9 results on '"Krzysztof Wiktorowicz"'
Search Results
2. Combined Regularized Discriminant Analysis and Swarm Intelligence Techniques for Gait Recognition
- Author
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Tomasz Krzeszowski and Krzysztof Wiktorowicz
- Subjects
gait recognition ,biometrics ,regularized discriminant analysis ,particle swarm optimization ,grey wolf optimization ,whale optimization algorithm ,Chemical technology ,TP1-1185 - Abstract
In the gait recognition problem, most studies are devoted to developing gait descriptors rather than introducing new classification methods. This paper proposes hybrid methods that combine regularized discriminant analysis (RDA) and swarm intelligence techniques for gait recognition. The purpose of this study is to develop strategies that will achieve better gait recognition results than those achieved by classical classification methods. In our approach, particle swarm optimization (PSO), grey wolf optimization (GWO), and whale optimization algorithm (WOA) are used. These techniques tune the observation weights and hyperparameters of the RDA method to minimize the objective function. The experiments conducted on the GPJATK dataset proved the validity of the proposed concept.
- Published
- 2020
- Full Text
- View/download PDF
3. The Use of Artificial Neural Networks in Supporting the Annual Training in 400 meter Hurdles
- Author
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Janusz Iskra, Krzysztof Przednowek, Krzysztof Wiktorowicz, and Tomasz Krzeszowski
- Subjects
400 meter hurdles ,artificial neural networks ,planning training loads ,Sports ,GV557-1198.995 ,Sports medicine ,RC1200-1245 ,Physiology ,QP1-981 - Abstract
This paper presents an evaluation of the annual cycle for 400 m hurdles using artificial neural networks. The analysis included 21 Polish national team hurdlers. In planning the annual cycle, 27 variables were used, where 5 variables describe the competitor and 22 variables represent the training loads. In the presented solution, the task of generating training loads for the assumed result were considered. The neural models were evaluated by cross-validation method. The smallest error was obtained for the radial basis function network with nine neurons in the hidden layer. The performed analysis shows that at each phase of training the structure of training loads is different.
- Published
- 2017
- Full Text
- View/download PDF
4. The phthalocyanines applications in photodynamic therapy investigated by time-resolved and steady-state photothermal methods
- Author
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Danuta Frackowiak, Krzysztof Wiktorowicz, Alfons Planner, Aneta Waszkowiak, and Rodica-Mariana Ion
- Subjects
Renewable energy sources ,TJ807-830 - Abstract
The time-resolved photothermal methods are used in order to establish the yield of intersystem (singlet-triplet) crossing of dyes that are candidates for the application in photodynamic therapy. It is known that molecules with long living triplet state cause efficient photosensitization by direct interaction with the cells or by singlet oxygen generation.
- Published
- 2002
- Full Text
- View/download PDF
5. The role of viruses in the cancerogenesis
- Author
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Michał Chojnicki, Mariola Pawlaczyk, Celina Helak-Łapaj, Jakub Żurawski, and Krzysztof Wiktorowicz
- Subjects
cancers ,cancerogensis ,viruses ,Medicine - Abstract
It is estimated that seven key viruses such as Hepatitis B virus (HBV), Hepatitis C virus (HCV), Human T-lymphotropic virus (HTLV), Human papilloma viruses (HPV), Kaposi’s sarcoma-associated herpes-virus (KSHV), Epstein-Barr virus (EBV) and Merkel cell polyomavirus (MCV), are responsible for about 11% of cancers all over the world. Viruses however are not only associated with cancerogenesis process. Scientific researches from recent years emphasize the possible use of the microorganisms as antitumor therapy. Oncoviruses, also defined as tumor viruses cause cancers whereas oncolytic viruses infect the host’s cancer cells leading to destruction of tumor and due to that they are described as cancer killing viruses. It offers the potential application of viral infections to the cancer therapy.
- Published
- 2014
- Full Text
- View/download PDF
6. The effect of cigarette smoking on the clinical course of inflammatory bowel disease
- Author
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Barbara Poniedziałek, Krzysztof Wiktorowicz, Piotr Rzymski, Jacek Karczewski, Zygmunt Adamski, and Anna Rychlewska-Hańczewska
- Subjects
medicine.medical_specialty ,Crohn's disease ,Original Paper ,business.industry ,Gastroenterology ,Clinical course ,Disease ,medicine.disease ,Former Smoker ,Inflammatory bowel disease ,Ulcerative colitis ,smoking ,Surgery ,inflammatory bowel disease ,Internal medicine ,medicine ,Medical history ,Risk factor ,business ,ulcerative colitis - Abstract
Introduction: Cigarette smoking is considered an important risk factor for developing Crohn’s disease (CD), contributing to a more severe course of the disease. Conversely, smoking is believed to have a beneficial effect on the course of ulcerative colitis (UC), a second major condition of inflammatory bowel disease (IBD). Aim: To investigate the effect of tobacco use on the clinical course of IBD. Material and methods: A group of 95 adults with IBD were enrolled to the study. Demographic and clinical data of patients as well as their smoking status were analysed based on their medical history. Values were considered significant when p ≤ 0.05. Results: Current smokers constituted the majority of CD patients. They tended to develop a more severe course of the disease, compared to former smokers and non-smokers. Current smokers suffered a moderate-to-severe form of the disease and required immunosuppressive therapy more frequently. They were also hospitalised and underwent surgeries more frequently than patients from other investigated subgroups. The study failed, however, to fully confirm the beneficial effect of smoking on the clinical outcome of UC. The investigated non-smokers and former smokers suffered a more severe disease, but the analysis did not find any statistical differences in the frequencies of hospitalisations nor immunosuppressant usage among the investigated subgroups. Conclusions: The study confirmed a detrimental effect of smoking on the outcome of CD, but failed to fully confirm its beneficial effect on UC.
