10 research outputs found
Implementation of Background Subtraction and Fuzzy Logic Control for Green-Timing Optimization on 3-Junction Traffic Light
This study presents a green-timing optimization simulation on a 3-lane traffic light to reduce the density of the vehicle queue (density) in each lane. The method used in green-timing optimization is a combination of background subtraction and fuzzy logic control. Background subtraction functions as density extractor and fuzzy logic control as the green-timing controller itself. Green-timing optimization simulations in this study show a decrease in waiting time in each cycle of timing and a decrease in traffic-density of 44% -45% compared to a fixed-time timing system
Research on Traffic Signal Timing Method Based on Ant Colony Algorithm and Fuzzy Control Theory
The number of private cars has a blowout growth with the development of economics, which leads to the existing limited traffic resources cannot meet the normal traffic demand. The emergence of intelligent traffic has improved this phenomenon. Using intelligent traffic technology to conduct intersection vehicles can alleviate the congestion effectively. Traffic signal timing method plays an important role in intelligent traffic research. An independent intersection dynamic timing method combined with fuzzy control theory and improved ant colony algorithm is proposed in this paper. According to the characteristics of traffic flow distribution, the timing period is obtained with the improved webster algorithm. Through the optimal solution obtained by ant colony algorithm and the added delay of traffic signal calculated by fuzzy control method, the dynamic timing period of the traffic signal is obtained. The validity of the proposed method is proved by comparing with the original time period and the traditional algorithm
An Optimization Approach for Energy Efficient Coordination Control of Vehicles in Merging Highways
Environmental concerns along with stronger governmental regulations regarding automotive fuel-economy and greenhouse-gas emissions are contributing to the push for development of more sustainable transportation technologies. Furthermore, the widespread use of the automobile gives rise to other issues such as traffic congestion and increasing traffic accidents. Consequently, two main goals of new technologies are the reduction of vehicle fuel consumption and emissions and the reduction of traffic congestion. While an extensive list of published work addresses the problem of fuel consumption reduction by optimizing the vehicle powertrain operations, particularly in the case of hybrid electric vehicles (HEV), approaches like eco-driving and traffic coordination have been studied more recently as alternative methods that can, in addition, address the problem of traffic congestion and traffic accidents reduction. This dissertation builds on some of those approaches, with particular emphasis on autonomous vehicle coordination control. In this direction, the objective is to derive an optimization approach for energy efficient and safe coordination control of vehicles in merging highways. Most of the current optimization-based centralized approaches to this problem are solved numerically, at the expense of a high computational load which limits their potential for real-time implementation. In addition, closed-form solutions, which are desired to facilitate traffic analysis and the development of approaches to address interconnected merging/intersection points and achieve further traffic improvements at the road-network level, are very limited in the literature. In this dissertation, through the application of the Pontryagin’s minimum principle, a closed-form solution is obtained which allows the implementation of a real-time centralized optimal control for fleets of vehicles. The results of applying the proposed framework show that the system can reduce the fuel consumption by up to 50% and the travel time by an average of 6.9% with respect to a scenario with not coordination strategy. By integrating the traffic coordination scheme with in-vehicle energy management, a two level optimization system is achieved which allows assessing the benefits of integrating hybrid electric vehicles into the road network. Regarding in-vehicle energy optimization, four methods are developed to improve the tuning process of the equivalent consumption optimization strategy (ECMS). First, two model predictive control (MPC)-based strategies are implemented and the results show improvements in the efficiency obtained with the standard ECMS implementation. On the other hand, the research efforts focus in performing analysis of the engine and electric motor operating points which can lead to the optimal tuning of the ECMS with reduced iterations. Two approaches are evaluated and even though the results in fuel economy are slightly worse than those for the standard ECMS, they show potential to significantly reduce the tuning time of the ECMS. Additionally, the benefits of having less aggressive driving profiles on different powertrain technologies such as conventional, plug-in hybrid and electric vehicles are studied
Applying Machine Learning Techniques to Improve Safety and Mobility of Urban Transportation Systems Using Infrastructure- and Vehicle-Based Sensors
