• Title/Summary/Keyword: models

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MODELING SATELLITE IMAGE STRIPS WITH COLLINEARITY-BASED AND ORBIT-BASED SENSOR MODELS

  • Kim, Hyun-Suk;Kim, Tae-Jung
    • Proceedings of the KSRS Conference
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    • v.2
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    • pp.578-581
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    • 2006
  • Usually to achieve precise geolocation of satellite images, we need to get GCPs (Ground control points) from individual scenes. This requirement greatly increases the cost and processing time for satellite mapping. In this article, we focus on finding appropriate sensor models for entire image strips composing of several adjacent scenes. We tested the feasibility of modelling whole satellite image strips by establishing sensor models of one scene with GCPs and by applying the models to neighboring scenes without GCPs. For this, we developed two types of sensor models: collinearity-based type and orbit-based type and tested them using different sets of unknowns. Results indicated that although the performance of two types was very similar, for modelling individual scenes, it was not for modelling the whole strips. Moreover, the performance of sensor models was remarkably sensitive to different sets of unknowns. It was found that the orbit-based model using attitude biases as unknowns can be used to model SPOT image strips of 420 Km in length.

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Development and application of a hierarchical estimation method for anthropometric variables (인체변수의 계층적 추정기법 개발 및 적용)

  • Ryu, Tae-Beom;Yu, Hui-Cheon
    • Journal of the Ergonomics Society of Korea
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    • v.22 no.4
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    • pp.59-78
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    • 2003
  • Most regression models of anthropometric variables use stature and/or weight as regressors; however, these 'flat' regression models result in large errors for anthropometric variables having low correlations with the regressors. To develop more accurate regression models for anthropometric variables, this study proposed a method to estimate anthropometric variables in a hierarchical manner based on the relationships among the variables and a process to develop and improve corresponding regression models. By applying the proposed approach, a hierarchical estimation structure was constructed for 59 anthropometric variables selected for the occupant package design of a passenger car and corresponding regression models were developed with the 1988 US Army anthropometric survey data. The hierarchical regression models were compared with the corresponding flat regression models in terms of accuracy. As results, the standard errors of the hierarchical regression models decreased by 28% (4.3mm) on average compared with those of the flat models.

First Year Undergraduate Students' Difficulties with Ball-and-stick Molecular Models

  • Chue, Shien;Kim, Chwee;Tan, Daniel
    • Journal of The Korean Association For Science Education
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    • v.27 no.6
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    • pp.477-487
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    • 2007
  • Previous studies show that students have difficulties in understanding and using molecular visualization tools. This study focuses on the ways in which first year chemistry undergraduates use ball-and-stick molecular models to explain the concept of addition reaction and the difficulties that they face using the models. Video recordings of interviews with undergraduates manipulating ball-and-stick models to solve problems related to reaction mechanisms are analysed to determine if they are able to elucidate their understanding with use of models. The results showed that students have difficulties with viewing the ball-and-stick models from the proper perspective and understanding the relationship between the various structures that they have created using the models. They also find the use of ball-and-stick models tedious and prefer drawing molecular structures on paper to explain their ideas. Implications for the teaching using ball-and-stick molecular models are discussed.

Streaming of Solid Models Using Cellular Topology (셀룰러 토폴로지를 이용한 솔리드 모델 스트리밍)

  • Lee, Jae-Yeol;Kim, Hyun
    • IE interfaces
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    • v.16 no.spc
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    • pp.87-92
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    • 2003
  • Progressive mesh representation and generation have become one of the most important issues in network-based computer graphics. However, current researches are mostly focused on triangular mesh models. On the other hand, solid models are widely used in industry and are applied to advanced applications such as product design and virtual assembly. Moreover, as the demand to share and transmit these solid models over the network is emerging, the generation and the transmission of progressive solid models depending on specific engineering needs and purpose are essential. In this paper, we present a Cellular Topology-based approach to generating and transmitting progressive solid models from a feature-based solid model for internet-based design and collaboration. The proposed approach introduces a new scheme for storing and transmitting solid models over the network. The Cellular Topology (CT) approach makes it possible to effectively generate progressive solid models and to efficiently transmit the models over the network with compact model size.

Comparative analysis of multiple mathematical models for prediction of consistency and compressive strength of ultra-high performance concrete

  • Alireza Habibi;Meysam Mollazadeh;Aryan Bazrafkan;Naida Ademovic
    • Coupled systems mechanics
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    • v.12 no.6
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    • pp.539-555
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    • 2023
  • Although some prediction models have successfully developed for ultra-high performance concrete (UHPC), they do not provide insights and explicit relations between all constituents and its consistency, and compressive strength. In the present study, based on the experimental results, several mathematical models have been evaluated to predict the consistency and the 28-day compressive strength of UHPC. The models used were Linear, Logarithmic, Inverse, Power, Compound, Quadratic, Cubic, Mixed, Sinusoidal and Cosine equations. The applicability and accuracy of these models were investigated using experimental data, which were collected from literature. The comparisons between the models and the experimental results confirm that the majority of models give acceptable prediction with a high accuracy and trivial error rates, except Linear, Mixed, Sinusoidal and Cosine equations. The assessment of the models using numerical methods revealed that the Quadratic and Inverse equations based models provide the highest predictability of the compressive strength at 28 days and consistency, respectively. Hence, they can be used as a reliable tool in mixture design of the UHPC.

