• Journal of the Korean Statistical Society
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• v.34 no.3
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• pp.209-218
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• 2005

In response surfaces analysis, we often proceed by supposing that, over a limited region of factor space, a polynomial of only first or second degree might adequately approximate the true function. To find the best subset model, all possible quadratic regressions for response surfaces can be very valuable to get optimum solutions under some reasonable experimentations. However, there is a very hard computational burden to get all possible quadratic regressions. In practice, it is sufficient to consider only hierarchical models. In this paper, we propose an algorithm to get all possible hierarchical quadratic regressions for fitting response surfaces.

• Journal of Korean Society for Quality Management
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• v.40 no.4
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• pp.481-496
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• 2012

Purpose: This paper aims at improving inefficiency of an existing posterior preference articulation method proposed for dual response surface optimization. The method generates a set of non-dominated solutions and then allows a decision maker (DM) to select the best solution among them through an interval selection strategy. Methods: This paper proposes an iterative posterior preference articulation method, which repeatedly generates the predetermined number of non-dominated solutions in an interval which becomes gradually narrower over rounds. Results: The existing method generates a good number of non-dominated solutions not used in the DM's selection process, while the proposed method generates the minimal number of non-dominated solutions necessitated in the selection process. Conclusion: The proposed method enables a satisfactory compromise solution to be achieved with minimal cognitive burden of the DM as well as with light computation load in generating non-dominated solutions.

• Journal of Korea Planning Association
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• v.54 no.4
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• pp.71-78
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• 2019

Due to the rapid pace of low fertility and aging of Korea, population decline is rapidly progressing in the outskirts of the province and county. Demand for public transport is decreasing due to suburban population declines, while local government funding for maintenance of the bus system is expected to increase gradually. The government and municipalities are promoting the introduction of Demand Responsive Transport (DRT) in order to reduce the burden of financial support for buses while enhancing mobility of the residents in vulnerable areas. However, most DRTs in Korea have been operated mainly in the areas that are not provided with public transportation services. Although DRT is able to reduce the financial burden of local governments, it is not easy to be introduced because of the objection of the existing bus users. In this study, 11 out of 61 towns with poor public transportation services in Gyeongsangnam-Do were selected for the introduction of DRT to replace bus services by using village characteristics. The results of this study are expected to be used as a basis for decision making to use DRT instead of bus service for the burden of bus financing for local governments.

• Research in Mathematical Education
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• v.25 no.4
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• pp.267-284
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• 2022

In response to the current educational situation of students' heavy workload, the author constructs the precision-targeted classroom based on Precision Teaching (PT), Network Pharmacology, and Treatment Based on Syndrome Differentiation. The precision-targeted classroom can solve the current problems of PT and the phenomenon of the heavy academic burden on students, achieve the reduction of the burden and increase the efficiency of education. The precision-targeted classroom includes five key points: targeted goals, childlike thinking, precise intervention, intelligent homework, and stereoscopic evaluation, and the implementation process of the precision-targeted classroom is built from three aspects: before, during and after class. In addition, the author applied it to the actual mathematics classroom to test its teaching effect, and the experimental results showed that: the precision-targeted classroom significantly improved students' academic performance and thinking level; considerably improved students' classroom learning status, and facilitated teaching personalization and realized homework quantity control and quality improvement.

• Journal of Korean Association for Spatial Structures
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• v.18 no.4
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• pp.41-48
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• 2018

Recently, the concept of an outrigger damper system with a damper added to the existing outrigger system has been developed and applied for dynamic response control of high-rise buildings. However, the study on the structural characteristics and design method of Outrigger damper system is in the early stages. In this study, a 50 story high - rise building was designed and an outrigger damper system with viscoelastic damper was applied for wind response control. The time history analysis was performed by using the kaimal spectrum to create an artificial wind load for a total of 1,000 seconds at 0.1 second intervals. Analysis of the top horizontal maximum displacement response and acceleration response shows that outrigger damper systems are up to 28.33% and 49.26% more effective than conventional outrigger systems, respectively. Also, it is confirmed that the increase of damping ratio of dampers is effective for dynamic response control. However, since increasing the damping capacity increases the economic burden, it is necessary to select the appropriate stiffness and damping value of the outrigger damper system.

