Plan Geometry Research Articles

Comparative investigation of the costs and performances of torsional irregularity structures under seismic loading according to TEC

The poor seismic performance of reinforced concrete buildings during the latest earthquakes has become a serious issue in the building industry in Turkey. This case, designing new buildings without structural irregularities against earthquake loads reveals to be quite significant. This study mainly is focused on the effects of different torsional irregularities on construction costs and earthquakes performance of reinforced concrete buildings. In that respect, structural torsional irregularities are investigated based on the Turkish Earthquake Code. The study consists of major eight main parametric models. In this models consist of totally 49 models together with the variations in the number of storey. With this purpose, the earthquake performances and construction costs (especially steel quantities) of reinforced concrete buildings which having different structural torsional irregularities were obtained with the help of Sta4-CAD program. Each model has been analyzed by both the methods of equivalent earthquake loading and dynamic analysis. The obtained results reveal that the model-1 which has lower torsional irregularity coefficient shows the best earthquake performance owing to its regular plan geometry. Also, economical comparisons on costs of the torsional irregularity are performed, and results-recommendations are given.

SU‐E‐T‐271: Quantitative Analysis of Correlations Between Patient Geometry and Dosimetric Variation for Prostate Cancer Cases Using PCA and Step‐Wise Regression

Purpose:To study the potential correlations between patient geometry information and corresponding plan dosimetric variation in terms of planning target volumes (PTVs) coverage and organs‐at‐risk (OARs) dose sparing for prostate cancer cases.Methods:We extracted dosimetric and geometrical data from twenty‐three clinically acceptable prostate treatment plans. Dosimetric data extracted from each patient was PTV dose‐volume historgram (DVH), and dose‐wall‐volume histograms (DWHs) for the bladder and rectum. Geometrical data extracted was the PTV volume, OAR volumes, and COP (closeness of OAR to PTV). COP is the weighted sum of the overlapping wall histogram (OWH). OWH is proposed to describe the complex spatial relationship between PTV and a hollow organ. Principal component analysis (PCA) was performed on the (inverted and downsampled) DVH and DWH data from all the patients. We then fit the patient geometry features to first 3 PCA scores using a step‐wise regression analysis. The fitting results in a mapping from plan geometry information to dosimetric features.Results:First 3 PCA modes were found corresponded to clinically relevant features, indicating a tradeoff between homogenous coverage of the PTV and higher OAR dose, higher average dose to the OARs and PTV, and bladder and rectum dose tradeoffs along the first, second and third principal component respectively. Step‐wise regression results show baldder surface volume and OAR COP more relevant to the 1st PCA modes score rather than other features with p‐value of 0.58 for bladder volume, 0.26 for bladder COP, 0.98 for rectum COP, and less than 0.025 for other features after t‐test.Conclusion:Quantitative correlations were established between patient geometry and corresponding plan dosimetric variation in terms of PTV coverage, trade‐offs between PTV coverage and OAR dose sparing and trade‐offs between different OAR dose sparing. Thus a new patient dosimetric variation tendency can be predicted and act as guidance for setting up planning goals.

Towards adaptive radiotherapy for head and neck patients: validation of an in-house deformable registration algorithm

The purpose of this work is to validate an in-house deformable image registration (DIR) algorithm for adaptive radiotherapy for head and neck patients. We aim to use the registrations to estimate the "dose of the day" and assess the need to replan. NiftyReg is an open-source implementation of the B-splines deformable registration algorithm, developed in our institution. We registered a planning CT to a CBCT acquired midway through treatment for 5 HN patients that required replanning. We investigated 16 different parameter settings that previously showed promising results. To assess the registrations, structures delineated in the CT were warped and compared with contours manually drawn by the same clinical expert on the CBCT. This structure set contained vertebral bodies and soft tissue. Dice similarity coefficient (DSC), overlap index (OI), centroid position and distance between structures' surfaces were calculated for every registration, and a set of parameters that produces good results for all datasets was found. We achieve a median value of 0.845 in DSC, 0.889 in OI, error smaller than 2 mm in centroid position and over 90% of the warped surface pixels are distanced less than 2 mm of the manually drawn ones. By using appropriate DIR parameters, we are able to register the planning geometry (pCT) to the daily geometry (CBCT).

