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1
Content available Problem of the road network capacity
EN
The perception of a typical user of the road network in a large Polish city is determined by the time he spends in queues and congestion every day. In the opinion of many users of this network, it is too long. This time ranges from several to several dozen minutes. In order to explain the dysfunction in question, the concept of physical and transportation capacity of the road network has been described. Then, the basic numerical characteristics of the Polish road network in selected small and voivodship cities have been presented. The analysis used basic data on the length of the road network, the number of inhabitants and the “motorization” indicator for the cities analysed in the article. In this context, reference was also made to commonly used ways to improve the functioning of the road network, from traffic lights, through roundabouts, to ITS (Intelligent transport systems). The summary presents, in the context of new technical solutions in the field of transport systems, the perspective of the functioning of road networks for the next 20‑30 years.
PL
Percepcja typowego użytkownika sieci drogowej w dużym polskim mieście, determinowana jest czasem, który codziennie spędza on w kolejkach i zatorach. W opinii wielu użytkowników tej sieci jest on zbyt duży. Czas ten wynosi od kilkunastu do kilkudziesięciu minut. W celu wyjaśnienia przedmiotowej dysfunkcjonalności, opisano pojęcie pojemności fizycznej i komunikacyjnej sieci drogowej. Następnie przytoczono bazowe charakterystyki liczbowe polskiej sieci drogowej w wybranych miastach powiatowych oraz wojewódzkich. W analizie wykorzystano podstawowe dane w zakresie długości sieci drogowej, liczby mieszkańców i wskaźnik motoryzacji dla miast analizowanych w artykule. W tym kontekście, odniesiono się również do powszechnie stosowanych sposobów poprawy funkcjonowania sieci drogowej poczynając od sygnalizacji świetlnej, poprzez ronda a skończywszy na systemach ITS (ang. Intelligent transport systems). W podsumowaniu zaprezentowano, w kontekście nowych rozwiązań technicznych w obszarze systemów transportowych, perspektywę funkcjonowania sieci drogowych na najbliższe 20-30 lat.
EN
A wireless sensor system is an essential aspect in many fields. It consists of a great deal of sensor nodes. These sensor networks carry out a number of tasks, including interaction, distribution, recognition, and power supply. Data is transmitted from source to destination and plays an important role. Congestion may occur during data transmission from one node to another and also at cluster head locations. Congestion will arise as a result of either traffic division or resource allocation. Energy will be wasted due to traffic division congestion, which causes packet loss and retransmission of removed packets. As a result, it must be simplified; hence there are a few Wireless sensor networks with various protocols that will handle Congestion Control. The Deterministic Energy Efficient Clustering (DEC) protocol, which is fully based on residual energy and the token bucket method, is being investigated as a way to increase the energy efficiency. In the event of congestion, our proposal provides a way to cope with it and solves it using this method to improve lifespan of the sensor networks. Experiments in simulation show that the proposed strategy can significantly enhance lifetime, energy, throughput, and packet loss.
EN
With the continuous urban expansion of cities around the world, cities have become more crowded as the numbers of all kinds of vehicles have increased, especially due to the inclination of individuals to use personal cars. In this study, we want to identify the different reasons that motivate the populations of the state of Skikda, Algeria, to prefer using cars through a questionnaire. In order to be clearer, we processed and analyzed the survey data using the SPSS analytical program. This article aims to identify the main reasons that motivate individuals to prefer using a personal car when traveling and propose possible solutions, or even identify actions to be taken now and in the future in order to establish a more sustainable exclusive transport. By analyzing the results, it became clear to us that road users prefer cars only for psychological and technical reasons and do not consider the preservation of the environment or the security of people. Although they are aware of the problems arising from their extensive use, they continue to do so because they have no other alternative. Improvements in public transportation means would change the situation.
4
Content available remote Intensywność obciążenia mostów drogowych w sytuacji zatoru
PL
W pracy analizowano bezpieczeństwo mostów drogowych w trakcie ich eksploatacji w sytuacji maksymalnego obciążenia. Takie obciążenia mostów występują podczas badań odbiorczych obiektu gdy programowany jest układ samochodów na jezdni. Rozpatrywaną w pracy jest sytuacja pełnego obciążenia mostów występująca w trakcie zatoru drogowego. Wówczas układ pojazdów jest z natury rzeczy losowy a kilka z nich może tworzyć układ maksymalnego, lokalnego obciążenia. Rezultaty pomiarów podczas rzeczywistego zatoru powstałego na moście o schemacie podwieszonym odniesiono do wyników analiz numerycznych. Przyjęto dwubelkowy model przęsła i dwujezdniowy układu obciążenia w zatorze. Jako przypadek skrajny rozpatrzono w pracy obciążenie od dwóch pojazdów ale w małym moście. Do analiz porównawczych wykorzystano algorytm obciążenia zastępczego.