The importance of sensing technologies in the field of transportation is ever increasing. Rapid improvements of cloud computing, Internet of Vehicles (IoV), and intelligent transport system (ITS) enables fast acquisition of sensor data with immediate processing. Machine learning algorithms provide a way to classify or predict outcomes in a selective and timely fashion. High accuracy and increased volatility are the main features of various learning algorithms. In this dissertation, we aim to use infrastructure- and vehicle-based sensors to improve safety and mobility of urban transportation systems. Smartphone sensors were used in the first study to estimate vehicle trajectory using lane change classification. It addresses the research gap in trajectory estimation since all previous studies focused on estimating trajectories at roadway segments only. Being a mobile application-based system, it can readily be used as on-board unit emulators in vehicles that have little or no connectivity. Secondly, smartphone sensors were also used to identify several transportation modes. While this has been studied extensively in the last decade, our method integrates a data augmentation method to overcome the class imbalance problem. Results show that using a balanced dataset improves the classification accuracy of transportation modes. Thirdly, infrastructure-based sensors like the loop detectors and video detectors were used to predict traffic signal states. This system can aid in resolving the complex signal retiming steps that is conventionally used to improve the performance of an intersection. The methodology was transferred to a different intersection where excellent results were achieved. Fourthly, magnetic vehicle detection system (MVDS) was used to generate traffic patterns in crash and non-crash events. Variational Autoencoder was used for the first time in this study as a data generation tool. The results related to sensitivity and specificity were improved by up to 8% as compared to other state-of-the-art data augmentation methods
Microssimulação para avaliar o impacto da introdução de pré-semáforos em cruzamentos
Dissertação de mestrado em Engenharia de SistemasA resolução de problemas relacionados com a saturação dos cruzamentos consiste,
geralmente, na construção de infraestruturas como pontes e túneis. Estas representam o tipo de
soluções mais dispendiosas e, no cenário de crise em que vários países se encontram, torna-se
necessário equacionar outro tipo de soluções, de menor custo. Assim, esta dissertação pretende
fornecer uma resposta à tese de que é possível melhorar significativamente o desempenho de
um cruzamento, através da utilização de pré-semáforos, nos acessos ao mesmo.
Para este efeito, foi desenvolvido um modelo de microssimulação de tráfego, usando o
SIMIO. Durante o processo de familiarização com esta ferramenta, foi efetuada uma comparação
com o Arena. O modelo de tráfego desenvolvido é totalmente parametrizável, sendo possível
alterar: o tipo de cruzamento (com ou sem pré-semáforos); a distância entre um pré-semáforo e
os respetivos semáforos principais; o tempo de sinal verde dos semáforos e a intensidade de
tráfego. Os dados introduzidos para modelar o sistema foram recolhidos através de observações
no terreno e da bibliografia consultada. Definiram-se como KPI (Key Performance Indicators): o
tempo médio de espera por veículo, o tamanho médio das filas e o fluxo de veículos por hora.
Foi usado o modo de experiências de simulação do SIMIO, para avaliar o impacto que as
alterações às propriedades do modelo produzem nos KPI. As experiências indicam que o tempo
adequado de duração do sinal verde, em cruzamentos com pré-semáforos, se deve situar entre
os 20 e os 30 segundos e que o melhor desempenho é atingido quando os pré-semáforos se
encontram a 40 metros dos respetivos semáforos principais, contudo, constata-se que, para
intensidades de tráfego moderadas ou baixas, a distância não influencia o desempenho do
cruzamento. Comparando os desempenhos de um cruzamento com pré-semáforos com o de um
com normal semaforização, verifica-se uma subida do teto máximo do fluxo do cruzamento em
15%, uma descida do tempo médio de espera em aproximadamente 1 minuto e 15 segundos e
uma descida do tamanho médio das filas em aproximadamente 60 metros. Adicionalmente,
também se verificou que existe sempre lucro no espaço ocupado pelas filas, tendo em conta o
investimento necessário para implementação de pré-semáforos.The resolution of problems related to the saturation of traffic intersections usually
consists in the construction of infrastructure such as bridges or tunnels. These represent the type
of solutions most costly and, in the scenario of crisis in which several countries are, it becomes
necessary to ponder another type of solution, of lower cost. Thus, this dissertation intends to
provide an answer to the thesis that it is possible to significantly improve the performance of a
traffic intersection, by using pre-signals, in its approaches.
For this purpose, a traffic micro simulation model was developed, using SIMIO. During
the process of familiarization with this tool, a comparison was made with Arena. The traffic model
developed is completely parametrizable, being possible to change: the type of intersection (with
or without pre-signals); the distance between a pre-signal and the respective main lights of each
approach; the green light signal time of the traffic lights and the traffic intensity. The input data to
model the system were collected through field observations and literature reviewed. The defined
KPI (Key Performance Indicators) were: the average waiting time per vehicle, the average size of
the queues and the flow of vehicles per hour.
