• 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 the Korean Society of Physical Medicine
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• v.17 no.1
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• pp.49-61
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• 2022

PURPOSE: This study compared the effects of proprioceptive sensation, subacromial space, and dynamic function according to proprioceptive neuromuscular facilitation (PNF), static stretching (SS), and complex rotational stretching (CRS). METHODS: Thirty students without any musculoskeletal disease who volunteered to participate were included in this study. The following metrics were measured to evaluate the function and stability under the normal conditions, with the PNF, SS, and CRS: special test and flexion, extension, abduction, adduction, internal rotation, external rotation (shoulder range of motion) and reaching distance on the medial (ME), superolateral (SL), inferolateral (IL), and subacromial space and proprioceptive sensation were evaluated. All measures were analyzed using one-way ANOVA and repeated measures of ANOVA. RESULTS: A clear difference in adduction in the range of motion was observed in all groups (p < .05). Significant differences could not be identified in all values in the error test, except for Ab (p < .05). Significant differences in reach were noted in all directions of the SS and PNF in the Me, SL, and IL (p < .05). After the intervention, significant differences in the average values could be identified in all groups except for the SS group after rest (p < .05). After the intervention, there was a significant difference between the CRS and SS and PNF groups (p < .05). CONCLUSION: The application of CRS is as helpful as the existing SS and PNF for improving the joint range of motion improvement, shoulder balance, and subacromial space.

• The Journal of Korean Physical Therapy
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• v.29 no.4
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• pp.223-226
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• 2017

Purpose: This study examined two trunk strategies - medio-lateral ramp and anterior-posterior ram - and their effects on pelvis and trunk movements, providing basic material for safe ramp utilization. Methods: The present study included 20 asymptomatic males recruited from a local university. Participants were asked to stand with their feet shoulder-width apart. Their dorsal side faced the camera, and measurements were performed while standing in a neutral double stance, one leg stance, $15^{\circ}$ of medial and lateral ramp, and $15^{\circ}$ of anterior and posterior ramp. Participants were allowed to practice for 3 minutes, and each participant had a 30 seconds rest between the two ramp conditions. One-way repeated measures analysis of variance was used to determine the effects the ramp conditions on spinal alignment. In all analyses, p<0.05 was used to indicate statistical significance. Results: The trunk-inclination angle on the posterior ramp was significantly lower than that of the double stance position (p<0.05). The trunk imbalance angle was significantly higher on the medial ramp, than that on the double stance position (p<0.05). The pelvic position and pelvic torsion angles were significantly higher in the medial, lateral, and anterior ramp positions than that of the double stance position (p<0.05). The pelvic rotation angles on the medial, lateral, and anterior ramps were significantly lower than that of the double stance position (p<0.05). Conclusion: These findings suggest that when people are exposed to the same form of ramp for an extended period, posture modifications may be triggered.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.53-56
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• 2001

In this paper we discuss a direct satellite broadcasting system for vehicle. The proposed satellite-steering algorithm and controller based on it are designed for a communication and broadcasting system which uses the Mugungwha satellite. The Mugungwha satellite that the proposed system should steer is a geostationary orbit device. The satellite-steering algorithm computes azimuth and elevation with reference to a stationary point on earth. This is extended to a real satellite steering algorithm that considers position and attitude. Real moving position and attitude are represented by latitude, longitude, roll, pitch and yaw. To apply these five pieces of information to the reference satellite steering algorithm, we introduce Euler's degree coordinates that express independently the rotation of each axis relative to an axis. There are two ways a basic algorithm of the antenna of a vehicle can track and orient to satellite. One way is a feedback loop method for broadcasting gain, while the other is a feedback loop method for position and attitude of a vehicle. In the present paper, we design a controller of satellite broadcasting system for a vehicle using an algorithm that combines the two methods. We performed a simulation and experiment to prove effectiveness.

• Journal of the Korean Institute of Intelligent Systems
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• v.8 no.2
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• pp.50-59
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• 1998

This paper presents stabilization and adaptive control of flexible single link robot manipulator system by self-recurrent neural networks that is one of the neural networks and is effective in nonlinear control. The architecture of neural networks is a modified model of self-recurrent structure which has a hidden layer. The self-recurrent neural networks can be used to approximate any continuous function to any desired degree of accuracy and the weights are updated by feedback-error learning algorithm. When a flexible manipulator is rotated by a motor through the fixed end, transverse vibration may occur. The motor toroque should be controlled in such a way that the motor rotates by a specified angle, while simultaneously stabilizing vibration of the flexible manipuators so that it is arresed as soon as possible at the end of rotation. Accurate vibration control of lightweight manipulator during the large changes in configuration common to robotic tasks requires dynamic models that describe both the rigid body motions, as well as the flexural vibrations. Therefore, a dynamic models for a flexible single link robot manipulator is derived, and then a comparative analysis was made with linear controller through an simulation and experiment. The results are proesented to illustrate thd advantages and imporved performance of the proposed adaptive control ove the conventional linear controller.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.21 no.4
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• pp.466-474
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• 2014

