• 제목/요약/키워드: Learning Curve

검색결과 421건 처리시간 0.037초

Unmanned Aircraft Systems in Construction and Agriculture: Uses, Benefits, Challenges, and Why Companies Choose to Invest

  • Pecoraro, James;Harper, Christofer;Wang, Chao
    • Journal of Construction Engineering and Project Management
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    • 제7권2호
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    • pp.34-44
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    • 2017
  • The use of Unmanned Aircraft Systems (UASs) in the construction and agriculture industries continues to gain in popularity and use. Firms within these industries have begun to utilize UASs to perform many of the traditional processes and procedures, which can result in a reduction in total work force and costs needed for a task. However, as with any technology, there is a learning curve and UASs do change the way certain activities are completed. Due to this, there exist firms and individuals that have not or are not willing to invest in UASs yet. The objective of this study is to explore the applications of UASs in construction and agricultural industries to discuss the benefits, challenges, and reasons of investing in UASs. This paper conducted an in-depth literature review of current topics on UASs in construction and agriculture. Additionally, six expert interviews were conducted with individuals from construction and agricultural industries in the southeastern United States. Ultimately, this study successfully found several benefits and challenges to using UASs and discussed the reasons that some firms invest in UASs while other still do not.

디지털 통신 시스템에서 데이터-재순환 LMS 알고리즘을 이용한 신호 간섭 제어 (Signal Interference Rejection using Data-Recycling LMS Algorithm in Digital Communication System)

  • 김원균;나상동
    • 한국통신학회논문지
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    • 제24권9A호
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    • pp.1329-1338
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    • 1999
  • 본 논문에서, LMS 알고리즘의 수렴 속도를 향상시키기 위한 효율적인 신호간섭 제어기법을 제안한다. 수신 데이터를 재활용하여 심볼 시간 주기에 계수들을 곱함으로써 적응되는 제안된 알고리즘의 수렴특성이 수렴 속도의 향상을 이론적으로 증명하기 위해 분석한다. 스텝-크기 매개변수 $\mu$가 증가됨에 따라 알고리즘의 수렴 속도가 제어된다. 또한, 스텝-크기 매개변수 $\mu$의 증가는 실험적으로 계산된 학습 곡선에서 분산을 감소시키는 효과를 갖는다. 고유치 확산을 증가시킴에 따라 적응 등화기의 수렴속도를 천천히 제어하고 평균 자승 에러의 안정-상태 값을 증가시키는 효과를 나타내며 데이터-재사용 LMS 기술이 수렴속도를 (B+1)배만큼 증가시켜 필터 알고리즘에서 신호간섭제어의 우수성을 입증한다.

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DEVELOPMENT OF A VIRTUAL FORGING FACTORY FRAMEWORK

  • Kao Yung-Chou;Sung Wen-Hsu;Huang Wei-Shin
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2003년도 The 8th Asian Symposium on Precision Forging ASPF
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    • pp.115-122
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    • 2003
  • This paper presents the development of a virtual forging factory framework. The technologies of virtual reality and relational database had been integrated in the developed framework using Microsoft $Windows^{(R)}$ programming as the main technique so as to emulate a physical forging factory. The developed virtual forging factory consists of forging cells and a forging cell is comprised of forging machine, forging die, and forging operations forming a forging production line. The technology of virtual reality had been successfully adopted in the production simulation of manufacturing such as CNC and robotics. However, the application in virtual forging factory seems to have not been studied yet. Potential application of a virtual forging factory can be beneficial to (1) computer aided instruction, (2) shorten the learning curve of a novice, (3) remote diagnosis and monitoring when remote monitoring and control technology and signal inspection is considered, (4) improve adverse forging environment when remote forging technology is applied, and (5) virtual reality application.

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Slow Feature Analysis for Mitotic Event Recognition

  • Chu, Jinghui;Liang, Hailan;Tong, Zheng;Lu, Wei
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제11권3호
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    • pp.1670-1683
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    • 2017
  • Mitotic event recognition is a crucial and challenging task in biomedical applications. In this paper, we introduce the slow feature analysis and propose a fully-automated mitotic event recognition method for cell populations imaged with time-lapse phase contrast microscopy. The method includes three steps. First, a candidate sequence extraction method is utilized to exclude most of the sequences not containing mitosis. Next, slow feature is learned from the candidate sequences using slow feature analysis. Finally, a hidden conditional random field (HCRF) model is applied for the classification of the sequences. We use a supervised SFA learning strategy to learn the slow feature function because the strategy brings image content and discriminative information together to get a better encoding. Besides, the HCRF model is more suitable to describe the temporal structure of image sequences than nonsequential SVM approaches. In our experiment, the proposed recognition method achieved 0.93 area under curve (AUC) and 91% accuracy on a very challenging phase contrast microscopy dataset named C2C12.

