Seat Position Research Articles

Evaluation of Ventilation Strategies to Mitigate Airborne Infection Risk in a Dental School: A Three-Dimensional CFD Analysis of Airflow Patterns and Ventilation Efficiency

Infection prevention and control is a crucial element in providing a safe environment for dental clinics and reducing airborne infections risks during dental procedures. In response to the prevailing COVID-19 situations, the clinical space in the dental school was operated with ventilation strategies, increasing air exchanges and incorporating supply and return air arrangement based on seating positions. This study evaluated airflow patterns to examine personal exposure to airborne infection risk under these strategies. The three-dimensional computational fluid dynamics technique using computational fluid dynamics (CFD) analysis was performed in 50 multi-units of the dental school of the university in Bangkok, Thailand. The results revealed substantial improvements in indoor ventilation. Improvement of airflow patterns and directions surpassed conventional design of the pre-existing building’s system and helped reduce airborne contaminant concentrations. The further discussion of occupant-based design in dental schools is needed to optimize ventilation systems and engineering controls concerning indoor airborne infections.

Evacuation from Cramped Interiors with Aisle Seats: Uncertainty Induced by the Random Choice of Initial Positions

Considering evacuation from cramped interiors with aisle seats, the initial seating positions of pedestrians represent a non-negligible source of variance in total evacuation time. By means of Pathfinder simulations, this uncertainty is quantitatively investigated for a train and lecture hall geometry with homogeneous and heterogeneous groups of agents. Furthermore, an energy-inspired description of the occupation configuration is introduced that enables a proper numerical representation of the configuration space of the initial seating positions.

Development of a feed-forward audio-visual notification system for reducing motion sickness in autonomous vehicles

To mitigate motion sickness occurring in seat positions where driving conditions cannot be predicted due to the changed interior structure of autonomous vehicles, a feed-forward audio-visual notification system was developed. The design, implemented in the driving environment, provides information through ambient light and notifying sound by predicting signal processing information, including steering angle and turn signals, to address the audio-visual impact of changes in the vehicle's direction, speed, and acceleration with feed-forward alerts. The correlation model between psychological and physiological responses was developed through measurements such as MSQ, MISC, EEG, fNIRS, and HRV during driving, quantifying the degree of motion sickness and improvement situations. The effect of visual variation by ambient light and the customized effect of notifying sound were combined to compare and analyze the degree of motion sickness reduction following the installation of the notification system.

Prone transpsoas lateral interbody fusion with retractor-mounted camera and heads-up display: illustrative case.

The prone transpsoas (PTP) technique involves the performance of a lateral lumbar interbody fusion with the patient prone. One challenge encountered in the early experience with the PTP technique is that with the patient in the prone position rather than the lateral decubitus position, the surgeon is often forced to raise the bed significantly and perform the interbody work in a hunched and seated position with their neck extended and shoulders abducted. The authors report on the use of a sterile retractor-mounted camera during PTP that allows for the surgery to be performed with surgical anatomy visualized on a heads-up display. The PTP procedure is performed without significant modification from standard practice. After the self-retaining retractor is inserted, a sterile retractor-mounted camera can be introduced down one of the blades of the self-retaining retractor, preferably the dorsally situated blade to avoid camera line-of-sight issues with dependent irrigation or bleeding. The surgical field can now be visualized on a high-definition monitor, allowing the surgeon to stand at the patient's side instead of sitting. A sterile retractor-mounted camera with a heads-up display is a novel way to address ergonomic challenges as well as improve educational opportunities in the operating room. https://thejns.org/doi/10.3171/CASE24318.

Pediatric occupant-to-occupant interaction responses in side impact conditions using Q-dummy and child human body models

Objective Road safety of children has improved considerably over the past decade; however, there is still much scope to better protect these occupants. Ensuring adequate protection of children seated in the rear seats requires a greater understanding of how children are injured in side crashes. The purpose of this study was to enhance the knowledge of children’s potential injuries in side impact collisions by the investigation of two different child sizes seated in different positions in the rear seats. The injury metrics associated with the occupant-to-occupant or occupant-to-child restraint system interaction was also identified. Methods Finite Elements Method simulations were performed using a validated simplified vehicle model with fully deformable side components. Dynamic virtual tests according to the Euro NCAP Child Occupant Protection Protocol were performed considering three different scenarios in terms of occupants´ distribution in the rear seats. Simulations were conducted with dummy and human body models. The injury metrics associated with near-side and far-side positions and the occupant-to-occupant interaction were analyzed. Results The 10-year-old child seated in the far-side position presented higher injury values, especially in the head due to the contact with the adjacent child or child restraint occupying the near-side seating position. Similar responses were observed in human body and dummies models in terms of head and neck injury values. However, human body models showed an increase in the chest measurements. Conclusions This study highlighted that the potential injuries of a child seated on the rear seats in a side impact crash are likely to be increased by the presence of an adjacent seat occupant, especially when larger children were seated in the far-side seating location or a CRS was installed in the near-side seating position. Results offer insight into the occupant-to-occupant interaction and occupants’ size as relevant factors to improve children safety under side impact conditions.

