• Journal of the Korean Society of Clothing and Textiles
• /
• v.32 no.10
• /
• pp.1584-1594
• /
• 2008

This study was to research the characteristics of the body shape of Korean woman farmers by the major crops. Four hundred ninety-five Korean woman farmers from 9 different area such as Kumi, Damyang, Iksan, Injae, Chungju, Choongju, Haman, Whasung, and Whasoon volunteered for this study. Their major crops were the rice, the pepper, the water melon, the strawberry, the wild rocambole, the sweet persimmon, the grapes, the mushroom, and the chrysanthemums. Twelve body angles were measured from archived the somatotype photographs of the front, the side, and the back. Questionnaires of SF-36 and the farmer's symptom, and the farm-work related movements were surveyed. The results were as follows; 1. Farmers had lower health levels in physical role limit, pain, vitality, and physical function than other occupational workers. 2. Most farmers acted the high-risk ergonomics motions when they worked in the farm. 3. There were significantly different on the both shoulder angles, the hip tangential line slope, the hip breadth angel, in frontal ankle-knee angle, the bending back angle, the dropping breast slope, the abdominis media angle, under the abdominis media angle, the glutea angle, under the glutea angle, and the sideward knee angle(p<.05). 4. Farmers cultivating the low plants such as the water melon, the strawberry, and the wild rocambole showed more banded vertebralis and side knee angles. Farmers cultivating the red pepper showed the dropping the left shoulder and O shape legs. Farmers cultivating the fruit trees such as the sweet persimmon and the grapes showed the less banded side knee angles than other farmer groups. 5. On comparing the same age, farmers showed the older's body shape in earlier and much more than the old living in the city.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.37 no.5
• /
• pp.523-530
• /
• 2013

In this work, we study a heat transfer enhancement technology using fan-shaped small-scale fins. Fins having a thickness of 10 ${\mu}m$ move up-down by a pulsating flow. Owing to these motions, the heat transfer on a surface increases dramatically. The two-way FSI (fluid-structure interaction) method was applied for the analysis, and the analysis model was evaluated using a single fin model by comparing the experimental results. In summary, a maximum 40% increase in heat transfer capacity using a single and multiple small-scale fins was obtained in comparison with the results obtained without using fins. From this work, we believe that the proposed method can be a promising method for heat transfer enhancement in real applications.

• Journal of KIISE:Software and Applications
• /
• v.37 no.5
• /
• pp.354-362
• /
• 2010

This paper proposes a new method for a hierarchical analysis of human gait by dividing the motion into gait direction and gait posture using the tool of dynamic Bayesian network. Based on Factorial HMM (FHMM), which is a type of DBN, we design the Gait Motion Decoder (GMD) in a circular architecture of state space, which fits nicely to human walking behavior. Most previous studies focused on human identification and were limited in certain viewing angles and forwent modeling of the walking action. But this work makes an explicit and separate modeling of pedestrian pose and posture to recognize gait direction and detect orientation change. Experimental results showed 96.5% in pose identification. The work is among the first efforts to analyze gait motions into gait pose and gait posture, and it could be applied to a broad class of human activities in a number of situations.

• Journal of Digital Convergence
• /
• v.16 no.6
• /
• pp.197-204
• /
• 2018

The realistic Visual Effects using fluid simulation in 3D computer graphics are operated as important factors to improve the quality of images. The process of creating realistic motions of water, fire, explosion by controlling each property of fluid is called fluid simulation. In general, the creation of a fluid simulation concentrates on the main simulation work phase, however an effective method for initial set up is important for the main simulation work. The purpose of this study is to analyze the factors involved in the initial emission motion and shape of fluid and propose methods that can efficiently apply this into the initial set up. For the process of the research, first, problems are raised based on related researches, and second, two experiments, 'Dynamic Fluid Emitter Creation' and 'User Design Type Emission Velocity Solution', are conducted for more effective fluid simulation. Through this research, the effective fluid simulation of initial set up phase will be suggested through the user design-type emission control solutions.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.20 no.6
• /
• pp.46-53
• /
• 2016

It is required to predict a limit cycle amplitude controlled by system's nonlinear behavior as well as an eigen-frequency and initial growth rate of instabilities under the linear motions, in order to fully understand combustion instabilities in a lean premixed gas turbine combustor. Special focus of the current work is placed on the limit cycle amplitude prediction using flame describing function(FDF) where the ratio of a heat release fluctuation to a given flow perturbation is expressed as a function of frequency and amplitude. In this study, the CFD modeling work based on RANS is carried out to obtain FDF, which makes that the nonlinear thermo-acoustic model is successfully developed for predicting the limit cycle amplitude of the combustion instability.

