• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.21 no.2
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• pp.33-37
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• 2015

Background: The purpose of this study on the effects of deep cervical flexors strengthening exercise to forward head posture and pain of neck in patients with chronic neck pain. Method: We selected 30 subjects among neck pain patients and carried out measurements. The subjects' forward head posture was measured including head tilt angle (HTA), neck flexion angle (NFA) and forward shoulder angle (FSA), neck disability index (NDI), numeric rating scale (NRS). The subjects underwent deep cervical flexors muscle strengthening with pressure bio-feedback device for 4 weeks. Then, after intervention, the subjects' forward head posture was measured again. It was performed Wilcoxon signed-ranks test for confirming the effect of deep cervical flexor muscles strengthening exercise. Results: As a result of comparison of measurements before and after intervention, we found that there were statistically significant improvement in the subjects' NDI, NRS and forward head posture including head tilt angle, neck flexion angle and forward shoulder angle. Conclusion: We concluded that deep cervical flexors strengthening exercise has the effect of alleviation of neck pain patients and is effective for forward head posture.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.1
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• pp.6-11
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• 2005

In this paper, two types of vertical SIT(Static Induction Transistor) structures are proposed to improve their electrical characteristics including the blocking voltage. Besides, the two dimensional numerical simulations were carried out using ISE-TCAD to verify the validity of the device and examine the electrical characteristics. First, a trench gate region oxide power SIT device is proposed to improve forward blocking characteristics. Second, a trench gate-source region power SIT device is proposed to obtain more higher forward blocking voltage and forward blocking characteristics at the same size. The two proposed devices have superior electrical characteristics when compared to conventional device. In the proposed trench gate oxide power SIT, the forward blocking voltage is considerably improved by using the vertical trench oxide and the forward blocking voltage is 1.5 times better than that of the conventional vertical power SIT. In the proposed trench gate-source oxide power SIT, it has considerable improvement in forward blocking characteristics which shows 1500V forward blocking voltage at -10V of the gate voltage. Consequently, the proposed trench oxide power SIT has the superior stability and electrical characteristics than the conventional power SIT.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.196-197
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• 2006

In this paper, two types of vertical SIT(Static Induction Transistor) structures are proposed to improve their electrical characteristics including the blocking voltage. Besides, the two dimensional numerical simulations were carried out using ISE-TCAD to verify the validity of the device and examine the electrical characteristics. First, a trench gate region oxide power SIT device is proposed to improve forward blocking characteristics. Second, a trench gate-source region power SIT device is proposed to obtain more higher forward blocking voltage and forward blocking characteristics at the same size. The two proposed devices have superior electrical characteristics when compared to conventional device. In the proposed trench gate oxide power SIT, the forward blocking voltage is considerably improved by using the vertical trench oxide and the forward blocking voltage is 1.5 times better than that of the conventional vertical power SIT. In the proposed trench gate-source oxide power SIT, it has considerable improvement in forward blocking characteristics which shows 1500V forward blocking voltage at -10V of the gate voltage. Consequently, the proposed trench oxide power SIT has the superior stability and electrical characteristics than the conventional power SIT.

• The Journal of Korean Physical Therapy
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• v.31 no.1
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• pp.1-6
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• 2019

Purpose: This paper proposes proper and effective neck exercises by comparing the deep and superficial cervical flexor muscle activities and thickness according to the pressure level during cranio-cervical flexion exercises between a normal posture group and forward head posture group. Methods: A total of 20 subjects (8 males and 12 females) without neck pain and disabilities were selected. The subjects' craniovertebral angles were measured; they were divided into a normal posture and a forward head posture group. During cranio-cervical flexion exercises, the thickness of the deep cervical flexor neck muscle and the activity of the surface neck muscles were measured using ultrasound and EMG. Results: The results showed that the thickening of the deep cervical flexor was increased significantly to 28 and 30 mmHg in the forward head posture group. The sternocleidomastoid muscle activity increased significantly to 24, 26, 28, and 30 mmHg in the forward head posture group. The anterior scalene muscle activity increased significantly to 26, 28, and 30mmHg in the forward head posture group. A significant difference of 26, 28, and 30 mmHg in the sternocleidomastoid and anterior scalene muscles was observed between two groups. Conclusion: To prevent a forward head posture and maintain proper cervical curve alignment, the use of the superficial cervical flexor muscles must be minimized. In addition, to perform a cranio-cervical flexion exercises to effectively activate the deep cervical flexor muscles, 28 and 30 mmHg for normal posture adults and 28 mmHg for adults with forward head postures are recommended.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.5
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• pp.43-52
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• 2001

