Vertical Deviation Research Articles

Ispitivanje uticaja broja orijentacionih tačaka na geometrijsku tačnost UAV fotogrametrijskih proizvoda formiranih pomoću pristupa strukture iz pokreta

The positional and vertical accuracy of UAV aerial photogrammetry products generated using the Structure from Motion (SfM) approach depends on various factors, such as flight plan parameters, camera quality, camera calibration, the SfM algorithm used, and the georeferencing process. The influence of the quantity of Ground Control Points (GCPs) on the geometric quality of generated models and the stability of camera calibration parameters assessed through self-calibration in the block-aerotriangulation process was investigated in this study. Three software systems were used to process the collected UAV photogrammetry images: Pix4D Mapper, Agisoft Metashape, and Trimble Inpho UASMaster. Standard statistical quality assessments were employed to assess the accuracy of the block-aerotriangulation. The research findings indicate that augmenting the quantity of GCPs enhances model reliability and decreases the RMSE values of vertical deviation on the control points. The RMSE values of vertical deviation on the check points for all three used software systems converged to approximately twice the value of the average spatial resolution. Additionally, the RMSE values of positional deviation on check points converged to the value of the average spatial resolution.

Alterations in Cortical Thickness in Children with Congenital Strabismus and Dissociated Vertical Deviation

Introduction: Little is known about the morphometric changes that occur in the cerebral cortex of children with congenital strabismus and Dissociated Vertical Deviation (DVD). Mathematical morphology provides the opportunity to discover alterations in cortical thickness. Objective: Identify and measure differences in cortical thickness in children with congenital strabismus and DVD. Materials and Methods: Twenty-two MRI brain studies were conducted, each comprising 120 sagittal slices of 1 mm. A cohort of 11 healthy children formed the control group, and a cohort of 11 children with congenital strabismus and Dissociated Vertical Deviation, both in Dissociated Esotropia and Dissociated Exotropia formed the case group. Differences in cortical thickness between both groups were compared and identified using the FreeSurfer suite. Subsequently, areas of interest were analyzed using the ImageJ program to determine density, area, size, and pixel quantity in these regions. Study results are presented through tables and figures. Results: Twelve inflated brain projections were obtained from 2640 MRI images. Thickness differences between both groups exhibited three areas with significant morphometric changes: the Left Angular Gyrus, Left Supramarginal Gyrus, and Right Pars Opercularis. Discussion: Children with congenital strabismus and DVD showed changes in cortical thickness that could be identified and measured through Voxel-Based Morphometry (VBM). It is plausible to consider that these changes are related to suppression, aiming to avoid diplopia.

Clinical Management of Vertical Hyperphoria and Photophobia Following Mild Traumatic Brain Injury: A Case Study

Following a mild TBI, symptoms of diplopia and photosensitivity are common. Findings such as a vertical deviation, may contribute to exasperating symptoms. Treatment of vertical deviations may cause hesitation for the provider as there is not a consensus in relation to prescribing vertical prism amounts. In regards to photosensitivity, fortunately most diminishes in intensity over the first couple of months following injury. Further treatment, including tints and sunglasses, improves patient comfort.

No-split, no-tenotomy transposition of only the superior rectus muscle combined with medial rectus recession in patients with complete abducens nerve palsy

To evaluate the outcomes of no-split, no-tenotomy transposition of only the superior rectus muscle combined with medial rectus recession in patients with complete abducens nerve palsy. In this procedure, the temporal margin of the superior rectus muscle, 10 mm posterior to the insertion, was secured with a nonabsorbable suture and sutured to the sclera at a distance of 12 mm from the limbus in the superotemporal quadrant, halfway between the superior rectus and lateral rectus. Success was defined as distance and near alignment of ≤8Δ and no diplopia in primary position 6 months after surgery. A total of 8 patients with abducens nerve palsy underwent the procedure. At the last follow-up, the mean postoperative change in primary position deviation was 42.6Δ ± 8.1Δ (range,34Δ-57Δ) for distance and 42.1Δ ± 7.5Δ (35Δ -57Δ) for near, a significant reduction (P = 0.012). Abduction deficit also improved significantly (P = 0.010). Postoperatively, no vertical deviation or torsional diplopia was induced. At the 6 months' follow-up, compared with the first postoperative visit, an esodrift at near developed in 1 patient. Of the 8 cases, 6fulfilled the criteria for success. In our small study cohort, no-split, no-tenotomy superior rectus transposition and medial rectus recession improved esotropia and abduction limitation without inducing significant vertical deviations or torsional diplopia.

