Anchor Locations Research Articles

PVACview: an interactive visualization tool for efficient neoantigen prioritization and selection

BackgroundNeoantigen-targeting therapies including personalized vaccines have shown promise in the treatment of cancers, particularly when used in combination with checkpoint blockade therapy. At least 100 clinical trials involving these therapies have been initiated globally. Accurate identification and prioritization of neoantigens is crucial for designing these trials, predicting treatment response, and understanding mechanisms of resistance. With the advent of massively parallel DNA and RNA sequencing technologies, it is now possible to computationally predict neoantigens based on patient-specific variant information. However, numerous factors must be considered when prioritizing neoantigens for use in personalized therapies. Complexities such as alternative transcript annotations, various binding, presentation and immunogenicity prediction algorithms, and variable peptide lengths/registers all potentially impact the neoantigen selection process. There has been a rapid development of computational tools that attempt to account for these complexities. While these tools generate numerous algorithmic predictions for neoantigen characterization, results from these pipelines are difficult to navigate and require extensive knowledge of the underlying tools for accurate interpretation. This often leads to over-simplification of pipeline outputs to make them tractable, for example, limiting prediction to a single RNA isoform or only summarizing the top ranked of many possible peptide candidates. In addition to variant detection, gene expression, and predicted peptide binding affinities, recent studies have also demonstrated the importance of mutation location, allele-specific anchor locations, and variation of T-cell response to long versus short peptides. Due to the intricate nature and number of salient neoantigen features, presenting all relevant information to facilitate candidate selection for downstream applications is a difficult challenge that current tools fail to address.ResultsWe have created pVACview, the first interactive tool designed to aid in the prioritization and selection of neoantigen candidates for personalized neoantigen therapies including cancer vaccines. pVACview has a user-friendly and intuitive interface where users can upload, explore, select, and export their neoantigen candidates. The tool allows users to visualize candidates at multiple levels of detail including variant, transcript, peptide, and algorithm prediction information.ConclusionspVACview will allow researchers to analyze and prioritize neoantigen candidates with greater efficiency and accuracy in basic and translational settings. The application is available as part of the pVACtools software at pvactools.org and as an online server at pvacview.org.

How do implants overlying the spine influence “The Law of Diminishing Returns” in early-onset scoliosis patients?

PurposeThe “law of diminishing returns” (LODR) in early-onset scoliosis (EOS) is well-known. We hypothesized that previously observed variations between constructs may be related to the lateral distance that each construct lies from the spine. We therefore sought to determine whether the curve magnitude improvement and spinal length gains for distraction-based constructs in EOS are positively correlated with the collinearity of the spine and the convex-sided implant on posteroanterior radiographs.MethodsA prospectively-collected, multicenter EOS registry was queried for all patients who underwent non-fusion, distraction-based instrumentation surgery. Post-index radiographs were graded from 1 to 5 based on amount of overlap between the convex-sided rod and the apical vertebra. Grade 1: convex rod is lateral to convex-sided pedicle; Grade 2: overlaps the convex-sided pedicle; Grade 3: lies between pedicles; Grade 4: overlaps concave-sided pedicle; Grade 5: medial to concave-sided pedicle. ANOVA assessed the correlations between post-index overlap grade and change in (a) curve magnitude and (b) T1–T12 height. Multivariable regression modeling further assessed these associations.Results284 patients met all selection criteria and were included. On ANOVA, post-index grade was associated with curve magnitude (p <0.001) and T1-12 height (p = 0.028) change. Better curve correction and height change were associated with higher grade. On regression modeling, curve correction (R = 0.574) and T1–T12 height change (R = 0.339) remained significantly associated with grade when controlling for time, anchor locations, age, underlying diagnosis, and pre-index curve magnitude.ConclusionMore apical overlap by the convex rod was associated with better spinal deformity control and improved height gain.Level of Evidence IIITherapeutic.

