Iraqi Journal for Computers and Informatics

Association rules discovery has emerged as a very important problem in knowledge discovery in database and data mining. A number of algorithms is presented to mine association rules. There are many factors that affect the efficiency of rules mining algorithms, such as largeness, denances, and sparseness of databases used to be mined, in addition to number of items, number and average sizes of transactions, number and average sizes of frequent itemscts, and number and average sizes of potentially maximal itemsets. It is impossible to change present realworld catabase's characteristics to fairly test and determine the best and wurst cases of rule-mining algorithms. to be efficiently used for present and future databases. So the researchers attend to construct artificial database to qualitative and quantitative presence of the above mentioned factors to test the efficiency of rule mining algorithms and programs. The construction of such databases CATmes very large amount of the and efforts. This resent presents a software system, generator, to construct artificial databases.

Audio hiding is method for embedding information into an audio signal. It seeks to do so in a robust Fashion, while not perceivably degrading the host signal (coves audio). Hiding data in audio signals presents & varicty of challenges: due in part to the wider dynamic and differential range of the Human Auditory System (HAS) as compared to other senses. Transform are usually used for robust audio hiding (audio watcrmarking). But, the audio hiding process is affected by the type of transform used. Therefore, this paper presents an evaluation of wavelet transform hiding in comprison with sclccted types of transforms (Walsh transform and cosine transform) hiding. In order to generate the audio stegecover, the research concludce (Wavelet, Walsh, or Cosine) transform of the audio cover, replacing some transformed cover cocfficients with secret audio message coefficients, and inverse (Wavelet, Walsit, or Carsine Irannom for audio cover with replaced coefficients. While, the extracting method concludes (Wavelel, Walsh, or Cosine runsform of the stego ove18 and extracting the secrecy extracted Audio message.

In this paper, a study of the role nf clour information in detecting the edges of an image was conducted Therefore, different colour spaces with components corresponding to the attribute tumance, hue, and saturation le., VHS, and LUVI were implemented.
Two edge delection techniques were applied to each of above colour spaces. These techniques are Sobel operator d Noalincar Laplace operator. A proposed nonlinear Laplace operator was implemented, and in encouraging results indicated its better cticiency than the traditional Tuonlinear Laplace operator. Diffcrcnt approaches were utilized to aclect El threshold value either manually or automatically. The automatic selection depends on the calculation of mean colour gredient magnitude or on the accumulated histogram. A suggestec and implemented mechanism based on using two threshold boundaries to detect edges in colour spaces other than RGB, the results indicated an improvement in the resultant eden image.

There has been a great deal of discussion about null values in relational databases. The relational model was defined in 1969, and Nulls Was died in 1979. Unfortunately, there is not a generally agreeable solution for rull values problem. Null is a special marker which stands for a value undefined or unknown, which means thut ne entry has been made, a missing valuc mark is not a value and not of a date type and cannot be treated as a value by Database Management System (DBMS). As we know, distributed database users are more than a single database and data will be distributed among several data sources or sites, it must be precise data, the replication is allowed there, so complex problems will appear, then there will be need for perfect practical general approaches for treatment of Nulls. A distributed database system is designed, that is "Hotel reservation control system, based on different data sources at four site, each site is represented as a Hotel, for more heterogeneity different application programming languages there are five practical approaches, designed with their rules and algorithms for Null values treatment through the distributed database sites. (1), (2), (3). 14). 15), (9).