• Journal of information and communication convergence engineering
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• 제21권3호
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• pp.225-232
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• 2023

Owing to advancements in intelligent transportation systems (ITS) and artificial-intelligence technologies, various machine-learning models can be employed to simulate and predict the number of traffic accidents under different weather conditions. Furthermore, we can analyze the relationship between weather and traffic accidents, allowing us to assess whether the current weather conditions are suitable for travel, which can significantly reduce the risk of traffic accidents. In this study, we analyzed 30000 traffic flow data points collected by traffic cameras at nearby intersections in Washington, D.C., USA from October 2012 to May 2017, using Pearson's heat map. We then predicted, analyzed, and compared the performance of the correlation between continuous features by applying several machine-learning algorithms commonly used in ITS, including random forest, decision tree, gradient-boosting regression, and support vector regression. The experimental results indicated that the gradient-boosting regression machine-learning model had the best performance.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제20권2호
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• pp.112-126
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• 1998

In dentistry, bony defects can be formed by cyst, tumor, inflammation, trauma and surgery in maxilla and mandible. If the overlying soft tissue invades and preoccupies the jaw bony defects, regenerated bony tissue same as adjacent bone can not replace whole space of the defects, thus preventing osteogenesis from occurring. Guided bone regeneration(GBR) is based on the prevention of overlying soft tissue from entering the bony defect during the initial healing periods. E-polytetrafluoroethylene(e-PTFE) is one of an effective and widely used barrier membrane for GBR, but it has the disadvantages such as surgical removal and high price. To overcome such disadvantages of e-PTFE, many investigators have proposed various absorbable barrier membranes. Inexpensive oxidized cellulose($Surgicel^{(R)}$) membrane was shown to have potential for use as an absorbable barrier membrane for regenerative procedure and it would not require surgical removal. The purpose of this study is to investigate the absorption periods of oxidized cellulose at the implant site and usefulness as a mechanical barrier, preventing the ingrowth of the overlying soft tissue into the bony defects. Two bony defects were made in each tibia of a dog using drill and one defect covered with oxidized cellulose and the other covered with periosteum directly as control. The experimental animals were sacrificed at 1st-7th, 10th, 14th, 21th, 28th day postoperatively, Inspection of the specimens was done to evaluate gross changes. Specimens were examined histopathologically by hematoxylin-eosin and Masson's trichrome staining under light microscope. The results were as follows : 1. There was no significant differences of inflammatory reaction between the experimental and the control group. 2. The resorption of oxidized cellulose was almost completed within 14th day. 3. Histologically, bone formation in the experimental group was somewhat more than that of the control group at 10th, 14th, 21th and 28th day postoperatively. The bone forming pattern of the experimental group was more regular than that of the control group. 4. There was no evidence of soft tissue invasion into the bony defect in the experimental group. In conclusion, oxidized cellulose membrane might be used as an alternative absorbable barrier membrane to prevent overlying soft tissue invasion into the bony defects.

• 한국지구과학회지
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• 제36권4호
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• pp.330-340
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• 2015

본 연구에서는 CCD 카메라가 장착된 Skyviewer로부터 촬영된 하늘 영상 자료를 이용하여 전운량을 산출하는 알고리즘을 개발하였다. 전운량 산출은 RGB 영상 내의 차폐 영역을 제거하고 GBR 빈도분포에 따른 영상을 분류하며, RBR 경계값을 결정하여 구름 화소를 분류한다. 분류된 구름 화소에서 태양광 영역을 제거한 후 유효성 검사를 통해 전운량을 산출하게 된다. 전운량 산출 알고리즘의 정확성을 검증하기 위하여 관측소와 가장 가까운 강원지방기상청의 목측 전운량 자료와 편이(Bias), 평균제곱근오차(RMSE), 상관계수를 분석하였다. 선정된 사례는 계절별 일 사례로 8시부터 17시까지의 정시 자료를 사용하였다. 분석 결과 Skyviewer로부터 산출된 전운량의 편이는 평균적으로 -0.8할의 차이를 보였으며, 평균제곱근오차는 1.6할로 전운량의 차이가 2할 내에서 나타나고 있었다. 또한, 두 관측소는 떨어진 거리의 차이가 있음(약 4 km)에도 불구하고 상관계수가 모든 사례에서 평균 0.91 이상으로 매우 높았다.

