With the growth of computer networks and the advancement of hardware technologies, unprecedented access to data volumes become accessible in a distributed fashion forming heterogeneous data sources. Understanding and combining these data into data warehouses, or merging remote public data into existing databases can significantly enrich the information provided by these data. This problem is called data integration: combining data residing at different sources, and providing the user with a unified view of these data. There are two issues with making use of remote data sources: (1) discovery of relevant data sources, and (2) performing the proper joins between the local data source and the relevant remote databases. Both can be solved if one can effectively identify semantically-related attributes between the local data sources and the available remote data sources. However, performing these tasks manually is time-consuming because of the large data sizes and the unavailability of schema documentation; therefore, an automated tool would be definitely more suitable. Automatically detecting similar entities based on the content is challenging due to three factors. First, because the amount of records is voluminous, it is difficult to perceive or discover information structures or relationships. Second, the schemas of the databases are unfamiliar; therefore, detecting relevant data is difficult. Third, the database entity types are heterogeneous and there is no existing solution for extracting a richer classification result from the processing of two different data types, or at least from textual and numerical data. We propose to utilize self-organizing maps (SOM) to aid the visual exploration of the large data volumes. The unsupervised classification property of SOM facilitates the integration of completely unfamiliar relational database tables and attributes based on the contents. In order to accommodate heterogeneous data types found in relational databases, we extended the term frequency – inverse document frequency (TF-IDF) measure to handle numerical and textual attribute types by unified vectorization processing. The resulting map allows the user to browse the heterogeneously typed database attributes and discover clusters of documents (attributes) having similar content. iii The discovered clusters can significantly aid in manual or automated constructions of data integrity constraints in data cleaning or schema mappings for data integration.

This work analyzes the effects that different information structures on the demand side of the market have on consumption decisions and the way prices are determined. We develop three theoretical models to address this issue in a systematic way. First, we focus our attention on the consumers' awareness, or lack thereof, of substitute products in the market and the strategic interaction between firms competing in prices and costly advertising in such an environment. We find that prior information held by consumers can drastically change the advertising equilibrium predictions. In particular, we provide sufficient conditions for the existence of three types of equilibria, in addition to one previously found in the literature, and provide a necessary condition for a fourth type of equilibrium. Additionally, we show that the effect of the resulting advertising strategies on the expected transaction price is qualitatively significant, although ambiguous when compared to the case of a newly formed market. We can establish, however, that the transaction price is increasing in the size of the smaller firm's captive market. In the second chapter, we study the optimal timing to buy a durable good with an embedded option to resell it at some point in the future, as well as its reservation price, where the agent faces Knightian uncertainty about the process generating the market prices. The problem is modeled as a stopping problem with multiple priors in continuous time with infinite horizon. We find that the direction of the change in the buyer's reservation price depends on the particular parametrization of the model. Furthermore, the change in the buying threshold due to an increase in ambiguity is greater as the fraction of the market at which the agent can resell the good decreases, and the value of the embedded option is decreasing in the perceived level of ambiguity. Finally, we introduce Knightian uncertainty to a model of price search by letting the consumers be ambiguous regarding the industry's cost of production. We characterize the equilibria of this game for high and low levels of the search cost and show that firms extract abnormal profits for low realizations of the marginal cost. Furthermore, we show that, as the search cost goes to zero, the equilibrium of the game under the low cost regime does not converge to the Bertrand marginal-cost pricing. Instead firms follow a mixed-strategy that includes all prices between the high and low production costs. / text

