Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "wydajnosc" wg kryterium: Temat

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 73
Tytuł:
Dynamic performance and stability analysis of an active inerter-based suspension with time-delayed acceleration feedback control
Autorzy:
Wang, Yong
Jin, Xian-Yu
Zhang, Yun-Shun
Ding, Hu
Chen, Li-Qun
Powiązania:
https://bibliotekanauki.pl/articles/2173651.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
active inerter-based suspension
acceleration feedback control
dynamic performance
stability analysis
time delay
kontrola sprzężenia zwrotnego przyspieszenia
wydajność dynamiczna
aktywne zawieszenie na bazie inertera
analiza stabilności
opóźnienie
Opis:
An active inerter-based suspension with acceleration feedback control is proposed in this paper, the time delay generated in the controllers and actuators is considered, which constitutes the time-delayed active inerter-based (TDA-IB) suspension. The dynamic equation of the TDA-IB suspension is established and is a neutral type of delay differential equation (NDDE) in which the time delay exists in the highestorder derivative. The stability analysis is conducted by calculating the number of unstable characteristic roots based on the definite integral stability method, the stable and unstable regions are determined. The effect of time delay and feedback gain on the dynamic performance of the TDA-IB suspension under harmonic, random, and shock excitations is studied in detail and compared with the parallel-connected inerterbased (PC-IB) and traditional suspensions. The results show that the TDA-IB suspension is asymptotically stable for smaller feedback gain and time delay, through increasing the feedback gain, the stable regions shrink, and a smaller time delay could cause the system to become unstable. Furthermore, the time delay could regulate the resonance peak around the unsprung mass natural frequency and generate multiple high-frequency resonance peaks. If the time delay is chosen appropriately and falls into the stable range, the TDA-IB suspension could improve the dynamic performance for the suspension stroke and dynamic tire load while having a deterioration for the vehicle body acceleration compared with the PC-IB and traditional suspensions.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 2; art. no. e140687
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interception of a hypersonic vehicle by low-speed interceptors: novel perspectives and cost optimisation
Autorzy:
Liu, Shuangxi
Liu, Shijun
Yan, Binbin
Zhang, Tong
Zhang, Xu
Yan, Jie
Powiązania:
https://bibliotekanauki.pl/articles/2173726.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
small speed ratio
hypersonic vehicle
interception performance
boundary conditions
współczynnik prędkości mały
pojazd hipersoniczny
wydajność przechwytywania
warunki brzegowe
Opis:
The conditions for accurately intercepting hypersonic vehicles by low-speed interceptors in the terminal guidance process are examined, considering the general form of a guidance scheme. First, based on the concept of the engagement geometry, three interception scenarios are established considering different manoeuvring configurations of the interceptors and hypersonic vehicle. Second, the boundary conditions for intercepting hypersonic vehicles (with speeds higher than those of the interceptors) are specified for the three scenarios, considering several factors: the speed, path angle, line-of-sight angle, and available overload of the interceptor; path angle and manoeuvrability of the hypersonic vehicle; and relative distance between the interceptor and vehicle. A series of simulations are performed to clarify the influence of each factor on the interception performance in the three interception scenarios. The challenges associated with accurately intercepting hypersonic vehicles by low-speed interceptors are summarised, and several recommendations for designing guidance laws are presented.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 6; art. no. e143537
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lyapunov stability based sliding mode observer for sensorless control of permanent magnet synchronous motor
Autorzy:
Navaneethan, Soundirarajan
Kanthalakshmi, Srinivasan
Aandrew Baggio, S.
