bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Peer Data on Intersections for Decisions about Coordination of Arterial Traffic Signal
Authors: Day Christopher M. , Brennan Thomas M. , Premachandra Hiromal , Sturdevant James R. , Bullock Darcy M.
Published: February 2012

Decisions on whether to coordinate adjacent intersections are currently made by rules of thumb and couple indices that are based on ratios of volume to distance with modeled traffic flows. As high-resolution event data from signalized intersections become more readily available, it becomes possible to analyze actual link vehicle flows to better characterize whether (and when) signal coordination is desirable. This paper proposes and demonstrates a methodology that uses peer data obtained from adjacent intersections to assess opportunities to improve arterial progression if a noncoordinated system is coordinated. The beginning of green from the upstream intersection was combined with vehicle arrival times from a downstream intersection to characterize whether vehicles were likely to arrive in consistent platoons at the downstream signal. The peer data–based methodology was used to investigate the benefits of extending a coordination plan to a system running without coordination during a late-night period. A case study of a fully actuated late-evening timing plan on an arterial identified opportunities for potential benefits from coordination; the implementation of a timing plan for an adjacent time period reduced travel times by approximately 1 min in both directions on the arterial.
Heuristic Approach for Estimating Arterial Signal Phases and Progression Quality from Vehicle Arrival Data
Authors: Barkley Tiffany , Hranac Rob , Fuentes Kim , Law Philip
Published: February 2012

Automated performance-monitoring systems take in intelligent transportation system sensor data in real time, archive them, and analyze them. These systems are needed to help local agencies identify problem areas, develop improvement plans, and perform before and after evaluations on the impacts of traffic management changes. Research performed in the past few years has demonstrated the utility of these systems for local transportation agencies, particularly for evaluating signal progression quality. However, acquiring the critical data items for existing arterial intelligent transportation systems—signal phase event information—is often a practical challenge because the configuration of the existing system of most arterial systems does not record or communicate signal phase events to a central location. As a solution to that problem, this paper documents an approach to estimate signal phase data with in-pavement vehicle sensors, a data source that is generally available from arterial systems. On many arterial systems, these sensors frequently communicate data from the field to a central traffic management center. The goal of this paper was to make recent arterial progression quality research implementable by developing a method to gather signal phase event data in a way that would be practical for most local transportation agencies, given their existing arterial systems. Two proposed methods were tested on a year's worth of data from a 2-mi arterial corridor in Carson, California. Results showed that sensor data from central traffic management centers could be used to develop accurate measurements of signal phase events when coupled with timing plans.
Quantifying the Benefit of Retiming Traffic Signals through Multiple Regression
Authors: Mulandi James , Martin Peter T.
Published: February 2012

One of the most cost-effective measures of improving traffic flow in urbanized areas is retiming traffic signals. However, traffic signal timings are generally not reviewed and updated as often as they should be. As a result, timing patterns do not reflect current traffic and pedestrian needs. This flaw causes a major increase in traffic delay at signalized intersections. A fundamental step in updating signal timings is the estimation of the benefit of retiming, for which signal timings optimization and analysis tools are often used. The purpose of this study was to develop an alternative method for estimating the benefit of retiming signals that would not rely on analytical tools. Different linear and nonlinear regression models were developed. The dependent variable was the benefit, that is, reduction in delay after optimizing signal timings. Fourteen independent variables were derived from the common parameters that affected signal timing performance, such as volumes, capacity, geometry, and current signal timings. Three real actuated, coordinated networks were used. Regression models can be used to estimate the benefit of retiming signals.
Comparison of Alternative Real-Time Performance Measures for Measuring Signal Phase Utilization and Identifying Oversaturation
Authors: Smaglik Edward J. , Bullock Darcy M. , Gettman Douglas , Day Christopher M. , Premachandra Hiromal
Published: February 2012

Various control algorithms process vehicle detector on and off times with the objective of quantifying split performance. Two such metrics are green occupancy ratio (GOR) and volume-to-capacity (v/c) ratio, both of which can be used to estimate the efficiency of a split as well as estimate oversaturated conditions. The GOR metric is attractive because of its simplicity of implementation; the v/c ratio is based on well-established traffic flow concepts and is independent of detector geometry although additional processing is required to develop the metric. Characterizing the impact of detection zone length and vehicle speed on the GOR as well as comparing its performance with another metric is important in understanding the robustness of GOR as a surrogate performance metric. This paper analyzes the difference between calculated GOR and v/c ratios over different detection zone lengths and differing vehicle speeds, compares these values with a calculated delay metric, and observes the effectiveness of GOR as an indicator of oversaturation. On the basis of the analysis, the paper documents the influence of approach speed and detection zone length on the calculated GOR metric. The paper concludes that the GOR values tend to reach a saturated value of 1.0 more rapidly than v/c, making it challenging for the analyst to identify oversaturated conditions by the metric alone. For practitioners using the GOR metric, it is critical that the system be calibrated properly because of the sensitivity of GOR to the detection zone length and vehicle speed. However, because direct measurement of v/c is difficult to obtain, GOR may still be a reasonable surrogate in real-time performance assessment of traffic signal systems.
Evaluating Robustness of Signal Timings for Varying Traffic Flows
Authors: Stevanovic Aleksandar , Kergaye Cameron , Stevanovic Jelka
Published: February 2012

