• Journal of Advanced Navigation Technology
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• v.27 no.2
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• pp.228-234
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• 2023

As the increasing demand for high-quality software, there is huge requiring for quality certification of international standards, industrial functional safety (IEC 61508), automotive (ISO 26262), embedded software guidelines for weapon systems, etc., in the industry. Software companies are very difficult to systematically acquire the quality certification in terms of cost and manpower of Startup, venture small-sized companies. For their companies one test case automatic generation is considered as a core technique to evaluate or improve software quality. This paper proposes a test case automatic generation method based on the design decision table for system and software design verification. We apply the proposed method with OMG's standard techniques of metamodel and model transformation for automatically generating test cases. To do this, we design the metamodels of design decision table (Model) and test case document (Text) and define model transformation to automatically generate test cases, which will expect to easily work MC/DC coverage.

• Journal of the Society of Disaster Information
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• v.20 no.2
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• pp.419-429
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• 2024

Purpose: To enhance the non-combustibility of fire protection piping insulation and improve the heat resistance of smoke extraction duct insulation, I plan to verify the suitability of AES insulation materials for these applications through performance testing. Method: The non-combustibility, heat resistance, and thermal insulation performance of AES insulation materials will be verified through various tests. Result: According to the 'Standards for Flame Retardancy and Fire Spread Prevention of Building Finishing Materials,' the results of non-combustibility and gas toxicity tests confirmed the non-combustible properties. The standard fire resistance tests verified the fire resistance performance. Additionally, the thermal insulation performance was confirmed through building insulation tests. Conclusion: As the performance tests on AES inorganic insulation materials have proven their noncombustibility, fire resistance, and thermal insulation performance, these materials are considered a viable alternative for improving fire spread prevention in buildings.

• Korean Journal of Radiology
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• v.21 no.10
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• pp.1150-1160
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• 2020

Objective: To describe the experience of implementing a deep learning-based computer-aided detection (CAD) system for the interpretation of chest X-ray radiographs (CXR) of suspected coronavirus disease (COVID-19) patients and investigate the diagnostic performance of CXR interpretation with CAD assistance. Materials and Methods: In this single-center retrospective study, initial CXR of patients with suspected or confirmed COVID-19 were investigated. A commercialized deep learning-based CAD system that can identify various abnormalities on CXR was implemented for the interpretation of CXR in daily practice. The diagnostic performance of radiologists with CAD assistance were evaluated based on two different reference standards: 1) real-time reverse transcriptase-polymerase chain reaction (rRT-PCR) results for COVID-19 and 2) pulmonary abnormality suggesting pneumonia on chest CT. The turnaround times (TATs) of radiology reports for CXR and rRT-PCR results were also evaluated. Results: Among 332 patients (male:female, 173:159; mean age, 57 years) with available rRT-PCR results, 16 patients (4.8%) were diagnosed with COVID-19. Using CXR, radiologists with CAD assistance identified rRT-PCR positive COVID-19 patients with sensitivity and specificity of 68.8% and 66.7%, respectively. Among 119 patients (male:female, 75:44; mean age, 69 years) with available chest CTs, radiologists assisted by CAD reported pneumonia on CXR with a sensitivity of 81.5% and a specificity of 72.3%. The TATs of CXR reports were significantly shorter than those of rRT-PCR results (median 51 vs. 507 minutes; p < 0.001). Conclusion: Radiologists with CAD assistance could identify patients with rRT-PCR-positive COVID-19 or pneumonia on CXR with a reasonably acceptable performance. In patients suspected with COVID-19, CXR had much faster TATs than rRT-PCRs.