EVALUATION OF THE DYNAMICS OF ELASTIC PLATE AND LIQUID SECTION DYNAMIC ABSORBER

In this paper, the problem of studying the dynamics of transverse vibrations of plate, taking into account the elastic dissipative characteristics of the hysteresis type in conjunction with a liquid section dynamic absorber under the influence of kinematic excitations. In the differential equations of motion, the elastic dissipative characteristics of the plate material of the hysteresis type are taken into account by means of harmonic linearization coefficients based on the Pisarenko - Boginich hypothesis. The amplitude-frequency characteristic of the vibrating plate and the analytical expressions of the transfer function were determined using a differential operator from a system of differential equations of motion depending on the system parameters. In order to perform numerical calculations, the coefficients of the first three terms of the logarithmic decrement expression were found. In the amplitude interval, the function representing the vertical deviation of the amplitude-frequency characteristic decreases and the function representing the energy dissipation in the plate material increases. It has been shown that the efficiency of the liquid section dynamic absorber in quenching harmful plate vibrations at low frequencies can be evaluated based on the results of numerical calculations to ensure that the displacements of the plate point reach minimum values. Amplitude-frequency characteristics for plate points at different parameters were constructed for the distributed parametric system using the developed model and method. Recommendations for the selection of parameters of the system depending on the elastic dissipative and inertial properties are given.

Does the fixture thread depth affect the accuracy of implant placement during fully guided immediate implant placement?: A human cadaver study.

The fixture thread depth reportedly influences the primary stability of dental implant, but its effect on the positional accuracy in immediate implant placement has not been reported previously. Fifty-six single-rooted, anterior and premolar teeth were extracted from six human cadavers, followed by installing either regular-threaded implants (RT group, N=30) or deep-threaded implants (DT group, N=26) completely relying on the surgical guide. Optical impressions taken after osteotomy and fixture installation were superimposed with the preoperative virtual planning data to measure the vertical, angular, platform and apex deviations that occurred during osteotomy and installation. While the osteotomy deviations were similar between the two groups, the angular and apex deviation of the DT group (2.67 ± 2.56°; 1.04 ± 0.49 mm, respectively) were significantly larger than those of the RT group (1.61 ± 1.04°; 0.67 ± 0.41 mm, respectively) during installation (p < .05). When the installation deviations were analysed in the anterior and premolar areas separately, the angular, platform and apex deviations of the DT group (3.05 ± 3.26°; 0.75 ± 0.32 mm; 1.08 ± 0.56 mm, respectively) were significantly larger than those of the RT group (1.56 ± 0.73°, 0.59 ± 0.28 mm; 0.62 ± 0.38 mm, respectively) in the anterior site (p < .05), whereas there was no significant intergroup difference in the premolar site. In immediate-implant surgery, using an implant with a deeper thread might increase the deviations during installation, especially in the anterior area.

Study on the Variation of Vertical Attitude Deviation for Long-Distance Jacking with an Initial Slope of Super-Large Frame Box Culvert

Study on the Variation of Vertical Attitude Deviation for Long-Distance Jacking with an Initial Slope of Super-Large Frame Box Culvert

