• The Korean Journal of Emergency Medical Services
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• v.14 no.1
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• pp.5-18
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• 2010

Objective : This study compares Video laryngoscope and Direct laryngoscope in tracheal Intubation on rapidity and accuracy by paramedic and aims to improve efficiency of airway management and survival rate in pre-hospital treatment for the patients with severe trauma, cardiac arrest or dyspnea caused by acute diseases. Methods : 60 paramedics were recruited from 13 fire stations located in C province. With the consent of the paramedics, likelihood ratio test was carried out and they were divided into two different groups; DL group (30) and GVL group (30). Regarding intubation conditions, difficult airway grade I, grade II and grade III as well as sniffing position and neutral position were examined. This study also compared between ambulance in motion and in stand still. Frequency, average and standard deviation were analyzed with statistics program, SPSS WIN 17.0 and repeated measure design was introduced to examine inter-relations between position, grade and groups. Results : Intubation was performed more rapidly in neutral position and GVL than in sniffing position and DL(F = 15.260, p = .000). Rapidity value was better with grade I and grade II than grade III and better with GVL than DL(F = 32.629, p = .000). Accuracy value was higher with neutral position and GVL than sniffing position and DL(F = 5.008, p = .011). grade III was less accurate than grade I, grade II and GVL was more accurate than DL(F = 10.966, p = .000). Ambulance motion status did not show any statistically significant differences in accuracy and rapidity. Conclusion : Given this study results, neutral position is better for the patient with severe trauma. For a better survival, GVL intubation can be considered since GVL can enhance accuracy as well as rapidity regarding difficult airway. Since there is no significant differences in ambulance motion factors, intubation can be recommended even in moving ambulance for shortening traveling time to a hospital.

• Restorative Dentistry and Endodontics
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• v.41 no.4
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• pp.304-309
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• 2016

Objectives: The purpose of this study was to compare the maximum screw-in forces generated during the movement of various Nickel-Titanium (NiTi) file systems. Materials and Methods: Forty simulated canals in resin blocks were randomly divided into 4 groups for the following instruments: Mtwo size 25/0.07 (MTW, VDW GmbH), Reciproc R25 (RPR, VDW GmbH), ProTaper Universal F2 (PTU, Dentsply Maillefer), and ProTaper Next X2 (PTN, Dentsply Maillefer, n = 10). All the artificial canals were prepared to obtain a standardized lumen by using ProTaper Universal F1. Screw-in forces were measured using a custom-made experimental device (AEndoS-k, DMJ system) during instrumentation with each NiTi file system using the designated movement. The rotation speed was set at 350 rpm with an automatic 4 mm pecking motion at a speed of 1 mm/sec. The pecking depth was increased by 1 mm for each pecking motion until the file reach the working length. Forces were recorded during file movement, and the maximum force was extracted from the data. Maximum screw-in forces were analyzed by one-way ANOVA and Tukey's post hoc comparison at a significance level of 95%. Results: Reciproc and ProTaper Universal files generated the highest maximum screw-in forces among all the instruments while M-two and ProTaper Next showed the lowest (p < 0.05). Conclusions: Geometrical differences rather than shaping motion and alloys may affect the screw-in force during canal instrumentation. To reduce screw-in forces, the use of NiTi files with smaller cross-sectional area for higher flexibility is recommended.

• Journal of Ocean Engineering and Technology
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• v.26 no.6
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• pp.7-13
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• 2012

This paper presents a numerical study of the wave loads acting on offshore structures using a Cartesian-grid-based flow simulation method. Finite volume discretization with a volume-of-fluid (VOF) method is adopted to solve two-phase Navier-Stokes equations. Among the many variations of the VOF method, the CICSAM scheme is applied. The body boundary conditions are satisfied using a porosity function, and wave generation is carried out by using transient (wave or damping) zone approaches. In order to validate the present numerical method, three different basic offshore structures, including a sphere, Pinkster barge, and Wigley model, are numerically investigated. First, diffraction and radiation problems are solved using the present numerical method. The wave exciting and drift forces from the diffraction problems are compared with potential-based solutions. The added mass and wave damping forces from the radiation problems are also compared with the potential results. Next, the wave-induced motion responses of the structures are calculated and compared with the existing experimental data. The comparison results are fairly good, showing the validity of the present numerical method.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.4
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• pp.224-231
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• 2013

