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The Sight Distance Issues with Retrofitted Single-Lane HOV Facilities

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International Journal of transportation Science and Technology 2013年第2期2卷 149-157页

作者： Zhongren Wang division of traffic operations California Department of Transportation 1120 N StreetMS-36SacramentoCA 95814

It is well-known that obstruction inside a highway horizontal curve will lead to impaired sight *** alignment design standards in terms of the minimum horizontal curve radius are specified to allow for adequate stopping sight distance at given design *** a singlelane HOV facility,inside curve obstruction may occur no matter when the facility curves to the left(per travel direction)or right.A unique situation that calls for special attention is that the adjacent mixed-flow lane traffic,once queued,may become sight *** indicated that such obstruction may govern the minimum curve radius design as long as the left shoulder is not less than 0.92 m,when the HOV lane is contiguous to the mixed-flow *** governance may necessitate design speed reduction,horizontal and cross-section design adjustment,or both.

关键词： HOV radius alignment

Ramp Metering Status in california

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International Journal of transportation Science and Technology 2013年第4期2卷 337-350页

作者： Zhongren Wang division of traffic operations california department of transportation 1120 n street MS-36 SacramentoCA 95814

The purpose of this paper is to provide an update of the major improvement in terms of ramp metering design and operations in *** updates include ramp metering policies,ramp metering development plans,ramp metering de... 详细信息

关键词： operations california update

An Evaluation of Ramp Control Signal Head Placement Based on Motorist’s Cone of Visions

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International Journal of transportation Science and Technology 2014年第3期3卷 265-276页

作者： Zhongren Wang Hiep nguyen division of traffic operations California Department of Transportation1120 N StreetMS-36SacramentoCA 95814

Roadside mounted ramp control signals have one upper head,and one lower head in *** upper head is intended for use by the approaching motorists,while the lower one for use by the stopped *** have been received regarding the visibility of these signal *** evaluation presented in this paper is to mathematically analyze the visibility of these signal heads on a tangent roadway alignment based on satisfactory motorists’cones of *** design,signal placement,and driver characteristics are integrated into one analytic *** results indicated that the horizontal satisfactory cone of vision controls the placement *** meet the 20 degree satisfactory horizontal cone of vision as specified by the Manual on Uniform traffic Control Devices(MUTCD),a ramp control signal head has to be placed a minimum of 13.3 m downstream of the limit line.

关键词： mounted approaching specified

A Comparison of Floating Car *** Detector Estimated Freeway Travel Time Delay

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International Journal of transportation Science and Technology 2012年第2期1卷 147-169页

作者： Zhongren Wang Senior transportation Engineer Division of Traffic OperationsCalifornia Department of Transportation1120 N StreetMS-36SacramentoCA 95814

Floating car-and loop detector-based methods are two different types of methods frequently used to collect travel time delay information across a freeway ***,it is necessary to use them jointly to achieve the necessary freeway network coverage,due to the high labor costs for the floating car-based method and the indispensability of sufficient network instrumentation for the loop detector-based *** example,both floating car-and loop detector-based methods were once used in the Highway Congestion Monitoring Program in the california department of *** is therefore necessary to evaluate whether these two types of methods estimate similarly in terms of total travel time *** this end,corresponding delay information estimated using both types of methods from 37 freeway segments in the Greater Sacramento Area were collected and *** was found that these two types of methods do not estimate similarly in terms of total segment travel time *** mean absolute relative difference(MARD)can be as high as 78%,especially when delay is defined using a lower reference speed,such as 56 km/***,in terms of total segment travel time,the loop detector and the modified floating car method estimated *** MARD is 19%.It was also found that the estimation from the different methods did correlate fairly well,which provides a means of conversion when different methods are used to monitor the total delay across a freeway *** a spin-off,it was also found that a 1.5 km spacing of loop detectors is sufficient to achieve the 19%MARD as compared with the modified floating car method in terms of total travel time estimation.

