A spatial autoregressive stochastic frontier model for panel data with asymmetric efficiency spillovers

By blending seminal literature on non-spatial stochastic frontier models with key contributions to spatial econometrics we develop a spatial autoregressive (SAR) stochastic frontier for panel data. The specification of the SAR frontier allows efficiency to vary over time and across the cross-sections. Efficiency is calculated from a composed error structure by assuming a half-normal distribution for inefficiency. The SAR frontier is estimated using maximum likelihood methods taking into account the endogenous SAR variable. The application of the estimator to an aggregate production frontier for European countries highlights, among other things, the asymmetry between efficiency spillovers to and from a country

What Is One Grain of Sand in the Desert? Analyzing Individual Neurons in Deep NLP Models

Despite the remarkable evolution of deep neural networks in natural language processing (NLP), their interpretability remains a challenge. Previous work largely focused on what these models learn at the representation level. We break this analysis down further and study individual dimensions (neurons) in the vector representation learned by end-to-end neural models in NLP tasks. We propose two methods: Linguistic Correlation Analysis, based on a supervised method to extract the most relevant neurons with respect to an extrinsic task, and Cross-model Correlation Analysis, an unsupervised method to extract salient neurons w.r.t. the model itself. We evaluate the effectiveness of our techniques by ablating the identified neurons and reevaluating the network's performance for two tasks: neural machine translation (NMT) and neural language modeling (NLM). We further present a comprehensive analysis of neurons with the aim to address the following questions: i) how localized or distributed are different linguistic properties in the models? ii) are certain neurons exclusive to some properties and not others? iii) is the information more or less distributed in NMT vs. NLM? and iv) how important are the neurons identified through the linguistic correlation method to the overall task? Our code is publicly available as part of the NeuroX toolkit (Dalvi et al. 2019).Comment: AAA 2019, pages 10, AAAI Conference on Artificial Intelligence (AAAI 2019

Returns to scale and curvature in the presence of spillovers: evidence from European countries

Drawing on a recent development on the interpretation of spatial econometric models we extend two classic characteristics of production (returns to scale and diminishing marginal productivity of factor inputs) to the spatial case. In the context of a spatial translog production function we deÖne internal (i.e. direct), external (i.e. indirect) and total (direct plus indirect) returns to scale. The spatial production function gives rise to direct, indirect and total productions functions so we set out empirical checks to establish if these functions are concave. The ideas of spatial returns to scale and spatial concavity/convexity can easily be applied to other technologies (e.g. cost and distance functions) and other functional forms (e.g. Cobb-Douglas). We apply these ideas to aggregate production of European countries using balanced panel data for the period 1990 2011

Estimating efficiency spillovers with state level evidence for manufacturing in the US

Unit specific effects are often used to estimate non-spatial efficiency. We extend such estimators to the case where there is spatial autoregressive dependence and introduce the concept of spillover efficiency. Intuitively, we present an approach to benchmark how successful units are at exporting and importing productive performance to and from other units

Game, set and match: evaluating the efficiency of male professional tennis players

We exploit the natural distinction between the attacking and defensive aspects of tennis to get a better understanding of the origins of relative inefficiency. Attacking is simply when a player is serving and defending is when a player is returning serve. We use data envelopment analysis (DEA) to compute the attacking, defensive and overall efficiencies of the top 100 male professional players for the 2009 season. An analysis of the efficiency scores using non-parametric kernel smoothing suggests that there are four groups of players in the sample- those that are relatively efficient in attack and defence; those that are relatively inefficient in attack and defence; and those that are relatively efficient in attack or defence. Truncated regression equations for the technical and super attacking, defensive and overall efficiencies as a function of off-court variables (e.g. height, age, etc.) suggest that being a left-handed player has a significant positive effect on the overall efficiencies

Bank performance and the financial crisis: evidence from Kazakhstan

During the first phase of the financial crisis in 2008/09, after Iceland and Belgium, Kazakhstan experienced the most significant bank failures as a share of bank system assets. Using rich monthly data for virtually the entire Kazakh banking industry for the period March 2007 - December 2010, Stochastic Frontier Analysis (SFA) is used to fit several functions (cost, revenue, standard profit, alternative profit and input distance). Among other things, we estimate the effects of two measures of the quality and risk of the loan portfolio on the industry best practice frontiers and bank inefficiencies. We find that an increase in the volume of bad loans as a ratio of total lending has a desirable effect on the cost, input-distance and alternative profit frontiers, all of which is consistent with the ‘skimping’ hypothesis

