2018 - Repozytorium publikacji - Politechnika Gdańska

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Computational aspects of greedy partitioning of graphs
- Piotr Borowiecki
2018 Pełny tekst JOURNAL OF COMBINATORIAL OPTIMIZATION
In this paper we consider a variant of graph partitioning consisting in partitioning the vertex set of a graph into the minimum number of sets such that each of them induces a graph in hereditary class of graphs P (the problem is also known as P-coloring). We focus on the computational complexity of several problems related to greedy partitioning. In particular, we show that given a graph G and an integer k deciding if the greedy algorithm outputs P-coloring with at least k colors is NP-complete if P is a class of Kp-free graphs with p>=3. On the other hand we give a polynomial-time algorithm when k is fixed and the family of minimal forbidden graphs defining the class P is finite. We also prove coNP-completeness of deciding if for a given graph G and an integer t>=0 the difference between the largest number of colors used by the greedy algorithm and the minimum number of colors required in any P-coloring of G is bounded by t. In view of computational hardness, we present new Brooks-type bound on the largest number of colors used by the greedy P-coloring algorithm.
Computational modeling of molecularly imprinted polymers as a green approach to the development of novel analytical sorbents
- Mariusz Marć
- Teobald Kupka
- Piotr Paweł Wieczorek
- Jacek Namieśnik
2018 Pełny tekst TRAC-TRENDS IN ANALYTICAL CHEMISTRY
The development of novel molecularly imprinted polymers (MIP) sorbents for specific chemical compounds require a lot of tedious and time-consuming laboratory work. Significant quantities of solvents and reagents are consumed in the course of the verification of appropriate configurations of polymerization reagents. Implementation of molecular modeling in the MIP sorbent development process appears to provide a solution to this problem. Appropriate simulations and computations facilitate the determination of the nature of interaction between the reagents and thus the selection of the best configuration of chemicals for the preparation of the sorbent. The article presents literature information on major computer software used for molecular modeling, its application in the development of MIP sorbents, as well as the advantages resulting from the implementation of computer-assisted techniques. The appropriate choice of polymerization reagents and conditions allows for a significant reduction of the adverse environmental impact of the entire laboratory process.
Computationally efficient two-objective optimization of compact microwave couplers through corrected domain patching
- Sławomir Kozieł
- Adrian Bekasiewicz
2018 Pełny tekst Metrology and Measurement Systems
Finding an acceptable compromise between various objectives is a necessity in the design of contemporary microwave components and circuits. A primary reason is that most objectives are at least partially conflicting. For compact microwave structures, the design trade-offs are normally related to the circuit size and its electrical performance. In order to obtain comprehensive information about the best possible trade-offs, multi-objective optimization is necessary that leads to identifying a Pareto set. Here, a framework for fast multi-objective design of compact micro-strip couplers is discussed. We use a sequential domain patching (SDP) algorithm for numerically efficient handling of the structure bandwidth and the footprint area. Low cost of the process is ensured by executing SDP at the low-fidelity model level. Due to its bi-objective implementation, SDP cannot control the power split error of the coupler, the value of which may become unacceptably high along the initial Pareto set. Here, we propose a procedure for correction of the S-parameters’ characteristics of Pareto designs. The method exploits gradients of power split and bandwidth estimated using finite differentiation at the patch centres. The gradient data are used to correct the power split ratio while leaving the operational bandwidth of the structure at hand intact. The correction does not affect the computational cost of the design process because perturbations are pre-generated by SDP. The final Pareto set is obtained upon refining the corrected designs to the high-fidelity EM model level. The proposed technique is demonstrated using two compact microstrip rat-race couplers. Experimental validation is also provided.
