Estimating and exploiting the capacity of urban street networks

The paper deals with the problem of estimating and exploiting traffic capacity of different road elements (link, nodes, network) and presents the results obtained by performing a systematic investigation of the role that the parameters of a microscopic simulation model play on the macroscopic representation of different road elements. An analysis of traffic parameters has been performed using a microsimulation software package to identify the most important parameters affecting the arterial capacity and to calibrate driver's behavior models through macroscopic traffic observations

Optical, vibrational, thermal, electrical, damage and phase-matching properties of lithium thioindate

Lithium thioindate (LiInS$_{2}$) is a new nonlinear chalcogenide biaxial material transparent from 0.4 to 12 $\mu$m, that has been successfully grown in large sizes and good optical quality. We report on new physical properties that are relevant for laser and nonlinear optics applications. With respect to AgGaS(e)$_2$ ternary chalcopyrite materials, LiInS$_{2}$ displays a nearly-isotropic thermal expansion behavior, a 5-times larger thermal conductivity associated with high optical damage thresholds, and an extremely low intensity-dependent absorption allowing direct high-power downconversion from the near-IR to the deep mid-IR. Continuous-wave difference-frequency generation (5-11$\mu$m) of Ti:sapphire laser sources is reported for the first time.Comment: 27 pages, 21 figures. Replaces the previous preprint (physics/0307082) with the final version as it will be published in J. Opt. Soc. Am. B 21(11) (Nov. 2004 issue

Analysis of vibration loads to space manipulation system by the carrier rocket

One of the categories of ensuring robot reliability – mechanical strength. The robot must be resistant to a variety of impacts, aimed at its destruction, for example any emergency situation or inadvertent influence of the person. In case of space robotic systems also need to sustain the severe vibration stresses arising at launch and landing. One way to check robot to withstand vibration stresses - testing on a vibration table. However, breakage during vibration testing requires considerable time and financial expenses for redesign the robot, restoration of damaged parts and re-testing. This can be avoided by pre-conducting vibration simulation. Modeling identifies the most vulnerable in the mechanical sense of detail and allows engineers the opportunity to make timely changes to the project. This report highlight the work of the vibration simulation of space manipulation system, show the results of calculations, schedules and distribution charts of surface stresses. Vibrational modeling is an important condition for creating high-quality products and can save considerable resources in development and manufacturing of systems for space purposes. Development of methods for evaluation of vibration disturbances on products designed to operate in space is of great interest for the creators of such technology.Одна из категорий обеспечения надёжности робота – механическая прочность. Робот должен быть устойчив к различным воздействиям, направленным на его разрушение, например возникновению некой аварийной ситуации или непреднамеренному воздействию человека. В случае с космическими робототехническими системами так же необходимо обеспечить устойчивость к серьёзным вибрационным нагрузкам, возникающим при взлете и посадке. Одним из способов установить способность робота противостоять вибрационным нагрузкам является проведение испытаний на вибростенде. Однако в случае неудачи на этапе вибрационных испытаний требуются значительные временные и финансовые затраты на изменение конструкции робота, восстановление повреждённых деталей и повторное проведение испытаний. Избежать этого можно при проведении вибрационного моделирования в процессе конструирования робота. Моделирование выявляет наиболее уязвимые в механическом смысле детали и позволяет разработчикам своевременно внести изменения в конструкцию. В статье рассмотрена работа по вибрационному моделированию манипуляционной системы космического назначения, на примере которой показаны результаты расчётов, графики и карты распределения поверхностных напряжений

Comparative analysis of implicit models for real-time short-term traffic predictions

Predicting future traffic conditions in real-time is a crucial issue for applications of intelligent transportation systems devoted to traffic management and traveller information. The increasing number of connected vehicles equipped with locating technologies provides a ubiquitous updated source of information on the whole network. This offers great opportunities for developing data-driven models that extrapolate short-term future trend directly from data without modelling traffic phenomenon explicitly. Among several different approaches to implicit modelling, machinelearning models based on a network structure are expected to be more suitable to catch traffic phenomenon because of their capability to account for spatial correlations existing between traffic measures taken on different elements of the road network. The study analyses and applies different implicit models for short-term prediction on a large road network: namely, time-dependent artificial neural networks and Bayesian networks. These models are validated and compared by exploiting a large database of link speeds recorded on the metropolitan area of Rome during seven months. © The Institution of Engineering and Technology 2016

Роль инженера И.Г. Александрова в использовании энергетических ресурсов Ангары (30-ые годы ХХ века)

