National Radio Research Agency

In this paper, statistical inference is used to predict a practical linear equation for determining signal loss rates over distance in a suburban over-rooftop path under both line-of-sight (LoS) and non-line-of-sight (NLoS) conditions. Unlike existing prediction equations, the proposed model provides an 80% confidence interval with the same slope as a regression equation and an appropriate intercept based on distance. Additionally, the proposed Gaussian mixture model clustering algorithm can classify unlabeled real-time measurements as either LoS or NLoS with high accuracy, significantly improving the convenience of signal measurement.

In response to the rapidly increasing spectrum demands driven by electronic warfare operations and the broader defense sector, we examined potential avenues for improving the defense spectrum management framework of the Republic of Korea through a comparative analysis with that of the United States. Through a comparative analysis of the regulatory frameworks governing defense frequency management in both countries, the research identified structural characteristics and systematic differences in the well-established U.S. model and examined how these insights could inform enhancements to Korea’s system. The findings revealed that neither country operated under a dedicated law exclusively for defense frequency management; instead, both manage defense frequencies within their general radio regulation frameworks. However, unlike Korea, the United States had institutionalized a more structured system for the medium- and long-term management of frequencies allocated to weapon systems, which had proven effective in practice. Consequently, this study suggested that Korea should move beyond simple frequency allocation and pursue improvements tailored to the diversified requirements of modern weapon systems and their frequency management needs.

Wannan bincike ya yi tsokaci ne a kan hikimar roƙo a cikin wasu waƙoƙin Kassu Zurmi, binciken ya kawo ma’anar roƙo da rabe- rabensa, da kuma hikimar saƙala roƙo a cikin waƙoƙin Kassu, domin isar da saƙo. Haka kuma, binciken ya dubi hanyoyin gudanar da bincike, da ra’in bincike da kuma bayani a kan sakamakon abin da binciken ya gano. Sai kammalawa daga ƙarshe.

Abstract Neoadjuvant chemotherapy (NACT) followed by surgical resection is increasingly becoming the standard treatment paradigm for pancreatic ductal adenocarcinoma (PDAC). However, post-surgical therapeutic strategies remain largely unguided by tumor. To address this critical gap, we performed an integrated multi-omics analysis using matched tumor specimens from the same clinical cohort (n=18 patients per group) to define how NACT reshapes stromal architecture and antitumor immunity in PDAC.Spatial transcriptomic analysis revealed pronounced NACT-induced reorganization of tumor and stromal compartments. Basal-like and classical-like tumor programs formed distinct spatial domains accompanied by heterogeneous CAF niches, including myCAF-, iCAF-, and apCAF-like regions. Although overall cellular composition was largely preserved, NACT triggered marked subtype-specific remodeling: basal-like tumors exhibited activation of inflammatory signaling, whereas classical-like tumors showed reduced KRAS signaling and epithelial-mesenchymal transition activity. In stromal compartments, myCAF-like regions displayed suppression of collagen biosynthesis and ECM organization programs, while iCAF- and apCAF-like niches retained inflammatory transcriptional states. Notably, NACT selectively increased spatial proximity between CD8⁺ T cells and classical-like tumor regions, whereas basal-like tumors remained embedded within CAF- and myeloid-enriched immune-restrictive microdomains.Proteomic profiling supported these spatial findings by demonstrating coordinated stromal reprogramming after NACT, with increased abundance of collagen- and coagulation-related proteins and reduced proliferative signatures. Cross-modal integration further revealed concordant activation of ECM remodeling pathways in CAF-rich niches and immune-modulatory programs near tumor regions.Consistently, multiplex immunohistochemistry demonstrated significantly increased infiltration of CD8⁺ cytotoxic and CD4⁺ helper T cells with enhanced proximity to malignant epithelial regions, while FOXP3⁺ regulatory T cells remained largely unchanged. Spatial immune organization was clinically relevant, as tumor proximity to activated CD8⁺ T cells predicted superior survival, whereas association with MDSC-dominant niches correlated with poor outcome.NACT therefore reshapes the PDAC microenvironment into clinically actionable spatial states, enabling post-surgical patient stratification and providing a rationale for personalized adjuvant strategies, including immunotherapy and CAF-targeted treatments strategy. Citation Format: Hyun Jung Kim, Se Hui Jeong, Sujie Lee, Jung Kyoon Choi, In Kyong Shim, Kyung-Gon Kim, Seung Mo Hong, Woohyung Lee, Do-hyun Park, Seung-Jae Myung, Chanho Park, Seo Hye Park, Dongjoo Lee, Song Cheol Kim. Neoadjuvant chemotherapy induces clinically distinct spatial remodeling of the tumor microenvironment in PDAC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(8_Suppl):Abstract nr LB477.

Abstract Introduction: Trastuzumab deruxtecan (T-DXd) is an antibody-drug conjugate (ADC) that is effective for both HER2-positive and HER2-low metastatic breast cancers (MBC). While correlation between HER2 expression levels and response to T-DXd was identified, effective biomarkers and mechanisms of sensitivity or resistance remain elusive, partly due to complex pharmacokinetics of T-DXd. Our goal is to delineate spatial transcriptomic (ST) features which is associated with therapeutic response and resistance to T-DXd. Methods: We performed ST with the 10x Genomics Visium HD on formalin-fixed paraffin-embedded tumor tissues from patients with MBC treated with T-DXd. Responders to T-DXd were defined as patients who experienced objective response or stable disease for more than 6 months, and non-responders were defined as otherwise. Fragments of pre-treatment biopsy samples from patients classified as responders were designated as "sensitive fragment” while that of pre-treatment biopsy samples from non-responders or post-progression biopsy samples from responders were defined as “resistant fragment”. Various transcriptome analyses were performed including the compartment modeling-based methods for estimating antibody and payload concentrations from T-DXd pharmacokinetic profiles. Results: A total of 20 tumor tissues from 13 patients were available including matched pre- and post-treatment biopsied in 5 patients. After quality check, 11 T-DXd-sensitive (19 fragments) and 7 resistant tissue samples (27 fragments) were included for analysis. Utilizing autocorrelation-related indices, spatial heterogeneity of ERBB2 gene expression influenced outcomes, with more dispersed ERBB2 gene expression distributions by cancer cells correlating with improved response. In HER2-positive tumors, resistant fragments showed downregulation of ERBB2 gene expression and activation of PI3K and EGFR pathways, with autocrine amphiregulin-EGFR signaling emerging as a candidate resistance mechanism. In HER2-low tumors, resistance was notably associated with pharmacokinetic barriers: resistant fragments exhibited increased cancer-vessel distance, reduced colocalization of ERBB2 expression with cathepsin linker-cleaving enzymes and diminished predicted tumor-to-non-tumor payload concentration ratio. Exploratory longitudinal analyses of paired pre- and post-treatment samples revealed temporal increases in vessel-cancer distance at resistance. Conclusion: These findings highlight potential determinants of T-DXd efficacy. Our study demonstrates the utility of ST for uncovering ADC response mechanisms in clinical samples and potential novel therapeutic strategies. Citation Format: Changhee Park, Minki Choi, Jiwon Koh, Sungwoo Bae, Hongyoon Choi, Kwon Joong Na, Dae-Won Lee, Kyung-Hun Lee, Han Suk Ryu, Seock-Ah Im. Spatial transcriptomics uncovers pharmacokinetic barriers and tumor-intrinsic determinants of resistance to trastuzumab deruxtecan in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 1211.

Oscillation assessment is gaining importance in modern power systems with high penetration of inverter-based and nonlinear resources. However, the lack of a reliable and complete inverter-based black-box model significantly limits the applicability of eigenvalue-based analysis. To address this limitation, this paper introduces an oscillation stability assessment framework that provides a generalized approach to analyzing oscillatory behavior. The proposed stability assessment independently applies impedance-based analysis and time-domain simulations with modeling of data-center load patterns. The framework is applied to a data-center siting scenario, enabling the simultaneous assessment of transient stability and oscillatory behavior across multiple operating conditions. Simulation results based on data-center load patterns indicated that the active-power variability induced by data-center operations cannot be fully accommodated by the power grid, highlighting the necessity of enforcing active-power ramp-rate limits to prevent oscillations when integrating data centers into the power system. By jointly leveraging impedance-based stability analysis and time-domain trajectories, the proposed framework provides a computationally tractable and physically interpretable assessment of oscillation stability, thereby supporting secure operation of large-scale power systems.