논단 2-전기방식 기술

김대경,Kim, Dae-Gyeong 한국전기산업진흥회 1996 電氣産業 Vol.7 No.4

후처리를 이용한 음질 개선 시스템의 성능 향상

김대경,우종식 동의공업대학 1999 論文集 Vol.25 No.1

The speech enhancement has gained an increasing interest in recent years. This is mainly due to the driving forces in the area of mobile communications, where speech enhancement algorithms could be integrated in hands-free telephony. The availability of powerful digital signal processors is also supporting these activities. This paper focuses on the spectral subtraction method that is relatively inexpensive, in terms of computational complexity. In the spectral subtraction method, the noise-suppressed speech spectrum is obtained by subtracting an estimated noise spectrum from the noisy speech spectrum. The noise spectrum is estimated, is updated, from the periods when the signal is absent and only the noise is present. The assumption is that the noise is a stationary or a slowly varying process, and that the noise spectrum does not change significantly in between the update periods. Single channel spectral subtraction algorithm is characterized by a tradeoff between the amount of noise reduction, the speech distortion. and the level of musical residual noise The residual noise is always remained because the estimated noise spectrum is not exactly matched to true nose spectrum. ESS(extended spectral subtraction) algorithm overcomes the typical disadvantage of one channel noise suppression algorithms-the impossibility of noise estimation during speech sequence. The noise can be successively updated even during the speech sequences and that is why there is no need of the voice activity detection. However the residual noise becomes more noticeable as the SNR decrease Post-processing method is combined with the ESS algorithm for speech enhancement. There is no need of voice activity detection because the noise can be successively updated even during the speech using Wiener filter. We have compared the proposed algorithm with other spectral subtraction algorithm. Objective and subjective evaluation of the proposed system is performed with car noise. The subjective listening tests confirm that the enhanced speech is more pleasant to a human listener.

배뇨반사에서 퓨린수용체의 생리적, 병태생리적 기능

김대경 대한배뇨장애요실금학회 2008 International Neurourology Journal Vol.12 No.2

Purinergic neurotransmission has been regarded as major component of non-adrenergic, noncholinergic (NANC) contraction in detrusor smooth muscle. Although in normal human detrusor,this contraction seems to be small, the importance of the NANC component for detrusor contraction in disease conditions such as detrusor overactivity remains to be established. Based on many evidences for purinergic contributions in lower urinary tract, ATP and purinoceptors has been suggested to be involved in both efferent and afferent mechanism in voiding reflex. ATP signaling via P2X1 receptors plays an important role in efferent neural control of urinary bladder function, although to varying degrees across species from experimental animals to men. The efferent function of purinoceptors may be enhanced in detrusor overactivity and aging. ATP also suggested being involved in mechanosensory transmission, via activation of P2X3 and P2X2/3 receptors on sensory afferent nerves. The afferent function of purinoceptors may be related with pathophysiology of overactive bladder or interstitial cystitis, mediating bladder hyperexicitability. These results suggest that the selective antagonists for the purinoceptors may offer better relief of sensory and motor symptoms for overactive bladder or interstitial cystitis patients in the future. (J Korean Continence Soc 2008;12:93-8)

창조경제를 위한 스마트그리드 로드맵

김대경 대한전기학회 2013 대한전기학회 학술대회 논문집 Vol.2013 No.5

보청기에서 적응궤환제거의 성능 향상

김대경,허종,박장식,손경식,Kim, Dae-Kyung,Hur, Jong,Park, Jang-Sik,Son, Kyung-Sik 한국음향학회 1999 韓國音響學會誌 Vol.18 No.4

