• Journal of Korean Neurosurgical Society
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• 제30권5호
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• pp.605-610
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• 2001

Objective : The authors investigated the efficacy of the calcium sulfate(OsteoSet$^{(R)}$ pellets) as an autograft extender when used to perform posterolateral lumbar fusions. Patients and Methods : Twenty patients who underwent lumbar posterolateral arthrodesis for various spinal diseases between October 1999 and March 2000 were evaluated. Arthrodesis was performed by transpedicular screw fixation and bone grafting with a mixture of autograft + calcium sulfate in a 1 : 1 ratio. At time intervals of 1, 2, 3, and 6 months, postoperative radiographs were obtained to review the resorption of calcium sulfate and the evidence of fusion. A modified Lenke scale was used to assess the status of the fusion. Results : At 2 months after operation, the average modified Lenke scale score for the OsteoSet$^{(R)}$ pellets group was 3.8. However at 6 months after operation, the average modified Lenke scale score for the OsteoSet$^{(R)}$ pellets group was 1.8. Resorption of calcium sulfate pellets was revealed in all cases at 6 months after surgery. Conclusion : It is presumed that a combination of calcium sulfate and autograft can play a role as an effective autograft extender in the posterolateral spinal fusion.

• Journal of Korean Neurosurgical Society
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• 제50권5호
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• pp.441-445
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• 2011

Objective : There are technical limitations of multi-level posterior pedicle screw fixation performed by the percutaneous technique. The purpose of this study was to describe the surgical technique and outcome of minimally invasive multi-level posterior lumbar interbody fusion (PLIF) and to determine its efficacy. Methods : Forty-two patients who underwent mini-open PLIF using the percutaneous screw fixation system were studied. The mean age of the patients was 59.1 (range, 23 to 78 years). Two levels were involved in 32 cases and three levels in 10 cases. The clinical outcome was assessed using the visual analog scale (VAS) and Low Back Outcome Score (LBOS). Achievement of radiological fusion, intra-operative blood loss, the midline surgical scar and procedure related complications were also analyzed. Results : The mean follow-up period was 25.3 months. The mean LBOS prior to surgery was 34.5, which was improved to 49.1 at the final follow up. The mean pain score (VAS) prior to surgery was 7.5 and it was decreased to 2.9 at the last follow up. The mean estimated blood loss was 238 mL (140-350) for the two level procedures and 387 mL (278-458) for three levels. The midline surgical scar was 6.27 cm for two levels and 8.25 cm for three level procedures. Complications included two cases of asymptomatic medial penetration of the pedicle border. However, there were no signs of neurological deterioration or fusion failure. Conclusion : Multi-level, minimally invasive PLIF can be performed effectively using the percutaneous transpedicular screw fixation system. It can be an alternative to the traditional open procedures.

• Journal of Korea Multimedia Society
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• 제17권8호
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• pp.968-976
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• 2014

Authentication methods on smartphone are demanded to be implicit to users with minimum users' interaction. Existing authentication methods (e.g. PINs, passwords, visual patterns, etc.) are not effectively considering remembrance and privacy issues. Behavioral biometrics such as keystroke dynamics and gait biometrics can be acquired easily and implicitly by using integrated sensors on smartphone. We propose a biometric model involving keystroke dynamics for implicit authentication on smartphone. We first design a feature extraction method for keystroke dynamics. And then, we build a fusion model of keystroke dynamics and gait to improve the authentication performance of single behavioral biometric on smartphone. We operate the fusion at both feature extraction level and matching score level. Experiment using linear Support Vector Machines (SVM) classifier reveals that the best results are achieved with score fusion: a recognition rate approximately 97.86% under identification mode and an error rate approximately 1.11% under authentication mode.

• Proceedings of the KIEE Conference
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.3044-3046
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• 2000

A Stereo matching has been an important tool for reconstructing three dimensional terrain. In this stereo matching process, DEM(Digitai Elevation Map) can be generated by the disparity from reference image to target image. Generally disparity map in matching process can be implemented by wraping from reference image to target image and if the role of reference and target is interchanged, the different DEM can be obtained. To evaluate the generated DEM from matching process, We adapted the Photorealistic synthetic image generator using ray tracing technique. The generator produce two simulated image from previous DEM and Ortho-image which is regard as Ground-truth. In this paper, we are concern about estimating more accurate DEM from these two DEMs. The several fusion methods of two DEMs are proposed to generate accurate DEM and compared with previous method. one of fusion methods is by using Cross-Correlation match score and the true DEM should have a high matching score.

