• The Korean Journal of Ecology
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• 제28권3호
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• pp.121-127
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• 2005

To reveal vegetation history and environmental changes in Mt. Jiri, sediment cores were collected from Wangdeungjae moor of Mt. Jiri. Overall dry matter accumulation rates and sedimentation rates by $^{14}C-dating$ were 0.027 $kg{\cdot}m^{-2}{\cdot}yr^{-1}$ and 0.184 mm/yr since 1250 ($760{\pm}40$ yrs BP, 14 cm in depth). There are three pollen zones; the first zone is below 14 cm depth where Quercus dominated, the second zone is from 14 cm to 6 cm depth where Gramineae increased and Quercus and Salix dominated and the third zone is from 6 cm depth to the top where Pinus and Quercus dominated. Total pollen concentration gradually increased from bottom to the top of sediment core, which implies wet, anaerobic and cool condition during covered period by the core. Calcium and magnesium contents had increased since 14 cm depth, with peaks at 13 and 20 cm depths. This indicates that groundwater had recently become relatively more important than surface water as water source of Wangdeungjae moor Exotic plant or Chenopodiacea pollen was less than 1%. There was little variation in total N and P contents along the length of the core. These results support that Wangdeungjae moor has been little affected by anthropogenic activities. Also, nutrients and heavy metal contents indicate the baseline condition of Wangdeungjae moor.

• Journal of Periodontal and Implant Science
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• 제53권2호
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• pp.120-134
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• 2023

Purpose: We investigated whether repeated irradiation with light-emitting diodes (LEDs) at a combination of 470 nm and 525 nm could suppress the progression of experimental periodontitis. Methods: A experimental periodontitis model was established in the second, third, and fourth premolars of the mandible in beagle dogs for 2 months. The spontaneous progression of periodontitis was monitored under the specified treatment regimen for 3 months. During this period, the animals were subjected to treatments of either plaque control only (control) or plaque control with LED application (test) at 2-week intervals. The clinical parameters included the probing pocket depth (PPD), gingival recession (GR), and the clinical attachment level (CAL). Histomorphometric analysis was performed using measurements of the length of the junctional epithelium, connective tissue (CT) zone, and total soft tissue (ST). Results: There were significant differences in PPD between the control and test groups at baseline and 12 weeks. When the change in PPD was stratified based on time intervals, it was shown that greater differences occurred in the test group, with statistical significance for baseline to 12 weeks, 6 to 12 weeks, and baseline to 6 weeks. There was no significant difference in GR between the control and test groups at any time points. Likewise, no statistically significant differences were found in GR at any time intervals. CAL showed a statistically significant difference between the control and test groups at baseline only, although significant differences in CAL were observed between baseline and 12 weeks and between 6 and 12 weeks. The proportion of CT to ST was smaller for both buccal and lingual areas in the control group than in the test group. Conclusions: Repeated LED irradiation with a combination of 470-nm and 525-nm wavelengths may help suppress the progression of periodontal disease.

• 정보처리학회논문지C
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• 제13C권3호
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• pp.283-294
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• 2006

악의적인 네트워크 트래픽은 흔히 공격의 성질을 구체적으로 알지 않고서도 평상시 트래픽과 구별된다. 본 논문에서는 네트워크 인바운드 트래픽 분포를 이용해 네트워크 트래픽 비정상행위를 탐지하는 방법을 제시한다. 이를 위해 먼저 실제 캠퍼스 네트워크의 트래픽 특성을 프로토콜, 패킷 길이, 목적지 IP/포트 주소, TTL 값, TCP SYN 패킷, 그리고 프래그멘트 패킷 분포 등을 통해 조사하였다. 이렇게 구해진 다양한 베이스라인 트래픽 분포로부터 엔트로피를 계산하고 이를 기준으로 비정상행위를 탐지하는 방법을 제시하였다. 특히 본 논문에서는 잘 알려진 서비스거부공격을 실제 캠퍼스 네트워크를 대상으로 실시하였고 그 결과를 제시함으로서 제안된 기법의 타당성을 검증하였다.