Torsional strabismus and vertical rectus muscle surgery in thyroid eye disease

To assess the torsional component in patients with vertical strabismus due to thyroid eye disease (TED) and its course after vertical rectus muscle surgery. Retrospective chart review of patients undergoing vertical strabismus surgery for TED between 1998 and 2017, having undergone pre- and postoperative Harms tangent screen examination. Forty patients (27 women) were identified. A torsional component was present in all patients. Thirty-three patients had a mean excyclotorsion of 4.5° in primary position, increasing to 8.2° in upgaze, associated with restricted elevation. Inferior rectus muscle recession (n=29) reduced the excyclotorsion in all cases. A 4.4° mean incyclotorsion was present in primary position in 7 cases, increasing to 7.1° in downgaze. Superior rectus muscle recession reduced the incyclotorsion in 5/6 cases. The torsional surgical dose-effect relationship was correlated with the amount of preoperative torsion. The field of binocular single vision improved from 6.5% preoperatively to 71.1% after surgery. Ocular torsion is common in vertical strabismus secondary to TED and is significantly improved by vertical rectus muscle surgery alone. Surgery should be planned according to vertical deviation and motility limitation, and vertical rectus muscles surgery should be considered the first line of treatment, with selective oblique muscle surgery as a second-line option, which was unnecessary in our series.

Performance of Integrated Ground-Air-Space FSO Links Over Various Turbulent Environments

We analyze the outage probability of integrated ground-air-space free-space optical (FSO) communication links for different atmospheric turbulence channel models. The performance of ground to high altitude platforms (HAPS), HAPS to geostationay Earth orbit (GEO) satellite, HAPS to HAPS and ground to GEO satellite is investigated for various link configurations (downlink, horizontal, and uplink) and parameters such as zenith angle, channel state, horizontal and vertical deviations, altitude, beam waist, receiver aperture diameter, wind speed, and visibility. The atmospheric attenuation (the effects of fog, cloud and volcanic activities), atmospheric turbulence, angle of arrival (AOA) fluctuations and pointing error are included in the considered model. Closed-form expressions for the probability density function (PDF) and cumulative distribution function (CDF) are obtained for Lognormal, Gamma and exponentiated Weibull distributed channel models. The benefit of using HAPS is shown by comparison of outage probabilities for direct ground to GEO satellite and HAPS assisted ground to GEO satellite links.

Accuracy of dynamic implant navigation surgery performed by a novice operator.

The main objective was to evaluate the accuracy of dynamic navigation-guided surgery (DNGS) for implant positioning performed by a novice operator. The secondary objectives were to analyze the operator's learning curve and identify possible complications deriving from the technique. Twenty-five implants were placed in eight partially edentulous human heads. Preoperative CBCT scans were imported to planning software to determine the implant positions. Implants were placed using a dynamic navigation system. Postoperative CBCTs were superimposed onto the implant planning images. Discrepancies between the virtually planned implant positions and the postoperative positions were evaluated by measuring horizontal platform deviation, apex deviation, apicocoronal (vertical) deviation, and angular deviation. Mean platform, apex, vertical, and angle deviations were 1.55 ± 0.81 mm, 2.45 ± 0.84 mm, 1.59 ± 0.70 mm, and 5.56 ± 4.03 degrees, respectively. No significant differences were found between the maxilla and mandible or between anterior and posterior sites. A flat learning curve was observed, with the exception of the implant platform, where a tendency toward improvement in accuracy was observed between the 8th and the 17th implant placed. No complications were reported. Based on the results of a study performed by a novice operator on a cadaveric model, DNGS allows accurate implant placement within a 2-mm safety margin in terms of implant platform and vertical positions, and a 3-mm margin in apical vicinities. The technique requires practice to learn the required eye-hand coordination. (Int J Comput Dent 2022;25(4):377-0; doi: 10.3290/j.ijcd.b2588207).

Postoperative drift and dose-response of strabismus surgery in thyroid eye disease: predicting desired outcomes with intraoperative adjustable sutures

