Improving the efficiency of PV low-power processing circuits by selecting an optimal inductor current of the DC/DC converter

In the context of autonomous sensors powered by small-size photovoltaic (PV) panels, this work analyses how the efficiency of DC/DC-converter-based power processing circuits can be improved by an appropriate selection of the inductor current that transfers the energy from the PV panel to a storage unit. Each component of power losses (fixed, conduction and switching losses) involved in the DC/DC converter specifically depends on the average inductor current so that there is an optimal value of this current that causes minimal losses and, hence, maximum efficiency. Such an idea has been tested experimentally using two commercial DC/DC converters whose average inductor current is adjustable. Experimental results show that the efficiency can be improved up to 12% by selecting an optimal value of that current, which is around 300-350 mA for such DC/DC converters.

Optimal latent period in a bacteriophage population model structured by infection-age

We study the lysis timing of a bacteriophage population by means of a continuously infection-age-structured population dynamics model. The features of the model are the infection process of bacteria, the death process, and the lysis process which means the replication of bacteriophage viruses inside bacteria and the destruction of them. The time till lysis (or latent period) is assumed to have an arbitrary distribution. We have carried out an optimization procedure, and we have found that the latent period corresponding to maximal fitness (i.e. maximal growth rate of the bacteriophage population) is of fixed length. We also study the dependence of the optimal latent period on the amount of susceptible bacteria and the number of virions released by a single infection. Finally, the evolutionarily stable strategy of the latent period is also determined as a fixed period taking into account that super-infections are not considered

Estimation of existing cable systems in generator-busbar unit and choice the optimal solution for its modernization

The aim of this master’s thesis is to develop an algorithm to calculate the cable network for heat and power station CHGRES. This algorithm includes important aspect which has an influence on the cable network reliability. Moreover, according to developed algorithm, the optimal solution for modernization cable system from economical and technical point of view was obtained. The conditions of existing cable lines show that replacement is necessary. Otherwise, the fault situation would happen. In this case company would loss not only money but also its prestige. As a solution, XLPE single core cables are more profitable than other types of cable considered in this work. Moreover, it is presented the dependence of value of short circuit current on number of 10/110 kV transformers connected in parallel between main grid and considered 10 kV busbar and how it affects on final decision. Furthermore, the losses of company in power (capacity) market due to fault situation are presented. These losses are commensurable with investment to replace existing cable system.

Choosing the optimal energy system for buildings and districts

The purpose of this master’s thesis was to develop a method to be used in the selection of an optimal energy system for buildings and districts. The term optimal energy system was defined as the energy system which best fulfils the requirements of the stakeholder on whose preferences the energy systems are evaluated. The most influential stakeholder in the process of selecting an energy system was considered to be the district developer. The selection method consisted of several steps: Definition of the district, calculating the energy consumption of the district and buildings within the district, defining suitable energy system alternatives for the district, definition of the comparing criteria, calculating the parameters of the comparing criteria for each energy system alternative and finally using a multi-criteria decision method to rank the alternatives. For the purposes of the selection method, the factors affecting the energy consumption of buildings and districts and technologies enabling the use of renewable energy were reviewed. The key element of the selection method was a multi-criteria decision making method, PROMETHEE II. In order to compare the energy system alternatives with the developed method, the comparing criteria were defined in the study. The criteria included costs, environmental impacts and technological and technical characteristics of the energy systems. Each criterion was given an importance, based on a questionnaire which was sent for the steering groups of two district development projects. The selection method was applied in two case study analyses. The results indicate that the selection method provides a viable and easy way to provide the decision makers alternatives and recommendations regarding the selection of an energy system. Since the comparison is carried out by changing the alternatives into numeric form, the presented selection method was found to exclude any unjustified preferences over certain energy systems alternatives which would affect the selection.

