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Wyświetlanie 1-15 z 16
Tytuł:
Investigation of the Vibroacoustic Climate inside the Buses Solaris Urbino 18 Used in Public Transport Systems - Drivers Cab
Autorzy:
Damijan, Z.
Skrzyniarz, S.
Kwaśniewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1504428.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.40.-a
46.40.-f
07.10.-h
46.40.Cd
Opis:
Despite new technological solutions and attempts to improve the working conditions during driving of vehicles, city bus drivers are still exposed to negative impacts of noise and vibrations, causing stress, increased fatigue and leads to numerous diseases. Therefore it seems merited to investigate the acoustic climate and the working conditions during the operation of Solaris Urbino 18 vehicles, widely used in public transport systems. The main purpose of this research program was to show the impacts that the conditions at work might have on bus drivers or to demonstrate that these impacts do not exist. No extensive major research was done to investigate the influence of the conditions at work on functional stability of bus drivers. Investigation of vehicle vibroacoustic climate in working (normal) environment are led rarely. Measurements often are done in idle run or during ride at manoeuvring site only for 2-3 min. In this paper results of acceleration and noise in idle run are presented for 3 min measurement and for 3 h until ride. All measurements are done in working environment on streets of Tychy city with passengers on board. In this paper detailed numerical analysis of vibroacoustic parameters are presented. Physical parameters like noise spectral analysis in 1/3 octave frequency bands and histogram of acoustic pressure level in the driver's cabin are presented in results.
Źródło:
Acta Physica Polonica A; 2011, 119, 6A; 1068-1072
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the Vibroacoustic Climate Inside the Buses MAN SG242 Used in Public Transport Systems
Autorzy:
Damijan, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1537389.pdf
Data publikacji:
2010-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.40.-a
07.10.-h
43.40.Lc
07.64.+z
Opis:
A driver of a municipal transport bus is more liable to vibration-acoustic stimuli connected with the movement of the vehicle than a passenger. In literature on the subject noise and vibration exposures are categorised into passive (whereby passengers are exposed) and active (driver's or machine operator's exposure). Despite new technological solutions and attempts to improve the working conditions during the operation of vehicles, city bus drivers are still exposed to negative impacts of noise and vibrations, causing stress, increased fatigue and lead to numerous diseases. It is required, therefore, that the working conditions for drivers should be monitored on a regular basis. In order that they work safely, their working conditions should be as comfortable as possible, in terms of physical and psychical conditions and free from any nuisance. Therefore it seems merited to investigate the acoustic climate (i.e. acoustic phenomena caused by the sources of noise of vibrations in the function of time and space) and the working conditions during the operation of MAN SG242 vehicles, widely used in public transport systems. The following conclusions can be formulated (based on the conducted tests): the highest effective weighted values of vibration acceleration a_w, eq (0.823 m/$s^{2}$) (exceedance of the legitimate value) were noted in the passengers' compartment in the middles of the vehicle, the lowest- in the driver's cabin (0.411 m/$s^{2}$). In the driver's cabin, the peak noise level $L_C$ peak = 138.7 dB was exceeded; as the 1/3 octave analyses show, in the driver's cabin dominates low-frequency noise with the frequency from 10 to 25 Hz and the acoustic pressure level of about 90 dB (G). The research has been conducted within the framework of the author's research no 10.10.130.140 and the statuary ones no 11.11.130.119.
Źródło:
Acta Physica Polonica A; 2010, 118, 1; 27-30
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the Vibroacoustic Climate Inside the Buses Solaris Urbino 12 Used in Public Transport Systems
Autorzy:
Damijan, Z.
Iwański, D.
Dahlke, G.
Powiązania:
https://bibliotekanauki.pl/articles/1490375.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.40.-a
07.10.-h
43.40.Lc
07.64.+z
Opis:
Despite new technological solutions and attempts to improve the working conditions during the operation of vehicles, city bus drivers are still exposed to negative impacts of noise and vibrations, causing stress, increased fatigue and lead to numerous diseases. Therefore it seems merited to investigate the acoustic climate (i.e. acoustic phenomena caused by the sources of noise of vibrations in the function of time and space) and the working conditions during the operation of Solaris Urbino 12 vehicles, widely used in public transport systems. The main aim of the research was to show the influence of the 5 day, 8 h working week on selected psycho-physiological parameters on a driver's organism. It was assumed that the main aggravating factor of the driver's organism are vibroacoustics conditions of a work place. The results of this research will be presented in due course. This work presents the research on vibroacoustic climate in one of many city buses used - Solaris Urbino 12. Investigation of the vibroacoustic climate is the branch of environmental biophysics. The measurements, tests and analysis are genuine because they were carried out under real conditions, with passengers, in the long stretches of time and in the entire route of the vehicle. Presented results are very rarely reported in the literature.