ObjectifPrésenter les résultats de la correction chirurgicale du strabisme secondaire à l'ophtalmopathie thyroïdienne réalisée par l'insertion de sutures de type « nœud papillon » (bow-knot) ajustables en cours de chirurgie sous anesthésie locale et concevoir des modèles de prédiction de la correction chirurgicale et de la déviation postopératoire en fonction de la relation dose-effet de l'intervention. MéthodesNous avons procédé à une analyse rétrospective des dossiers de patients opérés entre 2016 et 2021. Le résultat était jugé satisfaisant si la diplopie avait disparu et s'accompagnait d'un alignement vertical (< 5 DP) et horizontal (< 10 DP) stable en position primaire du regard. La correction de la diplopie subjective au moyen de prismes permettant un alignement moteur était considérée comme un résultat passable. Dans les autres cas, le résultat était jugé médiocre. RésultatsAu total, 73 patients ont été admis à cette étude (60 femmes, soit 82 %). Les déviations horizontales et verticales moyennes en période préopératoire se chiffraient à 26,9 DP (é.-t. : 19,1) et à 11,8 DP (é.-t. : 7,6), respectivement. La déviation horizontale moyenne était de –3,2 DP (é.-t. : 5,2), tandis que la déviation verticale moyenne était de –3,4 DP (é.-t. : 3,3). Une analyse de régression linéaire a permis d’établir une relation dose-effet de 2,37 DP/mm pour la récession du droit médial (p < 0,0001; r2 = 0,777) et de 3,75 DP/mm pour la récession unilatérale du droit inférieur (p < 0,0001; r2 = 0,922). Les taux de réussite se déclinaient comme suit : satisfaisant chez 62 patients (85 %), passable chez 7 patients (10 %) et médiocre chez 4 patients (5 %). ConclusionsLa récession musculaire réalisée au moyen de sutures ajustables pendant l'intervention est une technique efficace pour corriger le strabisme secondaire à l'ophtalmopathie thyroïdienne. Il est possible d'obtenir une relation dose-effet prévisible avec une tendance vers une surcorrection. Une sous-correction proportionnelle à l'ampleur de la chirurgie prévue devrait être la cible de choix en période postopératoire immédiate. On n'a pas pu établir de corrélation entre d'autres variables, notamment la décompression orbitaire et la chirurgie à la fois verticale et horizontale, et la relation dose-effet ou la déviation postopératoire. Cela dit, d'autres études devront être réalisées afin de valider nos résultats.

Physiotherapy as a Specific and Purposeful Form of Physical Activity in Children with Idiopathic Body Asymmetry.

The aim of the study was to determine the relationship between idiopathic asymmetry in infants and body posture in children at an early school age. The study included 45 girls aged nine. The Diers Formetric III 4D device was used to assess body posture, which allows photogrammetric registration of the back surface using the raster stereography process. For the purposes of the re-search project, the examination was performed via DiCAM using the "Average measurement" mode. Despite physiotherapy, these children had more postural defects later on compared to the control group due to asymmetry. They mainly concerned pelvic skewness, scoliosis angle, deviation from the vertical line and lateral deviation, as well as surface rotation. Positive correlations were observed between direction of asymmetry and pelvic skewness (r = 0.40), and between the location of asymmetry and the location of curvature (r = 0.39). Significant negative correlations were also found between the age of treatment initiation and trunk length (r = -0.42). There was also a negative correlation between the number of physiotherapeutic appointments and deviation from the vertical line, which means that along with an increase in the number of physiotherapeutic visits, the value of deviation from the vertical line decreased (p = -0.40). For scoliosis angle, the most important predictor was the direction of asymmetry (p = 0.05). For the location of the curvature, the most important predictor was the direction of asymmetry (p = 0.04), as well as the number of physiotherapeutic appointments (p = 0.04). Additionally, regression analysis allowed us to show that the number of physiotherapeutic visits (p = 0.03) was the most important predictor of curvature direction. The applied physiotherapy probably contributed to the occurrence of a smaller number of postural defects in these children at a later age. Physiotherapy as a specific and targeted form of physical activity among infants with idiopathic asymmetry should play a very important role in the prevention of body posture defects.

