Seat Control Research Articles

Ultrasonographic Evaluation of the Effect of Osteopathic Manipulative Treatment on Sacral Base Asymmetry.

Patients with low back pain (LBP) may receive osteopathic manipulative treatment (OMT) to resolve or manage their pain. The indication for OMT for patients with LBP is the presence of somatic dysfunction, diagnosed using palpatory examination. Because palpatory findings commonly have poor interexaminer reliability, the current study used ultrasonography (US) to establish pre-OMT and post-OMT musculoskeletal measurements of relative asymmetry between pelvic and sacral bony landmarks. To document objective musculoskeletal changes that occur in response to OMT using US and to compare palpatory assessment of landmark asymmetry with US assessment. Sixty men and women aged 20 to 55 years with at least 1 episode of LBP in the past 2 weeks were assigned to a seated control, walking control, or OMT group (20 participants per group). Participants received an initial, bilateral US measurement of the skin to posterior superior iliac spine (SPSIS), skin to sacral base position (SBP), and sacral sulcus depth (SSD). Participants in seated control and OMT groups received a palpatory assessment of SBP and SSD prior to initial US assessment. After assessment, the seated control group sat in a waiting room for 30 minutes, the walking control group walked for 5 minutes, and the OMT group received OMT to address sacral base asymmetry using predominantly direct techniques for a maximum of 20 minutes. Participants then received a second US assessment of the same structures. Body mass index (BMI) was correlated with SPSIS (r=0.5, P=.001) and SBP (r=0.6, P<.001). More participants in seated control (75%) and OMT (65%) groups had an increase in asymmetry from first to second US assessment for SPSIS compared with participants in the walking control group (35%, P=.05). No significant differences were found between groups for absolute asymmetry or total change in asymmetry (all P>.10). The κ was -0.1 (95% CI, -0.2 to 0.03) for SBP and -0.01 (95% CI, -0.1 to 0.1) for SSD. Musculoskeletal changes in SPSIS and SBP measurements related to OMT could not be readily identified using US. The SPSIS and SBP measurements were dependent on BMI, which may have affected the accuracy of US to detect small changes in asymmetry. Qualitative palpatory assessments did not correlate with US measurements. Further study is needed to identify US measurements that demonstrate change with OMT. (ClinicalTrials.gov number NCT02820701).

Development of a hardware-in-the-loop simulation system for power seat and power trunk electronic control unit validation

This paper describes a hardware-in-the-loop simulation system for the validation of a vehicle body electronic control unit. The hardware-in-the-loop simulation system consists of three parts: a real-time target machine, an electronic control unit, and a signal conditioning unit, which regulates the voltage levels between the real-time target and the electronic control unit. The real-time target machine generates switch and feedback signals to the electronic control unit. The software model, representing body electronics hardware, such as a power seat and power trunk, runs inside a real-time target machine. The software model is composed of a mechanical part that represents the dynamic behaviors and an electronic part to calculate the motor speeds, current, and electronic loads under various conditions. The hardware-in-the-loop test was carried out for two different large passenger vehicle electronic control units, since the purpose of this research is to validate the various electronic control units by just simply modifying the corresponding vehicle model, the power seat, and the power trunk. Test results indicate that the developed software model can effectively replace the real hardware, and that this virtual model can be used to validate the signal logic between the electronic control unit and the model. In addition, the electrical robustness of the electronic control unit was validated by applying surge currents to the electronic control unit.

The Effects of Repeated, Consecutive High-Intensity Exercise on Cognitive Performance in Well-Trained Team Sports Players