The Comparison of Olson's Circumplex Model and the Beavers' Systems Model in terms of the Relationship between Family Adaptability and Family Function (가족 적응력과 가족기능과의 관계 : Olson의 순환모델의 곡선성과 Beavers의 체계모 델의 선형성)

  • 장진경
    • Journal of Families and Better Life
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    • v.13 no.4
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    • pp.1-14
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    • 1995
  • Various theoretical models have developed io both a family research area and family therapy field on he basis of several family theories and social theories in order to understand the family life and its function. These theoretical models have give rise to provide not only a framework for family therapy bt also opportunities for the development of family studies. Regardless of the devotion of these theoretical models to a family therapy however some family therapy professions have suggested the disvergence between these models and practice because the models tend to confuse therapists in their actual practices Other family therapists on the other hand have claimed the convergence between these models and practice. One of the reasons for the issues of convergence and disvergence in the family therapy study would be that various theoretical models have different sometimes contradicatable definitions and explanations for same concept. Therefore the purpose of this paper is to investigate the extent of similarities and differences among these theoretical models of practice in a way of examining family models to compare Olson's circumplex model to the Beavers systems model. Both models were based on the general systems theory. This paper consists of the explanation of Olson's circumplex model and Beavers systems model in general respectively. Then it will investigate similarities and differences between these two models in terms of the relationship between family functioning and family adaptability.

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Investigation of shear strength models for exterior RC beam-column joint

  • Parate, Kanak;Kumar, Ratnesh
    • Structural Engineering and Mechanics
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    • v.58 no.3
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    • pp.475-514
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    • 2016
  • Various models have been proposed by several researchers for predicting the exterior RC beam-column joint shear strength. Most of these models were calibrated and verified with some limited experimental database. From the models it has been identified that the joint shear strength majorly depends on ten governing parameters. In the present paper, detailed investigation of twelve analytical models for predicting shear strength of exterior beam-column joint has been carried out. The study shows the effect of each governing parameter on joint shear strength predicted by various models. It has been observed that the consensus on effect of few of the governing parameters amongst the considered analytical models has not been attained. Moreover, the predicted joint strength by different models varies significantly. Further, the prediction of joint shear strength by these analytical models has also been compared with a set of 200 experimental results from the literature. It has been observed that none of the twelve models are capable of predicting joint shear strength with sufficient accuracy for the complete range of experimental results. The research community has to reconsider the effect of each parameters based on larger set of test results and new improved analytical models should be proposed.

DEVSim++ - NS2 Interoperating Environment for Protocol Evaluation (프로토콜 평가를 위한 DEVSim++ 와 NS2 의 연동 환경)

  • 김회준;김탁곤
    • Proceedings of the Korea Society for Simulation Conference
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    • 2002.05a
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    • pp.253-258
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    • 2002
  • This paper proposes a methodology for development of protocol models. The methodology attempts to employ two modeling environments in models development, NS2 and DEVSim++, which will interoperate during simulation. NS2 is a widely used network simulator in protocol research, which employs an informal modeling approach. Within the approach time and state information of protocol models are not explicitly described, thus being hard to validate model. On the other hand the DEVS formalism is a mathematical framework for modeling a discrete event system in a hierarchical, modular manner. In DEVS, model's time and state information is described explicitly, By using DEVS formalism, models can easily be validated and errors in the modeling stage can be reduced. However, the DEVS simulator, DEVSim++, supports a small amount of models library which are required to build simulation models of general communication network. Although NS2 employs an informal modeling approach and models validation is difficult, it supports abundant models library validated by experimental users. Thus, combination of DEVS models and NS2 models may be an effective solution for network modeling. Such combination requires interoperation between DEVSim++ simulator and NS2 simulator. This paper develops an environment for such interoperation. Correctness and effectiveness of the implemented interoperation environment have been validated by simulation of UDP and TCP models.

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A recent overview on financial and special time series models (금융 및 특수시계열 모형의 조망)

  • Hwang, S.Y.
    • The Korean Journal of Applied Statistics
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    • v.29 no.1
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    • pp.1-12
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    • 2016
  • Contrasted with the standard linear ARMA models, financial time series exhibits non-standard features such as fat-tails, non-normality, volatility clustering and asymmetries which are usually referred to as "stylized facts" in financial time series context (Terasvirta, 2009). We are accordingly led to ad hoc models (apart from ARMA) to accommodate stylized facts (Andersen et al., 2009). The paper aims to give a contemporary overview on financial and special time series models based on the recent literature and on the author's publications. Various models are illustrated including asymmetric models, integer valued models, multivariate models and high frequency models. Selected statistical issues on the models are discussed, bringing some perspectives to the future works in this area.

The Identification and Comparison of Science Teaching Models and Development of Appropriate Science Teaching Models by Types of Contents and Activities (과학수업모형의 비교 분석 및 내용과 활동 유형에 따른 적정 과학수업모형의 고안)

  • Chung, Wan-Ho;Kwon, Jae-Sool;Choi, Byung-Soon;Jeong, Jin-Woo;Kim, Hyo-Nam;Hur, Myung
    • Journal of The Korean Association For Science Education
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    • v.16 no.1
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    • pp.13-34
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    • 1996
  • The purpose of this study is to develop appropriate science teaching models which can be applied effectively to relevant situations. Five science teaching models; cognitive conflict teaching models, generative teaching model, learning cycle teaching model, hypothesis verification teaching model and discovery teaching model, were identified from the existing models. The teaching models were modified and in primary and secondary students using a nonequivalent pretest-posttest control group design. Major findings of this study were as follows: 1. For teaching science concepts, three teaching models were found more effective; cognitive conflict teaching model, generative teaching model and discovery teaching model. 2. For teaching inquiry skills, two teaching models were found more effective; learning cycle teaching model and hypothesis verification teaching model. 3. For teaching scientific attitudes, two teaching models were found more effective; learning cycle teaching models and discovery teaching model. Each teaching model requires specific learning environment. It is strongly suggested that teachers should select a suitable teaching model carefully after evaluating the learning environment including teacher and student variables, learning objectives and curricular materials.

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