Lifting Technique Research Articles

Nested vehicle routing problem: Optimizing drone-truck surveillance operations

Unmanned aerial vehicles or drones are becoming increasingly popular due to their low cost and high mobility. In this paper we address the routing and coordination of a drone-truck pairing where the drone travels to multiple locations to perform specified observation tasks and rendezvous periodically with the truck to swap its batteries. We refer to this as the Nested-Vehicle Routing Problem (Nested-VRP) and develop a Mixed Integer Quadratically Constrained Programming (MIQCP) formulation with critical operational constraints, including drone battery capacity and synchronization of both vehicles during scheduled rendezvous. An enhancement of the MIQCP model for the Nested-VRP is achieved by deriving the equivalent Mixed Integer Linear Programming (MILP) formulation as well as leveraging lifting and Reformulation-Linearization techniques to strengthen the subtour elimination constraints of the drone. Given the NP-hard nature of the Nested-VRP, we further propose an efficient neighborhood search (NS) heuristic where we generate and improve on a good initial solution by iteratively solving the Nested-VRP on a local scale. We provide comparisons of both the exact approaches based on MIQCP or its enhanced formulations and NS heuristic methods with a relaxation lower bound in the cases of small and large problem sizes, and present the results of a computational study to show the effectiveness of the MIQCP model and its variants as well as the efficiency of the NS heuristic, including for a real-life instance with 631 locations. We envision that this framework will facilitate the planning and operations of combined drone-truck missions.

A unified framework of convex stability conditions for 2-D switched systems with stable or unstable modes

The discrete-time two-dimensional (2-D) switched system is a powerful tool to model many practical physical processes with abrupt changes. However, the stability analysis problem for 2-D switched systems struggles to provide a unified framework for stable or unstable modes. Users have to delicately tune lots of parameters to shape the Lyapunov function for each mode. Besides, the resulting stability conditions are non-convex and thus the feasibility highly depends on the tuning parameters. In this paper, we propose a unified stability framework for 2-D switched systems, formulated by the well-known Fornasini–Marchesini local state-space model and the Roesser model. The concepts called unit switching sequence (USS) and sequence generator are presented. A novel Lyapunov function is also accordingly established which views the switching sequence as a concatenation of USSs, different from the perspective that regards the switching sequence as a combination of subsystems in previous literatures. Upon this framework, a convex stability criterion is developed, and the conservativeness can be lowered by a lifting technique at the expense of a higher off-line computational complexity. The derived theories are further extended for a standard l2-gain which is achieved under restricted switching signals for the first time. Numerical examples are provided for validity verification, conservativeness comparison, and l2-gain computation.

Lifting the Mouth Corner: A Systematic Review of Techniques, Clinical Outcomes, and Patient Satisfaction.

BackgroundMouth corners are an essential part of the centrofacial area for perception of attractiveness and emotions. Downturned mouth corners are a result of aging or have a congenital origin. Different mouth corner lifting techniques are described in the literature.ObjectivesThis review was performed to systematically assess and compare invasive and noninvasive mouth corner lifting techniques and their effectiveness, patient satisfaction, and adverse effects.MethodsMEDLINE (via PubMed), EMBASE (OvidSP), and the Cochrane Central Register of controlled trials databases were searched for clinical and observational studies published in peer-reviewed academic journals with abstracts available (searched from May 18, 2019, to December 18, 2021). Outcomes of interest were aesthetic mouth corner lifting techniques, the degree of lift as well as the longevity of the lifting effect, patient satisfaction, and adverse effects. Techniques were subdivided in invasive techniques and noninvasive techniques.ResultsOut of 968 studies found from the search, 11 were included in the qualitative analysis. In general, surgical techniques seem to have a better mouth corner lifting effect than nonsurgical techniques; however, objective evidence is weak, and surgery inevitably results in a scar. Reported patient satisfaction was good for both surgical and nonsurgical techniques and no severe complications have been described.ConclusionsSurgical techniques seem to have a better lifting effect on mouth corners than nonsurgical techniques. Nevertheless, objective evidence is weak, and a scar is inevitable.Level of Evidence: 4

Minimum-Variance State and Fault Estimation for Multirate Systems With Dynamical Bias

