Wyniki wyszukiwania - Biblioteka Nauki

1

A study of digital transformation and MSMEs performance from a spatial perspective: Evidence from China

100%

Zheng B. , Yuan Y. , Li H. , Jiang Y.

Journal of Economics and Management

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2023

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tom 45

319-343

EN

Aim/purpose – Not only have micro, small, and medium enterprises (MSMEs) been regarded as a driving force of the national economy, but they have also become important in promoting innovation and entrepreneurship. In general, today’s MSMEs face problems, such as high business costs, insufficient innovation, and inadequate management capabilities, that have all forced the digital transformation of MSMEs. However, in existing studies, the impact of digital transformation on performance is controversial, and the subjects are generally listed companies. In this paper, we have decided to use micro business survey data and analyze them from a spatial perspective to explore how MSMEs’ digital transformation plays a role in influencing performance and the path of its effect. Design/methodology/approach – We use a sampling method with a dual directory-regional sampling frame to investigate MSMEs in Ningbo City, Zhejiang Province, China and then delve into the impact of digital transformation on enterprise performance from a spatial perspective by the spatial weighted logit model. Findings – Hierarchical analysis shows that there is a large room for improvement in the Digital transformation of enterprises. The digitalization level of an enterprise has a positive impact on performance. While from a spatial perspective, the digitalization level of neighboring enterprises has a negative impact on the performance of the enterprise. Path analysis shows that the digital transformation of enterprises can increase innovation, reduce costs, and improve the performance of enterprises. Originality/value – We provide an empirical basis for vigorously promoting the digital transformation of enterprises, jointly building digital parks, and improving enterprise performance by reducing costs and improving efficiency. At the same time, it provides relevant suggestions for digital transformation for manufacturing MSMEs that are hesitant to see or are at a loss in the digital transformation and helps manufacturing MSMEs to achieve cost reduction and increase efficiency.

2

Performance analysis of intelligent agents in complex event processing systems

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Walkowiak T. , Mazurkiewicz J. , Sugier J. , Śliwiński P.

Safety and Reliability of Systems and Processes

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2022

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tom Summer Safety and Reliability Seminar 2022

195--204

EN

The chapter discusses the performance aspects of intelligent agents in Complex Event Processing (CEP) systems. The contemporary solution for implementing CEP systems is based on available software components (Siddhi) and modern implementation techniques (Kubernetes). However, Siddhi lacks the implementation of modern deep learning algorithms. Hence, the concept of intelligent agent is introduced. A case study with a set of intelligent agents designed to handle real-world events related to environmental data monitoring is presented. The results of the case study discussion indicate a reasonable scale for tuning the Event Processing Element (EPA) topology with correct responses and the required output performance level. These results have important implications for the practical implementation of the EPA structure, i.e., the use of GPUs in CEP systems. Finally, the results of performance analysis of different implementations of intelligent agents are presented and discussed.

3

Queueing systems and networks. Models and applications

100%

Filipowicz B. , Kwiecień J.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2008

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tom Vol. 56, nr 4

379-390

EN

This article describes queueing systems and queueing networks which are successfully used for performance analysis of different systems such as computer, communications, transportation networks and manufacturing. It incorporates classical Markovian systems with exponential service times and a Poisson arrival process, and queueing systems with individual service. Oscillating queueing systems and queueing systems with Cox and Weibull service time distribution as examples of non-Markovian systems are studied. Jackson’s, Kelly’s and BCMP networks are also briefly characterized. The model of Fork-Join systems applied to parallel processing analysis and the FES approximation making possible of Fork-Join analysis is also presented. Various types of blocking representing the systems with limited resources are briefly described. In addition, examples of queueing theory applications are given. The application of closed BCMP networks in the health care area and performance evaluation of the information system is presented. In recent years the application of queueing systems and queueing networks to modelling of human performance arouses researchers’ interest. Hence, in this paper an architecture called the Queueing Network-Model Human Processor is presented.

4

A Performance Analysis of IEEE 802.11ax Networks

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Natkaniec M. , Prasnal Ł. , Szymakowski M.

International Journal of Electronics and Telecommunications

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2020

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tom Vol. 66, No. 1

225--230

EN

The paper is focused on the forthcoming IEEE 802.11ax standard and its influence on Wi-Fi networks performance. The most important features dedicated to improve transmission effectiveness are presented. Furthermore, the simulation results of a new transmission modes are described. The comparison with the legacy IEEE 802.11n/ac standards shows that even partial implementation of a new standard should bring significant throughput improvements.