Theoretical solutions for the anchoring force of 3‐D anchored slope and optimization strategy for anchoring force distribution

AbstractBased on the three‐dimensional limit equilibrium method with modifying normal stress over the slip surface, this study presents a theoretical solution for the anchoring force of three‐dimensional slopes and proposes a new optimization strategy for anchor force distribution. The method employed the Boussinesq solution from the field of elasticity. It led to the derivation of an equilibrium equation set, which incorporated the anchoring force increment. As a result, the approach yielded a more accurate theoretical value for a three‐dimensional anchoring force. In practical engineering applications, the prestress of anchor cables is often uniformly set, which may lead to discrepancies in the anchoring force requirements at different locations on the slope, potentially resulting in resource waste. The research introduces a linear programming approach to optimize resource allocation, aiming to minimize the total anchoring force under fixed anchor cable quantities, installation angles, and locations. Nevertheless, the results from the Simplex Method could lead to an overly concentrated distribution of anchoring force. Therefore, the study further employs the normal distribution theory to reallocate anchoring forces, thus achieving a more reasonable distribution. The proposed method has been validated through three example studies and a practical engineering case study, resulting in significant reductions in the total anchoring force following optimization. Moreover, such an approach allows for optimized handling of the anchoring force for each anchor cable. The work provides a new perspective and tool for practical engineering applications.

Anchors to Solid Clay Brick Masonry in Tension: Behavior under Monotonic and Repeated Loading for Constant Embedment Depth

This paper presents a part of an extensive experimental campaign performed at the National Technical University of Athens (NTUA) with the purpose of investigating the behavior of chemical anchors embedded in solid brick masonry. Anchors are tested in tension under monotonic or repeated loading. All tests are performed under displacement-controlled conditions. The experimental setup and the instrumentation are presented, along with the investigated parameters and the rationale for the selection of the values of those parameters. In this part of the experimental work, comprising fifty-six (56) tests, the examined parameters are the anchor locations (in mortar joints and in the center of bricks), the state of the substrate (cracked or uncracked), the width of the crack crossing the anchor or at its vicinity (up to 1.20 mm), as well as the loading history (monotonic or repeated). In the tests presented herein, the embedment length of the anchors is equal to 100 mm. The anchors are embedded in solid brick masonry wallettes, and subjected to a normal compressive stress equal to 0.20 MPa. The observed failure modes are explained, and the overall behavior of anchors subjected to tension is presented and commented upon, along with the effect of the investigated parameters on the measured tension resistance, and on the corresponding displacement.

MagicInput: Virtual Handwriting Interface Using Ubiquitous WiFi Signals

Past few years have witnessed the great potential of exploiting WiFi signals for positioning. Prior work focus on discovering the absolute locations of a radio source, and have achieved promising accuracies of tens of centimeters. However, many applications such as aerial gesture or handwriting tracking are more concerned with the detailed motion shape of the target rather than its exact locations, which require a several fold higher accuracy. To this end, we present MagicInput, a virtual handwriting interface by tracking the motion traces of a WiFi source. Based on Channel State Information (CSI), MagicInput elaborately devises an incremental motion-based tracking model by correlating the motion traces with the angle and length variations of propagation paths. The model shifts the tracking task from the transceiver view to the antenna array-oriented view, and eliminates the need for prior knowledge of anchor locations. MagicInput proposes an end-to-end pipeline for tracking refinement, by interference suppression, motion segmentation, and an integrated grasp pressure sensorbased motion instance detection. We prototype MagicInput using off-the-shelf WiFi radios, and extensive experiments attest that MagicInput can achieve the accuracy of 8.5 mm confronting diverse users and environment conditions. With ubiquitous WiFi signals, MagicInput can transform any region into an interactive handwriting interface with millimeter accuracy.

Computational prediction of MHC anchor locations guides neoantigen identification and prioritization.

Neoantigens are tumor-specific peptide sequences resulting from sources such as somatic DNA mutations. Upon loading onto major histocompatibility complex (MHC) molecules, they can trigger recognition by T cells. Accurate neoantigen identification is thus critical for both designing cancer vaccines and predicting response to immunotherapies. Neoantigen identification and prioritization relies on correctly predicting whether the presenting peptide sequence can successfully induce an immune response. Because most somatic mutations are single-nucleotide variants, changes between wild-type and mutated peptides are typically subtle and require cautious interpretation. A potentially underappreciated variable in neoantigen prediction pipelines is the mutation position within the peptide relative to its anchor positions for the patient's specific MHC molecules. Whereas a subset of peptide positions are presented to the T cell receptor for recognition, others are responsible for anchoring to the MHC, making these positional considerations critical for predicting T cell responses. We computationally predicted anchor positions for different peptide lengths for 328 common HLA alleles and identified unique anchoring patterns among them. Analysis of 923 tumor samples shows that 6 to 38% of neoantigen candidates are potentially misclassified and can be rescued using allele-specific knowledge of anchor positions. A subset of anchor results were orthogonally validated using protein crystallography structures. Representative anchor trends were experimentally validated using peptide-MHC stability assays and competition binding assays. By incorporating our anchor prediction results into neoantigen prediction pipelines, we hope to formalize, streamline, and improve the identification process for relevant clinical studies.