Purpose: The purpose of this study was to identify the relationship between emotional intelligence and stress coping of nurses in hospitals. Method: The study was a descriptive-correlational study with a convenience sample of 298 nurses. Descriptive statistics t-test, Mann-Whitney U, One-way ANOVA and Pearson correlation coefficients were used for data analysis. Results: The results of this study were as follows; Emotional intelligence was higher in married nurses than unmarried nurses (t=-2.90, p=.004). Nurses with a clinical career of 4~7 years had better stress coping than nurses with shorter careers (F=5.60, p=.004). Ward nurses better stress coping than nurses in emergency rooms and Intensive care units (F=4.43, p=.013). Fixed shift nurses had better stress coping than nurses on rotation shifts (t=-2.37, p=.019). There was a significant positive correlation between emotional intelligence and stress coping(r=.29, p<.001). Conclusion: The results indicate that stress coping is better in nurses with higher emotional intelligence, 4~7 year clinical experience, working on ward a as well as having a fixed shift. However further development and application of programs which can improve nurses' emotional intelligence are needed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.6
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• pp.989-1005
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• 2010

Cooperative diversity is a technique with which a virtual multiple antenna array is established among the single antenna users of the wireless network to realize space diversity. Signal space diversity (SSD) is a bandwidth-efficient diversity technique, which uses constellation rotation and interleaving techniques to achieve diversity gain. A new cooperative diversity scheme with rotated constellations (RCCD) is proposed in this paper. In this scheme, data are modulated by using a rotated constellation, and the source and the relays transmit different components of the modulated symbols. Since any one of the components contains full information of the symbols, the destination can obtain multiple signals conveying the same information from different users. In this way, space diversity is achieved. The RCCD scheme inherits the advantage of SSD - being bandwidth-efficient but without the delay problem of SSD brought by interleaving. The symbol error rate of the RCCD scheme is analyzed and simulated. The analysis and simulation results show that the RCCD scheme can achieve full diversity order of two when the inter-user channel is good enough, and, with the same bandwidth efficiency, has a better performance than amplify-and-forward and detect-and-forward methods.

• Korean Journal of Applied Biomechanics
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• v.15 no.4
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• pp.97-104
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• 2005

Previous studies of kinematic analysis of golf swing usually dealt with variations vertically. The purpose of the study was to examine the horizontal hip joints motion of the fifteen male professional golfers during driver swinging. Kinematic variables were calculated by the Kwon3D motion analysis program. Paired t-tests and one-way ANOVA were used to compare the hip height, distance, displacement, and position differences. Results showed that there were no hip height changes and no hip height differences between left and right hip from address to impact. The axis of the backswing was braced right hip, the axis of the downswing was moving left hip. Hips position at the top of the backswing showed that hips move to target prior to hands, which means the sequential motion of the chain linked body segments. From address to impact, left hip moving distance was longer than right hip(p<.001), but during the whole swing, right hip moving distance was longer than left hip(p<.001). Hip rotation angle to target line was $-48.14{\pm}9.32^{\circ}$ at top of the backswing, $40.88{\pm}8.44^{\circ}$ at impact, and $104.70{\pm}8.14^{\circ}$ at finish.

• ETRI Journal
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• v.38 no.6
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• pp.1145-1152
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• 2016

Because the nodes in a wireless sensor network (WSN) are mobile and the network is highly dynamic, monitoring every node at all times is impractical. As a result, an intruder can attack the network easily, thus impairing the system. Hence, detecting anomalies in the network is very essential for handling efficient and safe communication. To overcome these issues, in this paper, we propose a rule-based anomaly detection technique using roaming honeypots. Initially, the honeypots are deployed in such a way that all nodes in the network are covered by at least one honeypot. Honeypots check every new connection by letting the centralized administrator collect the information regarding the new connection by slowing down the communication with the new node. Certain predefined rules are applied on the new node to make a decision regarding the anomality of the node. When the timer value of each honeypot expires, other sensor nodes are appointed as honeypots. Owing to this honeypot rotation, the intruder will not be able to track a honeypot to impair the network. Simulation results show that this technique can efficiently handle the anomaly detection in a WSN.

• The Transactions of the Korea Information Processing Society
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• v.1 no.1
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• pp.73-80
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• 1994

Fourier Descriptors(FD) is a common way for representing the boundary of an object. In this paper, an algorithm has been implemented to do object recognition by using FD. This is applied to various tool object, and is tested. This implementation contains two parts: image acquisition and object recognition. Appropriate lighting, viewing angle, and strong contrast of background and object are taken into account in this aspect. Minimum distances are calculated by using FD's and boundary matching among objects on the process of object recognition. Rotation, translation and scaling of the object will not influence the performance of the algorithm. Experiments show that we can use only one fourth of 1024 FD coefficients to do raped object recognition.