• Earthquakes and Structures
• /
• v.3 no.3_4
• /
• pp.457-471
• /
• 2012

Current code procedures for stress and stability analysis of new and existing concrete-gravity dams are primarily based on conventional methods of analysis. Such methods can be applied in a straightforward manner but there has been evidence that they may be inaccurate or, possibly, not conservative. This paper presents finite element modeling and analysis procedures and makes recommendations for local failure criteria at the dam-rock interface aimed at predicting more accurately the behavior of dams under hydraulic and anchoring loads.

• Journal of applied mathematics & informatics
• /
• v.33 no.5_6
• /
• pp.657-670
• /
• 2015

In this paper, we provide numerical analysis of so-called Legendre Gauss-Radau and Legendre-Gauss collocation methods for ordinary differential equations. After recasting these collocation methods as Runge-Kutta methods, we prove that the Legendre-Gauss collocation method is equivalent to the well-known Gauss method, while the Legendre-Gauss-Radau collocation method does not belong to the classes of Radau IA or Radau IIA methods in the Runge-Kutta literature. Making use of the well-established theory of Runge-Kutta methods, we study stability and accuracy of the Legendre-Gauss-Radau collocation method. Numerical experiments are conducted to confirm our theoretical results on the accuracy and numerical stability of the Legendre-Gauss-Radau collocation method, and compare Legendre-Gauss collocation method with the Gauss method.

• Phonetics and Speech Sciences
• /
• v.3 no.2
• /
• pp.71-78
• /
• 2011

In this paper, we propose an approach which constructs classifier ensembles of various channel compensation and feature enhancement methods. CMN and CMVN are used as channel compensation methods. PCA, kernel PCA, greedy kernel PCA, and kernel multimodal discriminant analysis are used as feature enhancement methods. The proposed ensemble system is constructed with the combination of 15 classifiers which include three channel compensation methods (including 'without compensation') and five feature enhancement methods (including 'without enhancement'). Experimental results show that the proposed ensemble system gives highest average speaker identification rate in various environments (channels, noises, and sessions).

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.19 no.2
• /
• pp.171-188
• /
• 2015

In this paper, the efficient column-wise/row-wise lattice reduction (LR) updating and downdating methods are developed and their complexities are analyzed. The well-known LLL algorithm, developed by Lenstra, Lenstra, and Lov${\acute{a}}$sz, is considered as a LR method. When the column or the row is appended/deleted in the given lattice basis matrix H, the proposed updating and downdating methods modify the preconditioning matrix that is primarily computed for the LR with H and provide the initial parameters to reduce the updated lattice basis matrix efficiently. Since the modified preconditioning matrix keeps the information of the original reduced lattice bases, the redundant computational complexities can be eliminated when reducing the lattice by using the proposed methods. In addition, the rounding error analysis of the proposed methods is studied. The numerical results demonstrate that the proposed methods drastically reduce the computational load without any performance loss in terms of the condition number of the reduced lattice basis matrix.

• The Research Journal of the Costume Culture
• /
• v.10 no.6
• /
• pp.601-616
• /
• 2002

Qualitative research is a method widely used in marketing research. However, the method has seldom been used in fashion marketing research in Korea. The purpose of this study was to prove that using both qualitative and quantitative research methods in main stage is much useful than using qualitative research method only in exploratory stage. Qualitative data were gathered by conducting Focus Group Interview(FGI) with 48 college students. Quantitative data were gathered by surveying college students, and 487 questionnaires were used in the statistical analysis. The data were analyzed using content analysis, mean, standard deviation, and t-test. As a result, FGI, one of the tools used in qualitative research methods, was proved to be useful in revealing consumers´deep emotional needs as well as purchase motives. FGI also revealed information which quantitative research method tools such as survey could have missed. Therefore, it is best to use multiple methods-simultaneous use of quantitative and qualitative methods-to understand fast changing consumers´needs and purchase motives.