• 대한핵의학회지
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• 제31권4호
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• pp.421-426
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• 1997

[$^{18}F$]FMBS는 도파민 $D_2$ 수용체 방사성추적자로서 유망한 성질을 지니고 있다. [$^{18}F$]FMBS는 비교적 높은 특이결합/비특이결합 비를 제공하며, 그 체내결합은 도파민 $D_2$ 수용체에 대하여 높은 특이성과 선택성을 보인다. 도파빈 $D_2$ 수용체 측정을 위한 보다 적합한 PET 방사성추적자를 얻기 위해서는 [$^{18}F$]FMBS의 낮은 뇌섭취와 느린 역학을 개선할 수 있는 화학적 구조의 변형이 시도되어야 하며, [$^{18}F$]FMBS는 이러한 시도의 골격이 될 수 있을 것으로 믿는다.

• 식물병연구
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• 제20권3호
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• pp.227-233
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• 2014

초산(acetic acid)과 젖산(lactic acid)의 혼합액(MX)의 심비디움 배양토에 오염된 소나무재선충(Bursaphelenchus xylophilus)의 방제효과를 조사하였다. 실내실험에서 초산과 혼합액은 5.0-1.0% (pH 2.6-4.2)에서 젖산은 5.0%에서만 100%가까운 살선충율을 나타내었고 이보다 낮은 농도(0.5-0.1%, pH 5.1-6.9)에서는 초산과 혼합액보다 젖산에서 살선충력이 유의적으로 낮아졌다. 대부분의 농도에서 혼합액의 살선충율이 초산과 젖산의 평균보다 유의적으로 높게 나타나 혼합액의 살선충력 상승효과가 있을 것으로 판단된다. 폿트실험에서 유기산 혼합액(0.5%, 0.25%), 살선충제(fosthiazate, 표준량, 배량) 및 길항세균(Paenibacillus polymyxa GBR-1) 배양 희석액($10^7CFU/ml$) 등의 처리에 의해 심비디움 배양토에서의 소나무재선충의 밀도가 처리간에는 유의적인 차이가 없이 무처리에 비해 유의적으로 감소하였다. 모든 처리에서 약해가 나타나지 않았고, 처리 후 시기별 pH와 2년생 심비디움의 생육에 무처리 대조구와 유의적인 차이가 나타나지 않았다. 이러한 결과와 이들 식용 유기산의 안전성과 가격을 종합하여 볼 때, 심비디움의 재배 관리 중 생육단계에 따라 이 유기산 혼합액의 지속적인 사용은 검역해충의 방제에 있어서 친환경적이고 실제적으로 유효한 하나의 방법일 것이다.

• Journal of Periodontal and Implant Science
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• 제42권6호
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• pp.231-236
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• 2012

Purpose: The aim of this study was to evaluate the influence of the crown-to-implant (C/I) ratio on the change in marginal bone level around the implant and to determine the site-related factors influencing the relationship between the C/I ratio and periimplant marginal bone loss. Methods: A total of 259 implants from 175 patients were evaluated at a mean follow-up of five years. Implants were divided into two groups according to their C/I ratios: ${\leq}$ 1, and >1. Site-related factors having an influence on the relationship between C/I ratio and periimplant marginal bone loss were analyzed according to the implant location, implant diameter, implant manufacturer, prosthesis type, and guided bone regeneration (GBR) procedure. Results: It was found that 1) implants with a C/I ratio below 1 exhibited greater periimplant marginal bone loss than implants with a C/I ratio more than 1, 2) site-related factors had an effect on periimplant marginal bone loss, except for the implant system used, 3) the C/I ratio was the factor having more dominant influence on periimplant marginal bone loss, compared with implant diameter, prosthesis type, implant location, and GBR procedure, 4) implants with a C/I ratio below 1 showed greater periimplant marginal bone loss than implants with a C/I ratio greater than 1 in the maxilla, but not in the mandible, 5) and periimplant marginal bone loss was more affected by the implant system than the C/I ratio. Conclusions: Within the limitations of this study, implants with a higher C/I ratio exhibited less marginal bone loss than implants with a lower C/I ratio in the posterior regions. The C/I ratio was a more dominant factor affecting periimplant marginal bone loss in the maxilla than the mandible. Meanwhile, the implant system was a more dominant factor influencing periimplant marginal bone loss than the C/I ratio.