EN
The work analyzed the safety of road bridges during their exploitation in the situation of maximum load. Such bridge loads occur during acceptance tests of the object when the system of cars on the roadway is programmed. Considered in the work is the situation of full load on bridges occurring during a road congestion. Then the layout of the vehicles is inherently random and several of them can form a system of maximum, local load. The results of measurements during the actual congestion created on the bridge with a suspended diagram were related to the results of numerical analyzes. A two-beam span model and a dual carriageway load system in the congestion were adopted. As an extreme case, the load from two vehicles was considered at work, but in a small bridge. A replacement load algorithm was used for comparative analysis.
EN
Expressway emergencies tend to cause traffic congestion, and understanding the travel time delays of on-road vehicles under different combinations of event scenarios and road traffic conditions is valuable for guiding the accurate emergency dispatch services. Most existing studies used methods that combine the Lighthill-Whitham-Richards (LWR) theory and basic traffic diagrams to solve this problem, but the discrete traffic flow characteristics caused by the presence of heavy vehicles have not been considered, thus affecting the applicability of those results to road traffic characteristics in China. Moreover, there is a lack of systematic research on multiple combinations of unexpected event scenarios and traffic conditions, and the guidance value of the previously obtained results is limited. In order to improve the applicability of the prediction model and accurately predict the severity of emergencies, based on a logistic model that is applicable to emergencies, a velocity–density model is constructed to describe discrete traffic flow characteristics. Based on LWR theory, the internal driving force of expressway traffic state evolution under emergency conditions is explored. Combined with real-time traffic flow data, the parameters of the logistic model are calibrated, and a logistic velocity-density model is constructed using a goodness-of-fit test and a marching method, including the free-flow velocity, turning density and heavy vehicle mixing ratio. Thus, the problem that existing models lack applicability to road traffic characteristics in China is solved. Travel time delay is associated with the impact range of an emergency, and it is an effective index for evaluating the severity of emergency incidents. Thus, the travel time delays under different scenarios, different numbers of blocked lanes and different orthogonal combinations of approximate saturation conditions are explored, and the impacts of lane blockage on emergency incidents and travel time delays are obtained. The conclusions show that the presented logistic velocity-density model constructed based on discrete traffic flow characteristics can properly quantify the impact of the presence of heavy vehicles. Additionally, the results can provide theoretical support for handling emergencies and emergency rescues.
6
Content available Detecting congestion in DEA by solving one model
EN
The presence of input congestion is one of the key issues that result in lower efficiency and performance in decision-making units (DMUs). So, determination of congestion is of prime importance, and removing it improves the performance of DMUs. One of the most appropriate methods for detecting congestion is Data Envelopment Analysis (DEA). Since the output of inefficient units can be increased by keeping the input constant through projecting on the weak efficiency frontier, it is unnecessary to determine the congested inefficient DMUs. Therefore, in this case, we solely determine congested vertex units. Towards this aim, only one LP model in DEA is proposed and the status of congestion (strong congestion and weak congestion) obtained. In our method, a vertex unit under evaluation is eliminated from the production technology, and then, if there exists an activity that belongs to the production technology with lower inputs and higher outputs compared with the omitted unit, we say vertex unit evidences congestion. One of the features of our model is that by solving only one LP model and with easier and fewer calculations compared to other methods, congested units can be identified. Data set obtained from Japanese chain stores for a period of 27 years is used to demonstrate the applicability of the proposed model and the results are compared with some previous methods.
EN
In this paper we consider a link, characterized by specific capacity, that services multi-rate random or quasirandom traffic. Random traffic is generated by an infinite number of traffic sources, while quasi-random traffic is generated by a finite population of traffic sources. The link is modeled as a multi-rate loss system. Handover and new calls are distinguished. New calls compete for the available bandwidth under a threshold call admission policy. In that policy, a new call of a particular service-class is not allowed to enter the system if the in-service handover and new calls of the same service-class plus the new call, exceed a predefined threshold (which can be different for each service-class). On the other hand, handover calls compete for the available bandwidth based on the complete sharing policy. We show that the steady state probabilities in the proposed models have a product form solution (PFS). The PFS leads to a convolution algorithm for accurate calculation of congestion probabilities and link utilization.
