scholarly journals An Empirical Framework for Intersection Optimization Based on Uniform Design

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Ying Zhang ◽  
Daniel Jian Sun ◽  
Alexandra Kondyli

Operational performance optimization of signalized intersections is one of the most important tasks for traffic engineers and researchers. To compensate for the limitations of practical implementation, simulation software packages have been widely used to evaluate different optimization strategies and thus to improve the efficiency of the intersections as well as the entire network. However, for the existing optimization studies on signalized intersections, the relationships among various optimization measures and the combination of strategies have not been fully investigated. In this paper, uniform design experimentation was introduced to combine different optimization measures into strategies and achieve the minimum time cost in model construction. VISSIM software package was then calibrated and used to evaluate various optimization strategies and identify the one with the best measurement of performance, namely, control delay at the signalized intersection. By taking a representative congested intersection in Shanghai as a case study, the optimal strategy was identified to reduce the overall control delay by 27.3%, which further verified the modeling capability of the proposed method.

2014 ◽  
Vol 708 ◽  
pp. 167-172
Author(s):  
Pavol Božek ◽  
Marek Kňažík ◽  
Vladimír Štollmann

The paper describes one practical implementation of the Digital Factory concept – design of a new production line using modern planning method of virtual testing and control of processes. The project covered graphical facility design, detailed design of operations and material flow simulation. This case study shows facility process planning, commission and in the end finding the optimization rules and corrective actions to increase existing casting line throughput. All phases of the project were carried out using simulation software, duration of the project was 6 months. Simulation software WITNESS has been used for material flow simulation.


2021 ◽  
Vol 12 (1) ◽  
pp. 256
Author(s):  
Julio Alberto Ramírez-Montañez ◽  
Marco Antonio Aceves-Fernández ◽  
Jesús Carlos Pedraza-Ortega ◽  
Efrén Gorrostieta-Hurtado ◽  
Artemio Sotomayor-Olmedo

Understanding the behavior of suspended pollutants in the atmosphere has become of paramount importance to determine air quality. For this purpose, a variety of simulation software packages and a large number of algorithms have been used. Among these techniques, recurrent deep neural networks (RNN) have been used lately. These are capable of learning to imitate the chaotic behavior of a set of continuous data over time. In the present work, the results obtained from implementing three different RNNs working with the same structure are compared. These RNNs are long-short term memory network (LSTM), a recurrent gated unit (GRU), and the Elman network, taking as a case study the records of particulate matter PM10 and PM2.5 from 2005 to 2019 of Mexico City, obtained from the Red Automatica de Monitoreo Ambiental (RAMA) database. The results were compared for these three topologies in execution time, root mean square error (RMSE), and correlation coefficient (CC) metrics.


2017 ◽  
Vol 18 (4) ◽  
pp. 599-618 ◽  
Author(s):  
Dragisa STANUJKIC ◽  
Edmundas Kazimieras ZAVADSKAS ◽  
Darjan KARABASEVIC ◽  
Zenonas TURSKIS ◽  
Violeta KERŠULIENĖ

Groups are generally considered to be more effective as compared to single individuals. The practical implementation of Operation Research methods in group negotiations needs simple contexts and clear cause-and-effect relationships easily discernible by everyone. This paper proposes a multi-criteria group decision-making approach allowing decision makers/experts involved in a negotiation process to better express and defend their preferences in the selection of the best alternative. In the proposed approach, the most appropriate alternative is the alternative with the largest number of appearances in the first position or in ranking lists, or the one determined based on negotiations of decision makers/experts. The proposed ARCAS approach is based on the use of the ARAS method, a new normalization procedure, and the SWARA method. In the proposed approach, each decision maker/expert involved in evaluation has an opportunity to set the preferred level of rating for each criterion used in such evaluation. Finally, a case study is presented in order to highlight the proposed approach. The obtained results confirm the usability and efficiency of the proposed approach.


Author(s):  
C. C. Ahn ◽  
S. Karnes ◽  
M. Lvovsky ◽  
C. M. Garland ◽  
H. A. Atwater ◽  
...  