The effect of architectural form on the earthquake behavior of symmetric RC frame systems

In this study, structural irregularities in plan, which has a considerable effect on earthquake behavior of buildings, have been investigated in detail based on Turkish Earthquake Code 2007. The study consists of six main parametric models and a total of 144 sub-models that are grouped based on RC structural systems such as frame, frame + rigid core, frame with shear wall, and frame with shear wall + rigid core. All models are designed to have both symmetrical plan geometry and regular rigidity distribution. Changes in the earthquake behavior of buildings were evaluated according to the number of storeys, number of axes and the configuration of structural elements. Many findings are obtained and assessed as a result of the analysis for each structural irregularity. The study shows that structural irregularities can be observed in completely symmetric buildings in terms of plan geometry and rigidity distribution.

Triple Band Parasitic Array Antenna for C-X-Ku-Band Application Using Out-of-Phase Coupling Approach

Triple band parasitic array antenna for C-X-Ku-band application is presented. The proposed antenna is designed using the concept of parasitic array and out-of-phase coupling approach. The objects of research are to optimize total inductance of geometry by using out-of-phase inductance approach. The out of phase inductance of geometry consists of using two U-patches novel director on the left side of geometry, appropriate dimension of ground plan, and gap coupling between parasitic and active patches. The dimension of the ground plan geometry is 0.5λ mil × 0.5154λ mil. The usable impedance bandwidth of design antenna is “5.8 GHz to 18 GHz” (102% impedance bandwidth) and gain enhancement is up to 11.8 dBi. The proposed antenna can be used for X-Ku band and C-band applications. Both simulated and measured results are presented, which are in good agreement. The proposed antenna was fabricated with a thin copper layer printed on a thin lossy FR4 substrate for low-cost production.

Three-dimensional funicular analysis of masonry vaults

This paper introduces a new computational equilibrium analysis method for unreinforced masonry vaults, which extends Thrust Network Analysis using structural matrix analysis and efficient optimization strategies. By identifying independent states of equilibrium of funicular networks with any topology and fixed plan geometry, a robust and efficient solving algorithm is presented that allows practical limit analysis of (historic) masonry vaults with complex geometry under parallel loading conditions by fitting a provided geometrical target, e.g. the vault's mid surface. The presented framework can be seen as a strong foundation for practical equilibrium analysis of vaulted masonry.

Performance Evaluation of Four-Sided Square Wind Catchers with Different Geometries by Numerical Method

The extensive enhance of using air conditioning to cool and ventilate buildings in hot - arid climate regions have turned into an actual crisis since these systems consume high load of electricity. Recently, green ventilation features such as wind catchers have been utilized as a solution in order to improve indoor air quality and decrease energy consumption. The most common ventilation device in hot and hot-humid areas of Iran was wind catcher or Badgir. This study is an outline of the results of a research on the wind catcher element in the traditional architecture of Iran. An appraisal of the wind towers' individuality with prominence on their morphology is presented and classification of the wind towers based on their physical characteristic and parameters are thus proposed. This paper also presents a limited wind driven simulation results which shows the impact of different square wind catcher's plan geometry on the indoor ventilation rate. The simulations accomplished using computational fluid dynamics (CFD), reveal the effect of four different square wind catchers on the indoor ventilation rate.

TH-C-137-10: Development of a GPU Research Platform for Automatic Treatment Planning and Adaptive Radiotherapy Re-Planning

Purpose: To develop a research platform called SCORE (Super Computing Online Re‐planning Environment) for automatic treatment planning and adaptive radiotherapy re‐planning based on GPU. Methods: Our software is a Graphical User Interface (GUI) based on the Qt framework that allows users to easily and quickly create a new treatment plan based on a reference plan. It consists of several modules, including loading plan and patient geometry from DICOM RT files, automatic and manual rigid registration, deformable registration for contour propagation, previous plan based automatic plan optimization, physician‐driven plan tuning, final dose calculation, and plan exporting in DICOM RT format. For automatic planning, a reference plan is identified from a library of previously delivered plans and it is used to guide the optimization process. For adaptive radiotherapy re‐planning, the original plan of the same patient is used as the reference plan to guide the optimization process to generate a new plan on the new patient geometry defined by either a new CT or Cone‐Beam CT image. All the computation modules have been implemented in CUDA to achieve high efficiency. The results for each step of the workflow can be visualized for review, revision, and approval. Results: SCORE has been well tested and validated for prostate and head/neck cancer cases. The validation was done by comparing SCORE plans against the same plans with re‐calculated dose distributions and DVHs using a commercial planning system. We found that SCORE can generate clinically optimal treatment plans that are realistic and deliverable. The plans can be automatically created in only a few minutes, followed by another few minutes of physician fine‐tuning using an interactive GUI. Conclusion: We have developed a very efficient and user‐friendly GPU‐based research platform that can be used for clinical research on automatic treatment planning and adaptive radiotherapy re‐planning.

