• 제목/요약/키워드: multiple defects

검색결과 308건 처리시간 0.026초

회전기계 볼베어링의 자동진단 시스템에 관한 연구 (A Study on the Automatic Diagnosis System of Ball Bearings for Rotating Machinery)

  • 윤종호;김성걸;유정훈;이장무
    • 대한기계학회논문집
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    • 제19권8호
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    • pp.1787-1798
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    • 1995
  • Monitoring and diagnosis of the operating machine mean evaluating the condition of a machine such as the detection of the defects and the prediction of the time to failure in the machine elements, while it is running. In this study, a technique of automatic diagnosis using probability concept is studied and the analyses of the pattern comparison are introduced. An expert system, which is able to analyze the automatic identification of the multiple defects in the ball bearings, is also developed. Finally, to confirm the effectiveness of the programmed algorithms, some tests were made with specimens of the ball bearings involving the multiple defects. The proposed system reasonably predicts the defects.

Reconstruction of Large Facial Defects via Excision of Skin Cancer Using Two or More Regional Flaps

  • Lee, Dong Min;Bae, Yong Chan;Nam, Su Bong;Bae, Seong Hwan;Choi, June Seok
    • Archives of Plastic Surgery
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    • 제44권4호
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    • pp.319-323
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    • 2017
  • Background Free-flap surgery and skin grafting can be used to reconstruct large facial defects that may result after skin cancer removal by Mohs micrographic surgery (MMS). However, these two methods may produce low postsurgical patient satisfaction with aesthetics, and free-flap surgery may produce an undue burden for the majority of skin cancer patients, who are of advanced age. Hence, the authors examined outcomes of large facial defect reconstruction using multiple flaps. Methods Among patients undergoing MMS for skin cancer at Pusan National University Hospital between January 2013 and December 2015, we evaluated 7 patients (2 males, 5 females; average age, 73.14 years) treated for large facial defects from basal cell carcinoma. Based on operative and follow-up records, we investigated the number and type of flaps used, postsurgical complications, and patients' post-surgical satisfaction. Results Two and 3 types of flaps were used for 5 and 2 patients, respectively. Most frequently used were nasolabial flaps (7 times in 6 patients) and forehead flaps (once in each of 4 patients). The average follow-up period was 14 months, with no complications-including necrosis, hematoma, or wound dehiscence-observed. Post-surgical satisfaction averaged 4.4 out of a maximum of 5 points. Conclusions Reconstruction using two or more flaps for large facial defects after skin cancer removal using MMS produced satisfactory outcomes while preventing aesthetic problems. Practitioners should consider using multiple flaps when choosing a reconstruction method for large facial defects following skin cancer removal.

3D 유한요소법을 이용한 원전 매설배관 부식결함 탐상기술 개발 (Technology for the Detection of Corrosion Defects in Buried Pipes of Nuclear Power Plants with 3D FEM)

  • 김재원;임부택;박흥배;장현영
    • Corrosion Science and Technology
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    • 제17권6호
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    • pp.292-300
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    • 2018
  • The modeling of 3D finite elements based on CAD data has been used to detect sites of corrosion defects in buried pipes. The results generated sophisticated profiles of electrolytic potential and vectors of current distributions on the earth surface. To identify the location of defects in buried pipes, the current distribution on the earth surface was projected to a plane of incidence that was identical to the pipe locations. The locations of minimum electrolytic potential value were found. The results show adequate match between the locations of real and expected defects based on modeling. In addition, the defect size can be calculated by integrating the current density curve. The results show that the defect sizes were $0.74m^2$ and $0.69m^2$, respectively. This technology may represent a breakthrough in the detection of indirect damage in various cases involving multiple defects in size and shape, complex/cross pipe systems, multiple anodes and stray current.

다수의 고유 공간을 이용한 주화 표면 품질 진단 (Inspection of Coin Surface Defects using Multiple Eigen Spaces)

  • 김재민;류호진
    • 한국콘텐츠학회논문지
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    • 제11권3호
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    • pp.18-25
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    • 2011
  • 현재 주화의 제조 공정에서는 주화의 표면 품질 진단을 사람이 눈으로 직접 확인하여 수행하고 있다. 본 논문은 컨베이어 벨트에 놓이어 이동하는 주화로부터 획득한 영상을 이용하여 주화 표면의 결함을 검출하는 영상처리 방법을 제시한다. 결함 검출 방법은 영상에서 주화 영역을 분할하고, 분할된 동전을 비교할 모델에 정렬하며, 정렬된 영상을 최적의 고유 영상 공간으로 투영, 투영 오차와 학습된 가변 임계값과 비교하여 결함 부위를 검출한다. 본 논문에서는 이러한 일련의 영상처리 과정 중에서 주화 표면 진단과 관련하여 특화된 새로운 방법을 제시한다. 주화의 정렬을 위하여 분할된 주화의 히스토그램을 사용한다. 이 방법은 2차원 영상의 정렬을 일차원 히스토그램의 정렬로 변환하는 것이다. 다음으로 정렬된 영상을 고유 영상공간에 투영시켜 주화 방향에 따른 휘도 변화를 보정한다. 이 방법은 소수의 고유 영상 벡터들로 구성된 고유 영상 공간을 여러 개 생성하고, 최적의 고유 영상 공간에 정렬된 영상을 투영하여 실시간 구현이 가능하게 한다.

