• Journal of Chest Surgery
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• v.28 no.1
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• pp.60-65
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• 1995

Congenital diverticula of the cardiac ventricle have been reported as arising either from the left ventricle or, rarely from both ventricles. A diverticulum arising from the right ventricle alone is very rare. Furthermore the diverticulum associated with double chambered right ventricle was extremely rare. We experienced a 62 years old female of double chambered right ventricle combined with congenital right ventricular true diverticulum. She had complained intermittent chest pain and mild dyspnea on exertion during 8 months. The chest X-ray and chest CT showed protruded abnormal density at anterolateral side of right ventricular outflow tract. Preoperative angiography demonstrated a double chambered right ventricle and a right ventricular diverticulum. In operative finding, there was found a anomalous muscle band, dividing the right ventricle into an inflow and outflow portion, and a 5x6cm sized right ventricular diverticulum arised from conus region with a stenotic orifice of 1.5cm in diameter. The diverticulum was open toward the infundibulum, and its orifice was approximately 1cm in diameter. On treatment, the diverticulum orifice was closed directly and the abnormal muscle band was resected in order to widen the right ventricular outflow tract. The postoperative result was satisfactory and good without specific complications.

• Bulletin of the Korean Mathematical Society
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• v.51 no.4
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• pp.1127-1133
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• 2014

Let S be a nonempty subset of a ring R. A map $f:R{\rightarrow}R$ is called strong commutativity preserving on S if [f(x), f(y)] = [x, y] for all $x,y{\in}S$, where the symbol [x, y] denotes xy - yx. Bell and Daif proved that if a derivation D of a semiprime ring R is strong commutativity preserving on a nonzero right ideal ${\rho}$ of R, then ${\rho}{\subseteq}Z$, the center of R. Also they proved that if an endomorphism T of a semiprime ring R is strong commutativity preserving on a nonzero two-sided ideal I of R and not identity on the ideal $I{\cup}T^{-1}(I)$, then R contains a nonzero central ideal. This short note shows that the conclusions of Bell and Daif are also true without the additivity of the derivation D and the endomorphism T.

• Kyungpook Mathematical Journal
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• v.19 no.2
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• pp.237-239
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• 1979

No matter how one chooses the major arcs in the decomposition of $[x_0,\;x_0+1]$ it is always true with regard to the union, m(n), of the corresponding minor arcs that the integal of $f^2(x,\;n)$ e(-nx) over m(n) is $O(nlog^{-1}n)$. Consequently, to establish a proof of the asymptotic formulation of Goldbach's conjecture one might be tempted to take this fact as a starting point and to then concentrate the attact on trying to obtain the requisite estimate on the integral of $f^2(x,\;n)$ e(-nx) over M(n), the union of a suitably chosen family of major arcs. In this paper I show that this approach is not possible.

• Animal cells and systems
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• v.11 no.2
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• pp.105-115
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• 2007

Two species of the genus Xysticus from Korea are revised with detailed illustrations, spination of each leg, trichobothrium patterns and SEM photographs. The female of X. concretus Utochkin, 1968 is described for the first time and Xysticus lepnevae Utochkin, 1968 from Korea represent the species' southernmost known records. The latter species is distinguished by its male palpal organs with hooked median apophysis, developed ventral tibial apophysis and expanded retrolateral tibial apopysis, two tegular sutures and by it epigynum with triangular atrium and large copulatory ducts circled, with broadly transparent membrane. Furthermore, the Xysticus spiders, previously misidentified in Korea as male of X. dichotomus Paik, 1973 and female of X. bifurcus Paik, 1973 are in fact the true X. concretus.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.10
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• pp.27-35
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• 1997

In this paper, we propose a new scheme for the generation of partial products for VLSI fast parallel multiplier. It adopts a new encoding method which halves the number of partial products using 2x2 submultipliers and rearrangement of primitive partial products. The true 4-input CSA can be achieved with appropriate rearrangement of primitive partial products out of 2x2 submultipliers using the newly proposed theorem on binary number system. A 16bit x 16bit multiplier has been desinged using the proposed method and simulated to prove that the method has comparable speed and area compared to booth's encoding method. Much smaller and faster multiplier could be obtained with far optimization. The proposed scheme can be easily extended to multipliers with inputs of higher resolutions.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.1075-1078
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• 1999

In this study, a new algorithm for canceling MRI artifacts through the translational motion of image plane is presented. Bloating is often makes problems in a clinical diagnosis. Assuming that the head moves up and down due to breathing, rigid translational motions in only y(phase encoding axis) direction is treated. First, we notice that the x directional motion corresponds to a shift of the x directional spectrum of the MRI signal, and the non zero area of the spectrum just corresponds to x axis projected area of the density function. So the motion is estimated by tracing the edges of the spectrum, and the x directional motion is canceled by shifting the spectrum in inverse direction. Next, the y directional motion is canceled using a new constraint, with which the motion component and the true image component can be separated. Finally, the effectiveness of this algorithm is shown by using a phantom with simulated motions.

