• The Korean Journal of Applied Statistics
• /
• v.19 no.1
• /
• pp.97-110
• /
• 2006

Since it is well-established that even high quality data tend to contain outliers, one would expect fat? greater reliance on robust regression techniques than is actually observed. But most of all robust regression estimators suffers from the computational difficulties and the lower efficiency than the least squares under the normal error model. The weighted self-tuning estimator (WSTE) recently suggested by Lee (2004) has no more computational difficulty and it has the asymptotic normality and the high break-down point simultaneously. Although it has better properties than the other robust estimators, WSTE does not have full efficiency under the normal error model through the weighted least squares which is widely used. This paper introduces a new approach as called the reweighted WSTE (RWSTE), whose scale estimator is adaptively estimated by the self-tuning constant. A Monte Carlo study shows that new approach has better behavior than the general weighted least squares method under the normal model and the large data.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2011.05a
• /
• pp.41.2-41.2
• /
• 2011

Recently, scaling down of ULSI (Ultra Large Scale Integration) circuit of CMOS (Complementary Metal Oxide Semiconductor) based electronic devices become much faster speed and smaller size than ever before. However, very narrow interconnect line width causes some drawbacks. For example, deposition of conformal and thin barrier is not easy moreover metallization process needs deposition of diffusion barrier and glue layer. Therefore, there is not enough space for copper filling process. In order to overcome these negative effects, simple process of copper metallization is required. In this research, Cu-V thin alloy film was formed by using RF magnetron sputter deposition system. Cu-V alloy film was deposited on the plane $SiO_2$/Si bi-layer substrate with smooth and uniform surface. Cu-V film thickness was about 50 nm. Cu-V layer was deposited at RT, 100, 150, 200, and $250^{\circ}C$. XRD, AFM, Hall measurement system, and XPS were used to analyze Cu-V thin film. For the barrier formation, Cu-V film was annealed at 200, 300, 400, 500, and $600^{\circ}C$ (1 hour). As a result, V-based thin interlayer between Cu-V film and $SiO_2$ dielectric layer was formed by itself with annealing. Thin interlayer was confirmed by TEM (Transmission Electron Microscope) analysis. Barrier thermal stability was tested with I-V (for measuring leakage current) and XRD analysis after 300, 400, 500, 600, and $700^{\circ}C$ (12 hour) annealing. With this research, over $500^{\circ}C$ annealed barrier has large leakage current. However V-based diffusion barrier annealed at $400^{\circ}C$ has good thermal stability. Thus, thermal stability of vanadium-based thin interlayer as diffusion barrier is good for copper interconnection.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.3
• /
• pp.274-279
• /
• 2010

The present work is to analyze the longitudinal static stability and the drop trajectory of fighter aircraft's external fuel tank, of which horizontal fin is modified as the 20% scale down size compared with the original one. The analytical results to the pitching stability of external fuel tank using a thin airfoil's aerodynamic force data show the corresponding tendency to results of wind tunnel experiment. Results of trajectory simulation by the 6 degree of freedom equations of motion, comparing with drop trajectories of wind tunnel experiment, are shown that aircraft's attitude affects strongly on horizontal movement but not on the vertical movement. Those results give the reliability to aircraft safety when the external fuel tank with the 20% reduced horizontal fins is released from aircraft based on the flight manual.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.25 no.2
• /
• pp.73-81
• /
• 2019