EN
In the article, a validation module, being a component of an integrated system supporting routing in software defined networks (SDNRoute), is proposed and thoroughly examined. The module allows for the verification of the results provided by the optimization module before these results are deployed in the production network. Routing policies are validated for their impact on the network quality parameters and against the threat of overloading (congestion).
EN
We consider the downlink of an orthogonal frequency division multiplexing (OFDM) based cell that accommodates calls from different service-classes with different resource requirements. We assume that calls arrive in the cell according to a quasi-random process, i.e., calls are generated by a finite number of sources. To calculate the most important performance metrics in this OFDM-based cell, i.e., congestion probabilities and resource utilization, we model it as a multirate loss model, show that the steady-state probabilities have a product form solution (PFS) and propose recursive formulas which reduce the complexity of the calculations. In addition, we study the bandwidth reservation (BR) policy which can be used in order to reserve subcarriers in favor of calls with high subcarrier requirements. The existence of the BR policy destroys the PFS of the steady-state probabilities. However, it is shown that there are recursive formulas for the determination of the various performance measures. The accuracy of the proposed formulas is verified via simulation and found to be satisfactory.
PL
Zatłoczenie miast jest jednym z największych problemów obecnej polityki transportowej. Odpowiednie jej kształtowanie pozwoli ograniczyć zjawisko zatłoczenia, czyli kongestii. Często możemy obserwować prace związanie z dobudowaniem pasów ruchu czy powstaniem nowych ulic. Czy jednak taki stan rzeczy prowadzi do polepszenia szybkości przemieszczania się do wyznaczonego celu, szczególnie w tak zwanych godzinach szczytu? Otóż okazuje się, że nie. Posługując się takim rozumowaniem, miasto nie staje się przyjazne ludziom, lecz samochodom. Warto więc skorzystać z rozwiązań już sprawdzonych.
EN
City congestion is one of the biggest problems in today's transport policy. Its appropriate shaping will allow to limit the phenomenon of congestion. We can often observe work related to the addition of lanes or creation of new streets. However, does such a state of affairs lead to the improvement of the speed of movement to the designated destination, especially during the so-called rush hours? Well, it turns out not. Using this reasoning, the city does not become friendly to people, but to cars. So let's use the already proven solutions.
EN
This paper proposes a multiobjective improved particle swarm optimisation (IPSO) for placing and sizing the series modular multilevel converter-based unified power flow controller (MMC-UPFC) FACTS devices to manage the transmission congestion and voltage profile in deregulated electricity markets. The proposed multiobjective IPSO algorithm is perfect for accomplishing the close ideal distributed generation (DG) sizes while conveying smooth assembly qualities contrasted with another existing algorithm. It tends to be reasoned that voltage profile and genuine power misfortunes have generous upgrades along ideal speculation on DGs in both the test frameworks. The proposed system eliminates the congestion and the power system can be easily used to solve complex and non-linear optimisation problems in a real-time manner.
EN
The aim of the study was to assess the content of Ca, Mg, Na and K in the road dust collected in Białystok from various environments (roads with high traffic intensity, housing estate roads, roads located near parks and green areas), in order to determine the impact of the road transport on the spatial differentiation of the content of the tested components in street dust and identify their main sources. In total, the samples from 69 points were analyzed, which were taken in spring 2018 (late April and May) during the dry weather. The content of Ca, Mg, Na and K was determined by means of atomic absorption spectrometry (AAS). The average contents of the tested elements in the dust from all measuring points were in the following order: Ca (23.53%) > Mg (2.38) > Na (1.16) > K (0.25). This shows that Ca is the most numerous element in the tested dusts. Studies have not shown a significant impact of vehicle traffic, in particular the so-called non-exhaust sources related to this traffic on the content of main elements in the Białystok road dusts. The analyses have indicated that the main source of Ca and Mg in the Białystok road dust constitute the structural elements of roads, bridges and structures, in which building cement and its derivatives are the main component.
EN
The economic development of Poland depends on a modern, effective and safe transport system. It is dependent on proper legal regulations both Polish and EU. They give an opportunity to develop innovative urban logistics or electromobility. The aim of the article is to analyze EU and Polish legal regulations regarding innovative public transport, as well as to present development prospects for electromobility.