Traffic signal systems are usually retimed on the basis of sampled traffic counts. Yet limited traffic data may not represent typical conditions for optimizing traffic signal systems. When extensive traffic counts are not available, several approaches must be considered: How should signal timings be optimized if multiple counts exist? Should signal timings be based on maximal (or near maximal) traffic counts or should traffic volumes that are more frequently observed in the field be used? This study provides answers to those questions by investigating the performance of signal timing plans developed for various traffic count scenarios, at conditions of varying traffic demand. One key contribution of this study is accurate modeling of varying traffic conditions that were captured from field traffic counts during 155 weekdays in 2009. VISSIM's model of Park City, Utah, calibrated and validated in previous studies, was used to model field traffic conditions and to evaluate the quality of various signal timing plans. Results show that signal timing plans that are based on average traffic flows (mean, mode, and median) perform best (and are most robust) when exposed to day-to-day traffic flow variability. Results also show that although optimizing signal timings for higher traffic demand is suboptimal, this strategy is better than optimizing signals for lower traffic demand and should be used when sufficient traffic data are not available.
New Evidence of Improvements in Dilemma Zone Protection by Detection-Control System
Authors: Middleton Dan , Bonneson James , Charara Hassan
Published: February 2012

This research conducted a field evaluation of the detection-control system (D-CS) at eight sites located in four states. D-CS is similar to a traditional advance detector system in that it uses information from detectors located upstream of the intersection to extend the green. However, it differs from traditional advance detector systems because it monitors individual vehicles on the intersection approach on a lane-by-lane and on a vehicle length basis. It then uses this information to predict the best time to end the major-road through phase. The D-CS software continuously evaluates and updates this prediction in real time. The prediction is based on the number of vehicles currently in, or predicted to soon arrive in, the dilemma zone as well as the number of conflicting phases with a call for service. On the basis of the findings to date, D-CS is successful in improving crash surrogate measures of effectiveness. Findings from a regression analysis for 1-h periods indicated that the “after” study periods experienced 82% fewer red light violations, 73% fewer vehicles in the dilemma zone, and 51% fewer max-outs than the before-study periods. The emphasis of D-CS on trucks is a salient feature that makes it unique in comparison with other methods of dilemma zone protection. The government is urged to encourage and support a group of interested manufacturers in integrating the D-CS algorithm into their controllers.
Estimating Signalized Intersection Delays to Transit Vehicles
Authors: Hellinga Bruce , Yang Fei , Hart-Bishop Jordan
Published: February 2012

Many transit agencies have deployed automatic vehicle location (AVL) systems, automatic passenger counting (APC) systems, or both on a portion of their transit vehicle fleets. Data from these systems are used for realtime system monitoring and control, and archived data are often used for service performance reporting and for service planning. This paper proposes and demonstrates a method by which these archived data can be used to estimate the mean and variance of transit vehicle delays caused by signalized intersections. The proposed method is suitable for application to most transit AVL-APC databases and is demonstrated with data from Grand River Transit, the public transit service provider in the region of Waterloo, Ontario, Canada. The results obtained from the application to field data indicated that the proposed method was able to explain 96% of the variation in observed mean transit vehicle delay at signalized intersections. These results suggest that the proposed method has practical application for the identification and prioritization of candidate measures for transit priority, including transit signal priority (green extension, early green, special transit phases) and queue jump lanes.
Predictive Priority for Light Rail Transit
Authors: Zlatkovic Milan , Martin Peter T. , Stevanovic Aleksandar
Published: February 2012

The goal of this paper is to assess the operational implementation of strategies for predictive light rail priority through microsimulation. A 2-mi corridor in Salt Lake County, Utah, where the University Line of light rail line operates, was studied. The study used VISSIM microsimulation models to analyze light rail operations and the effects that light rail priority has on transit and vehicular traffic. Results showed that although the existing priority strategies had no effects on vehicular traffic along the corridor, they reduced train travel times by 20% to 30%. Left turns along the main corridor were slightly affected by the priority. Although the priority strategies could have minor to major effects on vehicular traffic along side streets through increased delays, they reduced train delays by 2.5 min along the corridor. Enabling priority at the 700 E intersection (where the priority was currently not active) would help reduce delays for trains by an additional 10%, with a small increase in vehicle delays. However, the coordinated north–south through movements would experience minimum impacts. Three recommendations emerged from the study: enable priority at 700 E to improve transit without major effects on vehicular traffic; reset priority parameters at intersections adjacent to light rail stations so that the priority call encompasses station dwell times; and consider removing the queue jump strategies, so as to reduce delays for the corridor through movements and help preserve coordination patterns.
Traffic Signal Optimization with Application of Transit Signal Priority to an Isolated Intersection
Authors: Christofa Eleni , Skabardonis Alexander
Published: February 2012