• 한국분무공학회지
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• 제17권2호
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• pp.94-99
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• 2012

The characteristics of spray behavior and injected amount were studied with two types of nozzles for using in a compression ignition engine with dual fuel technology for construction machines. A penetration length of spray tends to shorten due to a decrease of injected amount of a diesel fuel with dual fuel engine application. In order to ignite the gaseous fuel premixed with air during intake process, a diesel fuel, which was compression ignited, needs to penetrate somehow similar depth compared with the case of a diesel fuel-only-injection. In this work, a nozzle with reduced hole diameter and increased number of holes was tested and demonstrated that, compared to diesel 100% case, its penetration lengths are comparable to 74% and 79%, respectively, of those of 100% and 50% supply of a diesel fuel with the baseline nozzle that has four holes and 30.4% increased diameter. This will presumably enhancement the combustion in a dual fuel engine. A design suggestion was also made in this work to achieve similar penetration length of spray with diesel 100% case to prevent combustion from being deteriorated in a dual fuel engine.

• Journal of Korean Neurosurgical Society
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• 제59권5호
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• pp.478-484
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• 2016

Objective : To assess the clinical and radiological factors as predictors for successful outcomes in lumbar disc herniation (LDH) treatment. Methods : Two groups of patients with single level LDH (L4-5) requiring treatment were retrospectively studied. The surgery group (SG) included 34 patients, and 30 patients who initially refused the surgery were included in the nerve blocks group (NG). A visual analogue scale (VAS) for leg and back pain and motor deficit were initially evaluated before procedures, and repeated at 1, 6, and 12 months. Radiological factors including the disc herniation length, disc herniation area, canal length-occupying ratio, and canal area-occupying ratio were measured and compared. Predicting factors of successful outcomes were determined with multivariate logistic regression analysis after the optimal cut off values were established with a receiver operating characteristic curve. Results : There was no significant demographic difference between two groups. A multivariate logistic regression analysis with radiological and clinical (12 months follow-up) data revealed that the high disc herniation length with cutoff value 6.31 mm [odds ratio (OR) 2.35; confidence interval (CI) 1.21-3.98] was a predictor of successful outcomes of leg pain relief in the SG. The low disc herniation length with cutoff value 6.23 mm (OR 0.05; CI 0.003-0.89) and high baseline VAS leg (OR 12.63; CI 1.64-97.45) were identified as predictors of successful outcomes of leg pain relief in the NG. Conclusion : The patients with the disc herniation length larger than 6.31 mm showed successful outcomes with surgery whereas the patients with the disc herniation length less than 6.23 mm showed successful outcomes with nerve block. These results could be considered as a radiological criteria in choosing optimal treatment options for LDH.

• Journal of Korean Dental Science
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• 제16권1호
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• pp.23-34
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• 2023

Purpose: This study aims to investigate the force delivery profile of thermoformed aligners (TFA) compared with direct-printed aligners (DPA) and to explore the effect of different activation amounts on forces and moments of respective groups. A secondary objective is to observe the amount of stress relaxation that occurs over the 7~14 days when aligners are maintained in a simulated intraoral environment. Materials and Methods: An in vitro setup was created to quantify forces and moments. It consisted of a three dimensional-printed base plate and segmented maxillary teeth, placed in a semi-enclosed chamber to maintain a temperature of 37℃. Ninety clear aligners were divided into nine groups of ten aligners each based on material types (Zendura, ATMOS, TC-85) and activation amounts. Aligners were created with 0.00, 0.25- and 0.50-mm activations for lingual bodily movement of the upper left central incisor and kept on models in the "stressed" position in a 37℃ water bath. Three force components acting on the upper left lateral incisor, upper left central incisor, and upper right central incisor were measured for each time point, beginning from the initial baseline measurement, 8 hours, 16 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, and lastly, 14 days. Result: TC-85 aligners in every activation group showed less force on teeth than Zendura and ATMOS. Significant force levels from 0.0 mm activation were present and stayed consistent over the course of 14 days. Comparisons made for baseline measurements to 7-days and 14-days showed statistically significant change from the baseline force level. Conclusion: TC-85 aligners demonstrated lower, more consistent forces with fewer side effects. Aligners can generate forces even when no activation is programmed. No major decreases in force levels over time were observed; the intra-oral clinical simulated environment and length of observation time could contribute to this.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2010년 춘계학술발표회 논문집
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• pp.31-34
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• 2010