Background: Patellofemoral pain is one of the common diseases of the musculoskeletal system. Many previous studies have recommended the application of exercise therapy to patellofemoral pain patients for treatment. The purpose of this study was to investigate effect of coordinative locomotor training (CLT) and sling exercise combined program on knee pain and functional movement in patellofemoral pain patient. Methods: In this study, single-subject design (A-B-A') was conducted for 6 weeks. A repeted-measure analysis was conducted to assess results of the anterior knee pain scale (AKPS), Clarke's test (CT), eccentric step down test (ESDT). During the intervention (B), the CLT and sling exercise combined program was conducted three times a week for 4 weeks. Results: From baseline period A to intervention period B, the AKPS, CT, ESDT were improved from 61 to 48 (27%), from 8.33 to 3 (64%), from 7.67 to 3,58 (53%). From baseline period A to baseline period A', the AKPS, CT, ESDT were improved from 70.67 to 48 (47%), from 0.67 to 3 (92%), from 1.33 to 3,58 (83%). Conclusion: Based on the results of this study, we recommend the application of CLT and sling exercise combined program to improve the pain and functional movement in patellofemoral pain patients.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.18
• /
• pp.8563-8566
• /
• 2016

Colorectal cancer is one of the most common lethal cancer types worldwide. In recent years, widespread and large-scale studies have been done on medicinal plants for anti-cancer effects, including Glycyrrhiza glabra. The aim of this study was to evaluate the effects of an ethanol extract Glycyrrhiza glabra on the expression of HSP90, growth and apoptosis in the HT-29 colon cancer cell line. HT-29 cells were treated with different concentrations of extract (50,100,150, and $200{\mu}g/ml$). For evaluation of cell proliferation and apoptosis, we used MTT assay and flow cytometry technique, respectively. RT-PCR was also carried out to evaluate the expression levels of HSP90 genes. Results showed that Glycyrrhiza glabra inhibited proliferation of the HT-29 cell line at a concentration of $200{\mu}g/ml$ and this was confirmed by the highest rate of cell death as measured by trypan blue and MTT assays. RT-PCR results showed down-regulation of HSP90 gene expression which implied an ability of Glycyrrhiza glabra to induce apoptosis in HT-29 cells and confirmed its anticancer property. Further studies are required to evaluate effects of the extract on other genes and also it is necessary to make an extensive in vivo biological evaluation and subsequently proceed with clinical evaluations.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.05a
• /
• pp.263-266
• /
• 2009

The mainly objectives of this study was a combustion dynamics and instability characteristics in a model gas turbine dump combustor which is the scale down of GE 7FA+e DLN 2.6 gas turbine combustor. Model gas turbine injector has 2-stage swirl vane and it’s reduced 1/3 size of the original one. The shape of plenum and combustor were designed for similar acoustic characteristics. Inlet air was preheated to $200{\sim}400^{\circ}C$. The flow velocity at mixing nozzle was 30 to 75 m/s and equivalent ratio was 0.4 to 1.2. The combustor length was varied for different acoustic characteristics to $375{\sim}700\;mm$. As the result, this research have been show the combustion instability was observed at lower equivalence ratios ($\Phi$ < $0.5{\sim}0.6$) and higher equivalent ratios ($\Phi$ > $1.1{\sim}1.2$).

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.11a
• /
• pp.231-235
• /
• 2009

The mainly objectives of this study was a combustion dynamics and instability characteristics in a model dump type combustor which is scale down of GE 7FA+e DLN 2.6 gas turbine combustor with running at Seo-Inchon combined cycle power plant. Model gas turbine injector has 2-stage swirl vane and it's reduced 1/3 size of the original one. The shape of plenum and combustor were designed for similar acoustic characteristics. As the result, this research have been shows the peak frequency of model combustor was changed quarter-wave mode to Helmholtz resonator mode in plenum and longitudinal mode in dump combustor at unstable flame conditions caused by the different of combustor temperature and fuel-air mixture distributions.