Transit signal priority (TSP) is a control strategy that has been used extensively to improve transit operations in urban networks. However, several issues related to TSP deployment—including the effect of TSP on auto traffic and the provision of priority to transit vehicles traveling in conflicting directions at traffic signals—have not yet been addressed satisfactorily by existing control systems. This paper presents a real-time, traffic-responsive signal control system for signal priority on conflicting transit routes that also minimizes the negative effects on auto traffic. The proposed system determines the signal settings that minimize the total person delay in the network while assigning priority to the transit vehicles on the basis of their passenger occupancy. The system was tested through simulation at a complex signalized intersection located in Athens, Greece, that had heavy traffic demands and multiple bus lines traveling in conflicting directions. Results showed that the proposed system led to significant reductions in transit users’ delay and the total person delay at the intersection.
Quantifying Dynamic Factors Contributing to Dilemma Zone at High-Speed Signalized Intersections
Authors: Wei Heng , Li Zhixia , Yi Ping , Duemmel Kevin R.
Published: February 2012

The issue of the dynamic yellow light dilemma zone (DZ) has been raised by researchers for many years. However, quantitative study of the inherent factors contributing to the dynamic DZ remains an issue, perhaps because of the lack of effective means for collecting the trajectory data. This paper presents an analysis of the dynamic characteristics of major contributing factors for Type I DZ and the option zone on the basis of vehicle trajectory data during yellow intervals. The qualified trajectory data of 1,445 vehicles were extracted from 46-h high-resolution videos shot at four high-speed signalized intersections in Ohio with the use of the cost-effective software VEVID, developed and upgraded by the first two authors. The statistical analysis of the obtained trajectory data quantitatively revealed the dynamic nature of major DZ contributing factors. Results indicated that the minimum perception–reaction time of drivers was greatly influenced by speed and could be modeled as a function of the speed. The maximum deceleration rate for stopping and the maximum acceleration rate for running a yellow light were greatly dependent on speed and the 85th percentile speed of the intersection approach. The rates could be expressed as a function of those two variables. On the basis of the new findings, the traditional Type I DZ model was greatly modified and improved. The new model provides a theoretical base for updating the existing DZ tables with the identified dynamic characteristics of the contributing factors.
Automated Intersection Control
Authors: Fajardo David , Au Tsz-Chiu , Waller S. Travis , Stone Peter , Yang David
Published: February 2012

Congestion is one of the biggest challenges faced by the transportation community; congestion accounted for an estimated $87.2 billion in losses in 2007 alone. Transportation professionals need to go beyond capacity expansion projects and explore novel strategies to mitigate traffic congestion. Automated intersection management is a novel strategy that has the potential to greatly reduce intersection delay and improve safety. Although the implementation of such a system is contingent on the development of automated vehicles, competitions such as the Grand Challenge and Urban Challenge of the Defense Advanced Research Projects Agency have shown that this technology is feasible and will be available. Therefore, the development of the infrastructure and associated control methods required to exploit fully the benefits of such technology at the system level is critical. This research explores one such innovative strategy, an automated intersection control protocol based on a first-come, first-served (FCFS) reservation system. The FCFS reservation system was shown to reduce intersection delay significantly by exploiting the features of autonomous vehicles. Microscopic simulation experimental results showed that the FCFS reservation system significantly outperformed a traditional traffic signal in reducing delay.
Detection Performance of Wireless Magnetometers at Signalized Intersection and Railroad Grade Crossing under various Weather Conditions
Authors: Medina Juan C. , Hajbabaie Ali , Benekohal Rahim (Ray) F.
Published: February 2012

The performance of wireless magnetometers for vehicle detection was evaluated under favorable and adverse weather conditions at two sites: (a) a signalized intersection with stop bar and advance detection zones and (b) a railroad grade crossing, as a potential backup system to control the operation of gates. Loop detectors and magnetometers were installed at the same locations, providing similar detection areas. Discrepancies between activations from loops and magnetometers provided pointers to potential errors in the systems, and video images were used to verify them visually. At the signalized intersection, the most common type of detection error by the magnetometers in the stop bar zones was a false call caused by vehicles in the adjacent lane, with 5.6% to 7.6% error per lane in favorable weather and 7.7% to 15.4% in winter conditions. At the advance zones the most frequent error in all weather conditions was a missed call caused by vehicles traveling between two lanes, ranging from 2.9% to 9.7% in the left-turn lanes. At the railroad grade crossing, however, most errors were false and stuck-on calls. On average, there was one stuck-on call per every 150 trains, and one per every 2,800 vehicles. False calls varied from 13.4% to 14.1% in the through lane and from 55.9% to 59.9% in the left-turn lane, caused mostly by vehicles traveling in the opposing direction (this was an atypical location with no median separating the two directions of traffic).
Computing Individual Path Marginal Cost in Networks with Queue Spillbacks
Authors: Qian Zhen (Sean) , Zhang H. Michael
Published: February 2012

