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Limitation of distribution system voltage by decentralised load controlScott, Nigel Clive January 2000 (has links)
No description available.
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Gruppchefens förmågaLundgren, Jens January 2009 (has links)
<p>The Swedish armed forces has for many years educated squad leaders by letting them start their training two and a half months before the soldiers start their training. 2007, this system was used for the last time. I went trough this system myself in 2005 and had a positive experience and when I did my internship I experienced a slight difference in the attitude of the squad leader. I talked with my colleges at the company and they had felt the same. This essay will try to analyse if the squad leaders has lost any of there ability and if so, what could be the cause? To analyze the ability of the squad leader in this essay it will first analyze their ability through the <em>Direct leadership</em> theory, which is the theory that is presently used in the Swedish armed forces. The method used is hypothesis. The hypothesis is as follows; Squad leaders have lowered their ability since the cancellation of advance training. Then the organization was analysed to see if the organization changed the conditions for the squad leader. What was realized was that the ambition of the organization has been lowered and this can be a reason why squad leaders are experienced as if they lowered their ability. Then the squad leaders was analysed to see if they even lowered their ability at all by analyzing what their ability was before they started their education. Finally six officers were interviewed about their experience with the squad leaders both before having the advance education and after. The conclusions are that there hasn’t been a significant decrease in the squad leaders’ capacity that can be measured but that the loss of advance education has decreased their confidence and it’s more difficult for them become natural leaders of their groups. Another conclusion is that the actual training for the squad leaders’ has decreased considerably.</p> / <p>Försvarsmakten har under ett flertal år använt sig av förstegsutbildning vid utbildandet av gruppchefer. Inför utbildningsåret 2008 avskaffades detta system och en generell uppfattning bland officerare är att gruppcheferna inte har haft möjlighet att nå samma färdighet i deras befattning efter denna förändring.</p><p>Denna uppsats avser att utreda om det har blivit en förändring av förmågan hos gruppchefen samt identifiera eventuella faktorer som kan ha påverkat gruppchefens utbildning. Uppsatsen beskriver först de grundläggande ledarskapsteorierna för att använda dessa som ett mätinstrument för gruppchefens förmåga. Därefter jämförs olika resultat från utbildningsåren 03-04, 04-05 och 08 för att se om gruppchefens förmåga har förändrats dessutom intervjuas officerare om deras uppfattning av gruppchefen efter förstegsutbildningens avskaffande. Slutsatserna som dras är att avskaffandet av förstegsutbildningens avskaffande inte har påverkat förmåga mätbart men att gruppchefens självförtroende har sänkts. Gruppchefen har också fått kortare utbildning vilket innebär att deras utbildningsståndpunkt blir lägre än gruppchefer med förstegsutbildningen.</p>
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Gruppchefens förmågaLundgren, Jens January 2009 (has links)
The Swedish armed forces has for many years educated squad leaders by letting them start their training two and a half months before the soldiers start their training. 2007, this system was used for the last time. I went trough this system myself in 2005 and had a positive experience and when I did my internship I experienced a slight difference in the attitude of the squad leader. I talked with my colleges at the company and they had felt the same. This essay will try to analyse if the squad leaders has lost any of there ability and if so, what could be the cause? To analyze the ability of the squad leader in this essay it will first analyze their ability through the Direct leadership theory, which is the theory that is presently used in the Swedish armed forces. The method used is hypothesis. The hypothesis is as follows; Squad leaders have lowered their ability since the cancellation of advance training. Then the organization was analysed to see if the organization changed the conditions for the squad leader. What was realized was that the ambition of the organization has been lowered and this can be a reason why squad leaders are experienced as if they lowered their ability. Then the squad leaders was analysed to see if they even lowered their ability at all by analyzing what their ability was before they started their education. Finally six officers were interviewed about their experience with the squad leaders both before having the advance education and after. The conclusions are that there