This thesis deals with the subject of proving negatives, i. e. proving non-existence of an object, a status or a process. The author of the thesis provides the reader with the definition of a negative and with a list of negatives mentioned in the case law of Czech public authorities. Also, the author analyses selected case law of Czech courts and describes proving negatives in specific cases. The thesis is divided into six chapters. The first chapter provides the definition of a negative. In this chapter the author points out potential problems linked to the identification of a negative, especially to the difference between a fact, a negative statement and a legal assessment. The second one addresses the possibility of a negative becoming the subject of proving as a practical way of finding of facts. The chapter also brings a brief analysis of proving a negative abroad, specifically in Slovakia, the Great Britain and the United States of America. The third, the fourth and the fifth chapter deal with the subject of proving negatives in civil proceedings, administrative proceedings and criminal proceedings respectively. In each of these chapters the author summarises the principles of proving related to corresponding type of proceedings and demonstrates proving negatives on specific cases (regarding...

The purpose of this experimental study is to examine the effects of recasts on narrowing overgeneralized grammar in the second language (L2). The study involved testing three major hypotheses of the mechanisms underlying recasts: the direct contrast hypothesis (Saxton, 1997, 2000), the additional input hypothesis (Gass, 1997; Gass & Mackey, 2007; Long, 1996, 2007), and the enhanced salience hypothesis (Leeman, 2003). Two structures (adjective ordering and indirect passives) were selected for this study, mainly because it was assumed that Japanese learners of English might produce overgeneralized rules that allow incorrect structures because of their first language (L1) influence. The participants were 97 Japanese university students learning English as a foreign language in Japan. They were randomly assigned to four treatment groups: recast (the REC Group), non-contingent positive evidence (the POS Group), recast plus additional input (the REC+ Group), and input with enhanced salience (the SAL Group). A pretest, posttest, and delayed-posttest design were employed. The measurement instruments were an oral production task, elicited imitation task, and untimed grammaticality judgment task, each of which was designed to elicit participants’ implicit and explicit knowledge about adjective ordering and indirect passives. Thus, the independent variable was the treatment conditions, and the dependent variable were the test scores regarding ungrammaticality of the overgeneralized rules of the target structures. After data screening, the data from 75 of the 97 participants were analyzed for adjective ordering, and the data from 90 participants were analyzed for indirect passives. The results showed that the POS Group did not improve on all the measures for adjective ordering and indirect passives; thus, it was suggested that positive evidence was not sufficient for the participants to narrow overgeneralized rules for the target structures. The findings indicated that for adjective ordering, medium effect sizes for the comparison of the POS and REC Groups were obtained on the grammaticality judgment tests for the pretest-posttest and pretest-delayed posttest comparisons. Thus, based on these effect sizes, the direct contrast hypothesis was partially supported (i.e., for one of the two structures and one measure of the three tests). Furthermore, on the basis of the results that the REC and REC+ Groups did not differ significantly on any measure and that on the adjective-ordering grammaticality judgment tests, the comparison between the REC+ Group and the POS Group obtained a medium effect size for the pretest-delayed posttest comparison, the provision of recasts in the REC and REC+ Groups was effective at least for the adjective-ordering grammaticality judgment tests; however, additional input alone did not have an impact on L2 learners’ retreat from the overgeneralized rules. Finally, the results showed that the POS and SAL Groups did not differ significantly and that there existed a difference in the performance on the adjective-ordering grammaticality judgment tests between the REC Group and the SAL Groups. Salience might not be effective in helping L2 learners retreat from overgeneralized rules, and the enhanced salience hypothesis can be interpreted as being limited to learning some linguistic structures. In conclusion, the present study provides empirical evidence that L2 learners can persist in using incorrect overgeneralized rules due to L1 rules and that ten tokens of the target structures are not effective for L2 learners to retreat from the overgeneralized rules. Furthermore, the findings lend support to the direct contrast hypothesis as a mechanism underlying recasts for one of the two target structures. / Teaching & Learning