Received Signal Strength-Based Wireless Source Localization With Inaccurate Anchor Positions

Received signal strength (RSS)-based wireless localization is easy to implement at low cost. In practice, exact positions of anchors may not be available. This article focuses on determining the location of a source in the presence of inaccurate positions of anchors based on RSS directly. We first use Taylor expansion and a min–max approach to get a maximum likelihood estimator of the coordinates of the source. Then we propose a relaxed semidefinite programming model to circumvent the nonconvexity. We also propose a rounding algorithm considering both inaccurate source locations and inaccurate anchor locations. Simulation results together with analysis are presented to validate the proposed method.

Bankart Repair With Remplissage Restores Better Shoulder Stability Than Bankart Repair Alone, and Medial or Two Remplissage Anchors Increase Stability but Decrease Range of Motion: A Finite Element Analysis

To investigate the effects of the number and location of anchors for remplissage on postoperative glenohumeral biomechanics. A biomechanical study was conducted involving finite element model constructed based on data from the intact glenohumeral joint. Seven models were established, including a normal model, a model of Bankart lesion combined with "off-track" Hill-Sachs lesion, a model of Bankart repair alone, and 4 models of Bankart repair with remplissage based on different remplissage anchor numbers and locations. The effects of the number and location of the remplissage anchors on glenohumeral stability were studied through calculation and comparison of (1) the stress and its distribution on the joint capsule, cartilage, labrum and anchors as well as (2) the displacement of the humeral head. Finite element analysis demonstrated that contact stress on the glenohumeral cartilage decreased when medial or 2 anchors were used and was minimized in the combined repair model with 2 medial anchors. The stress on remplissage anchors was greater when the anchors were placed medially. The humeral head displacement was maximized in the combined lesion model. The combined repair models with 2 medially placed anchors showed the largest slope on the force-displacement curve, indicating the largest strain on the humeral head. Based on a finite element analysis, Bankart repair with remplissage restored better shoulder stability compared with Bankart repair alone in the treatment of anterior shoulder instability involving Bankart lesion combined with "off-track" Hill-Sachs lesion. When the anchor for remplissage was medially placed or 2 anchors were used, the stability of the glenohumeral joint increased but with a loss of range of motion. The results of this study will assist in choosing the number and location of anchors for remplissage during shoulder stabilization surgery although with some limitations.

Abstract 5639: Computational prediction of MHC anchor locations guide neoantigen prediction and prioritization

