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대규모 텐서를 위한 메모리 효율적이고 확장 가능한 GPU 기반의 Tucker 분해 방법
No full textTensor decomposition, Big data, GPU, Scalable algorithm, Memory-efficient method1. Introduction 1
1.1 Motivation and objectives 1
1.2 Main contributions 6
1.3 Structure of thesis 7
2. Background 10
2.1 Notations 10
2.2 Tensor operations 11
2.2.1 Fiber and Slice 11
2.2.2 Frobenius Norm 12
2.2.3 Matricization 12
2.2.4 n-mode product 13
2.3 Tucker decomposition methods 15
2.3.1 Methods for Tucker decomposition 16
2.3.2 Differences between HOSVD and HOOI 18
2.3.3 Challenges and solutions in computing Tucker decomposition 19
2.3.4 Row-wise update rules 20
3. Large-Scale GPU-Based Tucker Decomposition Using Tensor Partitioning 22
3.1 GPUTucker 22
3.1.1 Overview of GPUTucker 22
3.1.2 Tensor partitioning technique 24
3.1.3 Optimization of tensor partitioning 27
3.1.4 GPU-based data pipeline 29
3.2 Exploitation of Multiple GPUs 35
3.2.1 Core tensor sharing scheme 35
3.2.2 Advantages of the core tensor sharing scheme 37
3.3 Space and Time Cost Analysis of GPUTucker 39
3.3.1 Space cost 39
3.3.2 Time cost 41
3.4 Experiments 44
3.4.1 Experimental setup 44
3.4.2 Comparison with SOTA methods 46
3.4.3 Varying characteristics of datasets 49
3.4.4 Varying configurations of GPUs 51
3.4.5 Varying partition parameters 52
4. A Memory-Efficient and Flexible GPU-based Tucker Decomposition 56
4.1 FLICO 56
4.1.1 Linearization of high-dimensional tensors 57
4.1.2 Ordering of tensor linearization 58
4.1.3 Eliminating redundant computations 58
4.2 Experiments 60
4.2.1 Experimental setup 61
4.2.2 Comparison with SOTA methods 62
4.2.3 Varying ordering of tensor linearization 63
5. Related work 66
5.1 Multi-threaded Tucker decomposition methods 66
5.2 Distributed Tucker decomposition methods 68
5.3 GPU-based Tucker decomposition methods 69
6. Conclusions 71DoctordCollectio
박테리아를 이용한 에틸렌-비닐 아세테이트 및 아크릴로니트릴 부타디엔 스티렌의 생분해
No full textEthylene vinyl acetate (EVA), acrylonitrile butadiene styrene (ABS), Biodegradation, Klebsiella aerogenes, Brevibacillus nitrificansThe massive accumulation of plastic waste in land or marine environments is one of the critical environmental issues worldwide. Plastic biodegradation by microorganisms, insect larvae, and enzymes has become one of the most popular solutions due to the ability of this strategy to generate environmentally benign byproducts, addressing ecological plastic waste concerns. This study evaluated the biodegradation of ethylene- vinyl acetate (EVA) and acrylonitrile-butadiene-styrene (ABS). The bacterial strain identified as Klebsiella aerogenes EM011, isolated from effective microorganisms, was involving the biodegradation of EVA plastic. The study found that K. aerogenes EM011 can survive in a carbon-free medium for 30 days using EVA films as the sole energy source, decomposing 0.65 ± 0.04% of 1 g of EVA film. The surface changes of the EVA film were detected using scanning electron microscopy (SEM) after treatment with K. aerogenes EM011. In addition, elemental modifications were detected in the imaged area of the plastic surfaces by energy-dispersive X-ray spectroscopy (EDS). Fourier-transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) analyses were conducted to detect changes in the functional groups and chemical components, elucidating alterations