이중차분을 통한 GPS 측위시 이동국의 위치는 기준국에 대한 상대위치로 결정된다. 단기선의 경우는 조석에 의한 변위량의 상대적인 차이가 거의 없기 때문에 조석보정이 필요하지 않다. 하지만 기선의 길이가 길어지고 망 전체의 크기가 우리나라 전체 면적을 포함하는 경우 조석 변위량의 상대적인 차이로 인해 측위 오차가 발생할 수 있으므로 적절한 조석보정이 수반되어야 한다. 본 연구에서는 우리나라 규모에서 조석영향에 의해 발생할 수 있는 변위량을 분석하였다. 분석결과 GPS를 이용한 정밀측위시 조석영향에 대한 보정이 수행되어야 할 것으로 판단된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권7호
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• pp.1841-1857
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• 2023

CenterNet, a novel object detection algorithm without anchor based on key points, regards the object as a single center point for prediction and directly regresses the object's height and width. However, because the objects have different sizes, directly regressing their height and width will make the model difficult to converge and lose the intrinsic relationship between object's width and height, thereby reducing the stability of the model and the consistency of prediction accuracy. For this problem, we proposed an algorithm based on the regression of the diagonal half-length and the center angle, which significantly compresses the solution space of the regression components and enhances the intrinsic relationship between the decoded components. First, encode the object's width and height into the diagonal half-length and the center angle, where the center angle is the angle between the diagonal and the vertical centreline. Secondly, the predicted diagonal half-length and center angle are decoded into two length components. Finally, the position of the object bounding box can be accurately obtained by combining the corresponding center point coordinates. Experiments show that, when using CenterNet as the improved baseline and resnet50 as the Backbone, the improved model achieved 81.6% and 79.7% mAP on the VOC 2007 and 2012 test sets, respectively. When using Hourglass-104 as the Backbone, the improved model achieved 43.3% mAP on the COCO 2017 test sets. Compared with CenterNet, the improved model has a faster convergence rate and significantly improved the stability and prediction accuracy.

• 한국임상수의학회지
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• 제30권3호
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• pp.166-171
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• 2013