Computer Simulation in Predicting Biochemical Processes and Energy Balance at WWTPs
- Jakub Drewnowski
- Ewa Zaborowska
- Carmen Hernandez
2018 Pełny tekst E3S Web of Conferences
Nowadays, the use of mathematical models and computer simulation allow analysis of many different technological solutions as well as testing various scenarios in a short time and at low financial budget in order to simulate the scenario under typical conditions for the real system and help to find the best solution in design or operation process. The aim of the study was to evaluate different concepts of biochemical processes and energy balance modelling using a simulation platform GPS-x and a comprehensive model Mantis2. The paper presents the example of calibration and validation processes in the biological reactor as well as scenarios showing an influence of operational parameters on the WWTP energy balance. The results of batch tests and full-scale campaign obtained in the former work were used to predict biochemical and operational parameters in a newly developed plant model. The model was extended with sludge treatment devices, including anaerobic digester. Primary sludge removal efficiency was found as a significant factor determining biogas production and further renewable energy production in cogeneration. Water and wastewater utilities, which run and control WWTP, are interested in optimizing the process in order to save environment, their budget and decrease the pollutant emissions to water and air. In this context, computer simulation can be the easiest and very useful tool to improve the efficiency without interfering in the actual process performance.
Computing methods for fast and precise body surface area estimation of selected body parts
- Gustaw Rzyman
- Grzegorz Redlarski
- Aleksander Pałkowski
- Piotr Tojza
- Marek Krawczuk
- Janusz Siebert
2018
Currently used body surface area (BSA) formulas give satisfactory results only for individuals with typical physique, while for elderly, obese or anorectic people accurate results cannot be expected. Particularly noteworthy are the results for individuals with severe obesity (body-mass index greater than 35 kg/m2), for which BSA estimation errors reached 80%. The main goal of our study is the development of precise BSA models for specific body parts. We have achieved satisfactory results for a wide range of patients. Using regression models, such as: support vector regression, multilayer perceptron regressor, stochastic gradient descent, or ridge regression, a fourfold decrease in errors proportion is achieved. Machine learning algorithms led to reduction from 1.2 to 8 times for mean estimation error.
Conducting polymer films for biodegradable metallic cardiovascular stents
- Karolina Cysewska
- Piotr Jasiński
2018 Zeszyty Naukowe Wydziału ETI Politechniki Gdańskiej. Technologie Informacyjne
In recent years, there is increasing interest to create biodegradable metallic cardiovascular stents instead of using their permanent form. The most interesting materials for this purpose are iron and its alloys. However, in order to use it in clinical application, their degradation rate and biological performance need to be optimized. One promising solution is coating the metal with conducting polymer films. In this work, short overview of the use of the biodegradable iron and iron modified with polypyrrole as materials for cardiovascular stents is presented.
Conducting polymers for biodegradable metallic implants
- Karolina Cysewska
2018
Nowadays permanent metallic cardiovascular stents are long-term implants. The long-time presence of such an implant in human body can cause overgrowth of tissue within the treated portion of the vessel, blockage of the circulatory system and many other clinical complications, such as thrombosis, prolonged physical irritations or chronic inflammation. Therefore, in recent years, there is an interest to create biodegradable metallic cardiovascular stents. The materials for this purpose are active/oxidizable metals and their degradation is based on their progressive corrosion. One interesting metal for this application is iron. However, in order to use iron in clinical applications, its degradation rate and biological performance need to be optimized. A promising solution, proposed within the PhD project, is to modify the surface of the metal with conducting polymer film. Therefore, the main aim of the work is to investigate the conditions of the synthesis and degradation of polypyrrole (PPy) coated iron for use of the biodegradable cardiovascular metallic stent. The studies include: • Optimization procedure for corrosion resistance, surface analysis and electrical properties of PPy/Fe electrosynthesized in aqueous solution of pyrrole and sodium salicylate • Investigation of the electrochemical activity vs electrical properties of PPy/Fe material • Study of the electrochemical stability of PPy/Fe in aqueous solution of sodium salicylate • Investigation of the electrochemical synthesis of PPy on iron in aqueous solution of pyrrole and sodium salicylate studied in-situ by odd random phase electrochemical impedance spectroscopy. • Studies of the influence of the electropolymerization temperature on corrosion, morphological and electrical properties of polypyrrole film coated iron investigated in phosphate buffer saline solution at 37 °C • Degradation study of polypyrrole coated iron investigated by odd random phase electrochemical impedance spectroscopy in phosphate buffer saline solution at 37 °C The work presents the possibility of using PPy as coating on iron for possible medical applications. The performed electrochemical studies on PPy/Fe allows for detailed and reliable analysis of the material. The results obtained within the work open up new possibilities for PPy functional applications.