The bane of CCD imaging systems for transmission electron microscopy at intermediate and high voltages has been their relatively poor modulation transfer function (MTF), or line pair resolution. The problem originates primarily with the phosphor screen. On the one hand, screens should be thick so that as many incident electrons as possible are converted to photons, yielding a high detective quantum efficiency(DQE). The MTF diminishes as a function of scintillator thickness however, and to some extent as a function of fluorescence within the scintillator substrates. Fan has noted that the use of a thin layer of phosphor beneath a self supporting 2μ, thick Al substrate might provide the most appropriate compromise for high DQE and MTF in transmission electron microcscopes which operate at higher voltages. Monte Carlo simulations of high energy electron trajectories reveal that only little beam broadening occurs within this thickness of Al film. Consequently, the MTF is limited predominantly by broadening within the thin phosphor underlayer. There are difficulties however, in the practical implementation of this design, associated mostly with the mechanical stability of the Al support film.


2018 ◽  
Vol 18 (1) ◽  
pp. 46-54
Author(s):  
Irmala Sukendra ◽  
Agus Mulyana ◽  
Imam Sudarmaji

Regardless to the facts that English is being taught to Indonesian students starting from early age, many Indonesian thrive in learning English. They find it quite troublesome for some to acquire the language especially to the level of communicative competence. Although Krashen (1982:10) states that “language acquirers are not usually aware of the fact that they are acquiring language, but are only aware of the fact that they are using the language for communication”, second language acquisition has several obstacles for learners to face and yet the successfulness of mastering the language never surmounts to the one of the native speakers. Learners have never been able to acquire the language as any native speakers do. Mistakes are made and inter-language is unavoidable. McNeili in Ellis (1985, p. 44) mentions that “the mentalist views of L1 acquisition hypothesizes the process of acquisition consists of hypothesis-testing, by which means the grammar of the learner’s mother tongue is related to the principles of the ‘universal grammar’.” Thus this study intends to find out whether the students go through the phase of interlanguage in their attempt to acquire second language and whether their interlanguage forms similar system as postulated by linguists (Krashen).


2018 ◽  
Vol 59 (1) ◽  
pp. 65-79
Author(s):  
Katarzyna Nikorowicz-Zatorska

Abstract The present paper focuses on spatial management regulations in order to carry out investment in the field of airport facilities. The construction, upgrades, and maintenance of airports falls within the area of responsibility of local authorities. This task poses a great challenge in terms of organisation and finances. On the one hand, an active airport is a municipal landmark and drives local economic, social and cultural development, and on the other, the scale of investment often exceeds the capabilities of local authorities. The immediate environment of the airport determines its final use and prosperity. The objective of the paper is to review legislation that affects airports and the surrounding communities. The process of urban planning in Lodz and surrounding areas will be presented as a background to the problem of land use management in the vicinity of the airport. This paper seeks to address the following questions: if and how airports have affected urban planning in Lodz, does the land use around the airport prevent the development of Lodz Airport, and how has the situation changed over the time? It can be assumed that as a result of lack of experience, land resources and size of investments on one hand and legislative dissonance and peculiar practices on the other, aviation infrastructure in Lodz is designed to meet temporary needs and is characterised by achieving short-term goals. Cyclical problems are solved in an intermittent manner and involve all the municipal resources, so there’s little left to secure long-term investments.


2011 ◽  
Vol 1 (3) ◽  
pp. 34-66
Author(s):  
Joyce Valdovinos

The provision of water services has traditionally been considered a responsibility of the state. During the late 1980s, the private sector emerged as a key actor in the provision of public services. Mexico City was no exception to this trend and public authorities awarded service contracts to four private consortia in 1993. Through consideration of this case study, two main questions arise: First, why do public authorities establish partnerships with the private sector? Second, what are the implications of these partnerships for water governance? This article focuses, on the one hand, on the conceptual debate of water as a public and/or private good, while identifying new trends and strategies carried out by private operators. On the other hand, it analyzes the role of the state and its relationships with other actors through a governance model characterized by partnerships and multilevel networks.Spanish La provisión del servicio del agua ha sido tradicionalmente considerada como una responsabilidad del Estado. A finales de la década de 1980, el sector privado emerge como un actor clave en el suministro de servicios públicos. La ciudad de México no escapa a esta tendencia y en 1993 las autoridades públicas firman contratos de servicios con cuatro consorcios privados. A través de este estudio de caso, dos preguntas son planteadas: ¿Por qué las autoridades públicas establecen partenariados con el sector privado? ¿Cuáles son las implicaciones de dichos partenariados en la gobernanza del agua? Este artículo aborda por una parte, el debate conceptual del agua como bien público y/o privado, identificando nuevas tendencias y estrategias de los operadores privados. Por otra parte, se analizan el rol y las relaciones del Estado con otros actores a través de un modelo de gobernanza, definido en términos de partenariados y redes multi-niveles.French Les services de l'eau ont été traditionnellement considérés comme une responsabilité de l'État. À la fin des années 1980, le secteur privé est apparu comme un acteur clé dans la fourniture de certains services publics. La ville de Mexico n'a pas échappé à cette tendance et en 1993, les autorités publiques ont signé des contrats de services avec quatre consortiums privés. À travers cette étude de cas, nous nous interrogerons sur deux aspects : pourquoi les autorités publiques établissentelles des partenariats avec le secteur privé ? Quelles sont les implications de ces partenariats sur la gouvernance de l'eau ? Cet article s'intéresse, d'une part, au débat conceptuel sur l'eau en tant que bien public et/ou privé, en identifiant les tendances nouvelles et les stratégies menées par les opérateurs privés. D'autre part y sont analysés le rôle de l'État et ses relations avec d'autres acteurs à travers un modèle de gouvernance, défini en termes de partenariats, et des réseaux multi-niveaux.


