• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.4
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• pp.1194-1201
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• 1996

For the case of creep-fatigue interaction, the damage zone developed in front of the growing crack-tip during creep regime is important because it can affect the damage mechanism to be occured by the following fatigue load. These are studied in theis paper through proper consideration of the cavitiy-size dependent sintering stress which is approximated by polynomials. It is shown that the inclination of reversed damage zone size with respect to the applied load parameter can be explained by considering realistic sintering stress distribution. However, the resultant stress field has $r^{1/2+\theta}$ singularity, regardliss of the profile of variable sintering stress, which is the same to that case solved for constant sintering stress.

• Structural Engineering and Mechanics
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• v.23 no.5
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• pp.563-577
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• 2006

This study involves a series of experiments on the buckling strength of eccentrically compressed cold-formed stainless steel square hollow-section columns. The principal parameters in this study are slenderness ratios ($L_k/r$ = 30, 50, 70) and magnitude of eccentricity e (0, 25, 50, 75, 100 mm) on the symmetrical end-moment. The objectives of this paper are to obtain the buckling loads by conducting a series of experiments and to compare the behavior of the eccentrically compressed cold-formed stainless steel square hollow-section columns with the results of the analysis. The ultimate buckling strength of the square-section members were determined with the use of a numerical method in accordance with the bending moment-axial force (M-P) interaction curves. The behavior of each specimen was displayed in the form of a moment-radian (M-${\theta}$) relationship. The numerically obtained ultimate-buckling interaction curves of the beam columns coincided with the results of the experiments.

• Journal of Information Processing Systems
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• v.13 no.1
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• pp.174-183
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• 2017

In this paper, we propose a novel feature for recognizing handwritten Odia numerals. By using polygonal approximation, each numeral is segmented into segments of equal pixel counts where the centroid of the character is kept as the origin. Three primitive contour features namely, distance (l), angle (${\theta}$), and arc-tochord ratio (r), are extracted from these segments. These features are used in a neural classifier so that the numerals are recognized. Other existing features are also considered for being recognized in the neural classifier, in order to perform a comparative analysis. We carried out a simulation on a large data set and conducted a comparative analysis with other features with respect to recognition accuracy and time requirements. Furthermore, we also applied the feature to the numeral recognition of two other languages-Bangla and English. In general, we observed that our proposed contour features outperform other schemes.

• Proceedings of the Korea Water Resources Association Conference
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• 1984.07a
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• pp.89-98
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• 1984

우리나라의 월강우량 기록은 풍부하나 월유출량 기록은 희박하여, 월유출량 시계열의 모형식을 개발하고저 하여 월강우량 기록만으로 하천유량의 정확한 파악을 할 수 있도록 한다. 이 연구는 월강우와 유출량의 시계열에 의한 추계학적 이론에 의거한 복스와 젠킨스의 대체함수(Transfer function model)와 아리마(ARIMA)의 잔차모양을 합한 형이다. 이 선형 추계학적 차분 시계열식 모형은 공본산(coveriance) 을 갖는다는 가정에서 강우량과 유출량의 변화에 따라서 식의 구조가 유도되며 정확하게 잘 적용이 된다. 본 식의 최적모형은 일반식으로 아래와 같이 얻어진다. $ Y$:월유출량, X$:월강우량, C$:유출물, $: 대체변수, a$:백색잡음(white noise), $\theta$(B) 및 (B):MA(Moving average)와 AR(autoregressive)조작, 이번 연구 결과 섬진강 하천의 대체조작(Transfer operator)은 잔차승(Sum of residual) R$0.9로 높은 정도의 수치를 나타내는 것으로 보인다.

• Communications of the Korean Mathematical Society
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• v.31 no.4
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• pp.857-868
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• 2016

Let (X, ${\mu}$) be a generalized topological space (GTS) and $\mathcal{H}$ be a hereditary class on X due to $Cs{\acute{a}}sz{\acute{a}}r$ [8]. In this paper, we define an operator $()^{\circ}:\mathcal{P}(X){\rightarrow}\mathcal{P}(X)$. By setting $c^{\circ}(A)=A{\cup}A^{\circ}$ for every subset A of X, we define the family ${\mu}^{\circ}=\{M{\subseteq}X:X-M=c^{\circ}(X-M)\}$ and show that ${\mu}^{\circ}$ is a GT on X such that ${\mu}({\theta}){\subseteq}{\mu}^{\circ}{\subseteq}{\mu}^*$, where ${\mu}^*$ is a GT in [8]. Moreover, we define and investigate ${\mu}^{\circ}$-codense and strongly ${\mu}^{\circ}$-codense hereditary classes.

