker, H. ; Schrier-Uijl, A.P. ; Bosveld, F. - \ 2009
methaan - distikstofmonoxide - eddy-covariantie - meteorologische waarnemingen - emissie - schattingen - methane - nitrous oxide - eddy covariance - meteorological observations - emission - estimates
Poster presentation at the Early Career Scientist Workshop, 20 – 22 August 2009, Melbourne Australia.
Toward a consistency cross-check of eddy covariance flux-based and biometric estimates of ecosystem carbon balance
Luyssaert, S. ; Reichstein, M. ; Schulze, E.D. ; Janssens, I.A. ; Law, B.E. ; Papale, D. ; Dragoni, D. ; Goulden, M.L. ; Granier, A. ; Kutch, W.L. ; Linder, S. ; Matteucci, G. ; Moors, E.J. ; Munger, J.W. ; Pilegaard, K. ; Saunders, M. ; Falge, E.M. - \ 2009
Global Biogeochemical Cycles 23 (2009). - ISSN 0886-6236 - 13
netto ecosysteem koolstofbalans - schattingen - eddy-covariantie - primaire productie - biometrie - meetsystemen - net ecosystem carbon balance - estimates - eddy covariance - primary production - biometry - measurement systems - net primary production - gross primary production - ponderosa pine forests - mixed hardwood forest - water-vapor exchange - soil co2 efflux - european forests - beech forest - chamber measurements - spatial variability
Quantification of an ecosystem's carbon balance and its components is pivotal for understanding both ecosystem functioning and global cycling. Several methods are being applied in parallel to estimate the different components of the CO2 balance. However, different methods are subject to different sources of error. Therefore, it is necessary that site level component estimates are cross-checked against each other before being reported. Here we present a two-step approach for testing the accuracy and consistency of eddy covariance–based gross primary production (GPP) and ecosystem respiration (Re) estimates with biometric measurements of net primary production (NPP), autotrophic (Ra) and heterotrophic (Rh) respiration. The test starts with closing the CO2 balance to account for reasonable errors in each of the component fluxes. Failure to do so within the constraints will classify the flux estimates on the site level as inconsistent. If the CO2 balance can be closed, the test continues by comparing the closed site level Ra/GPP with the Rh/GPP ratio. The consistency of these ratios is then judged against expert knowledge. Flux estimates of sites that pass both steps are considered consistent. An inconsistent ratio is not necessarily incorrect but provides a signal for careful data screening that may require further analysis to identify the possible biological reasons of the unexpected ratios. We reviewed the literature and found 16 sites, out of a total of 529 research forest sites, that met the data requirements for the consistency test. Thirteen of these sites passed both steps of the consistency cross-check. Subsequently, flux ratios (NPP/GPP, Rh/NPP, Rh/Re, and Re/GPP) were calculated for the consistent sites. Similar ratios were observed at sites which lacked information to check consistency, indicating that the flux data that are currently used for validating models and testing ecological hypotheses are largely consistent across a wide range of site productivities. Confidence in the output of flux networks could be further enhanced if the required fluxes are independently estimated at all sites for multiple years and harmonized methods are used
Effect of temporal resolution on N2O emission inventories in Dutch fen meadows
Nol, L. ; Heuvelink, G.B.M. ; Vries, W. de; Kros, J. ; Moors, E.J. ; Verburg, P.H. - \ 2009
Global Biogeochemical Cycles 23 (2009). - ISSN 0886-6236 - 15
distikstofmonoxide - broeikasgassen - emissie - schattingen - laagveengronden - veenweiden - regen - nederland - nitrous oxide - greenhouse gases - emission - estimates - fen soils - peat grasslands - rain - netherlands - nitrous-oxide emissions - fertilizer application rate - greenhouse-gas emissions - pasture simulation-model - pnet-n-dndc - managed grasslands - field validation - forest soils - nitric-oxide - peat soil
Most countries use a 1-year-resolution emission factor approach (Tier 1 or 2) to estimate terrestrial N2O emissions as part of their national greenhouse gas inventory. Little attention has so far been paid to the effect of the temporal resolution of the approach (e.g., day, season, and year) on N2O emission estimates. The effect of lumping temporal variation can be very large because of daily or seasonal variations of processes causing N2O emissions. Therefore, we compared annual N2O emissions from a model with daily time steps (DNDC) with those of a model with annual time steps (INITIATOR). Emissions were simulated for two intensively managed grassland plots in the Dutch fen meadow landscape. Annual N2O emissions from the investigated grasslands were sensitive to rainfall distribution within the year, especially to summer rainfall. We recommend that Tier 2 N2O emission estimates for intensively managed grasslands on peat soils in the temperate climate zone are adjusted for relative summer rainfall
Zijn biologische boeren minder risicomijdend dan gangbare boeren?