Connections between Mutually Unbiased Bases and Quantum Random Access Codes
- Edgar Aguilar Lozano
- Jakub Borkała
- Piotr Andrzej Mironowicz
- Marcin Pawłowski
2018 PHYSICAL REVIEW LETTERS
We present a new quantum communication complexity protocol, the promise--Quantum Random Access Code, which allows us to introduce a new measure of unbiasedness for bases of Hilbert spaces. The proposed measure possesses a clear operational meaning and can be used to investigate whether a specific number of mutually unbiased bases exist in a given dimension by employing Semi--Definite Programming techniques.
Constructing autonomous agents using the cognitive-emotional architecture of the mind
- Zdzisław Kowalczuk
- Michał Czubenko
2018
The article discusses an important issue regarding the humanoid aspects of modern science related to the autonomy of systems and robotization. Particular attention is paid to the basic aspects of cognitive architecture. After a short introduction, the Intelligent Decision Making System, developed at the ETI Faculty of the Gdańsk University of Technology, is described.
Constructing genuinely entangled multipartite states with applications to local hidden variables and local hidden states models
- Remigiusz Augusiak
- Maciej Demianowicz
- J. Tura
2018 Pełny tekst PHYSICAL REVIEW A
Building upon the results of R. Augusiak et al. [Phys. Rev. Lett. 115, 030404 (2015)] we develop a general approach to the generation of genuinely entangled multipartite states of any number of parties from genuinely entangled states of a fixed number of parties, in particular, the bipartite entangled ones. In our approach, certain isometries whose output subspaces are either symmetric or genuinely entangled in some multipartite Hilbert spaces are applied to local subsystems of bipartite entangled or multipartite genuinely entangled quantum states. To prove that entanglement of the resulting states is indeed genuine we then introduce criteria allowing us to decide it efficiently. The construction is then exploited to provide examples of multipartite states that are genuinely entangled but not genuinely nonlocal, giving further illustration for the inequivalence between entanglement and nonlocality in the multiparticle scenario. It is also shown how to construct genuinely entangled states which are unsteerable across certain bipartite cuts
CONTEMPORARY APPROACH TOWARDS RESPONSIVE ARCHITECTURE
- Jan Cudzik
2018
Constantly changing environment pressures every living for a change, and response becomes a basic reaction of any living form. Change is a natural reaction that enables survivor of all the species. However, in architecture, the responsive structure did not take important role until the twentieth century. During that time many concepts and building introduced kinematics into the discipline. In the late 50 and 60 of XX century, visionary architects introduced responsive and partly autonomous structure. Designers like Constant Nieuwenhuis, Cedric Price were searching for new architectural solutions. The projects like Fun Palace were at the time, when they were created, impossible to develop due to technical matters and therefore remained just bold visions for the future. However, the new approach towards architectural design opened the discipline into new spatial solution, that later became more and more relevant in contemporary architecture. In the process of developing contemporary responsive kinematic architecture historical conceptual designs from the second half of the twentieth century take a significant role. It will be proved that development of responsive architecture is based on the conceptual designs starting from the twentieth century.
CONTEMPORARY ART AND CIVIC ENGAGEMENT
- Joanna Kabrońska
2018
The paper aims to explore the potential role of contemporary art as a catalyst for social transformation and civic engagement. The research focuses on the visual arts and their power to change social attitudes in contemporary society. On the basis of theoretical, transdisciplinary approaches and analysis of artwork the paper investigates emerging forms of art and how they address pressing social issues and concerns that would otherwise remain unfamiliar. Artwork that reveals social phenomena and trends lying hidden under the surface of social reality are—in a sense—only exist thanks to the reaction of the audience. The research provides insights both into the art practices developed through relationships with communities and their social impact. The text concludes with an attempt to present various art practices understood as discursive animations of public spaces. The research findings offer the opportunity to introduce new interpretations of the complex and difficult relation between art and society to the contemporary academic discourse. The text stresses that today the study of art phenomena would be difficult without transdisciplinary approaches. There is a need for further research, but the paper confirms the potential of this direction of study.