Improvements in cognitive performance and mood are generally accepted following moderate intensity exercise; however, the impact of high-intensity exercise is less clear. Given that professional team sports are performed at high or maximal intensity, which can be further compounded during periods of intensified periods of competition, investigations into the effect of such exercise on cognition are needed. PURPOSE: To determine the effect of repeated high-intensity exercise on cognitive function, mood and perceptions of both physical and mental energy, and fatigue. METHODS: In a counterbalanced crossover design, twenty-four well-trained, sub-elite rugby players (mean ± SD age, height, mass were 20.7 ± 1.9 yrs, 181.7 ± 5.5 cm, 88.2 ± 9.0 kg, respectively) completed a series of repeated sprints (20 x 20 m, three times per day for two consecutive days) or a seated control. Prior to and following each set of sprints or equivalent control duration, a selection of cognitive tests including simple reaction time, four-choice reaction time (FCRT), Corsi blocks and Stroop task (ST) were completed in addition to visual analogue scales assessing mood, energy and fatigue. Repeated-measures ANOVAs were conducted with pairwise comparisons where necessary (α = 0.05). RESULTS: No changes were observed in any cognitive, mood, energy or fatigue measures after one single high-intensity session. However, compared to the control, ST accuracy was lower in the exercise condition (-0.6 %, P < 0.05) which was largely due to a sharp decline at bout 3 on day 1 that continued throughout day 2. Additionally, FCRT was slower on day 2 (+2.2 %) whilst feelings of alertness (-12 %), contentedness (-5 %), and physical (-22 %) and mental (-24 %) energy were reduced and ratings of physical (+22 %) and mental (+40 %) fatigue increased (all day 2 vs. day 1, P < 0.05). No changes were observed in the control condition. CONCLUSION: Intensified periods of exercise have detrimental effects on cognitive performance, mood and perceptions of physical and mental energy, and fatigue. The deleterious effects on these parameters could be contributing to increased injury rates during fixture congestion alongside decrements in performance. Player rotation may help alleviate these effects whilst also prompting further research into cognitive recovery strategies.

Dose-Response of Light Intensity Physical Activity and Glucose Dynamics in Older Adults

National data reports older adults spend about 30% of their day in light intensity physical activity (LPA). This study was designed to examine how increasing the proportion of the day spent in LPA would affect glucose control. PURPOSE: To determine the duration-response of proportion of time spent in LPA on post-prandial glucose response in older adults in a controlled environment. METHODS: Older adults (N=9), 60 y and older, completed four, three-hour treatment conditions, a seated control condition, and three subsequent randomized conditions 1) 20% (36 min) of the condition spent in continuous LPA, the remaining time seated, 2) 40% (72 min) of the condition spent in continuous LPA, the remaining time seated, and 3) 60% (108 min) of the condition spent in continuous LPA, the remaining time seated. Energy expenditure was measured continuously and glucose was measured at baseline following mixed meal ingestion and each hour thereafter. Glucose AUC was calculated and compared between conditions using RMANOVA. RESULTS: A significantly greater amount of energy was expended during all activity conditions when compared to the seated condition (p<0.05). There was a significant difference between proportion of time spent in LPA and glucose AUC (F=11.601, p<0.001). Post-hoc analysis showed a significant difference between the seated condition and 60% LPA condition (AUC mean difference (Seated-60%): 35.0 mg/dL, p=0.016), 20% LPA condition and 60% LPA condition (AUC mean difference (20%-60%): 17.3 mg/dL, p=0.010), and 40% LPA condition and 60% LPA condition (AUC mean difference (40%-60%): 9.8 mg/dL, p=0.023) CONCLUSION: These results provide experimental evidence to the importance LPA may play in the overall metabolic health of an older adult population. According to national data, LPA constitutes about 30% of the active day in older adults. Therefore, the translation of the current results suggest that if older adults, who spend on average about three hours per day in LPA, increase LPA by 36 min/d they could significantly benefit glucose control.

Variation of plate fixation for mandibular advancement with intraoral vertical ramus osteotomy using endoscopically-assisted intraoral rigid or semi-rigid internal fixation: postoperative condylar seating control for mandibular advancement

Variation of plate fixation for mandibular advancement with intraoral vertical ramus osteotomy using endoscopically-assisted intraoral rigid or semi-rigid internal fixation: postoperative condylar seating control for mandibular advancement

Dynamic pricing &amp; capacity assignment problem with cancellation and mark-up policies in airlines

Abstract Revenue management has started on the capacity control by booking classes for available seats, and has been recognized as a powerful tool to maximize the total revenue. Among various RM techniques, pricing and seat controls have played key roles in airlines. Since pricing and seat control problems are highly correlated in RM problem. These two decision problems need to be considered jointly. However, due to the complex interaction between them, a few researches focus on the joint pricing and seat control problem. In this paper we consider a comprehensive problem including a cancellation in booking processes and a mark-up policy in pricing strategy under uncertain demands. To manage the demand uncertainty efficiently, we applied a linear approximation technique and proposed a new approximation model, a simple mixed Integer Programming model. From the computational experiments with randomly generated data, we can find our model makes good performance for deciding pricing and seat controls simultaneously.

