• Title/Summary/Keyword: 변화율

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The Closed-form Expressions of Gravity, Magnetic, Gravity Gradient Tensor, and Magnetic Gradient Tensor Due to a Rectangular Prism (직육면체 프리즘에 의한 중력, 자력, 중력 변화율 텐서 및 자력 변화율 텐서의 반응식)

  • Rim, Hyoungrea
    • Geophysics and Geophysical Exploration
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    • v.23 no.1
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    • pp.55-60
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    • 2020
  • The closed-form expressions of gravity, magnetic, gravity gradient tensor, and magnetic gradient tensor due to a rectangular prism are derived. The vertical gravity is derived via triple integration of a rectangular prism in Cartesian coordinates, and the two horizontal components of vector gravity are then derived via cycle permutation of the axis variables of vertical gravity through the axial symmetry of the rectangular prism. The gravity gradient tensor is obtained by differentiating the vector gravity with respect to each coordinate. Using Poisson's relation, a vector magnetic field with constant magnetic direction can be obtained from the gravity gradient tensor. Finally, the magnetic gradient tensor is derived by differentiating the vector magnetic with respect to appropriate coordinates.

Analysis of DoS Attacks using Relationships between the Connection Requests of Hosts and the Traffic Transition Rate of Sowers (호스트의 연결요청과 서버의 트래픽 변화율간 관계를 이용한 DoS 공격 분석)

  • 김가을;고광선;엄영익
    • Proceedings of the Korean Information Science Society Conference
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    • pp.862-864
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    • 2003
  • DoS Attack (Denial-of-Service Attack)이란 공격자가 침입대상 시스템의 시스템 자원과 네트워크 자원을 악의적인 목적으로 소모시키기 위하여 대량의 패킷을 보냄으로써 정상 사용자로 하여금 시스템이 제공하는 서비스를 이용하지 못하도록 하는 공격을 의미한다. 현재 이러한 대부분의 DoS 공격은 인터넷 프로토콜 중 TCP 프로토콜을 주로 이용하고 있다. 이에 호스트의 연결요청이 발생하였을 경우 TCP 프로토콜을 기준으로 서버의 트래픽 변화율을 확인함으로써 DoS 공격을 분석하는 것이다. 서버의 트래픽 변화율은 호스트가 요청한 연결의 발생빈도에 따라 변화하는 서버의 연결요청 처리 시간 변화율을 확인하는 방법으로 확인할 수 있다. 이와 같은 방법으로 확인된 서버의 트래픽 변화율은 일정 시간동안의 변화율 증강을 모니터링 함으로써 DoS 공격에 참여하는 호스트가 요청하는 연결의 발생빈도를 간접적으로 확인하는데 이용할 수 있다. 따라서 본 논문에서는 호스트의 연결요청과 서버의 트래픽 변화율간 관계를 이용하여 DoS 공격의 특성을 분석하고자 한다.

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A Study on Human Sensitivity Evaluation using Plethysmogram (맥파를 이용한 감성 측정법에 대한 검토)

  • 신정상;민병찬;정순철;김상균;민병운;오지영;김유나;김철중
    • Proceedings of the Korean Society for Emotion and Sensibility Conference
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    • pp.427-432
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    • 1999
  • 지금까지 감성측정은 심박 변화율, 피부저항, 피부온도 등의 생리 신호를 측정하고 그 신호를 이용하여 비교, 분석하여 왔다. 심박 변화율, 피부저항, 피부온도와 마찬가지로 자율신경계 반응의 하나로써 맥파 또한 인간의 감성을 평가하는 한 파라미터가 될 수 있음을 예상하고 본 연구를 수행하였다. 건강한 피험자 5명을 상대로 긍정과 부정 시각 자극을 각각 주어서 심박 변화율과 맥파의 생리신호를 측정한 후 그 동안 발표되었던 심박 변화율의 결과를 기준으로 맥파의 결과와 비교, 분석하였다. 그 결과 평균 R-R 간격의 변화율과 맥파의 최고점 평균 시간 간격의 변화율 그리고 맥파의 최대 기울기점 사이의 시간 간격의 변화율이 유사함을 알 수 있었다. 또한 맥파의 Baseline Deflection 과 Amplitude를 이용하여 감성 측정을 시도하였다. 긍정 시각 자극에 비해 부정 시각 자극 일 때 맥파의 최고점 및 최대 기울기점의 평균 시간 간격은 감소하였고, Baseline Deflection은 증가하였고, Amplitude 는 감소하였다. 이는 부정시각 자극이 교감신경계를 활성화시킴을 보여 주는 것이다. 본 연구를 통하여 맥파도 자율 신경계의 반응을 대면하는 생리신호로써 감성 측정에 유용한 도구임을 검증할 수 있었다.

