Wyniki wyszukiwania - BazTech

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Long-term comparative effects of the covid-19 pandemic on supply chains in Poland, Georgia and Turkey

Sikora Marek, Kikoria Giga, Sanikidze Zezva, Çetingüç Başak, Rybacka Oliwia

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

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2024

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z. 193

463--487

EN

Purpose: This paper explores the enduring repercussions of the COVID-19 pandemic on global supply chains by investigating the experiences and adaptations of organizations in Poland, Georgia, and Turkey. It seeks to provide valuable insights into the long-term implications of the pandemic on supply chain management, with a focus on strategies and challenges faced by businesses in different regions. Design/Methodology/Approach: We conducted an extensive study utilizing an online questionnaire to gather primary data from a diverse sample of organizations in Poland, Georgia, and Turkey. This research approach is quantitative and comprehensively assess the pandemic's impact on supply chains. We analysed responses from a range of industries, enabling a holistic understanding of the topic. In addition to descriptive analysis, we conducted a comparative examination of the three countries using ANOVA (Analysis of Variance) to assess any significant differences among them. Furthermore, we employed Cramér's V, a robust statistical measure, to investigate associations between categorical variables within the dataset Findings: The research reveals that the outcomes in three distinct countries are surprisingly similar, contrary to initial expectations. The majority of the proposed COVID-19 factors exhibit no statistically significant distinctions among Poland, Georgia, and Turkey. Consequently, we can infer that the COVID-19 pandemic exerted a considerable and widespread impact on the entities under consideration. Research Limitations: Despite our efforts to gather a representative sample, the study may not encompass all industries and organizations equally. Additionally, the research is subject to the limitations of self-reported data and potential bias in responses. The focus on specific regions may not capture the entirety of global supply chain dynamics. Practical Implications: This research provides practical insights for organizations navigating supply chain challenges in a post-pandemic world. It offers guidance on building resilient and adaptable supply chains and managing risks effectively. Businesses can use these insights to make informed decisions and enhance their supply chain strategies. Originality/Value: Drawing from our own research conducted in three countries after the official conclusion of the pandemic, this study adds a distinctive contribution to the current body of literature. It takes a long-term perspective on the repercussions of the COVID-19 pandemic on supply chains, specifically emphasizing diverse regions. The employed methodology and regional comparisons offer a nuanced insight into the dynamic evolution of the supply chain landscape, underscoring the importance of adaptability and resilience. In contrast to various studies conducted at the onset and during the pandemic, this paper uniquely seeks to discern the enduring effects.

2

Competition on the courier, express and postal services market

Sikora Marek

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

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2024

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z. 193

489--512

EN

Purpose: The purpose of the publication is to conduct a comprehensive analysis of the courier services market (CEP) in Poland. The research focuses on identifying the main players in the market, understanding their operating strategies and assessing the impact of innovative solutions on the market. In addition, the aim is to examine the competitive advantages of companies against the background of customer satisfaction levels, the way courier services are delivered, and to analyse innovations in logistics. Design/methodology/approach: The surveys were conducted in three stages in 2020, 2021, and 2022/2023 in the Bydgoszcz metropolitan area. Conducting the surveys in three stages in different years made it possible to analyse changes over time and the mixed methodology using both online (CAWI) and face-to-face (PAPI) surveys allowed us to reach a wider group of respondents. Findings: Pandemic COVID-19 has increased the use of courier services. The current market leader is InPost and the high level of customer satisfaction is due to innovative parcel machines, speed of delivery and convenience of tracking parcels. Research shows that courier company customers value timeliness, efficiency and modern solutions such as parcel machines, which is an important area for courier companies to focus on in their quest for customer satisfaction and loyalty. Research limitations/implications: The results of the study are not representative, but they may be a contribution to a broader and more in-depth analysis of the KEP market and the level of customer satisfaction of courier companies. The limitations of the study include the limited geographical area (Bydgoszcz conurbation) and the small representativeness of the sample, which may affect the generalisation of the results. Research conducted on a larger scale, taking into account different regions of Poland, would provide a more complete picture of the courier services market. Practical implications: The increase in the use of courier services during the pandemic indicates changes in shopping behaviour. It was also found that older people are less likely to use courier services for online purchases, suggesting the need to educate and adapt offers to this customer group. Courier companies should therefore focus on improving service quality, offering innovative delivery solutions, adapting to changing customer preferences and responding flexibly to changing market conditions.Originality/value: The article provides information that can be used to make strategic decisions, tailor services to meet customer needs, increase the company's competitiveness in the CEP market, and build a strong reputation based on actual customer preferences.