Investigation of thermodynamic factors influencing Thorium reactor efficiencies

In this meta-study, the major forms of thorium based nuclear reactors were compared using thermodynamic parameters to find which reactor type holds the highest thermodynamic efficiency and hence, determine which reactor would be most beneficial to research further and implement for energy production. Our study found that molten salt reactors had the best thermodynamic efficiency and also runs at one atmospheric pressure, making it safer than conventional water reactors. The findings in this study show molten salt reactors would be the most efficient reactor to replace standard water reactors, which dominate the market in use of nuclear energy production. This study found a strong link between the thermal efficiency of the plant and the pressure and temperature at which it runs. Reactor core volumes also appeared to have a small effect on the efficiencies. Power flux density was calculated for each style of reactor and compared to other parameters but no distinct relationship was found between them.

Professionalisierung des Gerichtsdolmetschens im Kanton Zürich: empirische Studie zur Umsetzung der Dolmetscherverordnung

Zürich is the first canton in German-speaking Switzerland to have introduced legally-based quality standards for interpreters working at courts and for public authorities. The 2004 Interpreter’s By-Law (Dolmetscherverordnung) regulates all interpreting and translation work ordered by such cantonal institutions. A special Experts’ Committee (Fachgruppe Dolmetscherwesen) is responsible for implicating the by-law by issuing guidelines for interpreters and their clients. One example of such a guideline is an information sheet for judges (and, by extension) other clients within the judicial system, containing tips on how to work with interpreters. The following article will discuss data from a survey conducted among court interpreters in Zürich (as part of a master thesis, cf. Glass 2010), particularly those parts of the survey that refer directly to the aforementioned information sheet. The main focus lies on the question if, or to what extent, judges actually follow the advice given in such guidelines, and whether interpreters are receiving enough support when preparing and carrying out their work. The results of the survey would seem to suggest that even though regulations are crucial in any attempt to increase professionalisation, only an awareness of the necessity of cooperating with interpreters can truly make a difference.Zürich ist der erste deutschschweizer Kanton, der eine verbindliche Qualitätsnorm für Behörden- und Gerichtsdolmetscher eingeführt hat. Die Dolmetscherverordnung (DolmV) von 2004 regelt sämtliche durch kantonale Gerichte und Behörden erteilten Dolmetsch- und Übersetzungsaufträge. Eine spezielle Fachgruppe hat die Aufgabe, die Anwendung der Dolmetscherverordnung mittels Richtlinien für Dolmetscher und Auftraggeber zu gewährleisten. Ein Beispiel einer solchen Richtlinie ist ein Merkblatt für Richter und (sinngemäss) für Staatsanwälte und Mitarbeiter der Polizei mit Tipps zur Zusammenarbeit mit Dolmetschern. Im folgenden Artikel werden diejenigen Ergebnisse einer (im Rahmen einer Masterarbeit, s. Glass 2010) unter Behörden- und GerichtsdolmetscherInnen im Kanton Zürich durchgeführten Umfrage vorgestellt, die unmittelbar auf das Merkblatt Bezug nehmen. Dabei steht die Frage im Mittelpunkt, ob bzw. inwiefern die Ratschläge im Merkblatt auch in der Praxis durch Richter angewendet werden, und ob DolmetscherInnen bei der Vorbereitung und Ausführung ihrer Arbeit genügend unterstützt werden. Die Ergebnisse der Umfrage legen nahe, dass Regelungen zwar für eine erhöhte Professionalisierung von entscheidender Bedeutung sind, dass letztendlich jedoch ein Bewusstsein für die Notwendigkeit einer Zusammenarbeit mit den DolmetscherInnen ausschlaggebend ist

The rise and fall of railtrack plc: an event study

Forming Railtrack was a key part of the privatisation of British Rail (BR). Railtrack took over ownership of BR's fixed infrastructure in April 1994 and its parent company, the Railtrack Group, was floated in May 1996 on the London Stock Exchange. Despite the group posting some excellent financial results in the early years, Railtrack's record on infrastructure improvement and safety was frequently criticised. This apparent inconsistency between shareholder interests and public service obligations culminated in Railtrack being placed in administration in October 2001. In view of this apparent inconsistency the reaction of the stock market to 19 key events in modelled. Among other things, we find when Railtrack announced after the Hatfield crash that there would be a six month programme of emergency track repairs, the group's share price was marked down but it did not plummet. Even though Railtrack were in panic mode, it appears that investors decided to hold on to their shares, believing that the panic would have no long term repurcussions. This proved to be a huge error of judgement