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Students' Recognition and Representation of the Rate of Change in the Given Range of Intervals (구간에서의 변화율에 대한 인식과 표현에 대한 연구)

  • Lee, Dong Gu;Shin, Jaehon
    • Journal of Educational Research in Mathematics
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    • v.27 no.1
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    • pp.1-22
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    • 2017
  • This study investigated three $10^{th}$ grade students' concept of rate of change while they perceived changing values of given functions. We have conducted a teaching experiment consisting of 6 teaching episodes on how the students understood and expressed changing values of functions on certain intervals in accordance with the concept of rate of change. The result showed that the students did use the same word of 'rate of change' in their analysis of functions, but their understanding and expression of the word varied, which turned out to have diverse perceptions with regard to average rate of change. To consider these differences as qualitatively different levels might need further research, but we expect that this research will serve as a foundational study for further research in students' learning 'differential calculus' from the perspective of rate of change.

Analysis of Series Arc Fault Current Using Discrete Wavelet Transform (이산 웨이블렛 변환을 이용한 직렬 아크고장전류 분석)

  • Bang, Sun-Bae;Kim, Chong-Min;Park, Chong-Yeun
    • Proceedings of the KIEE Conference
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    • pp.318-321
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    • 2009
  • 누전차단기 설치 상태에서도 전기화재가 지속적으로 발생함에 따라 전기화재의 원인이 되는 전기 아크에 대한 관심이 증가하고 있는 실정으로 본 논문에서는 UL1699의 아크 저해시험(inhibition tests)에서 제시하고 있는 직렬 아크코장시험(Arc generator test)을 실시하고, 아크고장전류 분석방법으로 최근에 많이 사용되고 있는 이산 웨이블렛 변환을 이용한 3가지 분석방법에 대하여 아크고장전류 검출 확률을 분석하였다. 분석결과, (1) 근사계수 분석에 의한 최대치 변화율 실효치 변화율 분석방법은 46%의 검출 확률을 얻을 수 있었고, (2) 상세계수 분석에 의한 최대치 변화율 실효치 변화율 분석방법은 62%, (3) 근사계수 분석에 의한 잡음량 변화율 shoulder 변화율 분석방법은 100% 검출 확률을 얻을 수 있었다.

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Detection of a Magnetic Dipole by Means of Magnetic Gradient Tensor (자력 변화율 텐서를 이용한 자기 쌍극자 위치 결정)

  • Rim, Hyoung-Rea
    • Journal of the Korean earth science society
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    • v.32 no.6
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    • pp.595-601
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    • 2011
  • In this paper, I propose the algorithm that the location of a magnetic dipole can be detected from the magnetic gradient tensor. I induce the location vector of a vertically magnetizated dipole from the magnetic gradient tensor. Deficit of magnetic moment of magnetic dipole makes the induced location information incomplete. However, if the observation of magnetic gradient tensor would be collected on more points, the algorithm is able to catch the location of the magnetic dipole by clustering the solution of the proposed algorithm. For example, I show that the synthetic case of borehole observation of magnetic gradient tensor can find the source location successively by picking common solution area.

Analysis on High School Students' Recognitions and Expressions of Changes in Concentration as a Rate of Change (변화율 관점에서 농도 변화에 대한 인식과 표현의 변화 과정에 대한 분석)

  • Lee, Dong Gun;Kim, Suk Hui;Ahn, Sang Jin;Shin, Jae Hong
    • Journal of Educational Research in Mathematics
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    • v.26 no.3
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    • pp.333-354
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    • 2016
  • The aim of the present study is twofold. One is to confirm a hypothesis that a student's rate concept influences her conceiving change of a function in the view of rate of change and the other is to build up foundations for understanding the transition process from her rate concept to the concept of rate of change when she investigates the change of concentration as an intensive quantity. We explored how three participating high school students recognized and expressed change of given functions by using their rate concept as a conceptual tool. The result indicates that a change in students' rate concept might have an effect on understanding how function values change in term of rate of change. We also expect that it could be a catalyst for further research for clarifying the relationship between students' rate concept and their development of a concept of rate of change as a foundation for learning calculus.