关键词： Freeway Travel Time Delay Floating Car Loop Detector Comparison spacing

A Discussion on the Current MUTCD Standards on traffic Control Signals for Freeway Entrance Ramps

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International Journal of transportation Science and Technology 2012年第1期1卷 73-82页

作者： Zhongren Wang Vinh Dang division of traffic operations California Department of Transportation1120 N StreetMS-36SacramentoCA 95814 nW Region Freeway operations Washington Department of Transportation

In Section 4I.02 of the newly published Manual on Uniform traffic Control Devices(MUTCD),standards were specified for the placement of signal heads for traffic control signals at freeway entrance ramps,or ramp *** simultaneous operations,*** ramp control signals are operated such that green signal indications are always displayed simultaneously to all of the lanes on the ramp,a minimum of two signal faces per ramp shall face entering *** staggered operations,*** ramp control signal are operated such that green signal indications are not always displayed simultaneously to all of the lanes on the ramp,one signal face shall be provided over the approximate center of each separately-controlled *** on a nation-wide survey,it was realized that the two standards did not fully reflect the state-of-the-practice with respect to ramp metering *** to the lack of significant conflicting movements at ramp meters,for any on-ramp lane,a minimum of one overhead mounted,or one upper and one lower roadside-mounted signal face is sufficient to control the metering *** minimum necessary number of signal faces changes according to the total number of lanes,how the signal faces are mounted(overhead or roadside mounting),and how the meters are operated(simultaneous or staggered).Suggestions are made to revise the two standards to better reflect the current nation-wide practices,and better consider the specific operational needs for ramp meters.

关键词： Ramp Meter Signal Head Placement Standard operations

Integrating Visibility,Parking Restriction,and Driver’s Field View for Enhancing Pedestrian Crossing Safety

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International Journal of transportation Science and Technology 2013年第4期2卷 351-355页

作者： Chiu Liu Zhongren Wang california department of transportation 1120 N Street MS-36SacramentoCA 95831

Pedestrians at a marked but unsignalized pedestrian crossing(Ped-Xing)must be made visible to drivers in the approaching traffic at a sufficient distance away from the crossing,and this distance is needed for stopping a vehicle before the leading Ped-Xing edge to avoid a potential traffic *** this paper,an exact analytic framework is established to integrate driver’s field view,driver’s perception-reaction,lighting condition,and parking restriction at a Ped-Xing for enhancing traffic operational *** size of the no parking zone by the Ped-Xing is determined exactly using equations derived from this ***,this study sheds the light on mid-block Ped-Xing installation,which should be discouraged if parking is permitted alongside a ***,additional visibility improvement measures at the unsignalized Ped-Xings may be needed for enhancing safe traffic operations at the crossings.

关键词： Driver visibility approaching

The Minimum Yellow Timing for Ramp Meters

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International Journal of transportation Science and Technology 2014年第4期3卷 365-377页

作者： Zhongren Wang Chiu Liu california department of transportation 2829 Gateway Oaks Dr.Ste.200 MS-91 SacramentoCA 95833 california department of transportation 1120 n street MS-36 SacramentoCA 95814

The minimum Yellow timing is an important timing factor that affects metering rate for multiple-vehicle-per-green,such as two-vehicle-per-green,type of *** review of the current ramp meter timing practices,it was found that the minimum Yellow timing does not consider the dilemma zone issue for the approaching motorists,and therefore may lead to red-light *** analytic framework was developed to determine the minimum Yellow timing by integrating the ramp meter timing logic and dilemma zone removal *** such as roadway geometry,driver and vehicle characteristics,and detector layout are *** two-vehicle-per-green type of operations,an evaluation indicated that the minimum Yellow should be timed around 3.6 seconds to consider the situation when the 2nd vehicle is *** a long but necessary minimum Yellow timing will increase the minimum cycle length to about 7.7 seconds and hence reduce the release capacity by about 10%.