5

On the Performance of Cellular Networks with Adaptive Modulation and Energy Harvesting : A Stochastic Geometry Approach

100%

Ho N.-M. , Phan T.-T. , Nguyen S. Q. , Tu L.-T.

Annals of Computer Science and Information Systems

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2022

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tom Vol. 33

115--120

EN

The performance of ultra-dense cellular networks considering both adaptive discrete modulation (ADM) and energy harvesting (EH) is investigated. Particularly, mobile users (MUs) are charged its battery from all ambient radio frequency (RF) signals. Based on the amount of harvested energy as well as the channel conditions, MU will actively choose an appropriate modulation scheme that not only maximizes the rate but also satisfies the quality-of-service (QoS). Moreover, we consider the spatial-temporal correlation at the signal-to-interference-plus-noise ratios (SINRs) of base stations (BSs) which are totally different from work in the literature. Several important metrics are investigated such as, occurrence probabilities of different modulation schemes (Poc), coverage probability (Pcov), and achievable spectral efficiency (ASE). Finally, the results highlight the superiority of the proposed scheme compared to the conventional fixed modulation

6

A Performance Analysis of IEEE 802.11ax Networks

100%

Natkaniec M. , Prasnal Ł. , Szymakowski M. , Natkaniec M. , Prasnal Ł. , Szymakowski M.

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7

System dynamics as a decision support system for machine tool selection

100%

Adane T. F. , Nicolescu M.

Journal of Machine Engineering

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2016

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tom Vol. 16, No. 3

102--125

EN

The worldwide competitive economy, the increase in sustainable issue and investment of new production line is demanding companies to choose the right machine from the available ones. An improper selection can negatively affect the overall performance of the manufacturing system like productivity, quality, cost and companys responsive manufacturing capabilities. Thus, selecting the right machine is desirable and substantial for the company to sustain competitive in the market. The ultimate objective of this paper is to formulate a framework for machining strategy and also provide methodology for selecting machine tool from two special purpose machine tools in consideration of interaction of attributes. A decision support system for the selection of machine tool is developed. It evaluates the performance of the machining process and enhances the manufacturer (decision maker) to select the machine with respect to the performance and the pre-chosen criteria. Case study was conducted in a manufacturing company. A system dynamics modelling and simulation techniques is demonstrated towards efficient selection of machine tool that satisfy the future requirement of engine-block production.

8

Perfect Hashing Schemes for Mining Traversal Patterns

100%

Chang C.-C. , Lin C.-Y. , Chou H.

Fundamenta Informaticae

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2006

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tom Vol. 70, nr 3

185-202

EN

Hashing schemes are a common technique to improve the performance in mining not only association rules but also sequential patterns or traversal patters. However, the collision problem in hash schemes may result in severe performance degradation. In this paper, we propose perfect hashing schemes for mining traversal patterns to avoid collisions in the hash table. The main idea is to transform each large itemsets into one large 2-itemset by employing a delicate encoding scheme. Then perfect hash schemes designed only for itemsets of length two, rather than varied lengths, are applied. The experimental results show that our method is more than twice as faster than FS algorithm. The results also show our method is scalable to database sizes. One variant of our perfect hash scheme, called partial hash, is proposed to cope with the enormous memory space required by typical perfect hash functions. We also give a comparison of the performances of different perfect hash variants and investigate their properties.

9

Calculating Home Advantage in the First Decade of the 21th Century UEFA Soccer Leagues

100%

Saavedra García M. , Gutiérrez Aguilar Ó. , Marques P. S. , Torres Tobío G. , Romero J. J. F.

Journal of Human Kinetics

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2013

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tom 38

141-150

EN

Home advantage has been studied in different sports, establishing its existence and its possible causes. This article analyzes the home advantage in soccer leagues of UEFA countries in the first part of the 21st century. The sample of 52 countries monitored during a period of 10 years allows us to study 520 leagues and 111,030 matches of the highest level in each country associated with UEFA. Home advantage exists and is significant in 32 of the 52 UEFA countries, where it equals 55.6%. A decrease can be observed in the tendency towards home advantage between the years 2000 and 2010. Values between 55 and 56 were observed for home advantage in the top ten leagues in Europe. It has also been observed that home advantage depends on the level of the league evaluated using UEFA’s 2010/11 Country coefficients. The home advantage is calculated taking into account the teams’ position and the points obtained in each of the leagues. A direct relationship was observed with the number of points gained and an inverse relationship was observed with the team position.

