• Journal of the Korean Orthopaedic Association
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• v.54 no.4
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• pp.336-342
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• 2019

Purpose: To examine the relationship between the progression of a kyphotic deformity and the magnetic resonance imaging (MRI) findings in conservatively treated osteoporotic thoracolumbar compression fracture patients. Materials and Methods: This study categorized the patients who underwent conservative treatment among those patients who underwent treatment under the suspicion of a thoracolumbar compression fracture from January 2007 to March 2016. Among them, this retrospective study included eighty-nine patients with osteoporosis and osteopenia with a bone density of less than -2.0 and single vertebral body fracture. This study examined the MRI of anterior longitudinal ligament or posterior longitudinal ligament injury, superior or inferior endplate disruption, superior of inferior intravertebral disc injury, the presence of low signal intensity on T2-weighted images, and bone edema of intravertebral bodies in fractured intravertebral bodies. Results: In cases where the superior endplate was disrupted or the level of bone edema of the intravertebral bodies was high, the kyphotic angle, wedge angle, and anterior vertebral compression showed remarkably progression. In the case of damage to the anterior longitudinal ligament or the superior disc, only the kyphotic angle was markedly prominent. On the T2-weighted images, low signal intensity lesions showed a high wedge angle and high anterior vertebral compression. On the other hand, there were no significant correlations among the posterior longitudinal ligament injury, inferior endplate disruption, inferior disc injury, and the progression of kyphotic deformity and vertebral compression. The risk factors that increase the kyphotic angle by more than 5° include the presence of injuries to the anterior longitudinal ligament, superior endplate disruption, and superior disc injury, and the risk factors were 21.3, 5.1, and 8.5 times higher than those of the uninjured case, and the risk differed according to the level of bone edema. Conclusion: An osteoporotic thoracolumbar compression fracture in osteoporotic or osteopenic patients, anterior longitudinal ligament injury, superior endplate and intravertebral disc injury, and high level of edema in the MRI were critical factors that increases the risk of kyphotic deformity.

• Composites Research
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• v.33 no.5
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• pp.302-308
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• 2020

We measured the thermal conductivity of composite materials manufactured by the autoclave and vacuum bag only processes and predicted the cure behavior of the external and internal of composite parts with a cure kinetics model. The temperature difference between the external and internal depends on the processes because of the change of thermal conductivity. In the autoclave process, the temperature and cure behavior of the internal were similar to those of the external because of the high thermal conductivity. However, the temperature of the internal of the vacuum bag only process was different from that of the external. The difference can influence the part quality and evacuation of air. Compression tests were performed to find the mechanical property using 0° unidirectional specimens. The composite of the vacuum bag only process was found to have a lower compressive strength than that of the autoclave process.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.155-158
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• 2008

In this paper, we propose a novel blind watermarking Method using 2D CAT (Two dimensional cellular automata transform). In our scheme, firstly, we obtain the gateway values to generate a dual-state, dual-coefficients basis function. Secondly, the basis function transforms images into cellular automata space. Lastly, we use the cellular automata transform coefficients to embed random noise watermark in the cover images. The proposed scheme allows only one 2D CAT basis function per gateway value. Since there are $2^{96}$ possible gateway values, better security is guaranteed. Moreover, the new method not only verifies higher fidelity than the existing method but also stronger stability on JPEG lossy compression, filtering, sharpening and noise through tests for robustness.

• Journal of Electrical Engineering and Technology
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• v.7 no.4
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• pp.646-651
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• 2012

Meaningful logos or random sequences have been used in the current digital watermarking techniques of 2D bar code. The meaningful logos can not only be created by copyright holders based on their unique information, but are also very effective when representing their copyrights. The random sequences enhance the security of the watermark for verifying one's copyrights against intentional or unintentional attacks. In this paper, we propose a new watermarking technique taking advantage of Data Matrix as well as encryption keys. The Data Matrix not only recovers the original data by an error checking and correction algorithm, even when its high-density data storage and barcode are damaged, but also encrypts the copyright verification information by randomization of the barcode, including ownership keys. Furthermore, the encryption keys and the patterns are used to localize the watermark, and make the watermark robust against attacks, respectively. Through the comparison experiments of the copyright information extracted from the watermark, we can verify that the proposed method has good quality and is robust to various attacks, such as JPEG compression, filtering and resizing.

• The Journal of the Korean bone and joint tumor society
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• v.5 no.1
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• pp.76-81
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• 1999

Aneurysmal bone cysts are uncommon bony lesions of the spine. Approximately 3-20% of the aneurysmal bone cysts occur in the spine, predominantly in the lumbar region, but they may occur at the any level of the spine. These lesions commonly arise from the neural arch and occasionally invade the pedicle and the vertebral body. The clinical diagnosis of a spinal lesion can be very difficult in the early stages of the disease because specific symptoms and signs are usually absent or only amount to back pain. However, depending on the level of involvement and the extent of neurological compression, a wide variety of neurological symptoms and signs may appear, ranging from mild radicular symptoms to complete paraplegia or tetraplegia. Available treatment options include complete excision or curettage of the lesion with bone graft, but where excision cannot be achieved, low dose radiation or arterial embolization may be used. We report a case of aneurysmal bone cyst in the pedicle of the T10 spine with nonstructural scoliosis of $40^{\circ}$ Cobb's angle which was treated successfully with only curettage of the lesion.

