Thomas Mannhart, KroneDB: Compressing and Querying Time Series Data using the Kronecker Decomposition, University of Zurich, Faculty of Business, Economics and Informatics, 2023. (Master's Thesis)
This thesis introduces the design of KroneDB, a system for compressing time series data using the Kronecker decomposition, while allowing for efficient evaluation of relational queries including selection, projection, join, and aggregates (SPJA). KroneDB allows for a tunable trade-off between compression ratio and approximation error, while exploiting periodic patterns within the data to improve the compression. The compressed data can be queried directly without prior decompression while reducing the runtime of most queries. Updates can be applied directly to the compressed data and naturally enable value imputation and outlier detection in the updating process. By embedding our approach into the Functional Aggregate Queries (FAQ) framework, we show that it can be applied to a wide range of fundamental problems. |
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Cornel Nesseler, Carlos Gomez Gonzalez, Petr Parshakov, Helmut Max Dietl, Examining discrimination against Jews in Italy with three natural field experiments, Journal of Behavioral and Experimental Economics, Vol. 106, 2023. (Journal Article)
We use three natural field experiments to examine anti-Semitism in Italy by sending email inquiries to amateur football clubs, landlords, and employers and comparing the response rates to emails sent with Jewish- and non-Jewish-sounding names. Italy is an interesting country as discrimination was heterogeneous and geographically unevenly distributed during World War II. We analyze if today's anti-Semitism in Italy is geographically correlated to the deportations and killings of Jews during the Holocaust. The results show significant discrimination when looking for football club and an apartment, but not when seeking a job. We find markedly different results for women. Comparing areas with different societal and economic implications provides us with a more informed perspective about the extent of discrimination. |
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Patricia Pálffy, Patrick Lehnert, Uschi Backes-Gellner, Social norms and gendered occupational choices of men and women: Time to turn the tide?, Industrial Relations, Vol. 62 (4), 2023. (Journal Article)
We analyze the relationship between social gender norms and adolescents' occupational choices by combining regional votes on constitutional amendments on gender equality with job application data from a large job board for apprenticeships. The results show that adolescent males in regions with stronger traditional social gender norms are more likely to apply for typically male occupations. This finding does not hold for females, suggesting that incentivizing men to break the norms and choose gender-atypical occupations (e.g., in healthcare) can be even more effective in accelerating advancement toward gender equality in the labor market than incentivizing women to choose STEM occupations. |
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Simona Nistor, Steven Ongena, The Impact of Policy Interventions on Systemic Risk across Banks, Journal of Financial Services Research, Vol. 64 (2), 2023. (Journal Article)
What is the impact of policy interventions on the systemic risk of banks? To answer this question, we analyze a comprehensive sample that combines an original set of bank-specific bailout events with the balance sheets of key affected and nonaffected European banks between 2005 and 2014. We find a positive and significant association of guarantees with systemic risk that is somewhat weaker in the long run when the regulator appoints members to the supervisory board. The short run association between recapitalizations and systemic risk is also positive for large and less capitalized banks, while in the long run, recapitalizations are linked with reduced systemic importance, especially for less profitable banks and in cases when the regulator limits management pay. Liquidity injections are positively linked with systemic risk, but the long-run effect is mitigated for small or better capitalized banks. In the short run, injecting liquidity is associated with reduced systemic risk when the regulator imposes restrictions on supervisory board composition or on management pay or capital payouts. |
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Daniel Fasnacht, D. Proba, Inter-Organizational Agility as Driving Force for Innovation, SAGE Open , Vol. forthcoming, 2023. (Journal Article)
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Nadine Kammerlander, Jochen Menges, Dennis Herhausen, Petra Kipfelsberger, Heike Bruch, How family CEOs affect employees’ feelings and behaviors: A study on positive emotions, Long Range Planning, Vol. 56 (5), 2023. (Journal Article)
Research suggests that firms with family CEOs differ from other types of businesses, yet surprisingly little is known about how employees in these firms feel and behave compared to those working in other firms. We draw from family science and management research to suggest that family CEOs, because of their emotion-evoking double role as family members and business leaders, are, on average, more likely to infuse employees with positive emotions, such as enthusiasm and excitement, than hired professional CEOs. We suggest that these emotions spread through firms by way of emotional contagion during interactions with employees, thereby setting the organizational affective tone. In turn, we hypothesize that in firms with family CEOs the voluntary turnover rate is lower. In considering structural features as boundary conditions, we propose that family CEOs have stronger effects in smaller and centralized firms, and weaker effects in formalized firms. Multilevel data from 41,200 employees and 2,246 direct reports of CEOs from 497 firms with and without family CEOs provide support for our model. This research suggests that firms managed by family CEOs, despite often being criticized as nepotistic relics of the past, tend to offer pleasant work environments. |
