Vertical Elevation Research Articles

The application of urban rail transit station connection guidelines in mountain city pedestrian transfer

Rail transit takes the advantage of large volume and fast speed as the first choice for many people to travel, and the way of pedestrian transfer is the preferred way for residents of mountainous cities. Compared with plain cities, the sharing rate of pedestrian transfer in mountainous cities is higher. However, due to the large vertical elevation difference in most mountainous cities and the urban characteristics of group development, there are problems of poor connectivity of pedestrian network, inadequate interchange crossing facilities and large bypass distance in the pedestrian transfer in mountainous cities, which causes potential safety hazards and inadequate convenience for pedestrians to travel. By redefining the actual transfer distance and the planning and design scope, this paper analyses the pedestrian transfer characteristics of mountainous cities from a psychological point of view. Taking Chongqing as a typical mountainous city as an example, based on the newly issued Guidelines for Connecting Rail Transit in Chongqing, the application of the Guidelines in actual projects is analysed to prove the generalization of the Guidelines.

Some probabilistic properties of surf parameter

• Average statistical properties of surf parameters. • Surf parameter for individual waves. • Spectral surf parameter representing a sea state characteristic. • Results using data typical for field conditions are provided. • Example of calculating wave runup elevation. This article is supplementary to Myrhaug (2018) and presents some probabilistic properties of the surf parameter for individual waves and the spectral surf parameter for sea states by using distributions based on data from the Norwegian continental shelf. The average statistical features given by the mean value and the standard deviation of the two surf parameters are considered. Examples of results for the surf parameter are provided for a Phillips spectrum and a family of JONSWAP spectra for wind sea, and for sea states using a joint frequency table of significant wave height and mean zero-crossing wave period for combined wind sea and swell. The spectral surf parameter results are obtained by using a joint distribution of significant wave height and spectral surf parameter, and the mean statistical properties are given for joint frequency tables of significant wave height and mean zero-crossing wave period from three deep water locations on the Norwegian continental shelf. It is also demonstrated how the results can be applied to calculate the vertical wave runup elevation for breaking waves.

Large wood inhibits debris flow runout in forested southeast Alaska

AbstractDue to their potentially long runout, debris flows are a major hazard and an important geomorphic process in mountainous environments. Understanding runout is therefore essential to minimize risk in the near‐term and interpret the pace and pattern of debris flow erosion and deposition over geomorphic timescales. Many debris flows occur in forested landscapes where they mobilize large volumes of large woody debris (LWD) in addition to sediment, but few studies have quantitatively documented the effects of LWD on runout. Here, we analyze recent and historic debris flows in southeast Alaska, a mountainous, forested system with minimal human alteration. Sixteen debris flows near Sitka triggered on August 18, 2015 or more recently had volumes of 80 to 25 000 m3 and limited mobility compared to a global compilation of similarly‐sized debris flows. Their deposits inundated 31% of the planimetric area, and their runout lengths were 48% of that predicted by the global dataset. Depositional slopes were 6°–26°, and mobility index, defined as the ratio of horizontal runout to vertical elevation change, ranged from 1.2 to 3, further indicating low mobility. In the broader southeast Alaskan region consisting of Chichagof and Baranof Islands, remote sensing‐based analysis of 1061 historic debris flows showed that mobility index decreased from 2.3–2.5 to 1.4–1.8 as average forest age increased from 0 to 416 years. We therefore interpret that the presence of LWD within a debris flow and standing trees, stumps, and logs in the deposition zone inhibit runout, primarily through granular phenomena such as jamming due to force chains. Calibration of debris flow runout models should therefore incorporate the ecologic as well as geologic setting, and feedbacks between debris flows and vegetation likely control the transport of sediment and organic material through steep, forested catchments over geomorphic time. © 2020 John Wiley & Sons, Ltd.

Automated operational logging plan considering multi-criteria optimization

Multiple goals should be considered while planning and executing forest management. This study proposes a new multidimensional framework for a precision forestry approach assisted by airborne laser scanning data (ALS). Therefore, successful management operations become a key element in the process of promoting protection through sustainable development. Thirteen relevant variables were derived from ALS data, such as: canopy height, terrain topography, relative vegetation density, forest gaps, slope restrictions, skidder restrictions, load truck restrictions, topographic wetness, flow accumulation, horizontal distance to drainage, vertical elevation from drainage, stream and headspring restrictions. Four different scenarios for the management plan optimization were studied: shortest distance, forest conservation, soil conservation and all combined. Results showed that the detailed forest information from ALS point clouds is useful to indicate regions not suitable for forest operations. Failure to properly consider the different factors involved may result in inadequate infrastructures, lower operational performance and constant re-planning requirements.

