• Journal of Electrical Engineering and Technology
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• 제5권3호
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• pp.493-496
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• 2010

At present, Metal Oxide gas Sensors (MOXs) are widely used in gas detection because of its advantages, including high sensitivity and low cost. However, MOX presents well-known problems, including lack of selectivity and environment effect, which has motivated studies on different measurement strategies and signal-processing algorithms. In this paper, we present an artificial neural network (ANN) that models an MOX sensor (TGS822) used in a dynamic environment. This model takes into account dependence in relative humidity and in gas nature. Using MATLAB interface in the design phase and optimization, the proposed model is implemented as a component in an electronic simulator library and accurately expressed the nonlinear character of the response and that its dependence on temperature and relative humidity were higher than gas nature.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.488-493
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• 2013

Accurate initial cost estimates are essential to effective management of construction projects where many decisions are made in the course of project management by referencing the estimates. In practice, the initial estimates are frequently derived from historical actual cost data, for which standard distribution-based techniques are widely applied in the construction industry to account for risk associated with the estimates. This approach assumes the same probability distribution of estimate errors for any selected estimates. This assumption, however, is not always satisfied. In order to account for the probabilistic nature of estimate errors, an alternative method for measuring the risk associated with a selected initial estimate is developed by applying the Bayesian probability approach. An application example include demonstrates how the method is implemented. A hypothesis test is conducted to reveal the robustness of the Bayesian probability model. The method is envisioned to effectively complement cost estimating methods that are currently in use by providing benefits as follows: (1) it effectively accounts for the probabilistic nature of errors in estimates; (2) it is easy to implement by using historical estimates and actual costs that are readily available in most construction companies; and (3) it minimizes subjective judgment by using quantitative data only.

• Environmental Analysis Health and Toxicology
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• 제31권
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• pp.8.1-8.2
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• 2016

A simple linear model to test the hypothesis based on one-on-one relationship has been used to find the causative factors of diseases. However, we now know that not just one, but many factors from different systems such as chemical exposure, genes, epigenetic changes, and proteins are involved in the pathogenesis of chronic diseases such as diabetes mellitus. So, with availability of modern technologies to understand the intricate nature of relations among complex systems, we need to move forward to the future by taking complex systems model.

• 제어로봇시스템학회논문지
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• 제15권9호
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• pp.929-938
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• 2009

This paper presents a novel control methodology for communication network based nonlinear systems with time delay nature. We construct a nominal nonlinear control law for representing a linear model and a reset control system which is aimed for corrective control strategy to compensate system error due to uncertain time delay through wireless communication network. Next, online neural control approach is proposed for overcoming nonstationary statistical nature in the network topology. Additionally, DBN (Dynamic Bayesian Network) technique is accomplished for modeling of its dynamics in terms of casuality, which is then utilized for estimating prediction of system output. We evaluate superiority and reliability of the proposed control approach through numerical simulation example in which a nonlinear inverted pendulum model is employed as a networked control system.

• 한국철도학회논문집
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• 제5권4호
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• pp.209-214
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• 2002

Belief revision involves integrating new information with the current belief. It is a ubiquitous human activity. A critical feature of belief revision lies in its sequential nature. Railroad system can be described as organic. Engine drivers take a great role in this system. Recently, Hogarth and Einhorn(1992) have posited a belief-adjustment model for updating beliefs. Based on a sequential anchoring and adjustment strategy, the model is important for decision makers. The sequential nature of information processing is affected by some task variables. The purpose of this study is to examin factors which influnce on the Enginr Driver's belief revision process. The factors are the order, experience and task. The difference of belief revision is due to the order and experience level.

• 대한화학회지
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• 제62권3호
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• pp.226-234
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• 2018

본 연구는 화학영역에서 뜨고 가라앉는 현상과 관련되어 교과서에 진술된 모델을 모델의 생성과 관련된 본성 측면을 기반으로 평가하였다. 이를 알아보기 위해 7차 교육과정에서부터 2009 개정 교육과정의 초등학교 3학년 과학교과서 2종과 중학교 과학교과서 21종이 분석되어졌다. 분석 결과 진술된 모델은 (1) 모델의 전제조건에 대한 설명 부재, (2) 물질적 관점의 질술 방식, (3) 패턴의 원리 결여, (4) 다루어진 사례의 부적절성의 특성을 보였다. 학생들에 대한 모델의 교육은 모델을 이용한 활동 보다는 모델이 생성되는 과정과 관계된 교육이 선행되어야 함에도 그러한 모델의 본성에 대한 교육이 부족함을 알 수 있었다. 이를 해결하기 위해 모델의 생성과 관련된 모델의 진술과 이와 관련된 학생 모델 평가 도구 제작을 제언하였다.