How attentive is a student in class? A concentration evaluation method based on head Euler angle

How attentive is a student in class? It is an interesting and challenging question in the field of education research. In this paper, a concentration evaluation method based on head Euler angle is proposed. First, a fine large-small-interval video sampling strategy is advocated and concepts of dynamic threshold and action amplitude coefficient are defined, which are fused together to get the head up rate. Second, head front-facing rate is computed through analyzing the yaw angle, which is obtained from a proposed spatial physical model of camera and student seat position. Third, for any given time period, class concentration of a student is derived by fusing and normalizing the head up rate and head front-facing rate based on Euclidean-distance. Finally, accuracy experiments are conducted, where the proposed method achieves an average accuracy of 89.8% compared with the average score from the questionnaire given by 22 reviewers. Also, robust experiments on several head pose estimation models are facilitated, which achieves an average accuracy of 98.43% on recorded video dataset, indicates insensitivity to the head pose estimation model used for data collection and verifies that the proposed method is independent on any specific head pose estimation model. The experimental results show that the proposed method is accurate, effective and robust for the concentration evaluation in class.

3D-ARM-Gaze: a public dataset of 3D Arm Reaching Movements with Gaze information in virtual reality

3D-ARM-Gaze is a public dataset designed to provide natural arm movements together with visual and gaze information when reaching objects in a wide reachable space from a precisely controlled, comfortably seated posture. Participants were involved in picking and placing objects in various positions and orientations in a virtual environment, whereby a specific procedure maximized the workspace explored while ensuring a consistent seated posture by guiding participants to a predetermined neutral posture via visual feedback from the trunk and shoulders. These experimental settings enabled to capture natural arm movements with high median success rates (>98% objects reached) and minimal compensatory movements. The dataset regroups more than 2.5 million samples recorded from 20 healthy participants performing 14 000 single pick-and-place movements (700 per participant). While initially designed to explore novel prosthesis control strategies based on natural eye-hand and arm coordination, this dataset will also be useful to researchers interested in core sensorimotor control, humanoid robotics, human-robot interactions, as well as for the development and testing of associated solutions in gaze-guided computer vision.

Modeling passenger comfort in turboprop aircraft using objective measures.

A quantitative comfort model will aid in evaluating comfort levels of various target groups before the actual flight of an airplane. However, constructing the model is always a challenge due to the complexity of the phenomenon. In this paper, we present quantitative comfort models to predict the (dis)comfort of passengers flying with turboprops based on objective measures. Ninety-seven participants took part in two experiments conducted during real flights, during which forty of them had environmental and personal factors recorded using (self-developed) measurement tools. The collected data were analyzed to model the relations between objective measures and subjective feelings. Two preliminary models based on gradient boosting regression were developed. The models were able to predict the changes in comfort and discomfort of individual passengers with an accuracy of 0.12±0.01 and 0.21±0.01 regarding normalized comfort and discomfort scores, respectively. Additionally, contributions of different factors were highlighted. The outcomes of the models show that we took a step forward in modeling the human comfort experience using objective measurements. Anthropometry (including age), seat positions, time duration, and row (noise) emerged as leading factors influencing the feeling of (dis)comfort in turboprop planes.

A hybrid simulation approach to predicting noise in restaurants

High levels of noise are a well-known source of occupant discomfort in dining environments, and noise ranks highly among the most common customer complaints in restaurant reviews. Prior work has focused on measuring existing restaurant soundscapes and attempting to predict acoustic performance; however, current techniques are still limited in accuracy for restaurants with time-varying occupancy and complex layouts. This presentation demonstrates a novel approach to predicting ambient noise in restaurants via a hybrid simulation framework. Acoustical computations for a given restaurant space are performed in a room acoustics model, while a discrete event simulation (DES) model is used to simulate the arrival patterns of patrons and their conversational behaviors. Predictions from the room acoustics model inform the DES model, allowing for noise level predictions at each seat position. Results from the prediction model are validated against measurements in a case study restaurant. Further development of this framework may support the practical assessment of design interventions in any restaurant while also accounting for time-varying patterns of occupancy.