Powiązania:
https://bibliotekanauki.pl/articles/2173640.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electric vehicles
permanent magnet synchronous motor
sensorless control
sliding mode observer
Lyapunov stability
tracking efficiency
pojazdy elektryczne
silnik synchroniczny z magnesami trwałymi
sterowanie bezczujnikowe
obserwator o ślizgowym trybie pracy
stabilność Lapunova
wydajność śledzenia
Opis:
In recent years there has been an increasing demand for electric vehicles due to their attractive features including low pollution and increase in efficiency. Electric vehicles use electric motors as primary motion elements and permanent magnet machines found a proven record of use in electric vehicles. Permanent magnet synchronous motor (PMSM) as electric propulsion in electric vehicles supersedes the performance compared to other motor types. However, in order to eliminate the cumbersome mechanical sensors used for feedback, sensorless control of motors has been proposed. This paper proposes the design of sliding mode observer (SMO) based on Lyapunov stability for sensorless control of PMSM. The designed observer is modeled with a simulated PMSM model to evaluate the tracking efficiency of the observer. Further, the SMO is coded using MATLAB/Xilinx block models to investigate the performance at real-time.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 2; art. no. e140353
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Possibilities of increasing production efficiency by implementing elements of augmented reality
Autorzy:
Trojanowska, Justyna
Kaščak, Jakub
Husár, Jozef
Knapčíková, Lucia
Powiązania:
https://bibliotekanauki.pl/articles/2173703.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
production efficiency
production equipment
augmented reality
Industry 4.0
maintenance
wydajność produkcji
sprzęt produkcyjny
rozszerzona rzeczywistość
Przemysł 4.0
utrzymanie
Opis:
The publication reflects the current situation concerning the possibilities of using augmented reality (AR) technology in the field of production technologies with the main intention of creating a tool to increase production efficiency. It is a set of individual steps that respond in a targeted manner to the possible need for assisted service intervention on a specific device. The publication chronologically describes the procedure required for the preparation and processing of a CAD model. For this preparatory process, the PTC software package is used which meets the requirements for each of the individual operations. The first step is the routine preparation of CAD models and assemblies. These are prepared based on real models located on the device, and their shape and dimensions correlate with the dimensions of the model on the device. The second phase is the creation and timing of the disassembly sequence. This will provide the model with complete vector data, which is then paired with the CAD models in AR. This phase is one of the most important. It determines the location of the model concerning its relative position on the device, provides information on the relocation of parts of the model after the sequence is started, and essentially serves as a template for the interactive part of the sequence. The last two phases are used to connect CAD models with vector data, determine their position for the position mark, and prepare the user interface displayed on the output device. The result of this procedure is a functional disassembly sequence, used for assisted service intervention of a worker in the spindle drive of the Emco Mill 55 device.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 6; art. no. e143831
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal performance analysis of manned airships in a thermally variable environment
Autorzy:
Shi, Hong
Liu, Meinan
Chen, Jiamin
Zou, Yitao
Powiązania:
https://bibliotekanauki.pl/articles/2173708.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
manned airship
thermal performance
nacelle
temperature difference
flight position
sterowiec załogowy
wydajność cieplna
gondola
różnica temperatur
pozycja lotu
Opis:
The safety and reliability of the manned airship depend to a considerable extent on its thermal performance. In this paper, heat balance equations are developed and solved in the C++ programming language. The temperature variation of the enclosure, gasbag, and nacelles of the manned airship is investigated. In addition, the effects of season, latitude, and orientation on the thermal performance of the manned airship and the airship nacelle are investigated. The results show that: (1) The average temperature difference of the nacelle surface at the same time is 25 K, while the maximum temperature difference in the nacelle is 29 K during the day, (2) the temperature distribution in the nacelle is similar in spring and autumn, with maximum temperature between 306 K and 309 K. The maximum temperature in the nacelle is between 300 K and 303 K in winter while the maximum temperature in the nacelles is between 309 K and 315 K in summer, (3) as the flight position of the manned airship changes from 20°N to 60°N, the average nacelle temperature varies slightly by about 1 K. However, as the latitude increases, the high- temperature region shifts from the bottom of the nacelle to the side of the nacelle, and (4) the temperature distribution of the upper envelope of the airship varies considerably with orientation. However, the average temperature of the nacelle is less impacted by orientation. These results are useful for understanding the thermal performance of manned airships.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 5; art. no. e143105
