• Imaging Science in Dentistry
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• 제40권3호
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• pp.123-129
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• 2010

Purpose : To evaluate the effect of surgical treatment of ligature-induced peri-implantitis in dogs using fractal analysis. Also, the capabilities of fractal analysis as bone analysis techniques were compared with those of histomorphometric analysis. Materials and Methods : A total of 24 implants were inserted in 6 dogs. After a 3-months, experimental periimplantitis characterized by a bone loss of about 3 mm was established by inducing with wires. Surgical treatment involving flap procedure, debridement of implants surface with chlorhexidine and saline (group 1), guided bone regeneration (GBR) with absorbable collagen membrane and mineralized bone graft (group 2), and $CO_2$ laser application with GBR (group 3) were performed. After animals were sacrificed in 8 and 16 weeks respectively, bone sections including implants were made. Fractal dimensions were calculated by box-counting method on the skeletonized images, made from each region of interest, including five screws at medial and distal aspects of implant, were selected. Results : Statistically significant differences in the fractal dimensions between the group 1($0.9340{\pm}0.0126$) and group 3($0.9783{\pm}0.0118$) at 16 weeks were found (P<0.05). The fractal dimension was statistically significant different between 8($0.9395{\pm}0.0283$) and 16 weeks in group 3 (P<0.05). These results were similar with the result of the evaluation of new bone formation in histomorphometric analysis. Conclusions : Treatment of experimental peri-implantitis by using $CO_2$ laser with GBR is more useful than other treatments in the formation of new bone and also the tendency of fractal dimension to increase relative to healing time may be a useful means of evaluating.

• 한국전자통신학회논문지
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• 제8권1호
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• pp.113-119
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• 2013

본 논문에서는 수 변전 설비의 열화진단을 위해서 열화상 카메라로 측정한 온도에 대한 시계열 데이터를 이용하여 포엔카레 맵과 프랙탈 차원에 의한 패턴 변화에 따른 온도 변화 특성을 살펴보았다. 시뮬레이션 결과 포엔카레 맵과 상관 차원에서 비선형적인 특성 거동을 확인할 수 있었다. 앞으로 추가적인 연구를 통한 검증 방법이 요구된다.

• 농업과학연구
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• 제41권4호
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• pp.379-384
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• 2014

In general, fractal analysis which is based on self-similarity as a basic theory has been mainly used to define the characteristics of complex mathematical figures, however, considering its basic theory, it can be also used to analyze the surface ununiformity of unknown materials. In this study, the soil samples were collected from the reclaimed (remodelled) agricultural fields which mean that the external soil is artificially piled up (mainly up to 1m) on the lands, Naju, Jellanam-do and Gumi, Gyeongsangbuk-do, and the conventional agricultural fields, Anseong, Gyeonggi-do and Hwasoon, Jellanam-do, and compared using fractal dimension analysis on the basis of the results of chemical properties. The score of fractal dimension ($D_0$) for organic matter was lower in Hwasoon (1.46) and Naju (1.58) than Anseong (1.86) and Gumi (1.96), and this trend showed similarly in soil pH. On the basis of the results of chemical properties, fine textured-soils (Hwasoon and Naju) and conventional agricultural fields were chemically uniform compared to coarse textured-soils (Anseong and Gumi) and the reclaimed. Therefore, it is required to develop technical methods for integrated soil management to the reclaimed lands.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.161-164
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• 1995

Nonlinear analysis of various phenomena has been developed with improvement of computer. The characteristics form nonlinear analysis are available in monitoring and diagnosis state of system. There are many nonlinear property in cutting process, but nonlinear signals have been considered as noise. In this study, nonlinear analysis technique is applied and it will be verified that cutting force is chaos by calculating Lyapunov exponents,fractal dimension and embedding dimension. The relation between characteristic parameter calculated form sensor signal and various cutting condition is investigated.

• KIEE International Transactions on Electrophysics and Applications
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• 제11C권2호
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• pp.18-22
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• 2001

The thin films of high permitivity in ferroelectric materials using a capacitor are applied to DRAMs and FRAMs. (Ba, Sr)TiO$_3$ thin as ferroelectric materials were prepared by the sol-gel method and made by spin-coating on the Pt/Sio$_2$/Si substrate at 4,000 [rpm] for 10 seconds. The structural characteristics of the surface were analyzed by fractal dimension. The thickness of BST ceramics thin films was about 260∼280 [nm]. The property of the leakage current was stable with 10-9∼10-11[A] when the applied voltage was 0∼3[V]. BST thin films ha low leakage current properties when fractal dimension was low and a coating area was high.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2001년도 학술발표회 발표논문집
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• pp.360-364
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• 2001

