KeyFinder: An Efficient Minimal Keys Finding Algorithm For Relational Databases

In relational databases, it is essential to know all minimal keys since the concept of database normaliza-tion is based on keys and functional dependencies of a relation schema. Existing algorithms for determining keysor computing the closure of arbitrary sets of attributes are generally time-consuming. In this paper we present anefficient algorithm, called KeyFinder, for solving the key-finding problem. We also propose a more direct methodfor computing the closure of a set of attributes. KeyFinder is based on a powerful proof procedure for findingkeys called tableaux. Experimental results show that KeyFinder outperforms its predecessors in terms of searchspace and execution time.

A Method for Normalization of Relation Schema Based on Data to Abide by the Third Normal Form

Data bases play an important role in applied Mathematics. Normalization for relational databases is very important to avoid anomalies of relations which may not be in normalized forms of the third normal forms. But, normalization may be a difficult task, since the designers of the databases may not fully understand the domain of each attribute that are contained in the relation schema or they may not have full understanding about the concept of normalization. In this paper an efficient method that checks the possibility of the need of further normalization using stored data in relations is presented based on possible functional dependencies between attributes in the relations. By checking possible functional dependencies, the database designers can determine the need of further normalization, and may improve the structure of the relation schemas. Experiments were performed for an example of relational database that can be found in the organization of tutorial of MySQL which is a representational database management system, and the experiments showed good results.

DISCOURSE OF GOVERNOR ELECTION IN LOCAL MEDIA

The study discussed the construction of the reality of governor election in local media or a study of political communication on the 2018 South Sulawesi governor candidates in Harian Fajar and Celebes TV. The objectives of the study were to analyze the news text of the 2018 South Sulawesi governor candidates in Harian Fajar and Celebes TV, as well as the discourse practices of the Harian Fajar and Celebes TV in constructing the reality of the South Sulawesi governor election in 2018. The results revealed that Harian Fajar news text and Celebes TV broadcast program tended to construct the populist issues regarding political realities ahead of the 2018 South Sulawesi governor election. The prominence of elite forces, political parties and dominant groups as well as marginalization of the governor election contestant positions were constructed in the news text with an emphasis on discourse elements; semantic, stylistic, relation schema and identity of political actors. The construction of news texts on the reality of the 2018 South Sulawesi governor election provided an impression that local media entities were characterized as followers of particular parties, yet their partiality towards the interests of the dominant group was faintly and dramatically occured by controlling the text interdiscursively. The practice of discourse in the editorial room indicated that the central role of the editor was not only limited to the agent of defining reality, but also as a political player in the contestation of the 2018 South Sulawesi governor election discourse. The editor possessed power over the text that was able to create political issues in the news as well as having the power to determine the direction of the discourse constructed.

Effects of Cooling Rate on Morphology, Microhardness and Volume Fraction of Mg-Zn-Y Quasicrystals

Mg72.5Zn26Y1.5 (at.%) quasicrystal alloys were investigated under different solidification conditions. The cooling curves were gathered by the multi-channel temperature acquiring system and the corresponding microstructures were analyzed. The morphology, microhardness and volume fraction of quasicrystals were detailedly studied. The effects of cooling rate on the above three aspects were also studied and the relation schema among them were exhibited. The results show that the quasicrystal size tend to smaller, its microhardness and volume fraction gradually increased, and the quasicrystal morphology changed from bulk polygon to petal-like and finally changed to plat X-shape with the elevated cooling rate from 2.3K/s to 181.2K/s. However, the quasicrystal nucleation will be restrained and amorphous matter will be created if the cooling rate exceed the critical point which make against the formation of quasicrystals with high performance.