- Published
- 2014
7. Predictive Modeling in Race Walking
- Author
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Tomasz Krzeszowski, Krzysztof Przednowek, Lesław Lassota, and Krzysztof Wiktorowicz
- Subjects
General Computer Science ,Article Subject ,Computer science ,General Mathematics ,Structure (category theory) ,Walking ,Machine learning ,computer.software_genre ,lcsh:Computer applications to medicine. Medical informatics ,lcsh:RC321-571 ,Race (biology) ,Quadratic equation ,Lasso regression ,Humans ,lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry ,business.industry ,General Neuroscience ,Multivariable calculus ,Linear model ,Process (computing) ,General Medicine ,Nonlinear system ,Nonlinear Dynamics ,Athletes ,Linear Models ,lcsh:R858-859.7 ,Neural Networks, Computer ,Artificial intelligence ,business ,computer ,Algorithms ,Research Article - Abstract
This paper presents the use of linear and nonlinear multivariable models as tools to support training process of race walkers. These models are calculated using data collected from race walkers’ training events and they are used to predict the result over a 3 km race based on training loads. The material consists of 122 training plans for 21 athletes. In order to choose the best model leave-one-out cross-validation method is used. The main contribution of the paper is to propose the nonlinear modifications for linear models in order to achieve smaller prediction error. It is shown that the best model is a modified LASSO regression with quadratic terms in the nonlinear part. This model has the smallest prediction error and simplified structure by eliminating some of the predictors.
- Published
- 2015
8. The role of viruses in the cancerogenesis
- Author
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Krzysztof Wiktorowicz, Michał Chojnicki, Celina Helak-Łapaj, Mariola Pawlaczyk, and Jakub Żurawski
- Subjects
Hepatitis B virus ,biology ,business.industry ,Hepatitis C virus ,viruses ,Merkel cell polyomavirus ,virus diseases ,biology.organism_classification ,medicine.disease_cause ,Virology ,Virus ,Oncolytic virus ,Tumor Virus ,medicine ,cancers ,cancerogensis ,Medicine ,Virotherapy ,business ,Oncovirus - Abstract
It is estimated that seven key viruses such as Hepatitis B virus (HBV), Hepatitis C virus (HCV), Human T-lymphotropic virus (HTLV), Human papilloma viruses (HPV), Kaposi’s sarcoma-associated herpes-virus (KSHV), Epstein-Barr virus (EBV) and Merkel cell polyomavirus (MCV), are responsible for about 11% of cancers all over the world. Viruses however are not only associated with cancerogenesis process. Scientific researches from recent years emphasize the possible use of the microorganisms as antitumor therapy. Oncoviruses, also defined as tumor viruses cause cancers whereas oncolytic viruses infect the host’s cancer cells leading to destruction of tumor and due to that they are described as cancer killing viruses. It offers the potential application of viral infections to the cancer therapy.
- Published
- 2014
9. Biosimilars in dermatology.
- Author
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Mazur M, Olek-Hrab K, Karczewski J, Teresiak-Mikołajczak E, and Adamski Z
- Abstract
Over the last decade the availability of biological drugs for the treatment of psoriasis vulgaris, psoriatic arthritis and many other inflammatory diseases has revolutionized the treatment of these diseases around the world. Due to the high cost of therapy, the search has started for biosimilars. In dermatology the greatest interest in biosimilar medicines concerns inhibitors of tumor necrosis factor a (TNF-α), for use in the treatment of psoriasis vulgaris and psoriatic arthritis (infliximab, etanercept, adalimumab). The most important element of the safety of biologicals is their immunogenicity. Therefore, when discussing biosimilars, attention needs to be paid to the dangers of their immune activity. In view of the fact that the drugs contain and aggregates, produced by living organisms or cultures of living cells, they cannot be compared in any way to low molecular weight synthetic generics (called generics). Biosimilars are authorized for use in patients and treated as equivalent to the reference medicine only after passing a number of studies and assessments. As it is well known, the development of medicine and pharmacology is extremely intense, and the market in biological medicine is developing much faster than that of all other drugs, which underlines their important role in modern medicine. Currently, the subject of biosimilars is one of the most important challenges and topics of discussion around the world, including pharmacovigilance and legal and economic regulatory standards. It seems inevitable that biosimilar products will be introduced for the treatment of diseases with indications corresponding to the original product on which they are based.
- Published
- 2015
- Full Text
- View/download PDF
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