• Title/Summary/Keyword: Hybrid methods

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A Hybrid Data Mining Technique Using Error Pattern Modeling (오차 패턴 모델링을 이용한 Hybrid 데이터 마이닝 기법)

  • Hur, Joon;Kim, Jong-Woo
    • Journal of the Korean Operations Research and Management Science Society
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    • v.30 no.4
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    • pp.27-43
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    • 2005
  • This paper presents a new hybrid data mining technique using error pattern modeling to improve classification accuracy when the data type of a target variable is binary. The proposed method increases prediction accuracy by combining two different supervised learning methods. That is, the algorithm extracts a subset of training cases that are predicted inconsistently by both methods, and models error patterns from the cases. Based on the error pattern model, the Predictions of two different methods are merged to generate final prediction. The proposed method has been tested using practical 10 data sets. The analysis results show that the performance of proposed method is superior to the existing methods such as artificial neural networks and decision tree induction.

Comparison of learning effects between hybrid flipped learning and flipped learning (하이브리드 플립드 러닝과 플립드 러닝의 학습 효과 비교)

  • Bo-ram Choi
    • Journal of Korean Physical Therapy Science
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    • v.31 no.2
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    • pp.90-104
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    • 2024
  • Background: Hybrid learning is an educational approach that combines the teaching methods of online and lecture-style classes to compensate for each method's strengths and weaknesses. Compared to lecture-style classes, flipped learning improves overall class satisfaction and self-directed learning but is associated with lower learning motivation. It is necessary to determine whether hybrid flipped learning can solve the learning motivation problem of flipped learning by incorporating flipped learning into hybrid learning. The purpose of this study is to compare the effects of hybrid flipped learning and flipped learning on students' learning ability. Design: Cross-sectional study Methods: For students in the Department of Physical Therapy, classes were conducted using both flipped learning and hybrid flipped learning. In both learning methods, students took online classes first and participated in them every week. Flipped learning classes was conducted offline at school every week, while hybrid flipped learning alternated between live classes on YouTube and offline classes at school every other week. Results: Hybrid flipped learning resulted in significantly lower learning satisfaction and course evaluation than flipped learning, with no significant difference in grades. Conclusion: Hybrid flipped learning was able to cope with the situation well with the non-face-to-face teaching method caused by COVID-19, but it was difficult to improve learning ability because there were restrictions on activities that could interact with students. Flipped learning is a smooth offline activity that enables two-way activities between professors and students to improve learning ability, but the effect of improving test scores is still unclear.

Enabling role of hybrid simulation across NEES in advancing earthquake engineering

  • Gomez, Daniel;Dyke, Shirley J.;Maghareh, Amin
    • Smart Structures and Systems
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    • v.15 no.3
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    • pp.913-929
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    • 2015
  • Hybrid simulation is increasingly being recognized as a powerful technique for laboratory testing. It offers the opportunity for global system evaluation of civil infrastructure systems subject to extreme dynamic loading, often with a significant reduction in time and cost. In this approach, a reference structure/system is partitioned into two or more substructures. The portion of the structural system designated as 'physical' or 'experimental' is tested in the laboratory, while other portions are replaced with a computational model. Many researchers have quite effectively used hybrid simulation (HS) and real-time hybrid simulation (RTHS) methods for examination and verification of existing and new design concepts and proposed structural systems or devices. This paper provides a detailed perspective of the enabling role that HS and RTHS methods have played in advancing the practice of earthquake engineering. Herein, our focus is on investigations related to earthquake engineering, those with CURATED data available in their entirety in the NEES Data Repository.

Seismic reliability evaluation of steel-timber hybrid shear wall systems

  • Li, Zheng;He, Minjuan;Lam, Frank;Zhou, Ruirui;Li, Minghao
    • Earthquakes and Structures
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    • v.13 no.3
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    • pp.289-297
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    • 2017
  • This paper presents seismic performance and reliability evaluation on steel-timber hybrid shear wall systems composed of steel moment resisting frames and infill light frame wood shear walls. Based on experimental observations, damage assessment was conducted to determine the appropriate damage-related performance objectives for the hybrid shear wall systems. Incremental time-history dynamic analyses were conducted to establish a database of seismic responses for the hybrid systems with various structural configurations. The associated reliability indices and failure probabilities were calculated by two reliability methods (i.e., fragility analysis and response surface method). Both methods yielded similar estimations of failure probabilities. This study indicated the greatly improved seismic performance of the steel-timber hybrid shear wall systems with stronger infill wood shear walls. From a probabilistic perspective, the presented results give some insights on quantifying the seismic performance of the hybrid system under different seismic hazard levels. The reliability-based approaches also serve as efficient tools to assess the performance-based seismic design methodology and calibration of relative code provisions for the proposed steel-timber hybrid shear wall systems.

The Comparison of Characteristics in various Speaker Adaptation Methods (여러 화자 적응 방법들의 특성 비교)

  • 황영수
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1998.06e
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    • pp.339-342
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    • 1998
  • In this paper, we proposed various speaker adaptation methods and studied the performance of these methods. Methods which were studied in this paper are MAPE(Maximum A Posteriori Probability Estimation), ARTMAP. In order to evaluate the performance of these methods, we used Korean isolated digits as the experimental data, the hybrid speaker adaptation method, which unfied MAPE, linear spectral estimating and outpur probability of SCHMM, showed the better recognition result than those which performed other methods. And the method using ARTMAP showed the similar result to above hybrid method.