Trotz der Entwicklungen der letzten Jahre kommt es in der Robotik immer noch vor, dass mobile Roboter scheinbar sinnlose Handlungen ausführen. Der Grund für dieses Verhalten ist oftmals, dass sich das interne Weltbild des Roboters stark von der tatsächlichen Situation, in der sich der Roboter befindet, unterscheidet. Die darauf basierende Robotersteuerung wählt infolge dieser Diskrepanz scheinbar sinnlose Handlungen aus. Eine wichtige Ursache von Lokalisierungsfehlern stellen Kollisionen des Roboters mit anderen Robotern oder seiner Umwelt dar. Mit Hilfe eines Hindernismodells wird der Roboter in die Lage versetzt, Hindernisse zu erkennen, sich ihre Position zu merken und Kollisionen zu vermeiden. Ferner wird in dieser Arbeit eine Erweiterung der Bewegungsmodellierung beschrieben, die die Bewegung in Mobilitätszustände untergliedert, die jeweils ein eigenes Bewegungsmodell besitzen und die mit Hilfe von Propriozeption unterschieden werden können. Mit Hilfe der Servo-Motoren des Roboters lässt sich eine Art Propriozeption erzielen: der momentan gewünschte, angesteuerte Gelenkwinkel wird mit dem tatsächlich erreichten, im Servo-Motor gemessenen Winkel verglichen. Dieser "Sinn" erlaubt eine bessere Beschreibung der Roboterbewegung. Verbesserung des Sensormodells wird das bisher wenig untersuchte Konzept der Negativinformation, d.h. das Ausbleiben einer erwarteten Messung, genutzt. Bestehende Lokalisierungsansätze nutzen diese Information nicht, da es viele Gründe für ein Ausbleiben einer erwarteten Messung gibt. Eine genaue Modellierung des Sensors ermöglicht es jedoch, Negativinformation nutzbar zu machen. Eine Weltmodellierung, die Negativinformation verarbeiten kann, ermöglicht eine Lokalisierung des Roboters in Situationen, in denen einzig auf Landmarken basierende Ansätze scheitern. / Despite the dramatic advancements in the field of robotics, robots still tend to exhibit erratic behavior when facing unexpected situations, causing them, for example, to run into walls. This is mainly the result of the robot''s internal world model no longer being an accurate description of the environment and the robot''s localization within the environment. The key challenge explored in this dissertation is the creation of an internal world model for mobile robots that is more robust and accurate in situations where existing approaches exhibit a tendency to fail. First, means to avoid a major source of localization error - collisions - are investigated. Efficient collision avoidance is achieved by creating a model of free space in the direct vicinity of the robot. The model is based on camera images and serves as a short term memory, enabling the robot to avoid obstacles that are out of sight. It allows the robot to efficiently circumnavigate obstacles. The motion model of the robot is enhanced by integrating proprioceptive information. Since the robot lacks sensors dedicated to proprioception, information about the current state and configuration of the robot''s body is generated by comparing control commands and actual motion of individual joints. This enables the robot to detect collisions with other robots or obstacles and is used as additional information for modeling locomotion. In the context of sensing, the notion of negative information is introduced. Negative information marks the ascertained absence of an expected observation in feature-based localization. This information is not used in previous work on localization because of the several reasons for a sensor to miss a feature, even if the object lies within its sensing range. This information can, however, be put to good use by carefully modeling the sensor. Integrating negative information allows the robot to localize in situations where it cannot do so based on landmark observation alone.

