Japan Architectural Review最新文献

This study numerically investigates the removal of indoor particulate pollutants of various diameters by ventilation, a portable air cleaner, and gravitational settling using a drift-flux model within a computational fluid dynamics framework. The drift-flux model is first validated against a benchmark particle dispersion experiment, showing good agreement with measured velocity and concentration. Simulations are then conducted for an L-shaped room equipped with ceiling ventilation and a portable air cleaner placed at four locations. Particles ranging from 1 to 50 μm (particle density: 1.6 × 10³ kg/m³) are considered uniformly generated. The relative contributions of ventilation (air change rates (ACH) of 0.5 and 2), air cleaner intake (ACH of 3.15), and gravitational settling are quantified. Results show that the air cleaner dominates removal for particles smaller than 10 μm, whereas gravitational settling governs particles larger than 10 μm. Considering no surface deposition or resuspension, the cleaner placement minorly influences overall removal efficiency. A one-node model based on an equivalent ACH framework is proposed to compare its predictions with CFD results. Although the one-node model cannot represent spatial variations, it captured overall trends in particle removal. This study provides insights for evaluating particle removal strategies and optimizing air cleaner use in indoor environments.

This study aims to assess the applicability of multi-agent simulation for crowd control after large-scale events. It focuses on pedestrian pathways around a stadium in an urban area. By utilizing real-world pedestrian flow data, we investigated the parameters essential for simulation and analyzed crowd control. Consequently, we identified critical simulation parameters, such as speed–density relationships and personal distance, which produced highly accurate results across different days. In terms of congestion control, we established an acceptable congestion range based on data and illustrated that averaging peak bottleneck flows effectively alleviates congestion using the simulation.

Optimizing HVAC operation in buildings while maintaining thermal comfort and indoor air quality (IAQ) is a major challenge. This study presents a framework that combines Gaussian Process Regression (GPR) models with an exhaustive search method to improve HVAC operation. The models were trained on Building Energy Management System (BEMS) data, with key features selected using the RReliefF algorithm. The GPR models achieved high prediction accuracy, with an RMSE of 0.22°C and R² of 0.813 for indoor temperature, and an RMSE of 34.45 ppm and R² of 0.919 for CO₂ concentration. For operational improvement, the supply air volume of the Dedicated Outdoor Air Handling Unit (DAHU) was adjusted to maintain CO₂ concentration near 700 ppm, while the supply air temperature of the Air Conditioning Unit (ACU) was controlled to keep indoor temperature between 26°C–27°C. These adjustments reduced fluctuations and lowered mean values, confirming improvements in both thermal comfort and IAQ. The proposed method requires no additional sensors or complex physical models, and its low computational cost ensures feasibility on standard PC environments. Overall, the results demonstrate that combining GPR-based prediction with exhaustive search enables simultaneous enhancement of thermal comfort and IAQ, with practical applicability verified using real BEMS data.

Work engagement has gained attention as an indicator of an environment where employees are productive and can work in a lively and active manner. A questionnaire survey of employees at a company was conducted as a baseline in October 2016 and a follow-up in October 2017. We analyzed 1072 responses. Following stratification of the psychological stress status, logistic regression analysis was performed by adopting the environment of a personal workspace at baseline as an independent variable and work engagement in the follow-up as a dependent variable. In the low psychological stress group, the respondents who assessed their workspace to be enclosed demonstrated a work engagement level 2.07 (95% confidence interval [CI]: 1.24–3.48) times higher than those who assessed their workspace as open. In the high psychological stress group, the odds ratio for the participants who had frequent work-related conversations in a personal workspace was significantly higher at 3.92 (95% CI: 1.23–12.51) than for those who had a low frequency of conversation. Workplaces should achieve a balance between promoting both concentration and communication. Thus, the appropriate design of a personal workspace environment should be considered to enhance work engagement.

Super-high-rise buildings commonly utilize tuned mass dampers (TMDs) for vibration control. However, buildings with different natural periods in two horizontal directions typically require multiple TMDs, increasing weight, and costs. In this study, a bidirectional TMD (BTMD) was developed to control vibrations simultaneously in both horizontal directions of high-rise buildings with different natural periods by independently tuning natural frequencies in both directions through rotational swing and orthogonal linear oscillation of the mass component. Numerical analyses and shaking table experiments on reduced-scale building models confirmed its effectiveness in suppressing structural responses of peak and root-mean-square acceleration and displacement. The proposed BTMD offers a cost-effective and lightweight solution for enhancing the seismic resilience of high-rise buildings with different dynamic properties in two directions.