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Ernesto de León, Mykola Makhortykh, Teresa Gil-Lopez, Aleksandra Urman, Silke Adam, News, Threats, and Trust: How COVID-19 News Shaped Political Trust, and How Threat Perceptions Conditioned This Relationship, International Journal of Press/Politics, Vol. 28 (4), 2023. (Journal Article)
This study explores shifts in political trust during the outbreak of the COVID-19 pandemic in Switzerland, examining the role that media consumption and threat perceptions played in individuals’ trust in politics. We combine panel surveys taken before and during the first nation-wide lockdown with webtracking data of participants' online behaviour to paint a nuanced picture of media effects during the crisis. Our work has several findings. First, political trust, an attitude known for its stability, increased following lockdown. Second, consumption of mainstream news on COVID-19 directly hindered this increase, with those reading more news having lower over-time trust, while the relatively minor alternative news consumption had no direct effect on political trust. Third, threat perceptions a) to health and b) from the policy response to the pandemic, have strong and opposite effects on political trust, with threats to health increasing trust, and threats from the government policy response decreasing it. Lastly, these threat perceptions condition the effect of COVID-19 news consumption on political trust: perceptions of threat had the power to both exacerbate and mute the effect of media consumption on government trust during the pandemic. Notably, we show that the expected negative effect of alternative news on political trust only exists for those who did not think COVID-19 posed a threat to their health, while public service news consumption reduced the negative effect produced by government threat perceptions. The paper therefore advances our understanding of the nuanced nature of media effects, particularly as relates to alternative media, especially during moments of crisis. |
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Igor Letina, Shuo Liu, Nick Netzer, Optimal contest design: tuning the heat, Journal of Economic Theory, Vol. 213, 2023. (Journal Article)
We consider the design of contests when the principal can choose both the prize profile and how the prizes are allocated as a function of a possibly noisy signal about the agents' efforts. We provide sufficient conditions that guarantee optimality of a contest. Optimal contests have a minimally competitive prize profile and an intermediate degree of competitiveness in the contest success function. Whenever observation is not too noisy, the optimum can be achieved by an all-pay contest with a cap. When observation is perfect, the optimum can also be achieved by a nested Tullock contest. We relate our results to a recent literature which has asked similar questions but has typically focused on the design of either the prize profile or the contest success function. |
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Mateusz Dolata, Gerhard Schwabe, Moving beyond privacy and airspace safety: Guidelines for just drones in policing, Government Information Quarterly, Vol. 40 (4), 2023. (Journal Article)
The use of drones offers police forces potential gains in efficiency and safety. However, their use may also harm public perception of the police if drones are refused. Therefore, police forces should consider the perception of bystanders and broader society to maximize drones' potential. This article examines the concerns expressed by members of the public during a field trial involving 52 test participants. Analysis of the group interviews suggests that their worries go beyond airspace safety and privacy, broadly dis-cussed in existing literature and regulations. The interpretation of the results indicates that the perceived justice of drone use is a significant factor in acceptance. Leveraging the concept of organizational justice and data collected, we propose a catalogue of guidelines for just operation of drones to supplement the existing policy. We present the organizational justice perspective as a framework to integrate the concerns of the public and bystanders into legal work. Finally, we discuss the relevance of justice for the legitimacy of the police's actions and provide implications for research and practice. |
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Christoph Basten, Mike Mariathasan, Interest rate pass-through and bank risk-taking under negative-rate policies with tiered remuneration of central bank reserves, Journal of Financial Stability, Vol. 68, 2023. (Journal Article)
We identify the effects of negative rates on bank behavior using difference-in-differences identification. First, we find that going negative can interrupt not only the pass-through from policy to deposit but also to mortgage rates. To preserve their deposit franchise, banks finance negative deposit with increased mortgage spreads, the more the bigger their market power. Second, negative rates on reserves induce banks to cut some reserves without replacement and replace others with riskier assets. Together with increased mortgage spreads, balance sheet restructuring preserves profits but risk-taking increases. Third, pass-through interruption and risk-taking can be reduced through tiered remuneration. |
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Reto Eberle, Swiss Audit Monitor 2023: Analyse des Revisionsmarkts der kotierten Unternehmen in der Schweiz, Expert Focus, Vol. 2023 (Oktober), 2023. (Journal Article)
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Madhav Sachdeva, Jan Burmeister, Jörn Kohlhammer, Jürgen Bernard, LFPeers: Temporal similarity search and result exploration, Computers & Graphics, Vol. 115, 2023. (Journal Article)
