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No description available.

Most of the recent efficient algorithms for dependency parsing work by factoring the dependency trees. In most of these approaches, the parser loses much of the contextual information during the process of factorization. There have been approaches to build higher order dependency parsers - second order, [Carreras2007] and third order [Koo and Collins2010]. In the thesis, the approach by Koo and Collins should be further exploited in one or more ways. Possible directions of further exploitation include but are not limited to: investigating possibilities of extension of the approach to non-projective parsing; integrating labeled parsing; joining word-senses during the parsing phase [Eisner2000]

Most of the recent efficient algorithms for dependency parsing work by factoring the dependency trees. In most of these approaches, the parser loses much of the contextual information during the process of factorization. There have been approaches to build higher order dependency parsers - second order, [Carreras2007] and third order [Koo and Collins2010]. In the thesis, the approach by Koo and Collins should be further exploited in one or more ways. Possible directions of further exploitation include but are not limited to: investigating possibilities of extension of the approach to non-projective parsing; integrating labeled parsing; joining word-senses during the parsing phase [Eisner2000].

Classical elasticity cannot be used to explain effects related to material microstructures due to its lack of a material length scale parameter. To mitigate this deficiency, higher order elasticity theories have been developed. Two simple higher order theories and their applications are studied in this research. One is a modified couple stress theory and the other is a simplified strain gradient theory, each of which contains only one material length scale parameter in addition to the classical elastic constants. Variational formulations are provided for these two theories by using the principle of minimum total potential energy. In both cases, the governing equations and complete boundary conditions are determined simultaneously for the first time. Also, the displacement form is explicitly derived for each theory for the first time. The modified couple stress theory is applied to solve a simple shear problem, to develop a new Bernoulli-Euler beam model, and to derive the constitutive relations for hexagonal honeycomb structures, while the simplified strain gradient theory is used to solve the pressurized thick-walled cylinder problem. All these models/solutions are obtained for the first time and supplement their counterparts in classical elasticity. Numerical results obtained from the newly developed models and derived solutions and their comparisons with their counterpart results in classical elasticity reveal that the higher order theory based models and solutions have the capacity to account for microstructural effects; their counterparts in classical elasticity do not have the same capability. Nevertheless, the former are shown to recover the latter if the microstructural effects are suppressed or ignored.

In this thesis, we explain the term CCZ-equivalence in more detail to- gether with an analysis of a special type of matrices of this equivalence. We also clarify the higher order differential cryptanalysis and its generalized ver- sion. To demonstrate this method we present several attacks on a simple five round Feistel cipher, two of these attacks are our own. We have implemented the most important attacks and results of these experiments can be found in the text. We also explore how to use a decomposition F = F2 ◦F−1 1 (where F1 and F2 are permutations) to construct a generalized higher order differential attack to a block cipher with an S-box F. This construction may be used while searching for an attack to F using the CCZ-equivalence which is gener- ally a hard question. The result of our research is a theorem which presents a necessary condition on a degree of F which is needed for an existence of such a decomposition. 1

The importance of the electric power infrastructure has been exposed by several blackouts throughout the world in the last decade. These blackouts were caused mainly by physical vulnerabilities, human errors and natural disasters. The power grid is becoming more and more prone to outages which affect not only the power system network, but also other infrastructures and the society in several ways. Utilities generally operate with an (N-1) security level (no violations for single outage), and blackouts are generally caused by higher order contingencies. There is lack of effective methods and analysis tools to deal with higher order contingencies. Higher order contingences include multiple line outages, multiple generator outages or a combination of both. This research work focuses on developing tools to take corrective actions based on sensitivity for these multiple outages. Algorithms developed are Multiple Line Outage Bus Sensitivity Factor (MLOBSF), Multiple Line Outage Voltage Sensitivity (MLOVS), Multiple Generator Outage Bus Sensitivity Factor (MGOBSF) and Multiple Generator Outage Voltage Sensitivity (MGOVS) algorithms based on DC and AC load flow models. These developed algorithms provide the impact on the system due to multiple contingencies and help the operator at the control center to take corrective actions in a quick and effective way. These developed algorithms were tested on three test systems; the six buses, thirty seven buses and the 137 buses actual utility test case. The test results demonstrate that given situational awareness the algorithms provide additional decision support that can be used for remedial actions and/or for recovery after an outage. Integrating these into a power system energy management system (EMS) will provide a tool for operators to have a better understanding of the system before and during an extreme condition.

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In recent years, symbolic and constraint-solving techniques have been making major advances and are continually being deployed in new business and engineering applications. A major push behind this trend has been the development and deployment of sophisticated methods that are able to comprehend and evaluate important sub-classes of symbolic problems (such as those in polynomial, linear inequality and finite domains). However, relatively little has been explored in higher-order domains, such as equations with unknown functions. This paper proposes a new symbolic method for solving a class of higher-order equations with an unknown function over the complex domain. Our method exploits the closure property of group structure (for functions) in order to allow an equivalent system of equations to be expressed and solved in the first-order setting. Our work is an initial step towards the relatively unexplored realm of higher-order constraint-solving, in general; and higher-order equational solving, in particular. We shall provide some theoretical background for the proposed method, and also prototype an implementation under Mathematica. We hope that our foray will help open up more sophisticated applications, as well as encourage work towards new methods for solving higher-order constraints. / Singapore-MIT Alliance (SMA)

Telomeres are specialized nucleoprotein structures found at the end of eukaryotic chromosomes. The telomere DNA in humans is composed of the sequence "5'-TTAGGG-3'" tandemly repeated in a stretch of 5-30kb of double stranded DNA. TTAGGG Repeat Factor 2 (TRF2) is a telomere DNA binding protein that has a critical role in telomere end protection. The current model for telomere protection by TRF2 is through its ability to remodel telomeres into looped higher-order structures, called the t-loop, which sequesters the end from DNA damage sensors. Since telomeres are known to be comprised of nucleosomal chromatin, it is important to determine how TRF2 binds to and affects the structure of nucleosomal arrays. The ability of TRF2 to bind to unusual DNA structures such as the t-loop and the single stranded/double (ss/ds) stranded telomere DNA junction may facilitate its binding to DNA in the form of nucleosomal arrays and promote higher-order chromatin structures. In this study, we have reconstituted a 2kb DNA fragment containing 550bp of telomere DNA into nucleosomal arrays and tested the binding of full-lengthTRF2 and four truncation mutants to telomeric nucleosomal arrays. Our data indicates that TRF2 and its truncation mutants bind to telomere nucleosomal arrays as well as it binds to telomere DNA. We used a novel electrophoretic technique, Analytical Agarose Gel Electrophoresis (AAGE), to measure changes in surface charge density, hydrodynamic radius, and conformational flexibility of DNA and nucleosomal arrays upon protein binding. Our results indicate that the C-terminal DNA binding Myb/SANT domain of TRF2 might be rearranging nucleosomal structure through either nucleosome sliding, unwrapping, or changing the arrangement of the linker DNA, while the N-terminal basic DNA binding region is causing nucleosomal arrays compaction. Instead of significant compaction, histone-free DNA undergoes DNA condensation and self-association. This activity is observed with the full-length protein and all regions of the protein, with the exception of TRF2-DBD, participate in the process. We speculate that the ability of TRF2-DBD to rearrange nucleosomal structure and N-terminal basic region to cause nucleosomal fiber compaction may allow TRF2 to promote t-loop formation in the context of chromatin. We propose that TRF2, possessing all the features, has a new role at telomeres as a chromatin architectural protein.