• Title/Summary/Keyword: Data Modelling

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Architecture Support for Context-aware Adaptation of Rich Sensing Smartphone Applications

  • Meng, Zhaozong
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.1
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    • pp.248-268
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    • 2018
  • The performance of smartphone applications are usually constrained in user interactions due to resource limitation and it promises great opportunities to improve the performance by exploring the smartphone built-in and embedded sensing techniques. However, heterogeneity in techniques, semantic gap between sensor data and usable context, and complexity of contextual situations keep the techniques from seamless integration. Relevant studies mainly focus on feasibility demonstration of emerging sensing techniques, which rarely address both general architectures and comprehensive technical solutions. Based on a proposed functional model, this investigation provides a general architecture to deal with the dynamic context for context-aware automation and decision support. In order to take advantage of the built-in sensors to improve the performance of mobile applications, an ontology-based method is employed for context modelling, linguistic variables are used for heterogeneous context presentation, and semantic distance-based rule matching is employed to customise functions to the contextual situations. A case study on mobile application authentication is conducted with smartphone built-in hardware modules. The results demonstrate the feasibility of the proposed solutions and their effectiveness in improving operational efficiency.

Estimation of Spatial Dependence by Quasi-likelihood Method (의사우도법을 이용한 공간 종속 모형의 추정)

  • 이윤동;최혜미
    • The Korean Journal of Applied Statistics
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    • v.17 no.3
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    • pp.519-533
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    • 2004
  • In this paper, we suggest quasi-likelihood estimation (QLE) method and its robust version in estimating spatial dependence modelled through variogram used for spatial data modelling. We compare the statistical characteristics of the estimators with other popular least squares estimators of parameters for variogram model by simulation study. The QLE method for estimating spatial dependence has the advantages that it does not need the concept of lags commonly required for least squares estimation methods as well as its statistical superiority. The QLE method also shows the statistical superiority to the other methods for the tested Gaussian and non-Gaussian spatial processes.

A Digital System Modelling for Narrow Band ISDN and A Decision Methodology of Channel Capacity Limitation (협대역 ISDN을 위한 디지털 시스템 모델링과 통신로 용량의 한계 결정)

  • 이종현;성태경;신용옥
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.6
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    • pp.591-597
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    • 1988
  • In this paper, we have studied a channel capacity affected by noise which produces burst errors in the ISDN(approx 140Kbps) data transmission using a existing PSTN. First, a digital communication system model to apply a subscriber line to a narrow band ISDN channel is presented. Second, the decision methodology of a channel capacity limitation whether the pdf of the noise generated by a waveform synthesizer is Pisson or Laplacian is described. As a result of the simulation, we have obtained that the Poission distributed noise is approached to the Guassian rather than the Laplacian under the same SNR condition.

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A Study on the Pullout Behavior of Ground Anchored in Weatherd Rock (풍화암에 근입된 그라운드 앵커의 인발거동 연구)

  • Park, Byung-Soo;Jeong, Gil-Soo;Jeon, Sang-Hyun;Yoo, Nam-Jae
    • Journal of Industrial Technology
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    • v.26 no.A
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    • pp.109-117
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    • 2006
  • This study is an numerical study of predicting the behavior of anchor embedded in weathered rocks, subjected to uplift loads, about ultimate pullout capacity and the failure mechanism. Factors influencing the behavior of anchors were investigated by reviewing the data about in-situ anchor tests performing numerical modelling with changing the bondage length of anchor, diameter of anchor body and diameter of tenden, and by Correlations between those factors were evaluated to apply them to predict the behavior of anchors. As results of numerical analysis, a linear relationship between bondage length, diameter of anchor body and diameter of tenden with ultimate pullout capacity was obtained on the one hand, from the result of numerical analysis changing the Young's modulus of weathered rock, this parameter was found to inflence to load-displacement and ultimate pullout capacity within the range of 10%, which was mot so significant to affect.

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Modelling of I-V Characteristics of PV module with resistance variation (PV 모듈의 손실 저항 성분을 고려한 I-V 출력 모델링에 관한 연구)

  • Hong, Jong-Kyuong;Jung, Tae-Hee;Ryu, Se-Hwan;Won, Chang-Sub;Kang, Gi-Hwan;Ahn, Hyung-Keun;Han, Deuk-Young
    • Proceedings of the KIEE Conference
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    • 2008.10c
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    • pp.177-179
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    • 2008
  • This paper, we proposed the theoretical model which includes series resistance $R_s$ and shunt resistance $R_{sh}$ of single-crystalline PV module and used numerical method based on physics. Series resistance $R_s$ was derived from approach for p-n junction diode instead of established form obtained from the simulator with irradiance changes. Electrical output characteristics for PV modules to count the effect of $R_s$ were then studied. Finally simulation results were compared to experimental data leading to good agreement.