광범위 종양절제술 후 발생한 하악 결손의 재건 : 결손부위에 따른 비골 유리 피판의 다양한 디자인 (Reconstruction of Mandible Defect after Tumor Ablation Surgery : Versatility of Fibular Free Flap Design)

  • 설철환;이영대;탁관철;유대현
    • 대한두경부종양학회지
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    • 제21권2호
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    • pp.190-195
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    • 2005
  • Background and Objectives: Fibula is the flap of choice for reconstruction of wide mandible defects after tumor ablation surgery. In mandible reconstruction, restoring the mandible frame to provide mandibular contour and dental arch while restoring masticatory function are important. Even though vascularized fibula can be osteotomized freely, proper design and flap insetting is not easy because of its three dimensional structure and difference in design according to the defect sites. We reviewed patients who underwent mandible reconstruction with fibular flaps according to the defect sites and suggest proper modification methods of fibular flap according to the various defects sites after tumor ablation surgery. Materials and Methods: Twelve consecutive mandible reconstruction with fibular free flaps were performed for defects after tumor ablation surgery. Patients were classified into 4 groups according to the type of mandibular defect(Group 1 : defect on central segment including symphysis, Group 2 : defect on lateral segment(with or without central segment) confined to body, Group 3 : defect on body and ascending ramus that does not include the condyle, Group 4 : defect including the condyle). Results: We suggest different modification methods of fibular free flap for each patient group. Group 1, 3 ; contour by using multiple closing wedge osteotomy. Group 2 ; single or double barrel reconstruction without wedge osteotomy. Group 4 ; contour using single or multiple wedge osteotomy and condylar reconstruction with costochondral graft. Conclusion: Fibular free flaps can be contoured to any desired shape after multiple osteotomies to restore various mandibular defects. It is a reliable and versatile method for reconstruction of mandibular defects after tumor ablation surgery.

Treatment of Multiple Gingival Recessions Using Vestibular Incision Subperiosteal Tunnel Access with Platelet-rich Fibrin: Two Cases Reports

  • Sung-Min Hwang;Jo-Young Suh
    • Journal of Korean Dental Science
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    • 제16권2호
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    • pp.218-226
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    • 2023
  • Treatment of multiple gingival recession defects is usually more challenging than that of single gingival recession. Various techniques for the treatment of multiple gingival recession have been established. Recently, vestibular incision subperiosteal tunnel access (VISTA) technique has been considered to exhibit high predictive ability. Connective tissue graft (CTG) has also been considered a gold standard technique owing to its high predictability of root coverage. However, this technique requires a suitable donor site and has clinical disadvantages, such as additional pain. Thus, in this case presentation, platelet-rich fibrin (PRF) was used as an alternative material for CTG along with VISTA. We herein report cases of two patients with Miller's class I and III multiple gingival recession defects, respectively. These patients underwent VISTA along with the use of a PRF membrane. They were followed up for 12 months postoperatively, and their clinical parameters, including probing depth, depth of gingival recession, clinical attachment level, and width of attached gingiva at baseline and at 2, 6, and 12 months postoperatively, were assessed. The patient with class 1 recession defects exhibited a significant amount of root coverage, which remained stable during the follow-up period. Whereas the patient with class 3 recession defects had lesser amount of coverage compared to class 1 patient. The partial coverage observed may be attributed to not only anatomical factors but also the technique-sensitive nature of the procedure. Considering these results, the use of VISTA along with PRF is a viable option for treating gingival recession, as it does not cause discomfort to patients. However, various factors need to be considered during the surgical procedure.