Structural Configuration and Building Energy Performance

The civilengineering andarchitecturalcommunities arehighlyfocusedthesedays ondesigningbuildingsthatmaximizeutilization ofenergyavailablefromnaturalresourcesthroughmeanssuchaspassivesolarheatingandpassiveventilationandminimizingtheconsumption ofenergyproducedexternaltothebuildingitself.Indeed,so-callednet-zero-energybuildings,whichwouldrequirenonetenergyinputfortheir operation, have been identified as an aspirational goal for architects and engineers. It has been suggested that for each of the four major climate zones there exists an optimal building morphology,consisting offloor plan geometry and placement of the primary structural system for lateral loads, the structural core or wall, which contains major mechanical services and vertical transportation conduits. This paper presents a quanti- tative study of the effect of building morphology on energy performance in each of the four climate zones. The energy analysis is performed using Autodesk Ecotect Analysis 2011. Four building morphologies are investigated, each representing a high-rise commercial building with equivalent area, height, and material use. For comparison, results are presented in terms of annual sensible heating and cooling loads. A three- dimensional rendering of how the different building types might respond under wind loads is presented to indicate how the environmental and structural performances become coupled when the building is designed onlywith environmental performance in mind.DOI:10.1061/(ASCE) AE.1943-5568.0000103. © 2013 American Society of Civil Engineers. CE Database subject headings: Sustainable development; Energy efficiency; Building design; Solar power. Author keywords: Efficiency; Comfort; Passive solar; Skyscraper; Morphology; Sustainable.

波浪中の弾性平板浮体の運動に関する変分原理

In this paper, variational principles related to motions of an elastic plate in waves considering wave radiation condition at infinity, which are very important in calculations of the elastic response of the pontoon- type floating structure, are discussed. First, Sommerfeld radiation condition at infinity is extended to treat a case with an incident wave. Second, four kinds of variational principles related to motions of the elastic floating plate considering the incident and radiated waves are proposed and clarified the mutual relationship of these variational principles. Third, numerical results for elastic response of a floating plate of rectangular plan geometry in waves, which are obtained by using proposed variational principles, are shown.

An investigation on plan geometries of RC buildings: with or without projections in plan

The interaction of plan geometry and structural configuration, a determinative factor in the earthquake behavior of buildings, has become a serious issue in the building industry in Turkey due to the poor seismic performance of R/C buildings during the latest earthquake. Consequently, designing new buildings without structural irregularities against earthquake loads is proving to be more significant. This study focuses on the effects of plan geometries on earthquake performances of buildings. In that respect, structural irregularities in the plan are investigated in detail based on the Turkish Earthquake Code (TEC 2007). The study is based on five main parametric models and a total of 40 sub-models that are grouped according to their plan geometries with excessive projections such as L-shaped, H-shaped, T-shaped and U-shaped models. In addition to these, a square model without any projections is also generated. All models are designed to have the same storey gross area but with different number of storeys. Changes in the earthquake behavior of buildings were evaluated according to the number of storeys, the projection ratios and the symmetry conditions of each model. The analysis of each structural irregularity resulted in many findings, which were then assessed. The study demonstrates that the square model delivers the best earthquake performance owing to its regular plan geometry.

Analysis and Measurement of Buildability Factors Influencing Rebar Installation Labor Productivity of In Situ Reinforced Concrete Walls

Buildability is one of the most important factors influencing labor productivity. However, an extensive search of the literature revealed a dearth of research into its effects on labor productivity of in situ reinforced concrete construction, especially on the activity levels. Rebar installation is an integral, labor-intensive trade of this type of construction material. Its walls form major parts of reinforced concrete frames, which are typically associated with a higher unit rate cost compared with other structural elements, especially spread foundations and grade and one-way elevated slabs. Therefore, objective of this research is to investigate the effects and relative influence of the rebar diameter, quantity of reinforcement installed, wall thickness, plan geometry, and wall curvature intensity, on rebar installation labor productivity of walls. To achieve this objective, a sufficiently large volume of installation labor productivity data was collected and analyzed using the multiple categorical-regression method. The results obtained show a significant influence of factors investigated on the labor efficiency of the installation operation, which can be used to provide designers feedback on how well their designs consider the requirements of the buildability concept, and the tangible consequences of their decisions on labor productivity. In addition, a set of recommendations are presented, which on implementation, can improve the buildability level of this activity, hence translating into higher labor efficiency and lower labor cost. Moreover, the depicted patterns of factors explored may provide guidance to construction managers for effective activity planning and efficient labor utilization.