PL
Rozwój gospodarczy Polski zależy od nowoczesnego, efektywnego i bezpiecznego systemu transportu. Uzależniony on jest od właściwych regulacji prawnych zarówno polskich, jak i unijnych. Dają one szansę na rozwój innowacyjnej logistyki miejskiej czy elektromobilności. Celem artykułu jest analiza unijnych i polskich regulacji prawnych dotyczących innowacyjnego transportu publicznego, a także przedstawienie perspektyw rozwojowych elektromobilności.
PL
W pracy przedstawione zostało znaczenie inteligentnych systemów transportowych w różnych środowiskach i przykłady ich użycia. Zastosowano metody badawcze takie, jak studium literatury, case study, analiza desk research, obserwacje, wywiad oraz ankieta. Wprowadzenie ITS wpływa pozytywnie na transport drogowy. Zauważyć to można na przykładzie miasta Białystok – prekursora wdrażania nowoczesnych systemów w Polsce. Wypracowane zostały oszczędności, wzrósł stopień bezpieczeństwa i osiągnięto niższy poziom kongestii. W artykule przedstawiono również sytuację firm transportowych i ich zdanie na temat rozwiązań użytych na drogach. Polscy przedsiębiorcy w dalszym ciągu korzystają z tradycyjnych metod kontaktu między pracownikami. Wprowadzenie inteligentnych systemów transportowych, pomimo konieczności inwestycji na etapie wdrażania, przynosi oszczędności i daje długofalowe efekty.
EN
The paper presents the importance of intelligent transport systems in different environments and examples of their use. Research methods were applied, i.e. literature study, case study, desk research analysis, observations, interview and questionnaire. The introduction of ITS has a positive impact on road transport. This can be noticed on the example of the city of Białystok – a precursor of the implementation of modern systems in Poland. Savings have been achieved, the level of safety has increased and a lower level of congestion has been achieved. The article also presents the situation of transport companies and their opinion on the solutions used on the roads. Polish entrepreneurs continue to use traditional methods of contact between employees. The introduction of intelligent transport systems, despite the need to invest at the implementation stage, brings savings and long- -term effects.
15
Content available Transport miejski w dobie inteligentnych miast
PL
Celem artykułu jest przedstawienie głównych problemów transportu miejskiego, z którymi borykają się mieszkańcy współczesnych metropolii. Rosnące niezadowolenie społeczeństwa, niska przepustowość miejskich układów drogowych oraz zwiększający się poziom zanieczyszczenia powietrza - to tylko wybrane niedogodności ograniczające rozwój obszarów zurbanizowanych. Naprzeciw tym problemom wychodzi idea Smart City, dążąca do usprawnienia i rozwoju branży TSL. W referacie przedstawiono innowacyjne technologie, poprawiające jakość życia ludności oraz ułatwiające kreowanie przestrzeni miejskiej.
EN
The aim of the article is to present the main problems related to urban transport faced by the in habitants of modern metropolitan areas. Increasing dissatisfaction of the society, low capacity of urban road systems and increasing level of air pollution - these are just some of the disadvantages that limit the development of urbanized areas. Here comes the idea of Smart City, striving to improve and develop the TFL sector. This paper presents innovative technologies that can improve the quality of life of people and facilitate the creation of urban space.
EN
This paper typically applied the concept of ranking by inspection using the dwell time of ships in five African ports to evaluate the variations in ship turnaround time and relative efficiency level. This is to identify the active factors that cause port congestion in African ports. The results provided some explanations on the consequences arising from these on notable African logistics and supply chain networks. The findings reveal that the bane of congestion in African ports emanates entirely from either planning, regulation, capacity, efficiency or a combination of these. The regression analysis with IBM SPSS v20 reveals that there is a significant relationship between cargo throughput and other port performance indicators in Nigeria for the study period (2005 - 2014). More so, the t-test reveals that there is a significant relationship between cargo throughput and berth occupancy rate which is significantly indicative of port congestion. This paper therefore recommends that African ports should enhance their regulatory mechanisms, and also improve capacity and efficiency level in order to shoulder the ever increasing challenges of port congestion in years ahead.