단일기관 소아환자에서 단일절개복강경하수술의 초기경험 (Early Experiences of Single Incision Laparoscopic Surgery in Pediatrics in a Single Center)

  • 송라영;정규환
    • Advances in pediatric surgery
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    • 제19권2호
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    • pp.90-97
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    • 2013
  • Laparoscopic surgery has become popular in the past few decades, owing to less postoperative pain, fast recovery, and better cosmetic outcomes. The laparoscopic approach has been employed in pediatric surgery for the same reasons. After the first attempts of single incision laparoscopic appendectomy in pediatrics in 1998, single incision laparoscopic surgery (SILS) has recently been proven to be safe and feasible for the pediatric population. However, limitations have been reported for SILS, such as the wide learning curve, compared to standard laparoscopic surgery, and the restricted number of hospitals with surgical training programs including SILS. In this study, we intend to present our initial experiences with SILS in children, and to describe the technique, instruments used, and outcomes. This is a retrospective study of 71 pediatric patients who underwent SILS, at a tertiary medical center, between September, 2012 and August, 2013. Electronic medical records were reviewed for demographics, type of procedure, operation time, use of additional ports, conversion to open surgery, complications and hospital stay. Additional ports were inserted in 4 cases, for the purpose of traction. Postoperative complications were noted in 13 cases, which were mostly related to wound inflammation or formation of granulation tissue. According to our analyses, patients with complications had significantly longer use and more frequent use of pain killers. Notwithstanding the small sample size, many of the procedures performed in pediatric patients seem to be possible with SILS.

Short Implant에 대한 문헌 고찰과 임상 적용 (Short Dental Implants : A Literature Review and Rationale for Use)

  • 김유리
    • 구강회복응용과학지
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    • 제25권3호
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    • pp.287-292
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    • 2009
  • 최근에는 임플란트를 이용한 치료가 예측 가능한 치료로 자리 잡고 있다. 충분한 골질과 골량은 임플란트의 성공에 중요한 역할을 한다. 10 mm 이하의 임플란트의 사용은 골질이 불충분할 때 부가적인 수술의 대안이 될 수 있다. 이 논문은 길이 10 mm 이하의 임플란트와 관련된 생역학적 관점과 발표된 임상결과들을 리뷰하고 사용 예지성을 제시하고자 하였다. 임플란트의 초기고정여부, 시술자의 learning curve, 사용한 임플란트의 표면처리, 환자의 골질들을 적절히 고려한 후 짧은 길이의 임플란트를 사용한다면 부가적인 수술 필요성의 대안이 될 수 있을 것이다.

Lateral override 과두하골절에서 내시경을 이용한 관혈적 정복술 및 내고정의 결과 (The result of endoscope-assisted open reduction and internal fixation (EAORIF) of lateral overridden subcondyle fracture)

  • 최은주;차인호;남웅
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • 제37권1호
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    • pp.62-66
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    • 2011
  • Introduction: Endoscope-assisted open reduction and internal fixation (EAORIF) reduces the amount of facial scaring, but limitations, such as the possibility to convert to the open technique and the large learning curve, remain. Materials and Methods: The medical records of 19 patients diagnosed as lateral overridden subcondyle fractures and treated with endoscope-assisted open reduction and internal fixation at Yonsei University Health System from December 2006 to August 2010 were reviewed. Results: 11 patients underwent temporary discomfort or pain such as limitation of mouth opening, temporomandibular joint discomfort, lip paresthesia or facial weakness, but the symptoms disappeared within 3 months. There was no severe long-term complication except 2 patients with re-fractures of operated subcondyles. Conclusion: Subcondyle fracture with lateral overridden proximal segment is a better indication of endoscope-assisted open reduction and internal fixation than a condylar head/neck fracture, or medial overridden subcondyle fracture: allowing an anatomic reduction.

