• Title/Summary/Keyword: 엔트로피 모델

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Adsorption of Dyes with Different Functional Group by Activated Carbon: Parameters and Competitive Adsorption (활성탄에 의한 작용기가 다른 염료의 흡착: 파라미터 및 경쟁 흡착)

  • Lee, Jong Jib
    • Applied Chemistry for Engineering
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    • v.33 no.2
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    • pp.151-158
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    • 2022
  • In this paper, parameter characteristics such as pH effect, isotherm, kinetic and thermodynamic parameters and competitive adsorption of dyes including malachite green (MG), direct red 81 (DR 81) and thioflavin S (TS), which have different functional groups, being adsorbed onto activated carbon were investigated. Langmuir, Freundlich and Temkin isotherm models were employed to find the adsorption mechanism. Effectiveness of adsorption treatment of three dyes by activated carbon were confirmed by the Langmuir dimensionless separation factor. The mechanism was found to be a physical adsorption which can be verified through the adsorption heat calculated by Temkin equation. The adsorption kinetics followed the pseudo second order and the rate limiting step was intra-particle diffusion. The positive enthalpy and entropy changes showed an endothermic reaction and increased disorder via adsorption at the S-L interface, respectively. For each dye molecule, negative Gibbs free energy increased with the temperature, which means that the process is spontaneous. In the binary component system, it was found that the same functional groups of the dye could interfere with the mutual adsorption, and different functional groups did not significantly affect the adsorption. In the ternary component system, the adsorption for MG lowered a bit, likely to be disturbed by the other dyes meanwhile DR 81 and TS were to be positively affected by the presence of MG, thus resulting in much higher adsorption.

Applicability of Theoretical Adsorption Models for Studies on Adsorption Properties of Adsorbents(III) (흡착제의 흡착특성 규명을 위한 흡착모델의 적용성 평가(III) - 열역학적 특성을 중심으로)

  • Na, Choon-Ki;Jeong, Jin-Hwa;Park, Hyun-Ju
    • Journal of Korean Society of Environmental Engineers
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    • v.34 no.4
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    • pp.260-269
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    • 2012
  • The aim of this study is to evaluate the applicability of adsorption models for understanding the thermodynamic properties of adsorption process. For this study, the adsorption isotherm data of $NO_3$-N ion onto a commercial anion exchange resin obtained at various experimental conditions, i.e. different initial concentrations of adsorbate, different dosages of adsorbent, and different temperatures, were used in calculating the thermodynamic parameters and the adsorption energy of adsorption process. The Gibbs free energy change (${\Delta}G^0$) of adsorption process could be calculated using the Langmuir constant $b_M$ as well as the Sips constant, even though the results were significantly dependant on the experimental conditions. The thermodynamic parameters such as standard enthalpy change (${\Delta}H^0$), standard entropy change (${\Delta}S^0$) and ${\Delta}G^0$ could be calculated by using the experimental data obtained at different temperatures, if the adsorption data well fitted to the Langmuir isotherm model and the plot of ln b versus 1/T gives a straight line. As an alternative, the empirical equilibrium constant(K) defined as $q_e/C_e$ could be used for evaluating the thermodynamic parameters instead of the Langmuir constant. The results from the applications of D-R model and Temkin model to evaluate the adsorption energy suggest that the D-R model is better than Temkin model for describing the experimental data, and the availability of Temkin model is highly limited by the experimental conditions. Although adsorption energies determined using D-R model show significantly different values depending on the experimental conditions, they were sufficient to show that the adsorption of $NO_3$-N onto anion exchange resin is an endothermic process and an ion-exchange process.

Anomaly Detection for User Action with Generative Adversarial Networks (적대적 생성 모델을 활용한 사용자 행위 이상 탐지 방법)

  • Choi, Nam woong;Kim, Wooju
    • Journal of Intelligence and Information Systems
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    • v.25 no.3
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    • pp.43-62
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    • 2019
  • At one time, the anomaly detection sector dominated the method of determining whether there was an abnormality based on the statistics derived from specific data. This methodology was possible because the dimension of the data was simple in the past, so the classical statistical method could work effectively. However, as the characteristics of data have changed complexly in the era of big data, it has become more difficult to accurately analyze and predict the data that occurs throughout the industry in the conventional way. Therefore, SVM and Decision Tree based supervised learning algorithms were used. However, there is peculiarity that supervised learning based model can only accurately predict the test data, when the number of classes is equal to the number of normal classes and most of the data generated in the industry has unbalanced data class. Therefore, the predicted results are not always valid when supervised learning model is applied. In order to overcome these drawbacks, many studies now use the unsupervised learning-based model that is not influenced by class distribution, such as autoencoder or generative adversarial networks. In this paper, we propose a method to detect anomalies using generative adversarial networks. AnoGAN, introduced in the study of Thomas et al (2017), is a classification model that performs abnormal detection of medical images. It was composed of a Convolution Neural Net and was used in the field of detection. On the other hand, sequencing data abnormality detection using generative adversarial network is a lack of research papers compared to image data. Of course, in Li et al (2018), a study by Li et al (LSTM), a type of recurrent neural network, has proposed a model to classify the abnormities of numerical sequence data, but it has not been used for categorical sequence data, as well as feature matching method applied by salans et al.(2016). So it suggests that there are a number of studies to be tried on in the ideal classification of sequence data through a generative adversarial Network. In order to learn the sequence data, the structure of the generative adversarial networks is composed of LSTM, and the 2 stacked-LSTM of the generator is composed of 32-dim hidden unit layers and 64-dim hidden unit layers. The LSTM of the discriminator consists of 64-dim hidden unit layer were used. In the process of deriving abnormal scores from existing paper of Anomaly Detection for Sequence data, entropy values of probability of actual data are used in the process of deriving abnormal scores. but in this paper, as mentioned earlier, abnormal scores have been derived by using feature matching techniques. In addition, the process of optimizing latent variables was designed with LSTM to improve model performance. The modified form of generative adversarial model was more accurate in all experiments than the autoencoder in terms of precision and was approximately 7% higher in accuracy. In terms of Robustness, Generative adversarial networks also performed better than autoencoder. Because generative adversarial networks can learn data distribution from real categorical sequence data, Unaffected by a single normal data. But autoencoder is not. Result of Robustness test showed that he accuracy of the autocoder was 92%, the accuracy of the hostile neural network was 96%, and in terms of sensitivity, the autocoder was 40% and the hostile neural network was 51%. In this paper, experiments have also been conducted to show how much performance changes due to differences in the optimization structure of potential variables. As a result, the level of 1% was improved in terms of sensitivity. These results suggest that it presented a new perspective on optimizing latent variable that were relatively insignificant.

Deblocking Filter for Low-complexity Video Decoder (저 복잡도 비디오 복호화기를 위한 디블록킹 필터)

  • Jo, Hyun-Ho;Nam, Jung-Hak;Jung, Kwang-Su;Sim, Dong-Gyu;Cho, Dae-Sung;Choi, Woong-Il
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.47 no.3
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    • pp.32-43
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    • 2010
  • This paper presents deblocking filter for low-complexity video decoder. Baseline profile of the H.264/AVC used for mobile devices such as mobile phones has two times higher compression performance than the MPEG-4 Visual but it has a problem of serious complexity as using 1/4-pel interpolation filter, adaptive entropy model and deblocking filter. This paper presents low-complexity deblocking filter for decreasing complexity of decoder with preserving the coding efficiency of the H.264/AVC. In this paper, the proposed low-complexity deblocking filter decreased 49% of branch instruction than conventional approach as calculating value of BS by using the CBP. In addition, a range of filtering of strong filter applied in intra macroblock boundaries was limited to two pixels. According to the experimental results, the proposed low-complexity deblocking filter decreased -0.02% of the BDBitrate comparison with baseline profile of the H.264/AVC, decreased 42% of the complexity of deblocking filter, and decreased 8.96% of the complexity of decoder.

BGK 수치기법을 이용한 로켓 노즐 내의 유동장 해석

  • 신동신;이재성
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2000.04a
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    • pp.16-16
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    • 2000
  • 충격파를 포함하는 초음속 유동을 해석하는 수치해법 중에서 많이 사용되어진 것은 엄밀 및 근사 리만 해법과 플럭스 분할 기법들로서 이들은 Euler 방정식에 기반을 두고 선형 또는 비선형파의 상호작용을 풍상 차분법으로 기술하는 방법들이다. 이러한 수치기법들은 과거 광범위하게 사용되어 왔으나 최근 여러 가지 단점이 발견되었다. 이와 같은 문제점을 극복하고자 입자의 통계적인 운동을 기술하는 기체 운동론에 근거하여 BGK 수치기법이 제시되었다. 이는 비충돌 볼츠만 방정식으로부터 입자의 수준에서 플럭스 분할 기법 형태의 풍상차분법을 구현하는 것으로 볼츠만 방정식의 충돌항을 BGK 모델로 대치하고 이것의 적분해로부터 수치 플럭스를 구한다. 이 수치기법은 기존의 리만해법에 비하여 수치적으로나 물리적으로 매우 타당한 성질인 강건성, 정확성, 엔트로피 조건, 양수보존성 등을 가지고 있음이 밝혀졌다. 이와 같은 수치기법을 사용하여 로켓 노즐 내의 아음속, 천이음속, 초음속에서의 유동장 해석을 위한 프로그램을 작성하였다. 시간 적분에 대하여는 정상 상태의 계산을 위하여 내재적 시간 적분 방법을 사용하였으며, 공간 이산화 방법으로는 임의의 제어체적에 대하여 적분형 보존 방정식을 적용하는 유한 체적법을 사용하였다. 초음속 입구 유동과 출구에서 초음속과 저음속 유동의 두가지 경우를 고려하여 얻은 결과를 기존의 연구 결과와 비교하여 본 결과 잘 일치하였다. 입구 유동이 저음속이고 출구 유동이 초음속인 경우에 대하여도 해석결과가 실험결과와 잘 일치하였다. 상대적으로 낮은 온도, 압력 조건과 높은 온도, 압력 조건을 가지는 고체 로켓 모터 노즐 내의 유동을 해석하였다. 이들 해석 결과를 전압, 전온도로 표준화시킨 결과 서로 일치하였으며, 파라서 저온, 저압에서 얻은 결과도 표준화시킬 경우, 고온, 고압에서도 사용될 수 있음을 알 수 있었다.의 영향에 초점을 맞추었다.다고 판단되며 배기 가스 자체에 대기 공기중에 함유되어 있던 습기가 얼어붙는(Icing화) 문제가 발생하기 때문에 배기가스의 Icing을 방지하기 위하여 압축기 끝단에서 공기를 추출하여 배기부분에 송출할 필요성이 있는 것으로 판단되었다. 출구가스의 기체 유동속도가 매우 빠르므로 (100-l10m.sec) 이를 완화하기 위한 디퓨저의 설계가 요구된다고 판단된다. 또 연소기 후방에 물을 주입하는 경우 열교환기 및 기타 부분품에 발생할 수 있는 부식 및 열교환 효율 저하도 간과할 수 없는 문제로 파악되었다. 이러한 기술적 문제가 적절히 해결되는 경우 비활성 가스 제너레이터는 민수용으로는 대형 빌딩, 산림, 유조선 등의 화재에 매우 적절히 사용되어 질 수 있을 뿐 아니라 군사적으로도 군사작전 중 및 공군 기지의 화재 그리고 지하벙커에 설치되어 있는 고급 첨단 군사 장비 등의 화재 뿐 아니라 대간첩작전 등에 효과적으로 활용될 수 있을 것으로 판단된다.가 작으며, 본 연소관에 충전된 RDX/AP계 추진제의 경우 추진제의 습기투과에 의한 추진제 물성 변화는 미미한 것으로 나타났다.의 향상으로, 음성개선에 효과적이라고 사료되었으며, 이 방법이 편측 성대마비 환자의 효과적인 음성개선의 치료방법의 하나로 응용될 수 있으리라 생각된다..7%), 혈액투석, 식도부분절제술 및 위루술·위회장문합술을 시행한 경우가 각 1례(2.9%)씩이었다. 13) 심각한 합병증은 9례(26.5%)에서 보였는데 그중 식도협착증이 6례(17.6%), 급성신부전증 1례(2.9%), 종격동기흉과 폐염이 병발한 경우와 폐염이 각 1례(2.9%)였다. 14) 식도경 시행회수는 1회가 17례(54.8%), 2회가 9례(29.0%), 3회 이상이 5례(16.1%)였다.EX>$IC_{50}$/ 값이 210 $\mu\textrm{g}$<

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Building Domain Ontology through Concept and Relation Classification (개념 및 관계 분류를 통한 분야 온톨로지 구축)

  • Huang, Jin-Xia;Shin, Ji-Ae;Choi, Key-Sun
    • Journal of KIISE:Software and Applications
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    • v.35 no.9
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    • pp.562-571
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    • 2008
  • For the purpose of building domain ontology, this paper proposes a methodology for building core ontology first, and then enriching the core ontology with the concepts and relations in the domain thesaurus. First, the top-level concept taxonomy of the core ontology is built using domain dictionary and general domain thesaurus. Then, the concepts of the domain thesaurus are classified into top-level concepts in the core ontology, and relations between broader terms (BT) - narrower terms (NT) and related terms (RT) are classified into semantic relations defined for the core ontology. To classify concepts, a two-step approach is adopted, in which a frequency-based approach is complemented with a similarity-based approach. To classify relations, two techniques are applied: (i) for the case of insufficient training data, a rule-based module is for identifying isa relation out of non-isa ones; a pattern-based approach is for classifying non-taxonomic semantic relations from non-isa. (ii) For the case of sufficient training data, a maximum-entropy model is adopted in the feature-based classification, where k-NN approach is for noisy filtering of training data. A series of experiments show that performances of the proposed systems are quite promising and comparable to judgments by human experts.

Analysis on Isotherm, Kinetic and Thermodynamic Properties for Adsorption of Acid Fuchsin Dye by Activated Carbon (활성탄에 의한 Acid Fuchsin 염료의 흡착에 대한 등온선, 동력학 및 열역학 특성치에 대한 해석)

  • Lee, Jong Jib
    • Korean Chemical Engineering Research
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    • v.58 no.3
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    • pp.458-465
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    • 2020
  • Isotherms, kinetics and thermodynamic properties for adsorption of acid fuchsin (AF) dye by activated carbon were carried out using variables such as dose of adsorbent, pH, initial concentration and contact time and temperature. The effect of pH on adsorption of AF showed a bathtub with high adsorption percentage in acidic (pH 8). Isothermal adsorption data were fitted to the Freundlich, Langmuir, and Dubinin-Radushkevich isotherm models. Freundlich isothem model showed the highest agreement and confirmed that the adsorption mechanism was multilayer adsorption. It was found that adsorption capacity increased with increasing temperature. Freundlich's separation factor showed that this adsorption process was an favorable treatment process. Estimated adsorption energy by Dubinin-Radushkevich isotherm model indicated that the adsorption of AF by activated carbon is a physical adsorption. Adsorption kinetics was found to follow the pseudo-second-order kinetic model. Surface diffusion at adsorption site was evaluated as a rate controlling step by the intraparticle diffusion model. Thermodynamic parameters such as activation energy, Gibbs free energy, enthalpy entropy and isosteric heat of adsorption were investigated. The activation energy and enthalpy change of the adsorption process were 21.19 kJ / mol and 23.05 kJ / mol, respectively. Gibbs free energy was found that the adsorption reaction became more spontaneously with increasing temperature. Positive entropy was indicated that this process was irreversible. The isosteric heat of adsorption was indicated physical adsorption in nature.

Classification of Non-Signature Multimedia Data Fragment File Types With Byte Averaging Gray-Scale (바이트 평균의 Gray-Scale화를 통한 Signature가 존재하지 않는 멀티미디어 데이터 조각 파일 타입 분류 연구)

  • Yoon, Hyun-ho;Kim, Jae-heon;Cho, Hyun-soo;Won, Jong-eun;Kim, Gyeon-woo;Cho, Jae-hyeon
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.30 no.2
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    • pp.189-196
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    • 2020
  • In general, fragmented files without signatures and file meta-information are difficult to recover. Multimedia files, in particular, are highly fragmented and have high entropy, making it almost impossible to recover with signature-based carving at present. To solve this problem, research on fragmented files is underway, but research on multimedia files is lacking. This paper is a study that classifies the types of fragmented multimedia files without signature and file meta-information. Extracts the characteristic values of each file type through the frequency differences of specific byte values according to the file type, and presents a method of designing the corresponding Gray-Scale table and classifying the file types of a total of four multimedia types, JPG, PNG, H.264 and WAV, using the CNN (Convolutional Natural Networks) model. It is expected that this paper will promote the study of classification of fragmented file types without signature and file meta-information, thereby increasing the possibility of recovery of various files.

Encounter of Lattice-type coding with Wiener's MMSE and Shannon's Information-Theoretic Capacity Limits in Quantity and Quality of Signal Transmission (신호 전송의 양과 질에서 위너의 MMSE와 샤논의 정보 이론적 정보량 극한 과 격자 코드 와의 만남)

  • Park, Daechul;Lee, Moon Ho
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.8
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    • pp.83-93
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    • 2013
  • By comparing Wiener's MMSE on stochastic signal transmission with Shannon's mutual information first proved by C.E. Shannon in terms of information theory, connections between two approaches were investigated. What Wiener wanted to see in signal transmission in noisy channel is to try to capture fundamental limits for signal quality in signal estimation. On the other hands, Shannon was interested in finding fundamental limits of signal quantity that maximize the uncertainty in mutual information using the entropy concept in noisy channel. First concern of this paper is to show that in deriving limits of Shannon's point to point fundamental channel capacity, Shannon's mutual information obtained by exploiting MMSE combiner and Wiener filter's MMSE are interelated by integro-differential equantion. Then, At the meeting point of Wiener's MMSE and Shannon's mutual information the upper bound of spectral efficiency and the lower bound of energy efficiency were computed. Choosing a proper lattice-type code of a mod-${\Lambda}$AWGN channel model and MMSE estimation of ${\alpha}$ confirmed to lead to the fundamental Shannon capacity limits.

A Frame-based Coding Mode Decision for Temporally Active Video Sequence in Distributed Video Coding (분산비디오부호화에서 동적비디오에 적합한 프레임별 모드 결정)

  • Hoangvan, Xiem;Park, Jong-Bin;Shim, Hiuk-Jae;Jeon, Byeung-Woo
    • Journal of Broadcast Engineering
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    • v.16 no.3
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    • pp.510-519
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    • 2011
  • Intra mode decision is a useful coding tool in Distributed Video Coding (DVC) for improving DVC coding efficiency for video sequences having fast motion. A major limitation associated with the existing intra mode decision methods, however, is that its efficiency highly depends on user-specified thresholds or modeling parameters. This paper proposes an entropy-based method to address this problem. The probabilities of intra and Wyner?Ziv (WZ) modes are determined firstly by examining correlation of pixels in spatial and temporal directions. Based on these probabilities, entropy of the intra and the WZ modes are computed. A comparison based on the entropy values decides a coding mode between intra coding and WZ coding without relying on any user-specified thresholds or modeling parameters. Experimental results show its superior rate-distortion performance of improvements of PSNR up to 2 dB against a conventional Wyner?Ziv coding without intra mode decision. Furthermore, since the proposed method does not require any thresholds or modeling parameters from users, it is very attractive for real life applications.