hasn’t been a significant decrease in the squad leaders’ capacity that can be measured but that the loss of advance education has decreased their confidence and it’s more difficult for them become natural leaders of their groups. Another conclusion is that the actual training for the squad leaders’ has decreased considerably. / Försvarsmakten har under ett flertal år använt sig av förstegsutbildning vid utbildandet av gruppchefer. Inför utbildningsåret 2008 avskaffades detta system och en generell uppfattning bland officerare är att gruppcheferna inte har haft möjlighet att nå samma färdighet i deras befattning efter denna förändring. Denna uppsats avser att utreda om det har blivit en förändring av förmågan hos gruppchefen samt identifiera eventuella faktorer som kan ha påverkat gruppchefens utbildning. Uppsatsen beskriver först de grundläggande ledarskapsteorierna för att använda dessa som ett mätinstrument för gruppchefens förmåga. Därefter jämförs olika resultat från utbildningsåren 03-04, 04-05 och 08 för att se om gruppchefens förmåga har förändrats dessutom intervjuas officerare om deras uppfattning av gruppchefen efter förstegsutbildningens avskaffande. Slutsatserna som dras är att avskaffandet av förstegsutbildningens avskaffande inte har påverkat förmåga mätbart men att gruppchefens självförtroende har sänkts. Gruppchefen har också fått kortare utbildning vilket innebär att deras utbildningsståndpunkt blir lägre än gruppchefer med förstegsutbildningen.
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Cardiac MRI: Improved Assessment of Left Ventricular Function, Wall Motion, and ViabilityKrishnamurthy, Ramkumar 16 September 2013 (has links)
Heart failure is the clinical syndrome accompanying the inability of the heart to maintain a cardiac output required to meet the metabolic requirements and accommodate venous return, and is one of the leading causes of mortality in United States. Accurate imaging of the heart and its failure is important for successful patient management and treatment. Multiple cardiac imaging modalities provide complementary information about the heart – LV function and wall motion, anatomy, myocardial viability and ischemia. In many instances, it is necessary for a patient to undergo multiple imaging sessions to obtain diagnostic clinical information with confidence. It would be beneficial to the individual and the health care system if a single imaging modality could yield reliable clinical information about the heart, leading to a reduced cost, anxiety and an increased diagnostic confidence. This thesis proposes methods that would make cardiac MRI perform an improved assessment of LV function, wall motion, and viability, such that cardiac MRI is taken one step closer to being a single stop solution for imaging of heart.
Conventional cardiac MR imaging is performed at a temporal resolution of around 40 ms per cardiac phase. While the global left ventricular (LV) function can be reliably established at this temporal resolution, functional metrics characterizing transient function like peak filling and ejection rates are not accurately assessed. A high temporal resolution is necessary to characterize such transient LV function and wall motion mechanics. This thesis proposes methods to acquire cine-images of the heart at a higher temporal resolution (~ 6 ms) and algorithms to acquire the LV volume across all cardiac phases that would yield functional metrics characterizing LV function and wall motion mechanics. The validation of these algorithms was performed on human subjects.
Cardiac MR imaging is the current gold standard of myocardial viability imaging, in which scarred regions of the heart following myocardial infarction are visualized. However viability imaging faces image quality challenges in patients with severe arrhythmias and in cases where a higher spatial resolution, and hence a longer acquisition time, is desired. This thesis also proposes an arrhythmia insensitive inversion recovery (AIIR) algorithm that would significantly reduce artifacts that degrade image quality, thereby extending viability imaging to higher spatial resolution and in patients with severe arrhythmia. Simulations, experimental validation on phantoms and clinical verification on patients are performed.
Results from high temporal resolution imaging reveal that obtaining cine cardiac MR images at a temporal resolution of 6 ms per cardiac phase is feasible. Appropriate validated algorithms yield LV time-volume curve from which LV functional metrics are reliably extracted. A dependence on temporal resolution is revealed, and a temporal resolution cut-off of 12 ms is proposed to reliably capture the temporal dynamics of the LV. Also, results from cardiac viability imaging show that the AIIR algorithm performs significantly better than conventional imaging methods in both phantoms and human subjects, as shown by the blinded expert scores, leading to a better image quality.