Numerical analysis using state space method for vibration control of car seat by employing passive and semi active dampers

In passenger cars the vibrations developed at the ground are transmitted to the passengers through seats. Due to vibrations discomfort is experienced by the passengers. Dampers are being successfully utilized to reduce the vibrations in civil engineering structures. Few dampers are used in passenger cars as well. In the present study viscous dampers and semi-active variable friction dampers are used in passenger cars. The car and car seat are modeled together as two degrees of freedom system. The study is carried out for two cases namely car moving on sagged bridges and car moving on road humps. The paper also presents the comparison of performance of both the dampers for the two cases. State space method has been employed for the numerical analysis of the study. It is found that the amplitude of displacements is reduced considerably by the employment of dampers and resonance is avoided. Performance wise viscous damper is found to be slightly better than semi-active variable friction damper.Keywords: Car seat, viscous damper, semi-active variable friction damper, two degrees of freedom, state space method

Call Center Productivity Over 6 Months Following a Standing Desk Intervention

OCCUPATIONAL ABSTRACTStand-capable desks have been shown to successfully reduce sedentary behavior in the modern office, but whether their utilization improves cognitive productivity is not known. We compared productivity between stand-capable desk users and traditional seated desk users in a call center environment. Data were collected daily over a continuous 6-month period. We found that increased stand-capable desk use is a likely contributor to increased productivity over traditional seated desk use. These findings indicate that use of stand-capable desks as ergonomic interventions to improve physical health among employees may also positively impact their work productivity.TECHNICAL ABSTRACT Background: Many office employees are spending up to 90% of their workday seated, and employers are considering stand-capable desks as a way to increase physical activity throughout the day. When deciding on adoption of stand-capable workstations, a major concern for employers is that the benefits, over time, may not offset the initial cost of implementation. Methods: This study compared objective measures of productivity over time between a group of stand-capable desk users and a seated control group in a call center. Comparison analysis was completed for continuous 6-month secondary data for 167 employees, across two job categories. Results: Users of stand-capable desks were ∼45% more productive on a daily basis compared to their seated counterparts. Further, productivity of the stand-capable desk users significantly increased over time, from ∼23% in the 1st month to ∼53% over the next 6 months. Finally, this productivity increase was similar for employees across both job categories. Conclusions: These findings suggest important benefits of employing stand-capable desks in the work force to increase productivity. Prospective studies that include employee health status, perceptions of (dis)comfort and preference over time, along with productivity metrics, are needed to test the effectiveness of stand-capable desks on employee health and performance.

Active Vibration Control of Passenger Seat with HFPIDCR Controlled Suspension Alternatives

Active Vibration Control of Passenger Seat with HFPIDCR Controlled Suspension Alternatives

Effects of a High-Intensity Functional Exercise Program on Dependence in Activities of Daily Living and Balance in Older Adults with Dementia.

ObjectivesTo investigate the effects of a high-intensity functional exercise program on independence in activities of daily living (ADLs) and balance in older people with dementia and whether exercise effects differed between dementia types.DesignCluster-randomized controlled trial: Umeå Dementia and Exercise (UMDEX) study.SettingResidential care facilities, Umeå, Sweden.ParticipantsIndividuals aged 65 and older with a dementia diagnosis, a Mini-Mental State Examination score of 10 or greater, and dependence in ADLs (N = 186).InterventionNinety-three participants each were allocated to the high-intensity functional exercise program, comprising lower limb strength and balance exercises, and 93 to a seated control activity.MeasurementsBlinded assessors measured ADL independence using the Functional Independence Measure (FIM) and Barthel Index (BI) and balance using the Berg Balance Scale (BBS) at baseline and 4 (directly after intervention completion) and 7 months.ResultsLinear mixed models showed no between-group effect on ADL independence at 4 (FIM=1.3, 95% confidence interval (CI)=−1.6–4.3; BI=0.6, 95% CI=−0.2–1.4) or 7 (FIM=0.8, 95% CI=−2.2–3.8; BI=0.6, 95% CI=−0.3–1.4) months. A significant between-group effect on balance favoring exercise was observed at 4 months (BBS=4.2, 95% CI=1.8–6.6). In interaction analyses, exercise effects differed significantly between dementia types. Positive between-group exercise effects were found in participants with non-Alzheimer's dementia according to the FIM at 7 months and BI and BBS at 4 and 7 months.ConclusionIn older people with mild to moderate dementia living in residential care facilities, a 4-month high-intensity functional exercise program appears to slow decline in ADL independence and improve balance, albeit only in participants with non-Alzheimer's dementia.

Variation of plate fixation for mandibular advancement with intraoral vertical ramus osteotomy using endoscopically assisted intraoral rigid or semi-rigid internal fixation: Case series study: Postoperative condylar seating control for mandibular advancement.