on the surface of the EVA films. Through these physicochemical analyses, the formation of carbonyl groups (C=O), ester groups (C-O), and hydroxyl groups (-OH) confirmed the oxidation of EVA. Furthermore, the oxidation led to the decomposition of the EVA film, resulting in changes in its thermal stability, hydrophobicity and molecular weight distribution. In term of ABS biodegradation, the bacterial strain identified as Brevibacillus nitrificans ABS-02, likewise isolated from effective microorganisms, was capable of degrading the ABS plastic film. The viability of B. nitrificans ABS-02 in carbon-free medium was asserted, as it exhibited proliferating cell growth up to 30- day cultivation period while using 0.9 ± 0.1% of the ABS plastic as the carbon source. The B. nitrificans ABS- 02 exhibited noticeable surface damage and the accumulation of oxygen in the damaged area of the ABS film surface after bacterial treatment, as monitored through SEM and EDS analyses. The spectral analyses of the ABS films treated with B. nitrificans ABS-02, including FT-IR and XPS, confirmed changes in chemical composition; with new peaks emerging for (1) the O−H group at 3800-3600 cm−1 and (2) the N−H group at 3250-3350 cm−1. The peak shift of the nitrile group (399.5 eV) to the amide group (399.7 eV) indicates the hydrolysis of acrylonitrile in the ABS polymer, resulting in the formation of the amide group. Furthermore, changes in hydrophilicity and thermal stability support the chemical composition change in ABS. These findings suggest that K. aerogenes EM011 and B. nitrificans ABS-02 play a role in accelerating the biodegradation of EVA and ABS plastics. This study provides insight into how microbes contribute to the degradation of ABS plastics.
Keywords: Ethylene vinyl acetate (EVA), acrylonitrile butadiene styrene (ABS), Biodegradation, Klebsiella aerogenes, Brevibacillus nitrificans|육상이나 해양 환경에 플라스틱 폐기물이 대량으로 축적되는 것은 전 세계적으로 중요한 환경 문제 중 하나입니다. 미생물, 곤충 유충 및 효소에 의한 플라스틱 생분해는 환경친화적인 부산물을 생성하여 환경적인 플라스틱 폐기물 문제를 해결하는 이러한 전략의
능력으로 인해 가장 널리 사용되는 방법 중 하나가 되었습니다. 본 연구에서는 에틸렌 비닐 아세테이트(EVA)와 아크릴로니트릴 부타디엔 스티렌(ABS)의 생분해를 평가했습니다.
유용 미생물액에서 분리된 Klebsiella aerogenes EM011 균주는 EVA 플라스틱의 생분해와 관련이 있습니다. 이 연구에 따르면 K. aerogenes EM011 은 EVA 필름을 유일한 에너지원으로 사용하여 무탄소 배지에서 30 일 동안 생존할 수 있으며, EVA 필름 1g 의 0.65 ± 0.04%를 분해합니다. K. aerogenes EM011 로 처리한 후 scanning electron microscopy 을 사용하여 필름의 표면 변화를 감지했습니다. 또한 energy-dispersive X-ray spectroscopy 에 의해 플라스틱 표면의 이미지 영역에서 원소 변형이 감지되었습니다. Fourier-transform infrared spectroscopy 및 X-ray photoelectron spectroscopy 분석을 수행하여 작용기 및 화학 성분의 변화를 감지하고 EVA 필름 표면의 변화를 설명했습니다. 이러한 물리화학적 분석을 통해 카르보닐기(C=O), 에스테르기(C-O) 및 하이드록실기(-OH)의 형성은 EVA 의 산화를 확인했습니다. 또한 산화는 EVA 필름의 분해로 이어져 열 안정성과 분자량 분포에 변화를 초래했습니다.
ABS 생분해 측면에서 Brevibacillus nitrificans ABS-02 균주는 유용 미생물액 에서 분리된 것과 마찬가지로 ABS 플라스틱 필름을 분해할 수 있었습니다. 무탄소 배지에서 B. nitrificans ABS02 의 생존 가능성은 ABS 플라스틱을 탄소원으로 사용하면서 30 일 배양 기간까지 증식하는 세포 성장을 보였기 때문에 입증되었습니다. B. nitrificans ABS-02 는 SEM 분석에서 ABS 필름의 허용 가능한 표면 손상을 보였습니다. EDS 분석 결과, 처리 필름 표면의 손상된 부위에서 산소 축적이 감지되었습니다. B. nitrificans ABS-02 로 처리된 ABS 필름의 FT-IR 및 XPS 데이터는 화학 조성의 변화를 확인했으며, 3800-3600 cm-1 에서 (1) O-H 그룹의 새로운 피크가, 3250-3350 cm-1 에서 (2) N-H 그룹의 새로운 피크가 나타났습니다. 니트릴기(399.5 eV)가 아미드기(399.7 eV)로 변경된 것은 ABS 폴리머에서 아크릴로니트릴이 가수분해되어 백본에 아미드기가 생성된다는 것을 나타냅니다. 또한 친수성 및 열 안정성의 변형은 ABS 의 화학 조성 변화를 뒷받침했습니다.
이러한 연구 결과는 K. aerogenes EM011 및 B. nitrificans ABS-02 균주가 각각 EVA 및 ABS 플라스틱의 생분해를 가속화하는 역할을 한다는 것을 보여줍니다.I. Introduction 1
II. Part 1. The biodegradation of ethylene vinyl acetate (EVA) by Klebsiella aerogenes EM011
2.1. Background 3
2.2. Material and Method 4
2.2.1. Preparation of EVA film for experiment and bacterial strain 4
2.2.2. Bacterial growth rate on EVA 4
2.2.3. EVA weight loss measurement 4
2.2.4. Treatment of the EVA films by the K. aerogenes EM011 strain 5
2.2.5. Field emission scanning electron microscopy 5
2.2.6. Energy-dispersive X-ray spectroscopy 5
2.2.7. Fourier-transform infrared spectroscopy 6
2.2.8. X-ray photoelectron spectroscopy 6
2.2.9. Contact angle measurements 6
2.2.10. Thermogravimetric analysis 6
2.2.11. High-temperature gel permeation chromatography analysis 7
2.2.12. Statistical analysis 7
2.3. Results 7
2.3.1. EVA degradation related to bacterial cell growth 7
2.3.2. Field emission scanning electron microscopy and Energy-dispersive X-ray spectroscopy analyses after the bacterial treatment of the EVA films 8
2.3.3. Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses after the bacterial treatment of the EVA films 10
2.3.4. Contact angle measurements after the bacterial treatment of the EVA films 12
2.3.5. Thermogravimetric analysis after the bacterial treatment of the EVA films 14
2.3.6. High-temperature gel permeation chromatography analysis after the bacterial treatment of the EVA films 15
2.4. Discussion 16
III. Part 2. The biodegradation of acrylonitrile butadiene styrene (ABS) by Brevibacillus nitrificans ABS-02
3.1. Background 19
3.2. Material and Method 20
3.2.1. Preparation of ABS film for experiment and bacterial strain 20
3.2.2. Bacterial growth rate on ABS-enriched medium as carbon source 21
3.2.3. ABS weight loss measurement 21
3.2.4. Treatment of the ABS films by the B. nitrificans ABS-02 strain 22
3.2.5. Field emission scanning electron microscopy 22
3.2.6. Energy-dispersive X-ray spectroscopy 22
3.2.7. Fourier-transform infrared spectroscopy 23
3.2.8. X-ray photoelectron spectroscopy 23
3.2.9. Contact angle measurements 23
3.2.10. Thermogravimetric analysis 23
3.2.11. Statistical analysis 24
3.3. Results 24
3.3.1. ABS degradation related to bacterial cell growth 24
3.3.2. Field emission scanning electron microscopy and Energy-dispersive X-ray spectroscopy analyses after the bacterial treatment of the ABS films 25
3.3.3. Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses after the bacterial treatment of the ABS films 27
3.3.4. Contact angle measurement after the bacterial treatment of the ABS films 30
3.3.5. Thermogravimetric analysis after the bacterial treatment of the ABS films 31
3.4. Discussion 32
IV. Conclusion 35
V. References 36
Abstract in Korean 42MasterdCollectio
Shortwave Infrared Imaging of a Quantum Dot-Based Magnetic Guidewire Toward Non-Fluoroscopic Peripheral Vascular Interventions
No full textPeripheral vascular interventions (PVIs) offer several benefits to patients with lower extremity arterial diseases, including reduced pain, simpler anesthesia, and shorter recovery time, compared to open surgery. However, to monitor the endovascular tools inside the body, PVIs are conducted under X-ray fluoroscopy, which poses serious long-term health risks to physicians and patients. Shortwave infrared (SWIR) imaging of quantum dots (QDs) has shown great potential in bioimaging due to the non-ionizing penetration of SWIR light through tissues. In this paper, a QD-based magnetic guidewire and its system is introduced that allows X-ray-free detection under SWIR imaging and precise steering via magnetic manipulation. The QD magnetic guidewire contains a flexible silicone tube encapsulating a QD polydimethylsiloxane (PDMS) composite, where HgCdSe/HgS/CdS/CdZnS/ZnS/SiO2 core/multi-shell QDs are dispersed in the PDMS matrix for SWIR imaging upon near-infrared excitation, as well as a permanent magnet for magnetic steering. The SWIR penetration of the QD magnetic guidewire is investigated within an artificial tissue model (1% Intralipid) and explore the potential for non-fluoroscopic PVIs within a vascular phantom model. The QD magnetic guidewire is biocompatible in its entirety, with excellent resistance to photobleaching and chemical alteration, which is a promising sign for its future clinical implementation. © 2024 Wiley-VCH GmbH.FALSEsciescopu