Reduction in Energy Consumption by Mitigation of Cultivation Resistance Due to the New Fallow Harrow Concept

One of the best precursors for winter wheat is fallow. Its application aims to solve two important tasks: preserving and accumulating soil moisture and weed control. The authors of this paper have designed a new modular harrow for fallow tillage, which can work stably at a depth of 5–6 cm tillage while maintaining and even accumulating soil moisture. This article describes a method designed by the authors for a reasonable selection of the design parameters concerning the working devices mounted inside the new harrow, such as their length and working width, as well as the angles of vertical inclination (ε) and horizontal deviation (γ) of blades, depending on the accepted depth of the upper soil layer loosening. To reduce the soil tillage resistance of the harrowing unit resulting in a reduction in the tractor fuel consumption, the value of the inclination angle (ε) of its vertical blade should be chosen so that the corresponding change in the value of the deflection angle of the horizontal blade (γ) complies with the constrain of the product of tangents of these angles. Moreover, preference should be given to choosing the value of the angle ε with the subsequent determination of the angle γ value. It is demonstrated that proper use of the new type of harrow assures fuel savings and decreases carbon dioxide emissions even if fossil fuel alone is used. Additional reduction of CO2 emission can be achieved when biofuels are used as a replacement for fossil ones.

Efficacy of inferior oblique belly transposition combined with inferior oblique recession for asymmetric inferior oblique overaction

ObjectifÉvaluer l'efficacité de la transposition du ventre de l'oblique inférieur (IOBT) associée à la récession de l'oblique inférieur (OI) pour la correction d'une hyperaction asymétrique bilatérale de l'oblique inférieur (IOOA). MéthodesAnalyse rétrospective des données de 14 patients qui ont subi une IOBT du côté où l'IOOA asymétrique bilatérale était légère et une récession de l'OI du côté où l'IOOA était grave. On a examiné les principaux résultats chirurgicaux obtenus, dont la correction de l'IOOA, de l'hypertropie, de la déviation horizontale, de l'incomitance V et de l'angle de l'axe disque optique-fovéa. RésultatsLa valeur préopératoire (+1,86 ± 0,53) de l'IOOA du côté le moins atteint est passée à +0,07 ± 0,27 (p < 0,001) après l'IOBT; du côté le plus atteint, l'IOOA est passée de +3,14 ± 0,53 à +0,14 ± 0,36 après la récession de l'OI (p < 0,001). La déviation verticale en position primaire en vision de loin est passée de 8,43 ± 4,05 DP à 1,21 ± 1,48 DP après l'intervention (p < 0,001). L'incomitance V moyenne se chiffrait à 25,00 ± 11,62 DP avant l'intervention et à 3,18 ± 2,18 DP après cette dernière (p < 0,001). L'angle de l'axe disque optique-fovéa moyen est passé de –10,47 ± 5,85 degrés à –7,82 ± 6,42 degrés (p = 0,023) du côté où a été réalisée l'IOBT, et de –11,05 ± 5,14 degrés à –6,09 ± 4,52 degrés (p = 0,001) du côté soumis à la récession de l'OI. Le taux de réussite global était de 71,4 % (10 patients sur 14). ConclusionsL'association d'une IOBT à une récession de l'OI est une technique efficace et sûre pour éliminer l'hypertropie, l'incomitance V et l'extorsion en présence d'IOOA asymétrique bilatérale.

Accuracy of guided dental implant surgery using a fully digital workflow: A case series

Statement of problemComputer-guided implant surgery facilitated by intraoral scanning may enhance the efficiency of the digital workflow. However, it is necessary to assess technique accuracy to evaluate the accuracy of implant placement. PurposeThe purpose of this clinical study was to evaluate the accuracy of a virtual computer-aided design and computer-aided manufacturing (CAD-CAM) static guided surgery technique associated with intraoral scanning in partially edentulous participants by analyzing the overlap among preoperative and postoperative cone beam computed tomography (CBCT) scans, virtual planning, and the guided surgery performed. Material and methodsEleven partially edentulous participants underwent CBCT and intraoral scanning (TRIOS3). Data were integrated into a software program (ImplantViewer 3.5) for the virtual planning of implants and 3-dimensional (3D) printing of the prototype CAD-CAM surgical guide. A total of 18 implants were placed using the CAD-CAM static computer-aided implant surgery technique (Strong SW). After 15 days, postoperative CBCT scans were made and 4 variables (angular, coronal, apical, and vertical deviation) were measured to compare the virtually planned implants and the implants placed by analyzing the overlap between preoperative and postoperative of the virtual planning and guided surgery performed using the ImplantViewer 3.5 and Rhino 6 software programs. ResultsDeviations were found in all parameters analyzed. The mean angular deviation was 2.68 ±1.62 degrees; mean coronal deviation, 0.82 ±0.44 mm; mean apical deviation, 1.14 ±0.44 mm; and mean vertical deviation, 0.62 ±0.44 mm. ConclusionsThe implants placed using the CAD-CAM static guided surgery technique associated with intraoral scanning in partially edentulous participants exhibited angular and linear deviations when compared with virtual planning implants. However, these deviations were not clinically significant.

