The purpose of this study is to develop and implement a customized AI-based speaking diagnosis, learning, and assessment system, SpeakMaster, in order to overcome the lack of systematic evaluation and practice opportunities in school English speaking class. This system integrates automated speaking scoring to provide students with feedback on their speaking abilities across pronunciation, conversation, and presentation. This study adopts a design-based research methodology, demonstrating the development and implementation process. 1,451 students and eight teachers in elementary, middle, and high schools participated in the experiment. Data were collected through learning logs, teacher journals, interviews, and post-surveys. The findings indicate that the system design is appropriate for English class, promoting students’ flow in engaging speaking practice. Students showed motivation and satisfaction while teachers found the system valuable for monitoring student progress and facilitating speaking assessments. Despite the challenges of improving chatbot performance and enhancing scoring reliability, the results suggest that SpeakMaster shows potential to enhance English speaking education.

In this paper, the structural optimization and experimental validation of lightweight, high stiffness rollers for roll-to-roll(R2R) processing of lithium metal electrodes are presented. Precise dimensional control of electrode thickness below 50㎛ is essential for next-generation high energy density batteries, yet elastic recovery during rolling hinders the achievement of target specifications. To address this challenge, finite element(FE) analysis was employed to determine the optimal rolling gap and roller geometry, and the results were verified through R2R experiments. Simulations indicated that a rolling gap of 153㎛ yielded a final sheet thickness of about 49.6㎛, meeting the design requirement. Experimental results confirmed the validity of the numerical model, with thickness measurements deviating less than ±10% from FE analysis predictions. These findings demonstrate that the proposed roller design not only ensures thickness precision but also improves system efficiency, offering practical guidelines for scalable lithium metal electrode manufacturing.

High-entropy alloys (HEAs) are alloys that contain multiple principal elements, each in the range of 5–35%. HEAs exhibit excellent properties, however, even with conventional trial-and-error, high-throughput experimentation, and computational materials approaches, exploring their vast compositional space remains highly challenging. Accordingly, data-driven machine learning and generative-model-based inverse design methods are increasingly essential. In this study, we propose a generative-model-enabled HEA inverse design framework aimed at improving ultimate tensile strength (UTS). We first compiled 501 HEA data points from published literature and performed statistical analyses to understand their characteristics. Next, we tuned the hyperparameters of XGBoost and random forest (RF) models via Bayesian optimization, compared their performance with that of a deep neural network (DNN), and selected XGBoost as the optimal predictive model. In the subsequent stage, we trained a PyTorch-based variational autoencoder (VAE) on data from regions of the latent space associated with high-UTS probability. We randomly sampled 1,000 latent vectors, decoded them to generate candidate alloy compositions, and evaluated these candidates using the optimized XGB model. Finally, Shapley additive explanations (SHAP) interpretability analysis and a network plot were used to quantify the contributions and interactions of each feature variable, thereby assessing the physical plausibility of the model-suggested compositions.

WC–Mo₂C–Co cemented carbides were fabricated to investigate the effects of Mo₂C addition on microstructure and mechanical properties. Dual hard-phase design using WC and Mo₂C was employed to optimize the balance between hardness and toughness. Spark plasma sintering (SPS) was conducted at various temperatures after ball milling, and 1300 °C for 5 min was identified as the optimized sintering condition, achieving complete densification and phase stability. The addition of Mo₂C refined the microstructure by suppressing abnormal WC grain growth through preferential dissolution of Mo₂C into the Co binder. Hardness increased up to 1769 Hv30 due to grain refinement and solid-solution strengthening, while promoted η-phase formation and reduced fracture toughness.The 27Mo₂C composition exhibited the most balanced combination of hardness and toughness. These results demonstrate that controlled Mo₂C addition enables dual hard-phase strengthening and microstructure optimization in WC–Mo₂C–Co carbides for advanced cutting and forming applications.

세마글루타이드(Wegovy®), 티르제파타이드(Mounjaro®) 등 GLP-1 수용체 작용제는 최근 비만 및 제2형 당뇨병 치료에서 핵심적인 약제로 자리매김하였으나, 복용자들은 여전히 불규칙한 간식 섭취 등 생활습관 요인으로 인해 식후 혈당 스파이크를 경험한다. 본 논문은 이러한 문제 해결을 위한 문헌 기반의 개념적 식이 교육 모델을 제안 하였다. 문헌고찰 결과, 바나바잎 추출물의 주요 성분인 코로솔 산은 포도당 수송 억제 및 인슐린 감수성 개선 효과가 보 고되었으며, 렌틸콩은 저당지수 식품으로 혈당 상승 완화 및 지속적 포만감 유지에 도움을 주는 것으로 나타났다. 또한 땅콩은 단백질과 불포화지방산이 풍부하여 포만감을 증진시키고, 간식 대체식으로 활용 가능성이 높은 식품으 로 평가되었다. 이러한 과학적 근거를 종합하여, 본 연구에서는 렌틸콩 ·바나바잎·땅콩의 복합 기능을 통합한 기능성표시식품(렌 틸라 땅콩버터)을 활용한 GLP-1 사용자 맞춤형 식이 교 육 모델을 설계하였다. 본 모델은 ① 기능성표시식품을 이 용한 간식 치환 개념, ② 식품표시(라벨 리터러시) 교육 모듈, ③ 향후 검증 가능한 평가 지표 후보군(SMBG, 포 만감, 간식 치환율 등)을 포함하는 구조로 제시된다. 본 논문은 새로운 인체대상 데이터를 수집하지 않는 문 헌 기반 연구로서, 향후 IRB 승인을 거친 파일럿 연구를 통해 모델의 실제 효과를 검증할 필요가 있다. 이러한 접 근은 GLP-1 사용자들의 생활습관 개선과 기능성표시식품 제도의 활용성 제고를 통해 약물치료를 보완하는 새로운 식이 전략의 기초를 제공하며, 공중보건적 관점에서도 의 미 있는 시사점을 가진다.

목적 : 본 연구는 착용자의 몰입감과 편의성을 고려한 소형·고성능 Head-Mounted Display (HMD) 광학계를 구현하기 위해, 프리즘 기반의 비구면 광학계를 설계하고 그 성능을 분석하였다. 방법 : Code V 소프트웨어를 이용해 광학계를 설계하였으며, 설계 목표는 대각선 시야각 40°, 전체 시스템 두 께 약 11 mm, 조리개 크기 4 mm, ERF 15 mm 조건 하에서 0.01 mm 이하의 RMS 스팟 크기와 50 cycles/mm 에서 0.4 이상의 MTF 값을 확보하는 것이다. 총 10개 면으로 구성된 시스템은 3개의 프리즘과 1개의 디스플레이 로 이루어졌으며, 프리즘은 9개의 광학 면을 형성하고, 10번 면은 디스플레이 면이다. 5개의 비구면 면을 적용하였 으며, 비축 구조와 광로 접힘 기법을 통해 소형화와 고해상도를 동시에 달성하도록 구성되었다. 결과 : 최종 설계된 광학계는 중심부 스팟 크기 0.005 mm, 전체 평균 0.01 mm 이하로 유지되었으며, 50 cycles/mm 기준 MTF는 0.4를 달성하여 고주파 성능이 우수함을 입증하였다. 왜곡률은 최대 +2.8%로 확인되어 기존 연구 대비 향상된 왜곡 특성을 보였다. 광학 성능은 중심부뿐만 아니라 주변 시야에서도 안정적으로 유지되었 으며, 전체 시스템 두께는 11 mm로 소형화가 가능함을 입증하였다. 결론 : 본 연구는 프리즘과 비구면 요소만을 활용해 구조적 단순화와 광학적 고해상도를 동시에 달성한 사례로, 향후 웨어러블 디스플레이 및 초소형 AR 용 HMD 개발에 적용 가능한 경량화 설계 전략으로 활용될 수 있다.

To proceed an efficient acquisition program, a variety of factors such as acquirement of excellent weapon system, research and development of defense technology for independent national defense and efficient obtainments are needed to be considered. But present evaluation system of weapon is not enough to include them all. Therefore this study aims to design weapon evaluation system to overcome the cognitive error of decision makers and to cope with the complexity and uncertainty in national acquisition field. To accomplish the goal, the researchers derive 4 factors (compatibility of hierarchy, extensibility, compromise between cost and non-cost factors and aggregation of evaluation criteria and group) based on AHP. And the research intends to present rational weapon evaluation structure which can include national security environment to analysis and guarantee the objective setting of weights through empirical tests.

본 연구는 네트워크 분석 기법을 적용하여 색상(Color), 소재(Material), 가공기술(Technique) 간 조합을 체계적으 로 탐색하고 분석하는 것을 목적으로 한다. 한국디자인진흥원의 CMF HOW’S 아카이브 데이터를 기반으로 C–M–T 통합 네트워크를 구축하고, 이분 네트워크 분할과 투영(Projection) 분석을 통해 구조적 특성과 조합 양상을 정량적으 로 도출하였다. 중심성, 밀도, 군집 계수, 모듈러리티 지표를 활용한 결과, 색상은 다양한 소재⋅기술과 폭넓게 결합 되는 유연성을 보였고, 소재는 가공기술 선택을 제약하거나 반복적 조합을 형성하는 핵심 요소로 확인되었다. 일부 소재는 높은 중심성을 보여 다수의 색상⋅기술과 연결된 반면, 다른 소재는 제한적 적용성을 나타냈다. 또한 모듈러 리티 분석을 통해 유사한 가공 전략을 공유하는 조합군이 식별되어, 제품군별 설계 전략이나 공정 최적화로 확장될 수 있음을 시사한다. 전문가 인터뷰에서는 본 분석틀이 CMF 기획 및 실무 의사결정에서 활용 가능한 참조 지표로 평가되었으며, 향후 친환경 규제 대응, 산업군 비교, 제품군 사례 분석 등으로 확장 가능성이 제시되었다. 본 연구는 CMF 데이터를 구조 화하여 조합 경향을 객관적으로 이해하고, 디자인 실무에 적용 가능한 분석 도구를 제시한다는 점에서 학술적⋅실무 적 의의를 갖는다.

Five novel miniature bipolar radiofrequency (RF) electrode tips with distinct tip geometries (spherical, flat, square, and 45° angled) were developed to enable high-precision tissue ablation. Performance was evaluated on saline-soaked tissue, ex vivo bovine liver, and porcine muscle under consistent RF power settings. All designs produced highly localized lesions only a few millimeters across, confirming precise ablation with minimal damage to surrounding tissue. Tip geometry influenced ablation efficiency: a 45° angled tip created ~5 mm lesions at lower power (highest efficiency), whereas an ultra-fine 1.0 mm tip produced ~1 mm lesions but required higher power. These results indicate that the new bipolar RF electrodes achieve precise, localized tissue ablation with minimal surrounding tissue damage and show promise for precise lesion removal in minimally invasive surgery.

본 연구에서는 3D 스캐닝 기반의 역설계 기술과 전과정평가(Life Cycle Assessment, LCA)를 통합하여 실제 생산 공정의 특성을 반영한 디지털 모델을 구축하고 이를 기반으로 선박의 성능과 환경성을 동시에 개선하는 지속가능한 설계 방법을 제안하였다. 연구 대상 인 8m급 복합재료 소형 선박을 3D 스캐닝하여 초기 디지털 모델을 생성하였으며 이후 설계 중량과 실제 측정 중량 간의 차이를 규명하기 위해 수적층(hand lay-up) 공법의 제조 공차, 재료 겹침, 불균일한 수지 분포 등 생산 현장의 비정형적 요소를 모델에 정량적으로 반영하여 실제 제작 상태에 근접한 역설계 모델을 개발하였다. 이를 기준으로 성능 개선 요구사항을 만족시키는 최종 설계안을 도출하고 두 모델 에 대한 전과정평가를 수행하여 환경 영향을 비교 분석하였다. 그 결과 생산 공정의 특성을 고려한 역설계 모델은 실제 선박의 중량과 0.02% 이내의 오차를 보여 높은 정확도를 입증하고 이를 바탕으로 개선된 최종 설계안은 역설계 모델 대비 평균 1.94%의 환경 영향 감소 효과를 보였으며 폴리에스터 수지가 전체 환경 부하의 핵심 요인임을 정량적으로 식별하였다.

페어리드 체인 스토퍼(Fairlead Chain Stopper, FCS)는 10MW급 부유식 해상풍력 발전기에 설치하기 위해 새롭게 개발된 탈착형 계류 시스템이다. 본 연구에서는 다양한 메타모델과 입자군집최적화 알고리즘을 이용하여 FCS의 구조설계에 대한 최적설계안을 탐색하 였다. FCS의 구조설계는 선급규정 설계하중조건을 산정하여 유한요소해석을 통해 수치해석적으로 평가하였고, 수치해석모델을 최적설계 에 연계하여 적용하였다. 최적설계의 수렴 효율성을 향상시키기 위해 반응표면모델, 크리깅, 체비쇼프직교다항식, 그리고 신경망과 같은 다양한 메타모델이 사용되었다. 최적설계에서 제한조건은 설계하중조건 별 응력을 고려하였고, 주요 구조부품의 두께 치수를 이산설계변 수와 연속설계변수로 각각 적용하여 목적함수인 최소중량설계를 달성할 수 있는 최적해의 특성을 비교하였다. 최적설계 알고리즘은 이산 설계변수의 최적해 탐색이 가능한 입자군집최적화가 적용되었다. FCS의 구조설계에 대해 신경망 기반의 메타모델이 적용된 경우에 4.72% 이하의 오차율로 최적해의 결정이 가능한 것으로 확인되었다.

As a key axis of metropolitan public transport, exclusive median bus lanes (EMBLs) are facing operational limits owing to urban expansion and increased traffic demand, with queues at bus stops during peak hours causing severe delays. This study aims to empirically identify the phenomenon of queue-based delays at the stop level, that is difficult to explain using conventional capacity calculation methods, and to propose an operational strategy for its mitigation. By realistically assessing passenger inconvenience through a revised “additional passenger travel time” calculation based on bus travel, this study provides a balanced analysis of the tradeoff between system efficiency and passenger convenience, thereby contributing to the development of sustainable urban transit systems. This study compared current all-stop operations with two skip-stop scenarios in Songpa-daero, a major arterial corridor in Seoul. Using an actual bus management system and transit card data, key performance indicators including queue length, travel time, dwell time, and additional passenger travel time were analyzed. Scenario I applied an A/B service-style alternating stop operation, whereas Scenario II implemented a hybrid approach, designating hub stops at key locations. Simulation modeling was used to evaluate the system-wide impacts during peak hours. The analysis revealed that skip-stop operations had significant potential to improve EMBL performance; however, the benefits were subject to a trade-off with passenger inconvenience. Scenario I with alternating stops was most effective in reducing the queue length and overall travel time. However, it also resulted in the largest increase in additional passenger travel time calculated with the revised methodology. In contrast, Scenario II with hub stops, while showing slightly less improvement in operational efficiency, presented a more balanced outcome by mitigating the burden of additional travel time for passengers through hub stops, thereby enhancing service equity. Both scenarios showed reduced dwell times at most stops, indicating the alleviation of boarding and alighting congestion. This study confirmed that skip-stop strategies could effectively improve the operational efficiency of EMBLs by reducing queue lengths and travel times. However, the additional passenger travel time, including bus transfers, is a critical factor that must be considered. Scenario I was evaluated as superior for maximizing the operational efficiency, whereas Scenario II was a better alternative for securing a balance with passenger convenience. This study is significant because it presents an analytical framework for quantifying queue-based delays and realistically assessing passenger impact. Although limitations remain, such as not fully capturing the complex decision-making processes of actual passengers, the methodology and findings offer practical guidance for urban transport planners seeking data-driven solutions to EMBL congestion, emphasizing the importance of the passenger perspective in skip-stop strategy design.

In apartment buildings in Korea, irregular walls, such as T-, L-, and U-shaped walls, are commonly used. However, in practical design, the geometric irregularities of walls are often neglected when determining the length of the lateral confinement region. Further, although earthquake loads apply from various directions, the lateral confinement region is typically determined for the in-plane direction of the web. Thus, using finite element analysis, this study investigated the structural performance of irregular walls subjected to various loading directions. As the design parameters, wall shape, cross-sectional aspect ratio, and loading direction were addressed. According to the parametric analysis results, as the length of flange in tension increased, the lateral confinement region should be evaluated with consideration of the geometric irregularity. Further, for the L- and U-shaped walls, it is recommended to evaluate the lateral confinement region for various loading directions. Based on these results, a design method to determine the lateral confinement region of irregular walls was suggested.

This study proposes a real-time content design pipeline optimized for Unreal Engine, integrating generative AI-based image creation with AI-assisted 3D modeling tools. The pipeline aims to streamline the production of high-quality assets for real-time applications, including games and simulations. Two types of subjects were selected: a bust combining organic character features, and a stone slab characterized by planar and symmetrical structure. Multi-angle image data were first synthesized using advanced generative AI models to simulate diverse viewpoints. These were then processed using AI-enhanced photogrammetry and modeling tools to reconstruct detailed 3D meshes and extract base textures. Post-processing steps, including mesh decimation, UV unwrapping, and texture baking, were performed to ensure compatibility with Physically Based Rendering (PBR) workflows used in Unreal Engine. The final assets were successfully imported into Unreal Engine, demonstrating visual fidelity and performance suitability in a real-time environment. The study confirms the pipeline’s potential for accelerating asset development and suggests promising future directions in AI-driven digital content creation.

The number of significant issues on many welding processes are often connected to high productivity and manufacturability at low costs. The research on welding processes in the literature has reported several research activities, but there is still scope for improvement in most industrial settings. The primary goal of this research is to determine the best super-TIG welding settings to use for groove welding. First, in order to determine the quality characteristics and risks associated with them, concepts and frameworks of quality by design (QbD) which is a new standard in pharmaceutical area in order to improve drug qualities were integrated into this process optimization. Second, stepwise experimental design approaches including a factorial design as well as a response surface methodology (RSM) were customized and performed for this specific automated super-TIG welding process. Third, based on experimental design results, the optimal operating conditions with both design space (i.e., acceptable range of operating conditions) and safe operating space (i.e., safe range of operating conditions) were obtained. Finally, a case study including QbD steps, stepwise experimental design approaches, design and operating spaces, the optimal factor settings, and their association validation results was conducted for verification purposes.