• Title/Summary/Keyword: pitfalls

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Socket lifting을 이용한 자가치아 이식

  • Kim, Yeong-Un
    • The Journal of the Korean dental association
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    • v.40 no.9 s.400
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    • pp.697-702
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    • 2002
  • Tooth autotransplantation using socket lifting like this case had been seldom reported. So this report demonstrates a case using this technique which is frequently used for maxillary posterior implantation. Clinical considerations and pitfalls will be discussed.

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MR Arthrography of the Labral-Capsular-Ligamentous Complex: Normal Variations and Pitfalls (관절와순낭인대(Labral-Capsular-Ligamentous) 복합체의 자기공명관절 조영술 : 정상변이 및 진단시 주의점)

  • Han Sung Ho;Yang Bo Kyu;Kim Chi Hong;Ahn Tae Won;Chu Wu Jun
    • The Academic Congress of Korean Shoulder and Elbow Society
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    • 1997.05a
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    • pp.164-166
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    • 1997
  • MR arthrography is a useful modality for evaluating the labrocapsular ligamentous complex(LOLC) of the shoulder. This study was performed to describe normal anatomic variations and pitfalis in image interpretation related to evaluation of the LOLC. MR Arthrogram of 56 shoulders in 41 asymptomatic young, active volunteers were prospectively reviewed to evaluate the labral shapes. capsular insertions and images which may mimic the lesions of glenohumoral instability. The anterior and posterior parts of the labra. respectively. varied in shape: triangular$(72\%,\; 36\%)$. round $(13\%,\; 35\%)$. cleaved$(8\%,\; 1\%)$. notched$(2\%,\; 0\%)$. flat$(5\%,\; 24\%)$ and absent$(0\%,\; 4\%)$. The anterior and posterior capsular insertions. respectively. varied in sites: Mosely and Oevergaard type I$(82\%,\;62\%)$, type II$(13\%,\; 3\%)$ and type III $(5\%,\; 2\%)$. A number of pitfalls in image interpretation were discovered. Articular cartilage undercutting the labrum$(29\%)$ and middle glenohumoral ligament in proximity to anterior labrum $(5\%)$ simulated a labral tear. Joint fluid interposed in the central. superior portion of the sublabral sulci$(25\%)$ simulated a SLAP lesion. Synovial fold$(38\%)$ in axillary pouch resembled a loose body. Knowledge of normal variations and pitfalls in MR arthrogram image interpretation of labral capsular - ligamentous complex will help the orthopedist to accurately detect debilitating derangements associated with the glenohumeral instability.

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The misusage of statistical methods in Six Sigma projects (6시그마 프로젝트에서의 통계기법의 오용)

  • 안병진
    • Journal of Korean Society for Quality Management
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    • v.31 no.3
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    • pp.172-184
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    • 2003
  • Many companies in Korea are paying close attention to Six Sigma to get better business results. And there are numerous success stories on the use of statistical methods in solving problems, improving processes and cutting costs. However, there are many cases in which statistical methods are misused or inappropriately applied. In this paper, the pitfalls to avoid in using statistical methods are discussed. Also the role of statistics in Six Sigma is examined.

Pitfalls in the Application of the COTE in a Linear Regression Model with Seasonal Data

  • Seuck Heun Song;YouSung Park
    • Communications for Statistical Applications and Methods
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    • v.4 no.2
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    • pp.353-358
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    • 1997
  • When the disturbances in the linear repression medel are generated by a seasonal autoregressive scheme the Cochrane Orcutt transformation estimator (COTE) is a well known alternative to Generalized Least Squares estimator (GLSE). In this paper it is analyzed in which situation the Ordinary Least Squares estimator (OLSE) is always better than COTE for positive autocorrelation in terms of efficiency which is here defined as the ratio of the total variances.

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Pitfalls of the Binomial Option Pricing Model (이항옵션가격 모형의 허점)

  • 김진욱
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2000.04a
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    • pp.314-317
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    • 2000
  • 금융파생상품인 옵션의 가치평가를 이해하는 데 널리 사용되는 이항분포모형은 다음과 같은 특징을 가지는 것으로 알려져 있다 첫째, 옵션의 가치는 주가의 상승 또는 하락할 확률과는 무관하게 결정된다. 둘째, 옵션의 가치는 투자자의 위험에 대한 태도와는 관계없이 결정된다. 이 논문에서는 옵션의 기초물인 주가가 한기간 후에 상승 또는 하락하는 기본모형에서 옵션의 가치평가가 주가의 변동 확률과 투자자의 위험에 대한 태도와 무관하지 않음을 예제를 통하여 밝히게 될 것이다.

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