Ergonomic Design of Noseless Bicycle Saddle using UPVC/Silica-Aerogel

Introduction: During cycling most of the people suffer from perineal pain due to the pressure acting on the perineal area by the nose of the seat. Also Unsupported sitting on the saddle in a forward bending posture for longer time induce low back pain (LBP) among cyclists. So this paper presents the design of noseless bicycle seat with backrest using UPVC/Silica-Aerogel. Methods: This seat is designed as per the anthropometric dimensions of human body. Various parameters such as Lumbar position, seat tilt angle, seat position, backrest angle, seat height, backrest height, seat and backrest width are considered and the optimal value is determined while designing. The material chosen for the base of seat is UPVC/Silica- Aerogel composite and the cushioning material is chosen as polyurethene foam. The design is executed in 3D modelling software and validated using FEA package. Results: The maximum stresses induced in the newly proposed material UPVC/Silica-Aerogel (4.41MPa) is lesser than its yield strength (59 MPa). The maximum anterior stress of noseless seat is found out to be 24.5 kPa which is lower than that of the saddle with nose (41 kPa). Conclusion: As the anterior stress of noseless seat is lesser, the perineal pressure of cyclists is greatly reduced and this decreases the health problems associated with the perineal pressure. Also the backrest of the seatpan enhances the supporting of back muscles and reduces LBP among cyclists.

In silico analysis of the patient-specific acetabular cup anteversion safe zone

IntroductionVarious computer-assisted surgical systems claim to improve the accuracy of cup placement in total hip arthroplasties after assessing spinopelvic mobility to prevent prosthetic impingement. However, no study has yet analyzed the extent of the patient-specific cup anteversion safe zones. HypothesisWe hypothesized that most patients have a safe zone >10 °, except those with abnormal spinopelvic mobility, who have a much narrower safe zone. Materials and methodsWe simulated the risks of prosthetic impingement using the planned cup anteversion. The consecutive cohort included 341 patients who underwent total hip arthroplasty. Our primary endpoint was the patient-specific impingement-free zone for cup anteversion, which was then divided into four subgroups: 0 °, 1 ° to 5 °, 6 ° to 10 °, and >10 °. This data was then secondarily analyzed for abnormal spinopelvic mobility (the difference in the spinopelvic tilt [ΔSPT] from a standing to a flexed seated position >20 °). ResultsThe mean anteversion safe zone was 22.8 ° with 82.4% (281/341) of patients with a zone strictly >10 °. The mean safe zone was 8.9 ° (+/− 9 °) in patients with an ΔSPT ≥20 ° (18.2%), with 37.1% of these patients having a zone of 0 °, 16.13% a zone between 1 ° and 5 °, 8.06% a zone between 6 ° and 10 ° and 38.71% a zone >10 °. The mean safe zone was 25.9 ° (+/− 9 °) in patients with an ΔSPT <20 ° (81.8%), and the proportion of cases in each zone was 2.51%, 1.08%, 4.3%, and 92.11%, respectively (p < 0.001). ConclusionThe safe zone for anteversion appears to be fairly wide in most patients. However, identifying patients at risk of abnormal spinopelvic mobility seems necessary to identify the two-thirds of patients with a narrow safe zone. Level of evidenceIV; retrospective study

Classroom Management Problems Faced by English Education Students at Faculty of Teacher Training and Education University of Mataram Undertaking the Campus Teaching Program

This study addresses the challenges English Education students face in developing relationships, motivation, and engaging instruction in English classes. The research design is descriptive qualitative research, and the data collection methods include observation sheets, interviews, and document analysis. The study participants are five students who participated in the Kampus Mengajar or Campus Teaching (KM) program at University of Mataram and seek to identify the problems they encounter in classroom management, how they solve them, and how well they manage their classrooms. The result of both observation and interview founded that there are included six problems faced by KM-5 students during teaching practice i.e., (1) Naughty students, (2) Underestimate the teacher, (3) Hyper active students, (4) Passive students in learning activities, (5) Crowded classes and (6) Bored students. The efforts given by the KM students in dealing with the problems are building good teacher-student relationships, making the lesson more attractive, giving a small gift to catch students' attention, giving word motivation, changing students' seat positions, and making some games related to the topic discussion. The results highlight the need for further support and development opportunities for student teachers to enhance their classroom management skills and teaching practice.

