• 한국멀티미디어학회논문지
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• 제23권1호
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• pp.31-42
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• 2020

During the 4th Industrial Revolution, service platforms utilizing diverse contents are emerging, and research on recommended systems that can be customized to users to provide quality service is being conducted. hybrid recommendation systems that provide high accuracy recommendations are being researched in various domains, and various filtering techniques, machine learning, and deep learning are being applied to recommended systems. However, in a recommended service environment where data must be analyzed and processed real time, the accuracy of the recommendation is important, but the computational speed is also very important. Due to high level of model complexity, a hybrid recommendation system or a Deep Learning-based recommendation system takes a long time to calculate. In this paper, a Cascade-hybrid recommended algorithm is proposed that can reduce the computational time while maintaining the accuracy of the recommendation. The proposed algorithm was designed to reduce the complexity of the model and minimize the computational speed while processing sequentially, rather than using existing weights or using a hybrid recommendation technique handled in parallel. Therefore, through the algorithms in this paper, contents can be analyzed and recommended effectively and real time through services such as SNS environments or shared economy platforms.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 추계종합학술대회
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• pp.332-335
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• 2007

본 논문에서는 버퍼를 이용한 가변적인 트래픽을 제어에서 영상의 품질 변화를 최소화 하는 방법을 제안한다. 제안하는 알고리즘은 반복적인 최적화 방법을 사용하지 않고 프레임 레이어에서 전송률을 제어하는 방법으로 영상 프레임간의 왜곡의 변화를 최소화한다. 그리고 버퍼의 정보를 비트율에 효과적으로 반영하기 위하여 제어 시스템에서 많이 사용되는 PID 제어를 하였다. PID 제어는 많은 계산량을 필요로 하지 않기 때문에 제안하는 알고리즘은 낮은 계산량을 필요로 하는 실시간 영상코덱에 적당한 알고리즘이다. 제안하는 알고리즘과 기존의 알고리즘간의 비교 실험은 제안하는 알고리즘이 PSNR 성능에서 기존의 알고리즘 보다 우수함을 보여준다.

• 한국정보통신학회논문지
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• 제11권11호
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• pp.2009-2014
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• 2007

본 논문에서는 버퍼를 이용한 가변적인 트래픽을 제어에서 영상의 품질 변화를 최소화 하는 방법을 제안한다. 제안하는 알고리즘은 반복적인 최적화 방법을 사용하지 않고 프레임 레이어에서 전송률을 제어하는 방법으로 영상 프레임간의 왜곡의 변화를 최소화한다. 그리고 버퍼의 정보를 비트율에 효과적으로 반영 하기 위하여 제어 시스템에서 많이 사용되는 PID 제어를 하였다. PID 제어는 많은 계산량을 필요로 하지 않기 때문에 제안하는 알고리즘은 낮은 계산량을 필요로 하는 실시간 영상 코덱에 적당한 알고리즘이다. 제안하는 알고리즘과 기존의 알고리즘간의 비교 실험은 제안하는 알고리즘이 PSNR 성능에서 기존의 알고리즘 보다 우수함을 보여준다.

• Advances in Computational Design
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• 제4권3호
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• pp.307-326
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• 2019

A low computational cost semi-analytical method is developed, based on eigenfunction expansion, to study the vibration of rectangular plates subjected to a series of moving sprung masses, representing a bridge deck under multiple vehicle or train moving loads. The dynamic effects of the suspension system are taken into account by using flexible connections between the moving masses and the base structure. The accuracy of the proposed method in predicting the dynamic response of a rectangular plate subjected to a series of moving sprung masses is demonstrated compared to the conventional rigid moving mass models. It is shown that the proposed method can considerably improve the computational efficiency of the conventional methods by eliminating a large number of time-varying components in the coupled Ordinary Differential Equations (ODEs) matrices. The dynamic behaviour of the system is then investigated by performing a comprehensive parametric study on the Dynamic Amplification Factor (DAF) of the moving loads using different design parameters. The results indicate that ignoring the flexibility of the suspension system in both moving force and moving mass models may lead to substantially underestimated DAF predictions and therefore unsafe design solutions. This highlights the significance of taking into account the stiffness of the suspension system for accurate estimation of the plate maximum dynamic response in practical applications.