10

Ball Possession Effectiveness in Men’s Elite Floorball According to Quality of Opposition and Game Period

100%

Gómez M.-Á. , Prieto M. , Pérez J. , Sampaio J.

Journal of Human Kinetics

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2013

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tom 38

227-237

EN

The aim of the present study was to identify the importance of floorball tactical variables to predict ball possession effectiveness, when controlling quality of opposition and game periods. The sample was composed by 1500 ball possessions, corresponding to 14 games randomly selected from the International Championships played during 2008 and 2010 (World Championship, Four nations tournament and classificatory phases for World Championship) by teams from different competition levels (HIGH, INTERMEDIATE and LOW). The effects of the predictor variables on successful ball possessions according to the three game contexts (HIGH vs. HIGH; HIGH vs. LOW; LOW vs. LOW games) were analyzed using Binomial Logistic Regressions. The results showed no interaction with the game period. In HIGH vs. HIGH games, quality of opposition showed an association with ball possession effectiveness with ending zone, offensive system, possession duration, height of shooting and defensive pressures previous to the shot. In HIGH vs. LOW games the important factors were the starting zone, possession duration, defensive pressure previous to the last pass and to the shot, technique of shooting and the number players involved in each ball possession. Finally, in LOW vs. LOW games, the results emphasized the importance of starting and ending zones, the number of passes used and the technique of shooting. In conclusion, elite floorball performance is mainly affected by quality of opposition showing different game patterns in each context that should be considered by coaches when preparing practices and competitions.

11

Multiscale Processing Performance for Motion Capture

100%

Jablonski B. , Kulbacki M.

Machine Graphics and Vision

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2011

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tom Vol. 20, No. 3

251-266

EN

Motion capture systems help record human motion as a sequence of joint angle vectors and analyse it in multiple degrees of freedom with high accuracy. Motion, as many other signals, might contain information which is stored on many different scales. Hence the use of a multiscale model might help correctly distinguish or analyse motion properties. In this paper we analyse the capabilities of a multiscale motion model to help distinguish meaningful motion features, whilst the unnecessary components (like noise) get removed. We performed experiments based on real motion capture data to analyse the discriminative properties of the multiscale approach. The main goal of experiments was to check the clustering performance of a multiscale model. The detailed results are presented and discussed, showing the capabilities and advantages of multiscale model application.

12

Analysis of the efficiency of complex systems

100%

Antkowiak A.

Mathematica Applicanda

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2017

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tom 45

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nr 2

EN

The subject of considerations shall be mathematical models describing the fluctuation of states of complex systems. The purpose of this work is to give a defined system (considering failures, activation process, and a possibility of repair), its description along with the basic indications of multi-level system analysis, and in particular the definition of steady-state probabilities and performance analysis. The modeling tool here are continuous-time Markov chains with finite number of states

13

Performance analysis of an InAs/GaSb superlattice barrier photodetector covering the full LWIR spectral domain

100%

Alchaar R. , Rodriguez J.-B. , Höglund L. , Naureen S. , Costard E. , Christol P.

Opto-Electronics Review

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2020

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tom Vol. 28, No. 3

164--170

EN

In this paper, we present the electrical and electro-optical characterizations of an InAs/GaSb type-2 superlattice barrier photodetector operating in the full longwave infrared spectral domain. The fabricated detectors exhibited a 50% cut-off wavelength around 14 μm at 80 K and a quantum efficiency slightly above 20%. The dark current density was of 4.6×10⁻² A/cm² at 80 K and a minority carrier lateral diffusion was evaluated through dark current measurements on different detector sizes. In addition, detector spectral response, its dark current-voltage characteristics and capacitance-voltage curve accompanied by electric field simulations were analyzed in order to determine the operating bias and the dark current regimes at different biases. Finally, dark current simulations were also performed to estimate a minority carrier lifetime by comparing experimental curves with simulated ones.

14

Match Characteristics and Rally Pace of Male Tennis Matches in Three Grand Slam Tournaments

88%

Carboch J. , Siman J. , Sklenarik M. , Blau M.