This brief is concerned with the joint state and fault estimation problem for a class of multi-rate systems with dynamical bias. To reflect real practice, the multi-rate sampling is considered which allows the sensor sampling rate and the state update rate to be different. The sensor is subject to the sensor fault that changes according to a dynamic equation. Instead of applying the traditional lifting technique, we introduce a time-varying delay into the measurement equation so as to transform the multi-rate systems into single-rate ones. The aim of this brief is to develop a joint state and fault estimation algorithm with minimized estimation error covariance. The recursion of the estimation error covariance is first derived, and appropriate estimator gains are then characterized that minimizes the estimation error covariance. A simulation example on the DC servo system is given to confirm the usefulness of the developed recursive state and fault estimation algorithm.

Digital H∞ filter design for a low frequency multiple‐input multiple‐output system with multirate measurements

AbstractIn this article, a digital filter is designed for a low frequency multiple‐input multiple‐output (MIMO) system with multirate measurements from multiple samplers. A delay compensation is introduced to reduce estimation errors from the multiple samplers and a zero‐order holder. A single‐rate error system is obtained by converting the low frequency MIMO system using a discrete‐time lifting technique. A digital filter is proposed based on a delay‐partitioning method to guarantee asymptotic stability and performance for the single‐rate error system. A numerical example is provided to show effectiveness and superiority of the digital filter in low frequency domain.

Anti‐disturbance resilient tracking control for semi‐Markov jumping systems

AbstractThis article investigates the output tracking problem of semi‐Markov jump systems with exogenous disturbance and generally uncertain transition probability rates. In particular, the elements in the transition rates are allowed to be known, uncertain or completely unknown. In specific, a state‐space of the modified repetitive controller is considered for tracking the given reference signals. Then, a generalized extended state observer is constructed to estimate the external disturbances and these estimates are incorporated in the control law to reject the disturbances effectively. Moreover, additive gain fluctuations are considered in the control design to tolerate gain fluctuations. First, a continuous‐discrete two‐dimensional (2D) delayed system is developed based on the lifting technique to characterize the repetitive control system's control and learning behavior. Then a sufficient condition for the bounded stability of the 2D hybrid system is obtained by choosing a suitable Lyapunov–Krasovskii functional. In addition, the control and observer gains are evaluated by solving a set of linear matrix inequalities and using the pole placement technique. At last, a robot arm model is presented to show the applicability of the proposed control scheme and a comparison study is made over some existing literature.

Lifting Techniques: Why Are We Not Using Evidence To Optimize Movement?

Lifting something off the ground is an essential task and lifting is a documented risk factor for low back pain (LBP). The standard lifting techniques are stoop (lifting with your back), squat (lifting with your legs), and semi-squat (midway between stoop and squat). Most clinicians believe the squat technique is optimal; however, training on squat lifting does not prevent LBP and utilizing greater lumbar flexion (i.e. stoop) when lifting is not a risk factor for LBP. The disconnect between what occurs in clinical practice and what the evidence suggests has resulted in ongoing debate. Clinicians must ask the right questions in order to apply the evidence appropriately. A proposed clinical framework of calm tissue down, build tissue up, improve work capacity can be used to determine which lifting technique is optimal for a patient at any given time. When applying this clinical framework, clinicians should consider metabolic, biomechanical, physical stress tolerance, and pain factors in order to address the movement system. For example, stoop lifting is more metabolically efficient and less challenging to the cardiopulmonary system. There may be few biomechanical differences in spinal postures and gross loads on the lumbar spine between stoop, squat, and semi-squat lifting; however, each lift has distinct kinematic patterns that affects muscle activation patterns, and ultimately the movement system. Clinicians must find the optimal dosage of physical stress to address all aspects of the movement system to minimize the risk of injury. There is no universal consensus on the optimal lifting technique which will satisfy every situation; however, there may be a lifting technique that optimizes movement to achieve a specific outcome. The calm tissue down, build tissue up, improve work capacity framework offers an approach to determine the best lifting technique for an individual patient at any give time.Level of Evidence5

Prevalence and factors associated with low back pain among health care providers in public hospitals of Gamo zone, Southern Ethiopia.

