• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.388-394
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• 2005

Recently, the authors have developed a method for real-time dynamics of multibody systems, which combines a semi-recursive formulation to derive the equations of motion in dependent relative coordinates, along with an augmented Lagrangian technique to impose the loop closure conditions. The following numerical integration procedures, which can be grouped into the so-called structural integrators, were tested : trapezoidal rule, Newmark dissipative schemes, HHT rule, and the Generalized-${\alpha}$ family. It was shown that, for large multi body systems, Newmark dissipative was the best election since, provided that the adequate parameters were chosen, excellent behavior was achieved in terms of efficiency and robustness with acceptable levels of accuracy. In the present paper, the performance of the described method in combination with another group of integrators, the Implicit Runge-Kutta family (IRK), is analyzed. The purpose is to clarify which kind of IRK algorithms can be more suitable for real-time applications, and to see whether they can be competitive with the already tested structural family of integrators. The final objective of the work is to provide some practical criteria for those interested in achieving real-time performance for large and complex multibody systems.

• Current Optics and Photonics
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• v.1 no.4
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• pp.402-411
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• 2017

Combined LIBS-Raman spectroscopy has been widely studied, due to its complementary capabilities as an elemental analyzer that can acquire signals of atoms, ions, and molecules. In this study, the classification of polymorphs was performed by laser-induced breakdown spectroscopy (LIBS) to overcome the limitation in molecular analysis; the results were verified by Raman spectroscopy. LIBS signals of the $CaCO_3$ polymorphs calcite and aragonite, and $CaSO_4{\cdot}2H_2O$ (gypsum) and $CaSO_4$ (anhydrite), were acquired using a Nd:YAG laser (532 nm, 6 ns). While the molecular study was performed using Raman spectroscopy, LIBS could also provide sufficient key data for classifying samples containing different molecular densities and structures, using the peculiar signal ratio of $5s{\rightarrow}4p$ for the orbital transition of two polymorphs that contain Ca. The basic principle was analyzed by electronic motion in plasma and electronic transition in atoms or ions. The key factors for the classification of polymorphs were the different electron quantities in the unit-cell volume of each sample, and the selection rule in electric-dipole transitions. The present work has extended the capabilities of LIBS in molecular analysis, as well as in atomic and ionic analysis.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.2
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• pp.96-101
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• 1996

In this paper, a simulator is designed along with S/W package for crane controllers. Due to trolley's acceleration or deceleration, cranes inherently cause swing motion of the objects in transporting heavy objects. This swing not only deteriorates the crane handling safety but also increases the processing time. To overcome these drawbacks, the fuzzy rule-based simulator is developed with inhibitory swing at final action. The computer simulation shows that the swing at initial and final positions is removed fast with small position error. The proposed simulator can be used for handling object stabley and the study of effectiveness in unmanned operation of cranes.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.12
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• pp.1100-1108
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• 2015

A camera-based real-time hand posture and gesture recognition system is proposed for controlling various devices inside automobiles. It uses an imaging system composed of a camera with a proper filter and an infrared lighting device to acquire images of hand-motion sequences. Several steps of pre-processing algorithms are applied, followed by a background normalization process before segmenting the hand from the background. The hand posture is determined by first separating the fingers from the main body of the hand and then by finding the relative position of the fingers from the center of the hand. The beginning and ending of the hand motion from the sequence of the acquired images are detected using pre-defined motion rules to start the hand gesture recognition. A set of carefully designed features is computed and extracted from the raw sequence and is fed into a decision tree-like decision rule for determining the hand gesture. Many experiments are performed to verify the system. In this paper, we show the performance results from tests on the 550 sequences of hand motion images collected from five different individuals to cover the variations among many users of the system in a real-time environment. Among them, 539 sequences are correctly recognized, showing a recognition rate of 98%.

• Korean Institute of Interior Design Journal
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• v.14 no.6 s.53
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• pp.112-119
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• 2005

Virtual reality(VR) is the technology that makes a user regard being in virtual space generated by computer as in the real world. Mainly, it has been studied about the three senses which are the sense of vision, touch and hearing in the five human senses. Through that, it is applied to the system making all the senses in the human body real. Even though the design idea of theater is brought to that of simulation theater, there are not many similarities between them and not general design rules yet. For making a better situation, in cooperation with a domestic company making a motion simulator for one or two person by itself, I have considered the minimum conditions and formations of the simulation theater being widely useful in the buildings of general commercial spaces from the environmental viewpoint, and basing on that facts I try to make some sorts of fundamental design types so that they are more available than those in the past. In this research, I have set the three types of simulation theater, the 50 seats of motion simulator for one person, the 20 seats of motion simulator and the 50 seats for two persons, in my researching range. Moreover, regarding the size of the simulation theater, I put the best specifications in order and also put them together, and then with making standards able to be reflected on the design plan, I have researched it for the purpose of the accumulation of skill in the construction of the special theater. Here, the design rule I suggested might be a design standard that it will be thought useful widely.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.3
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• pp.337-342
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• 2011