Tyrimo „Lietuvos ir Latvijos profesinio orientavimo sistemos 1990 – 2012“ tikslas yra atlikti Lietuvos ir Latvijos profesinio orientavimo sistemų, paslaugų teikėjų (institucijų, kurios yra atsakingos už profesinio orientavimo paslaugų teikimą, kokybę, plėtotę) lyginamąją analizę. Tyrimo ataskaitą sudaro 4 skyriai. Pirmame skyriuje analizuojama ir lyginama abiejų šalių profesinio orientavimo sistemų raida nuo 1990 m. iki 2012 m. Antrame skyriuje analizuojamos ir lyginamos profesinio informavimo struktūros t.y., už profesinį orientavimą atsakingos institucijos. Trečiame skyriuje analizuojamos ir lyginamos Lietuvos ir Latvijos profesinio informavimo internetinės duomenų bazės. Ketvirtame skyriuje lyginami Lietuvos ir Latvijos profesinį orientavimą reglamentuojantys teisiniai dokumentai.Tyrimas grindžiamas prielaida, kad Lietuvos ir Latvijos profesinio orientavimo sistemos plėtojamos skirtingai, nepaisant to, kad yra kaimyninės šalys ir jas sieja istoriniai bei politiniai įvykiai. Atlikus tyrimą nustatyta, kad Lietuvos ir Latvijos profesinio orientavimo sistemos yra plėtojamos skirtingai, nes: priimami skirtingo pobūdžio įstatymai, orientuojamasi į skirtingas profesinio orientavimo sistemos dalis ir t.t. Nors rasta ir labai daug panašumų: Europos Sąjungos fondų vykdyti tokie pat arba panašūs projektai, sutampa, kai kurių už profesinį orientavimą atsakingų institucijų veiklą ir t.t. Tačiau negalima patvirtinti, kad Lietuvos profesinio orientavimo sistema yra labiau išvystyta negu... [toliau žr. visą tekstą] / The aim of the research “Lithuanian and Latvian Systems of Professional Orientation in 1990-2012” is to perform a comparative analysis between the Lithuanian and Latvian vocational guidance systems and the service providers (institutions, responsible for vocational guidance service providing, their quality and development). The research report consists of 4 chapters. In the first one, there are analysed and compared the development of vocational guidance systems from 1900 till 2012 in both countries. In the second chapter, there are analysed and compared professional information structures, i. e. institutions, responsible for vocational guidance. In the third chapter, there are analysed and compared internet data bases of the Lithuanian and Latvian professional information. In the last chapter of the report, the legal documents regulating the Lithuanian and Latvian vocational guidance are compared. The research is grounded on the assumption that despite the Lithuanian and Latvian common historical and political events, the vocational guidance systems are developed differently in both countries. The research showed that the Lithuanian and Latvian vocational guidance systems are developed differently, because: the legislation is drafted of different character, it is oriented to different vocational guidance systems parts, etc. Even though there were certain similarities found: same projects, developed by the European Union funds, activity of some institutions, responsible for... [to full text]

<p>Systems engineering (SE) is an increasingly relevant domain in an increasingly interconnected world, but the demand for SE education is impeded by the challenges of effectively teaching interdisciplinary material that emphasizes the development of a mentality over specific skills. A modularized, asynchronous, distributed course configuration may provide an advantageous alternative to more traditional hybrid course designs. Online courses have been a topic in the educational field since the establishment of the internet. However, the widespread disruptions to higher education due to the COVID-19 pandemic highlighted the demand for and difficulty of developing deliberate and robust learning environments designs that consider a variety of traditional and non-traditional students. This thesis presents a case design of a learning environment for an interdisciplinary-focused, introductory graduate-level systems course that has previously been designed for, and taught in, a hybrid environment. The case design will emphasize the information architecture (IA) and user experience (UX) prototype design of the learning environment as informed by user-centric principles, cognitive theories and analyses, the IA literature, and existing course content. This focus on learner knowledge development (“beyond-the-screen”) factors rather than the direct user interface (“at-the-screen”) provides design recommendations and insights that are robust to changing user interface trends and preferences. A distribution of learners with varying backgrounds, learning needs, and goals associated with the material will be identified. These individual differences can dramatically impact the effectiveness of potential interventions, particularly when different types of learners have directly conflicting needs. Thus, the online learning environment will utilize adaptable interfaces to move away from a “one-size-fits-all” design approach. Content modularization and non-sequential, tag-based navigation were utilized to address the challenges of teaching highly interdisciplinary material. This thesis emphasizes a learning environment design that aims to teach highly interdisciplinary systems subject matter to a variety of learners with a variety of characteristics in an asynchronous, online format while making use of existing course material. </p>