To evaluate the impact that changes to the model properties produce on the KPI, the
simulation experiences mode of the SIMIO were used. These show that the proper time duration
of the green light at traffic intersections with pre-signals should be between 20 and 30 seconds
and that the best performance is achieved when the pre-signals are located 40 meters away of
the respective main lights, however, it is found that for moderate and low traffic intensities the
distance doesn‘t influence the performance of the intersection. Comparing the performance of an
intersection with traffic signals with a normal one, it is noted an increase of the upper ceiling of
the flow of the intersection in 15%, a decrease in the average waiting time in approximately 1
minute and 15 seconds and a decrease of the average size of the queues in about 60 meters. In
addition, it was also found that there is always gain in the space occupied by the queues, taking
into consideration the investment needed to implement pre-signals
Security and Privacy for Modern Wireless Communication Systems
The aim of this reprint focuses on the latest protocol research, software/hardware development and implementation, and system architecture design in addressing emerging security and privacy issues for modern wireless communication networks. Relevant topics include, but are not limited to, the following: deep-learning-based security and privacy design; covert communications; information-theoretical foundations for advanced security and privacy techniques; lightweight cryptography for power constrained networks; physical layer key generation; prototypes and testbeds for security and privacy solutions; encryption and decryption algorithm for low-latency constrained networks; security protocols for modern wireless communication networks; network intrusion detection; physical layer design with security consideration; anonymity in data transmission; vulnerabilities in security and privacy in modern wireless communication networks; challenges of security and privacy in node–edge–cloud computation; security and privacy design for low-power wide-area IoT networks; security and privacy design for vehicle networks; security and privacy design for underwater communications networks
Quality management of postal service using geometric modeling
Предмет истраживања у оквиру докторске дисертације представљају модели за управљање и унапређење квалитета поштанске услуге. Квалитет је једна од најистакнутијих одредница производа и услуга. Има веома значајан утицај на одлуку потенцијалних купаца о куповини, односно потенцијалних корисника о коришћењу одређене услуге. Савремено тржиште, под утицајем развијене конкуренције, иницира код сваког субјекта тежњу у смеру унапређења нивоа квалитета. Са друге стране, постизање вишег нивоа квалитета, по правилу захтева одређена улагања и искоришћење одговарајућих ресурса. Проналазак оптималног баланса, представља један од основних циљева процеса управљања квалитетом. У складу са наведеним, важно је дефинисати одговарајући модел за подршку одлучивању. У оквиру докторске дисертације, предложена су два модела за управљање квалитетом, заснована на примени геометријског моделирања: Geometric Model for Quality Management-Subjectivity - GMQM-S, који поред показатеља перформанси (вредности показатеља параметара квалитета) уважава и субјективна мишљења; Geometric Model for Quality Management-Performance - GMQM-P - заснован само на показатељима перформанси (вредностима показатеља параметара квалитета). Резултат примене ових модела, јесте формирање полиедара, чија запремина представља репрезенте нивоа квалитета. На овај начин, постиже се визуелизација нивоа квалитета, која се може квантификовати, што омогућује једноставнију анализу, а самим тим и управљање. Процес унапређења квалитета услуге, захтева примену одговарајућег стратешког приступа, како би се успешно и по приоритетима лоцирали и издвојили баш они сегменти у пословном систему, којима је унапређење потребно, односно како би се дефинисале активности унапређења које је потребно реализовати. У дисертацији је предложен одговарајући модел за унапређење квалитета услуге и пословних процеса - А'ВА (AHP-Business Areas). Заснован је на комбинованој примени AHP (Analytic Hierarchy Process) методе и теорије пословних области. Представља унапређење, претходно развијене, модификоване A’WOT (AHP и SWOT) методе. Саставни део овог приступа је 2D геометријски модел за подршку вишекритеријумском одлучивању (GMCDM – Geometric Model as a Support for Multiple Criteria Decision Making). Један од основних циљева истраживања јесте илустрација применљивости предложених модела за управљање и унапређење квалитета на примеру поштанске услуге. Студија случаја је реализована на примеру ЈП „Пошта Србије“, кроз три фазе реализације: одређивање нивоа квалитета услуге за тренутно стање у систему; примена модела за унапређење квалитета услуге и предлог одговарајућих активности; одређивање нивоа квалитета услуге након спровођења предложених активности. Поређење резултата из прве и треће фазе указује на ефекат имплементације активности предложених у другој фази, које су формиране у складу са резултатима примене дефинисаног стратешког приступа. Примена модела за унапређење квалитета, односно стратешког приступа, у великој мери је дефинисала и структуру дисертације. Наиме, у складу са резултатима, издвојила су се четири правца, која су посебно обрађена: организација доставе; ефикасност прераде пошиљака; претоварне манипулације; асортиман услуга. Детаљном анализом, указале су се смернице за предлог четири главне активности унапређења: територијална организација доставе; унапређење ефикасности мануелне прераде пошиљака; увођење концепта и решавање задатка 3D packing problem-a у поштанском саобраћају; увођење нове услуге (“Post Express non-stop” – временска доступност 24 часа дневно). У циљу сагледавања ефеката имплементације предложених активности, односно утицаја реинжењеринга на пословни процес, посматрани су одговарајући показатељи, претходно дефинисаних параметара квалитета. Показатељи