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Networks with spatially distributed externalities
Full text linkRegulating spatially distributed pollution poses a big challenge as the standard regulating instruments such as cap-and-trade or command-and-control systems that usually implement an efficient allocation do not work facing spatially distributed pollution or an authority to enforce them is missing. The problem of optimal pollution control is further aggravated by the presence of asymmetric information as many governments face limitations in monitoring the mitigation costs or the pollution flows. In this thesis, I consider multi-polluter networks and analyse if and to what extent the efficient levels of pollution can be implemented by voluntary agreements or regulatory instruments when pollution is spatially distributed. The thesis consists of three chapters.
In chapter 1, co-authored with Ralph Winkler, we consider the problem of efficient emission abatement in a multi-polluter setting, where agents are located along a river in which net emissions accumulate and induce negative externalities to downstream riparians. Assuming a cooperative transferable utility game, we seek welfare distributions that are in the non-cooperative core and satisfy a specific fairness constraint. Meaning, we search for welfare distributions that satisfy all agents’ participation constraints, in that each coalition is at least as well off as it were if acting on its own and that is perceived to be fair, in that no coalition is better off than it were if all non-members of the coalition do not pollute the river at all. We show that the downstream incremental distribution, as introduced by Ambec and Sprumont (2002), is the only welfare distribution satisfying both constraints. In addition, we show that this result holds true for numerous extensions of our model.
In chapter 2, we analyse the contractual mitigation of a global public bad along a river in the presence of a federalist governance structure, where the lower tiers have private information about their abatement costs. We propose that the federal government nominates one of the lower tiers to be the principal, who is authorized to offer mitigation contracts to the other tiers sharing the river. The elected principal can do so either in a centralizedmanner, i.e. he offers contracts simultaneously to all other tiers, or in a delegated manner, i.e. he starts an upstream and downstream sequential contracting process by contracting with his up- and downriver neighbouring tiers, to which he then gives the authority to subcontract with their respective neighbouring tiers till all tiers received a contract. We showthat under certain conditions, a nominated principal can achieve the same abatement allocation with the delegated as with the centralized contracting method while matching his expected costs. As all potential principals implement a different abatement allocation, the choice of the prime principal matters for the total expected costs occurring in the river basin. We show that the tier located most downriver, which is subject to the same informational constraints as the federal government, is never the best choice to be nominated as the principal.
In the third and final chapter, we propose a second-best optimal solution to the problem of pollution abatement in a multi-polluter network with heterogeneously dispersed pollution. Instead of taking an exogenously given and predetermined pollution cap in a cap-and-trade system, the pollution cap is endogenized so that it is determined by the total cost-minimizing equilibrium of a cap-and-trade system. We show that with quadratic abatement costs and linear damage costs, the first-best optimal pollution cap implements the second-best cost-minimizing equilibrium of the cap-and-trade system for any network. However, the second-best optimal abatement allocation differs from the first-best optimal abatement allocation, implying higher second-best optimal total costs than first-best optimal. In particular, second-best optimal total abatement costs fall short of first-best total abatement costs, while second-best optimal total damage costs exceed first-best optimal damage costs. These findings hold for two different cap-and-trade systems considered, the emission permit market and the ambient pollution market
Interpersonale Konsequenzen von offenen Selbstgesprächen in Dyaden im Sport
Full text linkIn der sportpsychologischen Forschung werden sowohl offene als auch verdeckte Selbstgespräche mehrheitlich als rein intrapersonale Phänomene betrachtet und sowohl deren Antezedenzien als auch Konsequenzen nur auf die mit sich selbst sprechende Person bezogen untersucht. Erste laborexperimentelle Studien, die die Effekte von offenen Selbstgesprächen auf die Eindrucksbildung (Graf, Lier & Seiler, 2012; Van Raalte, Brewer, Cornelius & Petitpas, 2006) und die individuelle Leistung (Gould & Weiss, 1981) eines Beobachters nachweisen konnten und Aussagen verschiedener Tennisspieler (Rimmer, Greenlees, Graydon, Thelwell & Buscombe, 2008), dass sie die offene Selbstgespräche der Gegner bei der Bildung eines ersten Eindrucks verwenden würden, deuten jedoch auf die Bedeutsamkeit von interpersonalen Konsequenzen von offenen Selbstgesprächen hin. Um das Verständnis für die interpersonalen Konsequenzen von offenen Selbstgesprächen im Sport zu vertiefen, wurden zwei Studien mit unterschiedlicher Methodik durchgeführt.