The concept of the natural frequency is useful for understanding the characters of oscillating systems. However, when a circular cylinder floating horizontally on the water surface is heaving, due to the hydrodynamic forces, the system is not governed by the equation like that of the harmonic one. In this paper, in order to shed some lights on the more correct use of the concept of the natural frequency, a problem of the heaving circular cylinder is analyzed in the time domain. The equation of motion, an integro-differential equation, was derived following the fashion of Cummins (1962), and its coefficients including the retardation function were obtained using the numerical solution of Lee (2012). The equation was solved numerically, and the experiment was also carried out in the CNU flume. Using our numerical and experimental results, the natural frequency was defined as its average value given by the motion data excluding those of the initial stage. Our results were then compared with those of the existing investigations such as Maskell and Ursell (1970), Ito (1977) and Yeung (1982) as well as the newly obtained results of Lee (2012). Comparison showed that the natural frequency obtained here agrees well with that of Lee (2012), which was found through the frequency domain analysis. It was also shown that the approximation of heaving motion by a damped harmonic oscillation, which was regarded as suitable by most previous investigators, is not physically suitable for the reason that can be clearly shown through comparing the shape of MCFRs(Modulus of Complex Frequency Response). Furthermore, we found that although the previous approximations yield the damping ratio significantly different from our result the magnitude of natural frequency is not much different from our result.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.2
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• pp.2071-2076
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• 2020

Background: Based on the understanding of the muscle activation relationship between the infraspinatus and posterior deltoid muscles to according to the angle of motion during external rotation on glenohumeral joint, effective shoulder joint strengthening exercise for the prevention and rehabilitation of shoulder injury due to muscle strength imbalance can be performed by achieving the ideal muscle activity ratio during exercise. Objectives: To compare and analyze the muscle activation changes and activity ratio of the infraspinatus and posterior deltoid muscles according to the glenohumeral external rotation angle. Design: Quasi-randomized trial. Methods: The study included 48 healthy male and female adults who provided informed consent for participation in the study. All the subjects performed isometric glenohumeral external rotation by setting the angle of motion to 30°, 45°, and 60° using a 5 kg resistance weight pulley. On surface electromyography, the differences in muscle activation and activity ratio between the infraspinatus and posterior deltoid muscles were investigated. Results: A significant difference in muscle activation was found in the comparison between the infraspinatus and posterior deltoid muscles according to the glenohumeral external rotation angle (P<.05). The muscle activation levels of the infraspinatus and posterior deltoid muscles were highest at the external rotation angles of 30° and 60°, respectively. The muscle activity ratio between the infraspinatus and posterior deltoid muscles also showed a significant difference (P<.05) and was highest at the shoulder external rotation angle of 30°. Conclusion: The findings of this study suggest that muscle activity is the highest at the shoulder external rotation angle of 30° in healthy individuals.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.2
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• pp.2042-2051
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• 2020

Background: Many trials have been conducted the methods and types of intervention of form rollers, but no research has been done yet that mixes the methods and types of intervention. Objectives: To analyze the effects of myofascial release on the improvement of range of motion (ROM), flexibility, pain pressure threshold, and balance. Design: Randomized controlled trial. Methods: All subjects measured ROM, flexibility, pressure pain threshold, and dynamic balance by pre-test. After pre-test, subjects were randomized that static-vibration foam rolling group (n=12), dynamic-vibration foam rolling group (n=12), general foam rolling group (n=12). For the intervention, 3 sets of 90 seconds were applied to each group, and rest time was set to 60 seconds between sets. In the post-test and follow-up test after 10 minutes, all three groups were measured the ROM, flexibility, pressure pain threshold, and dynamic balance. Results: The results of comparing ROM, flexibility, pressure pain thresholds, dynamic balance ability appeared higher significant difference in the pre-post-10 minutes follow up test in comparison between time in the intragroup (P<.001). As a result of comparing the change of pre-post-10 minutes follow up, static vibration foam rolling showed higher significant difference compared to control groups (P<.001). Conclusion: Through this study, when foam rolling is applied within the same intervention time, static foam rolling can be expected to have a better effect than the existing dynamic foam rolling as well as vibration foam roller can expect better effect than general foam rolling.

• Physical Therapy Rehabilitation Science
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• v.9 no.1
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• pp.1-9
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• 2020