• Journal of the Korean Society for Heat Treatment
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• v.20 no.4
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• pp.175-180
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• 2007

The hardness of cold-forged products is in close relationship with its effective strain. This study presented the estimating method of hardness for cold-forged SKH9 products without hardness tests in view of resistance to plastic deformation using finite element code, DEFORM$^{TM}$. The flow stress equation obtained from the compression test was only used as a basic data to estimate the relationship between effective strain and hardness. In addition, this new estimating method was applied to the cold-forged product which was widely used in industrial field to show the feasibility. As a result, the predicted hardness numbers through FE simulation showed good agreement with the measured hardness numbers. It is possible to estimate the hardness not by hardness tests, but by only computer simulations for the deformed products. Also, effective strain values were possibly estimated by measuring hardness numbers, and vice versa.

• Journal of Korea Spatial Information System Society
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• v.11 no.4
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• pp.65-73
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• 2009

With the rapid development of computer, information and communication technologies, the production and distribution of digital contents among various kinds of networks have become more common. In such environment, we need to store and to manage efficiently a large volume of geograpruc data because the amount of geographic data grows faster and faster. In this paper, as a key solution to manage efficiently such a huge amount of geograpruc data, we adopt the mechanism which compresses only the difference between original and updated data with high compression ratio. By transferring highly compressed updated part only instead of the entire of geographic data, we can reduce the network traffic during the download of contents and service.

• Tuberculosis and Respiratory Diseases
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• v.72 no.5
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• pp.401-408
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• 2012

Cardiopulmonary resuscitation (CPR) is a series of life-saving actions that improve the chances of survival, following cardiac arrest. Successful resuscitation, following cardiac arrest, requires an integrated set of coordinated actions represented by the links in the Chain of Survival. The links include the following: immediate recognition of cardiac arrest and activation of the emergency response system, early CPR with an emphasis on chest compressions, rapid defibrillation, effective advanced life support, and integrated post-cardiac arrest care. The newest development in the CPR guideline is a change in the basic life support sequence of steps from "A-B-C" (Airway, Breathing, Chest compressions) to "C-A-B" (Chest compressions, Airway, Breathing) for adults. Also, "Hands-Only (compression only) CPR" is emphasized for the untrained lay rescuer. On the basis of the strength of the available evidence, there was unanimous support for continuous emphasis on high-quality CPR with compressions of adequate rate and depth, which allows for complete chest recoil, minimizing interruptions in chest compressions and avoiding excessive ventilation. High-quality CPR is the cornerstone of a system of care that can optimize outcomes beyond return of spontaneous circulation (ROSC). There is an increased emphasis on physiologic monitoring to optimize CPR quality, and to detect ROSC. A comprehensive, structured, integrated, multidisciplinary system of care should be implemented in a consistent manner for the treatment of post-cardiac arrest care patients. The return to a prior quality and functional state of health is the ultimate goal of a resuscitation system of care.

• KSBB Journal
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• v.26 no.5
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• pp.422-426
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• 2011

Alginate bead has been supplemented with various polymers to control permeability and to enhance mechanical strength. In this report, fibroin-reinforced alginate hydrogel was prepared, in which spatial localization of fibroin molecules was investigated. Confocal laser scanning microscopy revealed that fibroin molecules formed a fibrous network in the alginate-fibroin beads, which was expected to enhance mechanical strength as same as in many composite materials. Uniaxial compression test showed that fibroin-reinforced alginate beads had increased mechanical strength only after methanol treatment that caused ${\beta}$-sheet formation among fibroin molecules. Simultaneous curing and dialysis of alginate beads were carried out to remove excesscalcium but to retain fibroin in the dialysis chamber, which fabricated beads without internal fibrous fluorescent stains. Fibroin molecules were only found beneath the surface of the beads. The fibroin-diffused shell was further processed to form a thick wall after drying or was mobilizedto the centre of the bead by methanol treatment. Accordingly, the structure analyses provide processing methods of fibroin to form a wall or center clumps, which could be applied to design controlled delivery device.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1C
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• pp.105-112
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• 2009

In this paper, we propose a digital watermarking method using Multi-resolution Characteristic of 2D CAT (2D cellular automata transform). Firstly, we select the gateway values to generate a basis function and the basis function transforms images into cellular automata space. Then, we embed the random bit sequence as watermark in specific parts of cellular automata transform coefficients. The proposed method not only verifies higher fidelity than the existing method but also stronger stability on JPEG lossy compression, filtering, sharpening and noise through tests for robustness. Moreover, the proposed scheme allows only one 2D CAT basis function per gateway value. Since there are $2^{96}$ possible gateway values.