Denoising Algorithm based on Wavelets and Hidden Markov Model

학위논문 (석사)-- 서울대학교 대학원 : 자연과학대학 수리과학부, 2019. 2. 이기암.In this paper, we mainly discuss an algorithm that can be applied to actual signal denoising by using regression models and functional decomposition methods. In section1, the least mean squares(LMS) algorithm, which is representative of the linear regression model, is introduced and an explicit form of optimized weight is presented. We update the weight using the stochastic gradient descent algorithm. In addition, we introduce a regularization term as a way to compensate for problems when simulating actual data. In section2, we provide short time Fourier transform and wavelet transform as tools for signal analysis. In particular, we explore the properties of wavelets from the construction of wavelets and decompose L_2 functions based on them. In section3, we introduce a probabilistic model called the Hidden Markov Model for denoising and prove the theorems involved. We make the algorithm through the process of limiting the theory in general space to finite space. In section4, as applications, noise is classified into 3 types and models are applied to each.이 논문에서는 회귀 모델과 함수 분해 방법을 이용하여 시그널의 노이즈를 제거하는 알고리즘을 다룬다. 1장에서는 선형 회귀 모델인 최소자승법을 소개하고 웨이트의 최적화된 형태를 제시한다. 또한 실제 시그널을 처리할 때 발생하는 과적합 등의 문제점을 해결하기 위한 정규화 항을 제안한다. 2장에서는 단시간 푸리에변환과 웨이블렛 변환을 다룬다. 웨이블렛의 생성으로부터 그 특징을 파악하고 L_2 함수들을 분해한다. 3장에서는 은닉 마르코프 모델을 소개하고 일반적인 공간에서의 정리들을 증명한다. 이를 유한 공간으로 제한하여 노이즈 제거를 위한 알고리즘을 만든다. 4장에서는 노이즈 종류를 3가지로 나누어 각 모델을 적용하고 그 결과를 나타낸다.1 Linear Regression Models 2 Localized Methods 2.1 Fourier Time-Frequency Methods 2.2 Wavelet Transform and Filter Banks 3 Hidden Markov Model 3.1 Markov Processes and Hidden Markov Model 3.2 Filtering, Smoothing, and Prediction Recursions 3.3 Finite State Space 4 Applications 4.1 Echo 4.2 Abrupt Noise 4.3 Gaussian NoiseMaste

Isolation of functional marine natural products from two tropical marine sponges

Tropical marine sponges are known to be one of the richest source of biologically active compounds, which prompted us to prepare the library of extracts of sponges from federated states of Micronesia and examine the biological activity of those. One of the results which seemed to be promising was that of adenosine receptor (AR) binding activity, which have a broad therapeutic potential such as sedarive, cardioprotective agent, modulator of renal fuction and etc. Chemical analysis of the selected sponge led to the isolation of known halisulfates, of which the AR binding activities are under investigations. Another sponge, identified as Chondrosia sp., which also came from Micronesia, was found out to contain psammaplysin analogs, which is known to exhibit potent antimalarial activities, by proton NMR of the crude extract. Throught the chemical investigations, psammplysin and bromotyrosine derivatives with novel structures and high cancer cell growth inhibitory activity were obtained.of those. One of the results which seemed to be promising was that of adenosine receptor (AR) binding activity, which have a broad therapeutic potential such as sedarive, cardioprotective agent, modulator of renal fuction and etc. Chemical analysis of the selected sponge led to the isolation of known halisulfates, of which the AR binding activities are under investigations. Another sponge, identified as Chondrosia sp., which also came from Micronesia, was found out to contain psammaplysin analogs, which is known to exhibit potent antimalarial activities, by proton NMR of the crude extract. Throught the chemical investigations, psammplysin and bromotyrosine derivatives with novel structures and high cancer cell growth inhibitory activity were obtained.1

Isolation of Bromopyrrole Alkaloids from the Tropical Marine Sponge Stylissa Flabelliformis

In the course our research for the discovery of bioactive substances from marine sponges collected from Chuuk, Federated State of Micronesia, we have encountered a sponge Stylissa flabelliformis. We have isolated sixteen known bromopyrrole alkaloids twelve oroidin derivatives and four bromopyrrole carboxylic acid analogs. Structures were elucidated based on NMR spectroscopy and mass spectrometry analysis.alkaloids twelve oroidin derivatives and four bromopyrrole carboxylic acid analogs. Structures were elucidated based on NMR spectroscopy and mass spectrometry analysis.2

Adenosine receptor ligands from the tropical marine sponge

Adenosine receptors (AR) have a broad therapeutic potential such as sedative, cardioprotective agent, modulator of renal function, etc. On the basis of AR binding activity screening, one of 196 tropical marine sponges was chosen for further study. In the course of our search for bioactive substances, four known halisulfates have been isolated. Investigations of AR binding activity of isolated compounds are in progress.ther study. In the course of our search for bioactive substances, four known halisulfates have been isolated. Investigations of AR binding activity of isolated compounds are in progress.2

해양미생물 및 효소를 활용한 노닐페놀 제거 기술 개발

한국해양과학기술

Biochemical Applications of Metabolome from Marine Organism

한국해양과학기술

해면을 이용한 항생제 내성 유발 단백질인 β-lactamase에 대한 저해제 발굴

한국해양과학기술