Objective: This study aimed to investigate the immediate effects of intervention using neuromuscular control, self-stretching (SS), and neck stabilization exercises (NSEs) on neck pain, range of motion (ROM), and proprioception of position sense in adults with neck discomfort. Design: Three-group pretest-posttest design. Methods: Forty-four adults who complained of neck pain participated in the experiment. They were randomly assigned to the following groups: neuromuscular control exercise (NMCE) group (n=15), SS group (n=14) and NSE group (n=15). The NMCE group did rolling with only upper limb pattern on both sides. The SS group performed neck stretching on each side, 3 sets of 30 seconds for each muscle. The NSE group had the pressure biofeedback applied with increases in pressure by 2 mmHg at a time from 20-30 mmHg while in the hook-lying position. All groups performed exercises for 10 minutes. Neck pain, ROM, and proprioception were measured to determine differences between the intervention methods. Results: Intra-group comparisons showed significant improvement after exercise in pain, ROM, and proprioception in the NMC group (p<0.05). In the comparison between groups, the NMC group had a significant decrease in pain compared to the other two groups (p<0.05). There was no difference in ROM between the groups but the NMC group showed significant improvement in left rotation compared to the stabilization exercise group (p<0.05). For proprioception, the NMC group had significantly lower error than the other two groups (p<0.05). Conclusions: NMCEs through upper extremity pattern rolling exercise is effective in improving neck pain, ROM, and proprioception.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.4
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• pp.112-118
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• 2013

The selection of appropriate ground motions and reasonable modification are becoming increasingly critical in reliable prediction on seismic performance of structures. A widely used amplitude scaling approach is not sufficient for robust structural evaluation considering a site specific seismic hazard because only one spectral value is matched to the design spectrum typically at the structural fundamental period. Hence alternative approaches for ground motion selection and modifications have been suggested. However, there is no means to evaluate such methodologies yet. In this study, it is focused to describe the main questions resided in the amplitude scaling approach and to propose a regression model for structural damage as point of comparison. Spectrum compatible approach whose resulting spectrum matches the design spectrum at the entire range of the structural period is considered as alternative to be compared to the amplitude scaling approach. The design spectrum is generated according to ASCE7-05.

• Restorative Dentistry and Endodontics
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• v.42 no.3
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• pp.224-231
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• 2017

Objectives: To determine the actual revolutions per minute (rpm) values and compare the cyclic fatigue life of Reciproc (RPC, VDW GmbH), WaveOne (WO, Dentsply Maillefer), and TF Adaptive (TFA, Axis/SybronEndo) nickel-titanium (NiTi) file systems using high-speed camera. Materials and Methods: Twenty RPC R25 (25/0.08), 20 WO Primary (25/0.08), and 20 TFA ML 1 (25/0.08) files were employed in the present study. The cyclic fatigue tests were performed using a dynamic cyclic fatigue testing device, which has an artificial stainless steel canal with a $60^{\circ}$ angle of curvature and a 5-mm radius of curvature. The files were divided into 3 groups (group 1, RPC R25 [RPC]; group 2, WO Primary [WO]; group 3, TF Adaptive ML 1 [TFA]). All the instruments were rotated until fracture during the cyclic fatigue test and slow-motion videos were captured using high-speed camera. The number of cycles to failure (NCF) was calculated. The data were analyzed statistically using one-way analysis of variance (ANOVA, p < 0.05). Results: The slow-motion videos were indicated that rpm values of the RPC, WO, and TFA groups were 180, 210, and 425, respectively. RPC ($3,464.45{\pm}487.58$) and WO ($3,257.63{\pm}556.39$) groups had significantly longer cyclic fatigue life compared with TFA ($1,634.46{\pm}300.03$) group (p < 0.05). There was no significant difference in the mean length of the fractured fragments. Conclusions: Within the limitation of the present study, RPC and WO NiTi files showed significantly longer cyclic fatigue life than TFA NiTi file.

• Korean Journal of Applied Biomechanics
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• v.13 no.2
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• pp.65-74
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• 2003

The purpose of this study was to analyze kinematic variables in the badminton smash motion through 3-dimensional image analysis. The kinematic variables were velocity of joints in upper limbs, the angle of wrist in the impact, and the angular velocity of the top of racket head. The smash motions of four male badminton players in H University and four male students at department of the physical education in K University who were not majoring in badminton were analyzed kinematically and the attained conclusions were as follow. 1. The velocity of segments in upper limbs of the unskilled group was faster than that of the skilled group. The movement pattern was fast back swing-slow impact moment-fast fellow through in the unskilled group, but slow back swing-fast impact moment-slow follow through in the sullied group. 2. As the BS phases, the velocity of segment in right shoulder was different significantly between groups. Right elbow and right wrist segments, velocity of racket head was different significantly between groups(p<.05) by IP phases. As the FT phases, there was no significant difference. 3. The angle of right wrist at the impact, the angle of palm flexion and the angle of palm flexion in aspect were shown that the skilled group was higher than unskilled group. There was no significant difference. 4. The velocity of racket head was shown that the unskilled group has fast velocity, but the angle velocity was shown the unskilled group has slow. 5. The angle velocity of racket head in aspect were no significant difference between groups, but maximal angle velocity was different significantly between groups(p<.05).