• Journal of Periodontal and Implant Science
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• 제37권2호
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• pp.237-249
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• 2007

This study was performed to evaluate the effect of membrane exposure on new bone formation when guided bone regeneration with perforated titanium membrane on atrophic alveolar ridge. The present study attempted to establish a GBR model for four adult beagle dog premolar. Intra-marrow penetration defects were created on the alveolar ridge(twelve weeks after extraction) on the mandibular premolar teeth in the beagle dogs. Space providing perforated titanium membrane with various graft material were implanted to provide for GBR. The graft material were demineralized bovine bone(DBB), Irradiated cancellous bone(ICB) and demineralized human bone powder(DFDB). The gingival flap were advanced to cover the membranes and sutured. Seven sites experienced wound failure within 2-3weeks postsurgery resulting in membrane exposure. The animals were euthanized at 4 weeks postsurgery for histologic and histometric analysis. The results of this study were as follows: 1. There was little new bone formation at 4 weeks postsurgery. irrespectively of membrane exposure. 2. There was significant relationship between membrane exposure and bone graft resorption(P<0.05), but no relation between membrane exposure and infiltrated connective tissue. 3. There was much bone graft resorption on DFDB than ICB and DBB. 4. The less exposure was on the perforated titanium membrane, the more dense infiltrated connective tissue was filled under the membrane when grafted with ICB and DBB. but there was no relationship between the rate of membrane exposure and the percentage of infiltrated connective tissue area and no relationship between the percentage of the area in the infiltrated connective tissue and in the residual bone graft. Within the above results, bone formation may be inhibited when membrane was exposed and ICB and DBB were more effective than DFDB as a bone graft material when guided bone regeneration.

• 한국식품저장유통학회지
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• 제14권3호
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• pp.276-280
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• 2007

전통 올벼쌀의 품질특성 측정 결과 수분은 12.7%, 조지방, 회분, 조단백 함량은 1.0%, 0.9%, 6.3%로 측정되었다. 전체적인 색차이를 보기 위한 ${\Delta}E$값은 올벼쌀이 43.0로 다른 시료보다 높은 값을 나타내어 표준색판과 색의 차이가 가장 큰 것으로 측정되었다. 올벼쌀의 수분흡수지수는 침지초기에 급격히 증가하는 양상을 보였다. 침지 5분만에 4.76 g/g 수준으로 건조햇반 3.34 g/g에 비해 상당히 빠른 흡수속도를 나타내었고, 침지시간이 증가함에 따라 흡수량도 현저히 증가하였다. 올벼쌀은 시간이 증가할수록 수분 용해지수도 증가하여 40분 후 수분용해지수가 4.75%로 가장 높은 값을 보여 전분 용출이 많은 것으로 판단된다. 경도 측정 결과 건조햇반 7.0 $kg_f$, 찰현미 8.9 $kg_f$, 올벼쌀 10.5 $kg_f$, 발아현미 7.5 $kg_f$로 측정되어 다른 시료보다 높은 경도를 나타냈다. 올벼쌀의 호화특성 측정결과 호화개시온도가 $39.5^{\circ}C$로 다른 시료보다 낮은 값을 나타내어 초기호화가 빨리 시작됨을 알 수 있었다. 결과적으로 올벼쌀과 건조햇반, 발아현미, 찰현미는 다른 품질특성을 나타내므로 올벼쌀을 이용한 가공제품 개발시 기존과 다른 가공기술을 이용해야 할 것으로 판단된다.