Medical lift column controlling the vertical position while supporting heavy eccentric load should have the high fatigue strength as well as the extremely low structural deflection and vibration in order to maintain the positioning accuracy. The lift column driven by a induction motor is generally in a three-step sliding boom structure and exhibits the time-varying stress distribution according to the up-and-down motion. This study is concerned with the numerical prediction of the fatigue strength of the lift column subject to the time-varying stress caused by the up-and-down motion. The stress variation during a motion cycle is obtained by finite element analysis and the fatigue life is predicted making use of Palmgren-miner's rule and S-N curves. In order to secure the numerical analysis reliability, a 3-D FEM, model in which the detailed lift column structure and the fitting parts are fully considered, is generated and the interfaces between lift column and pads are treated by the contact condition.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.13 no.2
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• pp.1-11
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• 2007

Purpose: The purpose of this study was to determine the effect of continuous wave ultrasound and pulsed wave ultrasound that influence changes in pain and range of motion when applied to patients with temporomandibular joint disability. Methods: The subjects of the study were 40 selected patients who had been diagnosed with temporomandibular joint movement restriction and had endured pain for more than two weeks. These patients had visited K orthopedic surgery in Deagu measured from October 1, 2004 to March 31, 2005. The subjects were divided into two groups with 20 patients each. The one group was applied to continuous wave ultrasound and the other group was applied to pulsed wave ultrasound at a dosage of 1.5 W/$cm^2$ for a duration of 5 minutes and eight times for two weeks. The pain perception degree were measured by using Visual Analogue Scale(VAS) and the range of motion was measured by using a rule for each group. Results: The results obtained were as follows The change in the pain perception degree were statistically significant in both group(p<0.05) ; however, the continuous wave ultrasound group showed more difference in the average decrease in the pain perception degree than did the pulsed wave ultrasound group. Both groups showed significant results regarding changed in the range of motion(p<0.05) ; Comparing the difference in the average of the range of motion between the two groups, came back from normal the range of motion of temporomandibular joint at the both groups. Conclusion : Based on the results of this study, we found that both groups showed decreased pain and increased the range of motion, but the continuous wave ultrasound method had a higher therapy effect pain and the range of motion than the pulsed wave ultrasound method to patients with temporomandibular joint disability. With such finding, we expect that according to ultrasound therapy applicant method can be helped usable accurately to patients with variety symptoms temporomandibular joint disability.

• The Journal of Korean Physical Therapy
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• v.14 no.4
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• pp.423-440
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• 2002

The purpose of this study is to investigate the conception and developmental process of stretching in sports physical therapy. This study is to find conception of stretching, feature and effect, principles and fundamental rule, consideration of enforcement and developmental process in order to use the basic material which is very helpful in the every field and the scene of sports needing stretching. Flexibility is the ability to move muscles and joints through their full ranges of motion. Flexibility is developed by stretching. About player who insufficiency of flexibility, patient and disabled person who restrict of range of motion, older adult who reduce of flexibility, promote of flexibility for upgrading stability and efficiency of body on the based of scientific principles is completed by stretching. The method of stretching has been developed with passive stretching, CR, PNF stretching, PIC stretching, MET stretching in the order. The effects that we can get through stretching are as follows : 1. Enhance physical fitness. 2. Optimize learning, practice and performance of many types of skilled movement. 3. Increase mental and physical relaxation. 4. Promote development of body awareness. 5. Reduce risk of joint sprain or muscle strain. 6. Reduce risk of back problem. 7 Reduce muscular soreness. 8. Reduce the severity of painful menstruation for female athletes. 9. Reduce muscular tension. 10. Advance recognition of body.

• Steel and Composite Structures
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• v.36 no.6
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• pp.689-702
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• 2020

The current study deals with the size-dependent free vibration analysis of graphene nanoplatelets (GNPs) reinforced polymer nanocomposite plates resting on Pasternak elastic foundation containing different boundary conditions. Based on a four variable refined shear deformation plate theory, which considers shear deformation effect, in conjunction with the Eringen nonlocal elasticity theory, which contains size-dependency inside nanostructures, the equations of motion are established through Hamilton's principle. Moreover, the effective material properties are estimated via the Halpin-Tsai model as well as the rule of mixture. Galerkin's mathematical formulation is utilized to solve the equations of motion for the vibrational problem with different boundary conditions. Parametrical examples demonstrate the influences of nonlocal parameter, total number of layers, weight fraction and geometry of GNPs, elastic foundation parameter, and boundary conditions on the frequency characteristic of the GNPs reinforced nanoplates in detail.

• Journal of the Korean Society of Costume
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• v.58 no.9
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• pp.166-175
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• 2008

For the structural firefighting protective clothing, it can show a synergy effect when it satisfies smart fabric to block off a harmful environmental element and ergonomics design that apply range of motion of human body and appropriate size system. There are various standards about the structural firefighting protective clothing, but it's difficult to find a rule about movement suitability because the performance of the material holds a lot of the rules. Therefore, the purpose of this study is to propose a scheme to evaluate the current structural firefighting protective clothing and to improve movement suitability by research on the actual condition. For this, the survey about wearer acceptability scale on design and size and about improvement requirements was executed gathering firefighters' opinion. Questionnaire was composed with 23 items about satisfaction on current structural firefighting protective clothing, body suitability, movement suitability, improvement requirement and subjective information. As a results, Korean firefighters demand ergonomics design of structural firefighting protective clothing which to minimize restriction of body movement and to maximize body suitability.