“Individual path marginal cost” (IPMC) is defined as the change in travel cost of one unit of flow on a time-dependent path caused by one unit of flow on another time-dependent path. Knowledge of IPMC is central to dynamic transportation modeling, for instance, to compute system-optimal network performance, to solve a dynamic origin–destination (O-D) estimation problem, and to analyze equity issues for travelers with different origins and destinations. This paper proposes a method of approximating IPMC for general networks, in which a cell transmission model–based kinematic wave model is used to model traffic dynamics. By tracing the changes in the cumulative flow curves of the bottleneck links on which queues form during dynamic network loading, an approximation method is developed to obtain the IPMC for the cases of merge junctions, diverge junctions, and general junctions. This method was applied to compute the total path marginal cost in a network. The results showed that vehicles at the beginning of the congestion duration had significantly larger marginal travel costs than other vehicles. The method was then applied to solve a dynamic O-D estimation problem with partial link-flow counts and historical O-D trip tables. With the incorporation of IPMC into the estimation procedure, both the O-D demands and the observed path travel times were successfully reproduced.
Efficient Methodology for Benchmarking Dynamic Origin–Destination Demand Estimation Methods
Authors: Djukic Tamara , Van Lint J. W. C. , Hoogendoorn S. P.
Published: February 2012

One of the key traffic variables required for the ex post and ex ante evaluation of traffic management and policy measures is origin–destination (O-D) demand matrices. Without ground truth O-D information, however, it is difficult, if not impossible, to assess the quality of an O-D estimation method because so many unknowns are involved. One indicator of the quality of an O-D estimation method is the sensitivity of the method to, and its robustness against, random and structural perturbations of the input from a few typical test networks (e.g., data from sensors, prior O-D matrices). In this paper, an assessment methodology is proposed on the basis of the Latin hypercube method, which is an efficient alternative to Monte Carlo sampling and particularly suited for high-dimensional estimation problems. The methodology is demonstrated on a real urban corridor network for a well-known O-D estimation method (the minimum information estimation method) to illustrate the results that can be obtained and how these results can be used to benchmark different O-D estimation methods.
Time-Dependent Origin–Destination Demand Estimation
Authors: Verbas I. Ömer , Mahmassani Hani S. , Zhang Kuilin
Published: February 2012

This paper proposes a modified bi-level optimization algorithm to estimate the time-dependent origin–destination trip matrices for large-scale networks with multiple vehicle classes. Methodologies are presented to overcome the challenges caused by the scale of the problem. The upper-level problem, a bound-constrained quadratic problem, had many variables and parameters for a network with around 68,000 links, 28,000 nodes, and 3,700 zones. Techniques to reduce the number of variables and parameters are described in this study, along with an approach to reduce the time and memory requirement of the lower-level problem. Furthermore, the basic approach, which had been applied only to a single vehicle class, was extended and adapted in this study to estimate matrices for single-occupancy and high-occupancy vehicles jointly. Two solution packages, MINOS and KNITRO, were tested for the upper-level problem. The solution package KNITRO was run with an option to use an interior point–conjugate gradient algorithm, which was well suited to large-scale nonlinear problems. The modified bi-level algorithm was applied to estimate the time-dependent demand patterns for the New York City regional network.
Day-to-Day Dynamic Model in Discrete–Continuum Transportation Networks
Authors: Guo Xiaolei , Liu Henry X.
Published: February 2012

In a discrete–continuum transportation network, the freeway network is modeled as an ordinary discrete link–node network; the dense minor streets are approximated as a two-dimensional continuum; and the two are connected at a limited number of points (freeway ramps). This representation of a discrete–continuum network highlights the backbone role played by the freeway network in modern urban transportation systems, and the continuum approximation approach suits large-scale dense minor streets. Previous studies on continuum network modeling all focused on the concept of network equilibrium. In this paper, the disequilibrium flow evolution process is studied after some network disruption or facility change has taken place. A day-to-day dynamic model suitable for the discrete–continuum representation of urban transportation networks is proposed. This model captures travelers' cost-minimization behavior in their path finding and also captures their inertia. The fixed point of the proposed dynamical system is the classic Wardrop user equilibrium. A numerical example is provided to demonstrate the effectiveness of the model.
Application of Discrete Fourier Transform to Find Reliable Shortest Paths
Authors: Wu Xing , Nie Yu (Marco)
Published: February 2012

