GIST Scholar
Not a member yet
30271 research outputs found
Sort by
Post-Correction for Interactive Monte Carlo Denoising using the James-Stein Estimator
No full text경로추적법은 몬테카를로 광선추적법의 한 종류로, 복잡한 빛 현상을 효과적으로 시뮬레이션하여 사실적인 이미지를 생성하는데 매우 효과적이며 컴퓨터 그래픽스 연 구에서 이미지를 렌더하기 위해 널리 사용된다. 인터랙티브 렌더링은 특히 샘플 수가 제한된 상황에서 디노이징 품질과 계산 효율성 간의 균형을 맞추는 데 있어 상당한 도전 과제를 제공한다. 이를 해결하기 위해 우리는 James-Stein 추정기를 활용한 블록 단위 후처리방법을통해편향된이미지와비편향된이미지를결합함으로써공간적일관성과 경계선 보존을 강화하였다. 또한 샘플 수의 한계를 극복하기 위해 비디오 시퀀스에서의 시간 정보를 활용하였다. 이 접근법은 James-Stein 추정기의 통계적 특성을 활용하여 오류를 줄임으로써 인터랙티브 렌더링 시나리오에서의 디노이징 품질을 향상시킨다.|Path tracing, a type of Monte Carlo ray tracing is highly effective in simulating complex light phenomena to produce realistic images and it is widely used in computer graphics to render images. Interactive rendering presents significant challenges in balancing denoising quality and computational efficiency, especially with limited sample counts. To address this, we integrate a blockwise post-correction method using the James-Stein estimator enabling the combination of biased and unbiased images to enhance spatial coherence and edge preservation. To overcome the limitations of low sample counts, we leverage temporal information from video sequences. This approach demonstrates improvements in denoising quality by reducing error through the statistical properties of the James-Stein estimator in interactive rendering scenarios.MasterAbstract (English)
Abstract (Korean)
List of Contents
List of Tables
List of Figures
1 Introduction
1.1 Introduction
1.2 Motivation
2 Related work
2.1 Interactive rendering denoising
2.2 Post correction for image denoisers
3 Our Post-Correction method for Interactive Denoising using the James-Stein Estimator
3.1 Background: The James-Stein Estimator
3.2 Temporally Accumulated Variance
3.3 The James-Stein Shrinkage Factor for Post-Correction
3.3.1 Preprocessing
3.3.2 Blockwise James-Stein Combiner of Unbiased and Biased Images
3.4 Implementation
4 Results and Discussion
4.1 Results
4.2 Discussion and Limitations
5 Conclusion
References
Acknowledgement
Facile preparation of core-shell Ru@Ir/C catalyst as a bifunctional electrocatalyst for reversal-tolerant anode in polymer electrolyte membrane fuel cell
No full textA robust bifunctional electrocatalyst capable of facilitating both the hydrogen oxidation reaction (HOR) and oxygen evolution reaction (OER) is essential for addressing carbon oxidation issues at the anode during cell reversal conditions in polymer electrolyte membrane fuel cell systems. In this study, we explore a bifunctional Ru@Ir/C core-shell electrocatalyst with different Ru:Ir ratios to assess its performance in both HOR and OER. The core-shell architecture of Ru@Ir is easily fabricated via sequential methods involving the formation of Ru nanoparticles onto carbon support by a solid-state method using resonance acoustic mixing, followed by the deposition of Ir shells onto the preformed Ru core using a simple ethanol reduction technique. The line-scanning profile of the energy-dispersive spectrum in transmission electron microscopy confirms the core-shell structure of Ru@Ir/C, which consists of Ru core and Ir shell. The synthesized Ru@Ir/C showed better OER performance than Ru/C and Ir/C while demonstrating comparable HOR performance to Ir/C and Pt/C. Furthermore, the presence of the Ir shell enhances active site availability for both OER and HOR, along with improved stability attributed to the electronic effects arising from the lattice mismatch between Ru and Ir. © 2024 Elsevier B.V.FALSEsciescopu
BIASsist: Empowering News Readers via Bias Identification, Explanation, and Neutralization