Multifarious astrocyte–neuron dialog in shaping neural circuit architecture
No full textAstrocytes are multifaceted glial cell types that perform structural, functional, metabolic, and homeostatic roles in the brain. Recent studies have revealed mechanisms underlying the diversity of bidirectional communication modes between astrocytes and neurons – the fundamental organizing principle shaping synaptic properties at tripartite synapses. These astrocyte–neuron interactions are critical for the proper functioning of synapses and neural circuits. This review focuses on molecular mechanisms that direct these interactions, highlighting the versatile roles of multiple adhesion-based paths that likely modulate them, often in a context-dependent manner. It also describes how astrocyte-mediated processes go awry in certain brain disorders and provides a timely insight on the pivotal roles of astrocyte–neuron interactions in synaptic integrity and their relevance to understanding and treating neurological disorders. © 2024 Elsevier LtdFALSEsciescopu
Controlled synthesis of branched 2D polytypic CdS quantum nanostructures
No full textColloidal two-dimensional (2D) semiconductor quantum nanostructures have attracted substantial interest owing to their atomically uniform thickness and spectrally sharp luminescence, exhibiting potential for optoelectronic and electronic device applications. Despite recent advancements in chemical synthesis enabling better control over lateral shapes and heterostructures, achieving morphological complexity in 2D semiconductor nanocrystals remains challenging. In this study, we report the controlled synthesis of branched 2D CdS quantum nanostructures, facilitating the realization of polytypism by growing zinc blende nano-domains within wurtzite-structured quantum nanoplates. The synthesized structures comprise multi-branched 2D quantum nanoplate arms with a precisely controlled thickness of ∼1.8 nm, joined at the zinc blende nano-domain junctions. The reaction conditions enable controlled variation in the length and complexity of these structures, while maintaining their sharp excitonic features of quantum-confined 2D semiconductor nanocrystals. In-situ small- and wide-angle X-ray scattering analysis, combined with spectroscopic and microscopic analyses, reveals that a discontinuous increase in thickness beyond a certain threshold is necessary to form zinc blende crystals within wurtzite nanoplates, upon which additional 2D quantum nanoplates subsequently grow. This study advances our understanding of 2D nanocrystal synthesis mechanisms and provides pathways for designing and fabricating branched 2D nanostructures with tailored properties. © 2024 Elsevier LtdFALSEscopu
Direct monitoring of generated particles in plasma enhanced chemical vapor deposition process using temperature compensating quartz crystal microbalance
No full textThe growing demand for high-density integrated circuits (ICs) necessitates robust contaminant particle monitoring systems to optimize yield management. This research introduces a quartz crystal microbalance (QCM) based monitoring system for particle generation during the plasma-enhanced chemical vapor deposition (PECVD) process. The sensor can be integrated at the foreline, thereby eliminating the need for additional sampling apparatuses. To extend the operational lifetime of the QCM, a novel bypass piping system with an orifice plate has been developed, improving its longevity by a remarkable 1800 times compared to conventional single-pipe configurations. In addition, the proposed sensor incorporates an integrated platinum-based resistance temperature detector (RTD) that corrects sensing inaccuracies arising from temperature variations during processing. This temperature compensation strategy ensures accurate and reliable particle measurements, particularly under high-temperature conditions. The efficacy of the proposed system has been experimentally validated during the PECVD of SiO2, showcasing its significant promise for improving ICs yield management. © 2025 Elsevier B.V.FALSEsciescopu