Optimal trading of wind power in the short term market

The energy reform, which is happening all over the world, is caused by the common concern of the future of the humankind in our shared planet. In order to keep the effects of the global warming inside of a certain limit, the use of fossil fuels must be reduced. The marginal costs of the renewable sources, RES are quite high, since they are new technology. In order to induce the implementation of RES to the power grid and lower the marginal costs, subsidies were developed in order to make the use of RES more profitable. From the RES perspective the current market is developed to favor conventional generation, which mainly uses fossil fuels. Intermittent generation, like wind power, is penalized in the electricity market since it is intermittent and thus diffi-cult to control. Therefore, the need of regulation and thus the regulation costs to the producer differ, depending on what kind of generation market participant owns. In this thesis it is studied if there is a way for market participant, who has wind power to use the special characteristics of electricity market Nord Pool and thus reach the gap between conventional generation and the intermittent generation only by placing bids to the market. Thus, an optimal bid is introduced, which purpose is to minimize the regulation costs and thus lower the marginal costs of wind power. In order to make real life simulations in Nord Pool, a wind power forecast model was created. The simulations were done in years 2009 and 2010 by using a real wind power data provided by Hyötytuuli, market data from Nord Pool and wind forecast data provided by Finnish Meteorological Institute. The optimal bid needs probability intervals and therefore the methodology to create probability distributions is introduced in this thesis. In the end of the thesis it is shown that the optimal bidding improves the position of wind power producer in the electricity market.

Finnish Institutional Innovation Support Policies from Russian Entrepreneurs' Perspective: Establishing Cross-Border Technology Oriented Start-Up Firm

The purpose of this thesis is to study how Russian entrepreneurs perceive Finnish institutional environment and innovation support policies provided in the country, as well as to present a practical example in form of a case study of one technology oriented start-up firm which was established in Finland by Russian entrepreneurs. The empirical research of the thesis is conducted qualitatively in two parts. First part is conducted through online questionnaire with open questions in order to review the perceptions of Russian entrepreneurs in general. Second part is based on personal interviews with case company’s founders with the focus on the process of establishing the company in Finland. In the first part of the empirical research, five Russian start-up firms were contacted, and four responses were received. All of these responses were qualified for further analysis. The findings of the first part of the research reveal that Russian entrepreneurs have rather positive attitudes towards Finnish institutional innovation support policies. However, most of the entrepreneurs stated that they are unlikely to create their presence in Finland. As an outcome of the second part of the research, the process of establishing a case company in Finland is illustrated. In order to be able to establish companies in Finland, Russian entrepreneurs who have a permanent residence outside European Economic Area (EEA) are required to apply for a permission to perform business operations in the country. In addition, the established company must engage in improving the economical stand of the country by creating new work places, raising tax revenues, develop technologies and generate innovations in the country.

Testing Futures Market Efficiency and Optimal Hedge Ratio Estimation: Evidence from Futures and Options on RTS

This study investigates futures market efficiency and optimal hedge ratio estimation. First, cointegration between spot and futures prices is studied using Johansen method, with two different model specifications. If prices are found cointegrated, restrictions on cointegrating vector and adjustment coefficients are imposed, to account for unbiasedness, weak exogeneity and prediction hypothesis. Second, optimal hedge ratios are estimated using static OLS, and time-varying DVEC and CCC models. In-sample and out-of-sample results for one, two and five period ahead are reported. The futures used in thesis are RTS index, EUR/RUB exchange rate and Brent oil, traded in Futures and options on RTS.(FORTS) For in-sample period, data points were acquired from start of trading of each futures contract, RTS index from August 2005, EUR/RUB exchange rate March 2009 and Brent oil October 2008, lasting till end of May 2011. Out-of-sample period covers start of June 2011, till end of December 2011. Our results indicate that all three asset pairs, spot and futures, are cointegrated. We found RTS index futures to be unbiased predictor of spot price, mixed evidence for exchange rate, and for Brent oil futures unbiasedness was not supported. Weak exogeneity results for all pairs indicated spot price to lead in price discovery process. Prediction hypothesis, unbiasedness and weak exogeneity of futures, was rejected for all asset pairs. Variance reduction results varied between assets, in-sample in range of 40-85 percent and out-of sample in range of 40-96 percent. Differences between models were found small, except for Brent oil in which OLS clearly dominated. Out-of-sample results indicated exceptionally high variance reduction for RTS index, approximately 95 percent.