Physical Activity Review

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2019

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nr 7

49-56

EN

A tennis player has a very limited time to hit an incoming ball; however, the ball delivery time is affected by playing on different surfaces. Consequently, the playing surface can affect also other match characteristics as players can reach more incoming balls or can move on the court with different intensity (cover more distance). Aim of Study: The aim is to analyze the rally pace characteristics and the frequency of rally shots in men's matches in the Australian Open, French Open and Wimbledon in 2017. Material and Methods: We analyzed 24 male matches in the Australian Open, French Open and Wimbledon in 2017. Analysis of variance including post-hoc tests and Cohen d were used to compare the point duration, number of rally shots, time between the points, rally pace and work to rest ratio among these tournaments. Results: The rally pace (mean ball flight time between the opponents) was the fastest in the Australian Open (1.22 s) and was significantly faster (p=0.003) compared to the French Open (1.35 s). The rally pace in the Wimbledon reached 1.27 s and Cohen d showed large effect between the rally pace in the Wimbledon and French Open or moderate effect between the Australian Open and Wimbledon. There were other differences among the tournaments, but the lowest number of rally shots (4.07), point duration (5.30 s) and time between points (18.82 s) was reached in the Wimbledon. More than 50 % of all points were finished within the first four shots (most in the Wimbledon - 66%). Conclusion: These findings show and endorse the impact of surface differences on the game performance in professional tennis and can be used to shape specific training sessions on different surfaces.

15

Evaluation of Performance and Efficiency of Polish Open-End Mutual Funds under High Volatility Environment in Financial Markets

88%

Lisak F.

Annales Universitatis Mariae Curie-Skłodowska, sectio H – Oeconomia

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2022

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tom 56

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nr 4

63-82

EN

Theoretical background: Retail investors in the financial market have nowadays access to a wide range of investment products. One of the types of such products are open-end investment funds, which by design are asset masses managed by professional entities. Open-end investment funds became one of the more popular financial instruments that retail customers purchase. Purpose of the article: This article aims at determining the efficiency of mutual funds as measured by the rate of return. An important point of the study is to determine whether funds with lower total risk as measured by standard deviation achieved lower losses. Research methods: The research method is an analysis of performance of twenty Polish open-ended mutual funds in three different time horizons, by using classic mutual fund performance measures adjusted for negative returns, i.e. Sharpe, Treynor and Jensen alpha indicators as well as the Israelsen and Treynor ratios adjusted for negative return. Main findings: It has been observed that the high volatility in the financial market had a direct negative impact on the returns of these funds. When comparing the Treynor ratio adjusted for negative returns values it appears that some of the analysed equity funds performed better than, for example, stable growth funds. In case of high volatility in the stock market, both in the long and short term, the analysed stable growth funds did not bring more value to investors in relation to the total risk incurred than balanced or even equity funds, which is particularly noticeable in the case of three-year and annual results. This is because asset diversification did not fully work in the high market volatility seen since the beginning of 2022 mostly due to falling prices of debt securities caused by interest rate increases. The article also contributes to the interpretation of Sharpe and Israelsen ratios in case of similar negative rates of return and different volatility measured, because the Israelsen ratio may not be the best to compare such funds as it prioritizes the funds with lower risk and does not consider relation of risk to return.

16

The analysis of shaft sinking progress as a function of technical and organizational parameters

88%

Bołoz Ł.

Multidisciplinary Aspects of Production Engineering

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2019

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tom Vol. 2, Iss. 1

203--212

EN

In underground mines, where the deposit is located at considerable depths, mining shafts are key excavations. The project of making the deposit available requires selection of appropriate shaft sinking technology adapted to geological and hydrological conditions and natural hazards. Shafts can be made using the classic drilling and blasting technique or mechanical cutting of the shaft face. Mechanical cutting requires the use of a mining machine, which together with machines for loading and hauling the output and protecting the side walls is a shaft complex. Drilling using mechanized shaft complexes allows for high efficiency and work safety. To improve the efficiency of drilling, it is particularly important to implement many processes in parallel. The article presents an analysis of the progress of shaft sinking with a mechanized complex as a function of technical and organizational parameters. The analysis concerned a new generation cutting shaft complex, developed for the needs of shaft sinking for one of the Polish hard coal mines. The calculations were carried out for a shaft with a maximum diameter of 9.5 m and a total depth of 830 m. The article briefly presents a new solution for the shaft complex. There are presented results of calculations of daily drilling progress and total time of shaft sinking for the developed working technology of this complex. The efficiency of the complex depends on many factors related to technical parameters of individual machines and devices forming the complex and organizational parameters, hence a multi-variant analysis was carried out.

17

Performance and overhead analysis in runtime code modiﬁcation

88%

Rudy J.