Influence of artificial landmarks on the accuracy of complete arch scans in the partially edentulous maxilla: An in vitro study

Statement of problemScan path length and the presence of edentulous alveolar ridge sections have a negative influence on scanning accuracy. How different artificial landmarks combined with an adapted scanning method affect accuracy is unclear. PurposeThe purpose of this in vitro study was to determine the influence of 2 different artificial landmarks combined with an adapted scanning method on the scanning accuracy of a partially edentulous maxillary model. Material and methodsThe model simulated a maxilla with 6 prepared teeth to accommodate a complete arch fixed partial denture. Five ceramic precision balls (ball center P1–P5), distributed buccally to the dental arch, were used to detect the dimensional and angular changes between the reference model and the intraoral scans. One intraoral scanner (Primescan) was used to make 30 scans each with either the scanning strategy recommended by the manufacturer (M) or with an adapted scanning strategy and the use of a bar (B) or 4 plates (P) as artificial landmarks in the dorsal palate. Data were statistically analyzed using a generalized least squares regression model (α=.05). ResultsScanning with artificial landmarks reduced the maximum absolute distance deviations (M: 249 μm, B: 190 μm, P: 238 μm) and the maximum angle deviations (M: 0.31 degrees, B: 0.28 degrees, P: 0.26 degrees). Vertical distance deviations were improved by 10 to 50% with the use of artificial landmarks. Absolute mean distance deviations were significantly lower for group M (P<.001). In contrast, with artificial landmarks, mean angle (P<.001) and mean vertical distance deviations (P<.014) improved significantly. ConclusionsScanning with artificial landmarks in the dorsal palate combined with an adapted scanning method improved the scanning accuracy and reliability of vertical distance deviations.

Evaluation of Streamed Hardware-to-Software Telemedicine Strabismus Consultations Utilizing Video Glasses.

While video glasses have been shown to be an effective tool for real-time pediatric strabismus telemedicine consultations, the high cost of the hardware-to-hardware conferencing system and bandwidth limitations may present barriers to accessibility and widespread adoption. This study evaluates the use of video glasses with a more affordable hardware-to-software video conferencing system for real-time strabismus consultations across multiple graders. A pediatric ophthalmologist (Grader 1) wearing video glasses simultaneously performed and recorded strabismus examinations in primary gaze, with and without correction, both at distance and near. Recorded parameters included strabismus category, angle measurements, and ocular motility. Three years later, four pediatric ophthalmologists (Graders 1-4) reviewed and graded streamed video feed transmitted at 1 megabit per second (Mbps) from a hard-wired codec to software. Agreement between streamed and gold standard in-person findings was determined by weighted kappa (κ) for categorical variables, intraclass correlation coefficient (ICC) for continuous variables, and percent agreement. Eighteen patients aged 4-11 years (median, 7 years) were included. Agreement in strabismus category between in-person and streamed examinations was perfect for both horizontal and vertical deviations (κ=1.0). Almost perfect agreement was found for degree manifest (tropia vs intermittent tropia vs phoria) across graders (κ=0.91, range 0.86-0.97). Agreement for angle measurements was excellent across graders (ICC = 0.97, range 0.97-0.98). Extraocular motility agreement was 90% for all graders combined, with Grader 1 having 100% agreement between her in-person and streamed examinations. Feed obtained from video glasses streamed through a hardware-to-software video conferencing system at 1 Mbps is a reliable tool for pediatric strabismus telemedicine evaluations.

Comparison of verticality perception and postural sway induced by double temple-mastoidal and bipolar binaural 20 Hz sinusoidal galvanic vestibular stimulation.