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorption chiller in a combined heating and cooling system: simulation and optimization by neural networks
Autorzy:
Krzywanski, Jarosław
Sztekler, Karol
Bugaj, Marcin
Kalawa, Wojciech
Grabowska, Karolina
Chaja, Patryk Robert
Sosnowski, Marcin
Nowak, Wojciech
Mika, Łukasz
Bykuć, Sebastian
Powiązania:
https://bibliotekanauki.pl/articles/2128167.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
adsorption heat pump
polygeneration
cooling capacity
low grade thermal energy
artificial neural networks
soft computing
absorpcyjna pompa ciepła
poligeneracja
wydajność chłodnicza
energia cieplna niskiej jakości
sztuczne sieci neuronowe
przetwarzanie miękkie
Opis:
Adsorption cooling and desalination technologies have recently received more attention. Adsorption chillers, using eco-friendly refrigerants, provide promising abilities for low-grade waste heat recovery and utilization, especially renewable and waste heat of the near ambient temperature. However, due to the low coefficient of performance (COP) and cooling capacity (CC) of the chillers, they have not been widely commercialized. Although operating in combined heating and cooling (HC) systems, adsorption chillers allow more efficient conversion and management of low-grade sources of thermal energy, their operation is still not sufficiently recognized, and the improvement of their performance is still a challenging task. The paper introduces an artificial intelligence (AI) approach for the optimization study of a two-bed adsorption chiller operating in an existing combined HC system, driven by low-temperature heat from cogeneration. Artificial neural networks are employed to develop a model that allows estimating the behavior of the chiller. Two crucial energy efficiency and performance indicators of the adsorption chiller, i.e., CC and the COP, are examined during the study for different operating sceneries and a wide range of operating conditions. Thus this work provides useful guidance for the operating conditions of the adsorption chiller integrated into the HC system. For the considered range of input parameters, the highest CC and COP are equal to 12.7 and 0.65 kW, respectively. The developed model, based on the neurocomputing approach, constitutes an easy-to-use and powerful optimization tool for the adsorption chiller operating in the complex HC system.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 3; e137054, 1--11
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorption chiller in a combined heating and cooling system: simulation and optimization by neural networks
Autorzy:
Krzywanski, Jarosław
Sztekler, Karol
Bugaj, Marcin
Kalawa, Wojciech
Grabowska, Karolina
Chaja, Patryk Robert
Sosnowski, Marcin
Nowak, Wojciech
Mika, Łukasz
Bykuć, Sebastian
Powiązania:
https://bibliotekanauki.pl/articles/2173577.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
adsorption heat pump
polygeneration
cooling capacity
low grade thermal energy
artificial neural networks
soft computing
absorpcyjna pompa ciepła
poligeneracja
wydajność chłodnicza
energia cieplna niskiej jakości
sztuczne sieci neuronowe
przetwarzanie miękkie
Opis:
Adsorption cooling and desalination technologies have recently received more attention. Adsorption chillers, using eco-friendly refrigerants, provide promising abilities for low-grade waste heat recovery and utilization, especially renewable and waste heat of the near ambient temperature. However, due to the low coefficient of performance (COP) and cooling capacity (CC) of the chillers, they have not been widely commercialized. Although operating in combined heating and cooling (HC) systems, adsorption chillers allow more efficient conversion and management of low-grade sources of thermal energy, their operation is still not sufficiently recognized, and the improvement of their performance is still a challenging task. The paper introduces an artificial intelligence (AI) approach for the optimization study of a two-bed adsorption chiller operating in an existing combined HC system, driven by low-temperature heat from cogeneration. Artificial neural networks are employed to develop a model that allows estimating the behavior of the chiller. Two crucial energy efficiency and performance indicators of the adsorption chiller, i.e., CC and the COP, are examined during the study for different operating sceneries and a wide range of operating conditions. Thus this work provides useful guidance for the operating conditions of the adsorption chiller integrated into the HC system. For the considered range of input parameters, the highest CC and COP are equal to 12.7 and 0.65 kW, respectively. The developed model, based on the neurocomputing approach, constitutes an easy-to-use and powerful optimization tool for the adsorption chiller operating in the complex HC system.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 3; art. no. e137054
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the conditions for the exhaustion of the stability margin in the rail track of freight cars with three-piece bogies
Autorzy:
Domin, Yurii V.
Domin, Rostysla Yu.
Cherniak, Ganna Yu.
Nozhenko, Volodymyr S.