• Journal of Korean Neurosurgical Society
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• 제53권4호
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• pp.223-227
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• 2013

Objective : Although there is no consensus on the ideal treatment of the craniocervical instability, biomechanical stabilization and bone fusion can be induced through occipito-cervical fusion (OCF). The authors conducted this study to evaluate efficacy of OCF, as well as to explore methods in reducing complications. Methods : A total of 16 cases with craniocervical instability underwent OCF since the year 2002. The mean age of the patients was 51.5 years with a mean follow-up period of 34.9 months. The subjects were compared using lateral X-ray taken before the operation, after the operation, and during last follow-up. The Nurick score was used to assess neurological function pre and postoperatively. Results : All patients showed improvements in myelopathic symptoms after the operation. The mean preoperative Nurick score was 3.1. At the end of follow-up after surgery, the mean Nurick score was 2.0. After surgery, most patients' posterior occipito-cervical angle entered the normal range as the pre operation angle decresed from 121 to 114 degree. There were three cases with complications, such as, vertebral artery injury, occipital screw failure and wound infection. In two cases with cerebral palsy, occipital screw failures occurred. But, reoperation was performed in one case. Conclusion : OCF is an effective method in treating craniocervical instability. However, the complication rate can be quite high when performing OCF in patients with cerebral palsy, rheumatoid arthritis. Much precaution should be taken when performing this procedure on high risk patients.

• The Journal of the Korea institute of electronic communication sciences
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• 제19권1호
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• pp.317-326
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• 2024

Biometric recognition is a technology that determines whether a person is identified by extracting information on a person's biometric and behavioral characteristics with a specific device. Cyber threats such as forgery, duplication, and hacking of biometric characteristics are increasing in the field of biometrics. In response, the security system is strengthened and complex, and it is becoming difficult for individuals to use. To this end, multiple biometric models are being studied. Existing studies have suggested feature fusion methods, but comparisons between feature fusion methods are insufficient. Therefore, in this paper, we compared and evaluated the fusion method of multiple biometric models using fingerprint, face, and iris images. VGG-16, ResNet-50, EfficientNet-B1, EfficientNet-B4, EfficientNet-B7, and Inception-v3 were used for feature extraction, and the fusion methods of 'Sensor-Level', 'Feature-Level', 'Score-Level', and 'Rank-Level' were compared and evaluated for feature fusion. As a result of the comparative evaluation, the EfficientNet-B7 model showed 98.51% accuracy and high stability in the 'Feature-Level' fusion method. However, because the EfficietnNet-B7 model is large in size, model lightweight studies are needed for biocharacteristic fusion.

• Journal of Korean Foot and Ankle Society
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• 제16권2호
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• pp.116-122
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• 2012

Purpose: Subtalar arthrodesis has been the gold standard for the painful subtalar joint disorders. Successful subtalar arthrodesis requires fusion of the 3 facet joints. The purpose of the study is to compare the clinical outcome of the posterior fixation (P2) and anterior-posterior (A1P1) fixation technique for subtalar arthrodesis which enhance anterior and middle facet fixation. Materials and Methods: The study is based on the 20 feet (19 patients) of the subtalar arthrodesis utilizing cannulated screws from September 2006 to September 2009 with at least 1-year follow-up. Two fixation techniques were utilized for the subtalar arthrodesis: 1) posterior fixation only (P2, 7 feet, 35%) and 2) anterior-posterior (A1P1) fixation method (13 feet, 65%). Visual Analog Scale Pain (VAS) score, American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score (maximum: 94 points), the time for returning to daily living and the patient satisfaction were also evaluated. Results: Average follow-up period were 13.2 months (12-3 mo). The AOFAS score improved from preoperative average 45 (0-68) to 81.6 (62-94), while VAS score was decreased from average 8.0 (3-10) to 1.8 (0-5) at final follow-up. Ninety-five percent of the patients were satisfied with surgery. All the patients returned to daily living at average 7.2 months (2-15 mo) post-surgery. Radiographically, 2 techniques both showed 100% fusion of the posterior compartment of the subtalar joint. Postoperative complications were 1 case of low grade infection and 1 case of sural nerve neuralgia. Conclusion: The subtalar arthrodesis using A1P1 fixation technique showed better fusion rate of the anterior compartment of the subtalar joint compared to P2 fixation technique although the 2 techniques both showed similar favorable clinical outcome. Therefore the A1P1 fixation technique is found to be a viable option to address chronic painful subtalar joint disorders to enhance the anterior compartment fixation.