The purpose of the present study was to evaluate the safety and efficacy associated with mandibular advancement by intraoral vertical ramus osteotomy (IVRO) with endoscopically assisted intraoral rigid or semi-rigid internal fixation. The study sample included all patients who had undergone an mandibular advancement by IVRO procedure with endoscopically assisted intraoral plate fixation from September 2008 to May 2012. An mandibular advancement by IVRO with endoscopically assisted intraoral rigid or semi-rigid internal fixation was used for mandibular advancement. The patients were analyzed prospectively, with more than 2 years of follow-up, and were evaluated in terms of functional results, postoperative complications, and skeletal stability. A total of 14 patients (bilateral, 7 patients with class II; unilateral, 7 patients with asymmetry) were included in the present study. The average degree of mandibular advancement was 5.5±1.9mm (range, 3-9mm). Both the occlusal relationship and facial appearance in all patients were significantly improved by the surgical-orthodontic treatment, with no major harmful clinical symptoms. In addition, one-screw semi-rigid fixation could control postoperative passive condylar seating. This study showed that mandibular advancement by IVRO with endoscopically assisted, intraoral semi-rigid internal fixation offers a promising treatment alternative for patients with skeletal class II malocclusion or facial asymmetry.

Neurophysiological and behavioral correlates of cognitive control during low and moderate intensity exercise

The aim of this study was to examine neurophysiological and behavioral correlates of cognitive control elicited by a modified flanker task while exercising at low and moderate intensities. A secondary aim was to examine cognitive control processes at several time points during an acute bout of exercise to determine whether cognition is selectively influenced by the duration of exercise. Twenty-seven healthy participants completed a modified version of the Eriksen flanker task while exercising on a cycle ergometer at 40% and 60% VO2 peak and during a no-exercise seated control across three separate days. During task performance, continuous EEG was collected to assess neurocognitive function using the N2 and P3 event-related brain potentials (ERPs). Neurocognitive performance was assessed at 5, 15, and 25min time points during steady-state exercise. Regardless of intensity, behavioral findings revealed impaired accuracy during both exercise conditions for the flanker task trials that require greater cognitive control. However, faster reaction times were found during moderate-intensity exercise. Neuroelectric measures revealed increased N2 and P3 amplitudes during both exercise conditions relative to rest. Together, these findings suggest divergent effects of exercise on behavioral performance measures accompanied by an upregulation of cognitive control during aerobic exercise. These impairments are discussed in terms of dual-task paradigms and the transient hypofrontality theory.

Design of a new adaptive fuzzy controller and its application to vibration control of a vehicle seat installed with an MR damper

This paper presents a new adaptive fuzzy controller featuring a combination of two different control methodologies: H infinity control technique and sliding mode control. It is known that both controllers are powerful in terms of high performance and robust stability. However, both control methods require an accurate dynamic model to design a state variable based controller in order to maintain their advantages. Thus, in this work a fuzzy control method which does not require an accurate dynamic model is adopted and two control methodologies are integrated to maintain the advantages even in an uncertain environment of the dynamic system. After a brief explanation of the interval type 2 fuzzy logic, a new adaptive fuzzy controller associated with the H infinity control and sliding mode control is formulated on the basis of Lyapunov stability theory. Subsequently, the formulated controller is applied to vibration control of a vehicle seat equipped with magnetorheological fluid damper (MR damper in short). An experimental setup for realization of the proposed controller is established and vibration control performances such as acceleration at the driver’s seat are evaluated. In addition, in order to demonstrate the effectiveness of the proposed controller, a comparative work with two existing controllers is undertaken. It is shown through simulation and experiment that the proposed controller can provide much better vibration control performance than the two existing controllers.

The relationship between self-reported and physical function in individuals with hip osteoarthritis

Additional analysis of the between group effect among men showed a mean difference from baseline to 7 months of 0.58 points amongmen in exercise group and−1.43 points among men in the control group (p= 0.003). Conclusion(s): A high-intensity exercise program generally seems to have no superior effect on well-being compared to a seated control activity amongpeoplewith dementia living in care facilities. However among men, the exercise program may be beneficial with respect to well-being, compared to the control activity. Implications: Exercise as a single intervention may not influence well-being among older people with dementia, and an individualized and multifactorial intervention may be needed. In addition, there may be gender differences in the effects of exercise that are important to investigate in future research.