대혈관 변위를 동반한 선천성 복잡심기형에 대한 동맥전환술 (Arterial switch operation for the complex congenital heart anomalies with malposition of the great arteries)

  • 이정렬
    • Journal of Chest Surgery
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    • 제26권1호
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    • pp.36-43
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    • 1993
  • Sixty four children [aged 2 days to 9 years] , 58 with complete transposition of the great arteries, 5 with Taussig-Bing double outlet right ventricle, and 1 with double outlet left ventricle plus left ventricular type single ventricle, have undergone anatomic correction from November 1987 to August 1992. Eleven underwent previous operations: pulmonary artery banding[7], modified Blalock-Taussig shunt[2], coarctoplasty[2], aortic arch reconstruction[1] . Of 58 patients with TGA, Type A coronary arteries of Yacoub were seen in 50[86%]. U-shaped coroanry arterial flaps were transfered to the neoaorta using trap door technique, and neopulmonary arterial tract was constructed using glutaraldehyde fixed autopericardium with Lecompte maneuver. There were 18 hospital deaths [28.1%] with no late mortality. Mean follow-up of 20.4\ulcorner11.9 months were achieved in all survivors. Postoperative cardiac catheterizations were done in 14 cases. Mean pressure gradients of pulmonary and aortic outflow tract were 15.0 $\pm$2.6 and 4.2$\pm$1.4mmHg, mild aortic valve insufficiencies were found in 2, and mean cardiac index was 5.18$\pm$0.19 L/min/M2. We conclude that we should continue anatomic correction for the complex congenital heart anomalies with the malposition of the great arteries because myocardial function seems to be well preserved, though we are still on the learning curve.

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Synthesis and Characterization of Nickel(II) Tetraaza Macrocyclic Complex with 1,1-Cyclohexanediacetate Ligand

  • Lim, In-Taek;Kim, Chong-Hyeak;Choi, Ki-Young
    • 대한화학회지
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    • 제62권6호
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    • pp.427-432
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    • 2018
  • The reaction of [$[Ni(L)]Cl_2{\cdot}2H_2O$ (L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo[$14,4,0^{1.18},0^{7.12}$]docosane) with 1,1-cyclohexanediacetic acid ($H_2cda$) yields mononuclear nickel(II) complex, [$Ni(L)(Hcda^-)_2$] (1). This complex has been characterized by X-ray crystallography, electronic absorption, cyclic voltammetry and thermogravimetric analyzer. The crystal structure of 1 exhibits a distorted octahedral geometry with four nitrogen atoms of the macrocycle and two 1,1-cyclohexanediacetate ligands. It crystallizes in the triclinic system P-1 with a = 11.3918(7), b = 12.6196(8), $c=12.8700(8){\AA}$, $V=1579.9(2){\AA}^3$, Z = 2. Electronic spectrum of 1 also reveals a high-spin octahedral environment. Cyclic voltammetry of 1 undergoes one wave of a one-electron transfer corresponding to $Ni^{II}/Ni^{III}$ process. TGA curve for 1 shows three-step weight loss. The electronic spectra, electrochemical and TGA behavior of the complex are significantly affected by the nature of the axial $Hcda^-$ ligand.

The supraclavicular artery island flap: a salvage option for head and neck reconstruction

  • Lee, Sanghoon;Cho, Hye-Min;Kim, Jin-kyu;Nam, Woong
    • Maxillofacial Plastic and Reconstructive Surgery
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    • 제40권
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    • pp.25.1-25.4
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    • 2018
  • Background: Some of head and neck cancer patients are in compromised general condition after ablation surgery and chemoradiation therapy, which makes secondary free tissue transfer quite challenging. Elderly cancer patients also have some risk for microvascular surgery with lengthened general anesthesia. In those cases, the pedicled flap vascularized by supraclavicular artery could be considered as an alternative to free flap. Despite several authors have demonstrated the clinical reliability of supraclavicular artery island flap (SCAIF), to date, SCAIF has not been widely used among reconstructive surgeon. In this article, we clarified vascular flow pattern and introduce simple surgical technique of SCAIF with a literature review. Case presentation: Three patients who had underwent previous neck surgery and adjuvant therapy received maxillofacial reconstruction using SCAIF. It required only a few landmarks, flap harvesting was carried out, and the elapsed time gradually decreased to 15 min with experiences. There were no remarkable morbidities in both donor and recipient sites. Conclusion: SCAIF exhibited minimal anatomic variations and short learning curve of surgical techniques, which might be valuable reconstruction modality for beginning surgeon. And it can be beneficial option for the patients with vessel-depleted neck, medically compromised status for lengthened general anesthesia and failed free tissue transfer.