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Study on comparisons between PSS/E and Matlab Simulink/SimPower Result on network system data (PSS/E - Matlab Simulink/SimPower 간 순시치 시뮬레이션 비교에 관한 연구)

  • Yoo, Yeuntae;Kim, Kisuk;Lee, Changun;Jang, Gilsoo
    • Proceedings of the KIEE Conference
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    • 2015.07a
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    • pp.249-250
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    • 2015
  • Technological advance of power elcetronic devices using semiconductor switches in last several decades, invoke the increase of switching devices' penetration in the system like STATCOM or HVDC and also, increase the difficulty to adjust switching characteristics in the virtual simulating configuration, which are not capable of reflect the detailed phenomena. To investigate harmful effect of switching devices into the grid, detailed modeling of power electronic devices are necessary, and the first step for entire grid modelling is simulate power system in time domain model. In this paper, simple two bus system with synchronous generator and infinite bus on the other side has been compromised in two simulation environment, using PSS/E and Matlab/Simulink. Comparing the result of two simulation result will give answers to the fundamental difference between two type of simulation environment.

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Do Quality-Focused Retailer Brand Types Contribute to Building Store Loyalty in Korea?

  • Chung, Lak-Chae;Cho, Young-Sang
    • Journal of Distribution Science
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    • v.11 no.9
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    • pp.5-15
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    • 2013
  • Purpose - The research aim is to shed empirical light on whether quality-focused retailer brands such as Premium brand of Tesco Korea, Prime of Lotte Mart, and Best of E-Mart in the grocery market, make a contribution to developing store loyalty in the Korean market particularly. Research design, data, methodology - After developing sixconstructs, such as higher quality, stock availability, price levels, national brands, retailer brand attitudes, and store loyalty, the authors adopted exploratory factor analysis, confirmatory factor analysis, chi-square test and structural equation modelling as a research technique. Results - It was found that higher quality strongly influences the retailer brand attitude formation, and that retailer brand customers were sensitive to price levels. Buyers are, nevertheless, relatively less aware of price levels, when purchasing quality-oriented retailer brand types. Conclusions - The research implied that quality-oriented retailer brand types make a significant contribution to retailer brands attitude formation, and further, building store loyalty.

Development of a S/W for a Structural Analysis of Machine tools utilizing database (데이터베이스를 활용한 공작기계의 구조해석 프로그램 개발)

  • Shin, Jeong-Ho;Kwak, Byung-Man
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.446-451
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    • 2000
  • In this paper, a S/W system for a structural analysis of machine tools has been suggested. The system is so designed to reduce manual interfacing effort. An object-oriented language is used for making a graphic user interface. In this system parametric modelling technique is applied to construct a FE model without much user intervention. The FE model is automatically updated when the design parameters are changed by user. Not only single FE analysis but also a trade-off analysis for calculating the sensitivity information of design variables is possible using this system. All data generated by this system are saved in the database. So it possible to retrieve the result later without another analysis. It is found that the design time can be reduced and unnecessary operation avoided using this system.

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Evaluation of turbulence models in rough-wall boundary layers for hydroelectric applications

  • Dutta, Rabijit;Nicolle, Jonathan;Giroux, Anne-Marie;Piomelli, Ugo
    • International Journal of Fluid Machinery and Systems
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    • v.10 no.3
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    • pp.227-239
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    • 2017
  • The accuracy of turbulence models for the Reynolds-Averaged Navier-Stokes (RANS) equations in rough-wall flows is evaluated using data from large-eddy simulations (LES) of boundary layers with favourable and adverse pressure gradients. Some features of the flow (such as flow reversal in the roughness sublayer) cannot be captured accurately by any model, due to the fundamental model formulation. In mild pressure gradients most RANS models are sufficiently accurate for engineering applications, but if strong favourable or adverse pressure gradients are applied (especially those leading to separation) the model performance rapidly degrades.

Modelling and Test of Down-the-Hole Hammer (다운더홀(DTH) 해머의 모델링 및 실험)

  • Hwang, U.K.
    • Journal of Drive and Control
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    • v.12 no.2
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    • pp.34-38
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    • 2015
  • Research and development of mineral resource related products has progressed with the increased need to develop mineral resources. The DTH hammer is one a resultant product. However, due to particular work conditions of underground drilling, it is difficult to obtain direct data on the DTH Hammer. A DTH drill rig requires a lot of money and time for actual testing. This thesis aimed to resolve this problem by using CAE. First, the structure of the DTH hammer and the movement was analyzed. Next, a standard model based on simulation was proposed and then experimentation and comparison verification was conducted. In addition, the verified models were applied to products of various sizes, and the models used in simulation were compared by conducting field tests.