Objectives:To assess prevalence and factors associated with low back pain among health care providers in public hospitals of Gamo zone, Southern Ethiopia, 2021.Methods:An institution-based cross-sectional study design was employed from August 1 to September 10, 2021. The total sample size was 470 and a multi-stage sampling technique was used. Data were collected through face-to-face interviews and taking Anthropometric measurements. Epi data version 3.1 for data entry and SPSS version 25 for analysis were used. The fitness of the model was checked using the Hosmer–Lemeshow goodness of fit test. A binary logistic regression analysis was done, and variables with a p-value of less than .025 in univariate analysis were taken to bivariate analysis. Statistically significant was declared at a p-value of less than .05 with an adjusted odds ratio and 95% confidence interval.Results:The 1-year prevalence of low back pain among health care providers was 44.2% (95% CI 39.5–48.3). Past medical history of systemic illness, most commonly adopted posture, a job never requiring repeating motions within 60 s difference, belief that working health profession activities at night aggravate low back pain, and job satisfaction were significantly associated with low back pain, believing that working at night aggravated low back pain, (often lift, push, pull carry or move) more than 10 kg alone, and job satisfaction were important risk factors for low back pain.Conclusion:About four in 10 health care providers in public hospitals in the Gamo zone were suffering from low back pain. Therefore, using ergonomic equipment and lifting techniques and alternating posture while caring for patients may reduce the burden.

Abdominal lifting, effleurage, and deep back massages effective in reducing pain during active phase of first stage labor

<p><strong>Background</strong> : Although childbirth is a natural process, the time of childbirth makes women feel afraid, anxious and anxious, thus affecting the labor process which results in prolonged labor and neonatal asphyxia. Where prolonged labor is a complication of the cause of maternal death which is the fifth largest in Indonesia. Labor pain can affect the condition of the mother in the form of victims, fear, worry and can cause stress. Stress can cause the uterine contractions to weaken and lead to prolonged labor.</p><p><strong>Objective</strong> : This study was to analyze the effectiveness of abdominal lifting, effleurage and deep back massage techniques in reducing pain during active phase of first stage labor.</p><p><strong>Method</strong> : This study used one-group pretest-posttest design method with a total sample of 30 Participants mother in labor. There were 3 groups that were given treatment, each group was given one massage technique. Change in pain was measured by a numerical pain scale. Testing variables using the Wilcoxon test, comparison of each intervention test performed using Kruskall Wallis.</p><p><strong>Result </strong>: There is a significant difference in pain scores before and after giving abdominal lifting massage with a value of p = 0.005 (<0.05). There was a significant difference in pain scores before and after giving effleurage massage with a value of p = 0.011 (p <0.05). There is a significant difference in pain scores before and after giving Deep Back Masaage with a value of p = 0.004 (p <0.005). There was no significant difference in pain scores after treatment between the three groups with a value of p = 0.080 (p> 0.05).</p><p><strong>Conclusion</strong> : abdominal lifting, effleurage, and deep back massage are effective in reducing the pain during active phase of first stage labor. There was no significant difference between the three massage techniques in reducing labor pain.</p>

Understanding Bench Press Biomechanics-Training Expertise and Sex Affect Lifting Technique and Net Joint Moments.

Mausehund, L and Krosshaug, T. Understanding bench press biomechanics-Training expertise and sex affect lifting technique and net joint moments. J Strength Cond Res 37(1): 9-17, 2023-The purpose of this study was to compare normalized net joint moments (NJMs), moment arms, and muscle activity in the bench press exercise between powerlifters and recreationally strength-trained lifters and between women and men. Thirty-four healthy adults, including 12 powerlifters (6 women and 6 men) and 22 recreational lifters (9 women and 13 men), performed a 6-8 repetition maximum set of the bench press, while elbow and shoulder NJMs and moment arms and electromyographic (EMG) activity of 6 upper extremity muscles were recorded. The results showed that training expertise and sex affected bench press technique substantially. Powerlifters applied a different bar path which impacted joint kinematics to a greater extent and joint kinetics to a lesser extent. Specifically, powerlifters had lower normalized peak elbow NJMs and shorter joint ROMs than recreational lifters ( p ≤ 0.05), yet no differences in normalized shoulder NJMs and muscle activity were observed. Women showed lower normalized mean shoulder NJMs, higher normalized peak elbow NJMs, and higher mean elbow to shoulder NJM ratios than men ( p ≤ 0.05). The muscle activity of the long head of the triceps brachii and the elbow to shoulder EMG ratio were higher, yet muscle activity of the sternocostal and abdominal head of the pectoralis major was lower for female than for male subjects ( p ≤ 0.05). In conclusion, powerlifters and men are more shoulder dominant when performing the bench press than recreational lifters and women, respectively. These findings will have implications for resistance training program design, expected training adaptations and bench press performance.

