In this thesis work we present CLIK, a new, automated, remote attack on the control logic of a programmable logic controller (PLC) in industrial control systems. The CLIK attack modifies the control logic running in a remote target PLC automatically to disrupt a physical process. We implement the CLIK attack on a real PLC. The attack is initiated by subverting the security measures that protect the control logic in a PLC. We found a critical (zero-day) vulnerability, which allows the attacker to overwrite password hash in the PLC during the authentication process. Next, CLIK retrieves and decompiles the original logic and injects a malicious logic into it and then, transfers the infected logic back to the PLC. To hide the infection, we propose a virtual PLC that engages the software the virtual PLC intercepts the request and then, responds with the original (uninfected) control logic to the software.

At California State University San Bernardino, students can ordinarily register online and join waiting lists when a course is full. However, the system does not support waiting lists when a course has associated laboratory sections. This project addresses this problem.

The aim of this thesis was to prepare, implement and evaluate an excursion as one of the organization forms of fieldtrips for lower secondary pupils from schools in Znojmo benefiting from the natural site of the National Park Podyjí, in specific the location called Kraví hora. In this case, it is a botanical the med field trip. The theoretical part of the thesis deals with general characteristics of the National Park Podyjí from various nature views highlighting its specially protected areas. This is followed by a description of specific field trip aspects and the most frequently used teaching methods together. The practical part contains, among other things, methodological instructions for teachers and pupils as well as didactic materials (worksheets, didactic test), included in the appendix. Questionnaire surveys for pupils and teachers are part of the last empirical chapter. The aim of the questionnaire was to record and evaluate thoughts, feelings and attitudes of pupils from the lower secondary school to the specific field trip, its implementation and overall organization. The aim of subsequently submitted didactic tests was to observe and reveal the effectiveness of the field trip teaching. The aim of the questionnaire, given to teachers, was to monitor their standpoints in relation to...

Overlearning is defined as the continued study of an item immediately after it has been correctly recalled once. Based on past studies, the effectiveness of overlearning is uncertain. In the present study, the effectiveness of overlearning was tested in 3 experiments. In Experiment 1, participants studied 10 city-country pairs (e.g. doba, chad) to either a low or high degree of learning and were tested 1, 3, or 9 weeks later. In Experiments 2 and 3, participants studied varying numbers of word-definition pairs (e.g. vizard, mask) for a constant total study time. They were tested between 1 and 4 weeks later. While overlearning improved test performance, this difference in recall diminished at longer retention intervals. Furthermore, overlearning was found to be inefficient because the increase in recall was not proportional to the increase in study time. Finally, for a given amount of study time, the underlearning of more words led to higher absolute recall totals than did the overlearning of fewer words.

<p>The purpose of this report is to implement and evaluate parts of the simulation software used in the SoCBUS project. In order to complete and evaluate the entire software package, a traffic model and a stimuli generator must be implemented. They are implemented and evaluated together with the entire simulator software. The purpose of the Traffic model is to model communication traffic as good and descriptive as possible. The output of the Traffic model is called a test case, which works as input for the Stimuli generator. The Stimuli generator computes and creates an event list for the Simulator. This report will investigate and motivate the presented traffic model and stimuli generator in detail. The simulator software is then tested with two separate test cases in order to investigate if the simulator software works properly. The results are promising and the simulator software behaves as expected.</p>

<p>This paper studies the philosopher Ludwig Wittgenstein during his years (1920–26) as an elementary school teacher in remote Niederösterreich, Austria. The paper gives a survey of his life, and also a brief account of three of his main works: Tractatus Logico-Philosophicus, Philosophical Investigations and Remarks on the Foundations of Mathematics. Attention is given to his alphabetical word list, Wörterbuch für Volksschulen, published for educational use in elementary schools. The study is focused on Wittgenstein’s educational practise, and establishes a connection between his experience as a teacher and his late philosophy.</p>

This paper studies the philosopher Ludwig Wittgenstein during his years (1920–26) as an elementary school teacher in remote Niederösterreich, Austria. The paper gives a survey of his life, and also a brief account of three of his main works: Tractatus Logico-Philosophicus, Philosophical Investigations and Remarks on the Foundations of Mathematics. Attention is given to his alphabetical word list, Wörterbuch für Volksschulen, published for educational use in elementary schools. The study is focused on Wittgenstein’s educational practise, and establishes a connection between his experience as a teacher and his late philosophy.

The purpose of the present study is (1) to investigate factors that influence mathematical problem solving competence for elementary students, (2) to understand the current studies regarding the development of mathematical problem solving competence, and (3) to probe background factors that affect the development of mathematical problem solving competence. The subjects of the study included 710 fifth-graders in Tainan city. The surveys of Thinking Style Inventory, Mathematical Learning Perception Check List as well as Mathematical Problem Solving Competence Test were used as instruments for data collection. A total of 710 questionnaires were delivered and 587valid questionnaires were collected, with fairly high 82.60% return rate. The collected data was tested with descriptive analysis, independent t test¡BANOVA¡Bproduct-moment correlation coefficient,multiple correlation and multiple regression. Based on the data analysis, the six findings of this study are summarized as follows: 1. The low satisfaction with mathematics class was revealed from the analysis of students¡¦ Mathematical Learning Perception Check List. It is suggested boosting subjects¡¦ satisfaction with the mathematics class will enhance the development of mathematical problem solving competence. 2. The positive correlation between administration style and mathematical problem solving competence was shown eminently among all types of thinking styles. The result indicated different function of the thinking styles influenced the development of mathematical problem solving competence in a varied degree. 3. From the analysis of students¡¦ background factor and mathematics problem solving competence, the statistic indicated the length of extra curriculum students devoted to does not affect their mathematical problem solving competence. The factors that influence students¡¦ mathematical problem solving competence the most were shown in the following order: administration district, the social status of father, the social status of mother, gender and the size of school. 4. The comparative variance of the mathematics learning achievement and mathematics problem solving competence was 24.3%. It implied the two influences each other. Students with low mathematical learning achievement show low mathematical problem solving competence and vice versa. 5. When predicting students¡¦ development of mathematical problem solving competence via the data of parents¡¦ social status and mathematical learning perception check list, the result showed the prediction via parents¡¦ social status is less significant. Yet the prediction via mathematical learning perception check list gained the highest variance ratio in this case. 6. In terms of the distribution of parents¡¦ social status, East, North and Middle East were of eminent as compared to South, An-Ping and An-Nan district in Tainan city. The finding implied parents¡¦ social status was a major factor that influence students¡¦ mathematics problem solving ability in administration district, as the £b2 ¡]Eta Squared¡^¡×25.3¢H shown in this study.