су добијени пре свега на основу реализованих рачунарских симулација, мишљења експерата, запослених у ситему и корисника. Резултати примене геометријских модела управљања квалитетом, показали су успешност предложених активности у циљу унапређења нивоа квалитета. Анализа осетљивости, указала је на различите сценарије утицаја анализираних параметара на ниво квалитета услуге, односно на могућности управљања квалитетом.The subject of research of the doctoral dissertation is models for managing and improving quality of postal services. Quality is one of the most prominent determinants of products and services. It has a very significant influence on the decision of potential buyers about the purchase, or potential users about using a particular service. The modern market initiates overall tendency towards the improvement of the quality level, through the influence of the developed competition. On the other hand, achieving a higher level of quality, as a rule, requires certain investments and the utilization of appropriate resources. Finding the optimal balance is one of the main goals of the quality management process. In line with the above stated, it is vital to define an appropriate model to achieve that. Within the dissertation, two models for quality management are proposed, both based on the application of geometric modeling: Geometric Model for Quality Management-Substance - GMQM-S, which in addition to performance indicators (values of quality parameters) also takes into account personal views and Geometric Model for Quality Management-Performance - GMQM-P – which is based only on the performance indicators (values of quality parameters). The result of using these models is the formation of polyhedron, whose volume represents the level of quality. In this way, the quality level visualization is achieved and it can be quantified, which makes it easier to analyze and therefore, to manage. Process of service quality improvement requires an appropriate strategic approach in order to locate, successfully and by priorities, as well as to identify segments in the business system that need improvement, that is in order to define improvement activities that need to be implemented. In the dissertation, an appropriate model for improving the service quality and business processes is proposed: A'BA (AHP-Business Areas). It is based on the combined use of AHP (Analytic Hierarchy Process) method and theory of business areas. It represents improved, previously developed, modified A'WOT (AHP and SWOT) methods. An integral part of this approach is a 2D geometric model to support multi-criteria decision making (GMCDM - Geometric Model as a Support for Multiple Criteria Decision Making). One of the main objectives of the survey is to illustrate the applicability of the proposed models for quality management and improvement in the case of postal services. The case study was carried out on the example of the public company "Post of Serbia", in three stages: determining the level of service quality for the current situation in the system; applying the model for service quality improvement and suggesting appropriate activities; determining the level of service quality after implementing the proposed activities. Comparison of the results from the first and the third phase indicates the effect of the implementation of the activities proposed in the second phase, which were formed in accordance with the results of the defined strategic approach that has been applied. The use of the quality improvement model, or the strategic approach, has largely defined the structure of this dissertation. Namely, in accordance with the results, there have been four directions singled out and then handled separately: organization of delivery; efficiency of shipment processing; overloading manipulations; assortment of services. Detailed analysis showed guidelines for four main improvement activities: territorial organization of delivery; improving efficiency of manual processing of packages; introducing the concept and solving the 3D packing problem in postal traffic; introduction of a new service ("Post Express non-stop" - time availability 24 hours per day). With an aim to examine the effects of the implementation of the proposed activities, that is, the impact of reengineering on the business process, appropriate indicators of previously defined quality parameters were observed. The indicators were obtained primarily on the basis of performed computer simulations and opinions of experts, employees in the system and users. The results of quality management geometric models used, pointed to the success of the proposed activities in order to improve the quality level. The sensitivity analysis showed different scenarios of the influence of analyzed parameters to the service quality level, that is, on quality management potentials
Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields
Innovations in Road, Railway and Airfield Bearing Capacity – Volume 2 comprises the second part of contributions to the 11th International Conference on Bearing Capacity of Roads, Railways and Airfields (2022). In anticipation of the event, it unveils state-of-the-art information and research on the latest policies, traffic loading measurements, in-situ measurements and condition surveys, functional testing, deflection measurement evaluation, structural performance prediction for pavements and tracks, new construction and rehabilitation design systems, frost affected areas, drainage and environmental effects, reinforcement, traditional and recycled materials, full scale testing and on case histories of road, railways and airfields. This edited work is intended for a global audience of road, railway and airfield engineers, researchers and consultants, as well as building and maintenance companies looking to further upgrade their practices in the field
2014, UMaine News Press Releases
This is a catalog of press releases put out by the University of Maine Division of Marketing and Communications between January 6, 2014 and December 31, 2014