• Title/Summary/Keyword: model reduction technique

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A Phase-Domain Equivalent Representation for Electromagnetic Transients Studies (전력계통 과도현상 해석을 위한 상영역에서의 등가축약 기법)

  • Jung, B.T.;Kim, S.H.;Heo, S.I.;Ahn, B.S.;Hong, J.H.
    • Proceedings of the KIEE Conference
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    • 1996.07b
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    • pp.731-733
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    • 1996
  • In this paper, a new time-domain reduction method for unbalanced 3 phase power systems will be represented. The impulse response of the system is used to identify a discrete-time equivalent filter model. The model is formulated directly in the phase domain. Each phase has a self-mode equivalent model and two mutual-mode equivalent models. The equivalent model is determined by the transfer function identification technique based on the Prony analysis. The model is implemented in EMTDC and tested with an unbalanced 3 phase network. The result of test showed that the equivalent model is accurate.

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Active Control of Sound in a Duct System by Back Propagation Algorithm (역전파 알고리즘에 의한 덕트내 소음의 능동제어)

  • Shin, Joon;Kim, Heung-Seob;Oh, Jae-Eung
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.9
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    • pp.2265-2271
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    • 1994
  • With the improvement of standard of living, requirement for comfortable and quiet environment has been increased and, therefore, there has been a many researches for active noise reduction to overcome the limit of passive control method. In this study, active noise control is performed in a duct system using intelligent control technique which needs not decide the coefficients of high order filter and the mathematical modeling of a system. Back propagation algorithm is applied as an intelligent control technique and control system is organized to exclude the error microphone and high speed operational device which are indispensable for conventional active noise control techniques. Furthermore, learning is performed by organizing acoustic feedback model, and the effect of the proposed control technique is verified via computer simulation and experiment of active noise control in a duct system.

A Study on All Ceramic Crown Manufactured Using Gold Plating Upon Refractory Cast Die (매몰재 Die 위에 금도금을 이용한 전부 도재관 제작에 관한 연구)

  • Shin, Moo-Hak;Kim, Yeoun-Soo;Chung, Hee-Sun
    • Journal of Technologic Dentistry
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    • v.22 no.1
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    • pp.49-55
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    • 2000
  • In manufacturing the all-ceramic crown whick look close to natural teeth, the effectiveness of the improved technique is expectected the technique of the heat treatment of gold plating coating die was experimented of a refractory cast model. The following results were obtainde 1. An advantage of build up on east die with out manufacturing veneer, crown, core, or masking(reduction of technical process, and retrenchment of time and money) 2. Esthetically more close to natural teeth than other technique 3. Easy to remove a refractors cast die 4. In manufacturing ceramo-metal crown the enomous effectiveness was obtainde on applying in the areas of cervical margin, the metal surface, and in the treatment of pinhole.

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An Efficient Global Motion Estimation based on Robust Estimator

  • Joo, Jae-Hwan;Choe, Yoon-Sik
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2009.01a
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    • pp.408-412
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    • 2009
  • In this paper, a new efficient algorithm for global motion estimation is proposed. This algorithm uses a previous 4-parameter model based global motion estimation algorithm and M-estimator for improving the accuracy and robustness of the estimate. The first algorithm uses the block based motion vector fields and which generates a coarse global motion parameters. And second algorithm is M-estimator technique for getting precise global motion parameters. This technique does not increase the computational complexity significantly, while providing good results in terms of estimation accuracy. In this work, an initial estimation for the global motion parameters is obtained using simple 4-parameter global motion estimation approach. The parameters are then refined using M-estimator technique. This combined algorithm shows significant reduction in mean compensation error and shows performance improvement over simple 4-parameter global motion estimation approach.

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(Signal Integrity Verification of a General VLSI Interconnects using Virtual-Straight Line Model) (가상 직선 모델을 사용한 일반적 VLSI 배선의 신호의 무결성 검증)

  • Jin, U-Jin;Eo, Yeong-Seon;Sim, Jong-In
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.39 no.2
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    • pp.146-156
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    • 2002
  • In this paper, a new virtual-straight line parameter determination methodology and fast time domain simulation technique for non-uniform interconnects are presented and verified. Time domain signal response of interconnects circuit considering the characteristic of non-linear transistor is performed by using model order reduction method. Since model order reduction method is peformed by using per unit length parameters, virtual- straight line parameters for non-uniform interconnects are determined. Its method is integrated into Berkeley SPICE and shown that time domain signal responses using proposed method have a good agreement with the results of conventional circuit simulator HSPICE. The proposed method can be efficiently employed in the high-performance VLSI circuit design since it can provide a fast and accurate time domain signal response of complicated multi - layer interconnects.

