bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis on the stress of the bone surrounding mini-implant with different diameters and lengths under torque
Authors: Lu Yingjuan , Chang Shaohai , Ye Jiantao , Ye Yushan , Yu Yansong 
Published: August 2015

Abstract The purpose of this study is to compare the stress of the bone around the mini-implant under the two kinds of force: the composite force which contains torque and traditional single force. There were 96 finite element models formed by the combination of mini-implant and bone, with diameters of 1.2 mm, 1.6 mm, 2.0 mm and corresponding length being 6 mm, 8 mm, 10 mm, 12 mm, respectively. Each size corresponded to 8 models. Group SF (each size n=4) was loaded with 200 g single force, while Group CF (each size n=4) was loaded with composite force which contained 6N mm torque and 200 g single force. The maximum equivalent stress (Max EQS) of the bone surrounding mini implant with different loading directions was calculated, and the relationship of force direction, diameter and length was also evaluated. The Max EQS of Group CF was higher than that of Group SF. The effect of force direction on the stress was related to the diameter of mini implant, but had nothing to do with its length. The Max EQS of the cortical bone around mini implant in Group CF was higher (P<0.05) than that in Group SF. In contrast, there was no significant difference (P>0.05) between Group SF and Group CF in terms of bone stress when the diameter of mini implant was 1.6 mm or 2.0 mm. In our study, it is demonstrated that the diameter of mini-implant is better to be larger than 1.2 mm when a mini-implant is used in a torque control of tooth. The impact of this feature in the clinical setting needs to be verified.
Study on loss mechanism of SMA tracheal stent subjected to cough excitation
Authors: Zhu Zhiwen , Li Xinmiao , Xu Jia 
Published: August 2015

Abstract A kind of Ti-Ni shape memory alloy (SMA) hysteretic nonlinear model is developed, and the loss mechanism of a SMA tracheal stent subjected to cough excitation is studied in this paper. Nonlinear differential items are introduced to express the hysteretic phenomena of Ti-Ni SMA, and the fitting effect of the SMA constitutive model on the experimental data is proved by the partial least-square regression method. The nonlinear dynamic model of a Ti-Ni SMA tracheal stent subjected to cough excitation is developed, and the system’s dynamic response is obtained. The numerical results show that the system’s vibration is little in weak excitation, becomes large with the increase of the stochastic excitation, and finally becomes little again with the further increase of the stochastic excitation; the stochastic resonance phenomenon occurs in the process, which may cause stent fracture or loss.
Preliminary study on verifying the detection of gait intention based on knee joint anterior displacement of gait slopes
Authors: Yu Changho , Kang Seung Rok , Yang Giltae , Hong Chul Un , Lee Hyung Jong , Oh Do Young , Kwon Tae Kyu 
Published: August 2015

Abstract This study investigated the feasibility of the Infrared (IR) sensor-based walking aids for detecting the gait intention. To compensate for the defects of Force Sensing Resistors (FSRs) or force sensors, such as the velocity control problem on gait slopes, we used IR sensors to investigate knee joint anterior displacement in order to recognize the gait intention. We also measure leg muscle activities and foot pressure, in order to verify our investigation. We placed two IR sensors on the rollator center to sense left and right leg walking intentions. We took EMG signals of four leg muscles, and analyzed them. Foot pressure analysis parameters were the measured force and mean pressure. We conducted experiments on twenty young healthy adults. The results show that knee joint anterior displacement increases according to gait slope and velocity. We confirm similar results of knee joint anterior displacement through the IR sensors.
Research on musculoskeletal model of elbow joint for evaluating the feasibility of FES
Authors: Wang Shengxin , Gao Yongsheng , Liu Gangfeng , Xiao Feiyun , Zhao Jie 
Published: August 2015