Handling Deflection Limit in Open-Loop-Onset-Point PIO Analysis (Open-Loop-Onset-Point PIO 해석의 변위한계)

  • Park, Sang-Hyuk
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.2
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    • pp.135-140
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    • 2010
  • A new treatment is proposed to handle a deflection limit in the open-loop-onset-point (OLOP), which is commonly used in the prediction of pilot in-the-loop oscillation (PIO) due to a rate saturation. The new approach is motivated by the frequency response of a stand-alone actuator in that, unlike the suggestion by the original OLOP procedure, the rate limit onset is not delayed to a higher frequency by a deflection limit. Indeed, if a feedback control loop is closed, the rate limit onset can be shifted to a lower frequency since the controller tends to react with larger commands when deflection limited. The amplitude of the command at this onset frequency is combined with the deflection limit to estimate the associated gain reduction in the open-loop-onset-point in the final step of the OLOP process. The comparison of the new approach with the previous method reveals that an inaccurate optimism which can occur in the previous method is corrected by the proposed treatment.

Relationship between Clozapine-Induced Therapeutic Responses and Plasma Homovanillic Acid and 5-Hydroxyindoleacetic Acid Levels in Patients with Chronic Schizophrenia (만성 정신분열증 환자에서 Clozapine의 치료반응과 혈장 Homovanillic Acid 및 5-Hydroxyindoleacetic Acid 농도와의 관계)

  • Kim, Chan-Hyung;Lee, Hong Shick;Kim, Kwang Hyeon;Yoo, Kae Joon
    • Korean Journal of Biological Psychiatry
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    • v.4 no.1
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    • pp.84-94
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    • 1997
  • This study was done to examine changes of plasma homovanillic acid(HVA), 5-hydroxyindoleacetic acid(5-HIAA), and HVA/5-HIAA ratio during an 8-week clozapine trial and to investigate the relationship between the plasma monoamine metabolites and treatment responses. Twenty-seven chronic schizophrenic patiens were treated for 8 weeks with clozapine. The psychopathology was assessed at baseline just clozapine trial and then every 2 weeks until the end of 8-week clozapine treatment using the Positive and Negative Syndrome Scale(PANSS) and the Clinical Global Impression scale(CGI). The plasma HVA and 5-HIAA levels were measured also biweekly using high preformance liquid chromatography with electrochemical detection method. Plasma HVA and 5-HIAA levels were significantly decreased during a 8-week clozapine treatment, although plasma HVA/5-HIAA ratio showed no significant change. The changes of plasma HVA levels were in significant correlations with the changes of PANSS positive scores, of general psychophathology scores, and changes of total socres. The changes of plasma 5-HIAA levels were in signfificant correlations with the changes of PANSS negative scores. But the changes of plasma HVA/5-HIAA ratio had no significant correlation with any PANSS subscale score changes. 48% of the patients treated with clozapine was categorized as responders, who showed at least a 20% decrease in PANSS total socre and a CGI severity score of mildly ill or less(${\leq}3$) at the end pint of the study. The baseline plasma HVA levels and HVA/5-HIAA ratio were significantly higher in responders(N=13) than in nonresponders (N=14). But no significant difference in baseline levels of plasma 5-HIAA was found between responders and nonresponders. At the end point of the study, there was significant difference in the change of plasma HVA between responders(40.3% decrement) and nonresponders(3.1% increment). But no signficant differences in the change of plasma 5-HIAA and the change of plasma HVA/5-HIAA ratio between responders and nonresponders were observed. These results suggest that the antipsychotic effect of clozapine on positive symptoms may be associated with dopaminergic blocking activity, and that on negative symptoms may be associated with serotonergic blocking activity. The baseline plasma HVA levels and the change of HVA levels from baseline may be useful predictors of treatment response with clozapine.

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An Empirical Study on The Relationship between Stock Index Futures Return and Trading Volume (주가지수 선물 수익률과 거래량간 관계에 관한 실증연구)

  • Hwang Sung Soo;Yoo Young Joong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.5 no.6
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    • pp.580-587
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    • 2004
  • The purpose of this study is to examine if the trading volume can apply to the short-term forecasting of the futures price change by verificating the casuality between trading volume and futures price in the KOSPI 200 futures market. The outcome of the research is summarized as follows. In the analysis of subordinate periods, based on the yearly time segments, trading volume were found to lead futures price. As for trading volume, it was under comparably greater influence of its self of the past than the return rate of futures. In the analysis of subordinate periods, based on the trend of the futures market, trading volume lead return rate of futures feebly in a bull market. But return rate of futures lead trading volume significantly in a bearish market.

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