• Korean Journal of Radiology
• /
• v.22 no.11
• /
• pp.1809-1821
• /
• 2021

Ovarian cystadenofibroma is a benign ovarian tumor that is characterized by a consistent percentage of masses, which remain indeterminate in ultrasonography and require magnetic resonance (MR) investigation; they may mimic borderline or malignant lesions. Three main morphologic patterns, resembling different ovarian neoplasms, can be identified in cystadenofibromas: multilocular solid lesions, unilocular cystic lesions with parietal thickening, and purely cystic masses. However, a cystoadenofibroma has typical features, such as T2-weighted hypointensity associated with no restrictions in diffusion-weighted imaging (the so-called "dark-dark appearance") and progressive post-contrast enhancement (type I perfusion curve). The purpose of this study was to review the features of ovarian cystadenofibromas in MR imaging and to suggest pearls and pitfalls regarding their correct diagnosis.

• Journal of the Korean Society of Radiology
• /
• v.82 no.5
• /
• pp.1140-1162
• /
• 2021

Tearing of the acetabular labrum is a common cause of chronic hip pain. MR arthrography (MRA) of the hip is the imaging procedure of choice for the evaluation of acetabular labrum. Familiarity with the various imaging findings of MRA of the hip allows recognition of normal variants and differentiation from true pathologic conditions. This article comprehensively reviews the technical aspects and interpretation of MRA of the hip. The appearances of normal and abnormal labra in MRA are discussed. Potential pitfalls in labral tear interpretation, such as sulci around the hip, normal variants of the labrum and plicae, and osseocartilaginous and soft tissue lesions identified on MRA of the hip are also described.

• Journal of the Korean Society of Radiology
• /
• v.85 no.1
• /
• pp.124-137
• /
• 2024

Malrotation and midgut volvulus are surgical emergencies that commonly occur within the first month of life. The classic symptom is acute bilious vomiting, while nonspecific symptoms such as recurrent abdominal pain may be present in older children. Malrotation can be associated with duodenal obstruction caused by an abnormal peritoneal fibrous band or congenital anomalies, such as an annular pancreas or a preduodenal portal vein. Volvulus can lead to bowel ischemia and a life-threatening condition, thus prompt and accurate diagnosis is crucial. Diagnosis can be made through upper gastrointestinal series, ultrasonography, and CT, with ultrasonography being preferred as a screening tool due to its rapid and accurate diagnosis, without radiation exposure, in children. This pictorial essay discusses the key imaging findings and diagnostic approaches for malrotation and midgut volvulus, as well as diagnostic pitfalls based on actual cases.

• Journal of applied mathematics & informatics
• /
• v.30 no.3_4
• /
• pp.395-411
• /
• 2012

Several methods with order higher than that of Newton methods which are of order 2 have been reported in literature for solving nonlinear equations. The focus of most of these methods was to economize on/minimize the number of function evaluations per iterations. We have demonstrated here that there are several computational pit-falls, such as the violation of fixed-point theorem, that one could encounter while using these methods. Further it was also shown that the overall computational complexity could be more in these high-order methods than that in the second-order Newton method.

• Journal of the Ergonomics Society of Korea
• /
• v.35 no.4
• /
• pp.247-261
• /
• 2016

Objective:The aim of this paper is to discuss the nuclear safety culture in Korea. Background: Recently, Korean nuclear field has met a strong anti-nuclear trend after a few happenings, as well as Fukushima accident, which are turned out to be caused by organizational pitfalls and safety culture defects in general. Method: We review the concepts and constructs of safety culture based on the brief history of the nuclear safety culture that IAEA mainly raised after the Chernobyl accident in 1986. Additionally, we give a comparative discussion on the approach to the safety culture with U.S. Results: Finally, we discuss the three technical domains and propose six selected domestic issues related to the nuclear safety culture for coping with the demanding requests on nuclear safety in Korea. Conclusion and Application: We suggest several recommendations and a research direction in the form of a re-start line for the nuclear safety culture in Korea.

• East Asian Journal of Business Economics (EAJBE)
• /
• v.2 no.4
• /
• pp.9-25
• /
• 2014

The successful implementation of various Enterprise Resource Planning (ERP) systems has provoked considerable interest in this subject over the last few years. The senior management, especially in large corporations have been attracted to look at new information technology and how to leverage it for corporate survival and to gain competitive advantage in volatile business environment. Although there is no shortage of positive reports on the success of ERP installations, many companies have invested millions of dollars in this direction with little to show for its success. Since many of the ERP failures today can be attributed to inadequate planning and poor execution in the implementation and closure of projects. The aim of this article is to offer some solutions to avert potential pitfalls in ERP implementation.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.34 no.3
• /
• pp.200-204
• /
• 2012

In the repair of unilateral complete cleft lip, the most popular method is the rotation-advancement by Millard. Despite advantages of Millard repair, a few pitfalls exist. Above all, some of the scars, at the height of the cleft side philtral ridge, cross the Langer's line. Further, in the repair of complete cleft lip, small triangular lateral lip flap is often added in the base of an advancement flap to level the Cupid's bow. Moreover, preservation of the advancement flap has some negative effects on a primary nasal repair. As a result, the shape of philtrum is somewhat unnatural. Therefore, I applied the extended Mohler repair in the six cases of complete wide cleft lip to get a more esthetic scar. As a result, more natural, straight philtral ridge was obtained, without adding small triangular flap in the base of the advancement flap.

• Journal of the Korean Data and Information Science Society
• /
• v.17 no.2
• /
• pp.661-668
• /
• 2006

There have been some controversies on the use of the coefficient of determination for linear no-intercept model. One definition of the coefficient of determination, $R^2={\sum}\;{\widehat{y^2}}\;/\;{\sum}\;y^2$, is being widely accepted only for linear no-intercept models though Kvalseth (1985) demonstrated some possible pitfalls in using such $R^2$. Main objective of this note is to report that $R^2$ is not a desirable measure of fit for the no-intercept linear model. In fact it is found that mean square error(MSE) could replace $R^2$ efficiently in most cases where selection of no-intercept model is at issue.

• 한국데이터정보과학회:학술대회논문집
• /
• 2005.04a
• /
• pp.145-154
• /
• 2005

There have been some controversies on the use of the coefficient of determination for linear no-intercept model. One definition of the coefficient of determination, $R^2=\sum\;{y}{^{\hat{2}}/\sum\;{y^2}$, is being widely accepted only for linear no-intercept models though Kvalseth(1985) demonstrated some possible pitfalls in using such $R^2$. Main objective of this article is to provide a cautionary notice for use of the $R^2$ by pointing out its tricky aspects by means of empirical simulations.

• Annals of Clinical Neurophysiology
• /
• v.1 no.1
• /
• pp.60-63
• /
• 1999

Transcranial Doppler(TCD) is an important diagnostic tool for evaluating the patients with stroke. It has some advantages and unique role when compared with other neuroimaging modalities. Recent development of transcranial color-coded Doppler(TCD) improves the limitation and pitfalls of TCD. The current indications of TCD are as follows: 1. Screening and evaluation of the intracranial major vessels 2. early detection and follow-up of vasospasm due to SAH 3. emboli detection (high-imtensity transient signals, HITs) 4. dignosis and follow-up of subclavian steal 5. evaluation of intracranial collaterals when the extracranial ICA has severe stenosis or occlusion 6. evaluation of cerebral perfusion pressure (intracranial pressure) 7. evaluation of arteriovenous malformation 8. diagnosis and follow-up of arterial dissenction 9. diagnosis and follow-up of venous sinus thrombosis (experimental).