Abstract Neoantigens are novel peptide sequences resulting from somatic mutations in tumors that upon loading onto major histocompatibility complex (MHC) molecules allow recognition by T cells. Accurate neoantigen identification is thus critical for designing cancer vaccines and predicting response to immunotherapies. Neoantigen identification and prioritization relies on correctly inferring whether the presenting peptide sequence can successfully induce an immune response. As the majority of somatic mutations are SNVs, changes between wildtype and mutant peptide are subtle and require cautious interpretation. An important, yet underappreciated, variable in neoantigen-prediction pipelines is the mutation position within the peptide relative to its anchor positions for the patient’s specific HLA alleles. While a subset of peptide positions are presented to the T-cell receptor for recognition, others are responsible for anchoring to the MHC, making these positional considerations critical for predicting T-cell responses. However, a systematic method for determining anchor locations for the wide range of HLA alleles present in the population and application of these to evaluate MT/WT peptide pairs arising in tumors has not been reported. As a result, many neoantigen studies have either failed to adequately consider this crucial factor or have used conventional assumptions to guide their neoantigen identification process. Here, we provide a computational workflow for predicting anchor locations for a wide range of HLA alleles, using a reference dataset generated from clinical and The Cancer Genome Atlas (TCGA) patient samples. We calculated high probability anchor positions for different peptide lengths for over 300 common HLA alleles. Analysis of these results showed clusters of different anchor trends among the HLA alleles analyzed. A subset of these HLA anchor results were orthogonally validated using protein crystallography structures. Analysis of 923 tumor samples showed that 7-41% of neoantigen candidates were potentially misclassified in the neoantigen selection process and can be rescued using allele-specific knowledge of anchor positions. These anchor predictions are currently undergoing experimental validation using both peptide-MHC stability assays as well as fluorescence-based competition binding assays. By incorporating our anchor prediction results into neoantigen prediction pipelines, such as pVACtools, we hope to formalize and streamline the identification process for relevant clinical studies. Citation Format: Huiming Xia, Joshua McMichael, Michelle Becker-Hapak, Onyinyechi C. Onyeador, Rico Buchli, Ethan McClain, Patrick Pence, Suangson Supabphol, Megan M. Richters, Anamika Basu, Cody A. Ramirez, Cristina Puig-Saus, Kelsy C. Cotto, Jasreet Hundal, Susanna Kiwala, S. Peter Goedegebuure, Tanner M. Johanns, Gavin P. Dunn, Antoni Ribas, Christopher A. Miller, William Gillanders, Todd A. Fehniger, Obi L. Griffith, Malachi Griffith. Computational prediction of MHC anchor locations guide neoantigen prediction and prioritization [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5639.

Abstract 5036: pVACview: An integrative visualization tool for efficient neoantigen prioritization and selection

Abstract Neoantigen vaccines have demonstrated strong efficacy in the treatment of cancers in the realm of personalized medicine when used in combination with checkpoint blockade therapy. Numerous clinical trials involving these therapies are underway across the world. Accurate identification and prioritization of neoantigens is highly relevant to the design of these trials, and for predicting treatment response and understanding mechanisms of resistance. With the advent of whole exome and RNA sequencing technologies, researchers and clinicians are now able to computationally predict neoantigens and design personalized vaccines based on patient-specific mutation information. However, numerous factors must be considered when prioritizing neoantigens for use in personalized medicine, including somatic variant identification and expression, peptide processing and transportation, peptide-MHC binding and stability, recognition by cytotoxic T cells, etc. There has been a rapid development of computational tools that attempt to account for these complexities. Pipelines have been developed to allow researchers to run an ensemble of many potentially informative tools for individual patients. However, output results from these complex pipelines are often unorganized, difficult to navigate and require extensive knowledge of the underlying tools for accurate interpretation. Additionally, while current pipelines analyze neoantigens from the perspective of variants, transcripts and peptides, they fail to present the underlying details for efficient prioritization of the candidates. In addition to variant detection, gene expression and predicted peptide binding affinities, recent studies have also shown the importance of mutation location, allele-specific anchor locations, and variation of T-cell response to long versus short peptides. Due to the intricate nature of neoantigen features, presenting all relevant information to experimentalists and immunogenomics tumor boards for candidate selection is a difficult challenge. In response, we have created pVACview, an interactive tool designed to aid in the prioritization and selections of neoantigen candidates for personalized cancer vaccines. pVACview has a user-friendly and intuitive interface where users can upload, explore, select and export their neoantigen candidates. The tool allows users to visualize neoantigen candidates across three different levels, including variant, transcript and peptide level information. We hope pVACview will allow researchers and clinicians to analyze and prioritize neoantigen candidates with greater efficiency and accuracy. The application is available as part of the pVACtools pipeline at https://github.com/griffithlab/pVACtools and the online server can be accessed at pvacview.org. Citation Format: Huiming Xia, Susanna Kiwala, Zachary L. Skidmore, Bryan Fisk, S. Peter Goedegebuure, Christopher A. Miller, William E. Gillanders, Obi L. Griffith, Malachi Griffith. pVACview: An integrative visualization tool for efficient neoantigen prioritization and selection [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5036.