Load frequency control of time-delayed power system based on event-triggered communication scheme

In frequency regulation of power grids, conveying observations to controllers and obtaining control outputs depend greatly on communication and computation resources. Particularly for modern power system with an open communication network, the costs of communication and computation should not be ignored. This paper investigates an event-triggered based load frequency control for time-delayed power system with an open communication network. Based on the lifting technique in the sampled-data control theory, a new control scheme, using both a large sampling period and a maximized threshold parameter, is introduced to further lessen communication and computation costs while preserving a desired H∞ robust performance. The delay-dependent stability criterion of the proposed control scheme is less conservative, which takes fully the time delay, the sampling period, and the threshold parameter of event-triggered communication scheme into account. The proposed criterion is unified and can be transformed to the stability conditions of the existing research by setting different values of time delay, sampling and threshold parameter. Additionally, the usage of a large and aperiodic sampling period complies with the aperiodic updating characteristic of 2-4s in control signals in load frequency control scheme. Case studies based on a one-area power system, a two-area power system and an IEEE 39-bus benchmark test system are carried out. The simulation tests demonstrate that the proposed control scheme further reduces the communication and computation costs and ensures the load frequency control system stable operation with a preset H∞ robust performance.

The high impulse, palm lift technique for chest compression: Prospective, experimental, pilot study.

The classic technique of high quality chest compression (HQCC) during cardiopulmonary resuscitation (CPR) is based on the International Liaison Committee on Resuscitation (ILCOR) guidelines which specify that the rescuer's hands should maintain constant contact with the chest surface but should not lean upon it, in order to provide full chest recoil. Since end-tidal CO2 (EtCO2) values have been shown to be a reliable indicator of CPR quality, we examined a method where classic HQCC was modified by a high impulse and palm lifting (HIPL) technique which merged rapid forceful compression with disconnection of the rescuer's palm from the patient's sternum during the recoil phase. The object of the study was to detect any differences in HIPL EtCO2 values in comparison with those from classic HQCC. We report a prospective pilot study in which we compared EtCO2 readings achieved during 2min of classic HQCC technique with readings after implementing 2min of the HIPL technique during out-of-hospital CPR, provided by medical emergency response teams for cases of cardiac arrest. EtCO2 values obtained from16 cases who received HQCC followed by HIPL compressions showed a significant difference (p=0.037) between the two techniques. Mean±SD EtCO2 values after 2min of each technique were: HQCC: 18±9mmHg; HIPL: 27±11mmHg; followed by a further 2min of HQCC: 19±11mmHg. Linear regression showed that the differences in EtCO2 were associated with non - significant changes in ventilation rate (p=0.493) and chest compression rate (p=0.889). The results obtained suggest that modifying HQCC with the HIPL technique led to a significant increase in EtCO2 values in comparison with classic HQCC, indicating an improvement in circulation during CPR. We think that these encouraging early results warrant a larger multi - centre study of HIPL.

A Krein space-based approach to event-triggered [formula omitted] filtering for linear discrete time-varying systems

This paper is concerned with the problem of event-triggered H∞ filtering for linear discrete time-varying (LDTV) systems. Using the lifting technique, we firstly establish an equivalent relationship with a certain equivalent minimum problem of indefinite quadratic form subject to LDTV systems with non-uniform sampling periods. Then, based on Krein space projection and innovation analysis, sufficient and necessary conditions for the existence of desired filter are derived and a feasible solution is obtained in terms of Riccati recursions. Thus, an algorithm based on the time-update and event-update recursions is given for the implementation of event-triggered H∞ filtering. Different from some existing results, a new event-triggered H∞ filtering scheme is provided so that the estimation error can be completely decoupled from the event-triggered transmission error. Moreover, the new proposed Krein space approach is less conservative and more computational attractive than the existing methods based on recursive linear inequality matrix. Finally, a numerical example is given to illustrate the effectiveness of the proposed approach.