Źródło:
Acta Physica Polonica A; 2012, 121, 1A; A-032-A-037
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of the Vibroacoustic Environment Conditions on Functional Stability of Drivers
Autorzy:
Damijan, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1537357.pdf
Data publikacji:
2010-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.40.-a
43.80.-n
43.80.-p
87.50.Y-
Opis:
Despite new technological solutions and attempts to improve the working conditions during the operation of vehicles, city bus drivers are still exposed to negative impacts of noise and vibrations. This research project was undertaken in response to the lack of holistic analyses of the environmental factors that might impact on the city bus drivers at work. No extensive major research was done to investigate the influence of the conditions at work on functional stability of bus drivers and basic physiological parameters of the human body (systolic and diastolic pressure, pulse rate, temperature in the ear channel, loading of postural muscles, blood circulation determined with the use of a thermovision camera, fatty tissue content, body mass and physical condition (squeezing and pressing exercises). the main purpose of this research program was to show the impacts that the conditions at work might have on bus drivers or to demonstrate that these impacts do no exist.
Źródło:
Acta Physica Polonica A; 2010, 118, 1; 23-26
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of General Low Frequency Vibration on Posture Stability
Autorzy:
Damijan, Z.
Uhryński, A.
Powiązania:
https://bibliotekanauki.pl/articles/1490372.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.40.-a
07.10.-h
46.32.+x
87.50.Y-
Opis:
The work presents the research and analysis concerning general low frequency vibration and its influence on posture stability. The research was conducted in two phases: a group exposed to vibration - August 2006, a control group: November 2006 in Krynica-Zdrój. An exposed group (29 participants/took part in 19 training sessions, each lasting 20 min, of low frequency vibration, standing position) applied to each participant at fixed time of the day. The low frequency vibration amplitude was 4 mm, while the frequency was 3.5 Hz. Before and after the session the posturographic examination of posture stability was conducted. The control group (33 participants) also took part in 19 everyday 20 min sessions with no vibrations and only measurements conducted. The results were analyzed concerning statistics using Statistica. For the sake of the analysis the significance level was p = 0.05, the parametric t-test and the nonparametric Kolmogorov-Smirnov tests were used for two groups of independent variables. Having conducted the research and analysis, one can state that 20 min exposure to low frequency vibration results in significant changes in posture stability and 19 day long vibration training changes significantly the posture stability among the participants. The observed changes were of positive nature. The work introduces research on the possibility of using low-frequency vibration to improve human stability. The results presented concern biophysics in rehabilitation of posture stability and are not often met in specialist literature.
Źródło:
Acta Physica Polonica A; 2012, 121, 1A; A-028-A-031
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Models of Pedestrian Evacuation based on Cellular Automata
Autorzy:
Mrowinski, M.
Gradowski, T.
Kosinski, R.
Powiązania:
https://bibliotekanauki.pl/articles/1409052.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.40.-a
45.70.Vn
05.50.+q
05.70.Fh
Opis:
We study two models of pedestrian evacuation based on cellular automata and intelligent agents. We use the static floor field approach and augment it with additional transition rules (random movement and preservation of personal space) in order to model various aspects of human behaviour. Through numerical simulations we investigate pedestrian evacuation from rooms with various geometries (e.g. empty room, classroom). Using heatmaps (density diagrams of pedestrians), average evacuation times, velocity and other parameters we study the effectiveness of evacuation and potential dangers pedestrians may encounter.
Źródło:
Acta Physica Polonica A; 2012, 121, 2B; B-95-B-100
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of Vibroacoustic Climate on Driver's Postural Stability for Eyes Closed in Driver's Cabin
Autorzy:
Damijan, Z.
Skrzyniarz, S.
Kwaśniewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1504430.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.40.-a
07.10.-h
46.32.+x
87.50.Y-
Opis:
Several levels of the nervous system are responsible for stability of the vertical position in humans. Three basic inputs are involved: atrial, visual and proprioceptive as well as mechanoreceptors present in the skin. Signals from these inputs control the body posture and its orientation with respect to internal and external reference systems. External systems are formed based on the gravitation field and visual stimuli. Internal systems are generated in the central nervous system by polymodal representations, also referred to as body schema. Some of environmental factors of driver's work place could disturb postural stability. Almost all vehicles are according with actual norms and directives. We investigate how normal week of work has impact on postural stability in new city buses. We concentrate on postural stability for closed eyes. In this paper results of investigation were presented.
Źródło:
Acta Physica Polonica A; 2011, 119, 6A; 1073-1076
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Drivers Working Environment οn Thermical Changes of Their Organism
Autorzy:
Damijan, Z.
