• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.48 no.5
• /
• pp.55-63
• /
• 2011

This paper describes new moving target detection technique combining two algorithms to detect targets and reject clutters in video frame images for surveillance system: One obtains the region of moving target using phase correlation method using $N{\times}M$ sub-block images in frequency domain. The other uses adaptive threshold using learning weight for extracting target candidates in subtracted image. The block region with moving target can be obtained using the characteristics that the highest value of phase correlation depends on the movement of largest image in block. This technique can be used in camera motion environment calculating and compensating camera movement using FFT phase correlation between input video frame images. The experimental results show that the proposed algorithm accurately detects target(s) with a low false alarm rate in variety environment using the receiver operating characteristics (ROC) curve.

• Journal of Biomedical Engineering Research
• /
• v.33 no.4
• /
• pp.184-193
• /
• 2012

Many studies have reported that housework done using household appliances may affect biomechanical characteristics of the musculoskeletal system. The purpose of this study was to investigate the effects of housework done using a pulsator washing machine on joints and muscles. We calculated joint torques and muscle strengths on the basis of an experimental/virtual three-dimensional motion analysis for six healthy females using the pulsator washing machine at different heights (H) and depths (D) of the inside drum (H (mm){\times}D (mm), Trial1: $962.5{\times}609.4$, Trial2: $962.5{\times}624.4$, Trial3: $982.5{\times}644.4$, Trial4: $995.5{\times}642.4$, Trial5: $1015.5{\times}677.4$). The joint torques and muscle strengths tended to be considerably different during torso flexion in the sagittal plane for all the trials. The maximum joint torques for the thoracic vertebra, left ankle, and right shoulder measured in Trial4 were significantly higher than those measured in the other trials (p < 0.05); in addition, those for the thoracic vertebra and both ankles measured in Trial5 were significantly higher than those measured in the other trials (p < 0.05). The maximum muscle strengths for the left trapezius muscle and both tibialis anterior muscles measured in Trial5 were significantly higher than those measured in the other trials (p < 0.05). These results indicate that housework done using a pulsator washing machine may affect joint torques and muscle strengths, and these effects are dependent on the height and/or depth of the inside drum of the pulsator washing machine.

• The Journal of the Korea Contents Association
• /
• v.10 no.2
• /
• pp.130-137
• /
• 2010

Light Drawing is a photographic technique which exposures are made at night or in a darkened room usually by moving a hand-held light source[1]. Due to the limitations of equipment and environment, users having difficulty in drawing a picture in 3D space. If user take a light drawing, they need a camera that have function and darkened environment. Alternative solution is that we can make a light drawing picture by using the computer drawing tool as in Photoshop. Nevertheless, this solution will let the User lose their interest in drawing because this solution cannot synchronize between the real action of human hand motion and the electronic input devices such as mouse and keyboard. This paper proposed a digital content that can make light drawing easier. We used a digital content that will facility Light Drawing easier. We can measure the light spot position by using the stereo camera. Based on the measured position of the light spot, we reproduce light drawing in virtual space by using drawing effect method.

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.11 no.4
• /
• pp.349-354
• /
• 2017

In this study, we proposed a design guideline of height-adjustable wash basin which is an assistive product for personal hygiene for persons with disability. We performed biomechanical assessments using both of conventional and prototype height adjustable wash basin. Total five elderly subjects (all male, age $68.6{\pm}4.3yrs.$, height $169.8{\pm}5.7cm$, weight $70{\pm}7.7kg$) participated for the assessment test. Each joint angles were measured by using a 3D motion capture system when subjects use wash basins, and the lumbar moment of each subjects was estimated based on a human body model. From the assessment results, a design guideline which has the range of the height from 652[mm] to 1162[mm] was proposed. Then additional assessment tests with five healthy subjects ($25.8{\pm}1.8yrs.$, $175.5{\pm}5.8cm$, $74{\pm}15.7kg$) were performed in order to verify effectiveness of the design guideline. The results showed a height-adjustable wash basin applied the proposed design guideline was effective to reduce the lumbar moment.

• PNF and Movement
• /
• v.17 no.3
• /
• pp.391-399
• /
• 2019

Purpose: This study investigated the three-dimensional moment values of the hip joint for subjects with artificial leg length alterations and subjects with unaltered leg lengths. Methods: Forty-two healthy adults (8 men, 34 women) participated in this study. The selected subjects were able to walk normally, had less than a 1 cm leg length discrepancy, and were instructed to wear shoes that fit their feet. The study participants performed 8 dynamic gait trails to measure the hip joint moment using a three-dimensional motion analysis system. Kinetic and dynamic three-dimensional gait analysis data were collected from infrared cameras, and a force plate was used to standardize the weight of each subject. Results: There were significant correlations between the differences in the leg length discrepancy during right extension, right flexion, right internal rotation, and left extension in hip joint moments (p<0.05). There were significant correlations between the differences in shoe conditions during left extension, right flexion, right extension, and right internal rotation in the hip moments (p<0.05). Conclusion: This study suggests that a leg length discrepancy can affect hip joint moment, which may further exacerbate musculoskeletal disorders, such as osteoarthritis in lower extremity joints. Therefore, further studies should be conducted to verify the impact of clinical interventions on differences in hip joint moment values to correct leg length discrepancies and prevent osteoarthritis in lower extremity joints.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.37 no.3
• /
• pp.267-274
• /
• 2009

Recently, UAVs (Unmanned Aerial Vehicles) are expected much as the Unmanned Systems for various missions. These missions are often based on the Vision System. Especially, missions such as surveillance and pursuit have a process which is carried on through the transmitted vision data from the UAV. In case of small UAVs, monocular vision is often used to consider weights and expenses. Research of missions performance using the monocular vision is continued but, actually, ground and target model have difference in distance from the UAV. So, 3D distance measurement is still incorrect. In this study, Mean-Shift Algorithm, Optical Flow and Subspace Method are posed to estimate the relative depth. Mean-Shift Algorithm is used for target tracking and determining Region of Interest (ROI). Optical Flow includes image motion information using pixel intensity. After that, Subspace Method computes the translation and rotation of image and estimates the relative depth. Finally, we present the results of this study using images obtained from the UAV experiments.

