11 resultados para 2008-2011 food price spikes
em Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland
Resumo:
This report summarizes the work done by a consortium consisting of Lappeenranta University of Technology, Aalto University and VTT Technical Research Centre of Finland in the New Type Nuclear Reactors (NETNUC) project during 2008–2011. The project was part of the Sustainable Energy (SusEn) research programme of the Academy of Finland. A wide range of generation IV nuclear technologies were studied during the project and the research consisted of multiple tasks. This report contains short articles summarizing the results of the individual tasks. In addition, the publications produced and the persons involved in the project are listed in the appendices.
Resumo:
Starttiraha ja yrittäjyys Uudellamaalla on vuoden 2012 laadittu tutkimus, jonka toteuttamisesta vastasi Uudenmaan elinkeino-, liikenne- ja ympäristökeskuksen Yhteiset toiminnot -yksikkö. Tutkimuksen päämääränä oli tarkastella vuosien 2008-2011 aikana Uudellamaalla aloittaneiden yrittäjien kokemuksia starttirahajärjestelmästä sekä kartoittaa heidän yritystoimintansa tilannetta vuonna 2012. Lisäksi tutkimuksessa selvitettiin, millaisiksi starttirahaa saaneet yrittäjät arvioivat alueen työ- ja elinkeinosta saadut yrittäjäpalvelut. Tutkimus toteutettiin sähköpostikyselynä myönteisen starttirahapäätöksen Uudenmaan alueen työ- ja elinkeinotoimistoista vuosien 2008-2011 aikana saaneille henkilöille. Kyselyyn vastasi 728 starttiraha saanutta entistä ja nykyistä yrittäjää. Kyselyaineiston lisäksi tutkimuksessa käytettiin hyödyksi Työ- ja elinkeinoministeriön Työnvälitystilaston tarjoamaa tilastotietoa vuosien 2006-2011 ajalta. Tulokset osoittivat, että starttiraha koettiin erittäin hyödylliseksi järjestelmäksi yritystoiminnan alkuvaiheessa. Vastaajista 90 % koki starttirahan olleen erittäin tarpeellinen toimeentulonturva. Se oli mahdollistanut yrittäjille mm. hieman laajemman taloudellisen liikku-mavaran yritystoiminnan ensikuukausina. Starttirahan saamisella koettiin olleen myös suuri henkinen merkitys. Myönteinen starttiraha-päätös nähtiin yhteiskunnan symboliseksi tavaksi antaa hyväksyntä yritystoiminnalle. Järjestelmän heikkouksiksi kuitenkin laskettiin tuen alhainen määrä, suhteellisen lyhyt kesto sekä hakuprosessin raskaus. Kyselyyn vastanneet starttirahayrittäjät arvioivat yritystensä tulevaisuudennäkymät suhteellisen positiivisiksi. Yrityksensä liikevaihdon kasvua lähitulevaisuudessa ennakoi 62 % vastaajista. Starttirahayritykset eivät kuitenkaan olleet kovin suuria työllistäjiä. Usein yritys työllisti ainoastaan yrittäjän itsensä. TE-toimistojen henkilökunta ja heidän starttirahaan liittyvät palvelunsa saivat tutkimuksessa erittäin hyvän arvosanan. Vastaajat arvioivat jokaisen eritellyn asiakokonaisuuden arvosanan TE-toimistojen osalta joko kiitettäväksi tai hyväksi.
Resumo:
Electricity spot prices have always been a demanding data set for time series analysis, mostly because of the non-storability of electricity. This feature, making electric power unlike the other commodities, causes outstanding price spikes. Moreover, the last several years in financial world seem to show that ’spiky’ behaviour of time series is no longer an exception, but rather a regular phenomenon. The purpose of this paper is to seek patterns and relations within electricity price outliers and verify how they affect the overall statistics of the data. For the study techniques like classical Box-Jenkins approach, series DFT smoothing and GARCH models are used. The results obtained for two geographically different price series show that patterns in outliers’ occurrence are not straightforward. Additionally, there seems to be no rule that would predict the appearance of a spike from volatility, while the reverse effect is quite prominent. It is concluded that spikes cannot be predicted based only on the price series; probably some geographical and meteorological variables need to be included in modeling.