Influence of riprap apron shape on spill-through abutments

This technical note focuses on the plan geometry of riprap mattresses to protect spill-through abutments against local scour through edge failure. Two non-standard riprap apron geometries are experimentally studied. The performance of the new geometries is evaluated by comparing it with that of the standard design in terms of apron width and total riprap volume needed to guarantee stability. For comparatively short abutments, it is demonstrated that one of the new proposed geometries allows reductions between 15% and 25% in the total riprap volume without any increase in both design complexity and building difficulty.

Quantifying the relationship between geometric buildability factors and formwork productivity: the case of walls

In today’s economic climate, improving the efficiency of labour has become more pressing than ever. Labour productivity is influenced by several factors, but buildability is among the most important. A thorough search of the literature, however, revealed a dearth of quantitative investigations into its effects on an integral, labour intensive, trade of in situ reinforced concrete material; namely, formwork. Therefore, the objective of this research is to quantify the relationship between: a perimeter configurations b plan geometry c curvature intensity d surface area, and formwork labour productivity of walls, which constitute major parts of many construction projects. To achieve this objective, a large volume of productivity data was collected and analysed using the multiple categorical-regression method. The results obtained show significant effects of the factors investigated on labour productivity, which can be used to provide designers and construction managers with tangible feedback on the impacts of the geometric buildability factors investigated upon the efficiency of operatives.

A low‐dimensional hillslope‐based catchment model for layered groundwater flow

AbstractDespite the strong interaction between surface and subsurface waters, groundwater flow representation is often oversimplified in hydrological models. For instance, the interplay between local or shallow aquifers and deeper regional‐scale aquifers is typically neglected. In this work, a novel hillslope‐based catchment model for the simulation of combined shallow and deep groundwater flow is presented. The model consists of the hillslope‐storage Boussinesq (hsB) model representing shallow groundwater flow and an analytic element (AE) model representing deep regional groundwater flow. The component models are iteratively coupled via a leakage term based on Darcy's law, representing delayed recharge to the regional aquifer through a low conductivity layer. Simulations on synthetic single hillslopes and on a two‐hillslope open‐book catchment are presented, and the results are compared against a benchmark three‐dimensional Richards equation model. The impact of hydraulic conductivity, hillslope plan geometry (uniform, convergent, divergent), and hillslope inclination (0.2%, 5%, and 30%) under drainage and recharge conditions are examined. On the single hillslopes, good matches for heads, hydrographs, and exchange fluxes are generally obtained, with the most significant differences in outflows and heads observed for the 30% slope and for hillslopes with convergent geometry. On the open‐book catchment, cumulative outflows are overestimated by 1–4%. Heads in the confined and unconfined aquifers are adequately reproduced throughout the catchment, whereas exchange fluxes are found to be very sensitive to the hillslope drainable porosity. The new model is highly efficient computationally compared to the benchmark model. The coupled hsB/AE model represents an alternative to commonly used groundwater flow representations in hydrological models, of particular appeal when surface–subsurface exchanges, local aquifer–regional aquifer interactions, and low flows play a key role in a watershed's dynamics. Copyright © 2011 John Wiley & Sons, Ltd.

Synthesis of poly(N‐isopropylacrylamide) under atmospheric pressure plasma conditions

AbstractThis work is focused on obtaining and characterizing thin films of a certain thermosensitive polymer, i.e., poly(N‐isopropylacrylamide). To obtain such polymers dielectric barrier discharge plasma working at atmospheric pressure in plan–plan geometry was used. The plasma parameters were monitored during polymerization reaction by its electrical and optical signals. The obtained films were analyzed by different techniques such as X‐photoelectron spectroscopy, Fourier transform infrared spectroscopy, atomic force microscopy, contact angle, impedance spectroscopy measurements, and light interferometry for thickness measurements. Chemical analyses of obtained films showed that they sort well with the polymers obtained by other methods in literature. It has been proved that plasma polymerized films have a superhydrophilic character at room temperature, the measured contact angle being around 13°, the lower critical solution temperature was also identified at about 30–31°C. The films' thickness for a 10‐min duration deposition was 400 nm. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Dosimetric evaluation of a “virtual” image-guidance alternative to explicit 6 degree of freedom robotic couch correction