Context-aware User Modelling and Generation of Recommendations in Recommender Systems
- Aleksandra Karpus
2018 Pełny tekst
Recommender systems are software tools and techniques which aim at suggesting new items that may be of interest to a user. This dissertation is focused on four problems in recommender systems domain. The first one is context-awareness, i.e. how to obtain relevant contextual information, how to model user preferences in a context and use them to make predictions. The second one is multi-domain recommendation, which aim at suggesting items from many domains using user ratings from all of them. The third one is new user cold-start problem which occurs when a new user registers into a recommender system. He will not receive interesting recommendations just because the system does not know his preferences yet. The last problem is the need of generating explanations on how recommender system works. Two contextual user models and appropriate recommendation algorithms were proposed. First model is based on existing SIM method. The ontology-based contextual pre-filtering technique associated with the model allows dynamic generalization of contextual parameters values and generation of multi-domain recommendations. The second model consists of contextual conditional preferences. The post-filtering method associated with it, which is called re-rankCCP, allows to generate explanations for users and contextual recommendations in new user cold-start situations as well as in typical scenarios.
Contextual Knowledge to Enhance Workplace Hazard Recognition and Interpretation in a Cognitive Vision Platform
- Caterine De
- Cesar Sanin
- Edward Szczerbicki
2018 Pełny tekst
The combination of vision and sensor data together with the resulting necessity for formal representations builds a central component of an autonomous Cyber Physical System for detection and tracking of laborers in workplaces environments. This system must be adaptable and perceive the environment as automatically as possible, performing in a variety of plants and scenes without the necessity of recoding the application for each specific use. But each recognition system has its own inherent limits, especially those which task is to work in unidentified environments and deal with unknown scenarios and specifications. The platform described in this paper takes this into account by connecting the probabilistic area of event detection with the logical area of formal reasoning in a Cognitive Vision Platform for Hazard Control (CVP-HC). In order to support formal reasoning, additional relational scene information is supplied to the recognition system. In this platform, the contextual knowledge is used to improve the recognition and interpretation of detected events. This relational data together with all collected information is represented explicitly as a Set of Experience Knowledge Structure (SOEKS), categorized and stored as a Decisional DNA (DDNA), a decisional safety fingerprint of a company. By these means, the systems assesses and addresses critical unsafe behaviors whilst gives support to an explicit long term culture change process. By the use of context the CVP-HC is capable adjust accordingly without the need of rewriting the application’s code every time conditions or specifications changes.
CONTROL OF THE WAVES IN A TOWING TANK WITH THE USE OF A BLACK-BOX MODEL
- Marcin Drzewiecki
2018 Pełny tekst Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
The paper describes an adaptive control system of the waves, implemented in the Ship Design and Research Centre, CTO S.A. The purpose of generating the waves in the towing tank is the modelling of the environmental conditions during hydrodynamic model tests. The tests are performed on scale models of towed or free running ships, anchored structures like oil rigs or bottommounted structures, e.g. wind turbines. In the towing tank of CTO S.A., the waves are generated using a flap-type wavemaker with hydraulic drive. The adaptive control system includes gain scheduling and Black-Box model. It has been developed and implemented using the 32-bit embedded system and computer application (C#.NET). The Black-Box model was proposed as a simple solution allowing compensating the hydromechanical phenomena affecting the generated waves, i.e. disintegration, reflection, damping and nonlinear energy transfer. The solution proved to be sufficient to generate required wave spectra with expected accuracy in a user-friendly manner.
Convenient and Efficient Diastereoselective Preparation of Functionalized Z -Alkenyl Sulfides
- Justyna Doroszuk
- Mateusz Musiejuk
- Łukasz Ponikiewski
- Dariusz Witt
2018 Pełny tekst EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
We have developed an efficient and convenient regio‐ and stereoselective reduction of the alkynyl sulfides with pinacolborane in the presence of copper(I) chloride to produce (Z)‐alkenyl sulfides in good and very good yields. The functionalized alkynyl sulfides are readily available based on the reaction of lithium acetylides with thiotosylates under mild conditions.