The role of spectral cues in vertical plane elevation perception

The role of spectral cues in vertical plane elevation perception

A Method for Optimising Superdirectivity of Coupled Meta-Atoms via Planar Directivity Evaluation

We propose a simple and rapid way of optimising directivity in metamaterial-inspired endfire antenna arrays with strong inter-element coupling. We introduce, in addition to the traditional 3D directivity, also its planar equivalents defined as the ratio of the power density in the desired endfire direction to the average power density calculated either in the horizontal (azimuthal) or vertical (elevation) plane. Using dimers of magnetically coupled split-ring resonators with only one element driven by an external source, we derive conditions that must be satisfied in order to realise superdirective current distributions. The superdirective conditions link the quality factor of the resonators and their coupling constant to the array size and the operating frequency. We demonstrate that a rapid measurement in the azimuthal plane can be used as a reliable indicator for whether the superdirective conditions for the 3D directivity are satisfied. Analytical calculations are verified by CST simulations in the MHz frequency range for meta-atoms of circular and square shape. Our method can be extended to arrays comprising larger number of meta-atoms of various shape and would enable rapid prototyping of 3D-printed meta-atoms with desired radiation properties.

Effect of new tunnel construction on structural performance of existing tunnel lining

This paper presents the results of a three-dimensional numerical investigation into the effect of new tunnel construction on structural performance of existing tunnel lining. A three-dimensional finite difference model, capable of modelling the tunnel construction process, was adopted to perform a parametric study on the spatial variation of new tunnel location with respect to the existing tunnel with emphasis on the plan crossing angle of the new tunnel with respect to the existing tunnel and the vertical elevation of the new tunnel with respect to the existing one. The results of the analyses were arranged so that the effect of new tunnel construction on the lining member forces and stresses of the existing tunnel can be identified. The results indicate that when a new tunnel underpasses an existing tunnel, the new tunnel construction imposes greater impact on the existing tunnel lining when the two tunnels cross at an acute angle. Also shown are that the critical plan crossing angle of the new tunnel that would impose greater impact on the existing tunnel depends on the relative vertical location of the new tunnel with respect to the existing one, and that the overpassing new tunnel construction scenario is more critical than the underpassing scenario in view of the existing tunnel lining stability. Practical implications of the findings are discussed.

Testing Predictions from an Environmental Stress Model on Macroinvertebrate Diversity Across Rocky Intertidal Elevation Gradients in Mumbai, India

Intertidal organisms distributed in different zones experience strong environmental stress due to various biotic and abiotic factors. Environmental stress model (ESM) predicted that overall species richness and diversity should follow a unimodal trend along the vertical elevation gradient. In the present study, species richness and diversity of macroinvertebrates (molluscs and crustaceans) were measured on a rocky shore of Mumbai, the west coast of India. Data on species abundance were collected for two years (January 2005 to December 2006) after fixing three transects from high-to-low-shore zones based on the tidal heights. Quadratic regression analysis was applied to examine the pattern of variation in overall species richness and diversity across the stress gradient. The analysis revealed that both the variables followed unimodal trends across elevations and suggested that ESM predictions can also be applied to taxonomic groups besides different functional groups of intertidal organisms. It was also found that ESM can be useful in predicting local species richness and diversity as a function of environmental stress and helpful in providing a better understanding of distribution and dynamics of communities at local scale.