Parameter Estimation and Tracking of an Expandable Cable-Driven Parallel Mechanism for Minimally Invasive Interventions

Conventional catheter-based procedures suffer from inaccurate device steering, and navigation limitations as the long and flexible devices are manipulated remotely from outside the patient body. A recently developed approach aims to overcome these limitations by using an expandable cable-driven parallel mechanism for local device manipulation and tracking relative to the anatomy. However, as the frame of this system is flexible and may be constrained by unknown anatomical constraints inside the patient body, accurate system identification is a key and critical step which would ultimately determine the accuracy in device steering and tracking. In this paper, we present an optimization approach to identify the parameters of an expandable cable-driven parallel mechanism deployed in an unknown environment, merely based on measurements of the cable length variations that would be available outside the patient body. We have verified and validated the proposed approach in terms of accuracy in the prediction of the frame shape and cable anchor locations, as well as its tracking accuracy. Both simulations and experimental studies have been performed, and we have demonstrated that the proposed method allows for rapid frame shape and anchor position estimation with unknown anatomical constraints and permits localized device tracking and steering with submillimeter accuracy.

A Tool for Organizing Key Characteristics of Virtual, Augmented, and Mixed Reality for Human–Robot Interaction Systems: Synthesizing VAM-HRI Trends and Takeaways

Frameworks have begun to emerge to categorize Virtual, Augmented, and Mixed Reality (VAM) technologies that provide immersive, intuitive interfaces to facilitate Human-Robot Interaction. These frameworks, however, fail to capture key characteristics of the growing subfield of VAM-HRI and can be difficult to consistently apply due to continuous scales. This work builds upon these prior frameworks through the creation of a Tool for Organizing Key Characteristics of VAM-HRI Systems (TOKCS). TOKCS discretizes the continuous scales used within prior works for more consistent classification and adds additional characteristics related to a robot's internal model, anchor locations, manipulability, and the system's software and hardware. To showcase the tool's capability, TOKCS is applied to the ten papers from the fourth VAM-HRI workshop and examined for key trends and takeaways. These trends highlight the expressive capability of TOKCS while also helping frame newer trends and future work recommendations for VAM-HRI research.

Measuring joint space-time accessibility in transit network under travel time uncertainty

In densely populated areas, joint activity participation such as shopping and eating outside represents a substantial portion of individuals' daily activity-travel patterns. Individuals have several considerations in making joint activity choice behaviour such as space-time coordination, activity start time, activity location and joint activity duration. In a congested transit network, the travel time uncertainty significantly affects individuals' activity and travel choice behaviour. To conduct some important joint activities, individuals normally have high expectations of on-time arrival. Thus, the measurement of space-time accessibility in transportation networks should be extended to consider joint activity choices and travel time uncertainty. In this paper, a new method for measuring space-time accessibility is proposed for individuals' joint activities in transit network with consideration of travel time uncertainty. A reliable alighting location model is proposed to identify all feasible alighting locations in transit network to perform joint activities by explicitly considering constraints of on-time arrival probabilities. Individuals’ joint space-time accessibility (JSTA) is measured based on reliable alighting locations, travel time budget, and points of interests. Massive smart card data from metro network in Nanjing, China are used to show the merits of the proposed JSTA measure. The results show that there is a significant difference between the space-time accessibility to independent activity and that to joint activity under various on-time arrival probabilities. The effects of spatial (de)concentration of anchor locations and minimum joint activity duration on JSTA, and the role of additional participants are also presented in various scenarios. The proposed JSTA measure can be used to help policy makers to evaluate transit network development and land use planning in urban areas.

Impact of Anchor Location on Mitral Neochordae Forces: An In Vitro Study

PurposeThis study examined changes in force distribution between the neochordae corresponding to different ventricular anchor locations. DescriptionSeven porcine mitral valves were mounted in a left heart simulator. Neochordae (expanded polytetrafluoroethylene) originated from either a simulated left ventricular apex, papillary muscle base, or papillary muscle tip location. The neochordae were attached at three sites along the P2 leaflet segment: P2Lateral; P2Center, and P2Medial. Mitral regurgitation was induced by cutting posterior leaflet P2 marginal chordae. The forces on each neochord required to restore normal mitral valve coaptation were quantified for different ventricular anchoring origins and leaflet insertion sites. EvaluationThe results showed that under both normotensive and hypertensive conditions, the force exerted was much higher at P2Center than either P2Lateral or P2Medial, independent of ventricular anchor location. Also, forces on both P2Lateral and P2Medial were not statistically different. ConclusionsArtificial neochordae treatment for all anchoring locations was effective in correcting induced mitral regurgitation. The P2 central neochordae had a significantly higher force than both lateral neochords under all conditions.