Galvanic vestibular stimulation (GVS) is believed to be one of the most valuable tools for studying the vestibular system. In our opinion, its combined effect on posture and perception needs to be examined more. The present study was conducted to investigate the effect of a 20 Hz sinusoidal Galvanic Vestibular Stimulation (sGVS) on the body sway and subjective visual vertical (SVV) deviation through two sets of electrode montages (bipolar binaural and double temple-mastoidal stimulation) during a three-stage experiment (baseline, threshold, and supra-threshold levels). While the individuals (32 normal individuals, 10 males, the mean age of 25.37±3.00 years) were standing on a posturography device and SVV goggles were put on, the parameters of the body sway and SVV deviation were measured simultaneously. Following the baseline stage (measuring without stimulation), the parameters were investigated during the threshold and supra-threshold stages (1 mA above the threshold) for 20 seconds. This was done separately for each electrode montage. Then, the results were compared between the three experimental stages and the two electrode montages. In both electrode montages, "the maximum amplitude" of the mediolateral (ML) and anteroposterior (AP) body sway decreased and increased in the threshold and supra-threshold stages, respectively, compared to the baseline stage. Comparison of the amount of "amplitude change" caused by each electrode montages showed that the double temple-mastoidal stimulation induced a significantly greater amplitude change in body sway during both threshold and supra-threshold stages (relative to the baseline stage).The absolute mean values of the SVV deviation were significantly different between the baseline and supra-threshold levels in both electrode montages. The SVV deviation in double temple-mastoidal stimulation was a bit greater than that in the bipolar binaural stimulation. Double temple-mastoidal stimulation has induced greater amount of change in the body sway and SVV deviation. This may be due to the more effective stimulation of the otoliths than semicircular canals.

A TIME EFFICIENT QUALITY CHECK METHOD BASED ON LASER SCANNING FOR INSTALLATION OF PREFABRICATED WALL PANELS

Abstract. Verticality check of prefabricated elements is an essential part of prefabrication construction. Currently, it is mostly carried out by manual methods, which is slow and inefficient. Previous studies have used laser scanning for the quality check but mainly focused on surface defects, flatness, and the dimension of construction elements. Very few studies used laser scanning to evaluate the installation quality of prefabricated elements. Those, who adopted the laser scanning method, compared the as-built with the initial design version of BIM. Such approach requires an accurate design version of BIM with tedious manual tasks relying on human skills that involve errors. This on-going study investigates a verticality check method based on laser scanning for assessing the quality of wall panel installations without relying on previous drawings or BIM. The proposed method enables practitioners to confirm the quality of the wall panel installation and its vertical deviations based on the processed point cloud data. The region growing segmentation and random sample consensus are used to process the acquired data for computing the deviations. This method is validated in a real high-rise prefabrication residential building. Our method took about 9 min/100 m2, versus the conventional method, which took 31 min/100 m2. The experiments indicate that the proposed method is significantly more time-efficient compared to the conventional manual method. The contribution of this study includes suggesting suitable parameters for measuring the vertical dimensions of prefabricated wall panels and deviations that can be replicated in high-rise prefabricated residential projects.

Numerical simulation for deformation characteristic of tea shoot under negative pressure guidance by the immersed boundary–lattice Boltzmann method

At present, due to the shortage of tea picking labour force, realizing the mechanized picking of famous tea is urgent. Using negative pressure guidance is a feasible method, which can compensate the localization error of machine vision. In this paper, tea shoot with one bud and two leaves is taken as the study object, and a ‘Y-type’ tea physical model is established according to its physical properties. Moreover, the deformation characteristic of tea shoot under negative pressure guidance is studied by using the immersed boundary–lattice Boltzmann method. The purpose is to analyse the effects of pressure P inside the pipe, vertical deviation H and horizontal deviation W on the deformation characteristics of tea shoot quantitatively. The effectiveness of the numerical calculation method is verified by the negative pressure guiding test. The results show that the success rate of negative pressure guidance is 100% when the leaf span d ≤ 30 mm and the horizontal deviation W ≤ 10 mm. The useful data and insights into the picking technology of famous tea based on negative pressure guidance are provided in this paper according to the findings mentioned above.