Reliable shortest paths, in this paper, are paths that ensure a desired probability of arriving on time or earlier with the least time budget. Finding reliable shortest paths requires the evaluation of path travel time distributions through numerical convolution, which is a computationally intensive procedure. This paper develops several convolution methods based on the discrete Fourier transform (DFT) and compares them with a direct convolution method implemented with adaptive discretization. Two shortcomings in the conventional DFT-based convolution are recognized, namely, the incompatibility with dynamic programming and the computational inefficiency associated with support points that have negligible probability mass. Remedies are proposed to overcome these shortcomings. However, numerical experiments suggest that, even with these improvements, the DFT-based convolution methods are still not as computationally competitive as the direct convolution method, contrary to the promise of the theoretical complexity analysis.
Transit Stop-Level Origin–Destination Estimation through Use of Transit Schedule and Automated Data Collection System
Authors: Nassir Neema , Khani Alireza , Lee Sang Gu , Noh Hyunsoo , Hickman Mark
Published: February 2012

As fare and data collection technology has developed, the resolution of collected data has reached the level of the individual traveler in investigations of transit passenger behavior. This paper investigates the use of these data to estimate passenger origins and destinations at the level of individual stops. Because of a lack of information from the fare collection system, researchers still need some estimate of passengers' alighting stops to complete each passenger trip chain on a specific day. Automated fare collection (AFC) and automated vehicle location (AVL) systems are the inputs to the estimation. Instead of typical AVL data, the paper proposes two models to estimate the alighting stop; both consider passenger trip chaining by using AFC data, transit schedule data (Google's General Transit Feed Specification), and automated passenger counter (APC) data. The paper validates the model by comparing the output to APC data with vehicle location data (APC-VL) and performs sensitivity analyses on several parameters in the models. To detect transfer trips, the new models propose a submodel that takes into account the effect of service headway in addition to some typical transfer time thresholds. Another contribution of this study is the relative relaxation of the search in finding the boarding stops, which enables the alternative algorithm to detect and fix possible errors in identification of the boarding stop for a transaction. As a result, the paper provides algorithms for the proposed models and sensitivity analysis for several predefined scenarios. The results are based on data and observed bus passenger behavior in the Minneapolis–Saint Paul, Minnesota, area.
Bi-Level Optimization Model for Public Transportation Network Redesign Problem
Authors: Fan Wei (David) , Machemehl Randy B.
Published: February 2012

Spatial equity is an extremely important issue in both design of a new and redesign of an existing transit (and highway) network because it is concerned with the benefit distribution among transit (and highway) network users. This paper presents a bi-level optimization model—in which the spatial equity issue is explicitly considered for the first time—for solving the public transportation network redesign problem (PTNRP). The goal of the upper-level subprogram is to minimize total cost, including user cost, operator cost, and unsatisfied demand cost, for the studied bus transit network, subject to a variety of resource- and policy-related constraints. The lower-level subprogram is a user self-routing optimization problem in which all transit users try to find the transit route to minimize their own travel cost (or time) and number of transfers in the network. Then, a procedure for a genetic algorithm–based solution is developed to solve this PTNRP bi-level optimization model. Network experiments are conducted, and numerical results are described. Future research directions are also given.
Vulnerability Analysis of Transportation Network under Scenarios of Sea Level Rise
Authors: Lu Qing-Chang , Peng Zhong-Ren
Published: February 2012

Climate change is attracting increasing attention from transportation planners, engineers, and decision makers. As a result of climate change, sea level rise is rapidly becoming a major concern, especially for coastal regions. This paper develops an accessibility-based process to analyze transportation network vulnerability to quantify networkwide vulnerability and to identify the most vulnerable regions under different scenarios of sea level rise. The accessibility reduction rate before and after inundation is calculated to measure the potential consequences. The probability of different sea level rise scenarios—together with the overall accessibility reduction—contributes to the overall vulnerability of the transportation network. Most notably, the traffic analysis zones with the most accessibility reduction are considered the most vulnerable areas. This methodology is applied to the south Miami, Florida, road network under two sea level rise scenarios for 2060. The authors estimated the extent of road network vulnerability and accessibility reduction of individual traffic analysis zones for the two scenarios. The results show an almost 100% accessibility reduction for traffic analysis zones with all roads inundated and as high as 30% accessibility reduction in zones with some or no roads directly affected. This information can help local transportation planners, engineers, and decision makers identify the most vulnerable areas and transportation facilities resulting from sea level rise so as to make better and more informed decisions about adaptation planning and retrofitting.
Enhancing the Quality of Infrared-Based Automatic Pedestrian Sensor Data by Nonparametric Statistical Method
Authors: Yang Hong , Ozbay Kaan , Bartin Bekir
Published: February 2012