The fractal theory is an interesting tool for measuring the soil properties which are irregular and dynamical. A simple example is shown in this paper that (statistical) fractal dimension can be evaluated from the traditional Particle-size distribution(PSD) curve. The results of Wu et al.(1993) and Bittelli el al.(1999) were referred to demonstrate the fractal analysis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제37권6호
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• pp.477-482
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• 2011

Introduction: Bone regeneration of cystic defects of the jaws after a cyst treatment requires lengthy healing periods. Generally, the bony changes are observed periodically through a visual radiographic reading as well as by the clinical opinion and radiographic images (panorama, periapical view), but it is difficult to compare the objective bony changes using only the radiographic density. In addition, it is difficult to observe minute bony changes through a visual radiographic reading, which can lead to a subjective judgment. This study exmined the bone density after the enucleation of a jaw cyst by fractal analysis. Materials and Methods: Eighteen patients with a cystic lesion on the jaw were assessed. Panoramic radiographs were taken preoperatively, immediately postoperatively, and 1, 3, 6 and 12 months after cyst enucleation. The images were analyzed by fractal analysis. Results: The mean fractal dimensions increased immediately after surgery and 3, 6 and 12 months postoperatively. The postoperative 6 and 12 months fractal dimension was similar to the controls. Conclusion: Fractal analysis was used to overcome the limit of a subjective reading during an assessment of bone regeneration after cyst enucleation.

• 한국산학기술학회논문지
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• 제17권9호
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• pp.641-646
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• 2016

화석 연료의 연소 과정에서 발생하는 그을음 입자의 형상은 작은 구형입자들이 군집체를 이루고 있는 프랙탈 형상을 하고 있기에 기존 Rayleigh나 Mie 탄성 광 산란 이론으로 분석하는 것에는 한계가 있다. 본 논문에서는 Rayleigh-Debye Gans(RDG) 산란 이론을 적용하여 프랙탈 차원을 가지는 미세 입자의 형상을 효과적으로 해석할 수 있는 과정을 자세히 묘사하였다. 이소옥탄 확산 화염에서 발생하는 그을음 입자를 열 영동 채취법을 이용하여 채집한 후, 투과전자현미경을 이용하여 그을음 입자의 형상을 관찰하였다. RDG 산란 이론을 적용하여, 그을음 입자의 프랙탈 형상을 조사 하였고, 그을음 개별 입자의 직경, 입자 수밀도 및 부피 분율을 산출하였다. 이러한 결과들은 그을음의 성장 과정에서는 뚜렷한 증감 경향을 보이진 않았으나, 그을음 산화 과정에선 전부 뚜렷하게 감소하는 경향을 보였다. 본 연구에서 RDG 산란 이론을 이용하여 도출한 그을음 군칩체의 프랙탈 차원은 약 1.82로 이는 기존의 유사연구 결과와 동일하며, 화석연료의 종류에 상관없이 생성된 모든 그을음 입자에 동일한 값을 갖는 것으로 사료된다.

• 대한한의진단학회지
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• 제11권2호
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• pp.84-95
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• 2007

Background and Purpose: We have studied the trends of EEG signals in the voluntary breathing condition by applying the fractal analysis. According to chaos theory, irregularity of EEG signals can result from low dimensional deterministic chaos. A principal parameter to quantify the degree of Chaotic nonlinear dynamics is correlation dimension. The aim of this study was to analyze correlation between the correlation dimension of EEG and HRV(heart rate variability). We have studied the trends of EEG signals in the voluntary breathing condition by applying the fractal analysis. Methods: EEG raw data were measured by moving windows during 15 minutes. Then, the correlation dimension(D2) was calculated by each 40-seconds-segment in 15 minutes data, totally 36 segments. 8 channels EEG study on the Fp, F, T, P was carried out in 30 subjects. Results and Conclusion: Correlation analysis of HRV was calculated with deterministic non-linear data and stochastic non-linear data. 1. Ch1(Fp1), Ch4(F3), Ch4(F4) is positive correlated with In LF. 2. Ch1(Fp1), Ch3(F3) is positive correlated with In TF.

• KSBB Journal
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• 제10권2호
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• pp.119-125
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• 1995

균류를 이용하는 생물공정의 생산성, 분리성, 유변 학적 성질에 영향을 미치는 중요한 변수인 균류의 형태를 fractal 차원을 사용하여 정량화하였다. 산업적으로 중요한 균류인 Aspegillus oryzae와 Aspergil Ius niger가 초기의 접종 포자량과 탄소원의 놓도를 변화시켜 액상배지에서 성장하는 경우 디지탈 영상 분석장치를 사용하여 fractal 차원을 계산하였다. 균 샤가 형성하는 구체의 특성과 fractal로 표현된 균사 의 형태와의 상관관계를 구하였다. 일반적으로 낮은 fractal 차원의 균사가 낮은 밀도(compactness)의 구체를 형 성하고 외부의 모양이 불규칙 척 이 었다.