Minor Stream Research Articles

Control logic algorithm to create gaps for mixed traffic: A comprehensive evaluation

Abstract Over the last decade, the increase in the number of vehicles has affected traffic performance, causing traffic congestion. However, intersections, where different flows intersect, are among the primary causes of traffic congestion besides bottlenecks. Bottlenecking in the minor stream is mainly due to the extended queueing, specifically due to minimal gaps in the mainline stream as the intersection’s high priority exists with the major stream. This research aims to control connected and automated vehicles (CAVs) to help generate additional usable gaps for the minor road vehicles to enter the intersection without interrupting the mainline traffic flow. A probability function is developed to estimate the probability of CAVs creating additional usable gaps. The proposed logic is simulated in unsignalized and semi-actuated signalized intersections, and a field investigation is conducted. Simulation results show that the minor road delays and queue length are minimized without causing a significant delay to the mainline. Results show that major road interruptions are reduced at a semi-actuated signal control scenario when CAVs’ penetration increases. It can be observed that deploying CAVs in the road network with the proposed method can positively impact traffic efficiency, where the intersection’s performance and safety are improved.

Analiz izmeneniya koeffitsienta sherokhovatosti rusla maloi reki v zadannom stvore (na primere r. Chernoi) [Roughness coefficient meas-urements of the Chernaya River channel

The paper presents the determination of the roughness coefficient of the minor river channel, since one of the main design parameters depends on the minor stream, required for a substantiation of design decisions. In accordance with the regulatory documents of the Russian Federation, the roughness coefficient is taken according to the visual characteristics of the riverbed.The purpose of this work is to determine the relationship of the roughness coefficient and dimensionless complexes at different water depths (before and after entering the floodplain).All calculations are performed according to the results of studying the hydrological conditions of the Chernaya river. The roughness coefficient is determined by the numerical method.Analysis of the maximum depth allows to obtain its certain value. It is shown that the hydraulic radius increases at a higher depth. When the maximum depth is deeper, this dependence is nonmonotonic, and when water enters the floodplain, the hydraulic radius strongly differs from the average depth of the minor stream. It is found that before entering the floodplain, there is a significant stochastic relationship between the roughness coefficient, Reynolds number and the dimensionless complex. After entering the floodplain, there is a close stochastic relationship between roughness coefficient and the Froude number. When determining the minimum water levels, the exponent of Chezy's velocity factor in the Manning formula cannot be considered a constant value, because this can lead to a great error.

Pilgrims, Protest Tourists, and Palestinians: Abu Dis, Bethlehem, Dheisheh Camp

The central idea of this essay is that nonindigenous vernacular image-making by protest tourists on the Palestinian side of the Israeli separation barrier and elsewhere holds little meaning for the permanent residents beyond a relatively minor revenue stream. Prior to making this argument, I provide a short historical background about the use of vernacular messages in the occupied Palestinian territory known as the West Bank. I then focus on images of martyrs or shaheed and then on separation barrier images by protest tourists mostly in Bethlehem. The final sections are about two artists from the Dheisheh Palestinian Refugee Camp and the images they create within the camp. A coda of sorts discusses a mural within the camp that is venerated by the residents as opposed to the overpainting and defacement that takes place on the separation barrier. Within this final section and elsewhere within this essay, the meaning of sumood is explicated. As a note, protest tourists are defined here not as anti-tourism protesters but rather as tourists whose intent is protest Israeli policies regarding Palestinians.

Gap Acceptance for Yangon Urban and Suburban Intersections

Gap acceptance plays an important role in intersection design and signal warrant. This study investigates gap acceptance of drivers in Yangon, Myanmar. Three T-intersections were selected for study sites; two intersections in the urban area and the other one in Yangon suburb. As Yangon drivers drove on the right-hand side, the key movements that defined the intersection capacity would include left-turn from the major stream (LT-major), right-turn from the minor stream (RT-minor), and left-turn from the minor stream (LT-minor). Raff’s method was applied to determine the gap acceptance for these three conflicting movements. The result showed that the gap acceptance for LT-minor was the longest ranging between 7 to 15 seconds. The shortest gap acceptance belonged to the RT-minor for 4 to 8 seconds. The gap acceptance at urban sites was also shorter than that of suburban in all three movements. The drivers tended to decrease their gap acceptance when the traffic volume increased. However, the relationship between the gap acceptance and traffic flow was not significant.

