170 research outputs found
Nachtrag: Mindestlohn, Mütterrente, Pkw-Maut: Geht die Koalitionsvereinbarung zu Lasten der Wirtschaft und der Steuerzahler?
No full textErgänzend zu den Beiträgen im ifo Schnelldienst Nr. 2/2014 äußern sich Christoph M. Schmidt, RWI und Sachverständigenrat und Benjamin Weigert, Sachverständigenrat, zu den Koalitionsvereinbarungen. Ihrer Ansicht nach vernachlässigt die Wirtschaftspolitik die Frage, wie die Herausforderungen der Zukunft gemeistert werden sollen
Educational and Wage Risk: Social Insurance vs. Quality of Education
No full textIn this model of education, where individuals are exposed both to educational risk and to wage risk within the skilled sector, successful graduation depends both on individual effort to study and on public resources. We show that insuring the present risks is a dichotomic task: Wage risk is diversified ex post among the skilled by graduate taxation and skill-specific tuition fees. Educational risk of failure and inequality between skilled and unskilled workers are mitigated ex ante by enhancing the quality of education. The necessary expenditures are optimally financed by regressive tuition fees and the net revenue from the graduate tax.human capital investment, educational risk, wage risk, learning effort, graduate taxation, regressive tuition fees
Label-Efficient Deep Learning Methods for Event Detection, Object Segmentation and Cell Tracking in Biological Microscopy Images
No full textMicroscopy is one of the essential tools to quantify and advance our understanding of living systems. Modern digital microscopes enable measurements at unprecedented spatiotemporal scale, so automated processing methods are required to complete tasks such as object detection, segmentation and tracking, which enable further biological analysis.
While such methods can be carefully engineered for specific problems and datasets, the paradigm of supervised machine learning offers an attractive alternative: Functions can be learned from paired input-output examples, e.g. images paired with manually created object masks for segmentation.
This paradigm has revolutionized data processing, but relies on manually annotating considerable amounts of data for the problems to be solved, which is often the implementation and performance bottleneck in current bioimage processing algorithms.
This thesis proposes three complementary approaches for using human annotations efficiently.
The first approach is to develop algorithms that are robust to variations in imaging conditions or biological samples, and thereby reducing the amount of manual annotations needed for novel datasets.
Such domain gaps are particularly pronounced in volume electron microscopy (EM) images.
To this end, I propose a simple and practical pipeline with a 3D convolutional network at its core to segment targeted subcellular structures, which only needs curated coarse annotations and successfully balances model capacity and model generalization to slightly different datasets. It exhibits promising generalizability across volume EM datasets, and employs efficient fine-tuning for improving model performance on previously unseen data.
This method is employed to segment structures of different scales and complexity, for example mitochondria, endoplasmic reticulum, and nuclear pores.
The second approach is to train one unified large deep learning model
that combines existing annotations from different domains efficiently for achieving a general task, which alleviates fine-tuning on new datasets.
I propose a transformer-based model for cell tracking in live-cell microscopy that successfully approximates the discrete problem of linking cell detections across time frames for extracting ancestry lineages.
This unified yet flexible approach is a state-of-the-art cell tracking algorithm for different imaging datasets without the need for parameter tuning, ranging from cell cultures with fluorescently tagged nuclei over bacteria colonies up to developing embryos imaged in 3D. Additionally, it enables robust cell tracking even at low frame rates.
The third approach is to develop self-supervised learning algorithms that can extract information from unannotated data, which represents the majority of acquired microscopy datasets.
After presenting initial results on contrastive pre-training for instance segmentation, I propose a novel pre-training strategy for live imaging videos that uses time arrow prediction (TAP) to capture the inherently time-asymmetric dynamics of biological processes in unlabeled datasets.