Cultural Diversity, Social Cohesion, Religion: Core Values and Educational Policies in Four European Nations

In my doctoral thesis I evaluate strategies designed to cope with the multicultural nature of four European nations: Great Britain, The Netherlands, Sweden, and Denmark. I also analyse and clarify the question of the place of religion in present-day Europe. The empirical material analysed in the study consists of politicians’ statements and policy documents dealing with immigration policy and religious and values education in the four countries. In addition, I analyse statements issued by the Council of Europe regarding religious education, along with all cases relevant to religious education brought before the United Nations Human Rights Committee or the European Court of Human Rights. The theoretical framework is formed by the scholarly debate – among philosophers, sociologists and scholars of religion in education – concerning the question of a just society. Special emphasis is given to philosophical theories that are in favour of granting special group rights to religious minorities in the name of equal treatment. With regard to the question of the appropriate place of religion, I apply Kim Knott’s methodological model for locating religion in secular contexts, and Émile Durkheim’s theory as to the significance of religion and collective sentiments in uniting adherents or members of a group into a single moral community. The study shows that even when the positive side of immigration, as a potential force for the enrichment of the public culture, is acknowledged, there is anxiety as to the successful integration of immigrants. The premises and goals of immigration policies have also been questioned. One central problem is the incommensurability between the values upheld by Western liberal democracies and certain religious traditions, above all those of Islam. Great Britain, The Netherlands, Sweden, and Denmark have tightened control over their citizens’ ethical attitudes and want to regulate these as well. In coping with cultural diversity, the significance of education, especially religious education, plays a significant role; as future citizens, pupils are expected to internalise the society’s core values as well as gaining an understanding of different cultures and ways of life. It is also worth noting that both the Council of Europe and the European Court of Human Rights have recently expressed the view that one important goal of religious education is to enable pupils to be critical and autonomous with regard to different religions and moral positions. The study shows that religion is not seen as purely a personal matter. Religion is closely linked to individual and national identity, and religious traditions thus have a place in the public domain. It should be noted, however, that a religious tradition – more precisely, an interpretation of religious tradition – qualifies as a legitimate partner in the democratic decision-making process only if it shares similar values with Western European nations.

Iran's domestic and foreign policies

Iran has a reputation of being a problematic country. Right now, it is proceeding with its nuclear program despite the opposition of the West and neighboring countries and the massive sanctions inflicted upon it. The country is also struggling with domestic issues. Half of Iran’s population belongs to different ethnic or religious minorities. They have poor rights to express their culture in the country, which is a cause of dissatisfaction among non-Shiite and non-Persian citizens. After the Arab Spring, the situation in Iran is getting more topical than ever. In the Syrian conflict, the Shiite Iran is constantly giving support to al-Assad’s regime. These are all factors that have aggravated the already irritated relations between Iran and the West.

A simulation model of the optimal maintenance strategy: conceptual agent-based approach

In this Master’s thesis agent-based modeling has been used to analyze maintenance strategy related phenomena. The main research question that has been answered was: what does the agent-based model made for this study tell us about how different maintenance strategy decisions affect profitability of equipment owners and maintenance service providers? Thus, the main outcome of this study is an analysis of how profitability can be increased in industrial maintenance context. To answer that question, first, a literature review of maintenance strategy, agent-based modeling and maintenance modeling and optimization was conducted. This review provided the basis for making the agent-based model. Making the model followed a standard simulation modeling procedure. With the simulation results from the agent-based model the research question was answered. Specifically, the results of the modeling and this study are: (1) optimizing the point in which a machine is maintained increases profitability for the owner of the machine and also the maintainer with certain conditions; (2) time-based pricing of maintenance services leads to a zero-sum game between the parties; (3) value-based pricing of maintenance services leads to a win-win game between the parties, if the owners of the machines share a substantial amount of their value to the maintainers; and (4) error in machine condition measurement is a critical parameter to optimizing maintenance strategy, and there is real systemic value in having more accurate machine condition measurement systems.

Linear-quadratic optimal control of descriptor systems

In recent years the analysis and synthesis of (mechanical) control systems in descriptor form has been established. This general description of dynamical systems is important for many applications in mechanics and mechatronics, in electrical and electronic engineering, and in chemical engineering as well. This contribution deals with linear mechanical descriptor systems and its control design with respect to a quadratic performance criterion. Here, the notion of properness plays an important role whether the standard Riccati approach can be applied as usual or not. Properness and non-properness distinguish between the cases if the descriptor system is exclusively governed by the control input or by its higher-order time-derivatives additionally. In the unusual case of non-proper systems a quite different problem of optimal control design has to be considered. Both cases will be solved completely.

How is OpenAIRE supporting open access policies and infrastructures in Europe? A Nordic point of view!

Presentation at the Nordic Perspectives on Open Access and Open Science seminar, Helsinki, October 15, 2013