Analyzing variations in spatial critical gaps at two-way stop controlled intersections using parametric and non-parametric techniques

At two-way stop controlled (TWSC) intersections drivers on minor stream are generally at risk because of the difficulty in judging safe gap between major stream vehicles. Any misjudgment by the driver while choosing gap may result in a collision with major stream vehicle. This paper provides important insights for determining and analyzing spatial critical gaps of drivers at high speed and medium speed TWSC intersections. The critical gap line (CGL) fitted for the accepted and rejected gaps using parametric (binary logit model-BLM) and non-parametric (support vector machines-SVM) techniques gives critical gap values at 15th, 50th and 85th percentile speeds. The evaluation of spatial critical gap with respect to major road vehicle (conflicting vehicle) speed makes it easier to understand the impact of variation in speed on spatial gaps accepted by the drivers on the minor road. The logit models developed revealed that the probability of accepting gap decreases with increase in the speed of the conflicting vehicle and it increases with increase in the distance of conflicting vehicle. The spatial critical gaps estimated using support vector machines were found in close approximation with those estimated using binary logit model. The study results showed that SVMs have very good potential to be an alternative tool for the estimation of driver's critical gap. The spatial critical gaps corresponding to 15th, 50th and 85th percentile speeds for medium speed intersections were 32 m, 38 m and 46 m respectively and for high speed intersections these values were 64 m, 76 m and 104 m respectively. The increase in the magnitude of gap value with respect to the percentile speed clearly states the effect of speed on spatial gaps. The insights from the study can be used to suggest various measures to improve the safety of crossing drivers at uncontrolled intersections. • The study provides important insights for analyzing spatial critical gaps at high speed and medium speed uncontrolled intersections. • BLM and SVM are used as a linear classifiers to fit decision boundary between accepted and rejected gaps. • The spatial critical gaps estimated using BLM and SVM corresponding to 85th percentile speed are 46 m and 45 m respectively. • SVMs have very good potential to be an alternative tool for the estimation of driver's critical gap.

Estimation of critical gap at small roundabout

The gap acceptance theory is basically implied to describe the driver’s behavior in the minor stream at the entry of roundabout searching for a suitable gap at the major stream to merge. The critical gap is an important parameter in the gap acceptance theory. However, the critical gap cannot be measured directly on the field. One way to measure the critical gap is by measuring only the rejected and accepted gaps. This study attempts to determine the critical gap at small roundabout using three different methods namely Raff’s Method, Wu’s Method, and Simple Logit Method. The data is collected at a two-lane roundabout in Skudai – Johor Bahru at the morning and afternoon peak hour using video camera technology. Accepted and rejected gaps are then extracted from the recorded videotape. The accepted and rejected gaps obtained are analysed to determine the critical gap. The findings from the study reveal that the critical gap values from the three methods are almost similar, having a critical gap of 3.45s, 3.60s and 3.45s for Raff’s Method, Wu’s Method, and Simple Logit Method respectively.

Multi Vehicle-Type Right Turning Gap-Acceptance and Capacity Analysis at Uncontrolled Urban Intersections

Intersections are the critical zones where conflicting, merging and diverging movements influence the intersection capacity. Uncontrolled intersections in particular pose dangerous situations to vehicular traffic. During peak vehicular flow, the unpredictable crossing behavior of minor stream vehicles induces delay and reduces the capacity of the intersection. Capacity at uncontrolled intersections is typically measured either by gap acceptance method, empirical regression approaches and conflict technique. Gap acceptance is an important characteristic for analyzing uncontrolled intersections. The behavior of different vehicle types and gap of subject vehicle type from minor street taking right turn to merge with major traffic stream is analyzed using gap acceptance method. The objective of the current study is to analyze the effect of major stream vehicle type combinations on the minor stream vehicle gap-acceptance behavior and to determine the capacity of the minor stream taking into account the influence of the right turning vehicles. The capacity of minor stream calculated using Highway Capacity Manual (HCM) 2010, Luttenin’s model, and Tanner’s model are compared. It is observed that two wheelers are more aggressive than three wheelers for most of the major stream vehicular combinations observed in this study.

Estimation of critical gap of U-turns at uncontrolled median openings

The estimation of critical gap is an important traffic parameter and this is useful to estimate the capacity of U-turning vehicles at uncontrolled median openings. In this study critical gap is estimated by four different methods by collecting data at seven median openings in India. During field study it was observed that, the heterogeneous traffic in India operates very peculiarly and the rule of priority is often violated and aggressive behavior of the minor stream vehicles compels the major stream vehicles to slow down to provide sufficient gap for the U-turn maneuver. These peculiar characteristics warrant for a re-look into the methodology of critical gap estimation. An unconventional method of critical gap estimation using the merging time of the U-turning vehicle is proposed. The merging time to clear the conflict area at uncontrolled median opening was calculated from field data and this time is utilized to estimate the critical gap for different categories of vehicle.