Resumo:
For decades researchers have been trying to build models that would help understand price performance in financial markets and, therefore, to be able to forecast future prices. However, any econometric approaches have notoriously failed in predicting extreme events in markets. At the end of 20th century, market specialists started to admit that the reasons for economy meltdowns may originate as much in rational actions of traders as in human psychology. The latter forces have been described as trading biases, also known as animal spirits. This study aims at expressing in mathematical form some of the basic trading biases as well as the idea of market momentum and, therefore, reconstructing the dynamics of prices in financial markets. It is proposed through a novel family of models originating in population and fluid dynamics, applied to an electricity spot price time series. The main goal of this work is to investigate via numerical solutions how well theequations succeed in reproducing the real market time series properties, especially those that seemingly contradict standard assumptions of neoclassical economic theory, in particular the Efficient Market Hypothesis. The results show that the proposed model is able to generate price realizations that closely reproduce the behaviour and statistics of the original electricity spot price. That is achieved in all price levels, from small and medium-range variations to price spikes. The latter were generated from price dynamics and market momentum, without superimposing jump processes in the model. In the light of the presented results, it seems that the latest assumptions about human psychology and market momentum ruling market dynamics may be true. Therefore, other commodity markets should be analyzed with this model as well.
Resumo:
Electricity price forecasting has become an important area of research in the aftermath of the worldwide deregulation of the power industry that launched competitive electricity markets now embracing all market participants including generation and retail companies, transmission network providers, and market managers. Based on the needs of the market, a variety of approaches forecasting day-ahead electricity prices have been proposed over the last decades. However, most of the existing approaches are reasonably effective for normal range prices but disregard price spike events, which are caused by a number of complex factors and occur during periods of market stress. In the early research, price spikes were truncated before application of the forecasting model to reduce the influence of such observations on the estimation of the model parameters; otherwise, a very large forecast error would be generated on price spike occasions. Electricity price spikes, however, are significant for energy market participants to stay competitive in a market. Accurate price spike forecasting is important for generation companies to strategically bid into the market and to optimally manage their assets; for retailer companies, since they cannot pass the spikes onto final customers, and finally, for market managers to provide better management and planning for the energy market. This doctoral thesis aims at deriving a methodology able to accurately predict not only the day-ahead electricity prices within the normal range but also the price spikes. The Finnish day-ahead energy market of Nord Pool Spot is selected as the case market, and its structure is studied in detail. It is almost universally agreed in the forecasting literature that no single method is best in every situation. Since the real-world problems are often complex in nature, no single model is able to capture different patterns equally well. Therefore, a hybrid methodology that enhances the modeling capabilities appears to be a possibly productive strategy for practical use when electricity prices are predicted. The price forecasting methodology is proposed through a hybrid model applied to the price forecasting in the Finnish day-ahead energy market. The iterative search procedure employed within the methodology is developed to tune the model parameters and select the optimal input set of the explanatory variables. The numerical studies show that the proposed methodology has more accurate behavior than all other examined methods most recently applied to case studies of energy markets in different countries. The obtained results can be considered as providing extensive and useful information for participants of the day-ahead energy market, who have limited and uncertain information for price prediction to set up an optimal short-term operation portfolio. Although the focus of this work is primarily on the Finnish price area of Nord Pool Spot, given the result of this work, it is very likely that the same methodology will give good results when forecasting the prices on energy markets of other countries.