Powiązania:
https://bibliotekanauki.pl/articles/1833607.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
freight cars
derailment
traffic safety
dynamic performance
computer simulation
wagony towarowe
wykolejenie
bezpieczeństwo na drodze
wydajność dynamiczna
symulacja komputerowa
Opis:
The research on improvement of methodical approaches to definition of the probable reasons of infringement of conditions of stability of freight cars from derailment is carried out. Using a basic computer model of the dynamics of a freight car, the influence of the characteristics of the technical condition of their running gear and track on the indicators of empty cars stability from derailment was studied through the computational experiment. The article presents the main statements of the research methodology, which provides the analysis of probable causes of derailment of freight cars by conducting a series of numerical experiments with logging the progress of calculations and saving the results. Factor analysis was used to interpret the calculated data with an assessment of each of the factors influence or their combination on the probability of derailment. The developed procedure of the simulation experiment provides a step-by-step study of the freight cars derailment conditions, including factors structuring and ranking, development of experimental plan, calculating coefficients of wheel pairs resistance to derailment from rails, provided that the wheel flange rolls onto the rail head, and determining the degree of influence of relevant factors on the dynamic stability of cars from derailment. A comparative analysis of the stability of cars in rail tracks was performed using the introduced concept of the combined coefficient of stability of wheel pairs against derailment. Determining the probable causes of car derailment is based on scanning the parameter field. The results of the parametric study revealed the degree of influence on the freight cars stability of running gear technical condition characteristics. In particular, it is determined that the most dangerous in terms of stability loss of empty cars in the track is the exceeding of the wedges of the vibration dampers.
Źródło:
Archives of Transport; 2021, 57, 1; 119-129
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The performance of tramway service from the users viewpoint: A comparative analysis between two Moroccan cities
Autorzy:
Zehmed, Karim
Jawab, Fouad
Powiązania:
https://bibliotekanauki.pl/articles/2067395.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
tramway service
performance
perceived quality
satisfaction
Morocco
comparative analysis
komunikacja tramwajowa
wydajność
postrzegana jakość
Maroko
analiza porównawcza
Opis:
The Moroccan government has recently promoted sustainable public transport projects such as tramway services namely in the two largest cities of country, Casablanca and Rabat-Salé. Since its launch, the tramway service is increasingly present in citizens' daily lives in both cities. To maintain its attractiveness, operators and transport authorities should examine the performance of tramway service from user’s point of view. That is, an in-depth understanding of how passengers perceive service quality and what make them satisfied. The purpose of this study is to compare the performance of tramway service in the two cities based on the opinions of a sample size of 613 and 435 individuals in each city. The outcome of this peer comparison allows to determine the strengths and weaknesses of provided service and identify priorities for improvement in each city. Regarding the methodology, we adopted a two-step approach to achieve our research purpose. The first stage intends to compare users' perceptions regarding Service Quality Attributes (SQAs) and overall satisfaction and to identify any significant differences between the two cities. To this end, we applied, in the first stage, a student t-test of two independent samples. The second stage employs an ordered probit regression model to identify the most important SQA; i.e., which most influence the overall satisfaction, and improvements priorities for the current service tramway. The results showed that, in average, passengers found service quality as good and are satisfied with tramway service in both cities. Tram vehicles’ is the best appreciated service attribute in both cities while Comfort in Rabat-Salé and Lines’ connectivity in Casablanca are the least appreciated. Moreover, the service performance of Rabat-Salé tramway exceeds that of Casablanca tramway in terms of service Availability, service Reliability, Fares level, Tram vehicle, Drivers’ competence, Lines’ connectivity, and overall satisfaction. On the other hand, we found that among top six important attributes, Reliability and Administrators should be prioritized for improvement in Casablanca; and staff, Lines, Comfort, and Administrators in Rabat-Salé. Results showed that improvements in all these service aspects would increase significantly overall user’s satisfaction.
Źródło:
Archives of Transport; 2021, 60, 4; 7--21
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The performance of tramway service from the users viewpoint: A comparative analysis between two Moroccan cities
Autorzy:
Zehmed, Karim
Jawab, Fouad
Powiązania:
https://bibliotekanauki.pl/articles/2067398.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
tramway service
performance
perceived quality
satisfaction
Morocco
comparative analysis
komunikacja tramwajowa
wydajność
postrzegana jakość
Maroko
analiza porównawcza
Opis:
The Moroccan government has recently promoted sustainable public transport projects such as tramway services namely in the two largest cities of country, Casablanca and Rabat-Salé. Since its launch, the tramway service is increasingly present in citizens' daily lives in both cities. To maintain its attractiveness, operators and transport authorities should examine the performance of tramway service from user’s point of view. That is, an in-depth understanding of how passengers perceive service quality and what make them satisfied. The purpose of this study is to compare the performance of tramway service in the two cities based on the opinions of a sample size of 613 and 435 individuals in each city. The outcome of this peer comparison allows to determine the strengths and weaknesses of provided service and identify priorities for improvement in each city. Regarding the methodology, we adopted a two-step approach to achieve our research purpose. The first stage intends to compare users' perceptions regarding Service Quality Attributes (SQAs) and overall satisfaction and to identify any significant differences between the two cities. To this end, we applied, in the first stage, a student t-test of two independent samples. The second stage employs an ordered probit regression model to identify the most important SQA; i.e., which most influence the overall satisfaction, and improvements priorities for the current service tramway. The results showed that, in average, passengers found service quality as good and are satisfied with tramway service in both cities. Tram vehicles’ is the best appreciated service attribute in both cities while Comfort in Rabat-Salé and Lines’ connectivity in Casablanca are the least appreciated. Moreover, the service performance of Rabat-Salé tramway exceeds that of Casablanca tramway in terms of service Availability, service Reliability, Fares level, Tram vehicle, Drivers’ competence, Lines’ connectivity, and overall satisfaction. On the other hand, we found that among top six important attributes, Reliability and Administrators should be prioritized for improvement in Casablanca; and staff, Lines, Comfort, and Administrators in Rabat-Salé. Results showed that improvements in all these service aspects would increase significantly overall user’s satisfaction.
