• 한국지진공학회논문집
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• 제22권7호
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• pp.401-409
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• 2018

Performance-based seismic evaluation is usually done by considering simplified models for the liquid storage tanks therefore, it is important to validate those simplified models before conducting such evaluation. The purpose of this study is to compare the seismic response results of the FSI (fluid-structure interaction) model and the simplified models for the cylindrical liquid storage tanks and to verify the applicability of the simplified models for estimating failure probability. Seismic analyses were carried out for two types of storage tanks with different aspect ratios (H/D) of 0.45 and 0.86. FSI model represents detailed 3D fluid-structure interaction model and simplified models are modeled as cantilever mass-spring model, frame type mass-spring model and shell type mass-spring model, considering impulsive and convective components. Seismic analyses were performed with modal analysis followed by time history analysis. Analysis results from all the models were verified by comparing with the results calculated by the code and literature. The results from simplified models show good agreement with the ones from detailed FSI model and calculated results from code and literature, confirming that all three types of simplified models are very valid for conducting failure probability analysis of the cylindrical liquid storage tanks.

• 정보처리학회 논문지
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• 제13권8호
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• pp.388-394
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• 2024

추천 시스템은 기업의 매출 증가로 이어질 만큼 핵심적인 역할을 하기에 추천 시스템에 대한 연구는 과거부터 다양한 접근법과 모델들이 연구되어왔다. 그러나 이러한 다양성으로 인해 추천 시스템의 종류 또한 복잡하게 구성되고 있어 추천 모델을 선택하는 데 어려움이 따른다. 따라서 본 연구는 추천 시스템에서 적절한 추천 모델 선택의 어려움을 해결하고자, 다양한 추천 모델을 구분하는 통합적인 기준을 제공하고, 통일된 환경에서 이들의 성능을 비교 평가하였다. 실험은 MovieLens와 Coursera 데이터셋을 활용하였으며, 선형 모델(ADMM-SLIM, EASER, LightGCN)과 비선형 모델(Caser, BERT4Rec)을 HR@10과 NDCG@10 지표를 통해 성능을 평가하였다. 본 연구는 연구진과 실무자들에게 데이터셋 특성과 추천 상황에 맞는 최적의 모델을 선택하는 데 유용한 정보를 제공할 것이다.

• 대한치과교정학회지
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• 제45권2호
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• pp.82-88
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• 2015

Objective: The aim of this study was to evaluate the reliability of measurements obtained after the superimposition of three-dimensional (3D) digital models by comparing them with those obtained from lateral cephalometric radiographs and photocopies of plaster models for the evaluation of upper molar distalization. Methods: Data were collected from plaster models and lateral cephalometric radiographs of 20 Class II patients whose maxillary first molars were distalized with an intraoral distalizer. The posterior movements of the maxillary first molars were evaluated using lateral cephalometric radiographs (group CP), photocopies of plaster models (group PH), and digitized 3D models (group TD). Additionally, distalization and expansion of the other teeth and the degrees of molar rotation were measured in group PH and group TD and compared between the two groups. Results: No significant difference was observed regarding the amount of molar distalization among the three groups. A comparison of the aforementioned parameters between group PH and group TD did not reveal any significant difference. Conclusions: 3D digital models are reliable to assess the results of upper molar distalization and can be considered a valid alternative to conventional measurement methods.

• 천문학회지
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• 제38권2호
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• pp.267-270
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• 2005

We investigate the spectral energy distributions (SEDs) of low mass-loss rate O-rich asymptotic giant branch (AGB) stars using the infrared observational data including the Infrared Space Observatory (ISO) data. Comparing the results of detailed radiative transfer model calculations with observations, we find that the dust formation temperature is much lower than 1000 K for standard dust shell models. We find that the superwind model with a density-enhanced region can be a possible alternative dust shell model for LMOA stars.

• Communications for Statistical Applications and Methods
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• 제15권5호
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• pp.643-653
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• 2008

Application of the bootstrap to problems in multistage inference procedures are discussed in normal and other related models. After a general introduction to these procedures, here we explore in multistage fixed precision inference in models. We present numerical comparisons of these procedures based on bootstrap critical points for small and moderate sample sizes obtained via extensive sets of simulated experiments. It is expected that the procedure based on bootstrap leads to better results.

• 대한기계학회논문집
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• 제18권8호
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• pp.2201-2209
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• 1994

Macroscopic combustion models used in gun interior ballistic codes are discussed and experimental methods to measure propellant burning rate are reviewed. Comparing with gun firing results, the limit of combustion model is shown and modified combustion model is proposed. But combustion model should be selected with respect to total gun system including propellants.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2003년도 추계학술대회 논문집
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• pp.449-450
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• 2003

Performance of photochemical models and their response to emission controls are heavily dependent on the inputs to the model. Two key inputs to these models are accurate meteorological and emissions data. But they can contain significant errors which contribute to uncertainties in photochemical simulation (Kumar and Russell, 1996; Sistla et al., 1996; Pielke and Uliase, 1998; Barna and Lamb, 2000; Nelson L. Seaman, 2000: Hogrefe et al., 2001; Biswas et al., 2001).(omitted)

• 대한수학회지
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• 제57권4호
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• pp.987-1004
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• 2020

Motivated by the traffic flow model with Arrhenius looka-head relaxation dynamics introduced in [25], this paper proposes a traffic flow model with look ahead relaxation-behind intensification by inserting look behind intensification dynamics to the flux. Finite time shock formation conditions in the proposed model with various types of interaction potentials are identified. Several numerical experiments are performed in order to demonstrate the performance of the modified model. It is observed that, comparing to other well-known macroscopic traffic flow models, the model equipped with look ahead relaxation-behind intensification has both enhanced dispersive and smoothing effects.

• Korean Journal of Geomatics
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• 제4권1호
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• pp.31-37
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• 2004

The aim of this research is comparing the existing approximation models (e.g. Affine Transformation and Direct Linear Transformation) with Rational Function Model as a substitute of rigorous sensor model of linear array scanner, especially push-broom sensor. To do so, this research investigates the mathematical model of each approximation method. This is followed by the assessments of accuracy of transformation from object space to image space by using simulated data generated by collinearity equations which incorporate or depict the physical aspects of linear array sensor.

• Geomechanics and Engineering
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• 제5권2호
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• pp.165-185
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• 2013

In the present study, the numerical and experimental investigations were performed on the backfill- exterior wall-fluid interaction systems in case of empty and full tanks. For this, firstly, the non-linear three dimensional (3D) finite element models were developed considering both backfill-wall and fluid-wall interactions, and modal analyses for these systems were carried out in order to acquire modal frequencies and mode shapes by means of ANSYS finite element structural analysis program. Secondly, a series of field tests were fulfilled to define their modal characteristics and to compare the results from proposed approximation in the selected structures. Finally, comparing the theoretical predictions from the finite element models to results from experimental measurements, a close agreement was found between theory and experiment. Thus, it can be easily stated that experimental verifications provide strong support for the finite element models and the proposed procedures themselves are the meritorious approximations to the real problem, and this makes the models appealing for use in further investigations.