17
Content available remote Wykorzystanie car-poolingu w przeciwdziałaniu kongestii w transporcie miejskim
PL
Zjawisko kongestii pojawia się w sytuacji, w której popyt na usługi transportowe lub na elementy infrastruktury transportowej przekracza ich wydolność. Utracona w ten sposób płynność przemieszczania generuje problemy zarówno w sferze życia publicznego jak i gospodarki. Dlatego stale poszukiwane są nowe rozwiązania, mogące poprawić przepustowość miast. Sposobem zmniejszania liczby samochodów na drogach jest korzystanie z transportu publicznego, ale także z jego nowoczesnych alternatyw, takich jak car-pooling czy car -shering, które zostały zaprezentowane w niniejszym artykule.
EN
The phenomenon of congestion arises where demand for transport services or transport infrastructure components exceeds their efficiency. The loss of smoothness of movement generates problems both in the sphere of public life and the economy. Therefore, new solutions are constantly being sought, which can improve the capacity of cities. The way to reduce the number of cars on the road is to use public transport, but also with its modern alternatives such as car-pooling or car-shering, which were presented in this article.
PL
Zjawisko kongestii w miastach wpływa negatywnie na płynność przemieszczania, stanowiąc utrudnienie nie tylko dla obywateli, ale również dla rozwoju gospodarki, powodując zakłócenia w łańcuchu dostaw. Zwalczenie tego problemu wymaga indywidualnego podejścia, jednak istnieją pewne rozwiązania w zakresie infrastruktury, a także organizacyjno-techniczne, służące przeciwdziałaniu kongestii w transporcie, możliwe do zaadoptowania w większości miast. Wybrane z nich zostały przedstawione w niniejszym artykule.
EN
The congestion phenomenon in cities has a negative effect on the smoothness of movement, making it difficult not only for citizens but also for the development of the economy, causing disruption in the supply chain. The eradication of this problem requires an individual approach, but there are certain infrastructure solutions, as well as organisational and technical measures to tackle congestion transport, which can be adapted in most cities. The selected ones are presented in this article.
PL
Celem niniejszego artykułu jest syntetyczne przedstawienie koncepcji strefowych (kordonowych) opłat kongestyjnych, których zastosowanie – poprzez adekwatne odzwierciedlenie kosztów odbywanych przez użytkowników systemu transportowego podróży – wpływa na ich zachowania transportowe. Przedstawiony jest więc dorobek teorii ekonomii w zakresie identyfikacji, analizy i internalizacji kosztów zewnętrznych w transporcie stanowiący bazę teoretyczną zastosowania tego typu rozwiązania. Na tej podstawie, w kontekście wskazanego całościowego podejścia do zarządzania przepływami osób, dóbr i informacji na obszarze miasta, analizowane są zależności i powiązania między opłatami kongestyjnymi a logistyką miejską.
EN
The goal of this paper is to present the concept of area (cordon) congestion charges, application of which by adequate reflection of people’s travel costs, affects their travel choices, thus reducing the level of congestion and the associated negative externalities. Therefore the economic theory developments on identifying, analyzing and internalizing externalities in transport that constitute a theoretical framework for usage of such solution are being presented. Based on that the relationships and correlations between congestion charges and city logistics are analyzed in the context of the required holistic approach to the management of people, goods and information flows in the city.
PL
Z problemem kongestii mierzy się wiele miast i aglomeracji miejskich bez względu na ich wielkość i liczbę mieszkańców. Jednakże rozlewanie się obszarów miejskich poza granice administracyjne miast tzw. „urban sprawl” oraz silne tendencje do tworzenia obszarów metropolitalnych problem kongestii pogłębia. Przeciętne miesięczne opóźnienie wywołane kongestią w godzinach szczytu w 2015 roku dla 7 największych miast Polski wyniosło 10 godzin. Kongestia stanowi istotny problem nie tylko dla społeczeństwa, wpływając na mobilność i zwiększając koszty przemieszczania się, ale przede wszystkim zwiększając koszty funkcjonowania gospodarki. W 2015 roku koszty kongestii dla gospodarki wzrosły o 12,5% w porównaniu do roku poprzedniego. W artykule zaprezentowano związki metropolizacji z powstawaniem, skutkami i kosztami kongestii.
EN
The congestion is a problem for many cities and urban areas irrespective of their size and number of inhabitants. However, the spillover of areas beyond the administrative boundaries of urban sprawl and the strong tendency to create metropolitan areas even deepens the problem of congestion. The average monthly congestion delay in 2015 for the 7 largest Polish cities was 10 hours. In 2015 the cost of congestion for the economy increased by 12.5% compared to the previous year. This paper presents metropolitan relations with the origins, consequences, and costs of congestion.
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