• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제10권2호
• /
• pp.703-722
• /
• 2016

Passive wireless devices have increasing civilian and military applications, especially in the scenario with wearable devices and Internet of Things. In this paper, we study indoor localization of a target equipped with radio-frequency identification (RFID) device in ultra-wideband (UWB) wireless networks. With known room layout, deterministic multipath components, including the line-of-sight (LOS) signal and the reflected signals via multipath propagation, are employed to locate the target with one transmitter and a single inaccurate receiver. A factor graph corresponding to the joint posterior position distribution of target and receiver is constructed. However, due to the mixed distribution in the factor node of likelihood function, the expressions of messages are intractable by directly applying belief propagation on factor graph. To this end, we approximate the messages by Gaussian distribution via minimizing the Kullback-Leibler divergence (KLD) between them. Accordingly, a parametric message passing algorithm for indoor passive localization is derived, in which only the means and variances of Gaussian distributions have to be updated. Performance of the proposed algorithm and the impact of critical parameters are evaluated by Monte Carlo simulations, which demonstrate the superior performance in localization accuracy and the robustness to the statistics of multipath channels.

• Smart Structures and Systems
• /
• 제24권1호
• /
• pp.95-110
• /
• 2019

The semi-active impact damper (SAID) is proposed to improve the damping efficiency of traditional passive impact dampers. In order to investigate its damping mechanism and vibration control effects on realistic engineering structures, a 20-story nonlinear benchmark building is used as the main structure. The studies on system parameters, including the mass ratio, damping ratio, rigid coefficient, and the intensity of excitation are carried out, and their effects both on linear and nonlinear indexes are evaluated. The damping mechanism is herein further investigated and some suggestions for the design in high-rise buildings are also proposed. To validate the superiority of SAID, an optimal passive particle impact damper ($PID_{opt}$) is also investigated as a control group, in which the parameters of the SAID remain the same, and the optimal parameters of the $PID_{opt}$ are designed by differential evolution algorithm based on a reduced-order model. The numerical simulation shows that the SAID has better control effects than that of the optimized passive particle impact damper, not only for linear indexes (e.g., root mean square response), but also for nonlinear indexes (e.g., component energy consumption and hinge joint curvature).

• 제어로봇시스템학회논문지
• /
• 제17권7호
• /
• pp.685-696
• /
• 2011

An efficient laparoscope manipulator robot was designed to automatically control the position of laparoscope via a passive joint on end-effector position. The end position of the manipulator is controlled to have corresponding velocity defined in the global coordinate space using laparoscopic visual information. Desired spatial position of laparoscope was derived from detected positions of surgical instrument tips, then the clinical viewing plane was moved by visual servoing task. The laparoscope manipulator is advantageous for automatically maintaining clinically important views in the laparoscopic image without any additional operator. A laparoscope is mounted to a holder which is linked to four degree of freedom manipulator via universal joint-type passive rings connection. No change in the design of laparoscope or manipulator is necessary for its application to surgery assistant robot system. Expanded working space and surgical efficiency were accomplished by implementing slant linking structure between laparoscope and manipulator. To ensure reliable positioning accuracy and controllability, the motion of laparoscope in an abdominal space through trocar was inspected using geometrical analysis. A designed laparoscope manipulating robot system can be easily set up and controlled in an operation room since it has a few subsidiary devices such as a laparoscope light source regulator, a control PC, and a power supply.

• 제어로봇시스템학회논문지
• /
• 제16권9호
• /
• pp.833-839
• /
• 2010

In this paper, a novel 1 DOF hand rehabilitation robot is proposed in consideration of ADL training for stroke patients. To perform several ADL trainings, the proposed robot can move the thumb part and the part of 4 fingers simultaneously and realize the full ROM (Range of Motion) in grasp. Based on these characteristics, the proposed robot realizes several types of grasp such as cylindrical grasp, lateral grasp, and pinch grasp by using a passive revolute joint that can change the thumb movement direction. The movement of the thumb is driven by a cable mechanism and the part of 4 fingers is moved by a four-bar linkage mechanism.

• 로봇학회논문지
• /
• 제11권4호
• /
• pp.193-204
• /
• 2016

This paper presents an anthropomorphic finger prosthesis for amputees whose proximal phalanx is mutilated. The finger prosthesis to be proposed is able to make the amputees to perform the natural motion such as flexion/extension as well as self-adaptive grasping motion as if normal human finger does. The mechanism of finger prosthesis with three degrees-of-freedom (DOFs) consists of two five-bar and one four-bar linkages. Two passive components composed of torsional spring and mechanical stopper and only one active joint are employed in order to realize an underactuation. Each passive component is installed into the five-bar linkage. In order to activate the finger prosthesis, it is required for the user to flex and extend the remaining proximal phalanx on the metacarpophalangeal (MCP) joint, not an electric motor. Thus the finger prosthesis conducts not only the natural motion according to his/her intention but also the grasping motion through the deformation of springs by the object for human finger-like behavior. In order to reveal the operation principle of the proposed mechanism, kinematic analysis is performed for the linkage design. Finally both simulations and experiments are conducted in order to reveal the design feasibility of the proposed finger mechanism.