У статті висвітлюється внесок інженера і академіка І.Г. Александрова (1875-1936) у вирішення проблем енергетичного забезпечення Східного Сибіру. Показано роль ріки Ангара у становленні народного господарства СРСР. Проблема Ангари в наукових працях І.Г. Александрова переросла у проблему докорінного перетворення усього Східного Сибіру. У розробках проблеми Ангари І.Г. Александров не залишав поза своєї уваги питання розвитку культури населення Східного Сибіру, який кардинально змінював свій вигляд після спорудження великих енергетичних і промислових підприємств. Науковець та інженер, він, тим не менше, наголошував на необхідності створення сприятливих побутових умов для людей, пов’язаних прямо чи опосередковано з індустріальним прогресуванням краю. Іван Гаврилович розглядав проблему Ангаро-Єнісею не тільки як учений та інженер, але і як державний діяч, який дбає про те, щоб посилення технічної і економічної могутності країни вело до зростання добробуту і культури населення.In the article the contribution of engineer and academician І.H. Aleksandrov (1875-1936) to the solution of the power providing problems in Eastern Siberia has been highlighted. The article describes the role of the Angara river in the USSR national economy forming as well. The Angara problem in І.H. Aleksandrov’s scientific research papers turned into the problem of radical transformations in the whole Eastern Siberia. Working out the Angara problem solutions І.H. Aleksandrov paid much attention to developing the Eastern Siberia population’s culture due to its drastic changes after the erection of great power and industrial plants. Being a scientist and an engineer, І.H. Aleksandrov, nevertheless, stressed the necessity of creating proper living conditions for people connected directly or indirectly with industrial advancements of the region. Ivan Havrylovych Aleksandrov considered the problem of Angara and the Yenisey basin not only as a scientist or engineer, but also as a statesman who took care of technical and economic strengthening of the country leading to growth of people’s welfare and culture.В статье освещается вклад инженера и академика І.Г. Александрова (1875-1936) в решение проблем энергетического обеспечения Восточной Сибири. Показана роль реки Ангара в становлении народного хозяйства СССР. Проблема Ангары в научных трудах І.Г. Александрова переросла в проблему коренного преобразования всей Восточной Сибири. В разработках проблемы Ангары І.Г. Александров не выпускал из поля зрения вопросы развития культуры населения Восточной Сибири, которая кардинально изменяла свой вид после сооружения больших энергетических и промышленных предприятий. Научный работник и инженер, он, тем не менее, отмечал необходимость создания благоприятных бытовых условий для людей, связанных прямо или опосредовано с индустриальным прогрессом края. Иван Гавриилович рассматривал проблему Ангаро-Енисея не только как ученый и инженер, но и как государственный деятель, который заботится о том, чтобы усиление технического и экономического могущества страны вело к росту благосостояния и культуры населения

A Simulation-Optimization Method for Signal Synchronization with Bus Priority and Driver Speed Advisory to Connected Vehicles

The paper introduces a model-based optimization procedure for the design of a control system with signal synchronization, real-time bus priority and green light speed advisory to car drivers. The traffic model simulates car traffic as platoons and bus movements individually. An optimization routine simulates the effect of different bus priority rules, which can be actuated online through bus identification devices and applies a metaheuristic algorithm to optimize signal settings. The macroscopic model and the design method have been applied and also tested in microsimulation on a principal street in Rome with a tram line on a reserved lane. Results obtained show that offline signal optimization and online signal priority can significantly reduce both travel times of bus riders and delays for total traffic. Similarly, speed advisory to drivers, if considered in signal optimization, can improve not only drivers' delays but even transit passengers' delays because it allows more efficient use of the road

Modeling Car following with Feed-Forward and Long-Short Term Memory Neural Networks

The paper investigates the capability of modeling the car following behavior by training shallow and deep recurrent neural networks to reproduce observed driving profiles, collected in several experiments with pairs of GPS-equipped vehicles running in typical urban traffic conditions. The input variables are relative speed, spacing, and vehicle speed. In the model, we assume that the reaction is not instantaneous. However, it may occur during a time interval of the order of a few tenth of seconds because of both the psychophysical driver’s reaction process and the mechanical activation of braking or dispensing the traction power to the wheels. Experimental results confirm the reliability of this assumption and highlight that the deep recurrent neural network outperforms the simpler feed-forward neural network

Analysis of Road Safety Speed from Floating Car Data

Intelligent Transportation Systems aims at improving efficiency and safety of the transportation system by acting either on vehicle performances or assisting the driver with information on vehicle and traffic status. Although digital road graphs are available to derive quantitative parameters that describe the road geometry, the information provided usually includes speed limits and repetition of road signs. On the other hand, a huge amount of data is available on individual vehicle speeds and trajectories collected as Floating Car Data (FCD) but they are not combined with road parameters to derive information on how drivers perceive the infrastructure and behave when traveling on it. In the paper, a methodology is presented to evaluate the consistency between drivers' behavior and a theoretical safety speed determined from road geometry. The azimuth profile is progressively built for a road layout, based on the geometry described by a digital graph. Consecutive elements with the constant azimuth variation are identified as circular curves and their radii are computed by circle fitting. The safety speed with respect to longitudinal stability is estimated. The obtained safety speed is then compared to the distribution of speeds observed from about 200 million FCD collected on the regional road network of Latium. The obtained results permit to individuate critical points of the network in terms of road safety