In this paper, we introduce a general concept for the analysis of temporal and multivariate data and the system LFPeers that applies this concept to temporal similarity search and results exploration. The conceptual workflow divides the analysis in two phases: a search phase to find the most similar objects to a query object before a time point in the temporal data, and an exploration phase to analyze and contextualize this subset of objects after . LFPeers enables users to search for peers through interactive similarity search and filtering, explore interesting behavior of this peer group, and learn from peers through the assessment of diverging behaviors. We present the conceptual workflow to learn from peers and the LFPeers system with novel interfaces for search and exploration in temporal and multivariate data. An earlier workshop publication for LFPeers included a usage scenario targeting epidemiologists and the public who want to learn from the Covid-19 pandemic and distinguish successful and ineffective measures. In this extended paper, we now show how our concept is generalized and applied by domain experts in two case studies, including a novel case on stocks data. Finally, we reflect on the new state of development and on the insights gained by the experts in the case studies on the search and exploration of temporal data to learn from peers. |
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Alessandro Ferrari, Matteo Fiorini, Joseph Francois, Bernard Hoekman, Lisa Lechner, Miriam Manchin, Filippo Santi, EU trade agreements and non-trade policy objectives, In: Coherence of the European Union trade policy with its non-trade objectives: World Trade Forum, Cambridge University Press, Cambridge, p. 180 - 207, 2023-10. (Book Chapter)
The EU’s common commercial policy is used as an instrument to realize its values in EU trading partners, reflected in the inclusion of sustainable trade and development chapters in EU preferential trade agreements (PTAs). This chapter asks if including non-trade provisions (NTPs) in EU PTAs has a systematic positive effect on non-trade outcomes in partner countries. It analyzes the relationship between bilateral trade flows, the coverage of NTPs in EU PTAs and the performance of EU partner countries on several non-trade outcome variables using synthetic control methods. It finds no robust evidence of a causal effect of including NTPs in EU PTAs on indicators of non-trade outcomes. |
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Ling Gao, Hang Sun, Daniel Gehrig, Marco Cannici, Davide Scaramuzza, Laurent Kneip, A 5-Point Minimal Solver for Event Camera Relative Motion Estimation, In: 2023 IEEE/CVF International Conference on Computer Vision (ICCV), 2023-10-01. (Conference or Workshop Paper published in Proceedings)
Event-based cameras are ideal for line-based motion estimation, since they predominantly respond to edges in the scene. However, accurately determining the camera displacement based on events continues to be an open problem. This is because line feature extraction and dynamics estimation are tightly coupled when using event cameras, and no precise model is currently available for describing the complex structures generated by lines in the space-time volume of events. We solve this problem by deriving the correct non-linear parametrization of such manifolds, which we term eventails, and demonstrate its application to eventbased linear motion estimation, with known rotation from an Inertial Measurement Unit. Using this parametrization, we introduce a novel minimal 5-point solver that jointly estimates line parameters and linear camera velocity projections, which can be fused into a single, averaged linear velocity when considering multiple lines. We demonstrate on both synthetic and real data that our solver generates more stable relative motion estimates than other methods while capturing more inliers than clustering based on spatiotemporal planes. In particular, our method consistently achieves a 100% success rate in estimating linear velocity where existing closed-form solvers only achieve between 23% and 70%. The proposed eventails contribute to a better understanding of spatio-temporal event-generated geometries and we thus believe it will become a core building block of future event-based motion estimation algorithms. |
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Nikola Zubić, Daniel Gehrig, Mathias Gehrig, Davide Scaramuzza, From Chaos Comes Order: Ordering Event Representations for Object Recognition and Detection, In: 2023 IEEE/CVF International Conference on Computer Vision (ICCV), Computer Vision Foundation, 2023-10-01. (Conference or Workshop Paper published in Proceedings)
Today, state-of-the-art deep neural networks that process events first convert them into dense, grid-like input representations before using an off-the-shelf network. However, selecting the appropriate representation for the task traditionally requires training a neural network for each representation and selecting the best one based on the validation score, which is very time-consuming. This work eliminates this bottleneck by selecting representations based on the Gromov-Wasserstein Discrepancy (GWD) between raw events and their representation. It is about 200 times faster to compute than training a neural network and preserves the task performance ranking of event representations across multiple representations, network backbones, datasets, and tasks. Thus finding representations with high task scores is equivalent to finding representations with a low GWD. We use this insight to, for the first time, perform a hyperparameter search on a large family of event representations, revealing new and powerful representations that exceed the state-of-the-art. Our optimized representations outperform existing representations by 1.7 mAP on the 1 Mpx dataset and 0.3 mAP on the Gen1 dataset, two established object detection benchmarks, and reach a 3.8% higher classification score on the mini N-ImageNet benchmark. Moreover, we outperform state-of-the-art by 2.1 mAP on Gen1 and state-of-the-art feed-forward methods by 6.0 mAP on the 1 Mpx datasets. This work opens a new unexplored field of explicit representation optimization for event-based learning. |
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Jiawei Fu, Yunlong Song, Yan Wu, Fisher Yu, Davide Scaramuzza, Learning Deep Sensorimotor Policies for Vision-Based Autonomous Drone Racing, In: 2023 IEEE/RSJ International Conference on Intelligent Robots and Systems, IROS 2023, Institute of Electrical and Electronics Engineers, 2023. (Conference or Workshop Paper published in Proceedings)
The development of effective vision-based algorithms has been a significant challenge in achieving autonomous drones, which promise to offer immense potential for many real-world applications. This paper investigates learning deep sensorimotor policies for vision-based drone racing, which is a particularly demanding setting for testing the limits of an algorithm. Our method combines feature representation learning to extract task-relevant feature representations from high-dimensional image inputs with a learning-by-cheating framework to train a deep sensorimotor policy for vision-based drone racing. This approach eliminates the need for globally-consistent state estimation, trajectory planning, and handcrafted control design, allowing the policy to directly infer control commands from raw images, similar to human pilots. We conduct experiments using a realistic simulator and show that our vision-based policy can achieve state-of-the-art racing performance while being robust against unseen visual disturbances. Our study suggests that consistent feature embeddings are essential for achieving robust control performance in the presence of visual disturbances. The key to acquiring consistent feature embeddings is utilizing contrastive learning along with data augmentation. |
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Jiaxu Xing, Giovanni Cioffi, Javier Hidalgo-Carrio, Davide Scaramuzza, Autonomous Power Line Inspection with Drones via Perception-Aware MPC, In: 2023 IEEE/RSJ International Conference on Intelligent Robots and Systems, IROS 2023, Institute of Electrical and Electronics Engineers, 2023. (Conference or Workshop Paper published in Proceedings)
Drones have the potential to revolutionize power line inspection by increasing productivity, reducing inspection time, improving data quality, and eliminating the risks for human operators. Current state-of-the-art systems for power line inspection have two shortcomings: (i) control is decoupled from perception and needs accurate information about the location of the power lines and masts; (ii) obstacle avoidance is decoupled from the power line tracking, which results in poor tracking in the vicinity of the power masts, and, consequently, in decreased data quality for visual inspection. In this work, we propose a model predictive controller (MPC) that overcomes these limitations by tightly coupling perception and action. Our controller generates commands that maximize the visibility of the power lines while, at the same time, safely avoiding the power masts. For power line detection, we propose a lightweight learning-based detector that is trained only on synthetic data and is able to transfer zero-shot to real-world power line images. We validate our system in simulation and real-world experiments on a mock-up power line infrastructure. We release our code and datasets to the public. |
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Oscar Arce, Miguel García-Posada, Sergio Mayordomo, Steven Ongena, Bank lending policies and monetary policy: some lessons from the negative interest era, Economic Policy, Vol. 38 (116), 2023. (Journal Article)
What is the long-term impact of negative interest rates on bank lending? To answer this question, we construct a unique summary measure of negative rate exposure by individual banks based on exclusive survey data and banks’ balance sheets and couple it with the credit register of Spain and firms’ balance sheets to identify this impact on the supply of credit to firms. We find that only when deposit rates reached the zero lower bound did affected banks (relative to non-affected banks) decrease their supply, especially when undercapitalized and lending to risky firms. The adverse effects of the negative rates on banks’ intermediation capacity only took place after a protracted period of time. |
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Reto Eberle, Kurt Speck, «Am Beginn der Lernkurve»: Der Professor an der Universität Zürich und Partner bei KPMG zu den Herausforderungen der Branche, In: Handelszeitung, p. 51, 28 September 2023. (Newspaper Article)
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Haiyan Yang, Renato Pajarola, Visual-assisted Outlier Preservation for Scatterplot Sampling, In: VMV: Vision, Modeling, and Visualization, The Eurographics Association, 2023. (Conference or Workshop Paper published in Proceedings)
Scatterplot sampling has long been an efficient and effective way to resolve the overplotting issues commonly occurring in large-scale scatterplot visualization applications. However, it is challenging to preserve the existence of low-density points or outliers after sampling for a sub-sampling algorithm if, at the same time, faithfully representing the relative data densities is of importance. In this work, we propose to address this issue in a visual-assisted manner. While the whole dataset is sub-sampled, the density of the outliers is modeled and visually integrated into the final scatterplot together with the sub-sampled point data.
We showcase the effectiveness of our proposed method in various cases and user studies. |
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