• Bulletin of the Korean Chemical Society
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• v.6 no.1
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• pp.7-11
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• 1985

The crystal structure of phlorizin, a ${\beta}$ -D-glucopyranoside of a flavonoid dihydrochalcone phloretin, has been determined by single crystal diffraction methods using diffractometer data obtained by the ${\omega}-2{\theta}$ scan technique with Cu $K{\alpha}$ radiation from a crystal with space group symmetry $P2_12_12_1$ and unit cell parameters a = 4.9094 (2), b = 19.109 (1), c = 23.275 (4) $\AA$. The structure was solved by direct methods and refined by full-matrix least-squares to a final R = 0.047 for the 1697 observed reflections. The dihydrochalcone moiety is flat and fully extended. The glucose ring has the $^4C_1$ chair conformation and the conformation of the primary alcohol group is gauche-gauche. The crystal packing is dominated by an extensive hydrogen bonding pattern. There are one strong and two weak intramolecular hydrogen bonds in the phlorizin molecule.

• Bulletin of the Korean Chemical Society
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• v.4 no.3
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• pp.123-127
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• 1983

The crystal structure of metoclopramide, $C_14H_22ClN_3O_2$, has been determined by X-ray diffraction techniques using diffractometer data obtained by the ${\omega}-2{\theta}$ scan technique with Mo $K\alpha$ radiation from a crystal with space group symmetry $P{\overline{1}}$ and unit cell parameters a = 7.500(1), b = 8.707(2), c = 13.292(2) ${\AA}$; ${\alpha}$ = 101.70(2), ${\beta}$ = 81.20(2), and ${\gamma}$ = $114.90(l)^{\circ}$. The sructure was solved by direct methods and refined by full-matrix least-squares to a final R = 0.055 for the 1524 observed reflections. The bent overall-conformation of the molecule seems to be determined mainly by the bifurcated intramolecular hydrogen bond from the amide nitrogen atom to the methoxy oxygen and the amine nitrogen atoms. The crystal packing consists of the hydrogen bonds, ${\pi}-{\pi}$ interaction and hydrophobic interaction.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.536-542
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• 2008

The rocket technology has the best reliability and the high acceleration performance currently. In addition, next generation propulsion system is acquired to low cost and high payload percentage at that same time. This work is to improve the performance of Diskshaped MHD accelerator which is expected as the one of the solution. In this study we have been focusing on the swirl vane. It is so important to know that how the swirl vane contribute the plasma and its performance. As results, the gas velocities of r-component with inlet swirl were increased about over 3000m/s at the channel exit. And then static gas pressure were also reduced, we found that the case with inlet swirl gives the good influence to the acceleration performance. And the difference of the acceleration by positive and negative inlet swirl is that gas velocity of $\theta$-component may operate to the electric field.

• Bulletin of the Korean Chemical Society
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• v.6 no.4
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• pp.222-224
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• 1985

The crystal structure of sulindac, $C_{20}H_{17}Fo_3S$, one of the nonsteroid antiinflammatory agents, has been determined by the X-ray diffraction techniques using diffractometer data obtained by the $\varpi-2{\theta}$ scan technique with Cu $$K_{\alpha}$$ radiation from a crystal with space group symmetry Pbca and unit cell parameters a = 8.166(1), b = 18.291(8), c = 23.245(10) ${\AA}.$ The structure was solved by direct methods and refined by full-matrix least-squares to a final R = 0.11 for the 1153 observed reflections. The carboxyl group is nearly perpendicular to the indenyl ring as observed in indomethacin. The dihedral angle between the indenyl and phenyl rings is $35^{\circ}while$ the corresponding angle in indomethacin is $67^{\circ}.$ Crystal packing consists of a hydrogen bond and partial ring stacking between the indenyl rings.

• Bulletin of the Korean Chemical Society
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• v.5 no.4
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• pp.158-162
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• 1984

The crystal structure of chloramphenicol base, $C_9H_{l2}N_2O_4$, the deacylated base of antibiotic chloramphenicol, has been determined by X-ray diffraction techniques using diffractometer data obtained by the ${\omega}-2{\theta}$ scan technique with CuK${\alpha}$ radiation from a crystal with space group symmetry $P2_12_12_1$ and unit cell parameters a = 22.322(6), b = 7.535(6), c = 5.781(5) ${\AA}$. The structure was solved by direct methods and refined by full-matrix least-squares to a final R = 0.051 for the 573 observed reflections. The overall conformation of the base is quite different from those of the chloramphenicol congeners which are similar despite the presence of many rotatable single bonds. The propane chain in the base is bent with respect to the phenyl ring, while it is extended in the chloramphenicol congeners. There is no intramolecular hydrogen bond between the hydroxyl groups of the propanediol moiety. All of the molecules in the crystal lattice are connected by a three-dimensional hydrogen bonding network.