Computing and Informatics (E-Journal - Institute of Informatics, SAS, Bratislava)
Not a member yet
1506 research outputs found
Sort by
Integrated System for Hydraulic Simulations
Get PDFThe work described in this paper is aimed at applying and co-operating of modern information technologies and mathematical modeling to make a risk analysis of the water-supply in big cities. It is instrumental in the investigation of the hydraulics of water-supply systems using the simulation model EPANET executed on the underlying high-performance computing infrastructure. The simulation process is integrated with the GIS environment in order to correct input data and visualize the simulation output. Input data for the model can be modified directly within the designed scientific gateway which enables hydraulic domain experts to interact comfortably with the HPC capacity. Furthermore, the system includes some data mining capabilities forming bridges between the hydraulic data storage and available hydrological measurements focused on water consumption modeling and predictions. In simulating the main emphasis is given to optimize the measure of a similarity between the mathematical model and the real system in order to obtain reliable results
Modelling of Hazards Effect on Safety Integrity of Open Transmission Systems
Get PDFThe paper is concerned with safety appraisal of safety-related communication systems (SRComSs) with open transmission system, where except in addition to message transmission integrity also confidentiality is recommended to be provided. The authors focused on safety analysis of safety-related messages transmission secured using cryptographic and safety code mechanisms and on the possibilities of modelling safety-related industrial communication system, where a high safety integrity level SIL3 is required to be guaranteed. The paper features mathematical procedures to calculate the rate of hazardous transmission failure of safety-related messages in the result of electromagnetic interference (EMI) effects in the communication channel and by the presence of random hardware failures of SRComS. The theoretical techniques and safety analyses emerge from risk analysis and are compared with the knowledge gained by the authors during safety verifications of such systems for transportation applications. It is a little explored area, because the standards concerning safety-related control systems (SRCSs) did not support any cryptography-based methods. A quantitative safety integrity analysis of SRComS is based on utilisation of Markov's processes. The proposed Markov's model is applied on an open transmission system built on the IEEE 802.11g standard, which is complemented by cryptographic and safety code. The calculations are performed using Mathematica software tool. The proposed base model is universal and can be modified (simplified) in dependence on the parameters of a specific SRComS
A New Confirmation Framework for Extracting Synonymous Chinese Transliteration Based on Pronunciation Model
Get PDFThere is no transliteration standard across all Chinese language regions, including China, Hong Kong, and Taiwan, and variations in Chinese transliteration have thus arisen in the process of transliterating foreign languages (English, for instance) into the Chinese language. In this paper, we propose an integrated confirmation framework to confirm a pair, that is, a transliteration and another term, whether it is synonymous. This framework includes two major steps. First, we study methods from several pronunciation-based approaches to measure similarity between Chinese characters; these approaches are specified for the comparison of Chinese synonymous transliterations. Second, we construct a new confirmation framework to confirm whether a pair of a Chinese transliteration and another Chinese term is synonymous. The presented framework is applied to extract synonymous transliteration pairs from a real-world Web corpus; this is valuable to build a new database of synonymous transliterations or support search engines so that they can return much more complete documents as Web search results to increase the usages in practice. Experiments show that our integrated confirmation framework is effective and robust in confirming and extracting pairs of Chinese transliteration following the collection of synonymous transliterations from the Web corpus
Generalized Multisets: From ZF to FSM
Get PDFWe study generalized multisets (multisets that allow possible negative multiplicities) both in the Zermelo-Fraenkel framework and in the finitely supported mathematics. We extend the notion of generalized multiset over a finite alphabet, and we replace it by the notion of algebraically finitely supported generalized multiset over a possibly infinite alphabet. We analyze the correspondence between some properties of generalized multisets obtained in finitely supported mathematics where only finitely supported objects are allowed, and those obtained in the classical Zermelo-Fraenkel framework
Introducing Versioning-Based Software Online Upgrade Framework over a Peer-to-Peer Network
Get PDFSpeed and trend in the software evolution demand the more flexible and available software. For the large-scale software, the availability and automation of current software online upgrade approach is not ideal, which brings the managers much work to maintain all the versions of software. In this paper, we introduce the versioning-based software online upgrade framework (VSOUF) over BitTorrent-like Peer-to-Peer (P2P) Network. The distributed hash table (DHT) layer and version control (VC) layer is the core of this framework. Software clients can carry out initializing and upgrading by the atomic operations of a version control. Borrowing from P2P, we weave the distributed hash table (DHT) algorithm to speed up the download rate of a version control so that this framework will not crash under the failure of a single node. Finally, experiments have showed the high performance and availability of the proposed framework