본 논문에서는 보청기에서의 적응궤환 제거 성능을 개선하기 위한 방법들을 제안하였다. 첫번째 방법은 순시 경사치를 모니터링하여 최적해를 추적해 가는 것으로 직교원리를 이용한 음향학적 궤환제거 방법이고 다른 하나는 본 실험실에서 제안된 적응 알고리즘인 보상기를 가진 적응알고리즘을 이용한 방법이다. 다양한 시뮬레이션 조건하에서 본 논문에서 제안된 적응 궤환제거 방법이 Greenberg가 제안한 합-방식(Sum-method) 최소자승오차 알고리즘 보다 시스템 부정합, 신호대 잡음비(SNR: Signal-to-Noise Ratio) 및 세그멘트 SNR에서 훨씬 좋은 성능을 나타내었다. 또한 적응 궤환제거에 있어서 직교원리를 이용한 방법은 시뮬레이션에서 보상기를 가진 적응알고리즘을 이용한 방법과 유사한 성능을 나타내었다. In this paper, two methods were proposed to improve the performance of adaptive feedback cancellation in hearing aids. One is “Orthogonality principle acoustic feedback cancellation method(Orthogonality principle method)” to track optimal solution with monitoring the instantaneous gradient, the other is a method using the CLMS algorithm(CLMS method). In many simulation conditions, adaptive feedback cancellation method proposed in this paper was much better than Greenberg method by Sum-method LMS algorithm which is known the most excellent method by now in case of system mismatch, SNR and segmental SMR. Also. Orthogonality principle method is as good as CLMS method in terms of adaptive feedback cancellation in many simulation conditions.

Die Untersuchung über das Offenkundigkeitsprinzip und dessen Ausnahme in der Stellvertretungshandlung nach dem BGB

김대경 아주대학교 법학연구소 2014 아주법학 Vol.8 No.2

This paper consider about the principles and exceptions of named principal in the German Civil Law with respect to the attitude of theory and case law. The named principal in the acts of agent aims to clearly deal with the legal relationship among the contract parties. Unlike the German Civil Law takes the named principal in case of the civil and commercial agency, but korea civil code is applied only for civil agency. This difference is based on the reasons as follows, the effect of promoting the safety, simplicity and immediacy of the commercial-transaction. The clue of the discussion in this paper is that there are some needs to recognize that is applied in case of civil law. The German Civil Code Article 164 stipulates the principles of named principal and there are enough ways that will be able to recognize the action for others in light of various factors, as well as explicit. In particular, agency intention plays an important role to determin, whether the cancel of a contract due to fall into the error is possible. Otherwise, the effects of transaction without the named principal are directly belonged to the angency. Basically the Geman Civil Code adhere to the named principal in the acts of agent, but there are some exceptions, that is the theory of Acts-belonging. According the above theory, in the following cases, for example, transactions that do not focus on the personality of the other acts, such as cash transactions of everyday life, relationship bonds, a real right relationships, further actions based on the identity relations. It is thought that the problems related to the principles and exceptions of named principal in korea civil law can be overcome through teleological interpretation in a range that does not undermine the institutional significance and function. Bei dieser Arbeit geht es um die dogmatische Untersuchung über das Offenkundigkeitsprinzip und dessen Ausnahme im BGB. Hier ist vor allem darüber in Betracht zu ziehen, wie das Offenkundigkeitsprinzip im BGB funktioniert ist und in welchen Fällen bzw. Anwendungsbereichen dessen Ausnahme zugelassen und erweitert ist. Das Stellvertretungsrecht geht vom Offenkundigkeitsgrundsatz aus. Das Offenkundigkeitsprinzip dient grundsätzlich nicht nur dem Schutz des Vertragspartners, sondern auch daneben dem Schutz der Rechtsklarheit und des allgemeinen Rechtsverkehrs. Neben der ausdrücklichen oder konkludenten Stellvertretungserklärung ist ein entsprechender Vertretungswille des Vertreters für die Bejahung des Tatbestandmerkmals des Handelns im fremden Namen erforderlich. „Das offene Geschäft für den, den es angeht“ ist nach dem Prinzip der Vertragsfreiheit und dem Grundsatz der Gestaltungsfreiheit grundsätzlich zulässig. Ferner ist das vielmehr fraglich, ob das versteckte Geschäft für den, den es angeht zulässig ist. Zwar gibt es sehr unterschiedliche und umstrittene Auffassungen, aber nach den herrschenden Auffassungen ist das auch unter bestimmten Voraussetzungen zulässig. Auch die für den Eigentumserwerb erforderliche Übergabe an den Erwerber kann auf unterschiedliche Art und Weise erfolgen. So bei Besitzerwerb erwirbt der verdeckt gebliebene Vertretene das Eigentum nicht vom Vertreter, sondern gemäß § 929 S. 1 direkt vom Veräußerer dadurch, dass der handelnde Vertreter als Besitzmittler od. -diener angesehen wird. Meiner Meinung nach bedarf es hier einer teleologischen Reduktion bei der Auslegung des § 164 - soweit der Vertragspartner kein Interesse an der Offenlegung hat, wer sein Geschäftspartner sein wird. Neben dem Rechtsinstitut des Geschäfts für den, den es angeht, sind eine Reihe von gesetzlichen Tatbeständen als gesetzliche Ausnahme vom Offenheitserfordernis normiert, aber diese gesetzlichen Ausnahmen sind keine echten Fälle der direkten Stellvertretung, weil die ohne Offenkundigkeit eintretenden Rechtsfolgen nicht rechtsgeschäftliche, sondern gesetzliche Rechtsfolgen sind.