From Stoop to Squat: A Comprehensive Analysis of Lumbar Loading Among Different Lifting Styles.

Lifting up objects from the floor has been identified as a risk factor for low back pain, whereby a flexed spine during lifting is often associated with producing higher loads in the lumbar spine. Even though recent biomechanical studies challenge these assumptions, conclusive evidence is still lacking. This study therefore aimed at comparing lumbar loads among different lifting styles using a comprehensive state-of-the-art motion capture-driven musculoskeletal modeling approach. Thirty healthy pain-free individuals were enrolled in this study and asked to repetitively lift a 15 kg-box by applying 1) a freestyle, 2) a squat and 3) a stoop lifting technique. Whole-body kinematics were recorded using a 16-camera optical motion capture system and used to drive a full-body musculoskeletal model including a detailed thoracolumbar spine. Continuous as well as peak compressive, anterior-posterior shear and total loads (resultant load vector of the compressive and shear load vectors) were calculated based on a static optimization approach and expressed as factor body weight (BW). In addition, lumbar lordosis angles and total lifting time were calculated. All parameters were compared among the lifting styles using a repeated measures design. For each lifting style, loads increased towards the caudal end of the lumbar spine. For all lumbar segments, stoop lifting showed significantly lower compressive and total loads (−0.3 to −1.0BW) when compared to freestyle and squat lifting. Stoop lifting produced higher shear loads (+0.1 to +0.8BW) in the segments T12/L1 to L4/L5, but lower loads in L5/S1 (−0.2 to −0.4BW). Peak compressive and total loads during squat lifting occurred approximately 30% earlier in the lifting cycle compared to stoop lifting. Stoop lifting showed larger lumbar lordosis range of motion (35.9 ± 10.1°) than freestyle (24.2 ± 7.3°) and squat (25.1 ± 8.2°) lifting. Lifting time differed significantly with freestyle being executed the fastest (4.6 ± 0.7 s), followed by squat (4.9 ± 0.7 s) and stoop (5.9 ± 1.1 s). Stoop lifting produced lower total and compressive lumbar loads than squat lifting. Shear loads were generally higher during stoop lifting, except for the L5/S1 segment, where anterior shear loads were higher during squat lifting. Lifting time was identified as another important factor, considering that slower speeds seem to result in lower loads.

Low Back Pain-Behavior Correction by Providing Haptic Feedbacks: A Preliminary Investigation.

The activities performed by nurses in their daily activities involve frequent forward bending and awkward back postures. These movements contribute to the prevalence and development of low back pain (LBP). In previous studies, it has been shown that modifying their posture by education and training in proper lifting techniques decreases the prevalence of LBP. However, this education and training needs to be implemented daily. Hence, implementing the use of a wearable device to monitor the back posture with haptic feedback would be of importance to prevent LBP. This paper proposes a wearable device to monitor the back posture of the user and provide feedback when the participant is performing a possible hurtful movement. In this study, a group of participants was asked to wear the device while performing three of the most common activities performed by nurses. The study was divided into three sessions: In the first session, the participants performed the activities without feedback (baseline). During the second session, the participants received feedback from the wearable device (training) while performing the three tasks. Finally, for the third session, the participants performed the three tasks again, but the haptic feedback was turned off (validation). We found an improvement in the posture of more than 40% for the pitch (lateral bending) and roll (forward/backward bending) axes and 7% for the yaw (twisting) axis when comparing to the results from session 1 and session 2. The comparison between session 1 and session 3 showed an overall improvement of more than 50% for the pitch (lateral bending) and roll (forward/backward bending) axes and more than 20% for the yaw axis. These results hinted at the impact of the haptic feedback on the participants to correct their posture.

Cup product and Gerstenhaber bracket on Hochschild cohomology of a family of quiver algebras

We present a cup product formula on the Hochschild cohomology of a family of quiver algebras. We use the formula to determine the set of homogeneous non-nilpotent Hochschild cocycles and construct a canonical isomorphism between Hochschild cohomology modulo nilpotents and a subalgebra of that is not finitely generated. For some members of the family, we present the Gerstenhaber ideal of homogeneous nilpotent cocycles using homotopy lifting technique. We then determine their Hochschild cohomology modulo the weak Gerstenhaber ideal generated by nilpotent elements, thereby providing an answer to a question of Reiner Hermann.