3

Entering the labour market: an empirical analysis in Poland and Georgia

Kikoria Giga, Sikora Marek, Sanikidze Zezva

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

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2023

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z. 173

315--328

EN

Purpose: The purpose of this paper is to observe and describe undergraduates entering the labour market in Poland and in Georgia and fill the gaps in the literature. Design/methodology/approach: The study uses a structured and self-administered online questionnaire. The population of the Bydgoszcz University of Science and Technology, in Poland was 900 active students, and the students of the Tbilisi State University - 4460. Cramér's V was used to check the association between different variables. The questionnaire is in line with the International Labour Organization and the National Statistics Office of Georgia methodology. Findings: The study shows us that the results of two different countries are not as far apart as it would have to be supposed, but Georgian and Polish education system differ toward connection to the labour market. Research limitations/implications: The study uses a short period to collect the data and a small sample. Another limitation of the study is the non-coincidence of the Education System in Poland and Georgia. Moreover, the limitation that may arise is the use of Email surveys that have several limitations, primarily being that they can appear dry and uninteresting. Practical implications: The study can be used by regulators, researchers, scientists, public institutions, and Governments. Originality/value: This is one of the first attempts to analyse data from Poland and Georgia and focuses on undergraduates. The article aims to determine whether there is an association between specific variables. The authors believe that this paper will gain some attention from policymakers and can allow Governments to take action.

4

The use of managerial dashboards in manufacturing companies

Dzieża Grzegorz, Sikora Marek

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

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2022

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z. 156

157--168

EN

Purpose: The aim of the publication is to diagnose the level and to assess the possibility of using managerial dashboards created in an Excel spreadsheet to supervise management processes in enterprises. Design/methodology/approach: The research developed the method of a directed interview with the staff at various management levels. The supervision of technological processes, economic analysis, and the provision of broadly understood services for citizens have been the subject of the research. Findings: Managers show little interest in improving their employees' analytical skills. Training in this area is not planned and the impact of analytical capabilities of the tools available for the functioning of the company are not appreciated. Research limitations/implications: The results of the research are not representative, but they encourage the authors to carry out a broader and more in-depth analysis of the existing situation in enterprises. Practical implications: The research shows the need to rationalize human resources management. This process requires an increased supervision over employee development planning with the use of the appropriate training. This may have a significant impact on efficient management and, consequently, on the company's financial results. Originality/value: The article is to be an element stimulating the management to more thoughtful activities in the field of selection, training, and use of personnel at various levels of management in the company.

5

The DSO Network Development with the Increase of Distributed Energy Resources Number and Their Capacity

Mataczyńska Ewa, Sikora Marek

Energy Policy Studies

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2022

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No. 2 (10)

27--40

EN

Energy transition is a continuous process, involving all elements of the energy sector. For Distribution System Operators the ability to cope with new challenges resulting from the energy transition (i.a. digitalisation, EV, PV, energy storage, distributed energy, energy communities, microgrids, energy sharing, geopolitical changes) is one of the most significant elements of this process. To meet the challenges of the transformation, it is necessary to develop new solutions adapted to the needs of all market participants, redefine priorities, establish new rules of cooperation in order to ensure security and stability of the power system at economically justified costs. The article describes network flexibility as a tool allowing DSOs meet needs of energy sector transformation process based on flow-circle concept. The idea of it is to use continuous observation tools (captured in the observability of the network), making predictions over different time horizons, across different areas, with varying observation granularity. The result of the calculations allows to identify constraints in the system, e.g., overloads, risk of failure or shortage of power or energy, and to select countermeasures commensurate with the threat and available at the selected time horizon.