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Prediction of Wave Energy Absorption Efficiency of a Flp-Harbour Device by a Hybrid Integral Equation (Hybrid 적분방정식을 사용한 Flap-Harbour 복합체 파 에너지 흡수효율 추정)

  • 김현주
    • Journal of Ocean Engineering and Technology
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    • v.14 no.2
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    • pp.1-6
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    • 2000
  • Wave energy absorption by a flap equipped with a harbor in a water of finite depth is studied. The wave potential is calculated by a hybrid integral equation consisting of Green integral equations associated with Rankine and Kelvin Green functions. The absorbed wave energy is calculated by both the near-field and far-field methods. The present methods can be used for the design of a flap-harbor wave energy absorber since the numerical results by the two methods are in good agreement.

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Transient Characteristics Improvement Using Hybrid Control for Inverter Systems (하이브리드 제어에 의한 인버터 시스템의 과도특성 향상)

  • Kim, Gyu-Sik
    • Journal of The Institute of Information and Telecommunication Facilities Engineering
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    • v.3 no.2
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    • pp.5-10
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    • 2004
  • In this paper, the hybrid-type current controller for inverter TIG systems was implemented and it was shown that the low-current pulse wave forms with high dynamic performance could be obtained. It is not sri easy to obtain the optimum gain tuning of PID controllers in digital PWM control methods. Hybrid control methods which uses automatic tuning techniques after adding fuzzy control methods to traditional PID controllers are chosen to improve the dynamic performance of PID controller's. To demonstrate the practical significance and dynamic performance improvement of the results, some simulation and experimental results are presented.

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Human Papillomavirus Testing with Hybrid Capture II and DNA Chip

  • Im Jee-Aee;Shim Moon-Jung;Ryang Yong-Suk;Lee Duk-Chul
    • Biomedical Science Letters
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    • v.11 no.1
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    • pp.51-56
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    • 2005
  • The detection of high-risk human papilloma virus (HPV) allows us to predict the presence and future development of cervical intraepitheliallesion. In this study, we compared Hybrid Capture II and DNA chip methods for detection of HPV in cervical swab samples. And we evaluated the clinical efficacy and diagnostic performance of HPV DNA chip and Hybrid Capture II for detecting HPV in cervical neoplastic lesions. Seventy four patients were classified into three groups according to their histologic diagnosis: Group I (nonspecific chronic cervicitis), Group II (low-grade squamous intraepithelial lesion (SIL); koilocytosis, and mild dysplasia), and Group III (high-grade SIL;, moderate, severe dysplasia and in situ carcinoma). Cytologic diagnosis were based on the Bethesda System. Hybrid Capture II and DNA chip methods were performed to detect HPV. In 41 of the 74 cervical samples $(55.4\%)$, HPV DNAs were detected by Hybrid Capture II. In Group III, HPV-positive cases were detected in 15 $(20.3\%)$ of 74 patients by Hybrid Capture II. 25 patients with ASCUS cytology were histopathologically examined: 9 cases $(36\%)$ were Group II. In 18 patients with low-grade SIL cytology, 13 cases $(72.2\%)$ were Group II and 3 cases $(16.7\%)$ were Group III. 12 cases $(92.3\%)$ were Group ill of 13 patients with high-grade SIL cytology. The sensitivity of each test was $82\%$ in Hybrid Capture II and $53.9\%$ in DNA chip test. And the specificity was $74.3\%,\;85.7\%$ in Hybrid Capture II and DNA chip. In conclusion, Hybrid Capture II test is more sensitive than DNA chip in detecting women with cervical neoplastic lesions. Especially, in diagnosing of ASCUS, Hybrid Capture II test is more sensitive. Therefore, Hybrid Capture II test for cancer-associated HPV DNA is a viable option in the management of women with ASCUS.

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Heuristics for Line Balancing in Hybrid Flowshops (혼합 흐름공정에서 라인 밸런싱을 위한 휴리스틱 개발)

  • Lee, Geun-Cheol
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.30 no.3
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    • pp.94-102
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    • 2007
  • In this paper, we consider a line balancing problem in hybrid flowshops where each workstation has identical parallel machines. The number of machines in each workstation is determined in ways of satisfying pre-specified throughput rate of the system. To minimize the total number of machines in the systems, we propose five heuristic methods and one simulated annealing method. Extensive computational experiments found the superiorities of two heuristic methods and the meta-heuristic.

Numerical Comparisons Between URANS and Hybrid RANS/LES at a High Reynolds Number Flow Using Unstructured Meshes

  • You, Ju-Yeol;Kwon, Oh-Joon
    • International Journal of Aeronautical and Space Sciences
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    • v.11 no.1
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    • pp.41-48
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    • 2010
  • In the present study, the turbulent flow fields around a circular cylinder at $Re=3.6{\times}10^6$ were investigated based on an unstructured mesh technique, and the comparisons between URANS(S-A, SST) and hybrid RANS/LES(DES, SAS) methods for the simulation of high Reynolds number flow have been conducted. For this purpose, unsteady characteristics of vortex shedding and time-averaged quantities were compared. A quasi-steady solution-adaptive mesh refinement was also made for the URANS and hybrid RANS/LES approaches. The results showed that the simple changes in the turbulent length scale or source term of turbulent models made the flow fields less dissipative and more realistic in hybrid RANS/LES methods than the URANS approaches.