Assessing flood inundation extent and landscape vulnerability to flood using geospatial technology: A study of Malda district of West Bengal, India

Assessment of flood risk zonation and landscape vulnerability to flood are fundamental aspects in flood risk management. Landsat 8 Operational Land Imager (OLI) and ASTER DEM data were used to assess landscape vulnerability to flood inundation and flood risk in Malda district of West Bengal state, India. Flood inundation map was prepared on the basis of water and non-water pixels on images (before and during the flood event). Flood risk map was prepared using equal interval of separation based on elevation and inundated flooded area. Flood inundation map was overlaid on the pre-monsoon land use/land cover map to produce landscape vulnerability to flood. The results revealed that 19% area of the district was flooded during monsoon flood event in 2014 and the agricultural area was most affected land use, sharing 62% of the total flood affected area, followed by river bed (21%), built up (7%) and vegetation (5%). The flood risk map of the district shows that temporary river islands, sand banks along the Ganga river course lie in low flood plain and were considered under high risk zone. The flood plain alongside minor stream drainage in southern, north-western and in between them comes under medium flood risk zones. Flood risk is low in areas which are away from the rivers. Non flooded areas were identified in high lands of eastern region of the district. Landscape vulnerability map shows that the blocks located along the Ganga river namely Kaliachak I, Kaliachak II, Kaliachak III, Manikchak, Ratua I were highly vulnerable to flood. The study suggests that efforts should be made to remove the sediments for increasing the depth of river. Spurs and bed bars should be constructed to avoid great loss of prime agricultural land, property and lives of people.

Nutrient Composition in Litter Fall in Northern Louisiana Hardwood Deciduous Forests

Minor stream bottoms (alluvial floodplains) in the southeastern United States contain large areas of hardwood forests which are a potential sink for upstream nutrients. As a sink, they serve an important role in reducing the loss of nutrients from the sites via the watershed. However, little is known about nutrients stored in forest litter that have the potential to be cycled back to the forest or lost through removal from the site. Three hardwood stands of varying management regimens that span common scenarios found in north Louisiana were sampled for nutrient concentration and quantity in falling litter including leaf, woody, and other debris. Across sites, the well-drained site constitutively contributed more nutrients in litter than the poorly drained sites. Also, the sampling time spanning from March to October had the most litter fall and subsequent nutrient discharge from the trees. Of the five nutrients measured, nitrogen was the largest component followed by potassium. These features in nutrient quantity have broad implications for nutrient management based on site and timing of timber removal. This study provides novel nutrient levels in litter fall of hardwood forests typical along minor stream bottoms.

Davina Cooper: Everyday Utopias: The Conceptual Life of Promising Spaces

Utopian studies can be reawakened to its transformative possibilities by taking seriously the conceptual contributions latent in everyday efforts to live life differently. This is what Davina Cooper seeks to demonstrate in her theoretically innovative encounter with six sites in which people strive to actively live out or ‘actualise’ utopian visions in everyday contexts. The sites selected are an eclectic grouping. Britain’s government-led equality drive of the years 2009–2010 is explored in chapter 3. Nudism and nudist organisations come under the lens in chapter 4, while chapter 5 directs attention to a casual sex venue, the Toronto Women’s and Trans Bathhouse (TWTB). In chapter 6 the alternative currencies initiatives championed in Local Exchange Trading Schemes are examined. The final two chapters guide readers through an imaginative conceptual understanding of practices at Summerhill School (chapter 7) and Hyde Park’s Speakers’ Corner (chapter 8). In looking at these ‘everyday’ utopias, Cooper seeks to move the focus away from literary visions of all-encompassing, radical, dream-like transformations of entire societies. She chooses instead to turn toward sites where utopian aspirations are actually put into practice, albeit on smaller scales and in less comprehensive ways. ‘Everyday,’ in Cooper’s usage, further connotes that participants are, alongside their utopian project involvement, still occupied in the ongoing maintenance of lives or functions that are embedded in the larger scale social institutions of mainstream society. These practical utopias therefore constitute parttime, episodic, or otherwise temporally limited ‘minor stream’ practices. What attracts Cooper to these spaces is the conviction that they constitute fertile sites for