I show that the spatiotemporal attribution maps of TAP are a powerful tool for discovering biological patterns such as the cell cycle, and that using TAP representations substantially reduces the amount of required human-annotated data for various downstream tasks including cell division detection and segmentation as well as cell state classification.UPDALP
Vier Aufsätze über internationalen Handel und den Arbeitsmarkt
No full textThe following dissertation is a collection of four stand-alone research papers. The common theme of all papers is the analysis of the decision of heterogeneous individuals about investing in education. The first paper analyses how these decisions affect the impact of globalisation or technological change on the income distribution. The second and the third paper focus on the distributional effects of human-capital investments in the presence of immigration. The fourth paper discusses the interplay of globalisation and alternative formulations of the institutional framework of the educational system.publishe
Das Verrechnungssystem der Federal Reserve und seine Übertragbarkeit auf den Euroraum
No full textIn der aktuellen Debatte über die Target2-Salden im Eurosystem wurde zu deren Abbau das Ausgleichsverfahren der Federal Reserve in den USA vorgeschlagen. Der dortige Ausgleichsmechanismus ist jedoch rein bilanzieller Natur und führt lediglich zu einer Neuaufteilung der Aktivseite des konsolidierten Notenbanksystems auf die Teilnotenbanken. Insbesondere bietet dieses Verfahren keine Möglichkeit, den Aufbau der Verrechnungssalden bereits im Vorfeld zu verhindern. Der diskutierte Ausgleich der Target2-Salden beseitigt bestenfalls die Symptome der Krise, er trägt für sich genommen nicht zu deren Lösung bei
Eurokrise: Erneute Atempause ist kein Grund zum Ausruhen
No full textThe current state of affairs in the euro area (EA) instills hope in economic recovery but also substantial concern. The crisis countries have made considerable, albeit quite uneven, progress in central areas of reform. Yet severe obstacles remain. Moreover, European policy makers have reformed the EA's institutional framework to strengthen its resilience. Yet important elements of a stable architecture are still missing, and it remains unclear whether the EA is moving towards full integration or a Maastricht 2.0. Most importantly, since it has become impossible to construct a viable fiscal bridge due to the success of the OMT programme, now everything depends on the perseverance of domestic reform policies
Immigration, education and labour market institutions
No full textIn this paper we analyse the effect of immigration on the labour market conditions for different skill groups. We develop a model of endogenous labour supply in which immigration affects educational decisions. We show how the skill premium changes with immigration of low skilled labour under flexible and rigid wages. Depending on the labour market institutions, immigration of low skilled labour is absorbed either by an increased skill premium or increased unemployment of low skilled labour. Thus, we extend the existing explanations of changing skill premia and unemployment of low skilled labour experienced during the last decades. Our model gives a rationale for the debate on immigration of high skilled workers as a way to reduce unemployment of low skilled workers in highly rigid labour markets.publishe
Determinants of sovereign yield spreads during the Euro-crisis: Fundamental factors versus systemic risk
No full textThe intensity of the Euro-crisis was reflected by significant increases of sovereign bond yields in the troubled countries. This has launched a hot debate whether this increase can solely be attributed to fundamental factors like e.g. rescue programmes, rising budget deficits, deteriorating economic prospects or changes in the rating-status of the country, or whether a part of these growing yields is likely to represent a systemic risk, i.e. that one or more countries will drop out of the European Monetary Union and reintroduce their own national currencies. This empirical analysis explores whether such systemic risk is present in the yield spreads of nine Euro area countries by using a novel market based indicator from the virtual prediction market Intrade. Our empirical results suggest that beside fundamental factors a systemic risk component played a role in determination of sovereign yields. Our empirical measure of the systemic component in sovereign yields can be related to the expected change of the newly introduced national currency. Accordingly to that, Portugal, Ireland, Spain and Italy are expected to depreciate their currency while the others would appreciate after a withdrawal from the Euro area. Risk premia that are related to fears of the reversibility of the Euro are unacceptable, and they need to be addressed in a fundamental manner. (ECB-President Mario Draghi, August 2012) Es gibt fundamentale Zweifel der Märkte an der Sicherheit der Währungsunion. (Bundesbankpräsident Jens Weidmann, July 2012
Does composition matter? Wage inequality and the demographic and educational structure of the labor force in Gemany
No full textThis paper addresses the importance of compositional changes in the labor force for the development of the wage distribution. Demographic change and higher educational attainment imply a shift toward employees with more experience and/or better education. These groups are characterized by higher relative wages as well as higher within-group wage inequality. Mechanically, these compositional shifts entail a rise in wage inequality. We demonstrate this mechanism theoretically and present empirical evidence using data of the German Socio-Economic Panel from the mid 1990's to 2012. Accounting for the parallel changes in the age structure and the educational background of the labor force, the compositional effects alone can explain up to one quarter of the observed increase in aggregate wage inequality
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