112 research outputs found

    Free and open software for applied statistics. A comparison and a case study in biometrics

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    This article is intended to be a position paper on advantages of free and open software for statistics and its applications to biometrics and biostatistics. Especially, the authors focus on the R package viewed as a new and still insufficiently recognized or received by the scientists, researchers, students, etc. Sample statistical computations and tests in biometrics are presented, and the most common functions and procedures are analysed and compared. Although this is a position paper from the point of view of applied computer science, the authors briefly present some original results within applied statistics (in particular: biometrics) and related computational methods using dedicated software

    Salinity-induced changes in plastoquinone pool redox state in halophytic Mesembryanthemum crystallinum L.

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    We have analyzed the effect of salinity on photosystem II (PSII) photochemistry and plastoquinone (PQ) pool in halophytic Mesembryanthemum crystallinum plants. Under prolonged salinity conditions (7 or 10 days of 0.4 M NaCl treatment) we noted an enlarged pool of open PSII reaction centers and increased energy conservation efficiency, as envisaged by parameters of the fast and slow kinetics of chlorophyll a fluorescence. Measurements of oxygen evolution, using 2,6-dichloro-1,4-benzoquinone as an electron acceptor, showed stimulation of the PSII activity due to salinity. In salt-acclimated plants (10 days of NaCl treatment), the improved PSII performance was associated with an increase in the size of the photochemically active PQ pool and the extent of its reduction. This was accompanied by a rise in the NADP+NADP^{+}/NADPH ratio. The presented data suggest that a redistribution of PQ molecules between photochemically active and non-active fractions and a change of the redox state of the photochemically active PQ pool indicate and regulate the acclimation of the photosynthetic apparatus to salinity

    An Integrated Software Framework for Localization in Wireless Sensor Network

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    Devices that form a wireless sensor network (WSN) system are usually remotely deployed in large numbers in a sensing field. WSNs have enabled numerous applications, in which location awareness is usually required. Therefore, numerous localization systems are provided to assign geographic coordinates to each node in a network. In this paper, we describe and evaluate an integrated software framework WSNLS (Wireless Sensor Network Localization System) that provides tools for network nodes localization and the environment for tuning and testing various localization schemes. Simulation experiments can be performed on parallel and multi-core computers or computer clusters. The main component of the WSNLS framework is the library of solvers for calculating the geographic coordinates of nodes in a network. Our original solution implemented in WSNLS is the localization system that combines simple geometry of triangles and stochastic optimization to determine the position of nodes with unknown location in the sensing field. We describe and discuss the performance of our system due to the accuracy of location estimation and computation time. Numerical results presented in the paper confirm that our hybrid scheme gives accurate location estimates of network nodes in sensible computing time, and the WSNLS framework can be successfully used for efficient tuning and verification of different localization techniques

    Enhanced chloroplastic generation of H_{2}O_{2} in stress-resistant Thellungiella salsuginea in comparison to Arabidopsis thaliana

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    In order to find some basis of salinity resistance in the chloroplastic metabolism, a halophytic Thellungiella salsuginea was compared with glycophytic Arabidopsis thaliana. In control T.s. plants the increased ratios of chlorophyll a/b and of fluorescence emission at 77 K (F_{730}/F_{685}) were documented, in comparison to A.t.. This was accompanied by a higher YII and lower NPQ (non-photochemical quenching) values, and by a more active PSI (photosystem I). Another prominent feature of the photosynthetic electron transport (PET) in T.s. was the intensive production of H_2O_2 from PQ (plastoquinone) pool. Salinity treatment (0.15 and 0.30 M NaCl for A.t. and T.s., respectively) led to a decrease in ratios of chl a/b and F_{730}/F_{685}. In A.t., a salinity-driven enhancement of YII and NPQ was found, in association with the stimulation of H_2O_2 production from PQ pool. In contrast, in salinity-treated T.s., these variables were similar as in controls. The intensive H_2O_2 generation was accompanied by a high activity of PTOX (plastid terminal oxidase), whilst inhibition of this enzyme led to an increased H_2O_2 formation. It is hypothesized, that the intensive H_2O_2 generation from PQ pool might be an important element of stress preparedness in Thellungiella plants. In control T.s. plants, a higher activation state of carboxylase ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco, EC 4.1.1.39) was also documented in concert with the attachment of Rubisco activase (RCA) to the thylakoid membranes. It is supposed, that a closer contact of RCA with PSI in T.s. enables a more efficient Rubisco activation than in A.t

