Concept discovery is the problem of finding definitions of target relation in terms or other relation given as a background knowledge. Inductive Logic Programming (ILP)-based and graph-based approaches are two competitors in concept discovery problem. Although ILP-based systems have long dominated the area, graph-based systems have recently gained popularity as they overcome certain shortcomings of ILP-based systems. While having applications in numerous domains, ILP-based concept discovery systems still sustain scalability and efficiency issues. These issues generally arose due to the large search spaces such systems build. In this work we propose memoization-based and parallelization-based methods that modify the search space construction step and the evaluation step of ILP-based concept discovery systems to overcome these problem. In this work we propose three memoization-based methods, called Tabular CRIS, Tabular CRIS-wEF, and Selective Tabular CRIS. In these methods, basically, evaluation queries are stored in look-up tables for later uses. While preserving some core functions in common, each proposed method improves e_ciency and scalability of its predecessor by introducing constraints on what kind of evaluation queries to store in look-up tables and for how long. The proposed parallelization method, called pCRIS, parallelizes the search space construction and evaluation steps of ILP-based concept discovery systems in a data-parallel manner. The proposed method introduces policies to minimize the redundant work and waiting time among the workers at synchronization points. Graph-based approaches were first introduced to the concept discovery domain to handle the so called local plateau problem. Graph-based approaches have recently gained more popularity in concept discovery system as they provide convenient environment to represent relational data and are able to overcome certain shortcomings of ILP-based concept discovery systems. Graph-based approaches can be classified as structure-based approaches and path-finding approaches. The first class of approaches need to employ expensive algorithms such as graph isomorphism to find frequently appearing substructures. The methods that fall into the second class need to employ sophisticated indexing mechanisms to find out the frequently appearing paths that connect some nodes in interest. In this work, we also propose a hybrid method for graph-based concept discovery which does not require costly substructure matching algorithms and path indexing mechanism. The proposed method builds the graph in such a way that similar facts are grouped together and paths that eventually turn to be concept descriptors are build while the graph is constructed.

Since the population growth of Stockholm Region is rapid, leading to larger demand on Public Transport and especially metro, four Municipalities of the Region have agreed on the expansion of the metro network. Blue metro line will be extended to Nacka and Hagsatra in the south and Barkarby in the north of the Swedish capital. The new railway line connections have been already planned, while the operation of the expanded line is analyzed in the current thesis. Taking the expected increase of passenger volumes and the operation of the current Blue line into account and following the safety restrictions, two alternative regular timetables of the expanded Blue line, limited to the morning rush service on a working weekday, have been constructed. The operation at stations of low expected passenger volume on the train is evaluated concerning the satisfaction of the operator. The rst alternative metro operation with trac every 4 minutes during the rush hour is concluded to be less ecient than the second alternative with 5 minutes headway, as 21 % larger amount of rolling stock is needed and more seats are not occupied. Finally, in order to achieve higher operational eciency at the low-demanded stations, a third Blue line operation, that is based on the second alternative and it includes short services, operating on a part of the line and not on the full-length of it, has been proposed. Although the number of trains needed for the morning peak hour operation remains constant between the second and third alternative operations, the proportion of empty seats at the analyzed stations is expected to be lower during the last alternative operation, resulting in a metro line scheduling that satises the operator most.

Master’s thesis handles about measurement on linear motors. Acts about set of two linear machines on one rail. One is motor and second is load. Thesis paies their mathematical description, control and measurement. It’s made measurement of the linear motor load characteristic. Next measurement have to do with losses in the converter. Is chosen measuring instrument t for measurement during working cycle. During working cycle has determine power eciency of entire drive.