Abstract Tremor usually occurs in a patient’s upper limb with a roughly sinusoidal profile. Understanding the inner mechanism of the involuntary movement is fundamental to improving tremor suppression treatments. Therefore, the musculoskeletal model of the elbow joint was developed in this study. Initially, healthy subjects were selected to simulate tremor and the tremulous data was collected with the purpose of sparing patients from fatigue. With the recorded joint angle and surface EMG (sEMG), the model was calibrated to subjects by optimization approach. The activation derived from the electric pulse was employed to drive the tuned model and the model’s output was compared with the angle predicted by the EMG-driven musculoskeletal model. The results demonstrated that the performance of the calibrated model was improved by a smaller normalized root mean square error and a higher coefficient of determination compared with the no-tuned model. There was no significant difference between the angles estimated by the tuned model activated by the electric pulse and muscle excitation. It indicates that neural activation could be replaced by the electric pulse to excite the limbs for desired angle. Therefore, the study presents a good way to evaluate the feasibility of Functional Electric Stimulation to suppress tremor.
Influence of pelvic asymmetry and idiopathic scoliosis in adolescents on postural balance during sitting
Authors: Jung Ji-Yong , Cha Eun-Jong , Kim Kyung-Ah , Won Yonggwan , Bok Soo-Kyung , Kim Bong-Ok , Kim Jung-Ja 
Published: August 2015

Abstract The effects of pelvic asymmetry and idiopathic scoliosis on postural balance during sitting were studied by measuring inclination angles, pressure distribution, and electromyography. Participants were classified into a control group, pelvic asymmetry group, scoliosis group, and scoliosis with pelvic asymmetry and then performed anterior, posterior, left, and right pelvic tilting while sitting on the unstable board for 5 seconds to assess their postural balance. Inclination and obliquity angles between the groups were measured by an accelerometer located on the unstable board. Pressure distribution (maximum force and peak pressure) was analyzed using a capacitive seat sensor. In addition, surface electrodes were attached to the abdominal and erector spinae muscles of each participant. Inclination and obliquity angles increased more asymmetrically in participants with both pelvic asymmetry and scoliosis than with pelvic asymmetry or scoliosis alone. Maximum forces and peak pressures of each group showed an asymmetrical pressure distribution caused by the difference in height between the left and right pelvis and curve type of the patients’ spines when performing anterior, posterior, left, and right pelvic tilting while sitting. Muscle contraction patterns of external oblique, thoracic erector spinae, lumbar erector spinae, and lumbar multifidus muscles may be influenced by spine curve type and region of idiopathic scoliosis. Asymmetrical muscle activities were observed on the convex side of scoliotic patients and these muscle activity patterns were changed by the pelvic asymmetry. From these results, it was confirmed that pelvic asymmetry and idiopathic scoliosis cause postural asymmetry, unequal weight distribution, and muscular imbalance during sitting.
Finite element analysis of stress distribution in four different endodontic post systems in a model canine
Authors: Chen Aijie , Feng Xiaoli , Zhang Yanli , Liu Ruoyu , Shao Longquan 
Published: August 2015

Abstract To investigate the stress distribution in a maxillary canine restored with each of four different post systems at different levels of alveolar bone loss. Two-dimensional finite element analysis (FEA) was performed by modeling a severely damaged canine with four different post systems: CAD/CAM zirconia, CAD/CAM glass fiber, cast titanium, and cast gold. A force of 100 N was applied to the crown, and the von Mises stresses were obtained. FEA revealed that the CAD/CAM zirconia post system produced the lowest maximum von Mises stress in the dentin layer at 115.8 MPa, while the CAD/CAM glass fiber post produced the highest stress in the dentin at 518.2 MPa. For a severely damaged anterior tooth, a zirconia post system is the best choice while a cast gold post ranks second. The CAD/CAM glass fiber post is least recommended in terms of stress level in the dentin.
Coupled motion of cervical spine in three level hybrid constructs
Authors: Liao Zhenhua , Pu Ting , Gu Hongsheng , Liu Weiqiang 
Published: August 2015