Gardebroek, C. - \ 2008
Stator, periodiek van VVS 9 (2008)4. - ISSN 1567-3383 - p. 9 - 13.
biologische landbouw - bedrijfssystemen - risico - bayesiaanse theorie - schattingen - risicoanalyse - organic farming - farming systems - risk - bayesian theory - estimates - risk analysis
Het toepassen van biologische landbouwmethodes is voor individuele boeren in een aantal opzichten risicovoller dan het gebruik van gangbare productietechnieken. Dit suggereert dat biologische boeren meer bereid zijn risico's te accepteren dan hun gangbare collega's. Om dit te onderzoeken zijn met behulp van Bayesiaanse schattingstechnieken en panelgegevens individuele risicocoëfficiënten geschat voor biologische en gangbare boeren.
Discard sampling of plaice (Pleuronectes platessa) and cod (Gadus morhua) in the North Sea by the Dutch demersal fleet from 2004 to 2006
Aarts, G.M. ; Helmond, A.T.M. van - \ 2007
IJmuiden : IMARES (Report / Wageningen IMARES C120/07) - 42
schattingen - gegevens verzamelen - tendensen - vistuig - demersale visserij - visstand - discards - boomkorvisserij - estimates - data collection - trends - fishing gear - demersal fisheries - fish stocks - beam trawling
Since 2002, Wageningen IMARES samples discards of the Dutch demersal (beamtrawl) fishery following the EC Data Collection Regulations (DCR) 1543/2000 and 1639/2001. In response to concerns about quality issues of these discard data, the Dutch Fish Product Board together with the Dutch fishing industry started its own plaice discards program in 2004. Samples of plaice and cod discards and landings are taken by fishermen on about 20 demersal vessels. Previous analysis of the Product Board’s dataset provided evidence for clear trends in time, spatial patterns, and differences between gears and individual vessels. Furthermore, it was pointed out that the IMARES program estimates higher discard percentages for plaice than the self-sampling program.
Integration of three strucutally different stock assessment models in a Bayesian framework
Kraak, S.B.M. ; Bogaards, H. ; Borges, L. ; Machiels, M.A.M. ; Keeken, O.A. van - \ 2007
IJmuiden : IMARES (Report / Wageningen IMARES C043/07) - 7
vissen - beoordeling - schattingen - bayesiaanse theorie - voorspellen - modellen - visstand - fishes - assessment - estimates - bayesian theory - forecasting - models - fish stocks
Bayesian statistics provide a method for expressing uncertainty of an unknown parameter value probabilistically (www.bayesian.org). Bayesian methods have been widely used in biological sciences, and recently in fisheries science applied to stock assessment. In our previous studies on Bayesian analysis for the F-project, we have explored three structurally different stock assessment models in a Bayesian framework. These models are not only different with respect to their data needs, they also represent different hypotheses about the stock dynamics.
Waterbird Population Estimates - Fourth Edition
Delany, S. ; Scott, D. ; Helmink, A.T.F. - \ 2006
Wageningen : Wetlands International - ISBN 9058820319 - 239
watervogels - vogels - schattingen - populatiebiologie - waterfowl - birds - estimates - population biology
Kwantificering van beschikbare biomassa voor bio-energie uit Staatsbosbeheerterreinen
Tolkamp, G.W. ; Berg, C.A. van den; Nabuurs, G.J.M.M. ; Olsthoorn, A.F.M. - \ 2006
Wageningen : Alterra (Alterra-rapport 1380) - 46
biomassa - energievoorraden - biomassa productie - nationale bossen - kwantitatieve analyse - schattingen - nederland - biomass - energy resources - biomass production - national forests - quantitative analysis - estimates - netherlands
Deze eerste schatting van de jaarlijkse potentiële en fysiek oogstbare hoeveelheid biomassa die door Staatsbosbeheer geleverd kan worden aan bio-energie centrales in Nederland bedraagt jaarlijks bijna 1 miljoen ton droge stof. Van dit aanzienlijke potentieel bedraagt zestig procent de bijgroei van bossen en de overige veertig procent is de fysiek oogstbare bijgroei in heide, gras en rietlanden. Bij bossen wordt rekening gehouden met reguliere houtoogst, die niet beschikbaar zal komen voor bio-energiecentrales. Bij handhaving van de huidige houtafzetkanalen zou SBB in het totaal bijna 750.000 ton droge stof biomassa (afkomstig van bossen, heide, gras en rietlanden) beschikbaar kunnen stellen. Dit zou ruwweg overeen komen met een vermeden emissie fossiele brandstof van 1.6 miljoen ton CO2. Het rapport draagt bij vooral in de discussie bij tot een verdieping van de problematiek rondom biomassa productie voor bio-energie
Ontwikkeling Automatisch Glasaaltelapparaat en Hevel
Storbeck, F. ; Burggraaf, D. ; Bult, T.P. - \ 2006
IJmuiden : IMARES (Rapport / IMARES C065/06) - 16
palingen - monitoring - motivatie - schattingen - visbestand - eels - motivation - estimates - fishery resources
De glasaalintrek is sterk achteruitgegaan. Dit heeft tot gevolg dat zeer lage aantallen glasalen gevangen worden met het kruisnet gedurende de jaarlijks terugkerende Wageningen IMARES glasaalmonitoring. Deze ontwikkeling creëert een aantal monitoringsproblemen: 1. De schattingsvariatie neemt toe door de lage vangsten en de vele 0-waarnemingen. Hierdoor is het moeilijk te bepalen of de glasaalintrek de laatste jaren verder afneemt, toeneemt, of gelijk blijft. 2. De vele 0-vangsten gaan ten koste van de motivatie van medewerkers Als oplossing is een ontwikkelingsproject gestart rond een apparaat dat glasaal volautomatisch herkent en telt als onderdeel van een hevelsysteem.
