• 한국음향학회:학술대회논문집
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• 한국음향학회 2000년도 하계학술발표대회 논문집 제19권 1호
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• pp.291-294
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• 2000

가속 주행하는 차량의 소음을 줄이기 위해서는 각 소음원의 기여도를 파악하는 것이 필요하다. 본 논문에서는, 가속 주행하는 차량의 배기 토출 소음을 ISO362에서 규정한 음압 측정 지점에서 예측하기 위하여, 시간 영역에서 근접장 배기 토출 소음을 예측할 수 있는 시뮬레이션 프로그램 'WAVE'와 움직이는 음원의 방사 모델을 이용하였다. 가속 주행중 차량의 소음원에 의한 음파의 전달은 도플러효과와 시간 지연이 발생하며, 이를 고려하여 정지된 지점에서의 소음레벨을 예측하였으며, 배기 토출 소음의 예측을 통하여 가속주행소음에 대한 기여도와 그 소음 특성을 파악할 수 있다.

• 한국인터넷방송통신학회논문지
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• 제13권1호
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• pp.229-234
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• 2013

스마트폰의 보급과 위치 기반 서비스의 활성화로 스마트폰을 기반으로 하는 위치정보 서비스의 필요성과 중요성이 매우 중요해지고 있다. 그러나 기존의 방법들은 경제성이나 편의성, 정확도의 부족으로 실용화가 어려운 상황이며, 무선랜의 신호세기를 이용한 방법은 정확도가 떨어지는 문제가 있다. 본 논문에서는 스마트폰의 음향신호와 블루투스 통신 방식을 이용한 상대위치 인식 기술에 대한 기술적 배경과 구현 기술 및 측정 결과에 대해 기술하였다. 이 기술은 저렴한 구현 비용의 단일 장치로 스마트폰의 정밀한 측위가 가능하며, 특히 실내에서의 위치기반 지능화 서비스에 적합하다.

• 컴퓨터교육학회논문지
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• 제9권3호
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• pp.67-74
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• 2006

본 연구에서는 학습자가 특정 e-러닝 프로그램을 선호하는데 영향을 미치는 다양한 요인들을 탐색해 보았다. 선호도에 영향을 미치는 다양한 변인들을 열거하고 그러한 변인들을 상관 정도에 따라 공통요인을 추출하는 탐색적 요인분석(exploratory factor analysis)를 실시하였다. 분석 결과, 학습자들이 특정한 형태의 e-러닝 프로그램을 선호하게 되는 주된 요인들은 e-러닝 프로그램의 설계방식(1 요인), e-러닝 프로그램 활용목적(2 요인), 사회문화적 쟁점(3요인), 인구학적 요소(4 요인), 조직의 요구(5요인), e-러닝 프로그램 활용결과(6요인), e-러닝 프로그램 운영관리(7 요인), e-러닝 프로그램의 기술적 환경(8 요인)으로 나타났다.

• Geomechanics and Engineering
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• 제14권6호
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• pp.553-562
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• 2018

Road construction is becoming increasingly important in marine and desert areas due to population growth and economic development. However, the load carrying capacity of pavement is of gear concern to design and geotechnical engineers because of the poor engineering properties of the soils in these areas. Therefore, stabilization of the soils is regarded as an important issue. Besides, due to the fuels combustion and carbonate decomposition, cement industry generates around 5% of global $CO_2$ emission. Thus, using bentonite as a natural pozzolan in soil stabilization is more eco-friendly than using cement. The aim of this research is to experimentally study of the stabilized marine and desert sands using deep mixing method by ordinary Portland cement and sodium bentonite. Different partial percentages of cement along with different weight percentages of sodium bentonite were added to the sands. Unconfined compression test (UCS), Energy Dispersive X-ray (EDX), and Scanning Electron Microscope (SEM) were conducted on the specimens. Moreover, a mathematical model was developed for predicting the strength of the treated soils.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권2호
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• pp.728-741
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• 2015

Stereo vision has become an important technical issue in the field of 3D imaging, machine vision, robotics, image analysis, and so on. The depth map extraction from stereo video is a key technology of stereoscopic 3D video requiring stereo correspondence algorithms. This is the matching process of the similarity measure for each disparity value, followed by an aggregation and optimization step. Since it requires a lot of computational power, there are significant speed-performance advantages when exploiting parallel processing available on processors. In this situation, multi-core CPU may allow many parallel programming technologies to be realized in users computing devices. This paper proposes parallel implementations for calculating disparity map using a shared memory programming and exploiting the streaming SIMD extension technology. By doing so, we can take advantage both of the hardware and software features of multi-core processor. For the performance evaluation, we implemented a parallel SAD algorithm with OpenMP and SSE2. Their processing speeds are compared with non parallel version on stereoscopic streaming video. The experimental results show that both technologies have a significant effect on the performance and achieve great improvements on processing speed.