Wave height vs. elevation effect on macroalgal dominated shores: an intercommunity study

Sheltered intertidal environments are characterized by highly diversified macroalgal communities which vary over short spatial scales depending on various environmental pressures. In this study, relations between wave heights and vertical elevation were analyzed in order to identify the respective roles of these factors on the structure of macroalgal communities. We measured both wave heights and elevation on six macroalgal communities of three Northeast Atlantic rocky shores. The effects of these structuring factors on seaweed communities were seasonally evaluated in early summer and late autumn using pressure recorders and digital terrain model data. Results reveal that waves were higher during late autumn than in early summer. At shore-scale, elevation was the main factor determining both the structure and the species composition of the macroalgal communities (13.7% of total variance explained), while hydrodynamics played a lower, although significant role (< 1% of the total variance). Based on the cover of canopy-forming species, intertidal macroalgal communities can be grouped into three clusters, corresponding to three height levels on the shore (higher, middle, and lower shore). Canopy composition and structure were mainly explained by the effect of elevation (45%) in the higher level of the shore and by both elevation (42%) and wave height (2.5%) in the middle shore. On the contrary, low shore communities were affected by a more balanced effect of elevation (explaining 14% of the total variance and wave height associated with site effect explaining 15% of such effect). This study gave new insights of how hydrodynamics and elevation condition the extension of macroalgal communities.

Understanding tidal marsh trajectories: evaluation of multiple indicators of marsh persistence

Robust assessments of ecosystem stability are critical for informing conservation and management decisions. Tidal marsh ecosystems provide vital services, yet are globally threatened by anthropogenic alterations to physical and biological processes. A variety of monitoring and modeling approaches have been undertaken to determine which tidal marshes are likely to persist into the future. Here, we conduct the most robust comparison of marsh metrics to date, building on two foundational studies that had previously and independently developed metrics for marsh condition. We characterized pairs of marshes with contrasting trajectories of marsh cover across six regions of the United States, using a combination of remote-sensing and field-based metrics. We also quantified decadal trends in marsh conversion to mudflat/open water at these twelve marshes. Our results suggest that metrics quantifying the distribution of vegetation across an elevational gradient represent the best indicators of marsh trajectories. The unvegetated to vegetated ratio and flood-ebb sediment differential also served as valuable indicators. No single metric universally predicted marsh trajectories, and therefore a more robust approach includes a suite of spatially-integrated, landscape-scale metrics that are mostly obtainable from remote sensing. Data from surface elevation tables and marker horizons revealed that degrading marshes can have higher rates of vertical accretion and elevation gain than more intact counterparts, likely due to longer inundation times potentially combined with internal recycling of material. A high rate of elevation gain relative to local sea-level rise has been considered critical to marsh persistence, but our results suggest that it also may serve as a signature of degradation in marshes that have already begun to deteriorate. This investigation, with rigorous comparison and integration of metrics initially developed independently, tested at a broad geographic scale, provides a model for collaborative science to develop management tools for improving conservation outcomes.

Respire: Virtual Reality Art with Musical Agent Guided by Respiratory Interaction

Respire is an immersive art piece that brings together three components: an immersive virtual reality (VR) environment, embodied interaction (via a breathing sensor) and a musical agent system to generate unique experiences of augmented breathing. The breathing sensor controls the user’s vertical elevation of the point of view under and over the virtual ocean. The frequency and patterns of breathing data guide the arousal of the musical agent, and the waviness of a virtual ocean in the environment. Respire proposes an intimate exploration of breathing through an intelligent mapping of breathing data to the parameters of visual and sonic environments.

Instructions to attend to an observed action increase imitation in autistic adults.

This study investigated whether reduced visual attention to an observed action might account for altered imitation in autistic adults. A total of 22 autistic and 22 non-autistic adults observed and then imitated videos of a hand producing sequences of movements that differed in vertical elevation while their hand and eye movements were recorded. Participants first performed a block of imitation trials with general instructions to imitate the action. They then performed a second block with explicit instructions to attend closely to the characteristics of the movement. Imitation was quantified according to how much participants modulated their movement between the different heights of the observed movements. In the general instruction condition, the autistic group modulated their movements significantly less compared to the non-autistic group. However, following instructions to attend to the movement, the autistic group showed equivalent imitation modulation to the non-autistic group. Eye movement recording showed that the autistic group spent significantly less time looking at the hand movement for both instruction conditions. These findings show that visual attention contributes to altered voluntary imitation in autistic individuals and have implications for therapies involving imitation as well as for autistic people's ability to understand the actions of others.