Fibrational bisimulations and quantitative reasoning: Extended version

Abstract Bisimulation and bisimilarity are fundamental notions in comparing state-based systems. Their extensions to a variety of systems have been actively pursued in recent years, a notable direction being quantitative extensions. In this paper we enhance a categorical framework for such extended (bi)simulation notions. We use coalgebras as system models and fibrations for organizing predicates—following the seminal work by Hermida and Jacobs. Endofunctor liftings are crucial predicate-forming ingredients; the first contribution of this work is to extend several extant lifting techniques from particular fibrations to $\textbf {CLat}_\wedge $-fibrations over $\textbf {Set}$. The second contribution of this work is to introduce endolifting morphisms as a mechanism for comparing predicates between fibrations. We apply these techniques by deriving some known properties of the Hausdorff pseudometric and approximate bisimulation in control theory.

Perfect edge state transfer on cubelike graphs

Perfect (quantum) state transfer has been proved to be an effective model for quantum information processing. In this paper, we give a characterization of cubelike graphs having perfect edge state transfer (PEST, in short). By using a lifting technique, we show that every bent function, and some semi-bent functions as well, can produce some graphs having PEST. Some concrete constructions of such graphs are provided. Notably, using our method, one can obtain some classes of infinite graphs possessing PEST.

Exploring lumbar and lower limb kinematics and kinetics for evidence that lifting technique is associated with LBP

To investigate if lumbar and lower limb kinematics or kinetics are different between groups with and without a history of LBP during lifting. Secondly, to investigate relationships between biomechanical variables and pain ramp during repeated lifting. 21 LBP and 20 noLBP participants completed a 100-lift task, where lumbar and lower limb kinematics and kinetics were measured during lifting, with a simultaneous report of LBP intensity every 10 lifts. Lifts were performed in a laboratory setting, limiting ecological validity. The LBP group used a different lifting technique to the noLBP group at the beginning of the task (slower and more squat-like). Kinetic differences at the beginning included less peak lumbar external anterior shear force and greater peak knee power demonstrated by the LBP group. However, at the end of the task, both groups lifted with a much more similar technique that could be classified as more stoop-like and faster. Peak knee power remained greater in the LBP group throughout and was the only kinetic difference between groups at the end of the lifting task. While both groups lifted using a more comparable technique at the end, the LBP group still demonstrated a tendency to perform a slower and more squat-like lift throughout the task. Only one of 21 variables (pelvic tilt at box lift-off), was associated with pain ramp in the LBP group. Conclusions: Workers with a history of LBP, lift with a style that is slower and more squat-like than workers without any history of LBP. Common assumptions that LBP is associated with lumbar kinematics or kinetics such as greater lumbar flexion or greater forces were not observed in this study, raising questions about the current paradigm around 'safe lifting'.

After the Temporal Lifting Technique-What comes next?

The temporal lifting technique can provide lateral facial lifting when administering hyaluronic acid (HA)-based soft tissue fillers into the subdermal plane of the temple. However, the central facial oval is not influenced by this technique. To identify the safety and esthetic effectiveness of additional midfacial injection points (in addition to the temporal lifting technique) that can volumize the medial midface, lift the lateral face, and increase jawline contouring when included into a full-face injection algorithm. The patient records of nine consecutive patients (all females) with a mean age of 35.0 (8.4) years and a mean body mass index of 21.7 (2.4)kg/m2 were retrospectively analyzed after a full-face injection algorithm was performed using HA-based fillers. The additional injection points target the supraperiosteal plane of the medial zygomatic arch, the lateral infraorbital region, and the pyriform fossa using both needles and cannula. No adverse events were observed during the 6-month retrospective observational period. The volume of the medial midface increased, the volume of the lateral midface decreased, and the contour of the jawline improved; all effects reached a highly statistically significant level with p<0.001. Despite each individual injection is currently performed on a daily clinical basis the evaluated injection algorithm following the temporal lifting technique shows some evidence that it is safe and esthetically effective. Future studies will need to confirm the results presented herein in a larger sample and with objective outcome measures to guide safe and effective esthetic outcomes.