• Journal of the Society of Disaster Information
• /
• v.16 no.4
• /
• pp.813-823
• /
• 2020

Purpose: In order to maximize the stability and productivity of the work through simulation prior to high-risk facilities and high-cost work such as dismantling the facilities inside the reactor, we intend to use digital twin technology that can be closely controlled by simulating the specifications of the actual control equipment. Motion control errors, which can be caused by the time gap between precision control equipment and simulation in applying digital twin technology, can cause hazards such as collisions between hazardous facilities and control equipment. In order to eliminate and control these situations, prior research is needed. Method: Unity 3D is currently the most popular engine used to develop simulations. However, there are control errors that can be caused by time correction within Unity 3D engines. The error is expected in many environments and may vary depending on the development environment, such as system specifications. To demonstrate this, we develop crash simulations using Unity 3D engines, which conduct collision experiments under various conditions, organize and analyze the resulting results, and derive tolerances for precision control equipment based on them. Result: In experiments with collision experiment simulation, the time correction in 1/1000 seconds of an engine internal function call results in a unit-hour distance error in the movement control of the collision objects and the distance error is proportional to the velocity of the collision. Conclusion: Remote decomposition simulators using digital twin technology are considered to require limitations of the speed of movement according to the required precision of the precision control devices in the hardware and software environment and manual control. In addition, the size of modeling data such as system development environment, hardware specifications and simulations imitated control equipment and facilities must also be taken into account, available and acceptable errors of operational control equipment and the speed required of work.

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.9 no.2
• /
• pp.137-144
• /
• 2015

In this paper, we present an inertial sensor-based gait analysis system to measure and analyze lower-limb movements. We developed an integral AHRS(Attitude Heading Reference System) using a combination of rate gyroscope, accelerometer and magnetometer sensor signals. Several AHRS modules mounted on segments of the patient's body provide the quaternions representing the patient segments's orientation in space. And a method is also proposed for calculating three-dimensional inter-segment joint angle which is an important bio-mechanical measure for a variety of applications related to rehabilitation. To evaluate the performance of our AHRS module, the Vicon motion capture system, which offers millimeter resolution of 3D spatial displacements and orientations, is used as a reference. The evaluation resulted in a RMSE(Root Mean Square Error) of 1.08 and 1.72 degree in yaw and pitch angle. In order to evaluate the performance of our the gait analysis system, we compared the joint angle for the hip, knee and ankle with those provided by Vicon system. The result shows that our system will provide an in-depth insight into the effectiveness, appropriate level of care, and feedback of the rehabilitation process by performing real-time limb or gait analysis during the post-stroke recovery.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.14 no.3
• /
• pp.184-191
• /
• 2011

Preliminary design of a mooring system for a floating wave energy converter(WEC) is performed. A mooring line is designed to consist of two parts; the one is a chain in heavy weight laid on the seabed and linked to an anchor on the seabed and the other is a light weight chain suspended at a floater. A high weight chain laid on the seabed can contribute to mitigate dynamic energy propagated from top oscillation and decrease anchor weight and volume. Through a low weight chain suspended between a floater and seabed the WEC's function to produce energy from wave can be affected in minimum by the motion of a chain. The static and dynamic analyses for the designed mooring system were carried out to evaluate WEC system's safety. The present study shows that the designed gravity anchor moves horizontally due to the tension exerted on the anchor in the severe ocean environmental condition. The present mooring system should be redesigned to satisfy the safety requirements. The present study will be useful to predict the safety of the mooring system under ocean environment.

• Journal of Biomedical Engineering Research
• /
• v.27 no.6
• /
• pp.323-331
• /
• 2006

The purpose of this study was to investigate the effect of performing a cognitive task during treadmill walking on the stride rate variability. Ten university students(age $24.0{\pm}0.25$, height $172{\pm}3.1cm$, weight $66{\pm}5.3kg$) were participated in dual task experiments which consist of both walking alone and walking with a cognitive task. Two-back task was selected for the cognitive task since it did not have learning effect during the experimental procedure.3D motion analysis system was used to measure subject's position data by changing walking speed with 4.8, 5.6, 6.4, 6.8, and 7.2 km/hr. Stride rate was calculated by the time between heel contact and heel contact. Accuracy rate of a cognitive task during walking, coefficient of variance, allometric scaling methods and Fano factor were used to estimated the stride rate variability. As the walking speed increased, accuracy rate decreased and the logarithmic value of Fano factor increased which showed the statistical difference. Thus it can be concluded that the gait control mechanism is distracted by the secondary attention focus which is the cognitive task ie. two-back task. Further study is needed to clarify this by increasing the number of subject and experiment time.