174 research outputs found

    6 Access Methods and Query Processing Techniques

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    The performance of a database management system (DBMS) is fundamentally dependent on the access methods and query processing techniques available to the system. Traditionally, relational DBMSs have relied on well-known access methods, such as the ubiquitous B +-tree, hashing with chaining, and, in som

    The 'incidentaloma' of the pituitary gland. Is neurosurgery required?

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    We describe a series of 18 patients with an intrasellar mass incidentally discovered by computed tomography or magnetic resonance imaging. The average size of the mass was 13 mm, with a range from 5 to 25 mm. Initial ophthalmologic examination revealed bitemporal hemianopia in 2 patients. Results of routine endocrine testing showed partial hypopituitarism in 5 patients and growth hormone hypersecretion without signs and symptoms of acromegaly in 1 patient. Four patients underwent neurosurgery. Histologically, one chondroid chordoma and three pituitary adenomas were found. In the remaining 14 patients treated conservatively, repeated computed tomography and magnetic resonance imaging revealed no significant change in tumor size at the time of follow-up (median, 22 months). Our results suggest that the "incidentaloma" of the pituitary gland is a benign condition that does not necessarily require neurosurgical intervention

    Querying now-relative data

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    Challenging Issues of Spatio-Temporal Data Mining

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    The spatio-temporal database (STDB) has received considerable attention during the past few years, due to the emergence of numerous applications (e.g., flight control systems, weather forecast, mobile computing, etc.) that demand efficient management of moving objects. These applications record objects' geographical locations (sometimes also shapes) at various timestamps and support queries that explore their historical and future (predictive) behaviors. The STDB significantly extends the traditional spatial database, which deals with only stationary data and hence is inapplicable to moving objects, whose dynamic behavior requires re-investigation of numerous topics including data modeling, indexes, and the related query algorithms. In many application areas, huge amounts of data are generated, explicitly or implicitly containing spatial or spatiotemporal information. However, the ability to analyze these data remains inadequate, and the need for adapted data mining tools becomes a major challenge. In this paper, we have presented the challenging issues of spatio-temporal data mining. Keywords: database, data mining, spatial, temporal, spatio-tempora

    Benchmarking bitemporal database systems: ready for the future or stuck in the past?

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    Abstract. Introduction: Many strategic investments are often justified with the argument that they will create synergy. For holding mining establishment the goal was more on how to increase business capacity and funding, management of natural resources of mineral and coal, increase value added through downstream and increase local content, as well as cost efficiency through synergy. This paper aims to find the value of synergy in Inalum, PTBA, ANTM and TINS before establishment holding company of mining and the sensitivity the value to different assumptions and how to improve value of synergy in creating a holding company of mining. The major aims of mining holding company to create value and synergy in mining State-Owned Enterprises, with the expectation, it will increase revenue contribution to the country. These goals could be analyzed and measured by understanding of synergy based on two sources of synergies: operating synergy and financial synergy. This paper will assess operating synergy. Methods: In this valuation, Discounted Cash Flow (DCF) Framework will be used to recognize the potential source of synergy from operation. Results: This study found that gain from operation synergy of increasing growth and cost reduction will maximize the business value amounted USD 3,659,295.63, compared to gain from cost reduction USD -14,181,427.91  and gain from increasing growth USD 644,448.44. Conclusion: Given the results from study, it is important to derive the right strategy from investment decision to reflect the optimal source of synergy in order to maximize the business value in Inalum. Keywords:  DCF, investing decision, maximize business value, value of synerg

    A concept/use of temporal Search Engine

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    Modeling temporal dimensions of semistructured data

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    In this paper we propose an approach to manage in a correct way valid time semantics for semistructured temporal clinical information. In particular, we use a graph-based data model to represent radiological clinical data, focusing on the patient model of the well known DICOM standard, and define the set of (graphical) constraints needed to guarantee that the history of the given application domain is consistent

    Bitemporal Sliding Windows

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    The bitemporal data model associates two time intervals with each record - system time and application time - denoting the validity of the record from the perspective of the database and of the real world, respectively. One issue that has not yet been addressed is how to efficiently answer sliding window queries in this model. In this work, we propose and experimentally evaluate a main-memory index called BiSW that supports sliding windows on system time, application time, and both time attributes simultaneously. Our experimental results show that BiSW outperforms existing approaches in terms of space footprint, maintenance overhead and query performance
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