• ETRI Journal
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• 제39권4호
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• pp.480-492
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• 2017

A holographic display based on a viewing window enables the converging of a reconstruction wave into a viewing window by means of an optical system. Accordingly, a user can observe a reconstructed hologram image, even with a small diffraction angle. It is very difficult to manufacture an optical system with no aberrations; thus, it is inevitable that a certain amount of wave aberrations will exist. A viewing-window-based holographic display, therefore, always includes distortions in an image reconstructed from a hologram pattern. Compensating the distortions of a reconstructed image is a very important technical issue because it can dramatically improve the performance when reconstructing a digital three-dimensional content image from a hologram pattern. We therefore propose a method for suppressing image distortion by measuring and compensating the wave aberration calculated from a Zernike polynomial, which can represent arbitrary wave aberrations. Through our experimental configuration using only numerical calculations, our proposed method decreased the reconstructed image distortion by more than 28%.

• Genomics & Informatics
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• 제18권2호
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• pp.16.1-16.5
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• 2020

There has been a dramatic increase in the popularity of utilizing social media data for research purposes within the biomedical community. In PubMed alone, there have been nearly 2,500 publication entries since 2014 that deal with analyzing social media data from Twitter and Reddit. However, the vast majority of those works do not share their code or data for replicating their studies. With minimal exceptions, the few that do, place the burden on the researcher to figure out how to fetch the data, how to best format their data, and how to create automatic and manual annotations on the acquired data. In order to address this pressing issue, we introduce the Social Media Mining Toolkit (SMMT), a suite of tools aimed to encapsulate the cumbersome details of acquiring, preprocessing, annotating and standardizing social media data. The purpose of our toolkit is for researchers to focus on answering research questions, and not the technical aspects of using social media data. By using a standard toolkit, researchers will be able to acquire, use, and release data in a consistent way that is transparent for everybody using the toolkit, hence, simplifying research reproducibility and accessibility in the social media domain.

• The Journal of Asian Finance, Economics and Business
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• 제6권3호
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• pp.141-149
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• 2019

The paper proposes a knowledge innovation performance model by the dynamic data envelopment analysis with slacks-based measure approach for evaluating the effectiveness of 30 regional knowledge innovation activities in China from 2010 to 2016. In recent years, China has paid more attention to knowledge innovation activities, as central and local governments have pushed on with their innovation projects by lots of investment whatever the difficulties may be. Decision-maker is usually interested in judge its knowledge innovation performance relative to target benchmark by exploring whether one provincial administration region performs better among others and/or if the growth of economy will be benefited greatly by the knowledge innovation activities. To acquire the managerial insight about this issue from a comprehensively designed performance evaluation model, knowledge innovation activity is conceptualized as an intertemporal production process. Invention patent and regional gross product are imposed on desirable outputs, highlighting the need for knowledge economy. The empirical result shows that knowledge innovation has a positive effect on economic development. At the same time, decision-maker should be interest in the economic effect of patents' type and quality. The government should then encourage new technical applications with greater commercial value from a market-oriented perspective, in order to benefit the most from the innovation process in the short-run.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.215-217
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• 2004

In wireless sensor networks, fair allocation of bandwidth among different nodes is one of the critical problems that effects the serviceability of the entire system. Fair bandwidth allocation mechanisms, like fair queuing, usually need to maintain state, manage buffers, and perform packet scheduling on a per flow basis, and this complexity may prevent them from being cost-effectively implemented and widely deployed. It is a very important and difficult technical issue to provide packet scheduling architecture for fairness in wireless sensor networks. In this paper, we propose an packet scheduling architecture for sensor node, called FISN (Fairness Improvement Sensor Network), that significantly reduces this implementation complexity yet still achieves approximately fair bandwidth allocations. Sensor node for sensing estimate the incoming rate of each sensor device and insert a label into each transmission packet header based on this estimate. Sensor node for forwarding maintain no per flow state; they use FIFO packet scheduling augmented by a probabilistic dropping algorithm that uses the packet labels and an estimate of the aggregate traffic at the gathering node. We present the detailed design, implementation, and evaluation of FISN using simulation. We discuss the fairness improvement and practical engineering challenges of implementing FISN in an experimental sensor network test bed based on ns-2.

• 한국정보시스템학회지:정보시스템연구
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• 제15권3호
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• pp.131-157
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• 2006

A lack of trust in the technical and institutional environments surrounding the web can hinder e-commerce adoption, because Internet social cues are minimal and trust is difficult th establish. Web vendors must act purposefully to overcome consumer perceptions of uncertainty and risk by building trust-both in their own web sites and in the broader Internet environments. Trust makes consumers comfortable by sharing personal information making purchases, and acting on web vendor advice-behaviors essential to wide-spread adoption of e-commerce. Understanding the nature and antecedents of trust is, therefore, a major issue for both Internet researchers and practitioners. Prior research on e-commerce trust has used diverse, incomplete, and inconsistent definitions of trust therefore, making it difficult to compare results across studies. This study tried to and the empirical relationships among the trust-related factors on the usage of Internet shooing mall. The model includes five high-level constructs-disposition to trust institution-based trust trusting beliefs, trusting intention and environmental factors. The results showed that the disposition to trust and the environmental factors had a significant effect on the web site trust however, their effect was not consistent Moreover, the model suggested in this study need to be extended including with the more sociological factors and results in this study required to be verified with those extended model.