Wyniki wyszukiwania - BazTech

1

Saturated arterial coordinate control strategy optimization considering macroscopic fundamental diagram

Lin Xuanhua, Lin Xiaohui, Chen Kelian

Archives of Transport

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2022

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Vol. 62, iss. 2

73--90

EN

MFD is widely used in traffic state evaluation because of its description of the macro level of urban road network. Aiming at the control strategy optimization problem of urban arterial road network under saturated traffic flow state, this study analyzes the MFD characteristics of a typical three-segment "ascending-stable-descending segment" and its advantages in characterizing the macroscopic operation efficiency of the road network, a arterial coordination control strategy considering MFD is proposed. According to the characteristics of MFD, it is proposed that the slope of the ascending segment and the capacity of the road network represent the operating efficiency of the free flow and saturated flow of the road network respectively. The traffic flow and density data of road segment are obtained by the road detector through Vissim simulation software. Aiming at the problem that the MFD is too discrete due to unreasonable control strategy or traffic condition, and in order to extract the MFD optimization target indicators, it is proposed to extract the key boundary points of the MFD by the “tic-tac-toe” method and divide the MFD state by Gaussian mixture clustering. The genetic algorithm integrates the multi-objective particle swarm algorithm as the solution algorithm, and the simulation iterative process is completed through Python programming and the com interface of Vissim software. In order to verify the validity of the model and algorithm, the actual three-intersections arterial road network is used for verification, and the model in this study is compared with the optimization model without considering MFD, the model solved by traditional algebraic method, and the optimization model solved by typical multi-objective particle swarm. Results show that the model in this research performs well in efficiency indicators such as total delay, average delay, and queue coefficient. At the same time, the MFD form has highest stability, the control effect is the best in the saturated state. The solution algorithm GA-MOPSO also has a better solution effect.

2

Fusion splicing: the penalty of increasing the collapse length of the air holes in ESM-12B photonic crystal fibers

Adnan S. A., Abdulwahhab A. W., Ismail S.N.

Optica Applicata

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2016

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Vol. 46, nr 2

265--275

EN

For optimum fusion splicing process of a photonic crystal fiber, the collapsing of the air holes at any photonic crystal fiber is the key point of either increasing or decreasing the total splice loss. In this paper, an experimental study has been carried out to investigate the relation between total splice loss or total fiber attenuation due to splice loss and the length of the collapsed region of the air holes. This is done by splicing ESM-12B photonic crystal fiber between two equal lengths of single mode fibers and measuring the attenuation at different arc times and arc powers. The results showed that the increase in the length of the collapsed air holes region results in higher loss, therefore, higher fiber attenuation.

3

Use of lidar data and selected algorithms for determining the flow lines

Szczepaniak-Kołtun Z

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2015

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nr 18(2)

137--147

EN

This elaboration shows how to use Height Data by using airborne laser scanning (ALS) to delineation of flow lines which let to evaluation of water’s flow on terrain. Maps, which show flow lines, were generated by using GIS software and tools on testing areas. To achieve this goal were used methods of a single flow direction and multiple flow direction. Created maps which show directions of runoff, generated based on the DTM, were subjected to analysis. On the basis of these maps were evaluated the accuracy of determination of the flow direction on the testing areas by using individual algorithms. Studies determining directions of runoff can and do have large application. They will serve the author as initium to create a network of watercourses needed to convert 3D image. This model of the network 3D will be an attempt to create a component BDOT10k in the form of three-dimensional.

4

Koncepcja pomiaru odległości w radarze pasywnym wykorzystującym mikrofalowe dyskryminatory fazy i częstotliwości

Rutkowski A. K.

Elektronika : konstrukcje, technologie, zastosowania

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2014

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Vol. 55, nr 11

85-89

PL

Radar pasywny jest systemem wykrywającym i lokalizującym obiekty przy użyciu sygnałów mikrofalowych emitowanych przez nadajniki niewspółpracujące. Bieżąca analiza parametrów sygnałów mikrofalowych występujących w monitorowanej przestrzeni pozwala wykryć moment pojawienia się obiektu oraz określić jego chwilowe położenie. W podstawowych warunkach radar pasywny detekuje tylko fakt pojawienia się obiektu w obserwowanej przestrzeni. Dla pełnej informacji o wykrytym obiekcie niezbędne jest określenie nie tylko jego kierunku położenia, ale również odległość do niego. Do analizy parametrów sygnałów echa oraz do namierzania obiektów, które te sygnały odbiły można wykorzystać mikrofalowe dyskryminatory fazy MDF i mikrofalowe dyskryminatory częstotliwości MDCz, realizowane sprzętowo lub programowo po uprzedniej konwersji odebranych sygnałów na postać cyfrową. W pracy przedstawiono koncepcję algorytmu pomiaru odległości w radarze pasywnym opartą na wyznaczaniu obwiedni, chwilowej częstotliwości oraz kąta nadejścia odebranych sygnałów odbitych. Opisana koncepcja została przygotowana na potrzeby opracowywanego systemu obserwacji małego zasięgu.

EN

The passive radar uses so called signals of opportunity emitted by noncooperative illuminators such as, for instance, RTV broadcasting station or base station of cellular telecommunication and even active radar. The received signals analysis makes possible the detection of objects appearance and determination their location in the space being monitored. First of all, passive radar gives an information if any objects exists or not. For complete information it is necessary to know not only the direction to the object but the distance to it as well. The microwave phase discriminators and microwave frequency discriminators are very useful for determination parameters of received echo signals and for estimation of direction to the objects. In the work a concept of algorithm of estimation the distance in the single passive radar was presented. This concept is based on: estimation of envelope of the received microwave signal, estimation of the momentary value of the frequency of this signal and angle of arrival AOA of the received microwave signal. This algorithm is useful especially for short distance passive radar.