Y. Zheng introduced a new type of cryptograghic primitive as \"signcryption\", which combines a function of digital signature scheme with a symmetric key encryption algorithm. Signcryption doesn\`t only provide authenticity and confidentiality in a single step, but also give more efficient computation than the traditional \"signature-then-encryption\". And C. Gamage proposed a proxy-signcryption that efficiently combines a proxy signature with the signcryption. But, in the proposed signcryption schemes, one who obtains the sender\`s private key can recover the original message of a signcrypted text. That is, forward secrecy is not offered by the signcryption scheme with respect to the sender\`s private key. In this paper, we will propose a modified signcryption of Zheng\`s signcryption and a variant of proxy-signcryption with forward secrecy.ith forward secrecy.

• PNF and Movement
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• v.19 no.2
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• pp.163-172
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• 2021

Purpose: This study investigated the correlation between physical function and forward head posture in spastic diplegia. Methods: The subjects of this study were 10 spastic diplegia patients. We took pictures of the subjects' craniovertebral angle with a digital camera to determine the degree of forward head posture and then analyzed them using the NIH image J program. The physical function test used the TCMS, the BBT, and a spirometer. The data in this study were measured using SPSS version 23.0, and the statistical significance level α was 0.05. A Pearson correlation coefficient analysis was performed to identify the correlation between the degree of the subject's head forward position and physical function. Results: When we performed the BBT and spirometer tests, the subjects' forward head postures were not correlated (p < 0.05). However, with the TCMS, there was a strong correlation between the forward position of the head and balance, with balance decreasing as the head position increased (p < 0.05). Conclusion: Spastic diplegia patients with severe forward head posture showed problems with static balance, dynamic balance, and equilibrium reaction when sitting. Intervention on the right posture and preventive activities will be needed to improve the health of spastic diplegia patients and prevent future problems with physical function.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.5
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• pp.367-375
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• 2022

Generally, a proportional-resonant controller is used to eliminate steady-state errors during the voltage-current control of a double-conversion uninterruptible power supply (UPS) in a stationary reference frame. Additionally, the feed-forward control compensating for the load current, which can be considered a disturbance of the voltage controller, can be used to improve the disturbance rejection performance. However, during the parallel operation of UPSs, circulating current can occur between UPS modules when performing both feed-forward control and droop control because feed-forward control reduces the circulating current impedance. This study proposes a feed-forward compensation technique that considers the impedance of circulating current. An additional feed-forward compensation technique is developed to enhance the disturbance rejection performance. The validity of the proposed feed-forward compensation technique is verified by the experiment results of the parallel operation of a 500 W double-conversion UPS module.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.3
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• pp.161-164
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• 2000

A simple methode for calculating the forward voltage drop of IGBTs is presented, on the voltage drops on the p+ body, the reverse biased depletion region between p+body and epi-layer, the epi layer, and the forward biased collector junction. The decrease of the total current density in the epi layer near the p+ body is taken into account. The proposed methode allows a simple but accurate determination of the forward voltage drop in IGBTs, avoiding the complex path taken in the previous model for the forward voltage drops on channel, accumulation region, and epi region. Numerical simulations for 1kV NPT-IGBT with a uniformly doped collector are shown to support the analytical results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.5
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• pp.426-435
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• 2013

The diversity-multiplexing tradeoff (DMT) functions of three special half-duplex (HD) dynamic decode-and-forward (DDF) protocols with multiple antennas only at the source node, only at the destination node, and only at the relay node are analytically derived. The DMT functions of these three relay protocols are compared with one another and with those of the nonorthogonal amplify and forward (NAF) protocols.

• Transactions of Materials Processing
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• v.11 no.1
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• pp.84-89
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• 2002

This study is concerned with the analysis of the forming characteristics of radial-forward extrusion. Angle between radial and forward extrusion, gap height, and friction factor are considered as important design factors to affect forming characteristics in radial-forward extrusion. The rigid-plastic finite element method is adopted to analyze the effects of design factors on forming loads. The incremental rates of loads are nearly constant except the deformation zone from radial to forward extrusion. The smaller angle induces lesser force increment, therefore forming load increases as the angle increases. Maximum load also increases as gap-height decreases and friction factor increases.