• Journal of Korea Society of Industrial Information Systems
• /
• v.23 no.2
• /
• pp.63-73
• /
• 2018

Academia and research institutes mainly use qualitative methods that rely on expert judgments to understand and predict research trends and science and technology trends. Since such a technique has the disadvantage of requiring much time and money, in this study, science and technology trends were predicted using keyword network analysis. To that end, 13,618 AI (Artificial Intelligence) patent abstracts were analyzed using keyword network analysis in three separate lots based on the period of the submission of each abstract: analysis period 1 (January 1, 2002 - December 31, 2006), analysis period 2 (January 1, 2007 - December 31, 2011), and analysis period 3 (January 1, 2012 - December 31, 2016). According to the results of frequency analyses, keywords related to methods in the field of AI application appeared more frequently as time passed from analysis period 1 to analysis period 3. In keyword network analyses, the connectivity between keywords related to methods in the field of AI application and other keywords increased over time. In addition, when the connected keywords that showed increasing or decreasing trends during the entire analysis period were analyzed, it could be seen that the connectivity to methods and management in the field of AI application was strengthened while the connectivity to the field of basic science and technology was weakened. According to analysis of keyword connection centrality, the centrality value of the field of AI application increased over time. According to analysis of keyword mediation centrality during analysis period 3, keywords related to methodologies in the field of AI application showed the highest mediation value. Therefore, it is expected that methods in the field of AI application will play the role of powerful intermediaries in AI hereafter. The technique presented in this paper can be employed in the excavation of tasks related to regional innovation or in fields such as social issue visualization.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.42 no.5
• /
• pp.571-578
• /
• 1997

The development of new approaches for wheat grain hardness assessment may impact the grain industry in marketing, milling and breeding. This experiment was to develop a new method for fast identification between softness and hardness, and for maintaining germinability of seed after measurement in wheat. Results from the comparisons of accuracy and significance between image analysis and conventional methods(NIRS and textrometer) were summarized. Data obatined from image analysis for grain hardness did not show any difference from those of the conventional methods. The protein content analyzed by micro-Kjeldahl method was significantly correlated with the grain hardness measured by image analysis, textrometer, and NIRS. The analysis for wheat grain hardness using image analysis may be used as an alternative method to the conventional methods. This method also takes the seeds after analysis can be utilized as breeding materials in early generations.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
• /
• 1994.11a
• /
• pp.288-302
• /
• 1994

A security risk analysis provides all information system with the capability to investigate and estimate the status of its security, and gives a guideline for establishing a safeguard against any means of security threats. The information system needs tile judicious and accurate why for performing a risk analysis since security policy and risk analysis of tile information system are based on risk analysis, The risk analysis is composed of two methods. mathematical approach and diagramming technique. Mathematical approach cannot yield a precise description of the real world. However, diagramming technique is more pragmatic since it overcomes this limitation. In this paper, we studied tile security risk analysis methods proposed in overseas such as INFOSEC [4], SRAG [5], FIPS65[6], and JRAM[7].

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.14 no.2
• /
• pp.69-76
• /
• 2018

The paper presents preliminary investigation results for the effect of the baseline correction in the acceleration excitation method on finite element seismic analysis results (such as accumulated equivalent plastic strain, equivalent plastic strain considering cyclic plasticity, von Mises effective stress, etc) of nuclear safety Class I components. For investigation, finite element elastic-plastic time-history seismic analysis is performed for a surge line including a pressurizer lower head, a pressurizer surge nozzle, a surge piping, and a hot leg surge nozzle using the Chaboche hardening model. Analysis is performed for various seismic loading methods such as acceleration excitation methods with and without the baseline correction, and a displacement excitation method. Comparing finite element analysis results, the effect of the baseline correction is investigated. As a result of the investigation, it is identified that finite element analysis results using the three methods do not show significant difference.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.21 no.1
• /
• pp.165-173
• /
• 2023

Various linear system solvers with multi-physics analysis schemes are compared focusing on the near-field region considering thermal-hydraulic-chemical (THC) coupled multi-physics phenomena. APro, developed at KAERI for total system performance assessment (TSPA), performs a finite element analysis with COMSOL, for which the various combinations of linear system solvers and multi-physics analysis schemes should to be compared. The KBS-3 type disposal system proposed by Sweden is set as the target system and the near-field region, which accounts for most of the computational burden is considered. For comparison of numerical analysis methods, the computing time and memory requirement are the main concerns and thus the simulation time is set up to one year. With a single deposition hole problem, PARDISO and GMRES-SSOR are selected as representative direct and iterative solvers respectively. The performance of representative linear system solvers is then examined through a problem with an increasing number of deposition holes and the GMRES-SSOR solver with a segregated scheme shows the best performance with respect to the computing time and memory requirement. The results of the comparative analysis are expected to provide a good guideline to choose better numerical analysis methods for TSPA.