Cette thèse a pour objectif d’étudier certains aspects du traitement et de l’acquisition de la morphologie verbale du russe. Le but de ce travail est double. Premièrement, nous avons étudié le traitement d’une alternance consonantique, la palatalisation, par des adultes russophones. Ce processus morphonologique mène à l’allomorphie des radicaux dans plusieurs classes verbales dont les verbes subissent la surgénéralisation dans le langage des enfants. Deuxièmement, nous avons testé l’effet de la rétroaction négative présentée dans l’input, surtout l’effet durable, sur l’élimination des erreurs de surgénéralisation fréquentes chez les enfants en russe. Dans la première étude, nous présentons des données expérimentales sur le traitement des emprunts et des non-mots. Plus particulièrement, cette étude vise à répondre à la question de savoir comment la palatalisation de consonnes dentales et vélaires est traitée par des locuteurs adultes du russe. Les résultats montrent que la palatalisation est semi-productive en fonction des facteurs suivants: a) la distribution des allomorphes à l’intérieur du paradigme, et b) la productivité des classes verbales. Nous supposons que la différence dans le traitement de la palatalisation chez les adultes devrait être reflétée dans le langage des enfants. Notre deuxième article présente les résultats de l’étude sur les effets de la rétroaction négative dans l’acquisition de la morphologie flexionnelle en russe. Pour ce faire nous avons mené une série de tâches induites auprès d’enfants russophones âgés de 3 à 4 ans. Des verbes sensibles à la surgénéralisation en yod /j/, une erreur typique des enfants de cet âge, ont été utilisés comme stimuli. Les participants ont été divisés en quatre groupes selon le type de rétroaction (correction, question de clarification et répétition) auquel ils étaient exposés. Dans chaque groupe de participants, nous avons observé une amélioration significative en production cible de formes verbales avec le temps. Cependant aucune différence significative n’a été trouvée concernant le type de rétroaction. Ces résultats suggèrent que la rétroaction négative ne joue pas un rôle important dans le processus d’acquisition. Ensemble, les deux études représentent une nouvelle contribution à la discussion sur les processus irréguliers en morphologie et le phénomène de surgénéralisation, ainsi que sur le (non) rôle de la rétroaction dans l’élimination des formes surgénéralisées dans le langage des enfants. / This thesis aims at studying certain aspects of Russian verb morphology processing and acquisition. The goal was two-fold: first, we investigated the productivity of morphonological alternations that lead to irregular verb stem allomorphy among adult speakers of Russian. The verbs in the study are known to undergo overregularization in Russian child speech. Second, we tested the (potentially) lasting effect of negative feedback on the retreat from overregularization errors in children. In the first paper, we present experimental data on the processing of loanwords and nonce words that focus on a morphonological alternation (palatalization) in Russian. This study addresses the issue of how stem allomorphy involving palatalization of the velar/palatal and dental/palatal types in the Russian verb system is processed by adults. Processing of palatalization is shown to be quite variable and to depend on: (i) different distribution of allomorphs (past/non-past or 1Sg./other forms) within the verb paradigm, and (ii) overall productivity of verbal classes. We also hypothesized that these differences should be reflected in child language verb morphology acquisition. The study presented in the second article investigates negative feedback effects on inflectional morphology acquisition in Russian. With that goal in mind, we conducted a series of elicited tasks with Russian speaking children aged from 3 to 4 years. Verbs which undergo overregularization in the non-past tense resulting from applying the yod /j/-pattern (typical errors for children of this age) were used as stimuli. Four groups of participants were formed accordingly to three types of feedback (Correction, Clarification question and Repetition), and a control group without feedback. Our results revealed a significant effect of time on target verb form production. However, no significant difference was observed as a function of feedback type, or even where there was no feedback. This finding supports the general hypothesis that negative feedback is not an important factor of language acquisition. Altogether, the results presented in this thesis provide new insights on irregular processes in Russian verb morphology, as well as on the inefficiency of negative feedback in the acquisition of L1 morphology.

This study investigates second language (L2) acquisition of word orders and markers of collectivity in Chinese and Thai. One of the differences between Chinese and Thai is that Chinese nominal phrases appear with a “numeral + classifier + noun” word order while Thai phrases appear as “noun + numeral + classifier”. Another difference is that men, the Chinese collective marker, cannot be used with nouns referring to animals or indefinite nouns, while phûak, the Thai collective marker, can do so. Based on the cross-linguistic differences, an empirical study was conducted to answer whether Thai learners of Chinese and Chinese learners of Thai would be able to acquire target language (TL) structures that are different from those in their native language (L1) and whether they could reject incorrect TL structures. One hundred and forty-four participants were recruited to complete an acceptability judgment task and a self-paced reading task. It is found that both Chinese and Thai learners could perform native-like in their acceptance of TL word orders since early stages of acquisition. However, it took them until an advanced level to be able to completely reject incorrect TL word orders that resembled structures in their L1. Thai learners also faced difficulty rejecting the use of men with animal and indefinite nouns in their L2 Chinese. In contrast, Chinese learners tended to be successful in their acquisition of phûak. The results are interpreted in terms of roles of positive evidence and form-function transparency. In general, L2 learners tend to acquire a TL structure earlier when they can receive positive evidence in TL input and when a form-function connection of the structure is transparent. Nonetheless, these factors do not have an absolute effect on acquisition outcome since some learners may be able to use a probabilistic learning strategy to successfully acquire L2 knowledge even when positive evidence is unavailable.