Uhryński, A.
Powiązania:
https://bibliotekanauki.pl/articles/1537402.pdf
Data publikacji:
2010-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
08.89.40.-a
46.40.-f
87.19.R-
43.80.-n
43.80.+p
Opis:
The work presents the research on the influence of driver's working environment on thermical changes in their organism. The experiment was conducted between 24 and 31 March 2008 in the tram depot of Public Transport Agency in Tychy. Thermo-visual photos were conducted twice a day - before starting work and after finishing it during six following days. The group consisted of 14 drivers aged 24-49 driving city buses (the make: Solaris Urbino 18). The results were analyzed concerning statistics using Statistica. For the sake of the analysis the significance level was p = 0.05, the non-parametric Wilcoxon test or parametric T-test were used for two groups of dependent variables. The research and analysis show that driver's working environment has valid influence on thermical changes in their organism.
Źródło:
Acta Physica Polonica A; 2010, 118, 1; 35-40
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evacuation in the Social Force Model is not Stationary
Autorzy:
Gawroński, P.
Kułakowski, K.
Kämpf, M.
Kantelhardt, J.
Powiązania:
https://bibliotekanauki.pl/articles/1409031.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.75.Fb
05.40.-a
05.45.Tp
89.40.Bb
Opis:
An evacuation process is simulated within the Social Force Model. Thousand pedestrians are leaving a room by one exit. We investigate the stationarity of the distribution of time lags between instants when two successive pedestrians cross the exit. The exponential tail of the distribution is shown to gradually vanish. Taking fluctuations apart, the time lags decrease in time till there are only about 50 pedestrians in the room, then they start to increase. This suggests that at the last stage the flow is laminar. In the first stage, clogging events slow the evacuation down. As they are more likely for larger crowds, the flow is not stationary. The data are investigated with detrended fluctuation analysis and return interval statistics, and no pattern transition is found between the stages of the process.
Źródło:
Acta Physica Polonica A; 2012, 121, 2B; B-77-B-81
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Statistical Collapse of Excessive Market Losses
Autorzy:
Denys, M.
Jagielski, M.
Gubiec, T.
Kutner, R.
Stanley, H.
Powiązania:
https://bibliotekanauki.pl/articles/1398834.pdf
Data publikacji:
2016-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.65 Gh
05.40.-a
89.75.Da
Opis:
We analytically derive superstatistics (or complex statistics) that accurately model empirical market activity data (supplied by Bogachev, Ludescher, Tsallis, and Bunde) exhibiting transition thresholds. We measure the interevent times between excessive losses (that is, greater than some threshold) and use the mean interevent time as a control variable to derive a universal description of empirical data collapse. Our superstatistic value is a power-law corrected by the lower incomplete gamma function, which asymptotically tends toward robustness but initially gives an exponential. We find that the scaling shape exponent that drives our superstatistics subordinates themselves and a "superscaling" configuration emerges.
Źródło:
Acta Physica Polonica A; 2016, 129, 5; 913-916
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hierarchical Cont-Bouchaud Model
Autorzy:
Paluch, R.
Suchecki, K.
Hołyst, J.
Powiązania:
https://bibliotekanauki.pl/articles/1388158.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.65.-s
89.65.Gh
89.75.-k
05.40.-a
Opis:
We extend the well-known Cont-Bouchaud model to include a hierarchical topology of agent's interactions. The influence of hierarchy on system dynamics is investigated by two models. The first one is based on a multi-level, nested Erdős-Rényi random graph and individual decisions by agents according to Potts dynamics. This approach does not lead to a broad return distribution outside a parameter regime close to the original Cont-Bouchaud model. In the second model we introduce a limited hierarchical Erdős-Rényi graph, where merging of clusters at a level h+1 involves only clusters that have merged at the previous level h and we use the original Cont-Bouchaud agent dynamics on resulting clusters. The second model leads to a heavy-tail distribution of cluster sizes and relative price changes in a wide range of connection densities, not only close to the percolation threshold.
Źródło:
Acta Physica Polonica A; 2015, 127, 3A; A-108-A-112
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Zipf Strategy for Short-Term Investments in WIG20 Futures
Autorzy:
Bieda, B.
Chodorowski, P.
Grech, D.