• 한국환경과학회지
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• 제24권11호
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• pp.1451-1461
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• 2015

The purpose of this study is to describe how nature-based ecotourism motivation of ecotourists influences destination image and satisfaction of ecotourists. In order to achieve the above purposes, the study carried out a literature study and an empirical analysis. Based on the obtained data through the literature study, the study designed a model for the empirical study. The results of this study are as follows. First, returns to nature, knowledge. fitness and escape as ecotourism motivation of ecotourist had a positive effect on each ecotourism destination image, such as cognitive and affective image. However, effect of novelty on cognitive image for destination had not significant results. Second, ecotourism destination image, such as cognitive and affective image, had a positive effect on ecotourism satisfaction of ecotourists. The results of the article provide implications for strategies for promoting ecotourism destination and suggest some guidelines for the eco-education of tourists.

• 과학교육연구지
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• 제39권1호
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• pp.15-27
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• 2015

본 연구에서는 과학의 본성을 현대적 관점으로 변화시킬 수 있는 프로그램으로서 2 종류의 과학사-역할놀이 프로그램을 고안하여 그 프로그램의 적용 효과와 과학사 주제별 과학의 본성의 인식의 변화에서 차이가 있는 지를 알아보았다. 과학사 주제에 따른 역할놀이 활동 전후의 과학의 본성 인식변화 효과의 차이를 분석한 결과 I 그룹(원자모형의 변천-역할놀이 활동)과 II 그룹(멘델레프 주기율 표-역할놀이 활동)을 수행한 그룹 사이에 과학의 본성 인식 정도가 통계적으로 차이가 없는 동질한 그룹이었으나, 각각의 주제로 과학사-역할놀이 처치를 한 후 시행한 사후검사에서 I 그룹이 II 그룹보다 그 인식의 정도가 통계적으로 유의미한 차이로 높게 나타났다. 이는 과학사-역할놀이 활동을 처치한 후에 과학의 본성에 대한 인식의 변화 정도는 각각의 역할놀이와 결합시키는 과학사의 주제에 따라 그 효과가 차이가 있을 수 있음을 의미하는 것이다. 본 연구결과는 주제의 흥미도와 난이도를 고려하기 보다는 시계열적 과정을 거쳐 다수의 과학자들이 과학적 이론을 정립해 가는 과정이 포함된 과학사 주제를 선택하여 과학사-역할놀이 활동을 할 경우 과학의 본성의 변화에 더 효과적일 수 있다는 가능성을 시사한다.

• 한국정밀공학회지
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• 제29권1호
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• pp.33-40
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• 2012

The scaffold serves as 3D substrate for the cells adhesion and mechanical support for the newly grown tissue by maintaining the 3D structure for the regeneration of tissue and organ. In this paper, we proposed integrated scaffold fabrication system using multi-axis rapid prototyping (RP) technology. It can fabricate various types of scaffolds: arbitrary sculptured shape, primitive shape, and tube shape scaffolds by layered dispensing biocompatible/ biodegradable polymer strands in designated patterns. In order to fabricate the 3D scaffold, we need to generate the plotting path way for the scaffold fabrication system. We design a data processing program - scaffold plotting software, which can convert the 3D STL file, primitive and tube model images into the NC code for the system. Finally, we fabricated the customized 3D scaffolds with high accuracy using the plotting software and the fabrication system.

• Advances in concrete construction
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• 제14권1호
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• pp.71-77
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• 2022

Creep phenomenon affects the stability and integrity of concrete structures. An inaccurate prediction of these strains may lead to the appearance of cracks and excessive deflections which may cause in some cases the demolition of structures. In fact, the measured values of these uncontrolled strains appear often to be clearly different and larger than the expected ones. Therefore, an accurate prediction of concrete deformations is a necessity. As a matter of fact, the codified descriptions of this phenomenon are unreliable and don't consider the effect of admixtures. The physical nature of creep is not well understood and almost all creep models are mainly of empirical nature. To overcome this issue, a study of the correlation between different parameters affecting concrete creep is performed and a new model for predicting creep of concrete is elaborated. This new model considers the effect of admixtures, specifically the silica fume, in predicting concrete creep and allows an accurate prediction of this phenomenon. The proposed model is based on the observation of physical behavior of creep phenomenon. It targets at expressing creep compliance in terms of structural and environmental parameters. In fact, the experimental observations show that creep curves follow two kinetic regimes leading to a model called Phenomenological Creep Model. By adequate regressions and substitutions, and according to this model, we can express creep compliance in terms of structural, environmental parameters and admixture types and percentage. The proposed new Phenomenological Creep Model Silica Fume (PCM19SF) calculates accurately creep of concrete by considering the effect of silica fume.