With the advent of intelligent transportation systems in the past several decades, sensors are being extensively used to detect and count vehicle movements. The use of similar sensing technologies to detect pedestrian movements, however, is relatively new. Pedestrian counts are essential for decision making in pedestrian facility planning, signal timing, and pedestrian safety modeling. Conventional methods such as manual counting and videotaping can hardly satisfy the requirements of programs for the long-term collection of pedestrian data. Advances in sensing technologies have increased the ability to automate pedestrian data collection with the use of infrared sensors. However, the quality of the data from infrared sensors is still a problem; several field studies have shown that these types of sensors do not always perform perfectly. Field tests conducted in this study and by other research teams showed that infrared sensors usually counted significantly fewer pedestrians than the actual number. Thus, the quality of the data from infrared sensors needs to be enhanced. This paper proposes a nonparametric statistical method to calibrate raw sensor data to achieve this goal. A bivariate bootstrap sampling procedure was used to obtain correction factors for new counts instead of the traditional regression-based approach. Two case studies were used to test the validation of the proposed calibration procedure. Test results showed that the proposed procedure could improve the quality of the sensor data by reducing the discrepancy between sensor counts and ground truth (true) data. The transferability of the calibration procedure was also verified through the case studies.
Modeling of Pedestrian Activity at Signalized Intersections: Land Use, Urban Form, Weather, and Spatiotemporal Patterns
Authors: Miranda-Moreno Luis F. , Fernandes David
Published: February 2012

The present study evaluated the effects of land use, urban form patterns, and weather conditions on pedestrian activities. In this research, 8 h of daily manual pedestrian counts during the a.m. peak, noon, and p.m. peak periods were collected from a large sample of signalized intersections throughout Canada. The use of different model settings was attempted as part of a model sensitivity analysis. Results revealed that a 100% increase in population density or the amount of commercial space around intersections increased pedestrian flows by 22.7% to 37.1% and 10.7% to 11.7%, respectively. Moreover, the pedestrian activity at an intersection decreased as the distance from downtown increased (with an elasticity of 44%). Also, very warm weather (with temperatures >30°C) decreased pedestrian activity by up to 22%. This study was the first attempt to develop a spatiotemporal model of pedestrian activity in a large city. These results should be taken with caution, however, because the sample of intersections was not randomly selected. Moreover, the modeling techniques used in this research did not take into account the potential spatial correlation across intersections. This factor may have caused bias in parameter estimates. These issues are part of future work.
A decade of change in the hydraulic connection between an Antarctic epishelf lake and the ocean
Authors: Galton-Fenzi Ben K. , Hunter John R. , Coleman Richard , Young Neal
Published: February 2012

Observations of the water level in Beaver Lake, an epishelf lake in East Antarctica, show a regular tidal signal that is lagged and attenuated from the tides beneath the adjacent Amery Ice Shelf. The phase lag and amplitude attenuation can be created by a narrow inlet connection between Beaver Lake and the cavity beneath the Amery Ice Shelf. A forced linear damped oscillator is used to determine the inlet dimensions that are required to produce the observed phase lag and amplitude attenuation. The model shows that the observations are consistent with a tidal flow that is restricted by the drag created by flow in the narrow inlet. Analysis shows that the phase lag and amplitude attenuation of the tides in Beaver Lake has increased over the years 1991-2002, probably due to a thickening of the overlying ice shelf. The response is sensitive to subtle variations in the dimensions of the inlet.
Quality of Categorized Service and Customer Satisfaction in Banking Industry: An Empirical Study on Private Commercial Banks in Bangladesh
Authors: Masukujjaman Md , Akter Afia
Published: February 2012

The main objectives of the study are to evaluate the customer satisfaction of the service quality and to assess whether bank services provided by the institutions are satisfactory to Bangladeshi customers especially in term of service categories like general banking, credit banking and foreign exchange banking services. The study also examines empirically the determinants of service quality in Bangladesh. A questionnaire for such purpose was designed and different statistical methods were applied to analyse the collected data. From the study it is found that the overall service quality in private commercial bank in Bangladesh is moderate, where service quality in general banking services is better than the credit banking services and foreign exchange services though its quality is not too bad . In addition, top ranked banks have high service quality in all categories of services and the lower raked banks are struggling seriously with credit and foreign exchange services. So, as policy recommendation, the banks especially the lower ranked banks should give more emphasis on both the credit and foreign exchange banking services.Key Words: Categorized Service; Perceived Service Quality; Customer Satisfaction.DOI: http://dx.doi.org/10.3329/jbt.v5i2.9933Journal of Business and Technology (Dhaka) Vol. 5(2), July-December, 2010 19-37
Socio-Economic Conditions of Female Garment Workers in Chittagong Metropolitan Area  An Empirical Study
Authors: Chowdhury Nazneen Jahan , Ullah Md Hafu
Published: February 2012

This paper is an endeavor to depict the conditions of the female workers from two perspectives. One is social perspective and the other is economic perspective. The analysis is based on the survey of 151 female workers of 29 garment industrial units located in different parts of Chittagong Metropolitan area. This study suggests that the standard of living of the female garment workers is still in precarious condition and they are not free from the vicious circle of poverty and face extreme difficulties in obtaining their basic needs for survival even. This paper recommends measures for improving the prevailing socio-economic facilities, to a great extent, to achieve female workers’ satisfaction at the maximum level. Key Words: Female Garments Workers; Social Factors; Economic Factors.DOI: http://dx.doi.org/10.3329/jbt.v5i2.9935  Journal of Technology (Dhaka) Vol. 5(2), July-December, 2010 53-70
Compliance Practices in Garment Industries in Dhaka City
Authors: Rahman Md Arifur , Hossain Mir Sohrab
Published: February 2012