Effect of an Upstream Traffic Signal on the Capacity of a Downstream Two-Way Stop-Controlled Intersection

This paper investigates the platoon dispersion model that is part of the Highway Capacity Manual 2010 (HCM 2010) and is used to forecast downstream traffic flows for analyzing both signalized and two-way stop-controlled (TWSC) intersections. The paper focuses on the effect of platoon dispersion on proportion of time blocked, conflicting flow rate, and capacity flow rate for the major street left-turn movement at a TWSC intersection. Existing HCM 2010 methodology shows little effect on conflicting flow or capacity for various distances downstream from the signalized intersection. Two methods are suggested for computing the conflicting flow and capacity of minor stream movements at a TWSC intersection that have more desirable properties than the existing HCM method. Further, if the existing HCM 2010 method is retained, results suggest that the upstream signals model be dropped from the HCM method for TWSC intersections.

Estimation of Critical Gap Based on Raff’s Definition

Critical gap is an important parameter used to calculate the capacity and delay of minor road in gap acceptance theory of unsignalized intersections. At an unsignalized intersection with two one-way traffic flows, it is assumed that two events are independent between vehicles' arrival of major stream and vehicles' arrival of minor stream. The headways of major stream follow M3 distribution. Based on Raff's definition of critical gap, two calculation models are derived, which are named M3 definition model and revised Raff's model. Both models use total rejected coefficient. Different calculation models are compared by simulation and new models are found to be valid. The conclusion reveals that M3 definition model is simple and valid. Revised Raff's model strictly obeys the definition of Raff's critical gap and its application field is more extensive than Raff's model. It can get a more accurate result than the former Raff's model. The M3 definition model and revised Raff's model can derive accordant result.

Estimation of major stream delays with a limited priority merge

The purpose of this paper is to develop an estimation model for major stream delays at an unsignalized intersection under limited priority conditions. The key idea of this paper is that, when the minor stream drivers accept smaller major stream gaps, some drivers on the major road have to slow down their speeds and adjust their relative positions to avoid traffic accidents, incurring some delays. Assuming that headways in the major stream follow the M3 distribution, the delay for the first major stream vehicle after a limited priority merge is presented using acceptance gap theory and probability theory, and then recursive models are developed for the following major stream vehicles before the next merge. Finally, the precision of the method proposed in this paper is calibrated using field survey data from Changchun city, China, and the results show that the maximum, minimum, and average relative error of the 12 samples are approximately 30.38%, 9.04%, and 18.97%, respectively.

Filamentous Algae of a Hill Stream Of Kerala, India

The diversity of filamentous algal flora of a minor stream of Thodupuzha river, Kerala was studied. During the study period thirteen freshwater algal species were observed. They comprised species of Cyanobacteria, Chlorophyta and Charophyta. Presence of certain algae can indicate the pollution status in the stream. Key Words-Stream, Cyanobacteria, Chlorophyta, Charophyta., Filamentous algae

Novel Methods and the Maximum Likelihood Estimation Technique for Estimating Traffic Critical Gap

SUMMARYMost unsignalised intersection capacity calculation procedures are based on gap acceptance models. Accuracy of critical gap estimation affects accuracy of capacity and delay estimation. Several methods have been published to estimate drivers' sample mean critical gap, the Maximum Likelihood Estimation (MLE) technique regarded as the most accurate. This study assesses three novel methods; Average Central Gap (ACG) method, Strength Weighted Central Gap method (SWCG), and Mode Central Gap method (MCG), against MLE for their fidelity in rendering true sample mean critical gaps. A Monte Carlo event based simulation model was used to draw the maximum rejected gap and accepted gap for each of a sample of 300 drivers across 32 simulation runs. Simulation mean critical gap is varied between 3s and 8s, while offered gap rate is varied between 0.05veh/s and 0.55veh/s. This study affirms that MLE provides a close to perfect fit to simulation mean critical gaps across a broad range of conditions. The MCG method also provides an almost perfect fit and has superior computational simplicity and efficiency to the MLE. The SWCG method performs robustly under high flows; however, poorly under low to moderate flows. Further research is recommended using field traffic data, under a variety of minor stream and major stream flow conditions for a variety of minor stream movement types, to compare critical gap estimates using MLE against MCG. Should the MCG method prove as robust as MLE, serious consideration should be given to its adoption to estimate critical gap parameters in guidelines. Copyright © 2012 John Wiley & Sons, Ltd.