• 한국통신학회논문지
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• 제31권8C호
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• pp.801-805
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• 2006

A normalization approach to coefficient adaptation in the escalator(ESC) filter structure that conventionally employs least mean square(LMS) algorithm is introduced. Using Taylor's expansion of the local error signal, a normalized form of the ESC-LMS algorithm is derived. Compared with the computational complexity of the conventional ESC-LMS algorithm employs input power estimation for time-varying convergence coefficient using a single-pole low-pass filter, the computational complexity of the proposed method can be reduced by 50% without performance degradation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.80.2-80
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• 2002

The problem of sound source localization is to determine the position of sound sources using the measurement of the acoustic signals received by microphones. To develop a good sound source localization system which is applicable to a mobile platform such as robots, a time delay estimator with low computational complexity and robustness to background noise or reverberations is necessary. In this paper, an explicit adaptive time delay estimation method for a sound source localization system is proposed. Proposed explicit adaptive time estimation algorithm employs direct adaptation of the delay parameter using a transform-based optimization technique, rather than...

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 심포지엄 논문집 정보 및 제어부문
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• pp.3-6
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• 2004

In this paper, the problem of identifying a time-varying nonlinear system in an adaptive way was considered, whereby the time-varying second-order Volterra series was employed to model the system and the filtered weighted least squares (FWLS) algorithm was utilized for the fast parameter tracking capability with low computational burden. Finally, the performance of the proposed approach was demonstrated by providing some computer simulation results.

• 대한전기학회논문지:시스템및제어부문D
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• 제51권2호
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• pp.86-88
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• 2002

An estimation method for the characteristic parameters in the low frequency signal is proposed in this paper. A low frequency signal is assumed to be modulated or distorted by high frequency terms. The algorithm proposed in this paper is designed to select set of local maximums in a successive manner, hence it is denoted as the iterative peak picking(IPP) algorithm. The IPP algorithm is operating in the time domain and is using only the comparison operation between two neighboring samples. Therefore, its computational complexity is very low and the delay caused by the computation is negligible, which make the real-time operation possible with economic hardware. The proposed algorithm is verified on the pitch estimation of speech signal and blood pulse estimation.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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• pp.652-659
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• 2005

Even in moderate to low seismic regions like Korean peninsular where wind loading usually governs the structural design of a tall building, the probable structural impact of the design basis earthquake or the maximum credible earthquake on the selected structural system should be considered at least in finalizing the design. In this study, by using response spectrum analysis and linear time history analysis method, seismic performance evaluation was conducted for wind-designed concentrically braced steel highrise buildings. Both spectrum-compatible artificial accelerograms and recorded accelerograms were used as input ground motions for the time history analysis. The analysis results showed that wind-designed concentrically braced steel highrise buildings possess significantly increased elastic seismic capacity due to the system overstrength resulting from the wind-serviceability criterion and the width-to-thickness ratio limits on steel members. Time history analysis results generally tended to underestimate the seismic response as compared to those of response spectrum analysis.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2006년도 PARALLEL CFD 2006
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• pp.94-99
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• 2006

As part of a Department of Defense Grand Challenge Project, advanced high performance computing (HPC) time-accurate computational fluid dynamics (CFD) techniques have been developed and applied to a new area of aerodynamic research on microjets for control of small and medium caliber projectiles. This paper describes a computational study undertaken to determine the aerodynamic effect of flow control in the afterbody regions of spin-stabilyzed projectiles at subsonic and low transonic speeds using an advanced scalable unstructured flow solver in various parallel computers such as the IBM SP4 and Linux Cluster. High efficiency is achieved for both steady and time-accurate unsteady flow field simulations using advanced scalable Navier-Stokes computational techniques. Results relating to the code's portability and its performance on the Linux clusters are also addressed. Numerical simulations with the unsteady microjets show the jets to substantially alter the flow field both near the jet and the base region of the projectile that in turn affects the forces and moments even at zero degree angle of attack. The results have shown the potential of HPC CFD simulations on parallel machines to provide to provide insight into the jet interaction flow fields leading to improve designs.