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Scientific Collaboration, Citation and Topic Analysis of International Conference on Agile Software Development Papers
- Muhammad Ahmad
- Päivi Raulamo-jurvanen
2020
The International Conference on Agile Software Development (XP) was established almost sixteen years ago. Based on data from Scopus database, a total of 789 papers have been published in between years of 2002 and 2018. We employed bibliometrics analysis and topic modeling with R/RStudio to analyze these published papers from various dimensions, including the most active authors, collaboration of authorship, most cited papers, used keywords and trends of probable topics from the titles and abstracts of those papers. The results show that the first five years of XP conference cover nearly 40% of the papers published until now and almost 62% of the XP papers have been cited at least once. Mining of XP conference paper titles and abstracts result in these hot research topics: “Coordination”, “Technical Debt”, “Teamwork”, “Startups” and “Agile Practices”, thus strongly focusing on practical issues and problems faced by the practitioners in the industry. The results highlight the most influential researchers and institutions, and the collaboration between the authors in the conference papers. The approach applied in this study can be extended to other software engineering venues and can be applied to large-scale studies.
Seabed Topography Changes in the Sopot Pier Zone in 2010–2018 Influenced by Tombolo Phenomenon
- Artur Makar
- Cezary Specht
- Mariusz Specht
- Paweł Dąbrowski
- Paweł Burdziakowski
- Oktawia Lewicka
2020 Pełny tekst SENSORS
Bathymetric surveys of the same body of water, performed at regular intervals, apart from updating the geospatial information used to create paper and electronic maps, allow for several additional analyses, including an evaluation of geomorphological changes occurring in the coastal zone. This research is particularly important in places where the shape of the coastal zone has been violently disturbed, including by human activity. Tombolo is such a phenomenon and it dynamically shapes the new hydrological conditions of the coastal zone. Apart from natural factors, it may be caused by the construction of hydrotechnical facilities in the littoral zone. It causes a significant disturbance in the balance of the marine environment, resulting in the bottom accretion and dynamic changes in the coastline. This has been the case since 2010 in Sopot, where the rapidly advancing tombolo is not only changing environmental relations but also threatening the health-spa character of the town by stopping the transport of sand along the coast. This paper analyses changes in seabed shape in the pier area in Sopot between 2010 and 2018. In the analysis, both archival maps and bathymetric surveys over a period of 8 years were used; based on these, numerical bottom models were developed and their geospatial changes were analyzed. The results showed that changes in the seabed in this area are progressing very quickly, despite periodic dredging actions organized by administrative bodies.
Searching for Solvents with an Increased Carbon Dioxide Solubility Using Multivariate Statistics
- Marta Bystrzanowska
- Marek Tobiszewski
- Francisco Pena-Pereira
- Vasil Simeonov
2020 Pełny tekst MOLECULES
Ionic liquids (ILs) are used in various fields of chemistry. One of them is CO2 capture, a process that is quite well described. The solubility of CO2 in ILs can be used as a model to investigate gas absorption processes. The aim is to find the relationships between the solubility of CO2 and other variables—physicochemical properties and parameters related to greenness. In this study, 12 variables are used to describe a dataset consisting of 26 ILs and 16 molecular solvents. We used a cluster analysis, a principal component analysis, and a K-means hierarchical clustering to find the patterns in the dataset and the discriminators between the clusters of compounds. The results showed that ILs and molecular solvents form two well-separated groups, and the variables were well separated into greenness-related and physicochemical properties. Such patterns suggest that the modeling of greenness properties and of the solubility of CO2 on physicochemical properties can be difficult.
Seashore sediment and water chemistry at the Admiralty Bay (King George Island, Maritime Antarctica) – geochemical analysis and correlations between the concentrations of chemical species
- Joanna Potapowicz
- Danuta Szumińska
- Małgorzata Szopińska
- Robert Józef Bialik
- Katarzyna Machowiak
- Stanisław Chmiel
- Żaneta Polkowska
2020 MARINE POLLUTION BULLETIN
This study covers water and sediment chemical characteristics by the western shore of Admiralty Bay (King George Island, Antarctica) in 2016. Chemical processes between sediment and water have been described based on the determination of ions, metals, non-metals, and TOC concentrations. Rock weathering is an important source of Fe, Ni, Co, Al in the seashore area. The PCA shows the impact of acidification in the release metals from sediment. Our results indicate that riverine mineral fluxes need to be accounted for as the volume of melt increases in response to climate change. Based on geoaccumulation indexes (anthropogenic fingerprint), we observed an increased concentration of Pb (Igeo=1.643), in the lake near station facilities and Cd in the area of Ecology Glacier (Igeo>1.389). Taking into account climate change and the intensification of anthropopressure, our study indicates that Antarctica requires a special focus on the seasonal dynamics of mineral content and pollution assessment.