Powiązania:
https://bibliotekanauki.pl/articles/1409028.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.45.Tp
89.75.Da
05.40.-a
89.65.Gh
Opis:
We apply the Zipf power law to financial time series of WIG20 index daily changes (open-close values). Thanks to the mapping of time series signal into the sequence of 2k+1 'spin-like' states, where k=0, 1/2, 1, 3/2, ..., we are able to describe any time series increments, with almost arbitrary accuracy, as the one of such 'spin-like' states. This procedure leads in the simplest non-trivial case (k = 1/2) to the binary data projection. More sophisticated projections are also possible and mentioned in the article. The introduced formalism allows then to use Zipf power law to describe the intrinsic structure of time series. The fast algorithm for this implementation was constructed by us within $\text{Matlab}^{TM}$ software. The method, called Zipf strategy, is then applied in the simplest case k = 1/2 to WIG 20 open and close daily data to make short-term predictions for forthcoming index changes. The results of forecast effectiveness are presented with respect to different time window sizes and partition divisions (word lengths in Zipf language). Finally, the various investment strategies improving return of investment (ROI) for WIG20 futures are proposed. We show that the Zipf strategy is the appropriate and very effective tool to make short-term predictions and therefore, to evaluate short-term investments on the basis of historical stock index data. Our findings support also the existence of long memory in financial data, exceeding the known in the literature 3 days span limit.
Źródło:
Acta Physica Polonica A; 2012, 121, 2B; B-7-B-10
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multifractal Background Noise of Monofractal Signals
Autorzy:
Grech, D.
Pamuła, G.
Powiązania:
https://bibliotekanauki.pl/articles/1408977.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.45.Tp
89.75.Da
05.40.-a
89.75.-k
89.65.Gh
Opis:
We investigate the presence of multifractal residual background effect for monofractal signals which appears due to the finite length of the signals and (or) due to the constant long memory the signals reveal. This phenomenon is investigated numerically within the multifractal detrended fluctuation analysis (MF-DFA) for artificially generated time series. Next, the analytical formulas enabling to describe the multifractal content in such signals are provided. Final results are shown in the frequently used generalized Hurst exponent h(q) multifractal scenario as a function of time series length L and the autocorrelation scaling exponent value γ. The obtained results may be significant in any practical application of multifractality, including financial data analysis, because the "true" multifractal effect should be clearly separated from the so called "multifractal noise" resulting from the finite data length. Examples from finance in this context are given. The provided formulas may help to decide whether one deals with the signal of real multifractal origin or not and make further step in analysis of the so called spurious or corrupted multifractality discussed in literature.
Źródło:
Acta Physica Polonica A; 2012, 121, 2B; B-34-B-39
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multifractality of Nonlinear Transformations with Application in Finances
Autorzy:
Grech, D.
Pamuła, G.
Powiązania:
https://bibliotekanauki.pl/articles/1400170.pdf
Data publikacji:
2013-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.45.Df
05.45.Tp
89.65.Gh
89.75.Da
89.75.-k
89.20.-a
05.40.-a
Opis:
We study the multifractal effects of nonlinear transformations of monofractal, stationary time series and apply the found results to measure the "true" unbiased multifractality generated only by multiscaling properties of initial (primary) data before transformations. A difference is stressed between "naive" observed multifractal effects calculated directly within detrended multifractal analysis as the spread Δh of the generalized Hurst exponents h(q) and the more reliable unbiased multifractality received after subtraction of residual bias effects generated by nonlinear transformations of initial data and coupled with finite size effects in time series. This property is investigated for volatile series of the real main world financial indices. A difference between multifractal properties of intraday and interday quotes is also pointed out in this context for the Warsaw Stock Exchange WIG index. Finally, based on the observed feature of real nonstationary data, a new measure of unbiased multifractality in signals is introduced. This measure comes from an analysis of the whole generalized Hurst exponent profile instead of looking just at its edge behavior $h^{±} ≡ h(q→ ±∞)$. Such an approach seems to be particularly useful when h(q) is not a monotonic function of the moment order q. Interesting examples with extreme events from finance are presented. They convince that an analysis directed only on investigation of the edges $h^{±}$ in multifractal spectrum may be misleading.
Źródło:
Acta Physica Polonica A; 2013, 123, 3; 529-537
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interplay between endogenous and exogenous fluctuations in financial markets
Autorzy:
Gontis, V.
Powiązania:
https://bibliotekanauki.pl/articles/1075435.pdf
Data publikacji:
2016-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.65.Gh
89.75.Da
05.10.Gg
05.40.-a
05.45.Tp
Opis:
We address microscopic, agent based, and macroscopic, stochastic, modeling of the financial markets combining it with the exogenous noise. The interplay between the endogenous dynamics of agents and the exogenous noise is the primary mechanism responsible for the observed long-range dependence and statistical properties of high volatility return intervals. By exogenous noise we mean information flow or/and order flow fluctuations. Numerical results based on the proposed model reveal that the exogenous fluctuations have to be considered as indispensable part of comprehensive modeling of the financial markets.
Źródło:
Acta Physica Polonica A; 2016, 129, 5; 1023-1031
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 16

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