Gap Acceptance at Priority-Controlled Intersections

Critical gap is the threshold by which drivers in the minor stream judge whether to accept a gap. If the gap is larger than critical gap, drivers accept it and enter the intersection; otherwise, drivers reject the gap and wait for the next gap. At a priority-controlled intersection, critical gap is usually considered as a fixed value or to follow a certain distribution. The major stream and minor stream are both one-way traffic flows at the priority-controlled intersection. Vehicles in the major stream have priority to run into conflict sections, and vehicles in the minor stream can enter conflict sections during the larger gap of two successive vehicles in the major stream. The capacity of minor roads is the maximum number of vehicles that can pass the intersection during a special period under prevailing roadway, traffic, and control conditions. Under a few assumptions, the survey method of rejected gaps and accepted gaps was designed. Four new calculation models of the critical gap are proposed. The probability function of rejected gap and accepted gap can be deduced by exponential rejected proportion function. Some important relations among variables of these functions can be obtained. The typical capacity functions were improved in terms of accepted proportion function.

Stand-Level Growth and Yield Component Models for Red Oak–Sweetgum Forests on Mid-South Minor Stream Bottoms

Abstract Greater emphasis is being placed on Southern bottomland hardwood management, but relatively few growth and yield prediction systems exist that are based on sufficient measurements. We present the aggregate stand-level expected yield and structural component equations for a red oak (Quercus sectionLobatae)-sweetgum (Liquidambar styraciflua L.) growth and yield model. Measurements from 638 stand-level observations on 258 distinct permanent growth and yield plots collected in 1981, 1988, 1994, and 2006 in minor stream bottoms in Mississippi and Alabama provided data for model development. Equations for average height of dominant and codominant red oaks, trees/ac, arithmetic mean diameter, quadratic mean diameter, and volume were selected on the basis of significance of independent variables, coefficient of determination, index of fit, and biological validity assessment. These models produce expected average yields for combined species or species groups in naturally developing stands and provide an average baseline for individuals managing their lands for the red oak–sweetgum complex. Models will be integrated with log grade volume and diameter distribution models that are in concurrent development to produce a growth and yield system capable of comparing management alternatives on a financial basis.

Specific features of the flow of a two-phase stream in a grainy bed of a separator

The structure of a two-phase stream in a regular grainy bed of a separator was analyzed. A two-phase emulsion stream in a grainy bed transforms into a stream of two mutually permeable continuous phases with a highly developed and nondegenerate (i.e., not varying noticeably with time) phase boundary surface, which creates favorable conditions both for induced coalescence of emulsion contaminations and for mass exchange between the streams. High retaining power of a grainy bed toward minor stream and the corresponding differences in the flow velocities give rise to a braking effect for impurities adsorbed on the phase boundary, which allows the use of the separator for removing solid phase particles from the product stream. The possibility of removing carbon black particles from a stream simulating a spent nuclear fuel solution was demonstrated.

The 2006 Orionid outburst imaged by all-sky CCD cameras from Spain: meteoroid spatial fluxes and orbital elements

Abstract By using high-resolution low-scan-rate all-sky CCD cameras, the SPanish Meteor Network (SPMN) detected an outburst of Orionid meteors associated with comet 1P/Halley on 2006 October 20–21. This detection was made possible due to the operational concept of the SPMN that involves continuous monitoring of meteor activity throughout the year. Accurate heliocentric orbits have been obtained for three meteors imaged simultaneously from two stations during the outburst. Additional astrometry of 33 single-station meteors indicates that the activity was produced from a conspicuous geocentric radiant located at α= 922 ± 05 and δ=+154 ± 06 which is similar to the radiant observed during the 1993 Orionid outburst despite the fact that the last one peaked on a different date. The radiant position obtained by the SPMN is consistent with that derived from digital pictures taken a few hours before from Ankara (Turkey). The extent of the outburst (a background of bright meteors was observed over several days), its absence in other years, and the orbital period of the three Orionid orbits suggest that the outburst could be produced by meteoroids trapped in resonances with Jupiter but additional data are required. The SPMN's continuous coverage of meteor activity allowed the identification of the main sources of meteors during 2006 October: mostly due to the Orionid stream, the two branches of the Taurid stream associated with comet 2P/Encke, and the δ Aurigids. Surprisingly, once a detailed analysis of the double-station video meteors was completed, some additional minor stream activity was discovered, that is, the ν Aurigids. In consequence, we also present two accurate orbits of this unexpected, but previously identified, minor shower.