• Journal of the Earthquake Engineering Society of Korea
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• v.28 no.3
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• pp.129-139
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• 2024

In this study, the SBC system, a new mechanical joint method, was developed to improve the constructability of precast concrete (PC) beam-column connections. The reliability of the finite element analysis model was verified through the comparison of experimental results and FEM analysis results. Recently, the intermediate moment frame, a seismic force resistance system, has served as a ramen structure that resists seismic force through beams and columns and has few load-bearing walls, so it is increasingly being applied to PC warehouses and PC factories with high loads and long spans. However, looking at the existing PC beam-column anchorage details, the wire, strand, and lower main bar are overlapped with the anchorage rebar at the end, so they do not satisfy the joint and anchorage requirements for reinforcing bars (KDS 41 17 00 9.3). Therefore, a mechanical joint method (SBC) was developed to meet the relevant standards and improve constructability. Tensile and bending experiments were conducted to examine structural performance, and a finite element analysis model was created. The load-displacement curve and failure pattern confirmed that both the experimental and analysis results were similar, and it was verified that a reliable finite element analysis model was built. In addition, bending tests showed that the larger the thickness of the bolt joint surface of the SBC, the better its structural performance. It was also determined that the system could improve energy dissipation ability and ductility through buckling and yielding occurring in the SBC.

• Journal of the Korean Wood Science and Technology
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• v.52 no.4
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• pp.375-382
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• 2024

The study focuses on evaluating the bending creep performance of laminated veneer lumber (LVL) formwork in timber concrete composite (TCC) structures. Timber-framed construction is highlighted for its environmental benefits and seismic resistance, but limitations such as poor tensile strength and brittle failure in bending hinder its use in high-rise buildings. Wood-concrete hybrid structures, particularly those using reinforced concrete slabs with TCC floors, emerge as a potential solution. The research aims to understand the time-dependent behavior of TCC components, considering factors like wood and concrete shrinkage and connection creep. The experiment was conducted in western Japan on the TCC floor designed for use in the Kama-city Inatsuki-higashi compulsory education school. The LVL formwork, measuring 9,000 mm by 900 mm, and concrete is loaded onto it for testing. The creep test periods are examined using concrete loading. It employs a comprehensive creep analysis, adhering to Japanese standards, involving deflection measurements and regression analysis to estimate the creep coefficient. Results indicate substantial deformation after shoring removal, suggesting potential reinforcement needs. The study recommends extending test periods for improved accuracy and recognizing regional climate impacts. Overall, the research provides valuable insights into the potential of LVL formwork in TCC structures, emphasizing safety considerations and paving the way for further experimentation under varied conditions to validate structural integrity.

• Safety and Health at Work
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• v.15 no.2
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• pp.228-235
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• 2024

Background: Glove reuse poses risks, as chemicals can persist even after cleaning. Decontamination methods like thermal aeration, recommended by US OSHA, vary in effectiveness. Some studies show promising results, while others emphasize the importance of considering both permeation and tensile strength changes. This research advocates for informed glove reuse, emphasizing optimal thermal aeration temperatures and providing evidence to guide users in maintaining protection efficiency. Methods: The investigation evaluated Neoprene and Nitrile gloves (22 mils). Permeation tests with toluene and acetone adhered to American Society for Testing Materials (ASTM) F739 standards. Decontamination optimization involved aeration at various temperatures. The experiment proceeded with a maximum of 22 re-exposure cycles. Tensile strength and elongation were assessed following ASTM D 412 protocols. Breakthrough time differences were statistically analyzed using t-test and ANOVA. Results: At room temperature, glove residuals decreased, and standardized breakthrough time (SBT)₂ was significantly lower than SBT₁, indicating reduced protection. Higher temperature decontamination accelerated residual removal, with ∆SBT (SBT₂/SBT₁) exceeding 100%, signifying restored protection. Tensile tests showed stable neoprene properties postdecontamination. Results underscore thermal aeration's efficacy for gloves reuse, emphasizing temperature's pivotal role. Findings recommend meticulous management strategies, especially post-breakthrough, to uphold glove-protective performance. Conclusions: Thermal aeration at 100℃ for 1 hour proves effective, restoring protection without compromising glove strength. The study, covering twenty cycles, suggests safe glove reuse with proper decontamination, reducing costs significantly. However, limitations in chemical-glove combinations and exclusive focus on specific gloves caution against broad generalization. The absence of regulatory directives on glove reuse highlight the importance of informed selection and rigorous decontamination validation for workplace safety practices.