Vertical Distribution and Elevation Preference for the Breeding of Fairy Pittas on Jeju Island, Korea

Elevation often becomes an important component in the breeding site selection of forest birds because it may affect individual fitness. To understand how the threatened fairy pitta (Pitta nympha Temminck &amp; Schlegel) selects a particular elevation for breeding and whether the pitta achieves better reproductive performance in its preferred elevation, we surveyed for the presence of breeding pittas and recorded their reproductive performances at six different elevation zones on Mount Halla in Jeju Island, Korea. We expected that preference for breeding sites and reproductive performance would gradually decrease with increasing elevation. In fact, 73 presence and 78 absence records indicated no preference for breeding sites at elevations lower than 400 m. However, forest habitats between 400 and 600 m were strongly preferred, while locations above 800 m were clearly avoided. The egg-laying date was significantly earlier at lower elevations, but other measures of reproductive performance did not differ between the preferred and non-preferred elevations. Contrary to our expectations, this indicates that there was no clear advantage to a pitta’s reproductive performance based on elevation preference. Our findings suggest that the inherent optimal selection for the best reproductive outcomes was not a key driving factor for the pattern of elevation preference observed, and that the pitta’s preference might be a response to external and environmental factors such as climate conditions. The reduction of anthropogenic impacts by mitigating human–pitta conflicts at lower elevations, such as accidental non-reproductive mortality and forest loss, would help enhance the conservation of the fairy pitta on Jeju Island, a stronghold of this threatened species in Korea.

Parametric Study of Seismic Response Analysis of High Rise Structure

High rise structures with complex planning and irregular vertical elevations are trending nowadays. Such high rise structures are more susceptible to seismic forces which are quite devastating and cause a huge loss to human lives and property. Hence it is very important to study the behavior of such structure to help structural engineers to create better earthquake resistant design. The usefulness of the shear walls in the structural planning of the multistory buildings to resist the lateral forces has been recognized long back. Shear walls also dissipates a great amount of energy if detailed properly, however there are many factors such as placement of shear walls, its thickness, aspect ratio, plan of the building which affects the response of the building towards lateral loads. In the present study attempt is made to study the effect of different location of shear walls on the response of the building in terms of time period and maximum displacement. The detailed investigation is carried out for zone II of Seismic zones of India as per IS 1893 (part 1):2016, considering primary loads (dead, live and seismic loads) and their combinations with appropriate load factor. Analysis is carried out in ETABS 2016. Further a case study of a U-shaped plan is carried out, to reduce the torsional irregularity structural wall system with spandrels and seismic joints were provided at certain locations.

Air-water interaction and characteristics in breaking bores

A tidal bore is an unsteady rapidly-varied open channel flow characterised by a rise in water surface elevation in estuarine zones, under spring tidal conditions. After formation, the bore is traditionally analysed as a hydraulic jump in translation and its leading edge is characterised by a breaking roller for Froude number Fr1 > 1.3–1.5. The roller is a key flow feature characterised by intense turbulence and air bubble entrainment. Detailed unsteady air-water flow measurements were conducted in a breaking bore propagating in a large-size channel, using an array of three dual-tip phase detection probes and photographic camera. The data showed a relatively steep roller, with a short and dynamic bubbly flow region. Air entrainment took place in the form of air entrapment at the roller toe, air-water exchange across the roller 'free-surface', spray and splashing with dynamic water drop ejection and re-attachment, roll up and roll down of water 'tongues' engulfing air pockets. The roller free-surface profile and characteristics were comparable to observations in stationary hydraulic jumps and steady breaker, for similar flow conditions. Within the roller, the amount of entrained air was quantitatively small for Froude number Fr1 = 2.2. The number of air bubbles was limited, with between 5 and 20 bubbles per phase-detection probe sensor detected at each vertical elevation. The entrained air bubble chord lengths spanned over several orders of magnitude, with a large proportion of clustered bubbles. Overall, the study highlighted the three-dimensional nature of the air-water roller motion and strong evidence of the in-homogeneity of the turbulent air-water mixture.

Physical Modeling of Horizontal and Vertical Tsunami Forces on the Elevated Overland Structure