Scalable Hybrid Recommender System with Temporal Information (시간 정보를 이용한 확장성 있는 하이브리드 Recommender 시스템)

  • Ullah, Farman;Sarwar, Ghulam;Kim, Jae-Woo;Moon, Kyeong-Deok;Kim, Jin-Tae;Lee, Sung-Chang
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.12 no.2
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    • pp.61-68
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    • 2012
  • Recommender Systems have gained much popularity among researchers and is applied in a number of applications. The exponential growth of users and products poses some key challenges for recommender systems. Recommender Systems mostly suffer from scalability and accuracy. The accuracy of Recommender system is somehow inversely proportional to its scalability. In this paper we proposed a Context Aware Hybrid Recommender System using matrix reduction for Hybrid model and clustering technique for predication of item features. In our approach we used user item-feature rating, User Demographic information and context information i.e. specific time and day to improve scalability and accuracy. Our Algorithm produce better results because we reduce the dimension of items features matrix by using different reduction techniques and use user demographic information, construct context aware hybrid user model, cluster the similar user offline, find the nearest neighbors, predict the item features and recommend the Top N- items.

Advanced Structural Silicone Glazing

  • Kimberlain, Jon;Carbary, Larry;Clift, Charles D.;Hutley, Peter
    • International Journal of High-Rise Buildings
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    • v.2 no.4
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    • pp.345-354
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    • 2013
  • This paper presents an advanced engineering technique using finite element analysis to improve structural silicone glazing (SSG) design in high-performance curtain wall systems for building facade. High wind pressures often result in bulky SSG aluminum extrusion profile dimensions. Architectural desire for aesthetically slender curtain wall sight-lines and reduction in aluminum usage led to optimization of structural silicone bite geometry for improved stress distribution through use of finite element analysis of the hyperelastic silicone models. This advanced design technique compared to traditional SSG design highlights differences in stress distribution contours in the silicone sealant. Simplified structural engineering per the traditional SSG design method lacks accurate forecasting of material and stress optimization, as shown in the advanced analysis and design. Full scale physical specimens were tested to verify design capacity in addition to correlate physical test results with the theoretical simulation to provide confidence of the model. This design technique will introduce significant engineering advancement to the curtain wall industry and building facade.

A Study on Improving the Accuracy of Finite Element Modeling Using System Identification Technique (S. I. 기법을 이용한 유한요소모델의 신뢰도 제고에 관한 연구)

  • 양경택
    • Computational Structural Engineering
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    • v.10 no.2
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    • pp.149-160
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    • 1997
  • Mechanical structures are composed of substructures connected by joints and boundary elements. While the finite element representation of plain substructures is well developed and reliable, joints have a lot of uncertainties in being accurately modelled and affect dynamic behavior of a total system. In order to improve the accuracy of a finite element model, a new method is proposed, in which reduced finite element model is combined with a system identification technique. After substructures except joints are modelled with finite element method and joint properties are represented by parameter states, non-linear state equation is derived in which parameter states are multiplied by physical states such as displacements and velocities. So the joint parameter identification is transformed into non-linear state estimation problem. The methods are tested and discussed numerically and the feasibility for physical application has been demonstrated through two example structures.

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Small scale experimental testing to verify the effectiveness of the base isolation and tuned mass dampers combined control strategy

  • Petti, Luigi;Giannattasio, Giovanni;De Iuliis, Massimiliano;Palazzo, Bruno
    • Smart Structures and Systems
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    • v.6 no.1
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    • pp.57-72
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    • 2010
  • This paper presents the most significant results obtained within a broad-ranging experimental program aiming to evaluate both the effectiveness and the robustness of a Base Isolation (BIS) and a Tuned Mass Damper (TMD) combined control strategy (BI & TMD). Following a brief description of the experimental model set-up and the adopted kinematic scaling technique, this paper describes the identification procedures carried out to characterize the system''s model. The dynamic response of a small-scale model to recorded earthquake excitations, which has been scaled by using the Buckingham pi-theorem, are later presented and discussed. Finally, the effectiveness and robustness of the combined control strategy is evaluated by comparing the model's dynamic response. In particular, reduction in relative displacements and absolute accelerations due to the application of different mass damping systems is investigated.

Injection of Cultural-based Subjects into Stable Diffusion Image Generative Model

  • Amirah Alharbi;Reem Alluhibi;Maryam Saif;Nada Altalhi;Yara Alharthi
    • International Journal of Computer Science & Network Security
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    • v.24 no.2
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    • pp.1-14
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    • 2024
  • While text-to-image models have made remarkable progress in image synthesis, certain models, particularly generative diffusion models, have exhibited a noticeable bias to- wards generating images related to the culture of some developing countries. This paper introduces an empirical investigation aimed at mitigating the bias of image generative model. We achieve this by incorporating symbols representing Saudi culture into a stable diffusion model using the Dreambooth technique. CLIP score metric is used to assess the outcomes in this study. This paper also explores the impact of varying parameters for instance the quantity of training images and the learning rate. The findings reveal a substantial reduction in bias-related concerns and propose an innovative metric for evaluating cultural relevance.