University of Fukuchiyama

Max-plus algebra is a semiring with two operations: addition ⊕:=max and multiplication ⊗:=+ . The definition of the max-plus algebraic determinant is equivalent to the assignment problem on a bipartite graph. %This study presents a new expression of the max-plus algebraic determinant. Since the assignment problem has a formulation as linear programming, the duality theorem induces the minimization problem that attains the same optimal value as the assignment problem. We translate this dual problem in terms of max-plus algebraic operation and obtain another expression for the max-plus algebraic determinant. For the determinant of the product of max-plus square matrices, we have only the inequality det(P⊗Q)≥detP⊗detQ , and a known sufficient condition for the equality is given by the condition for det(P⊗Q) . Exploiting the duality theorem for the determinant, we derive a necessary and sufficient condition for the equality. Our criterion only needs the optimal assignments corresponding to detP and detQ but does not require to compute det(P⊗Q) beforehand.

Abstract Background and Aims Estimating the time required for tree root systems to reach deep soils (> 1 m) and elucidating the characteristics of soil properties and fungi associated with deep roots are crucial for understanding tree establishment in harsh coastal environments. This study aimed (1) to determine the downward elongation rate of Pinus thunbergii taproots using tree-ring analysis and (2) to explore the relationships among deep roots, deep-soil properties, and fungal associations. Methods Annual growth rings of taproots in a coastal forest in Japan were analyzed using a cross-dating procedure. Soil physicochemical properties were assessed, and root-associated fungi in deep soils were identified by DNA sequencing. Results Taproot growth followed a sigmoid function; trees with a larger stem diameter at breast height (DBH) had greater total taproot depths. Taproot elongation of the tree with the largest DBH, located at a site with the coarsest gravel, did not slow even within deep gravel horizons. Fine soils in deep horizons had C and N concentrations comparable to or higher than surface horizons, and soil C:N ratios correlated positively with taproot elongation rates. DNA sequencing of fine roots revealed the presence of endophytic and ectomycorrhizal fungi with potential saprotrophic functions. Conclusion Taproot downward elongation dynamics appear to depend on aboveground tree characteristics and soil properties. Root detritus generated through friction with gravel likely supplies C and N to deep soils, supporting sparse saprotrophic fungi. These findings underscore the importance of deep root–soil–fungi interactions in supporting tree establishment in nutrient-poor coastal environments.

A Software Bill of Materials (SBOM) is becoming an essential tool for effective software dependency management. An SBOM is a list of components used in software, including details such as component names, versions, and licenses. Using SBOMs, developers can quickly identify software components and assess whether their software depends on vulnerable libraries. Numerous tools support software dependency management through SBOMs, which can be broadly categorized into two types: tools that generate SBOMs and tools that utilize SBOMs. A substantial collection of accurate SBOMs is required to evaluate tools that utilize SBOMs. However, there is no publicly available dataset specifically designed for this purpose, and research on SBOM consumption tools remains limited. In this paper, we present a dataset of SBOMs to address this gap. The dataset we constructed comprises 46 SBOMs generated from real-world Java projects, with plans to expand it to include a broader range of projects across various programming languages. Accurate and well-structured SBOMs enable researchers to evaluate the functionality of SBOM consumption tools and identify potential issues. We collected 3,271 Java projects from GitHub and generated SBOMs for 798 of them using Maven with an open-source SBOM generation tool. These SBOMs were refined through both automatic and manual corrections to ensure accuracy, currently resulting in 46 SBOMs that comply with the SPDX Lite profile, which defines minimal requirements tailored to practical workflows in industries. This process also revealed issues with the SBOM generation tools themselves. The dataset is publicly available on Zenodo (DOI: 10.5281/zenodo.14233414).

The scintillating grid illusion induces the phenomena of disappearance and scintillation. However, it is unclear in which peripheral region these phenomena occur. This study aimed to investigate the spatial properties of disappearance and scintillation phenomena in the scintillating grid illusion. In Experiment 1, participants binocularly observed a single-unit scintillating grid illusion and responded whether a white disk and illusory blackness were perceived. As a result, the perceptual region of the white disk was larger in the horizontal direction than in the vertical direction, as well as the perceptual region of the illusory blackness. This result indicates that both perceptual regions have spatial anisotropy. In Experiment 2, the same task as in Experiment 1 was performed with monocular viewing. The results did not exactly reject spatial anisotropy in monocular vision, regardless of the perceptual regions. This study may contribute to understanding how disappearance and scintillation phenomena coexist in the scintillating grid illusion.

Current software development takes advantage of many external libraries, but it entails security and copyright risks. While the use of the Software Bill of Materials (SBOM) has been encouraged to cope with this problem, its adoption is still insufficient. In this research, we analyzed the challenges that developers faced in practicing SBOM use by examining questions about SBOM utilization on Stack Overflow, a Q&A site for developers. As a result, we found that (1) the proportion of resolved questions about SBOM use is 15.0% which is extremely low, (2) the number of new questions has increased steadily from 2020 to 2023, and (3) SBOM users have three major challenges on SBOM tools.

本シンポジウムでは、「震災×国際」というテーマのもと、災害と心理学の関係を国際的視点から考察する。開催地である仙台は、2011年の東日本大震災で甚大な被害を受け、心理的支援やトラウマケアの実践と研究が積み重ねられてきた地域である。本シンポジウムでは、震災を経験した地域の心理学的取り組みが、国や文化の違いを超えてどのように共有・連携できるかを探ることを目的とする。登壇者には、2023年のトルコ・シリア地震で被災地支援に関わったトルコ心理学会の研究者を迎え、東日本大震災との共通点や相違点、支援の実際と課題について報告をいただく。また、日本側からも災害時の心理支援やコミュニティ再建に関する研究・実践の成果を紹介する。多様な文化・制度的背景をもつ地域の知見を共有することで、災害に対する国際的な心理支援の在り方を再考し、今後の災害発生時に向けた国際的連携の可能性を議論する。

The global population affected by heart failure is projected to reach 30 million. The number of deaths due to heart disease has surged, rising from 2 million in 2000 to 8.9 million in 2019. In Japan, the prevalence of heart failure is rapidly increasing, with the number expected to reach 1.3 million by 2030. Primary prevention is crucial to prevent heart disease. We explored the associations of heart disease incidence with findings from checkups performed a decade ago. A multivariate logistic regression analysis revealed that individuals who reported a history of stroke, history of chronic renal failure, or weight gain ≥ 10 kg since age 20 in the questionnaire-based health checkup are at high risk for developing heart disease. Additionally, those with biochemical test results from 10 years ago indicating the use of antihypertensive drugs, use of insulin injections or hypoglycemic medications, systolic hypertension, and abnormal creatinine levels also exhibited a significantly higher risk of heart disease. Conversely, individuals who identified as female, walked faster than people of the same age, drank alcohol daily, and felt refreshed upon awakening in the questionnaire-based health checkup were protected from heart disease.

With technological advancements in transmitting and storing large video files, more and more organizations are incorporating asynchronous video interviews as part of their personnel selection process. Automatic evaluation of these videos is a challenging machine learning setting because the samples are composed of time series input data but only one overall label is available. It is unclear which segments of the time series input (i.e., videos) are the most important ones for prediction. Not all nonverbal features, spoken words, and utterances contribute equally to the prediction; some segments of the videos might even introduce noise to the model. Processing all multimodal information is therefore inefficient. To address this challenge, we propose a framework to model the content of the answer via the full transcription and the speaking patterns of the interviewee via short clips. Our model learns to automatically select the most informative segment by previewing the acoustic modality using a technique called differentiable masking. The results show that our method outperforms existing approaches while being more efficient since only partial multimodal data are processed, and the interpretability of the model is enhanced.

Due to a global shortage of semiconductors, there are growing concerns about the long-term availability of legacy semiconductor chips. As a result, maintaining backstock products and using refurbished products are becoming practical maintenance strategies. In such situations, there’s a risk that “counterfeit parts” - counterfeit or imitation chips, or chips with abnormal aging characteristics - might enter the market. These counterfeit parts require technologies to identify and eliminate them. This article focuses on counterfeit parts with abnormal aging characteristics and proposes a method to detect non-invasively whether such integrated circuits (ICs) are present inside a device without opening it. The proposed method confirmed that by irradiating the device to electromagnetic waves of about 1065 MHz with an intensity of 30 dBm, ICs could be detected by accelerated testing in which an overvoltage was applied.

Tissue elongation is a fundamental morphogenetic process to construct complex embryonic structures. In zebrafish, somites rapidly elongate in both dorsal and ventral directions, transforming from a cuboidal to a V-shape within a few hours of development. Despite its significance, the cellular behaviors that directly lead to somite elongation have not been examined at single-cell resolution. Here, we describe the motion and shapes of all cells composing the dorsal half of the somite in three-dimensional space using lightsheet microscopy. We identified two types of cell movements—in horizontal and dorsal directions—that occur simultaneously within individual cells, creating a complex, twisted flow of cells during somite elongation. Chemical inhibition of Sdf1 signaling disrupted the collective movement in both directions and inhibited somite elongation, suggesting that Sdf1 signaling is crucial for this cell flow. Furthermore, three-dimensional computational modeling suggested that horizontal cell rotation accelerates the perpendicular elongation of the somite along the dorsoventral axis. Together, our study offers novel insights into the role of collective cell migration in tissue morphogenesis, which proceeds dynamically in the three-dimensional space of the embryo.