Park, H.; Cox, D.T., and Shin, S., 2019. Physical modeling of horizontal and vertical tsunami forces on the elevated overland structure. In: Lee, J.L.; Yoon, J.-S.; Cho, W.C.; Muin, M., and Lee, J. (eds.), The 3rd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 91, pp. 51-55. Coconut Creek (Florida), ISSN 0749-0208.In this study, two-dimensional hydraulic model tests were conducted to investigate the characteristics of the force of tsunami waves on the simplified box-type elevated structure. The vertical elevation of the structure was changed to investigate the relation between the wave force and the air gap. The tsunami waves were generated by using the error function with the full-stroke of the wave paddle to maximize inundation. The horizontal and vertical wave forces and pressures on the structure by the tsunami waves were measured, and the relation between the maximum wave force, air gap and the incident wave condition was derived. Using the measured maximum horizontal wave force from the different wave conditions, the empirical formula of the non-dimensionalized horizontal wave force as a function of the surf similarity parameter was obtained. It was found that the horizontal wave force is inversely proportional to the surf similarity parameter in the case of the unelevated structure. The experimental results also showed that the ratio of the horizontal force to the vertical force is larger in the case of broken and breaking wave conditions in the case of the elevated structures.

SIGNIFICANCE OF PREOPERATIVE EXTERNAL LIMITING MEMBRANE HEIGHT ON VISUAL PROGNOSIS IN PATIENTS UNDERGOING MACULAR HOLE SURGERY.

To investigate the association between the vertical elevation of the external limiting membrane (ELM) and visual outcome in patients undergoing surgery for idiopathic full-thickness macular hole. Retrospective observational study of a consecutive cohort of patients undergoing vitrectomy to treat macular hole. The greatest vertical height of the central ELM above the retinal pigment epithelium (ELM height) was measured on spectral domain optical coherence tomography preoperatively. The relationship of ELM height to other preoperative and postoperative variables, including macular hole width and height, and visual acuity was analyzed. Data from 91 eyes of 91 patients who had undergone successful hole closure were included. The mean ELM height was 220 μm (range 100-394). There were significant correlations between the ELM height and the diameter of the hole, hole height, and worsening preoperative visual acuity. For holes less than 400 μm in width, better postoperative visual acuity was significantly predicted by a lower ELM height. The ELM height varies widely in idiopathic macular hole. It is higher in eyes where the hole is wider and also when the hole itself is higher. For holes of less than 400 μm in width, a lower ELM height is a strong independent predictor of a good postoperative outcome.

Determination of Dangerous Parts of the Energy Transmission Line by the Canopy Height Model Produced from LiDAR Data

LiDAR (Light Detection and Ranging) technique is preferable method to determine vertical metric values of High Voltage Transmission Lines (HVTL) in global regions and steep land. The importance of these facilities is increasing day by day because of the necessity of electricity energy in our daily life. Determination of vertical heights is an important problem especially in forested areas after construction. In this study, metric values of vegetation which violate vertical safety limits under voltage wires were determined by using Canopy Height Model (CHM) using LiDAR data. As a study area 450x150 m2 was selected the existing voltage line in the region between Beykoz District and Çekmeköy located on the Anatolian side of Istanbul. Firstly, it has been made conductive classification of HVTL that is using LiDAR classification techniques. Also it is determined the dangerous limits of trees and vegetation in HVTL vertical oscillation. As a result the comparison of the values of the vertical elevation with the local methods and obtained from the LiDAR data yielded a Root Mean Square Error (RMSE) value of 0.36m was found.

Innovative Design of a Vertical and Transverse Elevator in Double Shafts, Based on TRIZ Theory

Innovative Design of a Vertical and Transverse Elevator in Double Shafts, Based on TRIZ Theory

A frequency distributed dissipation model for canopies

Existing dissipation models (bulk and frequency distributed) describing the wave attenuation in canopies rely on a characteristic shape of the velocity profile and corresponding characteristic frequency, which is integrated analytically over the height of the canopy. This means that all frequencies higher than the characteristic peak frequency are assigned excessive dissipation, while all frequencies lower than the characteristic peak frequency are assigned insufficient dissipation.The present work presents a new dissipation model, which is given in a closed form based on the surface elevation spectrum, Sη. The model calculates the frequency dependent dissipation at a given vertical elevation z, which is numerically integrated over the height of the canopy. A comparison with existing bulk dissipation models shows that there are large differences between the existing models and the present work. These differences are particularly noticeable for realistic peak enhancements factors for the JONSWAP spectrum (1.0–10.0) and submerged canopies.A comparison with the frequency distributed dissipation model in the spectral wave model SWAN is also presented and the present model distinguishes itself by naturally incorporating a cut-off frequency above which the dissipation effectively vanishes. This offers a more realistic frequency distribution of the dissipation. The frequency distribution of the dissipation and the existence of a frequency cut-off is verified with experimental data.