화상 후 이개부 결손의 재건 (Reconstruction of Post Burn Auricular Defect)

  • 조동필;이종욱;고장휴;서동국;최재구;장영철
    • Archives of Plastic Surgery
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    • 제37권4호
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    • pp.421-426
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    • 2010
  • Purpose: Patients with serious burns are prone to chondritis due to lack of soft tissue in the auricle, which can cause severe defects in the auricular morphology. In addition, skin damage occurs frequently in the vicinity of post-burn wounds, presenting difficulties in reconstruction surgery. An auricular reconstruction has functional and cosmetic significance. The aim of this study is to develop appropriate reconstruction methods for auricular defects. Methods: Thirty seven patients, who were treated for auricular defects from 2005 to 2009, were enrolled in this study. A local flap, multiple regional flaps and cartilage framework with or without a temporal fascial flap were applied in reconstruction surgery according to the location of the auricular defect. Results: The age of the subjects ranged from 11 to 56. Some subjects had defects that cover more than half of the helical rim with most exhibiting post-burn scars in the vicinity, for whom a multiple regional flap was used. A single use of a tubed flap was sufficient for subjects with defects that covered less than half of the helical rim. A regional flap was also used for reconstruction in subjects with defects covering both the helical rim and antehelix. Conclusion: Achieving satisfactory results from the skin flaps and skin grafts for post-burn auricular defects in both functional and cosmetic aspects is a difficult task. Therefore, selecting an appropriate surgical method through proper diagnosis of the auricular defect and the state of the available skin in the vicinity is essential.

Theoretical Investigation of Edge-modified Zigzag Graphene Nanoribbons by Scandium Metal with Pyridine-like Defects: A Potential Hydrogen Storage Material

  • Mananghaya, Michael
    • Bulletin of the Korean Chemical Society
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    • 제35권1호
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    • pp.253-256
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    • 2014
  • Functionalization of zigzag graphene nanoribbon (ZGNR) segment containing 120 C atoms with pyridine (3NV-ZGNR) defects was investigated on the basis of density-functional theory (DFT) calculations, results show that edge-modified ZGNRs by Sc can adsorb multiple hydrogen molecules in a quasi-molecular fashion, thereby can be a potential candidate for hydrogen storage. The stability of Sc functionalization is dictated by a strong binding energy, suggesting a reduction of clustering of metal atoms over the metal-decorated ZGNR.

Fatigue life prediction of multiple site damage based on probabilistic equivalent initial flaw model

  • Kim, JungHoon;Zi, Goangseup;Van, Son-Nguyen;Jeong, MinChul;Kong, JungSik;Kim, Minsung
    • Structural Engineering and Mechanics
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    • 제38권4호
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    • pp.443-457
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    • 2011
  • The loss of strength in a structure as a result of cyclic loads over a period of life time is an important phenomenon for the life-cycle analysis. Service loads are accentuated at the areas of stress concentration, mainly at the connection of components. Structural components unavoidably are affected by defects such as surface scratches, surface roughness and weld defects of random sizes, which usually occur during the manufacturing and handling process. These defects are shown to have an important effect on the fatigue life of the structural components by promoting crack initiation sites. The value of equivalent initial flaw size (EIFS) is calculated by using the back extrapolation technique and the Paris law of fatigue crack growth from results of fatigue tests. We try to analyze the effect of EIFS distribution in a multiple site damage (MSD) specimen by using the extended finite element method (XFEM). For the analysis, fatigue tests were conducted on the centrally-cracked specimens and MSD specimens.

Selection of Tree History Management System Items for Analyzing the Causes of Landscape Tree Defects in an Apartment Complex

  • Park, Sang Wook
    • 인간식물환경학회지
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    • 제23권3호
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    • pp.347-362
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    • 2020
  • Background and objective: It is difficult to conclusively determine the exact cause of tree defects since multiple causes are involved such as climate change, plantation, tree quality and planting time, construction, planting base, drainage, sunshine conditions, maintenance, and microclimate. The data related to landscaping construction defects are scattered or fragmented by companies and years, but not managed systematically by the defect information management system. Most of the earlier studies associated with tree defects in apartment complexes suggested defect rates after examining tree defects in the completed construction site and proposed fragmentary and subjective conclusions about the causes of defects observed in trees with high defect rates. It is proposed to continue to conduct studies on the establishment and analysis of systematic databases to identify the exact causes of tree defects and measures to improve, and the need to accumulate systematic data in the construction process where many defects arises. This study was conducted to reduce the defects of trees planted in apartment complexes. Methods: Main factors related to tree defects were subdivided based on the results of literature review and a defect investigation at the completion site, and tree history management items were selected and subdivided during the construction stage. Results: The criteria for the preparation of subdivided items were obtained, and the tree history management checklist was written for the site under actual construction and a systematic database was established. Items that are categorized based to the causes of defects include the location of nurseries, date, tree quality, site conditions, planting techniques, microclimates, and maintenance. Conclusion: This study suggested tree history management items based on the tree defects that can be identified at the construction stage and applied them to the selected study site, which differentiates this study from earlier studies. It will be necessary to conduct a comprehensive and objective time series analysis on tree defects that occur over time by continuously monitoring and collecting data after construction.