• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5C
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• pp.692-699
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• 2004

In this paper we studied an implementation of QR decomposition-based RLS algorithm using modified Givens rotation method. Givens rotation can be obtained with a sequence of the CORDIC operations. In order to reduce the computing time of QR decomposition we restricted the number of iterations of the CORDIC operation per a Givens rotation and used double-rotation method to remove the square-root in the scaling factor.

• The Korean Journal of Applied Statistics
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• v.17 no.1
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• pp.61-73
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• 2004

Rotation sampling designs may be classified into two categories. The first type uses the same sample unit for the entire life of the survey. The second type uses the sample unit only for a fixed number of times. In both type of designs, the entire sample is partitioned into a finite number(=G) of rotation groups. This paper is generalization of the first type designs. Since the generalized design can be identified by only G rotation groups and recall level 1, we denote this rotation system as l/G rotation design. Under l/G rotation design, variance and mean squared error (MSE) of generalized composite estimator are derived, incorporating two type of biases and exponentially decaying correlation pattern. Compromising MSE's of some selected l/G designs, we investigate design efficiency, design gap effect, ans the effects of correlation and bias.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.2
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• pp.14-20
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• 2011

In mobile ad hoc networks where the communication nodes are moving around, one may perform dynamic routing that can increase the total communication throughput of the network, by determining the ranks of pairs of nodes according to their communication throughput. The balanced Howell rotation is a tournament design scheme for bridge games. This paper explains that the balanced Howell rotation can be applied to enhance the overall communication throughput of mobile ad hoc networks, and proposes and proves the condition under which the balanced Howell rotations may exist.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.3
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• pp.279-284
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• 2014

PURPOSE: This study intended to verify whether there was actual correlation between weight-bearing asymmetry and a limitation in hip joint rotation range in patients with low back pain. METHODS: Thirty five low back pain patients voluntarily participated this study. For each participant, hip joint medial rotation symmetry rate and the weight-bearing symmetry rate were calculated. The correlation between the two variables was investigated. RESULTS: A decrease in the left hip joint medial rotation range of motion (ROM) was observed more often than a reduction in the right hip joint medial rotation ROM. However, similar number between right and left side was observed in ground reaction force more weighted. The coefficient between the passive hip joint medial rotation symmetry rate and the weight loading symmetry ratio was -0.19 (p < 0.05). CONCLUSION: The present study demonstrated a weak correlation between the hip joint medial rotation ROM and the weight distribution of both feet. Such result suggests that careful evaluation by separating each element is needed in treating patients with low back pain. Future research should take into account asymmetric alignment and abnormal movement in different joints of the body as well as asymmetry in the bilateral hip joint rotation and the unilateral weight supporting posture.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.323-326
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• 2006

Numerical solutions for spin-up problem of a thermally stratified fluid in a cylinder with an insulating sidewall and time-dependent rotation rate are presented. Detailed results are given for aspect ratio of O(1), fixed Ekman number $10-^{4}$, Rossby number 0.05 and Prandtl number O(1). Angular velocity of a cylinder wall changes with following formula, $\Omega_f=\Omega_i+\Delta\Omega[1-\exp(-t/t_c)]$. Here, this $t_c$, value, which is very significant in present study, represents that how fast/slow the angular velocity of the cylinder wall reaches final angular velocity. The normalized azimuthal velocity and meridional flow plots for several tc value which cover ranges of the stratification parameter S(1 ~ 10) are presented. The role of viscous-diffusion and Coriolis term in present study is examined by diagnostic analysis of the azimuthal velocity equation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.7
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• pp.957-966
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• 2000

The effect of rotation on the discharge coefficient of orifices with various length-to-diameter ratios and two different inlet corner radii was studied. Length-to-diameter ratios of the orifices range from 0.2 to 10, while the inlet shapes are square edged, or round edges of radius-to-diameter ratio of 0.5. From the experiment, we found that rotational discharge coefficient and Rotation number, when based on ideal exit velocity of the orifice considering momentum transfer from the rotor, describe the effect of rotation very well. In this study, the discharge coefficients of rotating orifices are shown to behave similar to those of the well-known non-rotating orifices. For both rotating and non-rotating orifices, the discharge coefficients increase with the length-to-diameter ratio until a maximum is reached. The flow reattachments in the relatively short orifices are responsible for the increase. The coefficient then decreases with the length-to-diameter ratio due to the friction loss along the orifice bore. The length-to-diameter ratio that yields maximum discharge coefficient, however, increases with the Rotation number because the increased flow-approaching angle requires larger length-to-diameter ratio for complete reattachment. The length-to-diameter ratio for complete reattachment is shorter for round edged orifices than that of square edged orifices by about a unit length-to-diameter ratio.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.10
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• pp.949-954
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• 2010

Computing the rotation-invariant distance between image time-series is a time-consuming process that incurs a lot of Euclidean distances for all possible rotations. In this paper we propose an innovative solution that significantly reduces the number of Euclidean distances using the triangular inequality. To this end, we first present the notion of self rotation distance and show that, by using the self rotation distance with the triangular inequality, we can prune many unnecessary distance computations. We next present that only one self-rotation is enough for all self-rotation distances required. Experimental results show that our self rotation distance-based methods outperform the existing methods by up to an order of magnitude.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.39-44
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• 2001

The thermocapillary flow in a differentially heated cylindrical liquid bridge under steady rotation of the hot disk is considered in the limit of zero capillary number. Steady flow states and their three-dimensional stability are calculated numerically. A linear stability analysis reveals that the most dangerous perturbations are oscillatory with azimuthal wavenumber m=1 or m=2 depending on the parameters.

• Journal of the Korean Data and Information Science Society
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• v.15 no.2
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• pp.297-306
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• 2004

It is usual that multivariate data analysis produces related (small number of) artificial variates for data reduction. Among them, refer to MDS(multidimensional scaling), MDPREF(multidimensional preference analysis), CDA(canonical discriminant analysis), CCA(canonical correlation analysis) and FA(factor analysis). Varimax rotation of artificial variables which is originally invented in FA for easy interpretations is applied to diverse multivariate techniques mentioned above. Real data analysisis is performed in order to manifest that rotation improves interpretations of artificial variables.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.4
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• pp.115-122
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• 1994

Roberige had proposed a method of linear approximation using strips. This method is known to be fast relatively, and the distance between the given curve and calculated straight line is not greater than an allowable error. But this method generates many break points. Later, Leng and Yang proposed the dynamic strip algorithm with the rotation of strips which reduced the number of greak points at the sacrifice of the speed. The method using the seperate rotation of two strip lines proposed in this paper is faster than Leng and Yang's but generates almost the same number of break points as Leng and Yang's.