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3523 Uppsatser om Frequency inverter control - Sida 18 av 235

Trafikstyrning med variabel trafikutrustning : en behovsanalys för Vägverket Region Stockholm

When traffic in large cities increases, it becomes more vulnerable to disturbances such as accidents, stalled vehicles or construction; therefore, traffic jams are more likely to occur. For better control of the traffic at a disturbance the Swedish National Road Administration (SNRA) has traffic equipment which can be controlled from a command centre. This traffic equipment consists of gates and signs with variable messages. This report will discuss the system used for traffic control in Stockholm. It will present proposals designed to improve it.

Påverkan på energianvändning och termisk komfort vid reglerinstabilitet

The purpose of the study is to investigate the possible effects of an unstable ventilation system and its influence on energy use and thermal comfort. The report also explores how qualified personal working with HVAC view and handles system control.In order to meet the requirements in energy efficiency and a comfortable indoor climate control regulation is a prerequisite. With optimized increased complexity of the climate systems, it becomes more challenging to control the system and the risk of unstable control increases. No previous studies about what affect an unstable system can have on energy use and thermal comfort have been found.The report is based on several tests were the controlling variable has been increased until the system becomes unstable. Two different types of unstable systems have been investigated.

Predicerar organisationsrättvisa och work locus of control hälsa hos kollektivanställda män och kvinnor

Ett högt ohälsotal i arbetslivet innebär stora kostnader för samhället, arbetsgivare och även för de anställda. Forskningen inom detta område har flyttat fokus från att studera ohälsa till att istället studera hälsa och vilka faktorer som befrämjar hälsa i arbetslivet, de så kallade friskfaktorerna. Föreliggande studies övergripande syfte var att studera om upplevelsen av organisationsrättvisa och personlighets¬faktorn work locus of control predicerar upplevd hälsa hos kollektivanställda män och kvinnor. Studien genomfördes utifrån ett kvantitativt perspektiv med 103 deltagare som besvarade en enkät. Svarsfrekvensen var 22,5 % och resultatet visade att work locus of control predicerar upplevd hälsa för männen och procedural rättvisa predicerar upplevd hälsa för kvinnorna.

Automatisk bedömning av reglerkretsarsprestanda

In this thesis, a computer program that in a simple way can calculate the performance of control loops at the refinery Preemraff Lysekil has been created. The computer program has been adapted to the environment at Preemraff Lysekil. Theories for evaluation has been studied in aspect of reliability and of automatic implementation. The evaluation has been carried out from data collected directly from control loops at the refinery and from simulated control loops with implemented errors. Among the studied methods are Harris index and Stattin´s oscillation index.

Biological control of powdery mildew in greenhouse produced cucumber : an evaluation of two microbiological control agents

Powdery mildew is a serious problem in both field and greenhouse cucumber production and can cause serious infection and radically reduced yields. Today, powdery mildew is the main disease in greenhouse produced cucumber. Disease control should preferably be both efficient and environmentally friendly, which is not easy to achieve at all times. Alternatives to chemical control of powdery mildews are biological control, physical control, non-fungicide control and cultivation of resistant or tolerant varieties. Biological control can be described as the suppression of damaging activities inflicted of a harmful organism by one or more other organisms, which are called antagonists or natural enemies. In Sweden, there are currently no registered biological control products available to control cucumber powdery mildew. The aim of this study was to investigate the effect of two biological control products in order to evaluate their ability to prevent or reduce powdery mildew infection to an acceptable level in greenhouse produced cucumber. In the experiments, different application regimes were also studied.

Vasakronan: Det bästa av två världar

Mergers and acquisitions are common phenomenon in today´s society in order to increase shareholder value. Two years ago a fusion of Sweden´s two largest companies in the industry of real estate took place and even though three out of four mergers and acquisitions financially fail this certain case turned out highly successful. The aim of this thesis is to examine how the organizational structure and the management control have been designed and characterized the organizational performance and furthermore what are the success factors of the integration. By studying an acquisition and its potential effects on organizational structure and management control parallel to a model that describes the best practice guidelines for managers to successfully deliver value from their acquisitions, it can be shown that an acquisition has direct effects both on the acquirer and the acquired company and thus the new organizational structure. The main results, thus, is that through active leadership, increased specialization, and more decentralized and thus efficient management control a new organization has emerged consisting of the best features of two separate worlds..

Gemensam struktur för den kommunala ekonomistyrningen

Municipalities must establish budget annually but they are free to decide how the governance should be designed, this can lead to lack of consistency and measurability within and between municipalities. The purpose of this thesis was to present a proposal for a unified and more measurable financial structure of a municipality where this was lacking. In our theory we describe the issues of traditional management control and we introduce an alternative control with non-financial ratios included, called the Balanced Scorecard. In the empirical data it is investigated how the governance of a municipality could be designed, according to the respondents. In the analysis the information gathered to reach the answers to what are considered to be useful governance in municipality, are examined. In the conclusion, we design Balanced Scorecards with both financial and non-financial ratios to the councils of the municipality..