Abstract To compare the biomechanical characters of three-level anterior cervical fusion and hybrid constructs by measuring coupled motion changes of the cervical spine, Eighteen adult human cadaveric cervical spines were biomechanically investigated under eccentric displacement control in lateral bending and axial rotation by measuring vertebral motion (X, Y, Z -axis).The 3DPD condition displayed similar coupled motion compared to the intact condition both in lateral bending and in axial rotation, while the 3PDP condition was similar only in lateral bending. However, the coupled motion of the cervical spine under 3P conditions markedly changed in both lateral bending and axial rotation. Considering the coupled motion characteristics, the 3DPD hybrid construct is biomechanically advantageous in three types of reconstructions (3DPD, 3PDP, 3P).
Robot-assisted humanized passive rehabilitation training based on online assessment and regulation
Authors: Pan Lizheng , Song Aiguo , Duan Suolin , Xu Baoguo 
Published: August 2015

Abstract Robot-assisted rehabilitation has been developed and proved effective for motion function recovery. Humanization is one of the crucial issues in the designing of robot-based rehabilitation system. However, most of the previous investigations focus on the simplex position control when comes to the control system design of robot-assisted passive training, and pay little attention to the dynamic adjustment according to the patient’s performances. This paper presents a novel method to design the passive training system using a developed assessing-and-regulating section to online assess the subject’s performances. The motion regulating mechanism is designed to dynamically adjust the training range and motion speed according to the actual performances, which is helpful to improve the humanization of the rehabilitation training. Moreover, position-based impedance control is adopted to achieve compliant trajectory tracking movement. Experimental results demonstrate that the proposed method presents good performances not only in motion control but also in humanization.
Experiments and kinematics analysis of a hand rehabilitation exoskeleton with circuitous joints
Authors: Zhang Fuhai , Fu Yili , Zhang Qinchao , Wang Shuguo 
Published: August 2015

Abstract Aiming at the hand rehabilitation of stroke patients, a wearable hand exoskeleton with circuitous joint is proposed. The circuitous joint adopts the symmetric pinion and rack mechanism (SPRM) with the parallel mechanism. The exoskeleton finger is a serial mechanism composed of three closed-chain SPRM joints in series. The kinematic equations of the open chain of the finger and the closed chains of the SPRM joints were built to analyze the kinematics of the hand rehabilitation exoskeleton. The experimental setup of the hand rehabilitation exoskeleton was built and the continuous passive motion (CPM) rehabilitation experiment and the test of human-robot interaction force measurement were conducted. Experiment results show that the mechanical design of the hand rehabilitation robot is reasonable and that the kinematic analysis is correct, thus the exoskeleton can be used for the hand rehabilitation of stroke patients.
Effect of vibration on muscle strength imbalance in lower extremity using multi-control whole body vibration platform
Authors: Yu Chang Ho , Seo Shin Bae , Kang Seung Rok , Kim Kyung , Kwon Tae Kyu 
Published: August 2015

Abstract This study shows the improvement of muscle activity and muscle strength imbalance in the lower extremities through independent exercise loads in vibration platform. Twenty females of age 20 participated in this study. The subjects were divided into WBV group, with more than 10% of muscle strength imbalance between left and right the lower extremities, and control group, with less than 10% of muscle strength imbalance between left and right the lower extremities. As the prior experiment showed, different exercise postures provide different muscular activities. As a result, the highest muscular activity was found to be in the low squat posture. Therefore, the LS posture was selected for the exercise in this experiment. Vibration intensities were applied to dominant muscle and non-dominant muscle, and the vibration frequency was fixed at 25Hz for the WBV group. The control group was asked to perform the same exercise as the WBV group, without stimulated vibration. This exercise was conducted for a total of 4 weeks. As a result, the WBV group which showed an average deviation of 16% before the experiment, tended to decrease approximately to 5%. In this study, vibration exercise using load deviation is shown to be effective in improving the muscle strength imbalance.
The effect of toe marker placement error on joint kinematics and muscle forces using OpenSim gait simulation
Authors: Xu Hang , Merryweather Andrew , Bloswick Donald , Mao Qi , Wang Tong 
Published: August 2015