The readymade garment RMG industry in Bangladesh has experienced an unprecedented growth .over the last three decades and become a fast growing industry in Bangladesh. This industry plays a vital role in the economy in terms of export earnings, employment generation ,poverty alleviation and empowering the woman. For development of this sector, Bangladesh needs to emphasize on the factory working environment, social issues, labor relations and compliances with codes of conduct. This paper is based on descriptive and inferential research. The paper suggests the improvement of factory activities through compliances and finds out a close relationship between compliance and productivity.DOI: http://dx.doi.org/10.3329/jbt.v5i2.9936  Journal of Technology (Dhaka) Vol. 5(2), July-December, 2010 71-87
Employee Participation in Decision Making in RMG sector of Bangladesh: Correlation with Motivation and Performance
Authors: Bhuiyan Md Anowar Hossain
Published: February 2012

Participation in decision making in industry results in satisfaction of employees and an increase in productivity and profit. It empowers the employer to achieve the organizational goal. This study was conducted to assess the present situation, nature and types of workers participation and motivation system in Ready Made Garments (RMG) sector of Bangladesh. The study identifies the causes of poor participation of the employees in decision making and correlate between employee participation, motivation and performance. The study revealed that there is a significant positive correlation between decision making, motivation and performance. The study also identified five major causes of poor participation in decision making, such as, absence of willingness of the management, absence of labor union activities, lack of workforce diversity, illiteracy of the workers and political grouping among the workers.DOI: http://dx.doi.org/10.3329/jbt.v5i2.9984Journal of Technology (Dhaka) Vol. 5(2), July-December, 2010 122-132
Making TeleTalk a Healthy Competitor among the Mobile Phone Operators in Bangladesh
Authors: Rahman Md Tahdur
Published: February 2012

The people of Bangladesh are now dreaming of a digital Bangladesh. Fast development of telecommunications network is a must for the realization of the vision and aspiration of digital Bangladesh. Teletalk is the smallest in the six operator mobile phone market in Bangladesh having only 1.07 million subscribers and 2.04% market share. The present Teletalk is far away from its objectives, mission, and vision. Therefore, the main objective of this study is to analyse Teletalk and offer some suggestions to make it a healthy competitor among the mobile phone operators. The main strength of Teletalk is its domestic base and government ownership that encourages patriotic people to use TeleTalk. But bad network is its main weakness, and GP, Banglalink and Warid are the threats for Teletalk because of their size and quality of service. In order to become competitive in such a situation Teletalk should advertise its native nature more and apply direct selling policy along with strengthening the network coverage.DOI: http://dx.doi.org/10.3329/jbt.v5i2.9985Journal of Technology (Dhaka) Vol. 5(2), July-December, 2010 133-149
Anthropogenic Climate Change and Allergic Diseases
Authors: Blando James , Bielory Leonard , Nguyen-Feng Viann N. , Diaz Rafael , Jeng Hueiwang Anna
Published: February 2012

Climate change is expected to have an impact on various aspects of health, including mucosal areas involved in allergic inflammatory disorders that include asthma, allergic rhinitis, allergic conjunctivitis and anaphylaxis. The evidence that links climate change to the exacerbation and the development of allergic disease is increasing and appears to be linked to changes in pollen seasons (duration, onset and intensity) and changes in allergen content of plants and their pollen as it relates to increased sensitization, allergenicity and exacerbations of allergic airway disease. This has significant implications for air quality and for the global food supply.
Increased Activity of Cell Surface Peptidases in HeLa Cells Undergoing UV-Induced Apoptosis Is Not Mediated by Caspase 3
Authors: Piva Terrence J. , Davern Catherine M. , Hall Paula M. , Winterford Clay M. , Ellem Kay A. O.
Published: February 2012

We have previously shown that in HeLa cells treated with a variety of agents there is an increase in cell surface peptidase (CSP) activity in those cells undergoing apoptosis. The increase in CSP activity observed in UVB-irradiated cells undergoing apoptosis was unaffected when the cultures were treated with the aminopeptidase inhibitor bestatin, and matrix metalloprotease inhibitor BB3103, but greatly enhanced when treated with the caspase 3 inhibitor-DEVD, and reduced in the presence of the poly(ADP-ribose) polymerase (PARP) inhibitor-3-aminobenzamide (3AB). Neither 3AB nor DEVD had an effect on the gross morphology of the apoptotic cells observed under electron microscopy, nor did they have an effect on phosphatidylserine eversion on the cell membrane, or that of PARP cleavage. All the agents except for DEVD had no effect on the level of caspase 3 activity in the cells. The results suggest that other caspases may cleave PARP in these cells. Both 3AB and DEVD treatment reduced the level of actin cleavage seen in the apoptotic cells. The increase in CSP activity observed in cells undergoing UVB-induced apoptosis appears to involve PARP but not caspase 3.
Synthesis, Characterization, X-ray Crystallography, Acetyl Cholinesterase Inhibition and Antioxidant Activities of Some Novel Ketone Derivatives of Gallic Hydrazide-Derived Schiff Bases
Authors: Gwaram Nura Suleiman , Ali Hapipah Mohd , Abdulla Mahmood Ameen , Buckle Michael J. C. , Sukumaran Sri Devi , Chung Lip Yong , Othman Rozana , Alhadi Abeer A. , Yehye Wageeh A. , Hadi A. Hamid A. , Hassandarvish Pouya , Khaledi Hamid , Abdelwahab Siddig Ibrahim
Published: February 2012