关键词： approaching operations integrating

A data directory to facilitate investigations on worldwide wildlife trafficking

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Big Earth Data 2023年第2期7卷 338-348页

作者： Meredith L.Gore Rowan Hilend Jonathan OPrell Emily Griffin John R.Macdonald Burcu B.Keskin Aaron Ferber Bistra Dilkina department of Geographical Sciences University of MarylandCollege ParkUSA department of Supply Chain Management Michigan State UniversityEast LansingUSA department of Information Sciences Statisticsand Management ScienceUniversity of AlabamaTuscaloosaUSA operations and Information Management division Babson CollegeWellesleyUSA Supply Chain Management Department of ManagementColorado State UniversityFort CollinsUSA Verterbi School of Engineering University of Southern CaliforniaLos AngelesUSA

Wildlife trafficking is a global phenomenon posing many negative impacts on socio-environmental *** exploration of wildlife trafficking trends and the impact of interventions is significantly encumbered by a suite of data reuse *** describe a novel,open-access data directory on wildlife trafficking and a corresponding visualization tool that can be used to identify data for multiple purposes,such as exploring wildlife trafficking hotspots and convergence points with other crime,discovering key drivers or deterrents of wildlife trafficking,and uncovering structural *** searches,expert elicitation,and peer-reviewed publications were used to search for extant sources used by industry and non-profit organizations,as well as those leveraged to publish academic research *** open-access data directory is designed to be a living document and searchable according to multiple *** directory can be instrumental in the data-driven analysis of unsustainable illegal wildlife trade,supply chain structure via link prediction models,the value of demand and supply reduction initiatives via multi-item knapsack problems,or trafficking behavior and transportation choices via network interdiction problems.

关键词： Illegal wildlife trade supply chain operations management interdiction conservation

High-contrast,fast chemical imaging by coherent Raman scattering using a self-synchronized two-colour fibre laser

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Light(Science & Applications) 2020年第1期9卷 1775-1786页

作者： Cihang Kong Christian Pilger Henning Hachmeister Xiaoming Wei Tom H.Cheung Cora S.W.Lai nikki P.Lee Kevin K.Tsia Kenneth K.Y.Wong Thomas Huser department of Electrical and Electronic Engineering The University of Hong KongPokfulam RoadHong KongChina Biomolecular Photonics Department of PhysicsUniversity of BielefeldUniversitatsstr2533615 BielefeldGermany division of Life Science The Hong Kong University of Science and TechnologyHong KongChina department of Physiology Li Ka Shing Faculty of MedicineThe University of Hong KongPokfulamHong KongChina department of Surgery The University of Hong KongPokfulam RoadHong KongChina division of Engineering and Applied Science California Institute of Technology1200 East California BoulevardPasadenaCA 91125USA

Coherent Raman scattering(CRS)microscopy is widely recognized as a powerful tool for tackling biomedical problems based on its chemically specific label-free contrast,high spatial and spectral resolution,and high ***,the clinical translation of CRS imaging technologies has long been hindered by traditional solid-state lasers with environmentally sensitive operations and large *** fibre lasers can potentially overcome these shortcomings but have not yet been fully exploited for CRS imaging,as previous implementations have suffered from high intensity noise,a narrow tuning range and low power,resulting in low image qualities and slow imaging ***,we present a novel high-power self-synchronized two-colour pulsed fibre laser that achieves excellent performance in terms of intensity stability(improved by 50 dB),timing jitter(24.3 fs),average power fluctuation(n depth(>20 dB)and pulse width variation(n extended wavenumber range(2700-3550 cm^(−1)).The versatility of the laser source enables,for the first time,high-contrast,fast CRS imaging without complicated noise reduction via balanced detection *** capabilities are demonstrated in this work by imaging a wide range of species such as living human cells and mouse arterial tissues and performing multimodal nonlinear imaging of mouse tail,kidney and brain tissue sections by utilizing second-harmonic generation and twophoton excited fluorescence,which provides multiple optical contrast mechanisms simultaneously and maximizes the gathered information content for biological visualization and medical *** work also establishes a general scenario for remodelling existing lasers into synchronized two-colour lasers and thus promotes a wider popularization and application of CRS imaging technologies.

关键词： scattering tuning fibre