Renewable technology expands geographically and in capacity. The long transmission distance and bulk power transfer involved make multi-terminal VSC-HVDC systems a key technology for future power systems. This expansion could be hampered by the pace of development of multi-terminal systems especially when standardization is not reached in hardware or the control system. A general control system st

DC grids will play a key role in the future, interconnecting generation and load centers as well as energy markets. Large multi-terminal VSC-HVDC systems of high capacity will require automated coordination for several operation scenarios especially when operating under disturbances. With this in mind, and considering the dynamics of a DC system, communication loss events are considered severe dis

In this paper a new Space Vector Pulse Width Modulation method is proposed for multilevel voltage source inverters. This method is based on Space Vector Modulation and is compared to other similar methods. According to the method presented the multiplicity of the switching states of a multilevel inverter is also considered. This means that the new pulse method takes into account the multiplicity o

The commentary addresses the scope for synergy between climate change policy and social policy in the European Union (EU) from a ‘sustainable welfare’ perspective. The emerging sustainable welfare approach is oriented to the satisfaction of human needs within ecological limits, in an intergenerational and global perspective. While the overall goals of EU climate policy and EU welfare policies larg

This thesis analyses the Spanish tax system between 1960 and 1990, with special attention to its effects on the income distribution. It provides with a quantitative consistent evaluation of the reforms that took place during transition to democracy.Because of the long dictatorship suffered by the country between 1936/39 and1976, Spain introduced the 20th Century tax ideas with a considerable lag w

This paper presents a calibration technique for massive MIMO base stations, where the frequency responses of the transmit and/or receive analog front-ends are individually estimated and compensated for. Calibration is achieved by a first-round of channel sounding between base station antennas, followed by post-processing and a compensation stage. The proposed technique is general in the sense that

We assess the validity of differences in eligibility ages for early and old age pension benefits as instruments for estimating the effect of retirement on cognitive functioning. Because differences in eligibility ages across country and gender are correlated with differences in years of schooling, which affect cognitive functioning at old ages, they are invalid as instruments without controlling f

Background: Unwarranted variation in care practice and outcomes has gained attention and inter-hospital comparisons are increasingly being used to highlight and understand differences between hospitals. Adjustment for case mix is a prerequisite for meaningful comparisons between hospitals with different patient populations. The objective of this study was to identify and quantify maternal characte

The renal risks associated with long-term lithium treatment are a growing concern. We have therefore studied renal function by means of glomerular filtration rate (GFR) and maximum urinary concentrating capacity (Umax) in 142 of 215 patients with more than 15 years of lithium treatment in nine psychiatric clinics. Data on psychiatric and somatic diseases, hospital admissions, cumulative lithium do

A three-column ion chromatographic system for the removal of humic substances from natural waters, and subsequent on-line concentration and determination of nitrate and sulfate using non-suppressed ion chromatography is presented. Humic substances are removed using disposable adsorption columns packed with chemically bonded amine silica material. The sample is directly transfered to an ion exchang

Successful enlargement of the small aortic root in children has remained a management challenge, particularly in the neonates and small infants. Achieving this aim requires thorough understanding of the anatomic features of the left ventricular outflow tract, careful patient selection, and skilful execution of complex surgery. This article reviews the anatomical principles upon which the surgical

Debattartikel om utredningsdirektiv för lagstiftning om hemlig dataavläsning. Artikeln diskuterar den principiellt viktiga frågan om hur långt man kan gå för att skydda ett öppet och fritt demokratisk samhälle med polisiära övervakningsbefogenheter innan det där fria och öppna börja tummas på av själva befogenheterna, och tar utöver den avvägningsproblematiken upp risken med att upprätthålla säker

The problem of planning a trajectory for robots starting in an initial state and reaching a final state in a desired interval of time is tackled. We consider Model Predictive Control as an approach to the problem of point-to-point trajectory generation. We use the developed strategy to generate trajectories for transferring the state of the robot, fulfilling computational real-time requirements. E

We consider an iterative learning control (ILC) approach to machining with industrial robots. The robot and the milling process are modeled using system identification methods with a data-driven approach. Two different model-based ILC algorithms are proposed and subsequently experimentally verified in a milling scenario. The difference between the two approaches is the required sensors for acquiri

Objective: The aim of this study was to compare the outcome of immediate versus delayed radical prostatectomy (RP) in men with low-grade prostate cancer. Materials and methods: The study included a nationwide population-based cohort in the National Prostate Cancer Register of Sweden, of 7608 men with clinically localized, biopsy Gleason score 6 prostate cancer who underwent immediate or delayed RP

The emerging new idea of lane-keeping electronic stability control is investigated. In a critical situation, such as entering a road curve at excessive speed, the optimal behavior may differ from the behavior of traditional ESC, for example, by prioritizing braking over steering response. The important question that naturally arises is if this has a significant effect on safety. The main contribut