Seasonal contributions of nutrients from small urban and agricultural watersheds in northern Poland
- Karolina Matej-Łukowicz
- Ewa Wojciechowska
- Nicole Nawrot
- Lidia Dzierzbicka-Głowacka
2020 Pełny tekst PeerJ
Diffuse sources of pollution like agricultural or urban runoff are important factors in determining the quality of surface waters, although they are more difficult to monitor thanpointsources.Theobjectiveofourstudywastoverifyassumptionsthattheinflow from agricultural nutrient sources is higher than from urbanized ones. It has been done by comparing the nutrients and organic matter concentrations and loads for three small streams in northern Poland (Pomerania Region). Two streams flowing through agricultural catchments and an urban stream flowing through the city of Gdansk were analysed. Concentrations of nutrients: N-NO− 3 N-NH+ 4 , P-PO3− 4 , total phosphorus, total nitrogen and COD were measured 1–3 times per month in the periodfromJuly2017toDecember2018inagriculturalwatershedsandfromOctober 2016 to March 2018 for an urban stream. Seasonal changes in concentrations were analysed with descriptive statistics tools. Principal Component Analysis (PCA) was used to point out the most significant factors determining variations in nutrients and organic matter concentrations with respect to different seasons. The factors included a number of characteristics regarding the catchment and streams: total catchment area, stream length, watershed form ratio, stream slope, flow rate and land use with respecttopavedareas,agriculturalareasandgreenareas(parks,forests,meadowsand pastures). Although concentrations of nitrogen compounds were higher in streams flowing through agricultural areas, our study showed that total concentrations of phosphoruswerehigherintheurbanstream,especiallyinsummer.Inagriculturalareas thesummerconcentrationsofnutrientswerenothigh,whichwasprobablyduetodense vegetation.ThecorrelationbetweenP-PO3− 4 concentrationandsizeofagriculturalarea in the catchment was observed in winter when no vegetation field cover exists. Our study shows an urgent need to monitor the nutrient loads carried with urban streams especially if discharged into receivers prone to eutrophication.
Secured wired BPL voice transmission system
- Grzegorz Debita
- Przemysław Falkowski-Gilski
- Marcin Habrych
- Bogdan Miedziński
- Jan Wandzio
- Przemysław Jedlikowski
2020 Pełny tekst Scientific Journal of the Military University of Land Forces
Designing a secured voice transmission system is not a trivial task. Wired media, thanks to their reliability and resistance to mechanical damage, seem an ideal solution. The BPL (Broadband over Power Line) cable is resistant to electricity stoppage and partial damage of phase conductors, ensuring continuity of transmission in case of an emergency. It seems an appropriate tool for delivering critical data, mostly clear and understandable voice messages. This paper describes such a system that was designed and evaluated in real-time operating conditions. It involved a two-way transmission of speech samples in American English and Polish. The efficiency of the designed solution was evaluated in the subjective study on a group of 15 people.
Selected adipocytokines in patients with an incidentally discovered pheochromocytoma
- Mariusz Kaszubowski
- Ania Babińska
- P. Kmieć
- Krzysztof Sworczak
2020 Minerva Endocrinologica
BACKGROUND: Adipose tissue secretes many adipokines and cytokines, which may be an additional risk factor of cardiovascular and metabolic diseases in patients with an incidentally discovered pheochromocytoma (PHEO). The aim of the study was to investigate levels of selected adipocytokines in these patients. METHODS: This prospective study included 12 patients with an incidentally discovered PHEO and 18 healthy participants. In all participants plasma/serum concentrations of triglycerides, HDL and LDL cholesterol, insulin, glucose, adipocytokines (adiponectin, leptin, resistin, TNFα, IL6, and MCP1) were determined, hormonal tests were performed in patients. RESULTS: Patients and controls did not differ significantly in terms of age, sex, and body mass index. Among incidentally discovered PHEO patients, adiponectin levels were lower, while TNFα concentrations higher than in controls. Concentrations of adiponectin correlated with 24-hour urinary excretion of normetanephrine in women. Significantly higher TNFα concentrations were found in hypertensive than in normotensive PHEO patients as well as in non-diabetic PHEO patients than controls. Further, resistin concentration was higher in PHEO patients with diabetes than in non-diabetic ones (p<0.001). Incidentally discovered PHEO tumor size correlated with leptin and IL6 levels. Adiponectin levels were higher, while TNFα and resistin lower among five patients re-examined after tumor resection. CONCLUSIONS: Among patients with an incidentally discovered pheochromocytoma, lower adiponectin, and higher resistin and TNFα levels may constitute additional factors for HT and DM. In our study, for the first time, correlations between incidentally discovered PHEO tumor size and concentrations of leptin as well as IL6 were found.