    Bibliografia prac Profesor Hanny Tadeusiewicz

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    Ludzie i książki: studia i szkice bibliologiczno-bibliograficzne: księga pamiątkowa dedykowana Profesor Hannie Tadeusiewicz; rozdziałBibliografia obejmuje dorobek piśmienniczy i dydaktyczny Profesor Hanny Tadeusiewicz z lat 1966-2009 w układzie chronologicznym. Część pierwsza rejestruje publikacje ogłoszone w latach 1966-2009. O zaszeregowaniu publikacji do dane - go roku decydowała data wydania – nie druku. W ramach każdego roku zastoso - wano następujący układ opisów bibliograficznych: publikacje w kolejności alfa - betycznej tytułów, głosy w dyskusji, rozmowy i recenzje oraz prace redagowane. W bibliografii wykorzystano informacje bazy danych Biblioteki Narodowej oraz materiały uzyskane bezpośrednio od Pani Profesor. Przy sporządzaniu spisu ko - rzystano także z roczników Bibliografii Bibliografii i Nauki o Książce . Część opisów bibliograficznych sporządzona została z autopsji. Część druga to bibliografia prac doktorskich i magisterskich przygotowanych pod kierunkiem Profesor Hanny Tadeusiewicz W opisach bibliograficznych, zgodnych z obowiązującymi normami, pominięte zostało tylko nazwisko profesor Hanny Tadeusiewicz jako autorki piśmiennictwa objętego spisem (pozostawiono je natomiast w przypadku prac redagowanych) czy promotora prac magisterskich i doktorskich

    Comparative Study of Supervised Learning Methods for Malware Analysis, Journal of Telecommunications and Information Technology, 2014, nr 4

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    Malware is a software designed to disrupt or even damage computer system or do other unwanted actions. Nowadays, malware is a common threat of the World Wide Web. Anti-malware protection and intrusion detection can be significantly supported by a comprehensive and extensive analysis of data on the Web. The aim of such analysis is a classification of the collected data into two sets, i.e., normal and malicious data. In this paper the authors investigate the use of three supervised learning methods for data mining to support the malware detection. The results of applications of Support Vector Machine, Naive Bayes and k-Nearest Neighbors techniques to classification of the data taken from devices located in many units, organizations and monitoring systems serviced by CERT Poland are described. The performance of all methods is compared and discussed. The results of performed experiments show that the supervised learning algorithms method can be successfully used to computer data analysis, and can support computer emergency response teams in threats detection

    Heavy Gas Cloud Boundary Estimation and Tracking using Mobile Sensors, Journal of Telecommunications and Information Technology, 2016, nr 3

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    This paper addresses issues concerned with design and managing of monitoring systems comprised of mobile wireless sensing devices (MANETs). The authors focus on self-organizing, cooperative and coherent networks that maintain a continuous communication with a central operator and adopt to changes in an unknown environment to achieve a given goal. The attention is focused on the development of MANET for heavy gas clouds detection and its boundary estimating and tracking. Two strategies for constructing the MANET are described, in which sensors explore the region of interest to detect the gas cloud, create temporary network topology and finally, cover the cloud boundary, and track the moving cloud. The utility and efficiency of the proposed strategies has been justified through simulation experiments

    Multiobjective Approachto Localization in Wireless Sensor Networks, Journal of Telecommunications and Information Technology, 2009, nr 3

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    Wireless sensor network localization is a complex problem that can be solved using different types of methods and algorithms. Nowadays, it is a popular research topic. What becomes obvious is that there are several criteria which are essential when we consider wireless sensor networks. Our objective is to determine accurate estimates of nodes location under the constraints for hardware cost, energy consumption and computation capabilities. In this paper the application of stochastic optimization for performing localization of nodes is discussed. We describe two phase scheme that uses a combination of the trilateration method, along with the simulated annealing optimization algorithm. We investigate two variants of our technique, i.e., centralized and distributed. The attention is paid to the convergence of our algorithm for different network topologies and trade-off between its efficiency and localization accuracy

    ASimJava: a Java-based library for distributed simulation, Journal of Telecommunications and Information Technology, 2004, nr 3

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    The paper describes the design, performance and applications of ASimJava, a Java-based library for distributed simulation of large networks. The important issues associated with the implementation of parallel and distributed simulation are discussed. The focus is on the effectiveness of different synchronization protocols implemented in ASimJava. The practical example - computer network simulation - is provided to illustrate the operation of the presented software tool

    A Software Platform for Global Optimization, Journal of Telecommunications and Information Technology, 2010, nr 3

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    This paper addresses issues associated with the global optimization algorithms, which are methods to find optimal solutions for given problems. It focuses on an integrated software environment – global optimization object-oriented library (GOOL), which provides the graphical user interface together with the library of solvers for convex and nonconvex, unconstrained and constrained problems. We describe the design, performance and possible applications of the GOOL system. The practical example – price management problem – is provided to illustrate the effectiveness and range of applications of our software tool
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