• Journal of Astronomy and Space Sciences
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• v.15 no.1
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• pp.175-182
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• 1998

Any classification process using SAR images presupposes the reduction of multiplicative speckle noise, since the variations caused by speckle make it extremely difficult to distinguish between neighboring classes within the feature space. Therefore, several adaptive filter algorithms have been developed in order to distinguish between them. These algorithms aim at the preservation of edges and single scattering peaks, and smooths homogeneous areas as much as possible. This task is rendered more difficult by the multiplicative nature of the speckle noise the signal variation depends on the signal itself. In this paper, LEE(Lee 1908) and R-LEE(Lee 1981) filters using local statistics, local mean and variance, are applied to RADARSAT SAR images. Also, a new method of speckle filtering, EPOS(Edge Preserving Optimal Speckle)(Hagg & Sties 1994) filter based on the statistical properties of speckle noise is described and applied. And then, the results of filtering SAR images with LEE, R-LEE and EPOS filters are compared with mean and median filters.

• The Korean Journal of Applied Statistics
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• v.13 no.2
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• pp.407-414
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• 2000

Carroll and Ruppert(1988) analyzed the esterase assay data with regression model based on quasi-likelihood. Jung and Lee(1997) introduced a goodness-of-fit test for testing the adequacy of the quasi-likelihood and claimed that there is no gross inadequacy with the model because their test was not rejected. However, Lee and Xelder(199S)'s residual plots revealed that the model did not sufficiently reflect the increase of the variance with that of the mean. In this paper, we re-analyze the esterase assay data with the joint modelling of mean and dispersion in Lee and l\elder(1998) and evaluate the validity of the fitted model by applying the residual plots. And it is illustrated that Lee and Nelder(199S)'s restricted likelihood is more efficient in goodness-of-fit test for the dispersion model.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.3
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• pp.245-251
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• 2014

As delineating market areas of retail businesses has become an interesting topic in marketing field, Lee and Lee recently suggested a noteworthy method, which applied the hydrological analysis of geographical information system (GIS), based on Christaller's central place theory. They used a digital elevation model (DEM) which inverted the kernel density of retail businesses, which was measured by using bandwidths of pre-determined 500, 1000 and 5000 m, respectively. In fact, their method is not a fully data-based approach in that they used pre-determined kernel bandwidths, however, this paper has been planned to improve Lee and Lee's method by using a kind of data-based approach of the L-index that describes clustering level of point feature distribution. The case study is implemented to automobile-related retail businesses in Seoul, Korea with selected Kernel bandwidths, 1211.5, 2120.2 and 7067.2 m from L-index analysis. Subsequently, the kernel density is measured, the density DEM is created by inverting it, and boundaries of market areas are extracted. Following the study, analysis results are summarized as follows. Firstly, the L-index can be a useful tool to complement the Lee and Lee's market area analysis method. At next, the kernel bandwidths, pre-determined by Lee and Lee, cannot be uniformly applied to all kinds of retail businesses. Lastly, the L-index method can be useful for analyzing the space structure of market areas of retail businesses, based on Christaller's central place theory.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.2
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• pp.285-292
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• 2009

In 2005, Lee and Chen suggested an enhanced one-time password authentication scheme which can prevent the stolen verifier attack that the Yeh-Shen-Whang's scheme has. The Lee-Chen's scheme addresses the stolen verifier attack by deriving each user's pre-shared secret SEED from the server secret. However, we investigated the weakness of the Lee-Chen's scheme and found out that it was suffering from the off-line dictionary attack on the server secret. We demonstrated that the off-line dictionary attack on the server secret can be easily tackled with only the help of the Hardware Security Modules (HSM). Moreover, we improved the scheme not to be weak to the denial of service attack and allow compromise of the past session keys even though the current password is stolen. Through the comparison between the Lee-Chen's scheme and the proposed one, we showed that the proposed one is stronger than other.

• Physical Therapy Korea
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• v.26 no.4
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• pp.10-19
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• 2019

Background: In patients with lumbar spinal stenosis (LSS), lumbar flexion exercise (LFE) is considered a standard therapeutic exercise that widens the space between the spinal canal and intervertebral foramen. However, some researchers have reported that lumbar extension exercise (LEE) may improve lumbar pain and functional ability in patients with LSS. Although exercise intervention methods for patients with LSS have been widely applied in clinical settings, few studies have conducted comparative analysis of these exercise methods. Objects: This study aimed to compare the effects of LFE, LEE, and lumbar flexion combined with lumbar flexion-extension exercise (LFEE) on pain, range of motion (ROM), pelvic tilt angle, and functional gait ability in patients with LSS. Methods: A total of 30 patients with LSS, LFE (n1=10), LEE (n2=10), and LFEE (n3=10) were assigned to each of the three exercise groups. The numerical pain rating scale (NPRS), modified-modified schober test (MMST)-flexion, MMST-extension, pelvic tilt inclinometer, and 6-minute walking test (6MWT) were measured. Results: After the intervention, statistically significant differences were observed in the NPRS (p=.043), MMST-flexion (p<.001), MMST-extension (p<.001), and 6MWT (p=.005) between groups. According to the post hoc test, the NPRS was statistically significant difference between the LFEE and LEE groups (p=.034). The MMST-flexion was statistically significantly different between the LFE and LEE (p=.000), LFE and LFEE (p=.001), and LEE and LFEE (p=.001) groups. The MMST-extension was statistically significantly different between the LFE and LEE (p<.001), LFE and LFEE (p=.002), and LEE and LFEE (p=.008) groups. The 6MWT was statistically significantly different between the LFE and LFEE (p=.042) and the LEE and LFEE (p=.004) groups. Conclusion: This study suggested that LFEE was the most effective exercise for pain and functional gait ability in patients with LSS, LFE was the most effective exercise for lumbar flexion ROM, and LEE was the most effective exercise for lumbar extension ROM.

• The Bulletin of The Korean Astronomical Society
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• v.33 no.1
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• pp.43.2-43.2
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• 2008

• Bulletin of the Korean Space Science Society
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• 2008.04a
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• pp.27.1-27.1
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• 2008

• Journal of Applied Biological Chemistry
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• v.52 no.2
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• pp.88-91
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• 2009

• Journal of Environmental Science International
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• v.16 no.5
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• pp.541-548
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• 2007

A three-dimensional linear model and the Advanced Regional Prediction System (ARPS) were used to simulate parabola-shaped disturbances and clouds in the lee of a bell-shaped mountain. The ARPS model was compared in the x-y plane against the linear model's analytic solution. Under similar conditions with the linear theory, the ARPS produced well-developed parabola-shaped mountain disturbances and confirmed the features are accounted for in the linear regime. A parabola-shaped cloud in the lee of an isolated bell-shaped mountain was successfully simulated in the ARPS after 6 hours of integration time with the prescribed initial and boundary conditions, as well as a microphysical scheme.

• Journal of the Korean Chemical Society
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• v.50 no.3
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• pp.263-268
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• 2006