• 대한수학회보
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• 제50권5호
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• pp.1711-1723
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• 2013

P. V$\acute{a}$mos called a ring R 2-good if every element is the sum of two units. The ring of all $n{\times}n$ matrices over an elementary divisor ring is 2-good. A (right) self-injective von Neumann regular ring is 2-good provided it has no 2-torsion. Some of the earlier results known to us about 2-good rings (although nobody so called at those times) were due to Ehrlich, Henriksen, Fisher, Snider, Rapharl and Badawi. We continue in this paper the study of 2-good rings by several authors. We give some examples of 2-good rings and their related properties. In particular, it is shown that if R is an exchange ring with Artinian primitive factors and 2 is a unit in R, then R is 2-good. We also investigate various kinds of extensions of 2-good rings, including the polynomial extension, Nagata extension and Dorroh extension.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제5권1호
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• pp.64-68
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• 2005

We introduce in Sostak's fuzzy topological spaces definitions of paracompactness, almost paracompactness, and near paracompactness all of which turn to be good extensions of their classical topological counterparts. Fuzzy semi-paracompact, para S-closed and weakly paracompact spaces are treated to a similar approach.

• 한국지능시스템학회논문지
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• 제13권5호
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• pp.614-620
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• 2003

The aim of this paper is to introduce good definitions of compactness, almost compactness, near compactness, weak compactness, and S-closedness in fuzzy topological spaces in Sostak s sense. These compactness related concepts are defined for arbitrary fuzzy sets and some of their properties studied.

• Computers and Concrete
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• 제1권2호
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• pp.189-209
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• 2004

Several extensions to the Thelandersson phenomenological model for concrete under transient high temperatures are explored. These include novel expressions for the temperature degradation of the elastic modulus and the temperature dependency of the coefficient of the free thermal strain. Furthermore, a coefficient of thermo mechanical strain is proposed as a bi-linear function of temperature. Good qualitative agreement with various test results taken from the literature is demonstrated. Further extensions include the effects of plastic straining and temperature dependent Poisson's ratio. The models performance is illustrated on several simple benchmark problems under uniaxial and biaxial stress states.

• 한국지능시스템학회논문지
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• 제10권6호
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• pp.564-568
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• 2000

We introduce in L-smooth topological spaces definitions of paracompactness, almost paracompactness and near paracompactness all of which turn out to be good extensions of their classical topological counterparts. These weak paracompactness are defined for arbitrary L-fuzzy sets and their properties studied.

• 대한기계학회논문집
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• 제14권1호
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• pp.103-111
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• 1990

본 연구에서는 성장하는 균열선단에서 열림변위의 임계증분에 대한 균열성장 조건에 기본을 두고 계산된 파단하중을 실험결과와 비교하여 균열성장저항을 특성 지 을수 있는 새로운 재료상수를 제안한 것이다.

• Communications for Statistical Applications and Methods
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• 제24권4호
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• pp.383-396
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• 2017

The model in our approach assumes that computer responses are a realization of a Gaussian processes superimposed on a regression model called a Gaussian process regression model (GPRM). Selecting a subset of variables or building a good reduced model in classical regression is an important process to identify variables influential to responses and for further analysis such as prediction or classification. One reason to select some variables in the prediction aspect is to prevent the over-fitting or under-fitting to data. The same reasoning and approach can be applicable to GPRM. However, only a few works on the variable selection in GPRM were done. In this paper, we propose a new algorithm to build a good prediction model among some GPRMs. It is a post-work of the algorithm that includes the Welch method suggested by previous researchers. The proposed algorithms select some non-zero regression coefficients (${\beta}^{\prime}s$) using forward and backward methods along with the Lasso guided approach. During this process, the fixed were covariance parameters (${\theta}^{\prime}s$) that were pre-selected by the Welch algorithm. We illustrated the superiority of our proposed models over the Welch method and non-selection models using four test functions and one real data example. Future extensions are also discussed.

• 대한화학회지
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• 제43권6호
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• pp.621-627
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• 1999

순이론적인 계산으로부터 얻은 전체 에너지로부터 탄화수소의 생성 엔탈피를 계산하는 새로운 방법을 제안하여였다. 이 방법은 결합 파라미터를 도입하여 원자의 전체 갯수에 근거를 두는 과거의 방법론을 개선한 것이다. 현 방법론의 결과는 우수하며 생성 엔탈피 계산의 평균오차는 실험 오차보다 작은 것으로 나타났다. 제안하는 방법론을 확실히 하기 위한 몇 가지 가능한 확장법도 제시하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1621-1626
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• 2000

A simplified modeling approach for occupied car seats was demonstrated to be feasible. The model, consisting of interconnected masses, springs and dampers, was initially broken down into subsystems and experiments conducted to determine approximate values for model parameters. A short study of the effect of changing model parameters on natural frequencies, mode shapes and resonance locations in frequency response functions was given, highlighting the influence of particular model parameters on features in the mannequin's vibration response. Good agreement between experimental and simulation frequency response estimates was obtained. Future work should include optimization of parameter estimates, the inclusion of viscoelastic and nonlinear elements in addition to the linear springs and dampers, and finally extensions to a 3D model.

• Computers and Concrete
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• 제25권5호
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• pp.461-470
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• 2020

This paper presents a numerical study on structural behavior of hammer head pier cap beams, extended on verges and reinforced with carbon fiber reinforced polymer (CFRP) plates. A 3-D finite element (FE) model along with a simplified analytical model are presented. Concrete damage plasticity (CDP) was adapted in the FE model and an analytical approach predicting the CFRP anchor strength was adapted in both FE and analytical model. Total five quarter-scaled pier cap beams with various CFRP reinforcing schemes were experimentally tested and analyzed with numerical approaches. Comparison between experimental results, FE results, analytical results and current ACI guideline predictions was presented. The FE results showed good agreement with experimental results in terms of failure mode, ultimate capacity, load-displacement response and strain distribution. In addition, the proposed strut-and-tie based analytical model provides the most accurate prediction of ultimate strength of extended cap beams among the three numerical approaches.