In conclusion, this thesis proposes and implements methods that help cardiac MRI yield 1) a better function and wall motion assessment of the heart through high temporal resolution imaging and 2) a better assessment of myocardial viability through the AIIR algorithm.
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Sergančiųjų išemine širdies liga kairiojo skilvelio funkcijos ir morfometrijos pokyčiai po kairiojo skilvelio tūrio mažinimo operacijų / Left ventricular function and morphometry changes after left ventricular volume reduction surgery in patients with ischemic heart diseaseRaugelienė, Rūta 17 October 2006 (has links)
The aim of the study To evaluate functional status changes, LV function and morphometry changes in patients with ischemic heart disease one year after LV volume reduction surgery of two different types. The objectives of the study 1.To evaluate clinical and functional status changes in patients one year after LV volume reduction surgery of two different types and to determine prognostic value of preoperative LV functional parameters affecting functional status changes in patients one year after surgery. 2.To evaluate LV function and morphometry changes one year after LV volume reduction surgery of two different types and to determine prognostic value of preoperative LV parameters for LV remodeling one year after surgery. 3.To compare LV function and morphometry changes in patients with anterior and posterior myocardial infarction one year after LV volume reduction surgery. 4.To evaluate the changes of mitral regurgitation grade and its relations with LV functional parameters one year after LV volume reduction surgery with or without concomitant MV repair. 5.To evaluate survival and its predictors one year after LV volume reduction surgery.
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Investigating the adoption of ring operation in LV networks with PV systemsAydin, Muhammed Sait January 2017 (has links)
The ambitious governmental policies, particularly in Europe, in pursuit of established energy targets require an increase in distributed generation. As a result, photovoltaic (PV) technologies have emerged, predominantly at residential Low Voltage (LV) feeders. However, PV rich LV feeders are highly likely to pose technical challenges such as significant voltage rise and thermal overloading. This inevitably limits the volume of PV systems that can be hosted on LV feeders. Therefore, the deployment of solutions that can enable feeders to accommodate greater volumes of PV systems without having any technical issues is crucial. This thesis, consequently, thoroughly investigates one of the potential solutions: transforming the radial operation of LV feeders into ring operation. European-style LV feeders are typically operated in a radial fashion and yet are designed to be reconfigurable with neighbouring feeders. It is, therefore, essential to identify the best pairing option (of PV rich LV feeders) in a practical and straightforward manner due to the large number of existing LV feeders in a given Distribution Network Operator (DNO) area. This thesis proposes a generic innovative methodology to enable DNOs to straightforwardly identify the best pairing feeder; a decision-making tool to facilitate the rapid uptake of PV systems. To accomplish this goal, an impact assessment of a set of real residential LV feeders is carried out to identify the first technical issue/constraint that limits their hosting capacity. Next, regression analyses are carried out to gain an understanding of the relation between this first occurrence of technical issue/constraint and the corresponding level of PV penetration. The most practical and adequately accurate metric needs to be chosen. Feeders are then classified based on the range of metrics to cover all possible pairing cases. Finally, the ring operation of feeders in each class is analysed and hosting capacities are compared to those of radial ones. This process creates a practical matrix from which DNOs can easily identify the best pairing feeders. DNOs are likely to be hesitant to adopt permanent ring operation as it is not typically adopted in traditional LV feeders. Therefore, the switch located between feeders can be operated over time (i.e., dynamic ring operation) to reduce the duration for which ring operation is in place. It is, however, challenging to identify the most favourable control strategy. This thesis proposes different strategies for dynamic ring operation. Note that the most preferable control strategy is that which preserves the benefits of permanent ring operation with the minimum duration of ring operation and minimum number of switching. To achieve this, four different control strategies are explored-using different control cycles and considering hosting capacity, duration and switching. The best control strategy is found to be able to increase hosting capacity as permanent ring operation, reduce switching actions and minimise duration of ring operation compared to other proposed strategies and, crucially, operate ring operation only when it is truly needed. Finally, this thesis investigates the use of ring operation with an LV on-load tap changer (OLTC) as this is recently available voltage control technologies and is increasingly drawing the attention of DNOs. Two approaches are investigated to increase hosting capacity and limit ring operations: the use of the switch and OLTC are controlled separately using local measurements (i.e., localised) and their simultaneous control at the LV transformer level (i.e., centralised). The latter gives the priority to the OLTC to minimise the duration of the ring operation. The assessments are extended to cover an integrated medium and low voltage network to obtain more realistic results. The results show that centralised approach provides better performance considering hosting capacity, the number of switching/tap actions and the duration of ring operation.
