Numer czasopisma
Computer Science
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ISSN: 1508-2806
e-ISSN:
Data wydania
2014
Rocznik
Vol. 15
Numer
No. 2
Prawa dostępu
Dostęp: otwarty dostęp
Uwagi:
Prawa: CC BY 4.0 
Uznanie autorstwa 4.0 Międzynarodowe (CC BY 4.0)
Strony
Opis
Rocznik czasopisma (rel.)
Rocznik czasopisma
Computer Science
Vol. 15 (2014)
Artykuły numeru (rel.)
Artykuł
Dostęp ograniczony
Integration of data from heterogeneous sources using ETL technology
(2014) Macura, Marek
Data integration is a crucial issue in the environments of heterogeneous data sources. At present, the afore-mentioned heterogeneity is becoming widespread. Based on various data sources, if we want to gain useful information and knowledge, we must solve data integration problems in order to apply appropriate analytical methods to comprehensive and uniform data. Such activity is known as knowledge discovery from the data process. Therefore, approaches to the data integration problem are very interesting and bring us closer to the “age of information”. This paper presents an architecture which implements knowledge discovery from the data process. The solution combines ETL technology and a wrapper layer known from mediated systems. It also provides semantic integration through connection mechanism between data elements. The solution allows for integration of any data sources and implementation of analytical methods in one environment. The proposed environment is verified by applying it to data sources in the foundry industry.
Artykuł
Dostęp ograniczony
Context aware handover algorithms for mobile positioning systems
(2014) Silvadorai, Thilek; Chen-Wei, Tan; Ramadass, Sureswaran; Anwar, Toni; Khan, Sazid Zaman
This work proposes context aware handover algorithms for mobile positioning systems. The algorithms perform handover among positioning systems based on important contextual factors related to position determination with efficient use of battery. The proposed solution is implemented in the form of an Android application named Locate@nav6. The performance of the proposed solution was tested in selected experimental areas. The handover performance was compared with other existing location applications. The proposed solution performed correct handover among positioning systems in 95 percent of cases studied while two other applications performed correct handover in only 50 percent of cases studied. Battery usage of the proposed solution is less than one third of the battery usage of two other applications. The analysis of the positioning error of the applications demonstrated that, the proposed solution is able to reduce positioning error indirectly by handing over the task of positioning to an appropriate positioning system. This kept the average error of positioning below 42.1 meters for Locate@nav6 while the average error for two other applications namely Google Latitude and Malaysia maps was between 92.7 and 171.13 meters.
Artykuł
Dostęp ograniczony
Experimental verification of Hyper-V performance isolation quality level
(2014) Rzecki, Krzysztof; Niedźwiecki, Michał; Sośnicki, Tomasz; Martyna, Andrzej
The need for cost optimization in a broad sense constitutes the basis of operation of every enterprise. In the case of IT structure (which is present in almost every field of activity these days), one of the most commonly applied technologies leading to good cost-to-profit adjustment is virtualization. This allows the location of several operational systems with IT systems on a single server. In order for such an optimization to be carried out correctly, it has to be strictly controlled by means of allocating access to resources (which is known as performance isolation). Modern virtualizers allow us to set up this allocation in quantitative terms (the number of processors, size of RAM, or disc space). It appears, however, that in qualitative terms (processor time, RAM, or hard disc bandwidth), the actual allocation of resources does not always correspond with this configuration. This paper provides an experimental presentation of the achievable quality level of performance isolation of the Hyper-V virtualizer.
Artykuł
Dostęp ograniczony
Adaptive SOA stack-based business process monitoring platform
(2014) Dadel, Przemysław; Balawajder, Mariusz; Radziszowski, Dominik; Zieliński, Krzysztof
Executable business processes that formally describe company activities are well placed in the SOA environment, as they allow for the declarative organization of high-level system logic. However, to fully benefit from that element of abstraction, appropriate business process monitoring systems are required for both technical and non-technical users. Unfortunately, current solutions remain unsatisfactory. This paper discusses the problem of business process monitoring in the context of the service orientation paradigm, in order to propose an architectural solution and provide implementation of a system for business process monitoring that alleviate the shortcomings of the existing solutions. Various platforms have been investigated to obtain a broader view of the monitoring problem and to gather functional and non-functional requirements. These requirements constitute input for further analysis and system design. The monitoring software is then implemented and evaluated according to the specified criteria. An extensible business process monitoring system was designed and built on top of OSGiMM – a dynamic, event-driven, configurable communications layer that provides real-time monitoring capabilities for various types of resources. The system was tested against the stated functional requirements, and its implementation provides a starting point for further work. It has been concluded that providing a uniform business process monitoring solution that satisfies a wide range of users and business process platform vendors is a difficult endeavor. It is furthermore reasoned that only an extensible, open source monitoring platform based on a scalable communication core has a chance to address all current and future requirements.
Artykuł
Dostęp ograniczony
Visibility determination in beam tracing with application for real-time sound simulation
(2014) Pałka, Szymon; Głut, Barbara; Ziółko, Bartosz
This work presents some aspects of beam-tracing techniques used in sound simulation. The Adaptive Frustum algorithm, which was designed for detecting obstacles using beam subdivision, was reviewed for its efficiency as well as its accuracy. Some possible improvements have been suggested, however, they do not fully solve the problems of using this algorithm in real-time applications. Improved algorithm implementation was tested in five scenes with different characteristics and varying complexity.
Artykuł
Dostęp ograniczony
Foundational Certification of Code Transformations Using Automatic Differentiation
(2014) Tadjouddine, Emmanuel M; Lv, Wenjin
Automatic Differentiation (AD) is concerned with the semantics augmentation of an input program representing a function to form a transformed program that computes the function’s derivatives. To ensure the correctness of the AD transformed code (particularly for safety-critical applications), we aim at certifying the algebraic manipulations at the heart of the AD process. We have considered a WHILE-language, and have shown how such proofs can be constructed by using appropriate relational Hoare logic. In particular, we have shown how such inference rules can be constructed for both the forward- and reverse-mode AD by using an abductive logical reasoning.