Resumo:
Chemical-looping combustion (CLC) is a novel combustion technology with inherent separation of the greenhouse gas CO2. The technique typically employs a dual fluidized bed system where a metal oxide is used as a solid oxygen carrier that transfers the oxygen from combustion air to the fuel. The oxygen carrier is looping between the air reactor, where it is oxidized by the air, and the fuel reactor, where it is reduced by the fuel. Hence, air is not mixed with the fuel, and outgoing CO2 does not become diluted by the nitrogen, which gives a possibility to collect the CO2 from the flue gases after the water vapor is condensed. CLC is being proposed as a promising and energy efficient carbon capture technology, since it can achieve both an increase in power station efficiency simultaneously with low energy penalty from the carbon capture. The outcome of a comprehensive literature study concerning the current status of CLC development is presented in this thesis. Also, a steady state model of the CLC process, based on the conservation equations of mass and energy, was developed. The model was used to determine the process conditions and to calculate the reactor dimensions of a 100 MWth CLC system with bunsenite (NiO) as oxygen carrier and methane (CH4) as fuel. This study has been made in Oxygen Carriers and Their Industrial Applications research project (2008 – 2011), funded by the Tekes – Functional Material program. I would like to acknowledge Tekes and participating companies for funding and all project partners for good and comfortable cooperation.
Resumo:
Tämä kandidaatintyö liittyy Lappeenrannan teknillisessä yliopistossa 2008-2011 käynnissä olevaan Tekesin tutkimushankkeeseen ”Alumiiniveneen hitsauksen automatisointi”. Tällä hetkellä Suomessa pienemmät veneenrungot hitsataan käsin, sillä robottihitsauksessa tulee ongelmaksi hitsin luokse pääseminen, etenkin kokoonpanohitsauksessa. Automaatiohitsauksessa myös tarvitaan huomattavasti tarkemmat railotoleranssit kuin käsinhitsauksessa, koska hitsausrobotti on sokea hitsausliitosten poikkeamille. Hitsauksen automatisoinnilla pyritään nostamaan nykyistä tuotantokapasiteettia ja yleisesti parantamaan alumiinirakenteiden hitsien laatua. Työn tarkoituksena on tutkia erilaisia railonvalmistusmenetelmiä alumiinin hitsausta varten, sekä casena pohtia railonvalmistusmenetelmien soveltuvuutta robotisoituun MIG-hitsaukseen alumiinisessa veneenrungossa. Työssä pohditaan hitsauksen, sekä robotisoidun hitsauksen railonvalmistukseen soveltuvia leikkausmenetelmiä, railonvalmistusta yleisesti, toleransseja, alumiinin työstöominaisuuksia, sekä leikkausmenetelmien taloudellisuutta. Työssä käsitellään railovaatimuksia mm. MIG-, TIG-, plasma-, sekä laserhitsaukselle.
Resumo:
Tämän tutkimuksen tarkoituksena on tutkia perusopetuksen rehtoreiden käsityksiä siitä, miten rehtori johtaa opettajakuntaansa ja koulua oppivan organisaation suuntaan. Tutkimus etsii vastauksia koulun kehittämisen ja pedagogisen hyvinvoinnin yhtymäkohtiin. Tutkimus on perusopetuksen rehtoreiden keskuudessa Salossa tehty tapaustutkimus, jonka tiedonkeruu ajoittui vuosille 2008–2011. Tutkimuksen ensimmäinen osa oli tulevaisuusverstas (n=14). Verstaan pohjalta tutkimukselle syntyi teoreettinen viitekehys ja aineiston keräämistä jatkettiin puolistrukturoidulla teemahaastattelulla (n=14). Tulokset toimitettiin nettiportaaliin, jossa haastatteluun osallistuneilla rehtoreilla oli mahdollisuus kommentoida analyysia. Kun teoriaohjaava analyysi oli saatettu käsitekarttojen muotoon, rehtorit osallistuivat palauteverstaaseen, missä ryhmäkeskustelujen avulla validoitiin tutkimustuloksia. Tutkimuksen taustafilosofia on fenomenologia: se tutkii rehtoreiden havaintoihin ja kokemuksiin perustuvia käsityksiä tutkimusalueesta. Rehtoreiden käsitykset oman koulunsa osaamisen tasosta perustuivat kokemusperäiseen tunteeseen, joka syntyy oman joukon tuntemisesta. Rehtorit eivät pystyneet järjestelmällisesti selvittämään, millaista osaamista ja osaamisen tarvetta koulussa on. Omaan toimintatapaansa rehtorit liittivät tunneälyn, jonka avulla he kokivat voimaannuttavansa opettajakuntaansa opettajien itsensä ja koko kouluorganisaation kehittämisen suuntaan. Tutkimukseen osallistuneilla kouluilla ei ollut kirjoitettuja kehittämis-suunnitelmia ja -tavoitteita, mutta rehtorit sanoivat sellaisten olevan selvillä heillä itsellään. Rehtorit totesivat, että opettajien täydennyskouluttautuminen on lähinnä opettajien omista motivaatioista lähtöisin eikä se yksittäisenä tapahtumana kehitä koulun kollektiivista osaamista ja oppivan organisaation syntymistä. Varsinaisia toimenpiteitä oppivan organisaation kehittämiseksi ei tehty. Rehtorit kuitenkin katsoivat pedagogisen hyvinvoinnin kokemuksen kehittyvän koulussa. Rehtoreiden käsitysten mukaan esimiehen tuki sekä osaamisen kokemus vahvistavat hallinnan tunnetta, joka toimii hyvinvoinnin kokemuksen lähtökohtana. Pedagogisen hyvinvoinnin kokemukseen liittyy turvallinen ja avoin toimintakulttuuri. Rehtorit kuvailivat toimivansa eri opettajien kanssa eri tavoin. Rehtoreiden mukaan osaaminen, hallinnan tunne ja pedagoginen hyvinvointi muodostavat kolmikannan, mikä noudattaa myös aiempia DCS-teoriaan pohjautuvia tutkimustuloksia hallinnan tunteen ja hyvinvoinnin yhteydestä.
Stochastic particle models: mean reversion and burgers dynamics. An application to commodity markets
Resumo:
The aim of this study is to propose a stochastic model for commodity markets linked with the Burgers equation from fluid dynamics. We construct a stochastic particles method for commodity markets, in which particles represent market participants. A discontinuity in the model is included through an interacting kernel equal to the Heaviside function and its link with the Burgers equation is given. The Burgers equation and the connection of this model with stochastic differential equations are also studied. Further, based on the law of large numbers, we prove the convergence, for large N, of a system of stochastic differential equations describing the evolution of the prices of N traders to a deterministic partial differential equation of Burgers type. Numerical experiments highlight the success of the new proposal in modeling some commodity markets, and this is confirmed by the ability of the model to reproduce price spikes when their effects occur in a sufficiently long period of time.
Resumo:
Food systems in Sub-Saharan Africa have been rapidly transforming during the recent decades with diverse outcomes on human development and environment. This study explores the food system change in rural villages in eastern Tanzania where subsistence agriculture has traditionally been the main source of livelihood. The focus is on the salient changes in the spatial dimensions and structural composition of the food system in the context of economic liberalization that has taken place after the end of the socialist ujamaa era in the mid-1980s. In addition, the linkages of the changes are examined in relation to food security, socio-economic situation, livelihoods, and local environment. The approach of the study is geographical, but also involves various multi-disciplinary elements, particularly from development studies. The research methods included thematic and questionnaire interviews, participatory tools, and the analysis of land use/ cover data and official documents. Several earlier studies that were made in the area during the late 1970s and 1980s provided an important reference base. The study shows that subsistence farming has lost its dominant role in food provisioning due to the declining productivity of land, livestock losses, and the increasing shift of labour to non-farm sectors. Also rapid population growth has added to the pressure on land and other natural resources. Despite the increasing need for money for buying marketed foods and other necessities, the nutritional situation shows improvement and severe malnutrition has diminished. However, the long-term sustainability of this transformation raises concerns. Firstly, the food security situation continues to be fragile and prone to shocks such as adverse climatic conditions, crop failures and price hikes. Secondly, the commodification of the food system and livelihoods in general is linked to rapid environmental degradation in the area, particularly the loss of soil fertility and deforestation. The situation calls for efforts that take more determined and holistic approaches towards sustainable development of the rural food system with particular focus on the role and viability of small-scale farming.