• 한국전문물리치료학회지
• /
• 제9권2호
• /
• pp.133-144
• /
• 2002

The purpose of this study was to establish reliability of the Tone Assessment Scale (TAS) translated into Korean in patients with stroke. The TAS consists of resting posture, response to passive movement, and associated reaction to active effort. Fifteen patients (14 males, 1 female) were examined by two raters. Surface electromyography (EMG) data at elbow flexor muscle and joint excursion were collected from 6 patients. To identify the correlation between muscle activity and angular changes of elbow muscle, Pearson product moment correlation was used. The inter-rater and intra-rater reliability of the TAS ranged from very good to good (K/Kw=.61~1.00 for intra-rater and K/Kw=.73~1.00 for intra-rater comparisons) in the sections of resting posture and associated reaction. However, in the section of response to passive movement, the reliability coefficients ranged from very good to fair (Kw=.29~1.00). In the 11th item, correlation between EMG ratio of elbow flexor and angular changes of elbow joint showed statistically strong positive relationship (r=.94, p<.05). These results indicate that the TAS is selectively reliable in the sections of resting posture and associated reaction.

• Physical Therapy Rehabilitation Science
• /
• 제8권3호
• /
• pp.152-157
• /
• 2019

Objective: We aimed to investigate differences of range of motion in measuring shoulder internal rotation (IR) and external rotation (ER) resulting from posture change in manual scapular stabilization in prone, hook-lying, sitting, and standing positions in healthy young adults. Design: Cross-sectional study. Methods: This study included healthy young adults who agreed to participate after a thorough explanation about the study purpose and methods. A clinometer was used to measure shoulder rotation. Measurements of shoulder rotation according to postural change were performed in prone, hook-lying, sitting, and standing positions. The repeated measures analysis of variance was used to compare between-group differences in postural change. Results: The lower the posture, the greater the average value of IR angle. In contrast, the higher the posture, the greater the average value of the external rotation angle. In active and passive IR with posture change, there was difference in average value but with no statistical significance. In active and passive ER, there was a statistically significant difference between prone and sitting, prone and standing, hook-lying and sitting, hook-lying and standing, and sitting and standing position (p<0.05). Conclusions: Our findings suggest that postural change should be considered in order to increase the strength or range of motion of the internal and external rotation of the patient's shoulder joint.

• Journal of Oral Medicine and Pain
• /
• 제20권1호
• /
• pp.159-169
• /
• 1995

The purpose of this study was investigating the effects of pivot splint on width of the temporomandibular joint space in order to get the basic data for clinical applications. Pivot splint could be used for treating the patients with temporomandibular disorders, especially for chronic closed lock which would not be reduced by joint manipulation or with other methods. So it is necessary to have a lot of underlying data for using pivot splint, but there is few available reports related to mechanical principle or clinical results of the splint. Healthy twenty dental students wee collected for this study and pivot splint with 2.5mm high right-side pivot was used. Next, transcanial projection was taken and width of joint space at there mandibular positions were measured : habitual occlusion position, clenching position with splint, and clenching position with splint and mandibular force. The data were processed with SAS statistical program. The obtained results were as follows : 1. Ipsilateral posterior joint space width was increased on clenching the pivot splint, but joint space widths of contralateral side were not significantly changed. 2. Superior and posterior joint space width were increased on clenching the pivot splint with mandibualr force on both ipsilateral and contralateral side. 3. Ipsilateral joint space widths were not significantly changed from habitual occlusion position to clenching the pivot splint with active mandibular force, but in case of with passive mandibular force, posterior joint space width was significantly increased. 4. Correlationships between mandibular positions were more significant at anterior joint space than at superior or posterior joint space. But the correlation between clenching and clenching with mandibular force was significant at all the three joint space.

• Journal of Mechanical Science and Technology
• /
• 제16권8호
• /
• pp.1079-1088
• /
• 2002

Motivated by the dynamic output feedback passification results, point-to-point control laws for an elastic joint robot are presented when only the position measurements are available. The proposed method makes a parallel connection of the robot system and an input-dimensional linear system which obtains the effect of the desired differentiators. It is shown that the closed-loop nonlinear robot system can be rendered output strictly passive and the regulation of the system is achieved in the end. Robustness analysis is also given with regard to uncertainties on the robot parameters. Performance of the proposed control law is illustrated in the simulation studies of a manipulator with three revolute elastic joints.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 1994년도 가을 학술발표회 논문집
• /
• pp.149-157
• /
• 1994

In this study two dimensional visco-plastic finite element model capable of handling the multi-step excavation was developed for investigating the effect of excavation support sequences on the behavior of underground openings in the jointed rock mass. First, the finite element model which is capable of handling the multi-step excavation is developed and verified. And then the model is combined with visco-plastic joint model. Ubiquitous joint pattern was considered in the model and joint properties in cach set were assumed to be indentical. Passive, full-grouted rockbolts were cosidered in the numerical model. The visco-plastic deformations of joints and rockbolts were assumed to be governed by Mohr-Conlomb and von Mises yield criteria, respectively. With the ability of removing elements, the model can simulate the multi-step excavation-suppport sequences. The reliability and applicability of the model to the stability analysis for the underground excavation in pratice was checked by simulating the behavior of underground crude oil storage caverns under construction.