• Korean Journal of Optics and Photonics
• /
• v.8 no.3
• /
• pp.189-193
• /
• 1997

Aspheric pick-up lenses are increasingly used in consumer products such as computer and multimedia, as their mass production has become possible owing to the injection molding process. However still much work needs to be done for more effective manufacture of aspheric lenses, one area of which is the in-line inspection of produced lenses. In this paper, we present a lateral-shearing interferometer that has specially been designed to have a high immunity to external vibration and atmospheric disturbance. The interferometer comprises four prisms. They are directly attached to each other using an immersion oil so that relative sliding motions between the prisms are allowed. Their relative displacement can readily generate necessary lateral-shearing and phase-shifting to determine the wavefront of the beam collimated by the lens under inspection. A special phase-measuring algorithm of arbitrary-bucket is adopted to compensate the phase-shifting error caused by the thickness reduction in the immersion oil. Zernike polynomial fitting has done for determinating quantitative aberration of aspheric pick-up lenses. The interferometer built in this work is robust to external mechanical vibration and atmospheric disturbance so that experimental results show that it has a repeatability of less than λ/100.

• Korean Journal of Applied Biomechanics
• /
• v.24 no.4
• /
• pp.391-397
• /
• 2014

The purpose of this work is to biomechanically study the effect of the one leg standing pose in yoga.. The work have been done through the evaluation for the left and right symmetry ability of one leg standing pose in the before and after yoga training for the 14 female yoga subject group (height: $164.3{\pm}4.4cm$, mass: $53.4{\pm}6.4kg$, year: $20.0{\pm}0.49yrs$) participated in this experiment. The motions of one leg standing pose were captured with Vicon system and the parameters were calculated with Visual-3D and Ground reaction force system. The results were as followed; - Front and backward COPsd did not show the significant difference, compared the before training with the after. - Left and right COPsd showed the significant difference (p<0.05), compared the before training with the after. - COP distance showed the significant difference (p<0.01), compared the before training with the after. - The asymmetry index of front and backward COPsd did not show the significant difference, compared the before training with the after. - The asymmetry index of left and right COPsd did not show the significant difference, compared the before training with the after. - The asymmetry index of COP distance showed the significant difference (p<0.01), compared the before training with the after. Therefore, the yoga training demonstrated the stable improvement in the one leg standing pose of inferior feet and the positive effect to the left and right symmetry ability.

• ETRI Journal
• /
• v.42 no.1
• /
• pp.54-66
• /
• 2020

Nowadays, the broad availability of cameras and embedded systems makes the application of computer vision very promising as a supporting technology for intelligent transportation systems, particularly in the field of vehicle tracking. Although there are several existing trackers, the limitation of using low-cost cameras, besides the relatively low processing power in embedded systems, makes most of these trackers useless. For the tracker to work under those conditions, the video frame rate must be reduced to decrease the burden on computation. However, doing this will make the vehicle seem to move faster on the observer's side. This phenomenon is called the fast motion challenge. This paper proposes a tracker called dynamic swarm particle (DSP), which solves the challenge. The term particle refers to the particle filter, while the term swarm refers to particle swarm optimization (PSO). The fundamental concept of our method is to exploit the continuity of vehicle dynamic motions by creating dynamic models based on PSO. Based on the experiments, DSP achieves a precision of 0.896 and success rate of 0.755. These results are better than those obtained by several other benchmark trackers.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.15 no.1
• /
• pp.61-68
• /
• 1991

The system such as railway bridge can be modelled as the restrained beam with intermediate supports. This kind of structures are subject to the moving load, which has a great effect on dynamic stresses and can cause sever motions, especially at high velocities. Therefore, to analyze the dynamic characteristics of the system due to the moving load is very important. In this paper, the governing equation of motion of a restrained beam subjected to the moving load is derived by using the Hamilton's principle. The orthogonal polynomial functions, which are trial functions and satisfying the geometric and dynamic boundary conditions, are obtained through simple procedure. The dynamic response of the system subjected to the moving loads is obtained by using the Galerkin's method and the numerical time integration technique. The numerical tests for various constraint, velocity and boundary conditions were preformed. Furthermore, the effects of mass of the moving load are studied in detail.

• Korean Journal of Applied Biomechanics
• /
• v.17 no.2
• /
• pp.187-196
• /
• 2007

The purpose of this study was to find the most effective movement pattern from three different types of preparatory movement(squat, countermovement and hopping) in sideward responsive propulsion task, which had the time constraint to complete the performance. 7 healthy subjects participated in left and right side movement task by an external signal, which required the subject to perform the task as fast as possible. Mechanical output and joint kinetics focusing on the lower extremities were analyzed. The results were as follows. In spite of the shortest duration in propulsive phase, the hopping condition showed no difference with other conditions in the work output done and take-off velocity. It resulted from the greatest power output generated during the propulsive phase. A significant difference was found for joint moment and joint power according to the movement conditions. The joint moment and joint power for the countermovement and hopping conditions were larger than those in the squat condition. This was speculated to be due to the extra power that could be generated by the pre-stretch of muscle in preparation for the propulsion. The hopping condition which had substantially more pre-stretch load in the preparatory eccentric phase produced considerably more power than countermovement condition in the propulsive concentric phase. Furthermore during the hopping a large amount of joint moment and joint power could be produced in a shorter time. Therefore it was deemed that the hopping movement is an effective type of preparatory movement which takes much more advantage of the pre-stretch than any other movement.