No full textBiased news articles can distort readers' perceptions by presenting information in a way that favors or disfavors a particular point of view. Subtly embedded in the text, these biased news articles can shape our views daily without people even realizing it. To address this issue, we propose BIASsist, an LLM-based approach designed to mitigate bias in news articles. Based on existing research, we defined six types of bias and introduced three assistive components - identification, explanation, and neutralization - to provide a broader range of bias information and enhance readers' bias-awareness. We conducted a mixed-method study with 36 participants to evaluate the effectiveness of BIASsist. The results show participants' bias awareness significantly improved and their interest in identifying bias increased. Participants also tended to engage more actively in critically evaluating articles. Based on these findings, we discuss its potential to improve media literacy and critical thinking in today's information overload era. © 2025 Copyright held by the owner/author(s)
Programmable Colloid Assembly for Nanophotonics
No full textColloidal nanoparticles offer a versatile platform for the design of photonic materials through programmable assembly. However, translating nanoscale control into large-area, scalable fabrication remains a persistent challenge, particularly for multifunctional optical devices operating across visible and infrared regimes. This dissertation presents a strategy for programmable colloidal assembly that bridges the gap between lab-scale photonic devices and scalable manufacturing, with broad implications for structural coloration, plasmonic engineering, and radiative thermal management.
A proton-assisted electrostatic assembly process was developed to facilitate rapid, uniform deposition of charged nanoparticles onto diverse substrates. By adjusting the proton concentration in the solution, the electrostatic attraction between charged nanoparticles and the substrate can be significantly enhanced without requiring chemical modification. This method is compatible with various types of coating strategies, including roll-type, stencil printing, dip coating, all offering high-throughput, wafer-scale (or centimeter scale) transfer in seconds. Furthermore, the electrostatic nature of the assembly allows for site-selective patterning and autonomous defect healing, reinforcing its practicality in manufacturing settings.
These findings establish a scalable, substrate-adaptive, and application-oriented colloidal assembly platform, addressing pressing societal needs such as personal thermal safety, outdoor visibility in low-light or hazardous environments, and passive climate adaptation, thereby contributing to a safer and more resilient human environment. To ensure outdoor visibility in dark environments, broadband plasmonic reflectors were fabricated by vertically assembling metallic nanoparticles on metallic mirrors. By tuning interparticle gaps and substrate interactions, simultaneous structural coloration, and near-infrared (NIR) reflectance were achieved. These broadband reflectors are particularly useful for outdoor signage and safety applications, where visual and machine-readable information must coexist. These reflectors exhibited enhanced durability under ultraviolet radiation, thermal cycling, and high humidity, indicating their suitability for outdoor optical applications. This thesis further extends assembly strategy to fabricate broadband scattering, spanning from visible to near-infrared regime, in conjunction with dielectric nano/microspheres. These coatings enable selective solar reflection and mid-infrared emission, providing passive radiative cooling functionalities. A wearable demonstration on human hair confirmed the platform’s practical potential, showing measurable body temperature regulation under natural sunlight without the need for external energy input.DoctorAbstract i
List of contents iii
List of figures and Tables v
I. Introduction １
1.1. Nanophotonics １
1.2. Colloid transfer technology １１
1.3. Electrostatic assembly １６
1.4. Objective and Outline ２３
II. Proton-assisted electrostatic assembly of nanoparticles ２５
2.1 Background ２５
2.2 Bioinspired assembly concept ２８
2.3 Proton engineering in electrostatic assembly ２９
2.4 Diffusion length & Ion concentration engineering ３４
2.5 Material and geometrical compatibility ３７
2.6 Scalable electrostatic nanoparticle assembly ３９
2.7 Methods ４４
III. Broadband plasmonic reflectors ４８
3.1. Background ４８
3.2. Theoretical concept of broadband plasmonic reflectors ５０
3.3. Fabrication of plasmonic reflectors ５３
3.4. Application for outdoor reflector ５６
IV. Colorful freeform radiative coolers ５８
4.1. Background ５８
4.2. Fabrication ６６
4.3. Photonic response in multiband spectrum ７１
4.4. Radiative cooling performance ７４
V. Conclusion ７７
VI. Reference ７９
VII. Acknowledgement ９８
VIII. Curriculum Vitae ９
AI-assisted design communication in ceramic-crafts education: Investigating image generation tools for concept representation and pedagogical practice
No full textThis study examines the implementation and effectiveness of AI-assisted visualization tools in ceramic-crafts education, with a specific focus on improving design communication and feedback exchange between instructors and students. Through empirical investigation, we developed and evaluated an AI-assisted visualization tool that leverages state-of-the-art image-generation models to enhance concept articulation in ceramic design practice. Our investigation, involving 12 first-year ceramic-crafts students and nine instructors, revealed significant improvements in three key areas: design communication clarity, feedback quality, and technical vocabulary acquisition. The findings demonstrate how AI tools can effectively augment specific aspects of ceramic-crafts education, particularly in bridging the gap between conceptual design and physical implementation. We analyze the tool's impact on student learning processes, instructor feedback mechanisms, and the preservation of traditional craft practices. The study contributes to the understanding of technology integration in craft-based education by providing empirical evidence of how AI tools can enhance specific pedagogical challenges while maintaining the essential tactile and experiential aspects of ceramic crafts. Additionally, we address critical considerations for implementing AI tools within traditional craft education, including the maintenance of hands-on learning experiences and artistic authenticity. Our research provides practical insights for ceramic-crafts educators seeking to integrate technological support while preserving fundamental craft-based teaching methodologies. © 2025 Elsevier B.V., All rights reserved.TRUEsciessciscopu
Association of Appendicular Skeletal Muscle Mass Index and Insulin Resistance With Mortality in Multi‐Nationwide Cohorts
No full textBackground: Although sarcopenia and insulin resistance are closely related, there is limited evidence regarding how they interact to influence mortality across different population groups. The purpose of this study was to examine the relationship between skeletal muscle mass and insulin resistance and its impact on mortality and cardiovascular disease risk using large-scale national data from Korea and the United States. Methods: We analysed data from the National Health and Nutrition Examination Survey (NHANES) 1999–2006 and 2011–2018 and the Korea National Health and Nutrition Examination Survey (KNHANES) 2008–2011, with mortality follow-up through to 2019. Cox regression models were used to assess the effects of muscle mass (appendicular skeletal mass index, ASMI) and insulin resistance on all-cause and major adverse cardiovascular and cerebrovascular events (MACCE)–related mortality. Mediation analysis was performed to examine direct and indirect effects. Results: The study included 8036 participants from NHANES and 14 449 from KNHANES. The sarcopenia group demonstrated a lower homeostasis model assessment for insulin resistance and better metabolic indices than the normal group despite having a higher mortality rate. Insulin resistance positively correlated with muscle mass (r = 0.203, p < 0.001 in the NHANES; r = 0.143, p < 0.001 in the KNHANES), and both insulin resistance and sarcopenia were identified as independent risk factors for all-cause and MACCE-related mortality. When the participants were categorized into four groups based on the presence or absence of insulin resistance and sarcopenia, those with both conditions exhibited the highest risk of all-cause mortality (hazard ratio [HR]: 2.30, 95% confidence interval [CI]: 1.72–3.08 in the NHANES; HR: 2.60, 95% CI: 2.14–3.16 in the