본 연구는 개에서 난소자궁절제술과 난소절제술의 실시가 동물의 통증행동과 스트레스에 미치는 영향을 비교하고, 임상적용 가능성을 평가하기 위하여 실시되었다. 13 마리의 건강한 암컷 중 (4.2-5.5 kg) 6 마리의 개에서 난소절제술이 행하여졌고, 7 마리에서 난소자궁절제술이 이루어졌다. 술 후 두 그룹 간에 수술 시간, 마취 시간, 복벽의 절개 길이를 비교하였다. 또한 술 전과 술 후 1, 2, 4, 6, 12, 24 시간째에 Short form of composite measure pain scale (CMPS-SF) 를 사용하여 통증 점수를 측정하였고 혈중 glucose 와 creatine kinase 그리고 cortisol 수치를 측정하였다. 난소자궁절제술을 시행한 그룹에서는 난소절제술을 시행한 그룹에 비해 유의적으로 (p < 0.05) 긴 수술 시간, 마취 시간, 복벽 절개 길이를 나타내었다. Two-way ANOVA test 결과 CMPS-SF에 의한 통증점수가 두 그룹 간에 유의적 (p < 0.05) 차이를 보였으며 술 후 1, 2, 4, 6 시간째 난소절제술을 행한 그룹에서 유의적으로 낮은 수치를 나타내었다. Glucose 의 경우 난소자궁절제술을 행한 그룹에서는 술 전과 비교해 유의적 (p < 0.05) 농도 증가가 술 후 1 시간째에 나타났으나 난소절제술을 행한 그룹에서는 술 후 전체 관찰기간 동안 유의적 농도 증가가 관찰 되지 않았다. Creatine Kinase 의 경우 난소자궁절제술을 행한 그룹에서는 술 전과 비교하여 술 후 1, 2, 4, 6, 12 시간째에 유의적 (p < 0.05) 농도 증가를 나타내었으나 난소절제술 그룹의 경우 술 후 4, 6, 12 시간째에만 술 전과 비교하여 유의적 (p < 0.05) 농도 증가를 나타내었다. Cortisol 의 경우 두 그룹 모두 술 후 1, 2 시간째에 유의적인 (p < 0.05) 농도 상승을 나타내었다. 본 연구 결과 난소절제술을 이용한 암캐의 중성화 수술 방법은 난소자궁절제술에 비해 짧은 복벽 절개, 수술 시간, 마취 시간을 요하며, 적은 술 후 통증과 스트레스를 유발하므로 난소절제술을 시행하는 것이 환자에게 바람직할 것으로 판단된다.

• Journal of Korean Neurosurgical Society
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• 제64권1호
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• pp.78-87
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• 2021

Objective : Intraoperative neurophysiological monitoring (IONM) has been widely used during spine surgery to reduce or prevent neurologic deficits, however, its application to the surgical management for cervical myelopathy remains controversial. This study aimed to assess the success rate of IONM in patients with cervical myelopathy and to investigate the factors associated with successful baseline monitoring and the effect of increasing the stimulation intensity by focusing on motor evoked potentials (MEPs). Methods : The data of 88 patients who underwent surgery for cervical myelopathy with IONM between January 2016 and June 2018 were retrospectively reviewed. The success rate of baseline MEP monitoring at the initial stimulation of 400 V was investigated. In unmonitorable cases, the stimulation intensity was increased to 999 V, and the success rate final MEP monitoring was reinvestigated. In addition, factors related to the success rate of baseline MEP monitoring were investigated using independent t-test, Wilcoxon rank-sum test, chi-squared test, and Fisher's exact probability test for statistical analysis. The factors included age, sex, body mass index, diabetes mellitus, smoking history, symptom duration, Torg-Pavlov ratio, space available for the cord (SAC), cord compression ratio (CCR), intramedullary increased signal intensity (SI) on magnetic resonance imaging, SI length, SI ratio, the Medical Research Council (MRC) grade, the preoperative modified Nurick grade and Japanese Orthopedic Association (JOA) score. Results : The overall success rate for reliable MEP response was 52.3% after increasing the stimulation intensity. No complications were observed to be associated with increased intensity. The factors related to the success rate of final MEP monitoring were found to be SAC (p<0.001), CCR (p<0.001), MRC grade (p<0.001), preoperative modified Nurick grade (p<0.001), and JOA score (p<0.001). The cut-off score for successful MEP monitoring was 5.67 mm for SAC, 47.33% for the CCR, 3 points for MRC grade, 2 points for the modified Nurick grade, and 12 points for the JOA score. Conclusion : Increasing the stimulation intensity could significantly improve the success rate of baseline MEP monitoring for unmonitorable cases at the initial stimulation in cervical myelopathy. In particular, the SAC, CCR, MRC grade, preoperative Nurick grade and JOA score may be considered as the more important related factors associated with the success rate of MEP monitoring. Therefore, the degree of preoperative neurological functional deficits and the presence of spinal cord compression on imaging could be used as new detailed criteria for the application of IONM in patients with cervical myelopathy.