古群山群島의 地質과 地形에 關한 硏究

金大經 전주교육대학교 1995 論文集 Vol.31 No.-

1) The topography of this district is made up of land islands of the shallow sea formed by the old stage monadnocks, which the sea level rising in the postglacial age brought about. 2) The fault can be classified into several types '?east-northern, west-southern, north-southern, and west-eastern. And this fault forms a fold coastal topography. 3) The coastal topography was investigated about sea cliffs, wave-cut platforms, and coastal sand dunes. 4) Tafoni in this district are found in many places and some of them are combined with notches into large scale ones. 5) Tafoni were formed in the processes of repetition between freezing and melting in a half-dry and cold climate.

리프팅 기법을 이용한 semi-blind 워터마킹

김대경 한양대학교 이학기술연구소 2002 이학기술연구지 Vol.5 No.-

두 개의 필터 계수집합으로 리프팅 기법을 이용하여 두 단계 웨이브렛 분해를 한후 주변의 메디안 값보다 큰 픽셀에 워터마크를 삽입하고 이 위치에 플레그 값을 1호정한다. 공격을 한 후 같은 방법으로 워터마크를 추출하여 플레그 값을 비교하여 저작권을 증명한다. Recently, digital contents can be easily accessed and modified by various digital technology. For Protecting copyright or intellectual properties of digital data, digital watermarking technique has attracted considerable. In this paper, we propose a robust watermarking scheme for digital images based on the lifting scheme which provides simple construction of second generation wavelets. The original image is transformed into wavelet domain two sets of lifting filters; one is for usual wavelet filter, the ithers is for embedding watermarks whose locations are created randomly in a selected wavelet domain with secret key.

Tweeting Politics - An exploratory study to examine the motivations for Twitter use among politically interested Internet users in South Korea

김대경 한국정치커뮤니케이션학회 2012 정치커뮤니케이션 연구 Vol.0 No.27

The aim of this exploratory study is to examine the political influences of Twitter during the local election held on June 2 2010 in South Korea. First, this study examined motivations for why politically interested Internet users were using Twitter during the election campaign based on the uses and gratification approach, and then explored what factors could predict the motivations for using Twitter. An online survey of 292 politically motivated Internet users in this study identified three primary reasons for accessing Twitter: political surveillance/information-seeking, convenience/entertainment, and social utility. Correlation analysis found a positive relationship between Twitter reliance and political behavior, and hierarchical regression revealed that both Twitter reliance and strength of party support were significant predictors of social utility motives for accessing Twitter, which may indicate the discursive nature of Twitter during the election campaign. The findings of this study show both the potentials and limitations of Twitter as a political communication tool. Based on those findings, discussion and direction for future research were followed.

제주관광민속관 운영활성화 전략방안

김대경 제주관광대학 1997 論文集 Vol.3 No.-