This study examines the characteristics of social interactions in public spaces within Nairobi's informal settlements, with a focus on Mukuru Kwa Njenga. In the absence of formal planning and infrastructure, road spaces—particularly residential streets and a main thoroughfare—function as the primary venues for daily interaction, economic activity, and community life. Based on field observations, structured questionnaires (70 groups, 189 individuals), and pedestrian count data, the study analyzes interaction patterns across five dimensions: group scale, spatial proximity, nature of neighborhood relationships, degree of social mixture, and level of economic activity. The findings reveal that residential streets foster diverse, cross-cutting interactions among residents of varying gender, ethnicity, religion, and origin, while the main street is characterized by more homogeneous, identity-based groupings, often tied to shared origin or kinship. This contrast reflects underlying residential patterns and economic functions. By highlighting the differentiated roles of public spaces in socially complex environments, the study contributes to a deeper understanding of how informal communities negotiate coexistence. It argues that acknowledging these spatial–social dynamics is essential for inclusive upgrading strategies and the design of shared urban spaces in informal settlements.

Weather data plays a critical role in the accuracy of Building Performance Simulations (BPS). The temporal resolution of weather data can influence the outcomes of simulation-based design and operational decisions. This study examines the impact of weather data temporal resolution on building energy and daylighting simulations. EnergyPlus is employed as the BPS engine to compare the effects of different temporal resolutions, hourly, 5-min, and 1-min weather data, on simulation accuracy, and to contrast simulation outcomes using high-resolution weather data with conventional hourly data. The results show that the resolution of weather input data has only a slight impact on annual energy consumption for heating, cooling, and lighting. However, significant discrepancies emerge at the daily level, especially during periods of rapidly changing sky conditions. The study highlights the value of high-resolution weather data for performance modeling in buildings that use responsive shading or window control systems. Most notably, on partly cloudy days, shading control performance differed by approximately 8% when comparing simulations using 1-h weather data to 5-min or 1-min data. This indicates that hourly data fails to capture rapid fluctuations in solar radiation under variable sky conditions. For applications involving dynamic controls, finer temporal resolution is essential for reliable simulation.

Continuous beam-type connections between concrete-filled steel tube columns and I-section steel beams have a disadvantage in that the area of the openings for concrete filling decreases because of the existence of continuous beams. To resolve this issue, perforations were made in the beam flanges within the connection panel to improve the concrete filling. To investigate the structural performance of continuous beam-type circular concrete-filled steel tubular beam-to-column connections with perforations in the connection panel, an experimental study was conducted using T-shaped sub-assemblage specimens. The experimental parameters considered were the presence of perforations in the flange within the connection panel and beam-fixing types. All specimens exhibited a beam-yielding failure mechanism, characterized by large hysteresis loops and a high energy absorption capacity. For the specimens with perforations in the beam flange within the connection panel, strain concentrations were observed near the perforations when a tensile force was applied to the beam flange. However, no deterioration in the hysteretic behavior owing to this factor was observed. In addition, a finite element analysis was conducted. The stress transfer mechanism within the connection panel was examined based on the results of the analyses.

This project is based on the hypothesis that the combination of visual information and environmental grades—such as airflow and temperature—in a uniform, sequential space can influence psychological responses. To explore this hypothesis, we selected the Kiyotsu Gorge Tunnel as a case study. This tunnel provides a controlled spatial environment with limited external visual stimuli and includes four viewing decks that open to the outside, allowing natural light, air, and temperature variation to enter the interior. The renovation was intended to couple visual stimuli with airflow variation, under the hypothesis that this co-variation may strengthen psychological responses. Architectural elements, including water ponds and reflective mirrors, were introduced to enhance airflow or reflection from the exterior and intensify sensory engagement. Through this combination of visual and environmental cues, the project sought to create a cohesive, immersive experience throughout the entire tunnel.

After the 2011 earthquake and nuclear accident in Japan, most residents near the powerplant evacuated, but some are now returning after decontamination. Odaka, a town ruined by this disaster, has fewer buildings now than before the disaster. The transformation that vacant lots undergo after the demolition of buildings is influenced by the structure of the town center. Since the lifting of the evacuation order, there have been efforts to use vacant lots as gardens. In addition, lots owned by absentee landowners are weeded by community associations, weeding companies, and volunteers. Residents have expanded the scope of maintenance to vacant lots that they do not own in response to changes in the town's physical environment.