• 한국식품과학회지
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• 제50권6호
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• pp.608-613
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• 2018

점도 상승 효과와 열량 및 영양성분의 섭취량 증가를 목적으로 고아미, 찰보리, 발아현미, 귀리 등 4종 곡류를 이용, 시판 증점제와 유사한 점도를 갖는 첨가량을 결정하고, 시료의 점도, 색도, 관능적 특성 등을 평가하였다. 곡류들 중, 찰보리가 가장 높은 호화 점도 특성을 보였으며, 고아미가 가장 낮은 특성을 보였다. 색도측정 결과 고아미는 명도가 가장 높았고, 귀리나 발아현미는 황색도가 높아 첨가한 시료의 노란색이 두드러지는 특성을 보였다. 시판 증점제 첨가량을 기준으로 분산매인 흰쌀죽 시료의 점도를 비교한 결과, 시판 증점제 0.5포 첨가 점도, 즉 1단계 점도를 얻기 위해서는 고아미 3%, 찰보리 3%, 발아현미 4%, 귀리 3.5%를 첨가해야 하고, 시판 증점제 1포에 해당하는 점도 2단계에 도달하려면 고아미 6%, 찰보리 4%, 발아현미 5.5%, 귀리 5%를, 2포에 해당하는 점도 3단계는 고아미 7%, 찰보리 5.5%, 발아현미 6%, 귀리 6.5%를 첨가해야 도달할 수 있었다. 온도에 따라 증점제 첨가시료의 점도는 달라졌으나, 배식과 섭취온도를 고려한 $55-60^{\circ}C$에서는 시판 증점제를 대체하기에 충분한 점도를 보였다. 관능검사결과 전체적 선호도는 주로 색에 기인하였으며, 다른 요인들은 관능적 특성에 차이가 없는 것으로 나타났기 때문에 감각적 특성이 20-30대보다 민감하지 않은 연하곤란자(주로 노인)의 경우, 그 차이가 적을 수 있어 본 실험에서 사용한 곡류 가루들은 충분히 시판 증점제를 대체할 수 있을 것으로 생각된다.

• Journal of Periodontal and Implant Science
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• 제53권4호
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• pp.306-317
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• 2023

Purpose: Biphasic calcium phosphate (BCP), a widely used biomaterial for bone regeneration, contains synthetic hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), the ratio of which can be adjusted to modulate the rate of degradation. The aim of this study was to evaluate the clinical and radiographic benefits of reconstructing peri-implant bone defects with a newly developed BCP consisting of 60% β-TCP and 40% HA compared to demineralized bovine bone mineral (DBBM). Methods: This prospective, multicenter, parallel, single-blind randomized controlled trial was conducted at the periodontology departments of 3 different dental hospitals. Changes in clinical (defect width and height) and radiographic (augmented horizontal bone thickness) parameters were measured between implant surgery with guided bone regeneration (GBR) and re-entry surgery. Postoperative discomfort (severity and duration of pain and swelling) and early soft-tissue wound healing (dehiscence and inflammation) were also assessed. Data were compared between the BCP (test) and DBBM (control) groups using the independent t-test and the χ² test. Results: Of the 53 cases included, 27 were in the test group and 26 were in the control group. After a healing period of 18 weeks, the full and mean resolution of buccal dehiscence defects were 59.3% (n=16) and 71.3% in the test group and 42.3% (n=11) and 57.9% in the control group, respectively. There were no significant differences between the groups in terms of the change in mean horizontal bone augmentation (test group: -0.50±0.66 mm vs. control groups: -0.66±0.83 mm, P=0.133), postoperative discomfort, or early wound healing. No adverse or fatal complications occurred in either group. Conclusions: The GBR procedure with the newly developed BCP showed favorable clinical, radiographic, postoperative discomfort-related, and early wound healing outcomes for peri-implant dehiscence defects that were similar to those for DBBM.