• Physical Therapy Korea
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• v.2 no.1
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• pp.71-79
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• 1995

The purpose of this paper is to review the literature of AIDS/HIV (acquired immune deficiency syndrome/human immunodeficiency virus) and to introduce physical therapy of the AIDS client. It was first reported that five young homosexual men, in 1981 in Los Angeles, died of pneumonia caused by pneumocystis carinii - called "pest of twentieth century". AIDS was implied a fatal breakdown of the functioning of the normal human immune system. The major routes of transmission has occurred via l)sexual contact between men, 2)heterosexual intercourse, 3)contaminated blood and blood products, and 4)intrauterine or pre-natal infection from mothers. AIDS clients who may require physical therapy for a wide range of problems due to respiratory, neurological, musculoskeletal and painful syndromes as well as general decline in fitness and function. AIDS is growing rapidly in our contury as well as all over the world. Therefore, physical therapist has to correct his understandings of AIDS in order to protect himself and to give proper physical therapy to the AIDS clients.

• Journal of Communications and Networks
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• v.3 no.4
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• pp.342-350
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• 2001

The Internet routing instability, or the rapid fluctuation of network reachability information, is an important problem currently facing the Internet engineering community. High levels of network instability can lead to packet loss, increased network latency, and delayed routing convergence. At the extreme, high levels of routing instability can lead to the loss of internal connectivity in wide-area networks. In this paper, we investigate the variation of domain degree and domain count of the inter-domain network over time by using linear regression model in order to analyze the topology variation of inter-domain network. We Also propose an efficient policy management model to reduce the instability in the inter-domain routing system. The proposed model can be used to identify whether a routing policy is adequate to reduce convergence time that is required to return to a normal state when BGP routing instability happens. Experimental analysis shows that the proposed model can be used to set up routing policy in domains for the purpose of minimizing the effects and the propagation of BGP routing instability.

• Journal of Communications and Networks
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• v.12 no.6
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• pp.592-599
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• 2010

In recent years, significant improvements have been made to the techniques used for analyzing satellite communication and attacking satellite systems. In 2003, a research team at Los Alamos National Laboratory, USA, demonstrated the ease with which civilian global positioning system (GPS) spoofing attacks can be implemented. They fed fake signals to the GPS receiver so that it operates as though it were located at a position different from its actual location. Moreover, Galileo in-orbit validation element A and Compass-M1 civilian codes in all available frequency bands were decoded in 2007 and 2009. These events indicate that cryptography should be used in addition to the coding technique for secure and authenticated satellite communication. In this study, we address this issue by using an authenticated key-exchange protocol to build a secure and authenticated communication channel for satellite communication. Our protocol uses identity-based cryptography. We also prove the security of our protocol in the extended Canetti-Krawczyk model, which is the strongest security model for authenticated key-exchange protocols, under the random oracle assumption and computational Diffie-Hellman assumption. In addition, our protocol helps achieve high efficiency in both communication and computation and thus improve security in satellite communication.

• Journal of IKEEE
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• v.2 no.2 s.3
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• pp.173-177
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• 1998

Under indoor environment, in case that wireless optical LAN does not obtain the line-of-sight between transmitter and receiver, hemi-spherical lens or reflector must be adopted to get broader beam width. The beam tilt and the fluctuations in amplitude and phase of optical signal through indoor-space occur due to the turbulene. This fading often results in unacceptably large bit error probabilities and thus performance degradation of wireless optical communications. In this paper, when the spherical filter at the front-end of transmitter and receiver is used for wireless optical channel not satisfying line-of-sight, the signal-to-noise ratio as to zenithal angle and the effect from the turbulence due to indoor temperature are investigated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.11
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• pp.873-880
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• 2020

In this paper, we propose a guidance filter to estimate line of sight rate with strapdown seeker measurements and INS(Inertial Navigation System) information. The measurements of proposed guidance filter consisted of the LOS(Line of Sight) and relative position that can be calculated with the seeker's measurements, INS information and known target position, also the filter is based on an asynchronous filter to use outputs of the two sensors that are out of synchronous and period. Through the proposed filter, we can reduce the effect on parasitic loop that can be caused by using large time delay seeker and improve the estimation performance.

• Smart Media Journal
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• v.4 no.4
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• pp.64-69
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• 2015

In this paper, we have proposed a tapered slot antenna for UWB communication system. The tapered slot antenna has directional radiation and broad bandwidth. Proposed tapered slot antenna is designed using Ansys Inc. HFSS and its VSWR, return los, and radiation pattern is analyzed. Operating band of the antenna were satisfied -10 dB S11 and $VSWR{\leq}2$ in 2.7 ~ 4.8 GHz band. The radiation pattern of the antenna is showed in E-plane (YZ plane) and the H-plane (XZ plane) and the highest gain of 7.3 dBi is seen at 4.5 GHz. Therefore, proposed tapered slot antenna has wide bandwidth characteristic and directional for location awareness.