• Journal of Advanced Navigation Technology
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• v.28 no.4
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• pp.393-399
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• 2024

The digital map computer for advanced air vehicles (AAV) must be high-performance, lightweight, portable, and modular. It should receive data on terrain, weather, and obstacles from external modules to display digital maps accurately. This necessitates robust communication capabilities with external devices via an Ethernet interface and the ability to output digital map visuals clearly through an high-defintion multimedia Interface (HDMI) or digital visual interface (DVI) interface. This paper presents the design of both hardware and software architecture that fulfills these critical requirements for an AAV digital map system. Additionally, it establishes the minimum specifications needed and verifies the suitability of the designed digital map computer through rigorous performance measurements and testing. By ensuring these standards, the digital map computer can reliably support the complex navigational needs of AAV, enhancing operational efficiency and safety.

• Journal of Auto-vehicle Safety Association
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• v.16 no.1
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• pp.42-48
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• 2024

With a sustained increase in the number of reported registrations for two-wheeled vehicles and the simultaneous growth of the domestic two-wheeled vehicle market, fueled by the activation of contactless industries and a rising population engaging in recreational two-wheeled vehicles during the COVID-19 era, concerns regarding safety incidents and environmental issues have come to the forefront. While the regular inspection methods and environmental standards for four-wheeled vehicles are becoming more stringent for safety and environmental management, the same cannot be said for two-wheeled vehicles. As the market for two-wheeled vehicles continues to expand, there is a pressing need for improvements in the management and inspection of these vehicles. In this study, we analyze cases of non-compliance from the results of periodic inspections over the past five years, specifically focusing on illegal customizations, exhaust emissions testing, and exhaust noise results. Through this analysis, we elucidate the necessity for enhancing the inspection system for two-wheeled vehicles, drawing parallels with the inspection systems applied to conventional automobiles. The findings of this research contribute to advocating for improvements in the inspection regime for two-wheeled vehicles, addressing the growing concerns related to safety and environmental impact.

• Journal of Aerospace System Engineering
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• v.18 no.4
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• pp.70-80
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• 2024

In this study, we explore the purpose, origin, and history of thermal testing in the development of artificial satellite components. We seek to understand precisely the test variables associated with thermal vacuum and thermal cycle tests, including temperature margins and cycle counts, which may differ according to the development model. We analyze specifications detailed in standards from NASA, ESA, MIL, and others. Furthermore, given the recent surge in interest in CubeSats and nanosatellites, this paper aims to identify research trends in customizing satellite development projects according to their budget and duration.

• Advances in concrete construction
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• v.17 no.3
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• pp.135-150
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• 2024

Nano-silica's growing use in construction, known for enhancing strength and durability by reducing porosity, drives this research's significance, especially considering Ecuador's reliance on cement in construction. A comprehensive comparative study on mortars made with General Use cement and aggregates from Pifo and San Antonio quarries has been studied. It explores the impact of incorporating nano-silica in varying proportions (0.75%, 1.00%, 1.25%) on mortar properties, contrasting them with conventional and prefabricated mortars. laboratory Testing is conducted according to standards to assess both fresh and hardened state properties, and microscopic analysis reveals the optimal nano-silica proportion's effects on mortar characteristics. Results shows that Incorporating 0.75% nano-silica resulted in a 61% increase in compressive strength at 7 days and. For a nanosilica content of 1.25%, a 14% increase in compressive strength was observed at 28 days in relation to the conventional mortar and the permeability of the mortar decreased by 30% when adding 0.75% nanosilica. It discusses economic viability and provides insights through SEM and EDS analyses. Overall, it underscores nano-silica's potential to enhance mortar properties and its relevance in creating more efficient and durable construction materials.