MỐI LIÊN HỆ GIỮA VỊ TRÍ CHỖ NGỒI TRONG LỚP HỌC VỚI KẾT QUẢ HỌC TẬP MÔN HỌC “MẠNG MÁY TÍNH”

The paper investigates the correlation between seating positions in the classroom and academic performance in the subject of Computer Networks, specifically focusing on students from the Faculty of Information Technology at Thai Nguyen University of Information and Communication Technology. The research methodology employed scenarios, situations, interview questions, and real experimental cases involving 500 students. These students were assigned different seating arrangements in classrooms throughout the course, from the beginning to the end. Through specific input data, the study quantitatively assessed the relatively accurate research outcomes, based on the final exam results. The research results, comparisons, and practical evaluations indicate that seating positions are related to students' academic performance. Specifically, students achieving grades of C or higher are predominantly found in the front and middle rows, while those with grades below C are in the remaining rows

Vehicle Seat Adjustment System based on Body Image Recognition

A vehicle seat adjustment system based on body image recognition is designed. The system uses body image recognition algorithms to calculate the physique parameters of passengers, and automatically adjusts the vehicle seat position. Through on-site testing, the matching rate between the automatically adjusted vehicle seat position and passenger body shape reaches 98.1%, which can effectively improve the convenience and comfort of the vehicle.

The rise of multi-stakeholderism, the power of ultra-processed food corporations, and the implications for global food governance: a network analysis

AbstractThe rise of multi-stakeholder institutions (MIs) involving the ultra-processed food (UPF) industry has raised concerns among food and public health scholars, especially with regards to enhancing the legitimacy and influence of transnational food corporations in global food governance (GFG) spaces. However, few studies have investigated the governance composition and characteristics of MIs involving the UPF industry, nor considered the implications for organizing global responses to UPFs and other major food systems challenges. We address this gap by conducting a network analysis to map global MIs involving the UPF industry, drawing data from web sources, company reports, business and market research databases, and academic and grey literature. We identified 45 such global food system MIs. Of these, executives from the UPF industry or affiliated interest groups held almost half (n = 263, or 43.8%) of the total 601 board seat positions. Executives from a small number of corporations, especially Unilever (n = 20), Nestlé (n = 17), PepsiCo Inc (n = 14), and The Coca-Cola Company (n = 13) held the most board seat positions, indicating centrality to the network. Board seats of these MIs are dominated by executives from transnational corporations (n = 431, or 71.7%), high-income countries (n = 495, or 82.4%), and four countries (United States, Switzerland, United Kingdom, and the Netherlands) (n = 350, or 58.2%) in particular. This study shows that MIs involving the UPF industry privilege the interests of corporations located near exclusively in the Global North, draw legitimacy through affiliations with multi-lateral agencies, civil society groups and research institutions, and represent diverse corporate interests involved in UPF supply chains. Corporate-anchored multi-stakeholderism, as a form of GFG governance, raises challenges for achieving food systems transformation, including the control and reduction of UPFs in human diets.

The Correlation Between Classroom Seating Position and Speaking Ability of a 9th Grader

The Correlation Between Classroom Seating Position and Speaking Ability of a 9th Grader

Design and Testing of 3D Textile Materials with Vibro-Insulating Properties, Applicable in the Construction of Vibroisolating Seats for Machine and Device Operators

Abstract In this article, the author describes the problem with low frequency vibrations in the range of 0–100 Hz and how exposure to these vibrations could affect human health when working in dangerous environments. For this research, vibrations in the range of 0–30 Hz were studied as this frequency range has the largest impact on human health and such vibrations usually occur when operating excavators, forklifts or Melex vehicles. Workers who are exposed to these vibrations usually work in a seated position for many hours. Over time, exposure to dangerous vibrations in the working environment will cause damage to the human spine, resulting in a great deal of discomfort for the worker. In order to alleviate the pain, the worker will tend to shift their seating position away from the correct position, which further compounds the issue. The author proposes the use of a 3D knitted seat mat in order to reduce the amplitude of any harmful vibrations. This will provide better ergonomic conditions for the user and will reduce the effects of low frequency vibrations.

Nasal Patency Across Seated, Supine, and Recumbent Postures in Individuals With and Without Allergic Rhinitis.