Źródło:
Archives of Transport; 2021, 60, 4; 7--21
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The slewing drive system for tower crane with permanent magnet synchronous motor
Autorzy:
Knypiński, Łukasz
Krupiński, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/1841337.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
energy conversion efficiency
permanent magnet synchronous motor
slewing drive system
system efficiency
tower cranes
efektywność konwersji energii
silnik synchroniczny z magnesami trwałymi
obrotowy układ napędowy
wydajność systemu
żurawie wieżowe
Opis:
The paper presents a method of determining the efficiency of the slewing drive system applied in tower cranes. An algorithm for the proper selection of a permanent magnet synchronous motor (PMSM) for crane applications is presented. In the first stage of our research the proper PMSM was proposed on the basis of the simulation calculation. Next, the PM motor was examined on a special test bench. The experimental setup allows determining major electrical and mechanical parameters of the motor drive system. The applied slewing system consists of: an inverter, gear, cable drum and a permanent magnet motor. The performance and efficiency of the system were experimentally determined. Selected results of the experimental measurement are presented and discussed.
Źródło:
Archives of Electrical Engineering; 2021, 70, 1; 189-201
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Use of natural dyes for the fabrication of dye-sensitized solar cell: a review
Autorzy:
Bhargava, Cherry
Sharma, Pardeep Kumar
Powiązania:
https://bibliotekanauki.pl/articles/2086868.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
DSSC
dye-sensitized solar cell
efficiency
natural dye
performance
synthetic dye
ogniwo słoneczne uczulane barwnikiem
wydajność
barwnik naturalny
barwnik syntetyczny
Opis:
The increasing concern for worldwide energy production is the result of global industrialization and decreasing energy resources. Despite the cost factor, solar energy continues to become more popular due to its long-term nature as a resource and growing conversion efficiency. A dye-sensitized solar cell converts visible light into electricity. The efficient use of dye as a sensitizer is the critical factor in enhancing the performance of the dye-sensitized solar cell. Natural dyes are found in abundance in leaves, flower petals, roots, and other natural resources. Due to the advantages of natural dyes such as cost-effectiveness, the simpler extraction process, and being environmentally friendly, etc., researchers are working extensively to replace synthetic dyes with natural ones. This paper highlights the various types of natural dyes and their effect on the efficiency of the dye-sensitized solar cell.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 6; e139319, 1--12
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of labour efficiency supported by the ensembles of neural networks on the example of steel reinforcement works
Analiza wydjaności pracy wspomagana zespołem sieci neuronowych na przykładzie robót zbrojarskich
Autorzy:
Juszczyk, Michał
Powiązania:
https://bibliotekanauki.pl/articles/230439.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wydajność pracy
sieć neuronowa
prognoza
roboty zbrojarskie
zbrojenie stalowe
labour efficiency
neural network
prediction
reinforcement works
steel reinforcement
Opis:
This study presents an artificial intelligence technique based on ensemble of artificial neural networks for the purposes of analysis and prediction of labour productivity. The study focuses on the development of model that combines several artificial neural networks on the basis of real-life data collected on a construction site for steel reinforcement works. The data includes conditions, characteristics, features of steel reinforcement works and related efficiencies of workers assigned to particular tasks recorded on site. The proposed ensemble based model combines five supervised learning models - five different multilayer perceptron networks, which contribution in the prediction is weighted due to the application of generalised averaging approach. Testing results show that the proposed ensemble based model achieves the satisfactory evaluation criteria for coefficient of correlation (0.989), root-mean-squared error (2.548), mean absolute percentage error (4.65%) and maximum absolute percentage error (8.98%).