Bone Volumes and Trajectory Angles for Acetabular Anchor Placement Can Be Optimized

PurposeThe purpose of this study was to determine the optimal anchor placement and trajectory when repairing acetabular labral tears during hip arthroscopy with the primary focus on the 12 to 3 o’clock positions on the acetabular rim.MethodsThree-dimensional computational models of the pelvis were generated from 13 cadaveric specimens using 3D slicer medical imaging software. A set of cones, consistent with the dimensions of a commonly used sutured anchor, were virtually embedded into the models at the 12, 1, 2, and 3 o’clock positions around the acetabulum. Mirror images of the cone were extended toward the superficial aspect of the hip. The volume of bone occupied by the virtual anchor, the trajectory angle, and the volume of overlap between adjacent anchor locations were calculated.ResultsBone volume was significantly greater at the 1 o’clock position (4196.2 [1190.2] mm3) compared with all other positions (P < .001). The 3 o’clock position had the smallest volume (629.2 [180.0] mm3) and was also significantly less than the 12 (P < .001) and 2 o’clock (P = .014) positions). The trajectory angle of 32.04 [5.05]°) at the 1 o’clock position was significantly greater compared with all other positions (P < .001). The least amount of adjacent position overlap occurred between the 2 and 3 o’clock positions (.12 [.42] mm3), and this was statistically smaller than the overlap between cones at the 12 and 1 o’clock positions (214.28 [251.88] mm3; P = .029) and the 1 and 2 o’clock positions (139.51 [177.14] mm3; P = .044).ConclusionsTrajectory angles and the thickness of bone around the acetabulum were the greatest at the 12 to 1 o’clock positions, with the 1 o’clock position identified as that with the largest trajectory angle for safe anchor insertion.Clinical RelevanceThe use of a single, workhorse portal, for anchor insertion may not be recommended and careful selection of a portal allowing a direct approach should be used for anterior anchor insertion.

Evaluation of static belt fit and belt torso contact for children on belt-positioning booster seats

Objective: Previous studies have indicated that gap between the seatbelt and torso (reduced belt torso contact) for children on belt-positioning booster seats (BPBs) may lead to less torso engagement and increased likelihood of shoulder belt slip-off during evasive vehicle maneuvers, potentially increasing injury risk during crashes. However, current BPB belt fit measures do not quantify belt gap and may not be able to fully discriminate between designs which provide good vs. poor dynamic outcomes. The goal of this study was to evaluate both novel (belt gap characteristics) and conventional measures of seatbelt fit for BPB-seated children. Methods: Ten BPBs and three seatbelt anchor locations were investigated. Fifty volunteers (4-14 years) were recruited and each evaluated on six unique combinations of BPB and seatbelt anchor location on a vehicle rear seat in a laboratory setting. A 3 D coordinate measurement system quantified positions of anatomic, seatbelt, BPB, and vehicle reference points. Novel belt gap (gap size, length, location, and percent torso contact) and conventional belt fit (position of belt on shoulder and pelvis) metrics were calculated using anatomic and seatbelt landmarks. Variation in belt fit and belt gap outcomes due to BPB, seatbelt anchor location, and anthropometry were investigated. Results: BPBs produced significantly different outcomes, while seatbelt anchor location did not. BPBs with features that directly routed the lower portion of the shoulder belt more forward on the buckle side produced the largest (29.3 ± 12.6 mm) and longest (106.9 ± 68.2 mm) belt gap on average, while BPBs that pulled the belt less forward or did not directly route the belt produced the smallest (13.9 ± 6.7 mm) and shortest (16.9 ± 33.9 mm) gap on average. Belt gap outcomes were not strongly correlated with conventional belt fit metrics, indicating that evaluation of belt gap may provide additional insight when attempting to discriminate between BPBs which provide good vs. poor seatbelt engagement during vehicle maneuvers and crashes. Conclusions: This is the first study to evaluate belt gap characteristics for BPB-seated children. Results suggest that belt fit and belt gap are influenced by BPB design, particularly lower shoulder belt routings, and may have implications for belt engagement during dynamic events.