• The korean journal of orthodontics
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• v.35 no.6 s.113
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• pp.420-432
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• 2005

Bolton analysis is widely used to predict tooth size discrepancy. but its accuracy has been challenged. The purpose of this study was to describe true anterior tooth size discrepancies among orthodontic patients and to evaluate the factors that affect true anterior tooth size discrepancies. The subjects consisted of 80 patients with varying malocclusions (Class I. Class II. Class III. and Class III surgery) who were treated orthodontically. Pre-treatment models. set-up models from post-treatment models. and lateral cephalometric radiographs were analyzed The results were as follows. The means. the standard deviations. and ranges of anterior Bolton ratio in the present study were somewhat higher than those of Bolton's samples and Korean normal samples. The number of patients showing maxillary deficiency was larger than that of patients showing maxillary excess in view of true anterior discrepancies. There was a significant difference between anterior Bolton discrepancy from pre-treatment models and true anterior discrepancy from set-up models (p < 0.05) There was no significant difference in true anterior discrepancies among malocclusion groups (p > 0.05). And there was also no significant difference between the male and female groups (p> 0.05). Overbite and the incisal edge thickness of maxillary anterior teeth have little relationship with true anterior discrepancies. Multiple regression analysis showed that true anterior discrepancy was mainly determined by anterior Bolton ratio, upper incisor to occlusal plane angle after treatment. interincisal angle after treatment. and upper right lateral incisor width.

• Bulletin of the Korean Mathematical Society
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• v.20 no.2
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• pp.95-97
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• 1983

In this paper, we show a necessary and sufficient condition for QHC spaces to be S-closed. T. Thomson introduced S-closed spaces in [2]. A topological space X is said to be S-closed if every semi-open cover of X admits a finite subfamily such that the closures of whose members cover the space, where a set A is semi-open if and only if there exists an open set U such that U.contnd.A.contnd.Cl U. A topological space X is quasi-H-closed (denote QHC) if every open cover has a finite subfamily whose closures cover the space. If a topological space X is Hausdorff and QHC, then X is H-closed. It is obvious that every S-closed space is QHC but the converse is not true [2]. In [1], Cameron proved that an extremally disconnected QHC space is S-closed. But S-closed spaces are not necessarily extremally disconnected. Therefore we want to find a necessary and sufficient condition for QHC spaces to be S-closed. A topological space X is said to be semi-locally S-closed if each point of X has a S-closed open neighborhood. Of course, a locally S-closed space is semi-locally S-closed.

• Journal of the Institute of Convergence Signal Processing
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• v.1 no.1
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• pp.49-57
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• 2000

In this study, a new algorithm for canceling a MRI artifact due to the translational motion In the image plane is described. Unlike the conventional iterative phase retrieval algorithm, in which there is no guarantee for the convergence, a direct method for estimating the motion is presented. In previous approaches, the motions in the x(read out) direction and the y(phase encoding) direction were estimated simultaneously. However, the feature of x and y directional motions are different from each other. By analyzing their features, each x and y directional motion is canceled by the different algorithms in two steps. First, it is noticed that the x directional motion corresponds to a shift of the x directional spectrum of the MRI signal, and the non-zero area of the spectrum just corresponds to the projected area of the density function on the x axis. So the motion is estimated by tracing the edges between non-zero area and zero area of the spectrum, and the x directional motion is canceled by shifting the spectrum in an reverse direction. Next, the y directional motion is canceled by using a new constraint condition, with which the motion component and the true image component can be separated. This algorithm is shown to be effective by using a phantom image with simulated motion.

• Journal of Chest Surgery
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• v.29 no.1
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• pp.52-58
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• 1996

Sixty six patients who were operated as lung cancer during the period from Mar. 1991 to Sep. 1993 at the department of Thoracic and cardiovascular surgery, were reviewed retrospectively and the accuracy of regional lymph node in preoperative CT were compared with histopathologlc report obtained from operation. The age ranged from 30 to 72 years old (mean age : 56.5), and 51 patients were male and 15 patients were female. The author analysed the true positive, true negative, false positive and false negative and sensitivity, specificity, positive predictive index, negative predictive index and accuracy of each nodes. The result is that there were differences between seven nodal groups in specificity, sensitivity, positive predictive Index, negative predictive index and accuracy. The range of each nodal group is from 81.7 to 98.3% The nodes of the most poor accuracy are aortopulmonary area and hilar area.