Wydajność pracy ma kluczowy wpływ na czas realizacji i koszty przedsięwzięć budowlanych. W publikacji przedstawiono wyniki prac badawczych nad wykorzystaniem zespołów sztucznych sieci neuronowych w analizie i predykcji wydajności pracy na przykładzie robot zbrojarskich. Analiza została przeprowadzona w oparciu dane zbierane przez wykonawcę w trakcie realizacji robót. Celem pracy badawczej była ocena przydatności danych zebranych przez wykonawcę robot oraz proponowanego narzędzia matematycznego do analizy i predykcji wydajności pracy.
Źródło:
Archives of Civil Engineering; 2020, 66, 1; 97-111
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The efficiency of food supply chain engineering (case study in Ukraine)
Autorzy:
Kush, Yevhen
Tonkoshkur, Maksym
Vakulenko, Kateryna
Ryabev, Anton
Davidich, Natalia
Galkin, Andrii
Powiązania:
https://bibliotekanauki.pl/articles/1833669.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
material flow
direct channel
supply chain
food supply engineering
present value
efficiency
przepływ materiałów
kanał bezpośredni
łańcuch dostaw
inżynieria dostaw żywności
wartość
wydajność
Opis:
The basic conceptual idea of logistics is the need to adapt the company to an ever-changing market situation, while spending a minimum of funds in these conditions. The concept of logistics is a system of views on the rationalization of economic activity by optimizing material flows. The paper investigates the change of the main indicators of the functioning of the supply chain, depending on the organization of distribution of the material flow. The supply systems of food products that form the consumer basket at the stage of distribution is considered. The conceptual schemes of freight flow distribution with and without distribution center is presented. The field research was conducted to determine and initial data were collected. The paper investigate the functioning of the supply chain in two cases: in a situation "proposed scenario" and in a situation "without a project". The situation "existing scenario" implies that no action to change the parameters of the supply chain during the period specified for the research does not take place. In this case, it is necessary to assess the effectiveness of the logistics chain under existing conditions. An integrated approach to evaluate the efficiency of the functioning of the logistics system and the consumer had been used. The efficiency of existing of the supply chain functioning were analysed. Also, certain measures will be implemented to improve the chain through investments and by bringing logistics infrastructure with the needs. A modelling of the supply chain was made. The effect of parameters of participants on the supply chain efficiency was analysed. The planned effect from the reorganization of distribution channels is calculated. The technological and economic feasibility of introducing a distribution center into the existing distribution channel based on modeling is calculated. The object of the research is the process of food products distribution in the supply chain. The aim of the research is to evaluate the effectiveness of the food supply chain scheme.
Źródło:
Archives of Transport; 2020, 55, 3; 51-71
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of start energy of Stirling engine type alpha
Autorzy:
Kropiwnicki, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/240606.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Stirling engines
system efficiency
low temperature supply
silniki Sterlinga
wydajność systemu
zasilanie
niska temperatura
Opis:
The Stirling engine type alpha is composed of two cylinders (expansion space E and compression space C), regenerator that forms the space between the cylinders and the buffer space (under the pistons). Before the start-up and as a result of long-term operation, the average pressure in the working space (above the pistons) and in the buffer space is the same. However, in the initial phase of operation, the average pressure in the working space is different then the average pressure in the buffer space depending on the crankshaft starting position (starting angle). This, in turn, causes a large variation in the starting torque. An additional unfavorable factor caused by a large variation in the course of the indicated torque is the rotational speed variation and the formation of torsional vibrations in the drive system. After some time, depending on the quality of the engine piston sealing, the average pressure in the working and buffer space will equalize. The occurrence of the above-described phenomenon affects the selection of the starting electric motor, which can be significantly reduced, when the crankshaft starting position is optimized (the starting torque is several times greater than the average torque occurring in the generator operation mode). This paper presents the analysis of the impact of the crankshaft starting position on the course of the indicated torque and the resulting start-up energy. Starting the engine at an unfavorable position of the crankshaft may, in extreme cases, increase the starting torque even three times.
Źródło:
Archives of Thermodynamics; 2019, 40, 3; 243-259
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 73

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies