An Improved Cross Entropy-Based Frequency-Domain Spectrum Sensing

타사미아,구준롱,장성진,김재명,Ahmed, Tasmia,Gu, Junrong,Jang, Sung-Jeen,Kim, Jae-Moung The Institute of Electronics and Information Engin 2011 電子工學會論文誌-TC (Telecommunications) Vol.41 No.8

본 논문은 주파수 영역에서 과거와 현재에 센싱된 결과들의 관계를 이용한 스펙트럼 센싱기법을 제안하였다. 기존에 제안된 대부분의 스펙트럼 센싱기법은 해당 시간에 센싱된 우선사용자의 신호만을 다루고 있다. 해당 시간 이전의 우선사용자의 상태는 조건부확률을 사용하여 검출기의 신뢰성을 증가시킬 수 있다. 따라서, 본 논문은 이전 시간과 해당 시간의 스펙트럼 센싱 결과를 사용하는 cross entropy 기반의 스펙트럼 센싱기법을 제안하며 이를 통해 우선사용자 신호 검출 성능을 향상시키고 잡음에 강인한 성능을 가질 수 있다. 이전 시간에 검출된 신호가 잡음인 경우 cross entropy 기반의 스펙트럼 센싱 성능 감소는 기존의 entropy 기반의 센싱기법과 동일하게 된다. 이러한 문제를 해결하기 위해 본 논문에서는 보다 향상된 cross entropy 센싱기법을 제안하였다. 본 논문은 시뮬레이션을 통해 가장 최근에 제안된 주파수 영역에서의 entropy 기반 스펙트럼 센싱기법 보다 제안된 방법이 더 나은 성능을 보이는 것을 보였다. In this paper, we present a spectrum sensing method by exploiting the relationship of previous and current detected data sets in frequency domain. Most of the traditional spectrum sensing methods only consider the current detected data sets of Primary User (PU). Previous state of PU is a kind of conditional probability that strengthens the reliability of the detector. By considering the relationship of the previous and current spectrum sensing, cross entropy-based spectrum sensing is proposed to detect PU signal more effectively, which has a strengthened performance and is robust. When previous detected signal is noise, the discriminating ability of cross entropy-based spectrum sensing is no better than conventional entropy-based spectrum sensing. To address this problem, we propose an improved cross entropy-based frequency-domain spectrum sensing. Regarding the spectrum sensing scheme, we have derived that the proposed method is superior to the cross entropy-based spectrum sensing. We proceed a comparison of the proposed method with the up-to-date entropy-based spectrum sensing in frequency-domain. The simulation results demonstrate the performance improvement of the proposed spectrum sensing method.

An Improved Cross Entropy-Based Frequency-Domain Spectrum Sensing

타사미아(Tasmia Ahmed),구준롱(Junrong Gu),장성진(Sung Jeen Jang),김재명(Jae Moung Kim) 大韓電子工學會 2011 電子工學會論文誌-TC (Telecommunications) Vol.48 No.3

본 논문은 주파수 영역에서 과거와 현재에 센싱된 결과들의 관계를 이용한 스펙트럼 센싱기법을 제안하였다. 기존에 제안된 대부분의 스펙트럼 센싱기법은 해당 시간에 센싱된 우선사용자의 신호만을 다루고 있다. 해당 시간 이전의 우선사용자의 상태는 조건부확률을 사용하여 검출기의 신뢰성을 증가시킬 수 있다. 따라서, 본 논문은 이전 시간과 해당 시간의 스펙트럼 센싱결과를 사용하는 cross entropy 기반의 스펙트럼 센싱기법을 제안하며 이를 통해 우선사용자 신호 검출 성능을 향상시키고 잡음에 강인한 성능을 가질 수 있다. 이전 시간에 검출된 신호가 잡음인 경우 cross entropy 기반의 스펙트럼 센싱 성능 감소는 기존의 entropy 기반의 센싱기법과 동일하게 된다. 이러한 문제를 해결하기 위해 본 논문에서는 보다 향상된 cross entropy 센싱기법을 제안하였다. 본 논문은 시뮬레이션을 통해 가장 최근에 제안된 주파수 영역에서의 entropy 기반 스펙트럼 센싱기법보다 제안된 방법이 더 나은 성능을 보이는 것을 보였다. In this paper, we present a spectrum sensing method by exploiting the relationship of previous and current detected data sets in frequency domain. Most of the traditional spectrum sensing methods only consider the current detected data sets of Primary User (PU). Previous state of PU is a kind of conditional probability that strengthens the reliability of the detector. By considering the relationship of the previous and current spectrum sensing, cross entropy-based spectrum sensing is proposed to detect PU signal more effectively, which has a strengthened performance and is robust. When previous detected signal is noise, the discriminating ability of cross entropy-based spectrum sensing is no better than conventional entropy-based spectrum sensing. To address this problem, we propose an improved cross entropy-based frequency-domain spectrum sensing. Regarding the spectrum sensing scheme, we have derived that the proposed method is superior to the cross entropy-based spectrum sensing. We proceed a comparison of the proposed method with the up-to-date entropy-based spectrum sensing in frequency-domain. The simulation results demonstrate the performance improvement of the proposed spectrum sensing method.

Order υ Entropy and Cross Entropy of Uncertain Variables for Portfolio Selection

Alireza Sajedi,Gholamhossein Yari 한국지능시스템학회 2020 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.20 No.1

In this study, we proposed definition of order υ entropy and order υ cross entropy of uncertain variables under uncertainty theory. Moreover, order υ entropy and order υ cross entropy of uncertain variables were applied to mean-variance portfolio selection model. We also attempted to examine the applications of these measures with different order υ values. The effect of the υ in order υ entropy and cross entropy on portfolio selection were considered using the order υ entropy-mean-variance and 571781799order υ entropy-mean-variance presented models. As a result of this approach, by using different values of υ, diversity of asset allocations could be achieved.

연관성 규칙 평가를 위한 대칭적 균형화 교차 엔트로피 측도

박희창 한국자료분석학회 2018 Journal of the Korean Data Analysis Society Vol.20 No.2

Among the various entropy-based measures, meaningful measures for evaluating association rules are joint entropy, conditional entropy, mutual information, cross entropy, and balanced cross entropy. The balanced cross entropy is a measure that measures only one direction, although it is an evaluation criterion that simultaneously considers the strength of all possible association rules (Park, 2017a). In addition, the symmetric J measure is a measure that adds only directionality to the existing cross entropy (Park, 2017b). In this paper, we proposed a symmetrically balanced cross entropy considering the advantages of symmetric J measure and balanced cross entropy for evaluation of association rules. As a result, the symmetrically balanced cross entropy had a positive or a negative value, so we could know the direction of association. In the case of the balanced cross entropy and a symmetrically balanced cross entropy, we could see that their signs were different because the former was considered as one direction only, while the latter was considered as considering both directions. 여러 가지 엔트로피 기반 측도들 중에서 연관성 규칙을 평가하는 데 의미 있는 측도에는 결합 엔트로피, 조건부 엔트로피, 상호정보량, 교차 엔트로피, 그리고 균형화된 교차 엔트로피 등이 있다(Park, 2016b). 이들 중에서 균형화된 교차 엔트로피는 모든 가능한 연관성의 강도를 동시에 고려한 평가 기준이기는 하나 한쪽 방향으로만 측정하는 측도이다. 이에 반해 대칭적 J 측도는 기존의 교차 엔트로피에 방향성만을 추가한 측도라고 할 수 있다. 본 논문에서는 연관성 규칙의 평가 기준으로 사용하기 위해 대칭적 J 측도와 균형화된 교차 엔트로피의 장점을 동시에 고려한 대칭적 균형화 교차 엔트로피를 제안하고 예를 통해 그 유용성을 살펴보았다. 그 결과, 측도 균형화된 교차 엔트로피와 대칭적 균형화 교차 엔트로피는 양의 값 또는 음의 값으로 나타나므로 연관성의 방향을 알 수 있으나, 교차 엔트로피와 대칭적 J 측도는 항상 양의 값을 취하고 있어서 이 측도만으로는 연관성의 방향을 알 수가 없는 것으로 나타났다. 또한 균형화된 교차 엔트로피와 대칭적 균형화 교차 엔트로피의 변화하는 양상을 살펴보면 그들의 부호가 다르게 나타나는 사례를 찾아볼 수 있는데 그 이유는 전자가 한 방향만을 고려하는 측도인 반면에 후자는 양 방향을 고려하기 때문으로 해석된다.

디자인의 감성만족도 평가를 위한 시선 엔트로피의 활용에 관한 기초연구

이예진(Yejin Lee),정광태(Kwang Tae Jung),이현철(Hyun Chul Lee) 대한인간공학회 2020 大韓人間工學會誌 Vol.39 No.5

Objective: The purpose of this study is to find out the possibility of using eye movement entropy for the emotional satisfaction evaluation of design. Background: Emotion is often considered important in product design. Emotion, however, is very comprehensive and difficult to express clearly, so there have been attempts to analyze it through eye tracking. Most researchers used basic eye tracking metrics such as eye fixation time, time to first fixation, the number of eye fixation, and the change of pupil size to evaluate emotion. Basic metrics are effective in analyzing the importance of each design element but difficulties arise when analyzing the overall aspects of the design. In order to assess user"s emotion about design, it is necessary to present eye movement as a single metric. Therefore, we suggest the possibility of using the eye movement entropy. Method: A literature study was conducted to determine how to obtain entropies from eye movement. In addition, an experiment was conducted to identify the relationship between emotional satisfaction and eye movement entropy. For the experiment, the front design images of three car models were used as experimental stimuli. Eight college students participated in the experiment and Tobii Glasses 2 was used to record eye movement while looking at car images. Car images were presented on the 65-inch TV screen. Subjects evaluated how much emotionally satisfied to the car design on a five-point scale at the end of each image presentation. Results: In the analysis of emotional satisfaction for car designs, it showed that a significant difference exist between car R and H. Therefore, eye movement entropies; Shannon entropy, Markov entropy, dwell time entropy, and heatmap entropy for R and H were calculated and analyzed. In the analysis of entropies for R and H, all entropies showed the average of the high entropy in the design model with highly emotional satisfaction. However, the means of Shannon, Morkov, dwell time entropy showed no significant difference between R and H, and heatmap entropy showed a significant difference. In the correlation analysis, there was no significant correlation between the emotional satisfaction and the Shannon, Markov and dwell time entropy, but there was a positive correlation (p=0.552) with the heatmap entropy. Conclusion: This study was carried out to know if the eye movement entropy can be used for the emotional satisfaction evaluation of design. The entropies derived from the gazeplot and heatmap of the eye movement showed a meaningful relationship with the emotional satisfaction, especially the heatmap entropy showed stronger correlation with the emotional satisfaction. Eye movement entropies were higher in the design with high emotional satisfaction, which means that the higher the emotion satisfaction level, the more the subject"s eye movement. From the results, it can be seen that eye movement entropy can be used as a meaningful physiological measure for evaluating the emotional satisfaction of a design, especially the heatmap entropy can be used as the most appropriate entropy measure. Application: The results of this study could be used as a guide to the use of eye tracking for the emotional satisfaction evaluation of design.

차량 잡음 환경에서 엔트로피 기반의 음성 구간 검출

노용완,이규범,이우석,홍광석,Roh, Yong-Wan,Lee, Kue-Bum,Lee, Woo-Seok,Hong, Kwang-Seok 한국융합신호처리학회 2008 융합신호처리학회 논문지 (JISPS) Vol.9 No.2

정확한 음성 구간 검출은 음성 인식 및 음성 코딩 그리고 음성 통신 시스템 등과 같은 음성 어플리케이션의 성능에 큰 영향을 미친다. 본 논문에서는 실제 운전하고 있는 상태에서 다양한 차량 노이즈 환경의 음성 구간 검출 방법을 제안한다. 기존의 음성 구간 검출은 시간 에너지, 주파수 에너지, 영 교차율, spectral entropy 등 다양한 방법을 사용하였으며 잡음 환경에서 급격하게 성능이 저하되는 단점이 있었다. 본 논문에서는 기존의 spectral entropy를 기반으로 하여 MFB(Mel-frequency Filter Banks) spectral entropy, 기울기 FFT(Fast Fourier Transform) spectral entropy, 기울기 MFB spectral entropy를 이용한 음성 구간 검출 방법을 제안한다. MFB는 멜 스케일과 FFT를 곱한 것으로 멜 스케일은 인간이 소리를 인지할 때 주파수에 대해 비선형적인 스케일이며 음성의 특징을 잘 반영한다. 제안한 MFB spectral entropy 방법은 다양한 차량 잡음 환경에서 음성 및 비음성 분별 능력을 향상시킬 수 있으며 실험 결과 93.21%의 음성 구간 검출율을 나타내었다. 이는 기존의 spectral entropy 방법과 비교할 때 MFB를 이용한 음성 구간 검출 방법이 3.2%의 검출율이 향상되었다. Accurate voice activity detection have a great impact on performance of speech applications including speech recognition, speech coding, and speech communication. In this paper, we propose methods for voice activity detection that can adapt to various car noise situations during driving. Existing voice activity detection used various method such as time energy, frequency energy, zero crossing rate, and spectral entropy that have a weak point of rapid. decline performance in noisy environments. In this paper, the approach is based on existing spectral entropy for VAD that we propose voice activity detection method using MFB(Met-frequency filter banks) spectral entropy, gradient FFT(Fast Fourier Transform) spectral entropy. and gradient MFB spectral entropy. FFT multiplied by Mel-scale is MFB and Mel-scale is non linear scale when human sound perception reflects characteristic of speech. Proposed MFB spectral entropy method clearly improve the ability to discriminate between speech and non-speech for various in noisy car environments that achieves 93.21% accuracy as a result of experiments. Compared to the spectral entropy method, the proposed voice activity detection gives an average improvement in the correct detection rate of more than 3.2%.

Portfolio Selection in the Credibilistic Framework Using Renyi Entropy and Renyi Cross Entropy

Gholanhossein Yari,Alireza Sajedi,Mohamadtaghi Rahimi 한국지능시스템학회 2018 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.18 No.1

In this study, the Renyi entropy-mean-variance maximization and Renyi cross entropy-mean-variance minimization models for portfolio selection with fuzzy return were investigated under the credibility theory framework. We also attempted to examine the relationship between credibilistic Renyi entropy-mean-variance and Renyi cross entropy-mean-variance models. The effect of the parameter in Renyi entropy and Renyi cross entropy on optimal portfolio selection was considered using the presented models.

엔트로피와 변증법의 관계

이재은(Lee Jae-eun) 현대미술사학회 2009 현대미술사연구 Vol.26 No.-

This is a study on the relationship between entropy and dialectic of Robert Smithson’s earth art. Robert Smithson definitely was a pioneer of Earth art in the late 1960’s. His earth works was located in abandoned site away from civilization called ‘industrial ruin’ for himself. And Smithson had always hoped these works would be permanent. These characteristics make his earth works distinctive from other earth artists’ works. I consider that his attention to entropy and dialectic made him create such differences. His interest in entropy started from American political and social situations in the 1960’s. In late the 1960’s, America was in chaos from the ‘right of freedom’ of the black people and the strike for renunciation of Vietnam War by young people. The intellectual class seemed to believe that it was the destiny of society to run in the direction of entropy. Robert Smithson who was skeptical about American society thought ‘entropy’ is the proper diagnosis to describe the collapsing of traditional and industrial American society. Also he understood that ‘process’ step among the principal of dialectic’ would cause entropic situation to change. So we need to examine how two different concepts as such entropy and dialectic work in Smithson’ works without crash. In chapter 2, we are going to look at the background of the appearance of entropy, which is explaining the increase of chaos based on the second law of thermodynamics and the opinion about entropy of Robert Smithson. In chapter 3, we are going to compare Hegel’s principal of dialectic with Robert Smithson. In chapter 4, we are going to study the theoretical fundamental which makes entropy(stillness of material) and the principal of dialectic(improvement) revealed from his work at the same time. And we are going to see how Robert Smithson breathed the relation of ‘entropy’ and the ‘principal of dialectic’ into his works by through Spiral Jetty. By this study, we will be able to know Robert Smithson pursued the change of American industrial capitalism by the earth works based on entropy and dialectic and also he introduced the chaos which comes with the process of change as the main subject of his works.

Entropy Analysis in Foreign Exchange Markets and Economic Crisis

Jin-Gi Ha,임규빈,김승환,정우성 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.4

We investigate the relative market efficiency in 11 foreign exchange markets by using the Lempel- Ziv (LZ) complexity algorithm and several entropy values such as the Shannon entropy, the approximate entropy, and the sample entropy. With daily data in 11 foreign exchange markets from Jan. 2000 to Sep. 2011, we observe that mature markets have higher LZ complexities and entropy values than emerging markets. Furthermore, with sliding time windows, we also investigate the temporal evolutions of those entropies from Jan. 1994 to Sep. 2011, and we find that, after an economic crisis, the approximate entropy and the sample entropy of mature markets such as Japan, Europe and the United Kingdom suddenly become lower.

A Study of Pre-service Chemistry Teacher`s Understanding on Entropy

( Young Jin Seo ),( Hun Gi Hong ) 한국과학교육학회 2012 한국과학교육학회지 Vol.32 No.3

Abstract: In this study, we conducted preliminary survey, diagnostic test and in-depth interview in order to study Korean pie-service chemistry teachers understanding on entropy and investigate how Korean pie-service chemistry teachers deal with the natural phenomenon which is related to entropy conceptions. Firstly, as a result of the preliminary survey, it was found that pre-service chemistry teachers strongly recognized entropy as the degree of disorder. Secondly, the diagnostic test showed pie-service chemistry teachers were mostly confused about whether the entropy of the universe increases during a spontaneous change, and they had a tendency to interpret the natural phenomenon related to entropy change as the change of disorder. Finally, during in-depth interview, after we explained entropy change in all diagnostic test questions with the concept of microstate, pie-service chemistry teachers revealed a better understanding about entropy. Through this research, pre-service chemistry teachers had an opportunity to reflect on their deficiencies of entropy conceptions, which will ultimately help students to approach the concept of entropy more correctly.