Position Information From Reflecting Surfaces

In the context of positioning an agent with a single-anchor, this contribution focuses on the Fisher information about the position, orientation and clock offset of the agent provided by single-bounce reflections. The availability of prior knowledge of the agent's environment is taken into account via a prior distribution of the position of virtual anchors, and the rank, intensity and direction of provided information is studied. We show that when no prior knowledge is available, single-bounce reflections offer position information in the direction parallel to the reflecting surface, irrespective of the agent's and anchor's locations. We provide a geometrically intuitive explanation of the results and present numerical examples demonstrating their potential implications.

Optimum design of multi-anchored larssen type sheet pile wall for temporary construction works

In some construction works such as multi-basement buildings, subways, deep excavation problems are encountered. In such cases, the shoring walls are used to to prevent damage to the structures next to the excavation area and to provide a safe working environment in the excavation area. In cases where a temporary excavation support is required, sheet pile walls can be more economical comparing to the other walls in the long run due to their reusability. In the present study the analyses were carried out by changing various parametric components such as the number of anchors in vertical row, horizontal and vertical spacing amongst the anchors, anchor angle and excavation depth in LARSSEN type sheet piles constructed temporarily in medium-dense sand. In the analyses, the trapezoidal horizontal earth pressure envelope recommended by FHWA (1999) since the stress concentration occured at the anchor locations. Besides the limit values recommended by FHWA (1999) and BS (1989) was used in the analyses. In total 35488 different sheet pile wall geometry configurations were investigated. According to research results, the lowest costs occur when the horizontal spacing amongst the anchors is 3 m and the angle of the anchors with the horizontal is 150. The lowest costs were obtained when the vertical distance of the uppermost anchor to the ground surface is 3 m. Sheet pile sections with optimum cost were modeled in Plaxis 2D to run displacement analyses. Findings showed that the wall displacements were within the allowable limits commonly used in the literature.

Automated Positioning of Anchors for Personal Fall Arrest Systems for Steep-Sloped Roofs

Falls account for about one-third of all construction fatalities with most fatalities in the roofing trade. Even though a personal fall arrest system (PFAS) is required for fall protection, proper placement of PFAS anchor points is an issue evidenced by the high number of fatalities caused by incorrect anchor positioning. The research goal was to proof the concept of optimizing the location of the PFAS anchor points on steep-sloped roofs. This goal was achieved by: (1) Developing an algorithm for converting the required local jurisdiction construction regulations and standards for PFAS anchor positioning into machine-readable rules; and (2) Developing and validating an algorithm for optimizing the location of PFAS anchor points. The K-Nearest Neighbor Search (KNNS) optimization algorithm was selected in this research and was implemented into a standalone computer tool using Python programming language. The tool calculates the potential anchor locations that satisfy the fall clearance and swing hazard requirements and then displays the anchor locations both graphically and numerically. The optimization algorithm was validated using the K-fold Cross-Validation method, which proved the algorithm was adequately accurate and consistent. The research contribution is the proof of the concept that the development of an optimization algorithm and automated field-level tool for optimal selection of PFAS anchor points is possible, further research and refinement could help steep-sloped roofing companies improve their safety practices.

Racial/ethnic and class segregation at workplace and residence: A Los Angeles case study

ABSTRACT Expanding the scope of existing segregation literature, this research compares racial/ethnic segregation across economic classes and class segregation across racial/ethnic groups at two anchor locations of individual life: residence and workplace. Using the 2015 U.S. Longitudinal Employer-Household Dynamics data for the Los Angeles region, we depict a complicated picture: Segregation is moderate in the study area, but minority and/or low-income workers experience additional segregation on top of racial/ethnic segregation at residence. Specifically, the levels of segregation at residence are positively correlated with the segregation levels at workplace; racial/ethnic segregation is more severe at residence, while class segregation is more severe at the workplace, particularly for racial minorities; racial/ethnic segregation is the highest in the low-income group but lowest in the low-medium income group; class segregation in White workers is lower than that in Black and Asian workers at workplace but greater at residence. Therefore, policies that aim to effectively mitigate segregation should leverage intricate social environments at different spatial settings.