The determination of biomass reference points for North Sea plaice: The influence of assumptions about discards, wieght, maturity and stock-recruitment relationships
Kraak, S.B.M. ; Bolle, L.J. ; Rijnsdorp, A.D. - \ 2005
IJmuiden : RIVO (Report / RIVO-Netherlands Institute for Fisheries Research no. C056/05) - 26
visserij - visserijbeheer - visbestand - schol - bepaling - schattingen - referentienormen - modellen - noordzee - visstand - ecologische beoordeling - discards - fisheries - fishery management - fishery resources - plaice - determination - estimates - reference standards - models - north sea - fish stocks - ecological assessment
Noordzee schol wordt net als vele andere visbestanden beheerd met betrekking tot referentiepunten. Dit rapport behandelt de biologische basis voor de referentiepunten en evalueert of de huidige referentiepunten wetenschappelijk verantwoord zijn
Quality manual part II: International data collection and raising procedures
Keeken, O.A. van; Bolle, L.J. ; Verver, S.W. - \ 2005
IJmuiden : RIVO (Report / RIVO-Netherlands Institute for Fisheries Research no. C042/05) - 16
kwaliteitscontroles - kwaliteit - schattingen - rapporten - internationale samenwerking - visstand - quality controls - quality - estimates - reports - international cooperation - fish stocks
Products A19 to A21 form the quality manual within working package F1 of the F project. The quality manual describes the collection of the data used in the assessments and the raising procedures in two separate reports. The first report describes the collection and raising of the national data by RIVO. This second report describes the international raising procedures and contains three sections: a general section, a section on international compilation of data and a section on the stock assessment procedure.
Precision of the catch-at-age estimates from the Dutch market sampling programme
Kraak, S.B.M. ; Pastoors, M.A. - \ 2004
IJmuiden : RIVO (RIVO report no. C044/04) - 40
visserij - visbestand - soleidae - schol - bemonsteren - schattingen - modellen - visserij-ecologie - visstand - fisheries - fishery resources - plaice - sampling - estimates - models - fisheries ecology - fish stocks
In dit rapport wordt een analyse gepresenteerd van de onzekerheid in de invoergegevens van de vangst per leeftijdsgroep van schol en tong en wordt de invloed besproken van deze onzekerheid op de toestandsbeoordeling
Prijsprojecties voor de pluimveesector
Cotteleer, G. ; Kornelis, M. ; Bolhuis, J. - \ 2004
Den Haag : LEI (Rapport / LEI : Domein 8, Modellen en data ) - ISBN 905242909X - 81
agrarische economie - pluimvee - pluimveevlees - eieren - modellen - schattingen - schatting - projecties - voorspellingen - prijzen - nederland - agricultural economics - poultry - poultry meat - eggs - models - estimates - estimation - projections - forecasts - prices - netherlands
Doel van dit onderzoek is het maken van prijsprojecties voor de pluimveesector met een zo klein mogelijke projectiefout. De centrale onderzoeksvraag is: 'Kunnen we de projectiefout van prijsvariabelen in de pluimveesector verkleinen door additionele informatie op te ne-men in ons model?' We beantwoorden deze vraag door de projectieresultaten van relatief eenvoudige modellen te vergelijken met varianten waarin meer additionele informatie, bij-voorbeeld over de samenhang tussen verschillende soorten prijsvariabelen, wordt gebruikt
Check title to add to marked list
<< previous | next >>

Show 20 50 100 records per page

 
Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.