6

Rule-based approximation of black-box classifiers for tabular data to generate global and local explanations

Maszczyk Cezary, Kozielski Michal, Sikora Marek

Annals of Computer Science and Information Systems

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2022

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Vol. 30

89--92

EN

The need to understand the decision bases of artificial intelligence methods is becoming widespread. One method to obtain explanations of machine learning models and their decisions is the approximation of a complex model treated as a black box by an interpretable rule-based model. Such an approach allows detailed and understandable explanations to be generated from the elementary conditions contained in the rule premises. However, there is a lack of research on the evaluation of such an approximation and the influence of the parameters of the rule-based approximator. In this work, a rule-based approximation of complex classifier for tabular data is evaluated. Moreover, it was investigated how selected measures of rule quality affect the approximation. The obtained results show what quality of approximation can be expected and indicate which measure of rule quality is worth using in such application.

7

Demand forecasting in the fashion business — an example of customized nearest neighbour and linear mixed model approaches

Henzel Joanna, Wawrowski Łukasz, Kubina Anna, Sikora Marek, Wróbel Łukasz

Annals of Computer Science and Information Systems

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2022

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Vol. 30

61--65

EN

The fashion industry is characterised by the need to make demand forecasts in advance and for highly volatile products for which we often have no sales history at the time the forecasts are made. For this reason, it is necessary to propose forecast mechanisms that can cope with the given conditions. Such forecasts can be based on expert predictions for generalized product categories. In this case, the task of machine learning forecasting methods would be to divide the aggregate prediction into forecasts for individual products, in each colour and size. In the paper, we present several approaches to this specific task. We present the use of the naive method, custom nearest neighbour approach, parametric linear mixed model and an ensemble approach. Overall, the best results we obtained for the ensemble method. Our research was based on real data from fashion retail.

8

Outline of using the Energy Cluster potential for the Distribution System Operator

Sikora Marek

Energy Policy Studies

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2021

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No. 2 (8)

3--12

EN

The aim of the article is to present the possibility of cooperation between the Energy Cluster and Distribution System Operator (DSO) in order to improve the local grid operation, and indirectly, for the benefit of the National Power System. The possibility of creation and operation energy clusters in Poland, with particular emphasis on contractual relations with the DSO and the position of the cluster in the energy market is discussed at the first stage of the article. The following part analyses the impact of distributed energy sources (DER) on the distribution grid as well as the grid operation problems. The issue of distribution grid flexibility in relation to the development of distributed generation is presented. What is more the possible interactions between the Energy Cluster and the DSOs in this respect is elaborated. Finally, the ways of using the energy potential of the Energy Cluster by the DSOs is analysed, which take the form of specialized services for grid operators.

9

Enhancement of COVID-19 symptom-based screening with quality-based classifier optimisation

Kozielski Michał, Henzel Joanna, Tobiasz Joanna, Gruca Aleksandra, Foszner Paweł, Zyla Joanna, Bach Małgorzata, Werner Aleksandra, Jaroszewicz Jerzy, Polańska Joanna, Sikora Marek

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2021

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Vol. 69, nr 4

art. no. e137349

EN

Efforts of the scientific community led to the development of multiple screening approaches for COVID-19 that rely on machine learning methods. However, there is a lack of works showing how to tune the classification models used for such a task and what the tuning effect is in terms of various classification quality measures. Understanding the impact of classifier tuning on the results obtained will allow the users to apply the provided tools consciously. Therefore, using a given screening test they will be able to choose the threshold value characterising the classifier that gives, for example, an acceptable balance between sensitivity and specificity. The presented work introduces the optimisation approach and the resulting classifiers obtained for various quality threshold assumptions. As a result of the research, an online service was created that makes the obtained models available and enables the verification of various solutions for different threshold values on new data.

10

Impact of time series clustering on fuel sales prediction results

Henzel Joanna, Sikora Marek, Bularz Jakub

Annals of Computer Science and Information Systems

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2021

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Vol. 26

13--21

EN

The purpose of the paper is to check the impact of data clustering in the process of predicting demand. We checked different ways of adding information about similar datasets to the forecasting process and we grouped the measurements in multiple ways. The experiments were executed on 50 time series describing fuels sales (gasoline and diesel sales) on 25 petrol stations from an international company. We described the data preparation process and feature extraction process. In the 9 presented experiments, we used the XGBoost algorithm and some typical time series forecasting methods (ARIMA, moving average). We showed a case study for two datasets and we discussed the practical usage of the tested solutions. The results showed that the solution which used XGBoost model utilising data gathered from all available petrol stations, in general, worked the best and it outperformed more advanced approaches as well as typical time series methods.