Effective Scheduling of Grid Resources Using Failure Prediction
Get PDFIn large-scale grid environments, accurate failure prediction is critical to achieve effective resource allocation while assuring specified QoS levels, such as reliability. Traditional methods, such as statistical estimation techniques, can be considered to predict the reliability of resources. However, naive statistical methods often ignore critical characteristic behavior of the resources. In particular, periodic behaviors of grid resources are not captured well by statistical methods. In this paper, we present an alternative mechanism for failure prediction. In our approach, the periodic pattern of resource failures are determined and actively exploited for resource allocation with better QoS guarantees. The proposed scheme is evaluated under a realistic simulation environment of computational grids. The availability of computing resources are simulated according to real trace that was collected from our large-scale monitoring experiment on campus computers. Our evaluation results show that the proposed approach enables significantly higher resource scheduling effectiveness under a variety of workloads compared to baseline approaches
Assessing Cognitive Complexity in Java-Based Object-Oriented Systems: Metrics and Tool Support
Get PDFSoftware cognitive complexity refers to how demanding the mental process of performing tasks such as coding, testing, debugging, or modifying source code is. Achieving low levels of cognitive complexity is crucial for ensuring high levels of software maintainability, which is one of the most rewardful software quality attributes. Therefore, in order to control and ensure software maintainability, it is first necessary to accurately quantify software cognitive complexity. In this line, this paper presents a software metric to assess cognitive complexity in Object-Oriented (OO) systems, and particularly those developed in the Java language, which is very popular among OO programming languages. The proposed metric is based on a characterization of basic control structures present in Java systems. Several algorithms to compute the metric and their materialization in the Eclipse IDE are also introduced. Finally, a theoretical validation of the metric against a framework specially designed to validate software complexity metrics is presented, and the applicability of the tool is shown by illustrating the metric in the context of ten real world Java projects and relevant metrics from the well-known Chidamber-Kemerer metric suite
Thai Multi-Document Summarization: Unit Segmentation, Unit-Graph Formulation, and Unit Selection
Get PDFThere have been several challenges in summarization of Thai multiple documents since Thai language itself lacks of explicit word/phrase/sentence boundaries. This paper gives definition of Thai Elementary Discourse Unit (TEDU) and then presents our three-stage summarization process. Towards implementation of this process, we propose unit segmentation using TEDUs and their derivatives, unit-graph formation using iterative unit weighting and cosine similarity, and unit selection using highest-weight priority, redundancy removal, and post-selection weight recalculation. To examine performance of the proposed methods, a number of experiments are conducted using fifty sets of Thai news articles with their manually constructed reference summary. By three common evaluation measures of ROUGE-1, ROUGE-2, and ROUGE-SU4, the results evidence that (1) our TEDU-based summarization outperforms paragraph-based summarization, (2) our iterative weighting is superior to traditional TF-IDF, (3) the highest-weight priority without centroid preference and unit redundancy consideration helps improving summary quality, and (4) post-selection weight recalculation tends to raise summarization performance under some certain circumstances
Energy Efficient XPath Query Processing on Wireless XML Streaming Data
Get PDFAn energy efficient way of disseminating XML data to several mobile clients is broadcast. Information such as alert on emergencies, election results and sporting event results can be of interest to large number of mobile clients. Since eXtensible Markup Language (XML) is widely used for information exchange, wireless information services require an energy efficient XML data dissemination. XML Path (XPath) represents selective data required by mobile clients. XPath query processing involves two performance metrics, namely tune-in time and access time. In this paper, we propose a novel structure for streaming XML data called Path Stream Group Level (PSGL) node by exploiting the tree structure of XML document. It possesses various small indices such as level, child, sibling, attribute, text for selective download of XML data by mobile clients. It organizes data based on the level of XML document tree and groups XML elements with same XML path prefix to conserve battery power at mobile clients. Experimental results show that proposed method has reduced tune-in time when compared with existing approaches. Hence PSGL approach enhances performance with energy conservation for processing various types of XPath queries
Implementing the Factory Pattern with the Help of Reflection
Get PDFReflection, reflection-based programming and metaprogramming are valuable tools for many programming tasks, like the implementation of persistence and serialization-like operations, object-relational mapping, remote method invocation, automatic generation of user-interfaces, etc., and also for the implementation of several design patterns. C++ as one of the most prevalent programming languages still lacks support for standardised, compiler-assisted reflection. In this paper we introduce in short the Mirror reflection library which is a part of an ongoing effort to add reflection to C++ and we will show how reflection can be used to greatly simplify the implementation of object factories - classes constructing instances of other classes from various external data representations