In einer qualitativen Feldstudie wurden mit 13 Badmintonspielern im Anschluss an ihr Badminton Herren-Doppel Selbstkonfrontationsinterviews durchgeführt, um die Wahrnehmungsergebnisse nach offenen, während eines realen Wettkampfes geäusserten Selbstgesprächen zu untersuchen. Die wahrgenommenen positiven, negativen und motivierenden Selbstgespräche führten zu Zuschreibungen von mentalen Zuständen und Kognitionen und vereinzelt zur Einschätzung des episodischen Leistungsvermögens. Weiter lösten die Selbstgespräche verschiedene affektive Reaktionen und Erwartungsreaktionen aus, deren mögliche Konsequenzen für den weiteren Spielverlauf diskutiert werden.
Um einzelne Resultate aus dieser ersten Studie eingehender zu analysieren (zugeschriebene Kompetenz und stellvertretende Valenzeinschätzung; Birrer & Seiler, 2008), und zur Untersuchung der Effekte der offenen Selbstgespräche auf die individuelle Leistung eines Teampartners wurde eine zweite, laborexperimentelle Studie durchgeführt. Zur Herstellung der drei experimentellen Bedingungen kam ein gleichgeschlechtlicher Konfident zum Einsatz, der als vermeintlicher Teampartner fungierte und der während der Golf-Putt-Aufgabe als Reaktion auf die eigenen Putts positive, negative oder keine Selbstgespräche führte. Bezogen auf die zugeschriebene Kompetenz zeigte sich kein allgemeiner, sondern ein von der Valenz der Probanden bedingter Effekt der negativen Selbstgespräche: War den Probanden die Aufgabe wichtig, führten negative Selbstgespräche zur Zuschreibung einer tiefen Kompetenz. Weiter lösten sowohl positive als auch negative Selbstgespräche die Einschätzung aus, dass dem Partner die Aufgabe wichtig ist. Keine Effekte hatten die Selbstgespräche auf die individuelle Leistung der Probanden. Explorativ durchgeführte Nachanalysen deuten jedoch darauf hin, dass sich die Selbstgespräche des Partners womöglich nach einer gewissen Zeit auf die individuelle Leistung der wahrnehmenden Person auswirken könnten, weshalb methodische Anpassungen diskutiert werden, mit Hilfe derer der Effekt der Selbstgespräche auf die Leistung gesteigert werden könnte. Neben den hypothesenprüfenden Tests ermittelten verschiedene Post-Hoc-Analysen aufschlussreiche Resulate (z.B. zu affektiven Reaktionen).
Die Ergebnisse der beiden Studien bringen klar zum Ausdruck, dass die interpersonale Perspektive bei der Erforschung der Effekte von offenen Selbstgesprächen bedeutsame Erkenntnisse für Theorie und Praxis liefern kann
A new Time-Of-Flight Mass Spectrometer (TOF-MS) for noble gas analysis
Full text linkNoble gas analysis in early solar system materials, which can provide valuable information about early solar system processes and timescales, are very challenging because of extremely low noble gas concentrations (ppt). We therefore developed a new compact sized (33 cm length, 7.2cm diameter, 1.3 L internal volume) Time-of-Flight (TOF) noble gas mass spectrometer for high sensitivity. We call it as Edel Gas Time-of-flight (EGT) mass spectrometer. The instrument uses electron impact ionization coupled to an ion trap, which allows us to ionize and measure all noble gas isotopes. Using a reflectron set-up improves the mass resolution. In addition, the reflectron set-up also enables some extra focusing. The detection is via MCPs and the signals are processed either via ADC or TDC systems.
The objective of this work is to understand the newly developed Time-Of-Flight (TOF) mass spectrometer for noble gas analysis in presolar grains of the meteorites.