Convenient and efficient synthesis of functionalized unsymmetrical Z-alkenyl disulfanes
- Mateusz Musiejuk
- Justyna Doroszuk
- Dariusz Witt
2018 Pełny tekst RSC Advances
We developed a simple and efficient method for the synthesis of functionalized unsymmetrical Z-alkenyl disulfanes under mild conditions in moderate to good yields. The designed method is based on the reaction of Z-alkenyl thiotosylates with thiols in the presence of base. The developed method allows the preparation of unsymmetrical Z-alkenyl disulfanes bearing additional hydroxy, carboxy, or amino functionalities.
Conversion of Biomass and Municipal Wastes into Syngas and Hydrogen using Highly Preheated Agent (HTAG)
- Jan Stąsiek
- Marcin Jewartowski
2018
Gasification is considered to be one of the most promising energy recovery technologies for the widespread utilization of biomass and wastes. During this process raw feedstock is converted into a combustible gas, which can then be burnt to produce thermal energy, or to run engines for mechanical or electrical power. The studies of biomass gasification demonstrate it as a friendly alternative to fossil fuels as one of renewable energy targets. High Temperature Air/Steam Gasification (HTAG) concept is proposed as a combination of direct and indirect gasification as an alternative approach for direct burning of biomass. It has been applied in performing extensive studies on thermal conversion of biomass and wastes into fuel and electricity over two decades in Japan, USA, Germany, Netherlands, Greece and Sweden. Study of thermal conversion of biomass and wastes was also conducted since year 2001 at Gdansk University of Technology (GUT) in Poland. Therefore the goal of this paper is to demonstrate this technology to produce syngas and hydrogen.
Cooperation of mono- and bi-articular muscles: human lower limb
- Bartłomiej Zagrodny
- Michał Ludwicki
- Wiktoria Wojnicz
- Jerzy Mrozowski
- Jan Awrejcewicz
2018 Pełny tekst JOURNAL OF MUSCULOSKELETAL & NEURONAL INTERACTIONS
Objectives: The aim of this study was to create and analyze a Pareto-optimal problem that would describe cooperation between mono- and bi-articulate lower limb muscles in sagittal plane. Methods: Equations describing the problem were derived and analyzed, additional constrains were introduced and experimental verification based on gait video analysis was performed. Results: Uncertainty of Pareto-optimal solution is shown for the muscular-skeletal system. An explanation of this situation is presented and discussed. Moreover, this theoretical observation is compared with a lack of gait reproducibility. Small but noticeable differences in gait cycles are shown and explained. Conclusions: A muscular system redundancy is shown and explained by the meaning of Pareto problem. Theoretical considerations were confirmed through a gait analysis. This leads to the conclusion, that during muscle cooperation each movement cycle can be different from the previous one, however due to physiological restrictions only a narrow equivalence class of the possible solutions exists.
Copper-based 2D-coordination polymer as catalyst for allylation of aldehydes
- Gilson Da_silva
- Paulo Menezes
- Ivani Malvestiti
- Eduardo H. L. Falcão
- Severino Alves Junior
- Jarosław Chojnacki
- Fausthon F. da Silva
2018 Pełny tekst JOURNAL OF MOLECULAR STRUCTURE
A copper-tartrate, [Cu2(Tart)2(H2O)2]·4H2O, was synthesized at room temperature in aqueous media using copper chloride and D-tartaric acid. The compound crystallizes in the monoclinic system P21 space group and was characterized by infrared spectroscopy, thermogravimetry, X-ray powder diffraction and the results are in good agreement with the single crystal structure. Catalytic properties for allylation of aldehydes were investigated at different solvents, and the best conditions obtained were using a mixture of CH2Cl2:H2O. The copper-tartrate obtained showed good performance as catalyst for different substrates and yields were between 62% and 95%