Alzheimer’s disease (AD) is the most common form of dementia among older people and the pathogenesis of this disease is associated with oxidative stress. Acetylcholinesterase inhibitors with antioxidant activities are considered potential treatments for AD. Some novel ketone derivatives of gallic hydrazide-derived Schiff bases were synthesized and examined for their antioxidant activities and in vitro and in silico acetyl cholinesterase inhibition. The compounds were characterized using spectroscopy and X-ray crystallography. The ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays revealed that all the compounds have strong antioxidant activities. N-(1-(5-bromo-2-hydroxyphenyl)-ethylidene)-3,4,5-trihydroxybenzohydrazide (2) was the most potent inhibitor of human acetyl cholinesterase, giving an inhibition rate of 77% at 100 μM. Molecular docking simulation of the ligand-enzyme complex suggested that the ligand may be positioned in the enzyme’s active-site gorge, interacting with residues in the peripheral anionic subsite (PAS) and acyl binding pocket (ABP). The current work warrants further preclinical studies to assess the potential for these novel compounds for the treatment of AD.
Intelligent Control of a Sensor-Actuator System via Kernelized Least-Squares Policy Iteration
Authors: Liu Bo , Chen Sanfeng , Li Shuai , Liang Yongsheng
Published: February 2012

In this paper a new framework, called Compressive Kernelized Reinforcement Learning (CKRL), for computing near-optimal policies in sequential decision making with uncertainty is proposed via incorporating the non-adaptive data-independent Random Projections and nonparametric Kernelized Least-squares Policy Iteration (KLSPI). Random Projections are a fast, non-adaptive dimensionality reduction framework in which high-dimensionality data is projected onto a random lower-dimension subspace via spherically random rotation and coordination sampling. KLSPI introduce kernel trick into the LSPI framework for Reinforcement Learning, often achieving faster convergence and providing automatic feature selection via various kernel sparsification approaches. In this approach, policies are computed in a low-dimensional subspace generated by projecting the high-dimensional features onto a set of random basis. We first show how Random Projections constitute an efficient sparsification technique and how our method often converges faster than regular LSPI, while at lower computational costs. Theoretical foundation underlying this approach is a fast approximation of Singular Value Decomposition (SVD). Finally, simulation results are exhibited on benchmark MDP domains, which confirm gains both in computation time and in performance in large feature spaces.
LOLS Research in Technology for the Development and Application of New Fiber-Based Sensors
Authors: Coelho João , Nespereira Marta , Silva Catarina , Rebordão José
Published: February 2012

This paper presents the research made at the Laboratory of Optics, Lasers and Systems (LOLS) of the Faculty of Sciences of University of Lisbon, Portugal, in the field of fiber-based sensors. Three areas are considered: sensor encapsulation for natural aqueous environments, refractive index modulation and laser micropatterning. We present the main conclusions on the issues and parameters to take in consideration for the encapsulation process and results of its design and application. Mid-infrared laser radiation was applied to produce long period fiber gratings and nanosecond pulses of near-infrared Q-switch laser were used for micropatterning.
Lampes d'Algérie II. Lampes grecques, hellénistiques et tardo-républicaines
Authors: Bussière Jean
Published: February 2012

Cette étude s'inscrit dans le cadre d'un travail d'ensemble sur le luminaire antique découvert en Algérie (cf Ant. afr, 25, 26 et 28).

Le recensement qui porte sur un nombre appréciable d'exemplaires et concerne une vaste aire géographique fait ressortir l'importance relative d'une production, celle du type Deneauve X, qui s'affirme comme étant bien nord africaine.

Par ailleurs, si les conditions de découverte n'apportent que peu de précisions d'ordre chronologique, cette carence est compensée par l'abondance d'exemplaires restés pour la plupart inédits : plus d'une trentaine pour chacun des principaux types tardo-républicains.

En outre, quelques spécimens de la forme Dressel 3, dont une partie de moule, attestent l'existence, dès l'époque républicaine, d'un début de fabrication locale contrairement à l'opinion longtemps admise d'un monopole des exportations de lampes d'Italie vers les Provinces.