• Clinics in Shoulder and Elbow
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• v.19 no.2
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• pp.84-89
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• 2016

Background: The purpose of this study was to assess the results of arthroscopic bridging repair using a human dermis allograft in the treatment of massive irreparable rotator cuff tears. Methods: From November 2009 to April 2011, 12 patients underwent arthroscopic bridging repair using a human dermis allograft in the treatment of massive irreparable rotator cuff tears. Patients were followed for an average of 33.9 months. Clinical outcome was evaluated preoperatively and postoperatively using the mean University of California, Los Angeles (UCLA) score and the Korean Shoulder Scoring System (KSS). Magnetic resonance imaging (MRI) was performed postoperatively at an average of 6.5 months. Results: At a mean follow-up of 33.9 months (range, 25 to 42 months), 11 out of 12 patients were satisfied with their procedure. Patients showed significant improvement in their mean modified UCLA score from 15.9 preoperatively to 29.4 postoperatively (p=0.001). The mean KSS score improved from 45.6 preoperatively to 80.5 postoperatively (p=0.002). In MRI studies, 9 out of 12 patients had full incorporation of the graft into the native rotator cuff remnant. To date, there has been no intraoperative or postoperative complication from the graft procedure, such as infection or allograft rejection, in any patient. Conclusions: Arthroscopic bridging repair using a human dermis allograft can be considered as an option in treatment of select cases of massive irreparable rotator cuff tears, resulting in high patient satisfaction.

• Journal of Acupuncture Research
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• v.35 no.4
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• pp.238-243
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• 2018

Background: Various factors can alter the efficacy of acupuncture treatment, such as the location of points, manipulations, depth of insertion, needle retention time, and needle type. In this study, the effect of needle diameter on the efficacy of acupuncture treatment was quantitatively evaluated. Methods: Five acupuncture needles of different diameters used in clinical practice were compared. Force on the porcine tissue phantom was measured using a sensor. Lifting-thrusting and twisting-rotating movements were performed using a needle insertion-measurement system. After repeated measurements, force magnitude was calculated and compared. Following this, we correlated needle diameter and force magnitude during lifting-thrusting and twisting-rotating movements. Results: The force magnitude was significantly altered between needle diameters during lifting-thrusting movements, as shown by a significant positive correlation between needle diameter and force magnitude. In contrast, there was no difference in force magnitude with different needle diameters during twisting-rotating movements. Conclusion: Needle diameter can significantly affect stimuli and force magnitude dependent upon the type of manipulation. Research into the effect of other needle type characteristics and stimulation method is necessary to fully elucidate the role of acupuncture needle choice in treatment efficacy.

• Journal of the Korea Institute of Military Science and Technology
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• v.5 no.2
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• pp.185-194
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• 2002

To extract relative ranges from LOS(line of sight) information, we propose a passive ranging filter which is suitable for anti-ship missiles in HOJ(home on jam) mode. The proposed filter is devised to cope with the case that a passive ranging filter may include a large initial range estimation error since modem jammers are capable of very long range jamming. In addition, under the assumption that the missile motion is dominant over the HOJ engagement situation, the engagement geometry is modeled by a second order system. A new passive ranging filter is proposed by constructing an extended Kalman filter(EKF) based on the model. And then a least square initial state error estimation algorithm is attached to the EKF. Simulation results show that the proposed filter has a good range estimation performance with small computational load.

• Journal of Korean Neurosurgical Society
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• v.45 no.6
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• pp.381-385
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• 2009

The first case of intracranial metastases of a cervical intramedullary low-grade astrocytoma without malignant transformation in adult is presented in this report. Seven years ago, a 45 year-old male patient underwent biopsy to confirm pathologic characteristics and received craniocervical radiation and chemotherapy for a grade II astrocytoma in the cervical spinal cord. Two years later, posterior fusion was necessary for progressive kyphosis in the cervical spine. He was well for approximately 7 years after the primary surgery. Two months ago, he presented with partial weakness and incoordination with gait difficulty. MRI Scan demonstrated multiple small lesions in the cerebellar vermis and left hemisphere. After suboccipital craniectomy and posterior cervical exposure, the small masses in the cerebellar vermis and hemispheres were excised to a large extent by guidance of an intraoperative navigation system. The tumor at the cervical and brain lesions was classified as an astrocytoma (WHO grade II). When a patient with low-grade astrocytoma in the spinal cord has new cranial symptoms after surgery, radiaton, and chemotherapy, the possibility of its metastasis should be suspected because it can spread to the intracranial cavity even without malignant transformation as shown in this case.