MICROCAVITY AND SENSOR BY USING THE SAME
No full text마이크로 공진기 및 이를 이용한 센서가 개시된다. 본 발명의 일실시예의 마이크로 공진기는, 원통형으로서, 제1재질의 내부 공진기와, 상기 내부 공진기의 측면 표면에 배치되고, 제1재질에 레이저 발진이 가능한 원자 또는 분자가 함유된 제2재질로 구성되는 코팅층을 포함한다
Suppressing organic cation reactivity in locally concentrated ionic liquid electrolytes for lithium metal batteries
No full textThe quest for highly stable ionic liquid electrolytes is vital for longer, safer cycling of Li-metal batteries (LMBs), given their nonflammable nature and broad electrochemical window. Locally concentrated ionic liquid electrolytes (LCILEs) have emerged by incorporating anti-solvating co-solvents to address the high viscosity and poor conductivity of Li+-concentrated ionic liquids. Although solvation and interface chemistry are crucial in determining cell performance, the impacts of organic cations in LCILEs remain overlooked. This work unravels the co-solvent-guided mediation of organic cation reactivity toward Li metal anodes. The donor number (DN) of co-solvents is found to significantly influence their local distribution within LCILEs, modulating Coulombic interactions between Li+–anion complexes and organic cations. Low DN co-solvents, such as hydrofluoroethers, hardly interact with Li+–anion complexes but dissociate and destabilize organic cations, adversely promoting organic cation decomposition at Li metal anodes. Conversely, high DN co-solvents prefer to occupy the Li+ solvation sheath, promoting organic cation–anion association and mitigating the cathodic decomposition. Suppressing the reactivity of organic cations in LCILEs is essential for proper anion-derived solid-electrolyte interphase formation and stable cycling of LMBs. The controlled reactivity of organic cations in concentrated ionic liquid electrolytes incorporating high DN co-solvent enables stable cycling of LMBs under stringent conditions, achieving 95 % capacity retention over 200 cycles. © 2024 Elsevier B.V.FALSEsciescopu
Polyelectrolyte-graphite grafted polymer composite sensors with high voltage sensitivity and output current density
No full textPoly (vinylidene fluoride) (PVDF)–based composites are highly desirable for diverse applications, including wearable devices, energy harvesting, smart skin robotics, and health monitoring devices. However, enhancing the voltage sensitivity and output current density of PVDF-based composites remains critical for their practical use in energy harvesting and wearable device applications. To enhance the voltage sensitivity and output current density, polystyrene sulfonic acid (PSSA) ionic filler, and graphite (Gr) electronic filler are incorporated into a PVDF matrix, leading to the development of a polar (β)–phase-based polymer composite sensor (PCS). The PVDF/PSSA/Gr-based PCS with an optimized blend ratio of 80/05/15 exhibits a high sensitivity of 0.6 V/N, which is nearly 105 times higher than that of the pure PVDF sensor. Due to the high ionic-electronic conduction in PCS, the 80/05/15-based PCS generates an enhanced output current density of 0.02 A/cm2 with a tapping force of 7.8 N at frequency of 0.1 Hz, which is 1.5 × 106 times higher than that of the pure PVDF sensor. After being worn on the finger, the PCS successfully detects finger bending and generates an output voltage of up to 5 V. The study demonstrates the potential of PVDF/PSSA/Gr composite–based sensors for wearable sensing and energy harvesting applications. © 2025 Elsevier B.V.FALSEsciescopu