기초 분리 말뚝을 이용한 지반 보강 공법 개발

Thesis(masters) --서울대학교 대학원 :건설환경공학부,2008.2.Maste

한국에서 국가의 사회감시 체계의 성격 변화에 관한 연구 : 1980년대 중반 이후를 중심으로

학위논문(석사) --서울대학교 대학원 :정치학과,2008. 8.Maste

Photochemical reductions of benzil and benzoin in the presence of triethylamine and TiO2 photocatalyst

This paper reports the photochemical reduction of benzil 1 to benzoin 2 and the reduction of 2 to hydrobenzoin 4 in deoxygenated solvents in the presence of triethylamine (TEA) and/or TiO2. Without TEA or TiO2, the photolysis of 1 resulted in very low yield of 2. The presence of TEA or TiO2 increased the rate of disappearance of 1 and the yield of 2, which were further increased considerably by the presence of water. The photoreduction of 1 to 2 proceeds through an electron transfer to 1 from TEA or hole-scavenged excited TiO2 followed by protonation. In the reaction medium of 88: 7: 2: 3 CH3CN/CH3OH/H2O/TEA with 2.5 mg/mL of TiO2, the yield of 2 was as high as 85% at 50% conversion of 1. The photolysis of 2 in homogeneous media resulted in photo-cleavage to benzoyl and hydroxybenzyl radicals, which are mostly converted to benzaldehyde. The reduction product 4 is formed in low yield through the dimerization of hydroxybenzyl radicals. The addition of TEA increased the conversion rate of 2 and the yield of 4 significantly. This was attributed to the scavenging effect of TEA for benzoyl radical to produce N,N-diethylbenzamide and the photoreduction of benzaldehyde in the presence of TEA. The ratio of (±) and meso isomers of 4 obtained from the photochemical reaction is about 1.1. This ratio is the same as that from the photochemical reduction of benzaldehyde in the presence of TEA. In the TiO2-sensitized photochemical reduction of 2, meso-4 was obtained in moderate yield. The reduction of 2 to 4 proceeds through two consecutive electron/proton transfer processes on the surface of the photocatalyst without involvement of α-cleavage. The radical 11 initially formed from 2 by one electron/proton process can also combine with hydroxy methyl radical, which is generated after hole trapping of excited TiO2 by methanol, to produce 1,2-diphenylpropenone after dehydration reaction

Biological evaluation of water quality, using macrobenthos. : 전북 무주군 남대천 지류를 대상으로