Adaptive control of an active seat for occupant vibration reduction

The harmful effects on human performance and health caused by unwanted vibration from vehicle seats are of increasing concern. This paper presents an active seat system to reduce the vibration level transmitted to the seat pan and the occupants’ body under low frequency periodic excitation. Firstly, the detail of the mechanical structure is given and the active seat dynamics without external load are characterized by vibration transmissibility and frequency responses under different excitation forces. Owing the nonlinear and time-varying behaviour of the proposed system, a Filtered-x least-mean-square (FXLMS) adaptive control algorithm with on-line Fast-block LMS (FBLMS) identification process is employed to manage the system operation for high vibration cancellation performance. The effectiveness of the active seat system is assessed through real-time experimental tests using different excitation profiles. The system identification results show that an accurate estimation of the secondary path is achieved by using the FBLMS on-line technique. Substantial reduction is found for cancelling periodic vibration containing single and multiple frequencies. Additionally, the robustness and stability of the control system are validated through transient switching frequency tests.

Ride Comfort Performance of Active Vehicle Suspension with Seat Actuator Based on Non-Fragile H∞ Controller

The purpose of this paper is to investigate an active seat suspension system with two active actuators using a non-fragile robust control strategy. A simple deterministic vibration model of human body is added to the seat suspension dynamical model in order to make the modeling more accurate. Desired controller is obtained by solving a linear matrix inequality formulation by considering the vertical body acceleration as measurement signal. Finally, the effect of the seat actuator and controller gain variations on the closed-loop system performance is investigated numerically for two deterministic external excitations: bump and a realization of Gaussian white noise. Simulations show that the seat actuator has a noticeable effect on the seat suspension performance especially under random disturbances.

Development and verification of a multi-body dynamic model for seat-occupant system of manned spacecraft

The main goal of this study is to develop a novel multi-body dynamic model for seat-occupant system of a manned spacecraft. The seat of a spacecraft and its components has significant effects on an astronaut’s body during flight mission, where sustained accelerations and impact loads are inevitable. Besides, conducting sustained acceleration and shock loads on the body of astronauts during flight missions is the key factor for health conservation. This study develops a new multi-body dynamic model for seat-occupant system of manned spacecraft to investigate the effects of spacecraft seat design. The astronaut is modelled as a four-jointed rigid link placed on a viscoelastic cushion. The cushion is modelled to present polyurethane foam, which is using in almost all automotive and aerospace applications. The equations of motion are derived and the effects of different parameters are investigated. To verify the developed model, a finite element model is presented to implement the same exact multi-body model. The results show that the presented analytical multi-body model is in good accordance with the finite element model. The effects of different parameters such as foam discretisation, foam thickness and geometry of seat frame on the motion of the system are illustrated. This novel model can be used in designing spacecraft seat to preserve an astronaut’s health. It also can be used in seat control applications and where computational efficiency is necessary.

Cognitive function during low-intensity walking: a test of the treadmill workstation.

The purpose of this study was to examine the effects of walking at self-selected speed on an active workstation on cognitive performance. Sixty-six participants (n = 27 males, 39 females; mean age = 21.06 ± 1.6 years) completed a treadmill-desk walking and a seated control condition, separated by 48 hours. During each condition, participants completed computerized versions of the Stroop test, a modified flanker task, and a test of reading comprehension. No significant differences in response speed or accuracy were found between walking and sitting conditions for any the cognitive tests. These findings reveal that performance on cognitive tasks, including executive control processes, are not impaired by walking on an active workstation. Implementing active workstations into offices and classrooms may help to decrease sedentariness without impairing task performance.

Multi-Leg Seat Inventory Control Based on EMSU and Virtual Bucket

Expected marginal seat revenue (EMSR) is a well-known method for airline seat inventory control airlines. However, this method employs a static model to study the dynamic reservation process, and does not take into account the risk tolerance of policy makers. Expected marginal seat utility (EMSU) replaces revenue by utility, which addresses the real situation of seat inventory control. However, there is still a lack of multi-leg seat control algorithms based on EMSU. Therefore, using EMSU and bucket algorithms, this paper applies the Markov decision-making process to simulate the flight reservation process and builds a dynamic multi-leg seat inventory control model. Experimental results validate the effectiveness of the proposed method.

Development of a New Type 4D Dynamic Seat Platform Control System Based on PLC

This article has introduced the development method of a kind of 4d cinema dynamic seat control system based on PLC, expounds the system's hardware structure , working principle, function characteristics, etc. The system's power is provided by hydraulic pump, hardware adopts closed loop feedback control system constituted by omron PLC, A/D module, D/A module, linear displacement sensor and electromagnetic proportional directional valve. The system has good stability, high cost performance, miniaturization, intelligent, etc.