A comparison of transporters? paddle use when unloading pigs at slaughter

Today, pigs are moved on farm, between farms, between countries and to abattoirs. This movement of live pigs requires handling practices that are designed for the purpose. The objective of this study was to research the use of paddle in moving pigs, to investigate if there were different methods of paddle practice, explore the time efficiency of different kinds of paddle use and if there were any time variations in methods that varied in intensity of touch. This study was done on two Swedish abattoirs for a total of five weeks. A total of 22 transporters working at two different abattoirs where studied during unloading of pigs at the abattoirs.

How do you measure culture? -A case study of result control within the Gothenburg Opera

Problem The culture sector is characterized by qualitative goals which raise questions such as how do you measure culture and what is ?good? culture? Both the goals and the measurements tend to result in subjective judgments, which according to the theory make result control inefficient. Yet, result control is frequently used in the culture sector; which leads up to our research question: What characterizes the problems of result control in the culture sector?Purpose The aim of this study is to make a survey of how the Gothenburg Opera works with result control and follow-up. By defining how it tackles the different problems, which could arise with result control in a non-profit organisation, we aim to map how the problems regarding result control are characterized in the Gothenburg Opera.

Kontroll i fastighetsbranschen. En kvalitativ enfallsstudie om kvinnliga och manliga chefers upplevelser av kontroll p? arbetsplatsen

This essay aims to examine managers experiences of control at the workplace within the property sector, and how these experiences differ between female and male managers. This study is a qualitative single case study that intends to offer a deeper understanding of a unique case and uses an abductive method approach. The essay is based on two main theories, Foucault?s (2003) theory of control and the gender system of Hirdman (1988, 2001) and is supplemented by previous studies of the modern workplace. The study is based on eighteen semi-structured interviews that aims to capture the participants personal experiences regarding control at the modern workplace, and the norms, surveillance, hierarchies, and self-discipline that make up this control.

Relationen mellan cyklister och fotgängare vid Södra Älvstranden, Göteborg En utvärdering av trafiken på cykelstråket Älvsborgsbron - Centrum

This paper describes a method for wireless energy transfer via near-field electromagnetic inductionthat is inexpensive, simple and can be applied to almost any type of system, regardless of size andenergy demands.The method uses a primary unit consisting of an oscillator, amplifier and inductive coil thattransfers energy to a secondary unit consisting of a coil, rectifier and voltage regulator. Two typesof oscillators and several amplifier designs were realized and evaluated together with a multitudeof flat coils of both monofilar and bifilar type.The results show that it is important to use an oscillator whose frequency is dependent on theinductance of the connected transmission coil, such as the Colpitts oscillator. This is preferable toan oscillator with a preset frequency, such as a Schmitt-trigger oscillator..

Probiotika som prevention mot urogenitala sjukdomar

About 10 % of the adult women population in Sweden are treated annually for urinary tract infections. The increasing bacterial resistance towards antibiotics is classified by WHO (World Health Organization) and ECDC (European Centre for Disease Prevention and Control) as one of the greatest treats for human health in a global perspective. To find alternatives scientists are studying the possibility to use probiotics to reduce the frequency of recurring urinary tract infections. This literature study examines five randomized double blinded placebo controlled studies where different strains of Lactobacillus have been used as a prophylactic to women suffering from recurrent urinary tract infections and bacterial vaginosis. Overall the studies do not display enough promising results to recommend the use of probiotics as a prophylax or cure..

Intern kontroll och riskhantering

The accounting scandals that have attracted attention in recent years have led to internal control becoming a more central part of business activity. Doubts about what firms actually do have increased, all caused by the attention of accounting scandals. To counter this, frameworks and laws evolved and gained a significant role in the organization and its surroundings. The aim of the present study is to find out how four companies in the Kristianstad region are working to ensure its internal control and how they work to minimize risk and reduce uncertainty. We have used a qualitative method and interviewed a person in a senior position in each company.

Optimering av informationsinsamlingvid prototyptillverkning

This report discusses a method to detect divers in harbour environments usingpassive acoustic detection. The goal was to achieve as high detection as possiblewithout having too high false alarm rate. A short execution time was also desirable.By using the characteristic of an inhalation a band-pass filter was applied to the signalto improve the signal to noise ratio. After the filtering an energy estimation of thesignal was made. This energy estimation was later used in a frequency analysis, whichcould tell us if there were enough energy in the frequencies that correspond to adivers breathing frequency.

Styrelsens användning av styrmedel -en jämförelse mellan entreprenöriella och icke-entreprenöriella företag

Management control systems are a popular area of research and a lot of new research has been done over the past years. This development has been looking into new situations and circumstances, and interdisciplinary studies are being made to further understand the connection between different fields of study. A new field of study that has grown significantly over the past few years is the connection between management control systems and entrepreneurship. Leading researchers have proposed a number of questions for further research and one of them is the board of directors? use of management control systems in entrepreneurial firms.The purpose of this study was to examine the differences and similarities in the board of directors? use of management control systems between entrepreneurial and non-entrepreneurial firms.The study was conducted as a deductive qualitative study through interviews with respondents from entrepreneurial and non-entrepreneurial firms.

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