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Rozptyl primárních elektronů na atomech zalévacího média biologického materiálu u nízkonapěťového transmisního elektronového mikroskopu LV EM 5 / Primary electron scattering on biological specimen embedding resins at low voltage transmission electron microscope LV EM 5BÍLÝ, Tomáš January 2011 (has links)
This master thesis deals with researching the structure of embedding resin in the Low-Voltage Transmission Electron Microscope (LV TEM). Further, it focuses on researching the surface morphology by the Atomic Force Microscope (AFM) and by the Scanning Electron Microscope (SEM). The principle of each of the microscopes is explained ? the contrast formation and construction of the LV TEM in particular. In the conclusion the evaluation of the effect of the surface structure of the embedding resin on the image contrast in the LV TEM and the analysis of the minimalization of its effect on the final image is given.
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Reactive Power Control for Voltage ManagementHasan, MD. Shakib January 2017 (has links)
This thesis presents methods for voltage management in distribution systems with high photovoltaic (PV) power production. The high PV penetration leads to both new challenges such as voltage profile violation and reverse power flow, and also new opportunities. Traditionally, the voltage control in the distribution network is achieved by common devices in the networks such as capacitor banks, static synchronous compensators (STATCOMs) and on-load tap changers (OLTCs). This thesis has considered existing reactive power capable solar PV inverters together with STATCOMs to provide voltage support for the distribution network. In this thesis, two effective coordination methods using the STATCOM and PV inverters are developed in order to study their interaction and how they together can stabilize the voltage level. Data from existing low-voltage (LV) and medium-voltage (MV) networks are used for a case study. The first control method is developed for LV network’s voltage control by means of PV inverter and STATCOM. The second control method is developed for both LV and MV networks’ voltage control, where reactive power control in PV inverters and STATCOMs are used in the LV network and only STATCOMs in the MV network. The control methods follow a hierarchical structure where reactive power compensation using PV inverters are prioritized. The STATCOMs, first in the LV and thereafter in the MV network in the second control method, are used only when the PV inverters are not able to provide or consume enough reactive power. This is beneficial due to the significant reduction in numbers of STATCOMs and their operation. The simulation results indicate that the proposed method is able to control both the over- and undervoltage situations for the test distribution networks. It is also shown that reactive power supply at night by the PV inverters can be an important resource for effective voltage regulation by using the proposed coordinated voltage control method.
