• Journal of Biomedical Engineering Research
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• v.29 no.4
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• pp.323-328
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• 2008

A patient with respiratory disorders such as a sleep apnea is increasing as the obese patient increase on the modern society. Positive Airway Pressure (PAP) devices are used in curing patient with respiratory disorders and turn out to be efficacious for patients of 75%. However, these devices are required for evaluating their performance to improve their performance by the mechanical breathing simulator. Recently, the mechanical breathing simulator was studied by the real time feedback control. However, the mechanical breathing simulator by an open loop control was specially required in order to analyze the effect of flow rate and pressure after operating the breathing auxiliary devices. Therefore the aims of this study were to make the mechanical breathing simulator by a piston motion and a valve function from the characteristic test of valve and motor, and to duplicate the flow rate and pressure profiles of some breathing patterns: normal and three disorder patterns. The mechanical simulator is composed cylinder, valve, ball screw and the motor. Also, the characteristic test of the motor and the valve were accomplished in order to define the relationship between the characteristics of simulator and the breathing profiles. Then, the flow rate and pressure profile of human breathing patterns were duplicated by the control of motor and valve. The result showed that the simulator reasonably duplicated the characteristics of human patterns: normal, obstructive sleep apnea (OSA), mild hypopnea with snore and mouth expiration patterns. However, we need to improve this simulator in detail and to validate this method for other patterns.

• Nuclear Engineering and Technology
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• v.53 no.3
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• pp.825-832
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• 2021

A simulation-based approach is proposed to study the protective actions taken by residents during nuclear emergencies using cognitive findings. Human perception-based behaviors are not heavily incorporated in the evacuation study for nuclear emergencies despite their known importance. This study proposes a generic framework of perception-based behavior simulation, in accordance with the ecological concept of affordance theory and a formal representation of affordance-based finite state automata. Based on the generic framework, a simulation model is developed to allow an evacuee to perceive available actions and execute one of them according to Newton's laws of motion. The case of a shadow evacuation under nuclear emergency is utilized to demonstrate the applicability of the proposed framework. The illustrated planning algorithm enables residents to compute not only prior knowledge of the environmental map, but also the perception of dynamic surroundings, using widely observed heuristics. The simulation results show that the temporal and spatial dynamics of the evacuation behaviors can be analyzed based on individual perception of circumstances, while utilizing the findings in cognitive science under unavoidable data restriction of nuclear emergencies. The perception-based analysis of the proposed framework is expected to enhance nuclear safety technology by complementing macroscopic analyses for advanced protective measures.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2248-2253
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• 2005

Although the progress in bipedal walking is impressive in recent years, biped robots still require very high torque and can walk only for a short time interval with their internal batteries. Therefore, further research needs to be carried out to enhance walking efficiency of these robots. In order to achieve this goal, we attempt to imitate human walking with pelvis and waist joint rotations in the frontal plane. In order to investigate the effect of the pelvis and waist joint rotations in the frontal plane motion, we study the frontal plane model with a triangular structure made up of a waist joint and two hip joints. Through simulation, we show that the pelvis rotation can reduce the maximum torque and the control effort, and the waist joint rotation can reduce the trunk sway caused by the pelvis rotation. The combination of these two rotations makes the bipedal walking in the frontal plane more efficient.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.7
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• pp.43-50
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• 2002

This paper presents the new gait implementation of a biped robot with smooth walking using 3-dimensional continuous trunk motion and kick action of ankle joints. Trajectory generation ova trunk is performed not on a unit gait but on a whole walking interval. In applying kick action such as heel-touch or toe-off, varying coordinate system was employed for the simplification of the kinematic analysis. Desired ZMP (zero moment point) is also changed to implement the efficient kick action. As a result, balancing motion of the proposed gait was much more decreased than that of conventional one. Moreover, robot\\`s walking behavior is very smooth, natural and similar to the pace of a human. The walking experiment system is composed of eight AC servo motors and a DSP controller. The walking simulation and the experimental results are shown using the proposed new walking algorithm.