Selected issues of women's participation in labour market and on boards of family entreprises
- Anita Richert-Kaźmierska
2020
The chapter presents cultural determinants of roles attributed to women, as well as their situation in the labour market and in family businesses. The main aim of the study is to trace the changes in the social image of women’s roles in the labour market. The observations made are based on the changes in the value of the economic activity rate among women in the Baltic Sea Region (BSR) countries, as well as on the feminisation rate among managers, employees and successors of family businesses.
Selected local stability problems of channel section flanges made of aluminium alloys
- Marcin Kujawa
2020 Pełny tekst CONTINUUM MECHANICS AND THERMODYNAMICS
The paper addresses the issue of local buckling of compressed flanges of cold-formed thin-walled channel columns and beams with nonstandard flanges composed of aluminium alloys. The material behaviour follows the Ramberg–Osgood law. It should be noted that the proposed solution may be also applied for other materials, for example: stainless steel, carbon steel. The paper is motivated by an increasing interest in nonstandard cold-formed section shaping in local buckling analysis problems. Furthermore, attention is paid to the impact of material characteristics on buckling stresses in a nonlinear domain. The objective of the paper is to propose a finite element method (FEM) model and a relevant numerical procedure in ABAQUS, complemented by an analytical one. It should be noted that the proposed FEM energetic technique makes it possible to compute accurately the critical buckling stresses. The suggested numerical method is intended to accurately follow the entire structural equilibrium path under an active load in elastic and inelastic ranges. The paper is also focused on correct modelling of interactions between sheets of cross section of a possible contact during buckling analysis. Furthermore, the FEM results are compared with the analytical solution. Numerical examples confirm the validity of the proposed FEM procedures and the closed-form analytical solutions. Finally, a brief research summary is presented and the results are discussed further on.
Selection of C-Type Filters for Reactive Power Compensation and Filtration of Higher Harmonics Injected into the Transmission System by Arc Furnaces
- Andrzej, Grzegorz Lange
- Grzegorz Redlarski
2020 Pełny tekst ENERGIES
This article presents a method for selecting the elements of a C-type filter working with a conventional LC-type filter for compensating reactive power and filtering out higher harmonics generated by arc furnaces and ladle furnaces. The study was conducted in a steel mill supplied by a 110 kV transmission system, where higher harmonic currents and nonlinear loads were measured. A series of computer simulations were performed under various operating conditions, and an algorithm for selecting the parameters of a third-order C-type filter (for suppressing the second harmonic) and two second-order LC-type filters (for suppressing the third harmonic) was proposed. The filtering system was tested in an arc furnace with the highest rated power, and harmonics in the current spectrum were evaluated. The results of the measurements were used to analyze the effectiveness of the compensation system comprising two passive C-type and LC-type filters at different system configurations. C-type filters significantly influenced current harmonics. The influence of the changes in the number of arc furnace transformers on the true Root Mean Square (RMS) of the currents injected into the 110 kV transmission system and on the voltages of the 110 kV busbars was discussed.
Self-standing Nanoarchitectures
- Siuzdak Katarzyna
- Łukasz Haryński
- Jakub Wawrzyniak
- Piotr Kupracz
- Katarzyna Grochowska
2020 Pełny tekst
Despite there are structures invisible for the human eye, they mastered the world of advanced electronic devices, sensors, novel cosmetics or drugs. When the dimensions of the materials go down to the nanometres scale, their properties change dramatically comparing to the observable objects. Because of their tiny size, they gained the name of nanomaterials but simultaneously their importance has significantly grown up. Nanomaterials exhibit superb features such as a distinctive catalytic activity, hydrophobicity, photoconversion activity and biological affinity. Following that, even a small amount of nanomaterials is sufficient to provide unusual properties to the final products such as coatings, active layers in solar cells, clothes, electrodes and electrolytes used for energy storage devices. Owing to the rapid development in the synthesis methods and characterization techniques, especially those used for morphology inspection, we can investigate them in details on the molecular scale and describe the mechanism that stays behind improved antimicrobiological activity, hydrophobicity, capacitance or catalytic properties. Despite the number of usable elements is limited, the diversity of morphologies, namely rods, particles, tubes, planes and the possibility of heterostructures formation, provides researchers the wide room for maneuverer. Sometimes, only small change in the material geometry, structure or a little amount of introduced dopant atoms is enough to obtain completely new nanomaterial that has not been known so far. Therefore, we should not be surprised how fast surrounding environment is changing and our everyday life is supported by the novelties from the nano world. The aim of this chapter is to present the diversity of nanomaterials taking into account their dimensions, shape and composition. Herein, particles, tubes, wires, pores, walls, exhibiting at least one dimension within the nanoscale will be evoked. Moreover, the nanostructures that morphology reminds well known objects from nature are discussed. The description of some interesting examples is supported by the extraordinary SEM images illustrating the beauty unavailable for naked eye.