We study several extremal problems in graphs and hypergraphs. The first one is on list-colouring hypergraphs, which is a generalization of the ordinary colouring of hypergraphs. We discuss two methods for determining the list-chromatic number of hypergraphs. One method uses hypergraph polynomials, which invokes Alon's combinatorial nullstellensatz. This method usually requires computer power to complete the calculations needed for even a modest-sized hypergraph. The other method is elementary, and uses the idea of minimum improper colourings. We apply these methods to various classes of hypergraphs, including the projective planes. We focus on solving the list-colouring problem for Steiner triple systems (STS). It is not hard using either method to determine that Steiner triple systems of orders 7, 9 and 13 are 3-list-chromatic. For systems of order 15, we show that they are 4-list-colourable, but they are also ``almost'' 3-list-colourable. For all Steiner triple systems, we prove a couple of simple upper bounds on their list-chromatic numbers. Also, unlike ordinary colouring where a 3-chromatic STS exists for each admissible order, we prove using probabilistic methods that for every $s$, every STS of high enough order is not $s$-list-colourable. The second problem is on embedding nearly-spanning bounded-degree trees in sparse graphs. We determine sufficient conditions based on expansion properties for a sparse graph to embed every nearly-spanning tree of bounded degree. We then apply this to random graphs, addressing a question of Alon, Krivelevich and Sudakov, and determine a probability $p$ where the random graph $G_{n,p}$ asymptotically almost surely contains every tree of bounded degree. This $p$ is nearly optimal in terms of the maximum degree of the trees that we embed. Finally, we solve a problem that arises from quantum computing, which can be formulated as an extremal question about maximizing the size of a type of acyclic directed graph.

In this thesis we introduce and evaluate several new models for the analysis of online algorithms. In an online problem, the algorithm does not know the entire input from the beginning; the input is revealed in a sequence of steps. At each step the algorithm should make its decisions based on the past and without any knowledge about the future. Many important real-life problems such as paging and routing are intrinsically online and thus the design and analysis of online algorithms is one of the main research areas in theoretical computer science. Competitive analysis is the standard measure for analysis of online algorithms. It has been applied to many online problems in diverse areas ranging from robot navigation, to network routing, to scheduling, to online graph coloring. While in several instances competitive analysis gives satisfactory results, for certain problems it results in unrealistically pessimistic ratios and/or fails to distinguish between algorithms that have vastly differing performance under any practical characterization. Addressing these shortcomings has been the subject of intense research by many of the best minds in the field. In this thesis, building upon recent advances of others we introduce some new models for analysis of online algorithms, namely Bijective Analysis, Average Analysis, Parameterized Analysis, and Relative Interval Analysis. We show that they lead to good results when applied to paging and list update algorithms. Paging and list update are two well known online problems. Paging is one of the main examples of poor behavior of competitive analysis. We show that LRU is the unique optimal online paging algorithm according to Average Analysis on sequences with locality of reference. Recall that in practice input sequences for paging have high locality of reference. It has been empirically long established that LRU is the best paging algorithm. Yet, Average Analysis is the first model that gives strict separation of LRU from all other online paging algorithms, thus solving a long standing open problem. We prove a similar result for the optimality of MTF for list update on sequences with locality of reference. A technique for the analysis of online algorithms has to be effective to be useful in day-to-day analysis of algorithms. While Bijective and Average Analysis succeed at providing fine separation, their application can be, at times, cumbersome. Thus we apply a parameterized or adaptive analysis framework to online algorithms. We show that this framework is effective, can be applied more easily to a larger family of problems and leads to finer analysis than the competitive ratio. The conceptual innovation of parameterizing the performance of an algorithm by something other than the input size was first introduced over three decades ago [124, 125]. By now it has been extensively studied and understood in the context of adaptive analysis (for problems in P) and parameterized algorithms (for NP-hard problems), yet to our knowledge this thesis is the first systematic application of this technique to the study of online algorithms. Interestingly, competitive analysis can be recast as a particular form of parameterized analysis in which the performance of opt is the parameter. In general, for each problem we can choose the parameter/measure that best reflects the difficulty of the input. We show that in many instances the performance of opt on a sequence is a coarse approximation of the difficulty or complexity of a given input sequence. Using a finer, more natural measure we can separate paging and list update algorithms which were otherwise indistinguishable under the classical model. This creates a performance hierarchy of algorithms which better reflects the intuitive relative strengths between them. Lastly, we show that, surprisingly, certain randomized algorithms which are superior to MTF in the classical model are not so in the parameterized case, which matches experimental results. We test list update algorithms in the context of a data compression problem known to have locality of reference. Our experiments show MTF outperforms other list update algorithms in practice after BWT. This is consistent with the intuition that BWT increases locality of reference.