Clinical evaluation of a "virtual" methodology for providing 6 degrees of freedom (6DOF) patient set-up corrections and comparison to corrections facilitated by a 6DOF robotic couch. A total of 55 weekly in-room image-guidance computed tomographic (CT) scans were acquired using a CT-on-rails for 11 pelvic and head and neck cancer patients treated at our facility. Fusion of the CT-of-the-day to the simulation CT allowed prototype virtual 6DOF correction software to calculate the translations, single couch yaw, and beam-specific gantry and collimator rotations necessary to effectively reproduce the same corrections as a 6DOF robotic couch. These corrections were then used to modify the original treatment plan beam geometry and this modified plan geometry was applied to the CT-of-the-day to evaluate the dosimetric effects of the virtual correction method. This virtual correction dosimetry was compared with calculated geometric and dosimetric results for an explicit 6DOF robotic couch correction methodology. A (2%, 2mm) gamma analysis comparing dose distributions created using the virtual corrections to those from explicit corrections showed that an average of 95.1% of all points had a gamma of 1 or less, with a standard deviation of 3.4%. For a total of 470 dosimetric metrics (ie,maximum and mean dose statistics for all relevant structures) compared for all 55 image-guidance sessions, the average dose difference for these metrics between the plans employing the virtual corrections and the explicit corrections was -0.12% with a standard deviation of 0.82%; 97.9% of all metrics were within 2%. Results showed that the virtual corrections yielded dosimetric distributions that were essentially equivalent to those obtained when 6DOF robotic corrections were used, and that always outperformed the most commonly employed clinical approach of 3 translations only. This suggests that for the patient datasets studied here, highly effective image-guidance corrections can be made without the use of a robotic couch.

Parametric investigation of geometric form effects on solar potential of housing units

Abstract The paper presents a study of the solar potential of different shapes of two-story single family housing units, located in mid-latitude climate. Seven plan geometries are studied: square, rectangle, trapezoid, L, U, H and T shapes. The study investigates the effect of these shapes on two major response variables – Solar radiation incident on equatorial-facing facades and transmitted by the fenestration of such facades, and electricity production potential of building integrated photovoltaic (BIPV) covering roof surfaces with optimal solar exposure. The parameters, whose effects on the response variables are investigated, include, in addition to the basic shapes and roof design, variations to the geometry of L and U shapes and variations to the roof design. Shape variations include varying values of the relative dimensions of shading and shaded facades and variations to the angle enclosed by the wings of these shapes. Variations of roof design consist of modifications to the tilt and side angles of hip roofs. The results indicate that the number of shading facades in-self shading geometries and their relative dimensions are the major parameters affecting solar incident and transmitted radiation. Manipulation of the orientation of wings in L shape units can result in increased peak electricity generation potential, and in shifting the timing of the peak by up to 2 h either side of solar noon. The shift of peak load may be economically beneficial, facilitating more even distribution of electricity production over an assemblage of buildings. Judicious manipulation of unit shapes and window location can lead to optimization of solar radiation and its utilization for electricity generation and passive solar gain.

City model enrichment

The combination of mobile communication technology with location and orientation aware digital cameras has introduced increasing interest in the exploitation of 3D city models for applications such as augmented reality and automated image captioning. The effectiveness of such applications is, at present, severely limited by the often poor quality of semantic annotation of the 3D models. In this paper, we show how freely available sources of georeferenced Web 2.0 information can be used for automated enrichment of 3D city models. Point referenced names of prominent buildings and landmarks mined from Wikipedia articles and from the OpenStreetMaps digital map and Geonames gazetteer have been matched to the 2D ground plan geometry of a 3D city model. In order to address the ambiguities that arise in the associations between these sources and the city model, we present procedures to merge potentially related buildings and implement fuzzy matching between reference points and building polygons. An experimental evaluation demonstrates the effectiveness of the presented methods.

Seismic response analysis of skew bridges with pounding deck–abutment joints

In this paper the seismic response of short skew bridges with deck–abutment pounding joints is revisited. The permanent deck rotations and transverse displacements of such bridges after the recent earthquake in Chile created an incentive to revisit their non-conventional behaviour. A novel non-smooth rigid body approach is proposed to analyze the seismic response of pounding skew bridges which involves oblique frictional multi-contact phenomena. The coupling of the response, due to contact, is analysed in depth. It is shown that the tendency of skew bridges to exhibit transverse displacements and/or rotate (and hence unseat) after deck–abutment collisions is not a factor of the skew angle alone, but rather of the plan geometry plus friction. This is expressed with proposed dimensionless criteria. The study also unveils that the coupling is more pronounced in the low range of the frequency spectrum (short-period excitations/flexible structures) and presents novel dimensionless response spectra for the transverse displacements and rotations, triggered by oblique contact in a skew bridge subsystem. Despite the complexity of the response, the proposed spectra highlight a clear pattern. The dimensionless rotations, arising from contact, decline as the ratio of the structural versus excitation frequency increases and become practically negligible in the upper range of the frequency spectrum. Finally, a pilot application to a typical skew bridge is presented.