Self-Supervised Learning to Increase the Performance of Skin Lesion Classification
- Arkadiusz Kwasigroch
- Michał Grochowski
- Agnieszka Mikołajczyk
2020 Pełny tekst Electronics
To successfully train a deep neural network, a large amount of human-labeled data is required. Unfortunately, in many areas, collecting and labeling data is a difficult and tedious task. Several ways have been developed to mitigate the problem associated with the shortage of data, the most common of which is transfer learning. However, in many cases, the use of transfer learning as the only remedy is insufficient. In this study, we improve deep neural models training and increase the classification accuracy under a scarcity of data by the use of the self-supervised learning technique. Self-supervised learning allows an unlabeled dataset to be used for pretraining the network, as opposed to transfer learning that requires labeled datasets. The pretrained network can be then fine-tuned using the annotated data. Moreover, we investigated the effect of combining the self-supervised learning approach with transfer learning. It is shown that this strategy outperforms network training from scratch or with transfer learning. The tests were conducted on a very important and sensitive application (skin lesion classification), but the presented approach can be applied to a broader family of applications, especially in the medical domain where the scarcity of data is a real problem.
Sensor Position Estimation Method for IoT Using Mobile Reference Node
- Jacek Stefański
- Jarosław Sadowski
2020 Pełny tekst IEEE Access
The paper proposes an innovative method of locating objects for the Internet of Things (IoT). The proposed method allows the position of a fixed measuring sensor (MS) to be estimated using one mobile base station with a known position moving around the MS. The mathematical analysis of the method, and three algorithms — Newton’s (NA), gradient descent (GD) and genetic (GA) — for solving the system of non-linear positional equations are presented. Next, the analysis of the position dilution of precision (PDoP) parameter for the proposed method, and the Cramér-Rao lower bound (CRLB), limiting the accuracy of the method, are presented. Finally, the results of complex simulation studies on the efficiency of the proposed method for various selected system parameters of the sensor network and convergence of the algorithms used to solve the system of non-linear equations are described.
Sensorless five-phase induction motor drive with third harmonic injection and inverter output filter
- Patrick Strankowski
- Jarosław Guziński
- Marcin Morawiec
- Arkadiusz Lewicki
- Filip Wilczyński
2020 Pełny tekst Bulletin of the Polish Academy of Sciences-Technical Sciences
The paper presents a sensorless control approach for a five-phase induction motor drive with third harmonic injection and inverter output filter. In the case of the third harmonic injection being utilised in the control, the physical machine has to be divided into two virtual machines that are controlled separately and independently. The control system structure is presented in conjunction with speed and rotor flux observers that are required for a speed sensorless implementation of the drive. The last section is dedicated to experimental results of the drive system in sensorless operation, and the uninterrupted drive operation for two open-phase faults.
Sensorless Rotor Position Estimation of Doubly-Fed Induction Generator Based on Backstepping Technique
- Marcin Morawiec
- Krzysztof Blecharz
- Arkadiusz Lewicki
2020 IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
This paper proposes a speed observer algorithm for the sensorless control of a doubly-fed induction generator based on classical adaptive backstepping technique. The sensorless control is shown using classic stator field oriented control which is used to active and reactive power control. Performance of the proposed algorithm of a speed observer is validated by simulation and experimental results obtained using a small-rating generator and bidirectional voltage source converter. The stability analysis of the presented solution with regard to observer gains changes is also considered.
Service-based Resilience for Embedded IoT Networks
- Doganalp Ergenc
- Jacek Rak
- Mathias Fischer
2020
Embedded IoT networks are the backbone of safety-critical systems like smart factories, autonomous vehicles, and airplanes. Therefore, resilience against failures and attacks should be a prior concern already in their design stage. In this study, we introduce a service-based network model as an MILP optimization problem for the efficient deployment of a service overlay to the embedded network by meeting QoS and resilience requirements. We show the complexity and boundaries of the problem and propose several heuristics to relax the service deployment phase and increase the fault-tolerance against node and link failures. Our results indicate that the heuristics achieve results close to the optimum for small sizes of the problem with up to 10^8 time faster solution time. We also show that the heuristics can solve larger problem sizes and can maintain the service availability for 85% of all potential single node failures.