• Journal of Korean Neurosurgical Society
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• 제46권1호
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• pp.45-51
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• 2009

Objective : To evaluate the potential effects of risedronate (RIS) which shows a higher anti-resorptive effect among bisphosphonates, after a posterolateral lumbar intertransverse process spinal fusion using both autograft and allograft in a rat model. Methods : A totoal of 28 Sprague-Dawley rats were randomized into 2 study groups. A posterolateral lumbar intertransverse process spinal fusion was peformed using both autograft and allograft in a rat model. Group I (control) received 0.1 mL of steril saline (placebo) and Group II (treatment) received risedronate, equivalent to human dose (10 ${\mu}g$/kg/week) for 10-weeks period. Results : The fusion rates as determined by manual palpation were 69% in the group I and 46% in the group II (p = 0.251). According to radiographic score, the spinal segment was considered to be fused radiographically in 7 (53%) of the 13 controls and 9 (69%) of the 13 rats treated with RIS (p = 0.851). The mean histological scores were 5.69 ${\pm}$ 0.13 and 3.84 ${\pm}$ 0.43 for the control and treatment groups, respectively. There was a significant difference between the both groups (p = 0.001). The mean bone density of the fusion masses was 86.9 ${\pm}$ 2.34 in the control group and 106.0 ${\pm}$ 3.54 in the RIS treatment group. There was a statistical difference in mean bone densities of the fusion masses comparing the two groups (p=0.001). Conclusion : In this study, risedronate appears to delay bone fusion in a rat model. This occurs as a result of uncoupling the balanced osteoclastic and osteoblastic activity inherent to bone healing. These findings suggest that a discontinuation of risedronate postoperatively during acute fusion period may be warranted.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• 제16권2호
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• pp.79-86
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• 2021

Objectives This study aimed to assess the role of complex Korean medicinal treatment with Chuna manual therapy in two patients with chronic pain after posterior lumbar fusion surgery. Methods A retrospective analysis was performed on 2 patients postoperatively based on their medical records. The surgery regions were verified using T2-weighted axial magnetic resonance imaging. Patients with chronic pain after spondylolisthesis posterior lumbar fusion surgery received complex Korean medicinal treatment with Chuna manual therapy during hospitalization. Numeric rating scale (NRS) in the degree of 0-10 and Oswestry disability index (ODI) were measured before and after treatment. Results Case 1 had an improved NRS score from 7 to 4, and Case 2 had an improved NRS score from 7 to 5. In addition, ODI score improved in both cases. Conclusions Complex Korean medicinal treatment with Chuna manual therapy is effective for relief from chronic pain after posterior lumbar fusion surgery.

• Journal of Korean Neurosurgical Society
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• 제44권4호
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• pp.217-221
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• 2008

Objective : Although anterior cervical discectomy and fusion (ACDF) is the standard treatment for degenerative cervical disc disease, concerns regarding adjacent level degeneration and loss of motion have suggested that arthroplasty may be a better alternative. We have compared clinical and radiological results in patients with cervical disc herniations treated with arthroplasty and ACDF. Methods : We evaluated 53 patients treated for cervical disc herniations with radiculopathy, 21 of whom underwent arthroplasty and 32 of whom underwent ACDF. Clinical results included the Visual Analogue Scale (VAS) score for upper extremity radiculopathy, neck disability index (NDI), duration of hospital stay and convalescence time. All patients were assessed radiologically by measuring cervical lordosis, segmental lordosis and segmental range-of-movement (ROM) of operated and adjacent disc levels. Results : Mean hospital stay (5.62 vs. 6.26 days, p<0.05) and interval between surgery and return to work (1.10 vs 2.92 weeks, p<0.05) were significantly shorter in the arthroplasty than in the fusion group. Mean NDI and extremity VAS score improved after 12 months in both groups. Although it was not significant, segmental ROM of adjacent levels was higher in the fusion group than in the arthroplasty group. And, segmental motion of operated levels in arthroplasty group maintained more than preoperative value at last follow up. Conclusion : Although clinical results were similar in the two groups, postoperative recovery was significantly shorter in the arthroplasty group. Although it was not significant, ROM of adjacent segments was less in the arthroplasty group. Motion of operated levels in arthroplasty group was preserved at last follow up.