11

Performance Analysis of Dynamic PUCCH Allocation Algorithm in LTE Network

Czerniecki Maciej, Wszołek Jacek, Sikora Marek, Ludwin Wiesław

International Journal of Electronics and Telecommunications

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2020

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Vol. 66, No. 1

211--216

EN

The aim of the presented paper was to verify the impact of Dynamic PUCCH Resource Allocation Algorithm of the LTE cellular system on the maximum uplink cell throughput and call setup success rate - CSSR. Paper includes the laboratory testbed description and presents the results of an experiment confirming the improvement of both key performance indicators KPIs. Apart from the presentation of the Dynamic PUCCH Resource allocation algorithm, the paper also includes a description of legacy LTE uplink (PUCCH and PUSCH) channels dimensioning process thus filling the gap of such a tutorial in the available literature.

12

Gradient Boosting Application in Forecasting of Performance Indicators Values for Measuring the Efficiency of Promotions in FMCG Retail

Henzel Joanna, Sikora Marek

Annals of Computer Science and Information Systems

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2020

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Vol. 21

59--68

EN

In the paper, a problem of forecasting promotion efficiency is raised. The authors propose a new approach, using the gradient boosting method for this task. Six performance indicators are introduced to capture the promotion effect. For each of them, within predefined groups of products, a model was trained. A description of using these models for forecasting and optimising promotion efficiency is provided. Data preparation and hyperparameters tuning processes are also described. The experiments were performed for three groups of products from a large grocery company.

13

Analiza porównawcza wybranych metod synchronizacji ramkowej w gęstych sieciach sensorowych

Sikora Marek, Ludwin Wiesław, Wszołek Jacek

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2019

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nr 6

425--428, CD

PL

W pracy przedstawiono rezultaty oceny porównawczej dwóch wybranych metod synchronizacji ramkowej. Obie metody wykorzystywały operację sumowania symboli pilota sekwencji synchronizacyjnej z ciągiem symboli danych informacyjnych. Analizę porównawczą obu tych metod przeprowadzono za pomocą symulacji komputerowych radiowego systemu gromadzenia danych pomiarowych. W zamodelowanym, w środowisku Matlab, systemie – pracującym na częstotliwości 434 MHz – zastosowano generatory nośnej o stabilności częstotliwości ±20 ppm. A to oznaczało brak idealnej synchronizacji czasów próbkowania sygnałów w nadajniku i odbiorniku analizowanego systemu.

EN

The paper presents results of comparative analysis of two methods of frame detection with superimposed pilot sequence in a presence of a frequency offset. Performance of both frame detection methods were evaluated using simulation. Tests were performed for imperfect synchronization of carrier generators operating on 434 MHz with frequency stability of ± 20 ppm.

14

Monitoring and maintenance of a gantry based on a wireless system for measurement and analysis of the vibration level

Sikora Marek, Szczyrba Krzysztof, Wróbel Łukasz, Michalak Marcin

Eksploatacja i Niezawodność

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2019

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Vol. 21, no. 2

341--350

EN

The paper describes a system for monitoring and diagnosing a gantry. The main goal of the system is to acquire, visualize and monitor vibration levels of the gantry crucial elements. The system is also equipped with a computing and analytical part which enables predictive maintenance related to the vibration level assessment. The system architecture can be used in other applications too, i.e. those which require a wireless network of vibration sensors to carry out diagnostic tasks.

PL

W artykule przedstawiono system monitorowania i diagnostyki suwnicy bramowej. Głównym zadaniem systemu jest akwizycja, wizualizacja i monitorowanie poziomu drgań newralgicznych elementów suwnicy. System wyposażony jest również w część obliczeniowoanalityczną, umożliwiającą realizację zadań predykcyjnego utrzymania ruchu (ang. predictive maintenance) związanych z oceną poziomu drgań. Architektura systemu umożliwia wykorzystanie go również do innych zastosowań, w których dla realizacji zadania diagnostyki wymagana jest bezprzewodowa sieć czujników drgań.