• Korean Journal of Psychosomatic Medicine
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• v.12 no.1
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• pp.56-65
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• 2004

Objectives: The aim of this study was to investigate the quality of life of caretaking family members who have a patient with psychiatric disorders. The results will be served as a basic data of ameliorating the quality of life of caregivers. Methods: 78 caretaking family members who have a patient with schizophrenia and 54 caretaking family members who have a patient with alcohol dependence, a total of 132 persons completed the questionnaire, and analyzed. The Korean version of the SmithKline Beecham Quality of Life Scale and the Family Burden Scale were applied. Results: There was no statistically significant correlation between burden and sex, age, income, and duration of living with patients before onset. The male caregiver showed higher quality of life than that of female. It showed statistically significant correlation between age and factor physical well-being and factor activity. 41% of variance of quality of life of caregivers were explained by the stress response, burden, and overall merits of the field of psychiatry, and the tension had the most explanatory power. Conclusion: The chronic illness may give a burden on caregivers, and that decrease the quality of life of caregivers. The longer duration of illness of patients, the lower quality of life of caregivers on competence factor. Therefore, the authors recommend the therapeutic modality must be offered to the caregivers who may experience the stress and burden.

• Tuberculosis and Respiratory Diseases
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• v.82 no.1
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• pp.62-70
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• 2019

Background: Epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancers have emerged as key predictive biomarkers in EGFR tyrosine kinase inhibitor (TKI) treatment. However, a few patients with wild-type EGFR also respond to EGFR TKIs. This study investigated the factors predicting successful EGFR TKI treatment in lung adenocarcinoma patients with wild-type EGFR. Methods: We examined 66 patients diagnosed with lung adenocarcinoma carrying wide-type EGFR who were treated with EGFR TKIs. The EGFR gene copy number was assessed by silver in situ hybridization (SISH). We evaluated the clinical factors and EGFR gene copy numbers that are associated with a favorable clinical response to EGFR TKIs. Results: The objective response rate was 12.1%, while the disease control rate was 40.9%. EGFR SISH analysis was feasible in 23 cases. Twelve patients tested EGFR SISH-positive, and 11 were EGFR SISH-negative, with no significant difference in tumor response and survival between EGFR SISH-positive and -negative patients. The overall median progression-free survival (PFS) and overall survival (OS) of 66 patients were 2.1 months and 9.7 months, respectively. Female sex and Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0-1 were independent predictors of PFS. ECOG PS 0-1 and a low tumor burden of extrathoracic metastasis were independent predictors of good OS. Conclusion: Factors such as good PS, female sex, and low tumor burden may predict favorable outcomes following EGFR TKI therapy in patients with EGFR wild-type lung adenocarcinoma. However, EGFR gene copy number was not predictive of survival.

• Journal of Korean Association for Spatial Structures
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• v.16 no.1
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• pp.95-104
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• 2016

Recently, the concept of damped outrigger system has been proposed for tall buildings. But, structural characteristics and design method of this system were not sufficiently investigated to date. In this study, the dynamic response control performance of outrigger damper has been analyzed. To this end, a simplified analysis model with outrigger damper system has been developed. Use the El Centro seismic(1940, NS) analysis was performed. Analysis results, on the top floor displacement response to the earthquake response, did not have a big effect. However, acceleration response control effect was found to be excellent. The increase of outrigger damper capacity usually results in the improved control performance. However, it is necessary to select that proper stiffness and damping values of the outrigger damper system because, the outrigger damper having large capacity is result in heavy financial burden.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.3
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• pp.361-367
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• 2008

Many trials have been used to model room impulse responses, all attempting to provide efficient representations of room acoustics. The traditional model designs for room impulse response seem to fail in accuracy, controllability, or computational efficiency. In the time domain, room impulse responses are generally considered as combination of the three Parts having different acoustic characteristics, initial time delay, early reflection, and late reverberation. This paper introduces new learning hybrid model for room impulse responses. In this proposed model, those three parts are modeled using different models with learning algorithms that determine the boundary of each model in the hybrid model. By the simulation with measured room impulse responses, the performance of proposed model shows the best efficiency in views of computational burden and modeling error.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.5
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• pp.123-130
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• 2001

The purpose of this paper is to reduce the level of idling vibration on a steering wheel. In some cases, vibration on steering wheel is amplified due to the resonance between the first natural frequency of T-beam and engine idling speed. Using SDM(structural dynamic modification) technique, T-beam is redesigned to reduce its vibration. This paper used FRF(frequency response function) synthesis technique which is entirely dependent on experiment. But this method requires lots of test efforts to enhance its reliability of design. While combining this method with an analytic method. the experimental burden, the major drawback of FRP synthesis method, can be considerably relieved. Using ana1ytic sensitivity analysis, some effective modification regions are preliminarily chosen as candidate Positions where SDM can be applied to modify T-beam\`s dynamic characteristics.