206 research outputs found

    Three Denerations of DBMS

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    This paper describes the evolution of data base technology from early computing to the sophisticated systems of today. It presents an overview of the most popular data base management systems architectures such as hierarchical, network, relational and object-oriented. The last section of this paper presents a view of the factors that will influence the future of data base technology

    Content-based image retrieval and its benefits for the stock photography market

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    The development of powerful low-cost desktop computer systems has changed the pre-press business where tight deadlines must be met per sistently. An increasing number of newspapers and magazines are acquiring, handling, and storing images digitally while the use of hardcopies and slides decreases. Today\u27s computers and high capacity storage-media enable stock pho tography agencies to build digital image databases, giving users fast access to large numbers of images. However, the transition from analog to digital image archives imposes new problems: with thousands of images at hand, the search for a particular image may turn into the search for the needle in a haystack. The first image Database Management Systems (DBMSs) were extended text DBMSs, which stored the image data along with a set of manually entered descriptive keywords. The major problem with this approach is that there is no generally agreed-upon language to describe images. Even sophis ticated DBMSs are unable to detect synonyms; hence, an image described with certain properties such as curvy may not be found if a user enters wavy as a search criterion. Furthermore, some image properties are hard to describe with keywords. A search is likely to fail if properties were not described at the database population stage when images are added to the database. Finally, assigning a sufficient set of keywords to every image adds a tremendous amount of labor to the population stage. Research at many scientific institutions and companies is geared towards overcoming the shortcomings of image DBMSs with keyword-based search engines. Pattern recognition which allows for comparing images based on their visual content is being introduced to image DBMSs, improving the accuracy of search engines. Sketches, sample images, and other means of describing the visual content of images may be used as search criteria in addition to keywords. This thesis project summarizes the basics of pattern recognition and its applications in image database management for contentbased image retrieval. The purpose of this thesis project is to determine the impact of contentbased image retrieval on the stock photography market in the near future. In order to obtain the necessary information, two different questionnaires were sent out to a number of selected stock photography agencies, newspapers, and magazines. The evaluation of the replies was conducted for the three groups separately. The replies from stock photography agencies showed a high interest in digital image archives. They also showed concerns about increased overhead with digital archives. The estimated amount of work required for categoriz ing images and assigning keywords ranged from fifty to ninety percent as compared to ten to fifty percent for scanning. All survey participants agreed that pattern recognition can improve the accuracy of keyword-based search engines. However, they all denied that this approach would reduce the need for assigning keywords. Different needs could be determined for newspaper and magazines. Newspapers rely heavily on keywords since images are often chosen based upon the circumstances under which they were taken while their visual con tent may be secondary. Therefore, newspapers\u27 profits from content-based image retrieval are minute. For magazines, the visual content of images seemed to have a higher priority and the appreciation for corresponding search capabilities was accordingly higher. To summarize, users of digital image archives can profit from contentbased image retrieval if the visual content is an important issue. For image providers, there are a number of reasons that delay the transition to contentbased image retrieval. Currently, there is only one shrink-wrapped commer cial product available that meets the needs of stock photography agencies. This product requires additional work for fully exhausting its capabilities. Finally, many companies have already built their image database and the transition to another system is time-consuming, expensive, and risky

    Assessment of classical database models for representing solids

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    Solid modeling is being explored as a method of representing three dimensional parts for mechanical design and manufacturing. This work analyzes the data storage requirements of the Boundary Representation and Constructive Solid Geometry methods of representing solid models. The ability of the database models (Hierarchical, Network, and Relational) to support solid modeling needs is evaluated. The goal is to determine the database model(s) best suited to store and manage the graphical data for solid model representat ions . Background information about mechanical engineering, graphics, and database models is presented. Entity-Relationship diagrams are used to define data requ irements

    The impact of triggers on forensic acquisition and analysis of databases

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    An aspect of database forensics that has not received much attention in the academic research community yet is the presence of database triggers. Database triggers and their implementations have not yet been thoroughly analysed to establish what possible impact they could have on digital forensic analysis methods and processes. This paper firstly attempts to establish if triggers could be used as an anti-forensic mechanism in databases to potentially disrupt or even thwart forensic investigations. Secondly, it explores if triggers could be used to manipulate ordinary database actions for nefarious purposes and at the same time implicate innocent parties. The database triggers as defined in the SQL standard were studied together with a number of database trigger implementations. This was done in order to establish what aspects of a trigger might have an impact on digital forensic analysis. It is demonstrated in this paper that certain database forensic acquisition and analysis methods are impacted by the possible presence of non-data triggers. This is specific to databases that provide non-data trigger implementations. Furthermore, it finds that the forensic interpretation and attribution processes should be extended to include the handling and analysis of all database triggers. This is necessary to enable a more accurate attribution of actions in all databases that provide any form of trigger implementations.“The Role of Triggers in Database Forensics”, by Werner Hauger and Martin Olivier which appeared in the Proceedings of Information Security South African (ISSA) 2014, Johannesburg, 13 & 14 August 2014.http://www.saiee.org.za/DirectoryDisplay/DirectoryCMSPages.aspx?name=Publications#id=1588&dirname=ARJ&dirid=337am2016Computer Scienc

    Database development and intranet based image included database management system for ballistic firearm identification system

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    The process of imaging, collecting and searching a cartridge case to identifying its suspected firearm is a time consuming procedure. Within this study, a cartridge case identification database management system in an Intranet environment is designed and implemented, thus enabling firearm examiners from different forensic laboratories to engage firearm identification without the constraints of time and location. Specifically, the study investigates appropriate database management system for image involved and Intranet secured ballistics firearm identification database. The results demonstrated that a computerized firearm identification system could be implemented in Intranet with a secure, scalable, performable Intranet database management system

    A Survey of Traditional and Practical Concurrency Control in Relational Database Management Systems

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    Traditionally, database theory has focused on concepts such as atomicity and serializability, asserting that concurrent transaction management must enable correctness above all else. Textbooks and academic journals detail a vision of unbounded rationality, where reduced throughput because of concurrency protocols is not of tremendous concern. This thesis seeks to survey the traditional basis for concurrency in relational database management systems and contrast that with actual practice. SQL-92, the current standard for concurrency in relational database management systems has defined isolation, or allowable concurrency levels, and these are examined. Some ways in which DB2, a popular database, interprets these levels and finesses extra concurrency through performance enhancement are detailed. SQL-92 standardizes de facto relational database management systems features. Given this and a superabundance of articles in professional journals detailing steps for fine-tuning transaction concurrency, the expansion of performance tuning seems bright, even at the expense of serializabilty. Are the practical changes wrought by non-academic professionals killing traditional database concurrency ideals? Not really. Reasoned changes for performance gains advocate compromise, using complex concurrency controls when necessary for the job at hand and relaxing standards otherwise. The idea of relational database management systems is only twenty years old, and standards are still evolving. Is there still an interplay between tradition and practice? Of course. Current practice uses tradition pragmatically, not idealistically. Academic ideas help drive the systems available for use, and perhaps current practice now will help academic ideas define concurrency control concepts for relational database management systems
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