KNHANES) and MACCE-related mortality among the groups (HR: 3.18, 95% CI: 1.99–5.08 in the NHANES; HR: 2.47, 95% CI: 1.66–3.69 in the KNHANES). Mediation analysis revealed that low muscle mass was associated with decreased insulin resistance but directly increased both all-cause mortality and MACCE-related mortality (NHANES: total natural direct effects [TNDE], HR: 2.08, 95% CI: 1.57–2.76; KNHANES: TNDE, HR: 1.69, 95% CI: 1.28–2.23). Conclusions: This study found that low ASMI was inversely associated with insulin resistance and positively associated with mortality risk in both cohorts. These findings, consistent across two large national studies, highlight the complex relationships between muscle mass, insulin sensitivity and mortality. Further studies are needed to assess the underlying mechanisms and clinical implications of these associations. Trial Registration: Clinicaltrials.gov ID: NCT05616013. © 2025 The Author(s). Journal of Cachexia, Sarcopenia and Muscle published by Wiley Periodicals LLC.FALSEsciescopu
Generating Training Data using Arma 3 for Battlefield Situation Recognition
No full text본 연구에서 우리는 전장 상황에 특화된 모델 훈련 데이터를 효율적으로 생성할 수 있는 프레임워크를 제안한다. 프레임워크는 먼저 Arma3 시뮬레이터를 활용하여 전쟁 시뮬레이션을 수행한 뒤, 이와 관련한 영상 및 메타 정보를 자동으로 수집한다. 다음으로 수집한 메타 정보를 바탕으로 장면 그래프 (Scene Graph)를 생성하고, 사전에 정의한 질문-답변 템플릿을 바탕으로 질문-응답 텍스트 레이블을 자동 생성하는 알고리즘을 개발하였다. 제안된 프레임워크로 생성한 데이터를 통해 대규모 비전-언어 모델인 LLaVA의 파인튜닝 가능성을 검증하였으며, 이를 통해 전장 상황 데이터 부족 문제를 해결하고 특화된 모델 개발을 촉진할 수 있음을 확인하였다.FALSEkc
Hyperbolic dispersion and negative refraction in a periodic perfect magnetic conductor and perfect electric conductor parallel-plate waveguide structure
No full textWe present a numerical demonstration that a periodic structure composed of alternating perfect magnetic conductor (PMC) and perfect electric conductor (PEC) parallel-plate waveguides (PPWs), filled with dielectric materials of permittivity ɛ1 and ɛ2, and separated by a gap h, exhibits hyperbolic dispersion and negative refraction. This phenomenon is enabled by surface waves confined at the PMC–PEC interfaces and disappears when the dielectric permittivities are equal (ɛ1=ɛ2), eliminating surface wave support. Furthermore, the hyperbolic nature of the dispersion is confirmed by simulated radiation patterns from a point dipole source embedded in the periodic structure. © 2025 Elsevier B.V., All rights reserved.TRUEsciescopu
Targeted co-delivery of IL-10 and catalase for cooperative therapeutic effect on acute kidney injury
No full textKidney disease has emerged as a significant public health concern, affecting approximately 10 % of adults worldwide. Especially, acute kidney injury (AKI) increases in-hospital morbidity and mortality. This study introduces a dual-therapeutic strategy combining interleukin-10 (IL-10), an anti-inflammatory cytokine, and catalase (CAT), a reactive oxygen species (ROS)-scavenging enzyme, for the treatment of inflammatory kidney injury. A kidney-targeting peptide-conjugated, Pluronic-based nanocarrier (K-NC) was developed to enable the co-delivery and sustained release of IL-10 and CAT. Compared to no-ligand conjugated NC, K-NC was selectively accumulated in the damaged kidneys while reducing liver accumulation. In vitro, CAT effectively reduced ROS levels in tubular epithelial cells, while IL-10 suppressed inflammatory cytokine expression and promoted M2 macrophage polarization. In vivo, co-delivery of IL-10 and CAT using K-NC resulted in significantly enhanced therapeutic effects on AKI compared to single delivery of IL-10 or CAT using K-NC (IL-10@K-NC or CAT@K-NC), or co-delivery of IL-10 and CAT using no-ligand conjugated NC (IL-10/CAT@NC) by showing reduced levels of serum creatinine and BUN, reduced reactive oxygen species, reduced pro-inflammatory cytokine expression, inhibited M1 macrophage polarization, and promoted M2 macrophage polarization in the kidney. This study not only presents a promising approach for the treatment of kidney inflammation but is also the first report demonstrating enhanced therapeutic effects through a combination of an antioxidant enzyme with an anti-inflammatory cytokine. © 2025 The AuthorsTRUEsciescopu