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Orsaker till unga officerares avgångar / Recent resignations at the Air Defence Regiment : Experiences of young officersLundgren, Anders January 2009 (has links)
<p>När en nyutbildad officer som slutar är inte bara en ekonomisk förlust för Försvarsmakten, utan även en organisatorisk förlust eftersom brister i bemanningen inte går att åtgärda direkt. Medelåldern i Försvarsmakten har stigit de senaste åren. Syftet med denna uppsats är bidra till förståelse för varför unga officerare lämnar Försvarsmakten. Vid Luftvärnsregementet Lv 6 i Halmstad är medelåldern 40,6 år. Under de senaste fyra åren har sju unga officerare lämnat anställningen på regementet. Frågeställningarna som har besvarats är: Vilka är anledningarna till att de sju officerarna slutat på Luftvärnsregementet? – Finns det gemensamma orsaker? Delar andra officerare de erfarenheter som lett fram till avgångsbeslutet? - Av dessa, hur många funderar på att sluta?<em></em></p><p>Resultaten har nåtts genom intervjuer med sju officerare och en enkät där 686 unga officerare deltagit. Intervjuerna och svaren från enkäten ger en bild av att många unga officerare upplever stor arbetsbelastning och att det inte finns resurser i form av pengar eller personal att lösa tilldelade uppgifter. Officerare tvingas planera om verksamhet av besparingsskäl. Trots detta har majoriteten av enkätdeltagarna angett att förbandet bedriver en god utbildning av de värnpliktiga.</p> / <p>The average age in the Swedish Armed Forces has during the last four years increased from 39,5 to 42,2. According to a study from the 1990’s many young officers resign from the military organization, this is verified by the Swedish Armed Forces Headquarter. Becoming a commissioned officer in the Swedish Armed Forces requires three years of studies at a military academy. Young officers resigning from the Armed Forces lead to financial as well as organizational losses. This study aims to develop an understanding of the main reasons why young officers choose to find a career outside the Armed Forces. To do this seven young officers that have resigned from the Air Defence Regiment have been interviewed. A survey has been sent out to 686 officers that are still serving with the purpose of investigating whether they share similar experiences and if they are considering resigning the Armed Forces.</p><p>The most significant results show that the young officers tend not to feel appreciated by their superiors. Furthermore, Swedish officers experience that they are carrying a heavy workload. Some of the problems young officers are facing in their work situation are due to financial cutbacks.</p>
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Orsaker till unga officerares avgångar / Recent resignations at the Air Defence Regiment : Experiences of young officersLundgren, Anders January 2009 (has links)
När en nyutbildad officer som slutar är inte bara en ekonomisk förlust för Försvarsmakten, utan även en organisatorisk förlust eftersom brister i bemanningen inte går att åtgärda direkt. Medelåldern i Försvarsmakten har stigit de senaste åren. Syftet med denna uppsats är bidra till förståelse för varför unga officerare lämnar Försvarsmakten. Vid Luftvärnsregementet Lv 6 i Halmstad är medelåldern 40,6 år. Under de senaste fyra åren har sju unga officerare lämnat anställningen på regementet. Frågeställningarna som har besvarats är: Vilka är anledningarna till att de sju officerarna slutat på Luftvärnsregementet? – Finns det gemensamma orsaker? Delar andra officerare de erfarenheter som lett fram till avgångsbeslutet? - Av dessa, hur många funderar på att sluta? Resultaten har nåtts genom intervjuer med sju officerare och en enkät där 686 unga officerare deltagit. Intervjuerna och svaren från enkäten ger en bild av att många unga officerare upplever stor arbetsbelastning och att det inte finns resurser i form av pengar eller personal att lösa tilldelade uppgifter. Officerare tvingas planera om verksamhet av besparingsskäl. Trots detta har majoriteten av enkätdeltagarna angett att förbandet bedriver en god utbildning av de värnpliktiga. / The average age in the Swedish Armed Forces has during the last four years increased from 39,5 to 42,2. According to a study from the 1990’s many young officers resign from the military organization, this is verified by the Swedish Armed Forces Headquarter. Becoming a commissioned officer in the Swedish Armed Forces requires three years of studies at a military academy. Young officers resigning from the Armed Forces lead to financial as well as organizational losses. This study aims to develop an understanding of the main reasons why young officers choose to find a career outside the Armed Forces. To do this seven young officers that have resigned from the Air Defence Regiment have been interviewed. A survey has been sent out to 686 officers that are still serving with the purpose of investigating whether they share similar experiences and if they are considering resigning the Armed Forces. The most significant results show that the young officers tend not to feel appreciated by their superiors. Furthermore, Swedish officers experience that they are carrying a heavy workload. Some of the problems young officers are facing in their work situation are due to financial cutbacks.
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