Abstract Marker placement can be a significant source of error in biomechanical studies of human movement. The toe marker placement error is amplified by footwear since the toe marker placement on the shoe only relies on an approximation of underlying anatomical landmarks. Three total knee replacement subjects were recruited and three self-speed gait trials per subject were collected. The height variation between toe and heel markers of four types of footwear was evaluated from the results of joint kinematics and muscle forces using OpenSim. The reference condition was considered as the same vertical height of toe and heel markers. The results showed that the residual variances for joint kinematics had an approximately linear relationship with toe marker placement error for lower limb joints. Ankle dorsiflexion/plantarflexion is most sensitive to toe marker placement error. The influence of toe marker placement error is generally larger for hip flexion/extension and rotation than hip abduction/adduction and knee flexion/extension. The muscle forces responded to the residual variance of joint kinematics to various degrees based on the muscle function for specific joint kinematics. This study demonstrates the importance of evaluating marker error for joint kinematics and muscle forces when explaining relative clinical gait analysis and treatment intervention.
Effects of custom-made insoles on idiopathic pes cavus foot during walking
Authors: Choi Jung-Kyu , Cha Eun-Jong , Kim Kyung-Ah , Won Yonggwan , Kim Jung-Ja 
Published: August 2015

Abstract From a subject group of pes cavus, the purpose of this study was to evaluate the biomechanical characteristics of lower limbs, based on plantar foot pressure and electromyography (EMG) activities, by the effects on two kind of custom-made insoles. Ten individuals among thirty females with a clinical diagnosis of idiopathic pes cavus (mean age (SD): 22.3 (0.08) years) were selected for the study. The plantar foot pressure data and EMG activities of four lower limb muscles were collected, when subjects walked on a treadmill, under three different experimental conditions. The plantar foot pressure data was analyzed, after the bilateral foot was divided into three areas of masks and into four sections of stance phase, to compare plantar foot pressure. The EMG activities were analyzed for integrated EMG (IEMG) value. The results show that plantar foot pressure concentrated in particular parts is decreased by custom-made insoles. In the case of EMG, all the muscle activities decreased significantly. The custom-made insoles dispersed pressure concentrated by the higher medial longitudinal arch and improved the efficient use of muscles. In particular, the extension structure in the forefoot of custom-made insoles was more efficient for pes cavus. Therefore, it could help patients to walk, by offering support to prevent the disease of pes cavus deformity, and to relieve the burden and fatigue in the lower limbs on gait.
Evaluation of joint moment patterns of a wearable walking assistant robot: Experimental and simulation analyses
Authors: Kang Ho Chul , Lee Ju Hwan , Kim Sung Min 
Published: August 2015

Abstract This study analyzes the moment of human main joints (knee and hip) for developing a wearable walking assistant robot. Experiments were performed on two steps to analyze motions. Three healthy males with no neural and musculoskeletal disorders volunteered to participate in this study. In the step up test, the maximum moment was 0.98±0.05 Nm/kg for the knee and 0.52±0.04 Nm/kg for the hip. In the sit-to-stand test, the maximum moment was 0.88±0.06 Nm/kg for the knee and 0.44±0.04 Nm/kg for the hip. The moment of the hip was significantly higher than the knee. In addition, the motion analysis results were compared with proven validity and inverse dynamics analysis results. Experimental results showed that there was no significant difference in the absolute value or pattern. For the step up motion, after wearing Powered Gait Orthosis (PGO), the hip joint torque value (1.22 Nm/kg) was about 1.3 times greater than the knee joint torque value (0.96 Nm/kg). It indicates that the step up motion requires more power from the hip joint than the knee joint. Moreover, there was a significant torque value difference for before and after wearing the device.
Biomechanical modeling and load-carrying simulation of lower limb exoskeleton
Authors: Zhu Yanhe , Zhang Guoan , Zhang Chao , Liu Gangfeng , Zhao Jie 
Published: August 2015