• Journal of Korean Foot and Ankle Society
• /
• v.14 no.2
• /
• pp.109-114
• /
• 2010

Purpose: The purpose of this study was to report the surgical outcome of reconstruction of neglected chronic Achilles tendon ruptures with various methods including Achilles tendon allograft. Materials and Methods: Between October 2003 and November 2008, 8 consecutive neglected chronic Achilles tendon ruptures with the defect gap of more than 4 cm underwent surgical reconstruction including V-Y advancement, gastrocnemius fascial turn-down flap, flexor hallucis longus transfer and Achilles tendon allograft. There were 7 males and 1 female who were evaluated at more than 18 months after surgery. At the time of followup, all patients were assessed with regard to postoperative complications, their self-reported level of satisfaction, the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot scale, 10 repetitive single heel rise, single leg hopping test, and ankle range of motion. Results: The AOFAS score increased from average 71.4 (50-87) to 96.4 (86-100). All patients were able to perform 10-repetitive single heel raise and single leg hopping at the latest follow up. No patient experienced wound complications and deep infection. Six patients were rated as 'excellent' and the other two as 'good'. Conclusion: Neglected chronic Achilles tendon ruptures could be successfully treated with careful selection of the reconstruction method according to the amount of defect gap. With an extensive defect, Achilles tendon allograft can be a good option when the reconstruction is not feasible otherwise.

• Journal of Periodontal and Implant Science
• /
• v.46 no.3
• /
• pp.207-217
• /
• 2016

Purpose: The aim of this study is to analyze and visualize the distribution of patients visiting the periodontology department at a dental college hospital, using a geographic information system (GIS) to utilize these data in patient care and treatment planning, which may help to assess the risk and prevent periodontal diseases. Methods: Basic patient information data were obtained from Dankook University Dental Hospital, including the unit number, gender, date of birth, and address, down to the dong (neighborhood) administrative district unit, of 306,656 patients who visited the hospital between 2007 and 2014. The data of only 26,457 patients who visited the periodontology department were included in this analysis. The patient distribution was visualized using GIS. Statistical analyses including multiple regression, logistic regression, and geographically weighted regression were performed using SAS 9.3 and ArcGIS 10.1. Five factors, namely proximity, accessibility, age, gender, and socioeconomic status, were investigated as the explanatory variables of the patient distribution. Results: The visualized patient data showed a nationwide scale of the patient distribution. The mean distance from each patient's regional center to the hospital was $30.94{\pm}29.62km$ and was inversely proportional to the number of patients from the respective regions. The distance from a regional center to the adjacent toll gate had various effects depending on the local distance from the hospital. The average age of the patients was $52.41{\pm}12.97years$. Further, a majority of regions showed a male dominance. Personal income had inconsistent results between analyses. Conclusions: The distribution of patients is significantly affected by the proximity, accessibility, age, gender and socioeconomic status of patients, and the patients visiting the periodontology department travelled farther distances than those visiting the other departments. The underlying reason for this needs to be analyzed further.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.7 no.6
• /
• pp.340-346
• /
• 2002

The purpose of the present study was to examine the efficacy and mechanism of the PAB (para-amino benzamidine) affinity column chromatography, Viresolve NFP virus filtration, pasteurization (60$\^{C}$ heat treatment for 10 h), and lyophilization steps employed in the manufacture of urokinase from human urine as regards the removal and/or inactivation of the hepatitis A virus (HAV). Samples from the relevant stages of the production process were spiked with HAV and subjected to scale-down processes mimicking the manufacture of urokinase Samples were collected at each step, immediately titrated using a 50% tissue culture infectious dose (TCID$\_$50/), and the virus reduction factors evaluated. PAB chromatography was found to be an effective step for removing HAV with a log reduction factor of 3.24. HAV infectivity was rarely detected in the urokinase fraction, while most of the HAV infectivity was recovered in the unbound and wash fractions. HAV was completely removed during the Viresolve NFP filtration with a log reduction factor of $\geq$ 4.60. Pasteurization was also found to be an effective step in inactivating HAV where the titers were reduced from an initial titer of 7.18 log$\_$10/ TCID$\_$50/ to undetectable levels within 10 h of treatment. The log reduction factor achieved during pasteurization was $\geq$ 4.76. Lyophilization revealed the lowest efficacy for inactivating HAV with a log reduction factor of 1.48. The cumulative log reduction factor was $\geq$ 14.08. Accordingly, these results indicate that the production process for urokinase exhibited a sufficient HAV reducing capacity to achieve a high margin of virus safety.