Chapter 1 briefly introduces the basic idea and importance of the instrument. The physics relevant to time-of-flight mass spectrometry technique is discussed in the Chapter 2 and Chapter 3 will present the oxidation technique of nanodiamonds of the presolar grains by using copper oxide. Chapter 4 will present the details about EGT data analysis software. Chapter 5 and Chapter 6 will explain the details about EGT design and operation. Finally, the performance results will be presented and discussed in the Chapter 7, and whole work is summarized in Chapter 8 and also outlook of the future work is given
Finite volume effects in chiral perturbation theory with twisted boundary conditions
Full text linkWe study the effects of a finite cubic volume with twisted boundary conditions on pseudoscalar mesons. We apply Chiral Perturbation Theory in the p-regime and introduce the twist by means of a constant vector field. The corrections of masses, decay constants, pseudoscalar coupling constants and form factors are calculated at next-to-leading order. We detail the derivations and compare with results available in the literature. In some case there is disagreement due to a different treatment of new extra terms generated from the breaking of the cubic invariance. We advocate to treat such terms as renormalization terms of the twisting angles and reabsorb them in the on-shell conditions. We confirm that the corrections of masses, decay constants, pseudoscalar coupling constants are related by means of chiral Ward identities. Furthermore, we show that the matrix elements of the scalar (resp. vector) form factor satisfies the Feynman–Hellman Theorem (resp. the Ward–Takahashi identity). To show the Ward–Takahashi identity we construct an effective field theory for charged pions which is invariant under electromagnetic gauge transformations and which reproduces the results obtained with Chiral Perturbation Theory at a vanishing momentum transfer. This generalizes considerations previously published for periodic boundary conditions to twisted boundary conditions.
Another method to estimate the corrections in finite volume are asymptotic formulae. Asymptotic formulae were introduced by Lüscher and relate the corrections of a given physical quantity to an integral of a specific amplitude, evaluated in infinite volume. Here, we revise the original derivation of Lüscher and generalize it to finite volume with twisted boundary conditions. In some cases, the derivation involves complications due to extra terms generated from the breaking of the cubic invariance. We isolate such terms and treat them as renormalization terms just as done before. In that way, we derive asymptotic formulae for masses, decay constants, pseudoscalar coupling constants and scalar form factors. At the same time, we derive also asymptotic formulae for renormalization terms. We apply all these formulae in combination with Chiral Perturbation Theory and estimate the corrections beyond next-to-leading order. We show that asymptotic formulae for masses, decay constants, pseudoscalar coupling constants are related by means of chiral Ward identities. A similar relation connects in an independent way asymptotic formulae for renormalization terms. We check these relations for charged pions through a direct calculation. To conclude, a numerical analysis quantifies the importance of finite volume corrections at next-to-leading order and beyond. We perform a generic Analysis and illustrate two possible applications to real simulations
Code-switching: a touchstone of models of bilingual language production
Full text linkThe goal of the present thesis was to investigate the production of code-switched utterances in bilinguals’ speech production. This study investigates the availability of grammatical-category information during bilingual language processing. The specific aim is to examine the processes involved in the production of Persian-English bilingual compound verbs (BCVs). A bilingual compound verb is formed when the nominal constituent of a compound verb is replaced by an item from the other language. In the present cases of BCVs the nominal constituents are replaced by a verb from the other language. The main question addressed is how a lexical element corresponding to a verb node can be placed in a slot that corresponds to a noun lemma. This study also investigates how the production of BCVs might be captured within a model of BCVs and how such a model may be integrated within incremental network models of speech production. In the present study, both naturalistic and experimental data were used to investigate the processes involved in the production of BCVs. In the first part of the present study, I collected 2298 minutes of a popular Iranian TV program and found 962 code-switched utterances. In 83 (8%) of the switched cases, insertions occurred within the Persian compound verb structure, hence, resulting in BCVs. As to the second part of my work, a picture-word interference experiment was conducted. This study addressed whether in the case of the production of Persian-English BCVs, English verbs compete with the corresponding Persian compound verbs as a whole, or whether English verbs compete with the nominal constituents of Persian compound verbs only. Persian-English bilinguals named pictures depicting actions in 4 conditions in Persian (L1). In condition 1, participants named pictures of action using the whole Persian compound verb in the context of its English equivalent distractor verb. In condition 2, only the nominal constituent was produced in the presence of the light verb of the target Persian compound verb and in the context of a semantically closely related English distractor verb. In condition 3, the whole Persian compound verb was produced in the context of a semantically unrelated English distractor verb. In condition 4, only the nominal constituent was produced in the presence of the light verb of the target Persian compound verb and in the context of a semantically unrelated English