Abstract This paper introduces novel modern equipment—a lower extremity exoskeleton, which can implement the mutual complement and the interaction between human intelligence and the robot’s mechanical strength. In order to provide a reference for the exoskeleton structure and the drive unit, the human biomechanics were modeled and analyzed by LifeModeler and Adams software to derive each joint kinematic parameter. The control was designed to implement the zero-force interaction between human and exoskeleton. Furthermore, simulations were performed to verify the control and assist effect. In conclusion, the system scheme of lower extremity exoskeleton is demonstrated to be feasible.
Preliminary evaluation of a virtual reality dental simulation system on drilling operation
Authors: Wang Dangxiao , Zhao Siming , Li Teng , Zhang Yuru , Wang Xiaoyan 
Published: August 2015

Abstract To evaluate the fidelity of the iDental system and investigate its utility and performance on simulated drilling operations, user studies consisting of objective and subjective evaluations were performed. A voxel-based drilling simulation sub-system in the iDental system was employed for evaluation. Twenty participants were enrolled to take part in the experiments and were divided into two groups: novice and resident. A combined evaluation method including objective and subjective methods was employed. The objective evaluation included two dental drilling tasks: caries removal operation and pulp chamber opening operation. In the subjective method, participants were required to complete a questionnaire to evaluate the fidelity of the system after the operation task. Based on the structured global assessment scales in the questionnaire, the average subjective evaluation scores of the proposed metrics were greater than 4.5, demonstrating that the system operated above medium fidelity. Dentists expressed great interest and positive attitudes toward the potential of the iDental system. The objective evaluation data including time spent and the volume of removed healthy and carious tissue were obtained. Although no significant differences could be found between the two groups, the volume of removed caries and the depth of pulp chamber insertion manifested small standard deviations. Evaluation results illustrated that dentists were willing to use the virtual reality training system. Several future research topics were identified, including increasing the task difficulty, improving the system fidelity and introducing appropriate finger rest points.
New equivalent-electrical circuit model and a practical measurement method for human body impedance
Authors: Chinen Koyu , Kinjo Ichiko , Zamami Aki , Irei Kotoyo , Nagayama Kanako 
Published: August 2015

Abstract Human body impedance analysis is an effective tool to extract electrical information from tissues in the human body. This paper presents a new measurement method of impedance using armpit electrode and a new equivalent circuit model for the human body. The lowest impedance was measured by using an LCR meter and six electrodes including armpit electrodes. The electrical equivalent circuit model for the cell consists of resistance R and capacitance C. The R represents electrical resistance of the liquid of the inside and outside of the cell, and the C represents high frequency conductance of the cell membrane. We propose an equivalent circuit model which consists of five parallel high frequency-passing CR circuits. The proposed equivalent circuit represents alpha distribution in the impedance measured at a lower frequency range due to ion current of the outside of the cell, and beta distribution at a high frequency range due to the cell membrane and the liquid inside cell. The calculated values by using the proposed equivalent circuit model were consistent with the measured values for the human body impedance.
Efficient snoring and breathing detection based on sub-band spectral statistics
Authors: Sun Xiang , Kim Jin Young , Won Yonggwan , Kim Jung-Ja , Kim Kyung-Ah 
Published: August 2015

Abstract Snoring, a common symptom in the general population may indicate the presence of obstructive sleep apnea (OSA). In order to detect snoring events in sleep sound recordings, a novel method was proposed in this paper. The proposed method operates by analyzing the acoustic characteristics of the snoring sounds. Based on these acoustic properties, the feature vectors are obtained using the mean and standard deviation of the sub-band spectral energy. A support vector machine is then applied to perform the frame-based classification procedure. This method was demonstrated experimentally to be effective for snoring detection. The database for detection included full-night audio recordings from four individuals who acknowledged having snoring habits. The performance of the proposed method was evaluated by classifying different events (snoring, breathing and silence) from the sleep sound recordings and comparing the classification against ground truth. The proposed algorithm was able to achieve an accuracy of 99.61% for detecting snoring events, 99.16% for breathing, and 99.55% for silence.