환경관리학과/석사ope

이식형 양심실 보조장치에서의 심실간공간압을 이용한 심방압의 추정 및 박출량 제어

학위논문(석사)--서울대학교 대학원 :의학과 의공학전공,2000.Maste

양방향 장단기 메모리와 합성곱 신경망에 기반한 보행자 보폭 추정 기법

학위논문(석사) -- 서울대학교 대학원 : 공과대학 항공우주공학과, 2024. 8. 박찬국.Bidirectional LSTM and CNN Based Pedestrian Stride Length Estimation Junu Park Department of Aerospace Engineering The Graduate School Seoul National University An increasing number of stride length estimation (SLE) algorithms adopt deep learning due to its ability to automatically learn complex nonlinearities in the data. However, datasets with true stride length are small in size, posing a threat to network performance with overfitting. Furthermore, the inertial sensor data collected from users are essentially time-series data with spatial features vary depending on individual walking characteristics. The variety of users and motions increases the complexity of the SLE. Therefore, to bypass the issue of a small-sized training dataset and effectively capture spatio-temporal features inherent in the data, this thesis introduces a bidirectional long short-term memory (BiLSTM) combined with a convolutional neural network (CNN) architecture, termed BiLSTM/CNN, which the author trains with proposed data augmentation method that employs random rotation matrix. Through quantitative and qualitative evaluations on three public datasets, this thesis proves that the proposed method outperforms state-of-the-art algorithms in terms of walking distance error rate and stride length error rate, achieving 2.62% and 5.60%, respectively. The results demonstrate that the BiLSTM/CNN and data augmentation method improve the generalization ability of the network for different users engaging in daily life activities and various motion modes. Keywords: Data augmentation, deep learning (DL), inertial measurement unit (IMU), pedestrian dead reckoning (PDR), stride length estimation (SLE). Student number: 2022-20811데이터의 복잡한 비선형성을 자동으로 학습할 수 있는 능력 덕분에 딥러닝 기반의 보폭 추정 알고리즘이 연구되고 있다. 그러나 정답 보폭이 포함된 데이터셋은 그 크기가 작아, 오버피팅으로 인한 네트워크 성능 저하의 가능성을 가진다. 또한 보행자로부터 수집된 관성 센서 데이터는 본질적으로 시계열 데이터이며, 신호의 공간적 특성은 보행자의 보행 특성에 따라 다양하게 변한다. 다양한 사용자와 동작은 보폭 추정의 복잡성 및 비선형성을 증가시킨다. 따라서 본 논문은 데이터셋의 크기가 작은 문제를 해결하고 데이터에 내재된 시공간적 특징을 효과적으로 추출하기 위해 양방향 장단기 메모리 네트워크와 합성곱 신경망을 결합한 네트워크 구조를 제안하며, 이 구조에서 학습 간에 랜덤 회전 행렬을 사용하는 제안된 데이터 증강 기법이 적용된다. 세 개의 오픈 데이터셋에 대한 양적 및 질적 평가를 통해, 제안 기법이 이동 거리 오차와 단일 보폭 오차 측면에서 최신 알고리즘들을 능가함을 입증하며, 각각 2.62%와 5.60%를 달성한다. 결과는 제안된 네트워크 구조 및 데이터 증강 기법이 다양한 동작 및 사용자에 대한 네트워크의 일반화 능력을 향상시킨다는 것을 보여준다.Introduction 1 1.1 Motivation 1 1.2 Objectives and contributions 3 Related Works 5 2.1 Deep learning-based pedestrian dead reckoning 5 2.2 Deep learning-based stride length estimation 6 2.3 Existing data augmentation methods 9 Pedestrian Stride Length Estimation 12 3.1 Inertial data pre-processing 12 3.2 Data augmentation 13 3.2.1 Matematical analysis 13 3.3 Network architecture 16 3.3.1 The general LSTM Structure 19 3.3.2 The general CNN structure 20 3.3.3 Global average pooling layer 20 3.3.4 Proposed BiLSTM/CNN network 20 Experiments and Results 23 4.1 Datasets description 23 4.1.1 SLE dataset 23 4.1.2 WDE dataset 24 4.1.3 RoNIN dataset 25 4.2 Training setup details 25 4.3 Experimental settings 26 4.4 Evaluation metrics 27 4.5 Competing methods 27 4.5.1 CNN 28 4.5.2 LSTM 28 4.5.3 ResNet-18 28 4.6 Comparison with a LOSO strategy 29 4.6.1 Comparison in controlled scenarios 29 4.6.2 Comparison in daily life scenarios 34 4.7 Comparison with a LOMO strategy 37 4.8 Ablation study 40 Conclusion 43 5.1 Conclusion and summary 43 5.2 Future works 43 Bibliography 45 국문초록 50석

Effects of modified beta-cyclodextrins on the hydrolysis reaction of p-nitrophenyl alpha-methoxyphenylacetate

Effects of beta-cyclodextrin (beta-CD) 1 and its derivatives 2-7 on the deacylation reaction of p-nitrophenyl (R or S)-alpha-methoxyphenylacetate were studied. The beta-CD derivatives used were 6-alpha-D-glucosyl-beta-CD 2, sulfated beta-CD (7-11 sulfate groups/CD ring) 3, dimethylated beta-CD 4, carboxymethylated beta-CD (3.5 carboxymethyl groups/CD ring) 5, 2-tri(2-hydroxypropyl)-beta-CD 6, and beta-CD appended on poly(allylamine) 7. The rate constant (k(psi)(CD)) of the substrate/beta-CD complexes and the formation constants (K) of the complexes were determined from the dependence of the pseudo-first order rate constants of the deacylation reaction on the concentration of beta-CDs. The order of k(psi)(CD) for the R-enantiomer at pH 8.0 is 4 << 5 < H2O < 3 congruent to 6 < 1 congruent to 2 < 7, while that for the S-enantiomer is 4 < 5 congruent to 6 < H2O congruent to 1 congruent to 2 3 < 7: H2O denotes the rate in the absence of beta-CDs. The order of K values is 3 < 7 < 6 congruent to 2 congruent to 1 < 4 < 5. This work indicates that, though the secondary hydroxyl groups of beta-CD play critical roles in the deacylation reactions of the esters complexed with beta-CDs, the reactivity of the ester/beta-CD complexes depends highly on the nature of the substituents at the secondary face of beta-CD. It also suggests that the substrates inserted from the secondary side as well as the primary side of beta-CD of poly(allylamine)-bound beta-CD undergo the reaction by attack of amino groups on the polymer chain

Surface modification of the gate dielectric with Polydimethylsiloxane of Poly(1,5-decyloxy-naphthalene-co-bithiophene) based Organic Thin Film Transistors

Maste

Homodimerization and heteroassociation of 6-O-(2-sulfonato-6-naphthyl)-γ-cyclodextrin and 6-deoxy-(pyrene-1-carboxamido)-β-cyclodextrin

6-O-(2-Sulfonato-6-naphthyl)-γ-cyclodextrin (1) and 6-deoxy-(pyrene-1-carboxamido)-β-cyclodextrin (2) were prepared. Homodimerizations of 1 and 2 and heteroassociation between 1 and 2 were investigated by 1H NMR, circular dichroism, and fluorescence spectroscopic methods. The compounds 1 and 2 form head-to-head dimers with dimerization constants of 140 ± 50 and 270 ± 70 M -1, respectively. We also determined the association constants of 1 with β-CD as 270 ± 20 M -1 and 2 with γ-CD as 100 ± 30 M -1 from fluorescence and circular dichroism titration data, respectively. The heteroassociation between 1 and 2 was manifested in increased circular dichroism ellipticities of 2, downfield shift of the H-2 proton of the pyrene group of 2, and upfield shift of the H-5 proton of the naphthyl group of 1 upon mixing 1 and 2. The analysis of circular dichroism titration data of 2 with 1 gave the association constant as 9300 ± 1600 M -1. The NMR and circular dichroism spectra suggested that the naphthyl group of 1 is deeply included into the β-CD cavity of 2, while the pyrene group of 2 is partially inserted in the γ-CD cavity of 1 in the complex. The energy-minimized structure from molecular modeling of the complex supports this. We believe that the facile heteroassociation of two cyclodextrin derivatives having different sizes of cavity and pendant group could be utilized as a useful strategy for assembling functionalized CDs for various applications

Efficient inclusion complexation and intra-complex excitation energy transfer between aromatic group-modified β-cyclodextrins and a hemicyanine dye

A hemicyanine dye, 4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide (4-ASP) forms inclusion complexes with β-cyclodextrin (β-CD) and modified β-CDs having a sulfonaphthyl (β-CD-NS) or a pyrenyl group (β-CD-py) at the primary face. The complexation constants in water were determined by fluorescence titration and found to be 4.7 × 104 M-1 with β-CD-NS and 3.6 × 104 M-1 with β-CD-py, while it is 730 M-1 with β-CD. Compared to 4-ASP in water, the emission maximum of 4-ASP of the inclusion complexes is blue-shifted by about 20 nm, and emission intensity is higher by 6.4-fold for β-CD, 14-fold for β-CD-NS and as much as 56 fold for β-CD-py complexes. These are much greater than the 3 nm blue shift and 3.3-fold enhancement of emission intensity when the solvent medium is changed to CH3OH. Good overlap between the emission bands of β-CD-appended aromatic groups and absorption band of 4-ASP results in the excitation energy transfer from the excited aromatic groups to 4-ASP and the efficiency of the intra-complex transfer is near 100%. 1H NMR spectra and molecular modeling of the 4-ASP complexes with β-CD-NS and β-CD-py indicated that N-methyl-pyridinium moiety of 4-ASP is outside the primary face of β-CD cavity. The interaction between the N-methyl-pyridinium group and the appended aromatic groups appear to result in the high stability of the complexes. The high fluorescence intensity of 4-ASP in the complexes with β-CD-NS and β-CD-py was explained in terms of hindrance of the formation of the non-fluorescent twisted intramolecular charge transfer (TICT) states by the interaction and confinement in cavity. © 2005 Elsevier B.V. All rights reserved