Objectives: This study aimed to investigate the effects of seated, supine, and recumbent postures on nasal resistance in individuals with allergic rhinitis (AR) and healthy controls, which has not been investigated in the past. Methods: A visual analog scale (VAS) assessed subjective nasal obstruction, while acoustic rhinometry and video endoscopy provided objective measures. Sixty participants, comprising 30 AR patients and 30 healthy controls, were evaluated across 4 postures without decongestion: seated, supine, left recumbent, and right recumbent. Results: In patients with AR, we noted no significant changes in subjective nasal blockage under various postures (all P > .18). However, significant reductions of minimal cross-sectional area (mCSA) were found (seated vs supine, P = .014; seated vs left recumbent, P = .001; seated vs right recumbent, P < .001) and significant increases in the inferior turbinate hypertrophy were observed on the dependent side of the nose when in recumbent posture (right nose: seated vs right recumbent, P = .013; left nose: seated vs left recumbent, P = .003). On the contrary, healthy controls experienced increased subjective nasal obstruction (VAS scores: seated vs supine, P < .001; seated vs left recumbent, P = .003; seated vs right recumbent, P < .001), reductions in mCSA (seated vs supine, P = .002; seated vs right or left recumbent, both P = .001), and increased inferior turbinate hypertrophy on the dependent side of the nose (right nose: seated vs right recumbent, P = .003; left nose: seated vs left recumbent, P = .006). Conclusions: Healthy controls reported better nasal patency when shifting from supine or recumbent to more upright or less gravity-dependent seated postures, which was further supported by objective examinations. On the contrary, despite patients with AR not subjectively perceiving increased nasal patency while adopting more upright postures, objective evaluations demonstrated an improvement in their nasal airflow in these less gravity-dependent postures.Level of Evidence: 4.

Quantifying rider posture variability in powered two- and three-wheelers for safety assessment

Objective Injury outcomes for powered two- and three-wheeler (PTW) riders are influenced by the rider posture. To enable analysis of PTW rider accidents and development of protection systems, detailed whole-body posture data is needed. Therefore, the aim of this study is to fill this gap by providing collections of average male whole-body postures, including subpopulation variability, for different PTW types. This will enable future studies to explore the influence of PTW rider posture variation and to support safety system development. Methods 3D photometric measurements of 51 anatomical landmarks were recorded on 20 (50th percentile male) volunteers in their preferred riding postures across three PTW types (naked, scooter, and touring). Following an outlier removal process, a principal component analysis (PCA) was performed to calculate average postures and principal components (PCs), to describe the observed posture variation, for each PTW. The visualization of the PCs was facilitated through kinematic linkage representations, connecting anatomical landmarks and estimated joint centers to form segments and characteristic joint angles. Results The first seven PCs explained 80% of the variance in posture for each of the three PTWs. Across PTWs, these PCs frequently described combinations of postural features including variation in fore-aft seat positions, pelvic tilt, spinal curvature, head position, and extremity flexion-extension. Analysis revealed distinct differences in average postures across the three PTWs, on average, 10 ± 9° for the characteristic joint angles within a min-to-max range between the three PTWs. However, for all three PTWs, the variability between volunteers in characteristic joint angles on the same PTW were on average more than twice as large within a ± 2 SD range (26 ± 11°). Conclusions The results suggest that PTW rider posture variation must be addressed by involving simultaneous adjustments of multiple body parts, as described by each of the first seven PCs, as a direct consequence of the human body interconnectedness. Furthermore, the study’s findings challenge conventional assumptions that the relative distance between PTWs’ handlebar, seat, and foot support predominantly influences rider postures. Instead, the research demonstrates that individual variability has a substantial influence on rider posture and should be considered in PTW safety development.

Validation of intraocular pressure measurement using tonometer AVIA across different postures: A Bland Altman analysis.

Tonometry is a fundamental procedure in the diagnosis and management of glaucoma. Different tonometers have been proposed but none are as accurate as the Goldman applanation tonometry (GAT). Nonetheless, due to the limitations of GAT, mobile tonometry methods became prevalent. This study aims to examine the reliability of the Tono-Pen AVIA® (TPA) in measuring intraocular pressure (IOP) across different postures. A total of 196 eyes were prospectively examined for IOP changes using GAT and TPA. IOP measurements were taken across different postures using the TPA. Reliability of measurements was compared using interclass correlation coefficients (ICC), while agreement was represented using Bland-Altman analysis. Pearson r coefficient was used to measure correlations. When compared to GAT (14.5 ± 4.4 mmHg), IOP readings were significantly higher for TPA at both seated (16.5 ± 4.5 mmHg; p < 0.001) and supine (16.9 ± 5.7; p < 0.001) positions. The ICC values for GAT and TPA among seated and supine patients were 0.79 (0.54-0.90) and 0.76 (0.48-0.87) indicating good reliability between the readings. There were significantly positive correlations between GAT and TPA at both seated (r = 0.626, p < 0.001) and supine (r = 0.727, p < 0.001) positions. Per Bland-Altman analysis, limits of agreement were -8.57 to 4.37 for GAT and seated TPA and -10.34 and 5.34 for GAT and supine TPA. Good reliability exists between IOP measurements using GAT and TPA. However, the devices are not interchangeable and therefore cannot be used reciprocally in the same patient.