• The KIPS Transactions:PartB
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• v.8B no.5
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• pp.549-556
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• 2001

The general problems of recovering 3D for 2D imagery require the depth information for each picture element form focus. The manual creation of those 3D models is consuming time and cost expensive. The goal in this paper is to simplify the depth estimation algorithm that extracts the depth information of every region from monocular image sequence with camera translation to implement 3D video in realtime. The paper is based on the property that the motion of every point within image which taken from camera translation depends on the depth information. Full-search motion estimation based on block matching algorithm is exploited at first step and ten, motion vectors are compensated for the effect by camera rotation and zooming. We have introduced the algorithm that estimates motion of object by analysis of monocular motion picture and also calculates the averages of frame depth and relative depth of region to the average depth. Simulation results show that the depth of region belongs to a near object or a distant object is in accord with relative depth that human visual system recognizes.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.171.4-171
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• 2001

This paper proposes a method of human- robot interaction (HRI) using face directional gesture. A single CCD color camera is used to input face region, and the robot recognizes the face directional gesture based on the facial feature´s positions. One can give a command such as stop, go, left and right turn to the robot using the face directional gesture. Since the robot also has the ultra sonic sensors, it can detect obstacles and determine a safe direction at the current position. By combining the user´s command with the sensed obstacle configuration, the robot selects the safe and efficient motion direction. From simulation results, we show that the robot with HRI is more reliable for the robot´s navigation.

• The Journal of Korea Robotics Society
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• v.13 no.2
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• pp.86-91
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• 2018

This paper presents about design efforts of a human-sized quadruped robot leg for high energy efficiency, and verifications. One of the representative index of the energy efficiency is the Cost of Transport (COT), but increased in the energy or work done is not calculated in COT. In this reason, the input to the output energy efficiency should be also considered as a very important term. By designing the robot with customized motor housing, small rotational inertia, and low gear ratio to reduce friction, high energy efficiency was achieved. Squatting motion of one leg was performed and simulation results were compared to the experimental results for validation. The developed 50 kg robot can lift the weight up to 200 kg, and during squatting, it showed high energy efficiency. The robot showed 71% input to output energy efficiency in positive work. Peak current during squatting only appears to be 0.3 A.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.5
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• pp.472-478
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• 2011

The purpose of this study was to analyze the kinetic effect of Soft-$golf^{TM}$ instrument on the human body structure. To analyze the kinetic effect of Soft-$golf^{TM}$ instrument, Golf swing using Soft-$golf^{TM}$ instrument and regular golf instrument was captured. And then Upper limbs and lumbar joint torques was calculated via computer simulation. Five man participated this study. Subjects performed golf swing using a regular golf and Soft-$golf^{TM}$ instrument. Golf swing motion was captured using three position sensor, active infrared LED maker and force plate. Golf swing model was generated and simulated using ADAMS/LifeMOD program. As a results, joint torque during Soft-golf swing were lower than regular golf swing. Thus soft-golf swing have joint load lower than regular golf swing and contribute to reduce joint injury.

• Journal of Broadcast Engineering
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• v.8 no.3
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• pp.268-277
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• 2003

In this paper, we propose a new video watermarking method exploiting the human visual system (HVS) to find effective locations. in the video frames which make the watermark robust and imperceptible simultaneously. In particular, we propose a new HVS-optimized weighting map for hiding the watermark by considering HVS in three different aspects : frequency, spatial, and motion masking effects. The global masking map is modeled by combining the frequency masking, the spatial masking, and the motion masking. In this paper, we use a watermark which is generated by the bitwise exclusive-OR operation between a logo image and a random sequence. The amount of watermarks is weighted by a control parameter. Furthermore, we embed the watermark in the uncompressed video sequence for the general watermarking method available to various coding schemes. Simulation results show that the watermark is imperceptible and the proposed method is good for watermark capacity. It is also demonstrated that the proposed method is robust against various attacks, such as MPEG coding, MPEG re-encoding, and frame attacks.

• Korean Journal of Cognitive Science
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• v.10 no.3
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• pp.67-75
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• 1999

We investigated whether human could perceive the heading direction from the optic flow made from random dots and real images simulating the motion of the observer and objects. When an object moves across the focus of expansion(FOE) in random dot simulation. the observer perceived the focus of expansion biased toward the motion direction of the object. supporting the hypothesis that the direction repulsion is produced between the expansional and the horizontal planar motion components. With real image display observers tended to perceive one's heading direction biased toward the c center of the scene regardless of the direction and position of moving 0bcts. And it was observed that the deeper the depth of the background was the larger the judgment error was. These results suggest it is more likely that human depends on different cues than the optic flow when they perceive or judge one's heading direction in the real environment.