Journal of Applied Computer Science

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2013

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tom Vol. 21, nr 2

117--136

EN

Availability is a key issue for a wide array of software systems and its importance in the era of cloud computing only continues to grow.For such systems every software update or system fault means decrease in availability or loss of the system’s state and both may involve heavy cost. In order to solve these problems, the system needs to either be able to quickly recover and retrieve its previous state or have the possiblity of applying the needed changes at runtime, without the need to shut the system down. This paper proposes an experimental Versatile Code Generator tool, originally intended for simulating software, prototyping and programmable computer games,as a possible solution to aboveproblems.The tool is capable of creating Cprograms subject to runtime code modiﬁcation. The main focus of this paper are performance tests, researching overhead generated by the tool. To this end, static (i.e. original) and dynamic (i.e. created by the tool) applications were compared in a number of performance factors (including compilation and execution time, memory usage, source and executable code size).Diﬀerent cases, including various functions number and size, various number and types of function arguments, have been considered.

18

Effect of Three Technical Arms Swings on The Elevation of the Center of Mass During a Standing Back Somersault

88%

Mkaouer B. , Jemni M. , Amara S. , Chaabène H. , Padulo J. , Tabka Z.

Journal of Human Kinetics

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2014

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tom 40

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nr 1

37-48

EN

Arms swing during standing back somersaults relates to three different “gymnastics schools”, each is considered “optimal” by its adepts. In the three cases, technical performance, elevation and safety differ. Therefore, the aim of this study was to compare the mechanical variables of three different arms swing techniques in the performance of a standing back tucked somersault. Five high-level male gymnasts (age: 23.17±1.61 yrs; body height: 1.65±0.05 m; body mass: 56.80±7.66 kg) randomly performed standing somersaults under three conditions, each following a different arms’ swing technical angle (270°, 180° and 90°). A force plate synchronized with a three dimensional movement analysis system was used to collect kinetic and kinematic data. Significant differences were observed between somersaults’ performance. The back somersault performed with 270° arms swing showed the best vertical displacement (up to 13.73%), while the back somersaults performed with 180° arms swing showed a decrease in power (up to 22.20%). The back somersault with 90° arms swing showed the highest force (up to 19.46%). Considering that the higher elevation of the centre of mass during the flight phase would allow best performance and lower the risk of falls, this study demonstrated that optimal arms’ swing technique prior to back tucked somersault was 270°.

19

Investigation on a quasi-zero-stiffness vibration isolator under random excitation

88%

Wang Y. , Li S. , Cheng C.

Journal of Theoretical and Applied Mechanics

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2016

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tom Vol. 54 nr 2

621--632

EN

The dynamic response and isolation performance of a Quasi-Zero-Stiffness (QZS) vibration isolator using inclined springs as negative stiffness correctors under random excitation are presented in this paper. The probabilistic linearization method is employed to determine the dynamic response of the QZS vibration isolator and compared with the exact solution based on the Fokker-Planck-Kolmogorov (FPK) equation and the equivalent linearization method. Two performance indexes (Mean Square Relative Displacement (MSRD) and Mean Square Acceleration (MSA)) are considered to evaluate the isolation performance of the QZS vibration isolator under random excitation and compared with the equivalent linear vibration isolator. The results show that the MSRD of the QZS vibration isolator is always lower than the equivalent linear vibration isolator, while the MSA of the QZS vibration isolator can be larger or lower than the equivalent linear vibration isolator based on the values of damping ratio and spectral density of the random excitation

20

Modulo N Backoff Scheme for Effective QoS Differentiation and Increased Bandwidth Utilization in IEEE 802.11 Networks

88%

Janczar T. , Konorski J. , Wodniak J. , Pawlikowski K.

Journal of Telecommunications and Information Technology

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2009

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tom nr 2

41-47

EN

The paper presents a new modulo N channel access scheme for wireless local area networks (WLANs). The novel solution derives from the distributed coordination function (DCF) of the IEEE 802.11 standard, further elaborated as enhanced distribution channel access (EDCA) by the 802.11e draft specification. The main innovation concerns improvement of the binary exponential backoff scheme used for collision avoidance in 802.11 networks. The most appealing feature of the new modulo N backoff scheme is that it outperforms the original 802.11 solution in terms of channel utilization ratio under any traffic conditions. Furthermore, the modulo N proposal can be naturally augmented with QoS differentiation mechanisms like 802.11e extensions. The prioritized modulo N scheme achieves better throughput-delay characteristics for multimedia traffic when compared with the original 802.11e proposal. At the same time, the new solution retains backward compatibility and includes all features which have made IEEE 802.11 networks extremely popular nowadays.