SERVICE-ORIENTED CYBERSPACE FOR IMPROVING CYBERSECURITY
- Henryk Krawczyk
2020 Pełny tekst TASK Quarterly
The paper presents a cyberspace model where different categories of IT services are offered and used largely. A general cybersecurity policy is considered and the corresponding cybersecurity strategies are shown. The role of such technologies as: Internet of Things, Cloud Computing and Big Data is analyzed in order to improve the cybersecurity of a cyberspace. A new kind of service oriented cyberspace is proposed and its main properties are emphasized. Two simple examples of such cyberspaces are given and briefly discussed.
Set of Experience and Decisional DNA: Experience-Based Knowledge Structures
- Cesar Sanin
- Edward Szczerbicki
2020
This chapter presents a description of Set of Experience Knowledge Structure (SOEKS) and Decisional DNA (DDNA), argumentation for a knowledge representation, composition, configuration and metrics. SOEKS is a combination of filtered and amalgamated information obtained from formal decision events. It facilitates effective explicit representation of decisional experience taken from different technologies. SOEKS comprises variables, functions, constraints and rules associated in a DNA shape, allowing the construction of enterprises’ fingerprints called Decisional DNA. SOEKS possesses characteristics that potentialize it as a more precise knowledge representation in a world guided by sensitive dependence and uncertainty, that is, SOEKS is a suitable representation for decisional explicit knowledge that has been gifted with capabilities to manage uncertainty, preciseness and incompleteness. Furthermore, SOEKS extends into the so-called DDNA due to the characterization and aggrupation of SOEKS into different classes termed decisional chromosomes. Such decisional chromosomes simulate specialized genes that when placed together create the decisional experience of an enterprise, the Decisional DNA.
SEWAGE SYSTEM CONCEPT FOR KAMIEŃ VILLAGE IN THE COMMUNE OF SZEMUD
- Dominika Grubba
2020
The aim of this thesis is to solve a disturbing problem, which is illegal sewage discharge, without any previous treatment in a village Kamień, Szemud commune, Poland, by developing a multivariate sewerage system concept. The introduction submits the theory concerning the division of sewer systems as well as the wastewater treatment’s level. Moreover, there is also the problem of rural sanitation presented and main locality – Kamień description. Furthermore, two variants of the sewage network, meaning: one, that is connecting to an existing network in the village and second one, that is discharging wastewater into the local sewage treatment plant are precisely defined. Calculation part presents all necessary steps to select sewagetubes and wastewater treatment plants. Lastly, there is also a graphic summary of entire solution for the village Kamień presented in this work.
Shading, Dusting and Incorrect Positioning of Photovoltaic Modules as Important Factors in Performance Reduction
- Ewa Klugmann-Radziemska
2020 Pełny tekst ENERGIES
The amount of solar radiation reaching the front cover of a photovoltaic module is crucial for its performance. A number of factors must be taken into account at the design stage of the solar installation, which will ensure maximum utilization of the potential arising from the location. During the operation of a photovoltaic installation, it is necessary to limit the shading of the modules caused by both dust and shadowing by trees or other objects. The article presents an analysis of the impact of the radiation reaching the surface of the radiation module on the efficiency obtained. Each of the analyzed aspects is important for obtaining the greatest amount of energy in specific geographical conditions. Modules contaminated by settling dust will be less efficient than those without deposits. The results of experimental studies of this effect are presented, depending on the amount of impurities, including their origins and morphologies. In practice, it is impossible to completely eliminate shadowing caused by trees, uneven terrain, other buildings, chimneys, or satellite dishes, and so on, which limits the energy of solar radiation reaching the modules. An analysis of partial shading for the generated power was also carried out. An important way for maximizing the incoming radiation is the correct positioning of the modules relative to the sun. It is considered optimal to position the modules relative to the light source, that is, the sun, so that the rays fall perpendicular to the surfaces of the modules. Any deviation in the direction of the rays results in a loss in the form of a decrease in the available power of the module. The most beneficial option would be to use sun-tracking systems, but they represent an additional investment cost, and their installations require additional space and maintenance. Therefore, the principle was adopted that stationary systems should be oriented to the south, using the optimal angle of inclination of the module surface appropriate for the location. This article presents the dependence of the decrease in obtained power on the angle of deviation from the optimal one.