distractor verb. The main effect of linguistic unit was significant by participants and items. Naming latencies were longer in the nominal linguistic unit compared to the compound verb (CV) linguistic unit. That is, participants were slower to produce the nominal constituent of compound verbs in the context of a semantically closely related English distractor verb compared to producing the whole compound verbs in the context of a semantically closely related English distractor verb. The three-way interaction between version of the experiment (CV and nominal versions), linguistic unit (nominal and CV linguistic units), and relation (semantically related and unrelated distractor words) was significant by participants. In both versions, naming latencies were longer in the semantically related nominal linguistic unit compared to the response latencies in the semantically related CV linguistic unit. In both versions, naming latencies were longer in the semantically related nominal linguistic unit compared to response latencies in the semantically unrelated nominal linguistic unit. Both the analysis of the naturalistic data and the results of the experiment revealed that in the case of the production of the nominal constituent of BCVs, a verb from the other language may compete with a noun from the base language, suggesting that grammatical category does not necessarily provide a constraint on lexical access during the production of the nominal constituent of BCVs. There was a minimal context in condition 2 (the nominal linguistic unit) in which the nominal constituent was produced in the presence of its corresponding light verb. The results suggest that generating words within a context may not guarantee that the effect of grammatical class becomes available. A model is proposed in order to characterize the processes involved in the production of BCVs. Implications for models of bilingual language production are discussed
Computational Tools for Stereo and Light Field Photography
Full text linkThis thesis covers a broad part of the field of computational photography, including video stabilization and image warping techniques, introductions to light field photography and the conversion of monocular images and videos into stereoscopic 3D content. We present a user assisted technique for stereoscopic 3D conversion from 2D images. Our approach exploits the geometric structure of perspective images including vanishing points. We allow a user to indicate lines, planes, and vanishing points in the input image, and directly employ these as guides of an image warp that produces a stereo image pair. Our method is most suitable for scenes with large scale structures such as buildings and is able to skip the step of constructing a depth map. Further, we propose a method to acquire 3D light fields using a hand-held camera, and describe several computational photography applications facilitated by our approach. As the input we take an image sequence from a camera translating along an approximately linear path with limited camera rotations. Users can acquire such data easily in a few seconds by moving a hand-held camera. We convert the input into a regularly sampled 3D light field by resampling and aligning them in the spatio-temporal domain. We also present a novel technique for high-quality disparity estimation from light fields. Finally, we show applications including digital refocusing and synthetic aperture blur, foreground removal, selective colorization, and others
A database framework to incorporate statistical variability in biomechanical simulations
Full text linkDevelopment and Evaluation of a New Tablet Computer Application for the Therapy of Brain-Injured Patients with Aphasia
Full text linkIntroduction
Language is the most important mean of communication and plays a central role in our everyday life. Brain damage (e.g. stroke) can lead to acquired disorders of lan- guage affecting the four linguistic modalities (i.e. reading, writing, speech production and comprehension) in different combinations and levels of severity. Every year, more than 5000 people (Aphasie Suisse) are affected by aphasia in Switzerland alone. Since aphasia is highly individual, the level of difficulty and the content of tasks have to be adapted continuously by the speech therapists. Computer-based assignments allow patients to train independently at home and thus increasing the frequency of ther- apy. Recent developments in tablet computers have opened new opportunities to use these devices for rehabilitation purposes. Especially older people, who have no prior experience with computers, can benefit from the new technologies.
Methods
The aim of this project was to develop an application that enables patients to train language related tasks autonomously and, on the other hand, allows speech therapists to assign exercises to the patients and to track their results online. Seven categories with various types of assignments were implemented. The application has two parts which are separated by a user management system into a patient interface and a therapist interface. Both interfaces were evaluated using the SUS (Subject Usability Scale). The patient interface was tested by 15 healthy controls and 5 patients. For the patients, we also collected tracking data for further analysis. The therapist interface was evaluated by 5 speech therapists.
Results
The SUS score are xpatients = 98 and xhealthy = 92.7 (median = 95, SD = 7, 95% CI [88.8, 96.6]) in case of the patient interface and xtherapists = 68 in case of the therapist interface.
Conclusion
Both, the patients and the healthy subjects, attested high SUS scores to the patient interface. These scores are considered as "best imaginable". The therapist interface got a lower SUS score compared to the patient interface, but is still considered as "good" and "usable". The user tracking system and the interviews revealed that there is room for improvements and inspired new ideas for future versions
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