2018 ◽  
Vol 69 (8) ◽  
Author(s):  
Doina Vesa ◽  
Cristian Martu ◽  
Razvan Leata ◽  
Ludmila Lozneanu ◽  
luminita Radulescu ◽  
...  

Paranasal mucoceles are a type of cysts that evolve slowly and are asymptomatic; this poses a difficulty in diagnosing the patient because the symptoms can go unnoticed. The mucocele evolves unpredictably. On the one hand, it can become infected turning into pyoceles and on the other hand, it can invade important regions such as the orbital, cranial or genian regions, creating facial asymmetry. This is a retrospective case study of 37 patients diagnosed with sinus mucoceles, followed up by clinical examination and paraclinical tests such as CT and MRI scans. The biochemical components of the liquid from within the mucocele were analyzed and the following criteria were recorded: NaCl-, Cl-, Na+ and cholesterine as well as cellular components such as mastocytes, macrophages, hematocytes and leucocytes. In all cases, the treatment option was surgery with favorable post-operative and follow-up evaluation. The mucoceles that appeared post-operatively (maxillary and ethmoid sinuses) evolved more rapidly than the mucoceles that were induced byan external injury. Longer follow-up of operated patients permitted a more timely diagnosis of recurrences.


2021 ◽  
pp. 1329878X2199289
Author(s):  
Jay Daniel Thompson ◽  
Denis Muller

This article examines how freedom of speech is framed in the media controversy surrounding the Australian rugby player Israel Folau’s April 2019 Instagram post. A content analysis and framing analysis of newspaper reportage reveals that the controversy has been largely discussed in terms of whether or not Folau’s speech was being curtailed and whether this curtailing indicates a broader, ideologically motivated censoriousness. This discussion is problematic in that it says little about the actual substance of Folau’s post. This article argues that debates surrounding freedom of speech such as the one involving Folau could and should be enriched by an engagement with ethical principles. This engagement is premised on a commitment to the free exchange of views, while acknowledging that ‘speech’ is not always inherently beneficial for democracy, nor worth defending.


Author(s):  
Zihang Wei ◽  
Yunlong Zhang ◽  
Xiaoyu Guo ◽  
Xin Zhang

Through movement capacity is an essential factor used to reflect intersection performance, especially for signalized intersections, where a large proportion of vehicle demand is making through movements. Generally, left-turn spillback is considered a key contributor to affect through movement capacity, and blockage to the left-turn bay is known to decrease left-turn capacity. Previous studies have focused primarily on estimating the through movement capacity under a lagging protected only left-turn (lagging POLT) signal setting, as a left-turn spillback is more likely to happen under such a condition. However, previous studies contained assumptions (e.g., omit spillback), or were dedicated to one specific signal setting. Therefore, in this study, through movement capacity models based on probabilistic modeling of spillback and blockage scenarios are established under four different signal settings (i.e., leading protected only left-turn [leading POLT], lagging left-turn, protected plus permitted left-turn, and permitted plus protected left-turn). Through microscopic simulations, the proposed models are validated, and compared with existing capacity models and the one in the Highway Capacity Manual (HCM). The results of the comparisons demonstrate that the proposed models achieved significant advantages over all the other models and obtained high accuracies in all signal settings. Each proposed model for a given signal setting maintains consistent accuracy across various left-turn bay lengths. The proposed models of this study have the potential to serve as useful tools, for practicing transportation engineers, when determining the appropriate length of a left-turn bay with the consideration of spillback and blockage, and the adequate cycle length with a given bay length.


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