研究者詳細 - 白川　博章

Adaptive Nighttime-Light-Based Building Stock Assessment Framework for Future Environmentally Sustainable Management 査読有り Open Access

Liu, ZW; Guo, J; Zhang, RR; Ota, Y; Nagata, S; Shirakawa, H; Tanikawa, H

REMOTE SENSING 16 巻 ( 13 ) 2024年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Remote Sensing

The accumulation of artificially built environment stock during urbanization processes has been actively involved in altering the material and energy use pattern of human societies. Therefore, an accurate assessment of built environment stock can provide insights for decision makers to implement appropriate environmentally sustainable retrofitting strategies. This study presents a building stock estimation enhancement framework (BSEEF) that leverages nighttime light (NTL) to accurately assess and spatially map building stocks. By innovatively integrating a region classification module with a hybrid region-specified self-optimization module, BSEEF adaptively enhances the estimation accuracy across diverse urban landscapes. A comparative case study of Japan demonstrated that BSEEF significantly outperformed a traditional linear regression model, with improvements ranging from 1.81% to 16.75% across different metrics used for assessment, providing more accurate building stock estimates. BSEEF enhances environment/sustainability studies by enabling precise spatial analysis of built environment stocks, offering a versatile and robust framework that adapts to technological changes and achieves superior accuracy without extensive reliance on complex datasets. These advances will make BSEEF an indispensable tool in strategic planning for urban development, promoting sustainable and resilient communities globally.

DOI： 10.3390/rs16132495

Open Access

Dynamic analysis of carbon emissions from construction and demolition activities in Japan: Revealed by high-resolution 4D-GIS modeling 査読有り

Bai, YY; Yamashita, N; Guo, J; Nagata, S; Shirakawa, H; Tanikawa, H

JOURNAL OF ENVIRONMENTAL MANAGEMENT 360 巻 2024年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Environmental Management

To meet the 2050 decarbonization target of the global buildings and construction sector, more attention is needed to reduce carbon emissions from construction and demolition. However, current national carbon accounting studies for these activities remain limited in spatial granularity and localized applicability. This study developed a bottom-up spatiotemporal database of carbon emissions from building construction and demolition in Japan via integrating a geographic information system-based building stock model, statistical data, and survey information. Focusing on municipal-level emissions, the Logarithmic Mean Divisia Index approach was used to decompose spatiotemporal variations and identify the contributing factors. Results indicate that carbon emissions from Japan's construction and demolition activities fell by more than 50% between 2005 and 2020, largely due to declining new/demolished-to-stock ratio, suggesting a transition to a stock-based society. Central cities' reliance on carbon-intensive buildings positively contributed to spatial variations in their construction emissions, underscoring the importance of sustainable materials and timber designs. Differences between prefectures in demolition emission intensity highlighted the strategic placement of recycling facilities in key regions to curb transportation-related emissions. Overall, these findings provided data reference for local governments to devise tailored policies for managing construction and demolition emissions.

DOI： 10.1016/j.jenvman.2024.121099

将来の人口変化とインフラの退蔵化リスク

喜古響, 蛭田有希, 山下奈穂, 白川博章, 谷川寛樹

環境情報科学 53 巻 ( 1 ) 頁： 132 - 132 2024年4月

気候変動を考慮した洪水ハザードエリアに賦存する建築物ストックの将来推計

細川莉来, 蛭田有希, 山下奈穂, 白川博章, 谷川寛樹

環境情報科学 53 巻 ( 1 ) 頁： 121 - 121 2024年4月

共有社会経済経路を用いた気候変動による災害廃棄物ポテンシャル量への影響評価

平山修久, 白川博章, 山下奈穂, 谷川寛樹

土木学会論文集 80 巻 ( 26 ) 頁： n/a 2024年

記述言語：日本語出版者・発行元：公益社団法人土木学会

本研究では，社会経済シナリオであるSSP（共有社会経済経路）別の洪水氾濫解析による浸水深データを用いて，気候変動と土地利用変化による災害廃棄物ポテンシャル量への影響評価を行った．その結果，気候変動によって，1981年から2000年の基準気候と比較して，2031年から2050年では1.10〜1.30，2081年から2100年では1.06〜1.43と災害廃棄物ポテンシャル量が増大しうることを示した．また，人口分布の変化による災害廃棄物ポテンシャル量への影響について分析した結果，人口減少により気候変動による災害廃棄物ポテンシャル量は減少するが，一人当たりの災害廃棄物ポテンシャル量という災害リスクは増大しうると示した．

DOI： 10.2208/jscejj.24-26002

洪水ハザードエリアにおける建設資材ストック・フローの時空間分析

細川莉来, 永田聡太, 白川博章, 谷川寛樹

土木学会論文集 80 巻 ( 26 ) 頁： n/a 2024年

記述言語：日本語出版者・発行元：公益社団法人土木学会

洪水ハザードエリアの建設資材ストック・フローを把握することは，将来の洪水被害予測や洪水ハザードエリアの土地利用規制を検討する際に重要である．本研究では，日本全国で建築物一棟単位から建設資材ストックの推計を行い，洪水ハザードエリアの建設資材ストック・フローを明らかにした．結果，洪水ハザードエリア内の建設資材ストックは2003年から2020年にかけて増加しており，全国の建設資材ストックの約42%を占めていた．浸水深3m以上のハザードエリア内の低層木造建築物由来のストックは2020年に全国で1.95億トンであった．全国的にハザードエリア内外で建設資材ストックの更新率が同程度となった．洪水被害を受ける可能性の高い建設資材ストックが年々増加しており，建物立地を決定する際に洪水リスクが考慮されていない可能性が示された．

DOI： 10.2208/jscejj.24-26023

Paving the way to the future: Mapping historical patterns and future trends of road material stock in Japan 査読有り

Zhang, RR; Yamashita, N; Liu, ZW; Guo, J; Hiruta, Y; Shirakawa, H; Tanikawa, H

SCIENCE OF THE TOTAL ENVIRONMENT 903 巻 2023年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Science of the Total Environment

Roads are a fundamental component of societal infrastructure, whose decades-long lifespan has far-reaching implications for developmental decisions. The road construction and development have profound impacts on economic growth, social dynamics, and environmental sustainability. Therefore, comprehensive measurement of the current road material stock (MS) and the projection of expected future road scale based on regional socio-economic scenarios that can reflect unique local conditions are necessary. This study examined the historical changes and progression patterns of the road network across Japan from 1965 to 2020 through material flow and material stock analysis. By using the road MS time series, along with explanatory socioeconomic variables, several models including Autoregressive Integrated Moving Average with explanatory variables (ARIMAX), Support Vector Regression (SVR), hybrid ARIMAX-SVR, Multiple Linear Regression (MLR), Artificial Neural Networks (ANN), and Random Forest (RF) were compared. After comparison analysis, ARIMAX and hybrid ARIMAX-SVR models were employed to forecast expected road MS in each prefecture of Japan by 2050 based on national shared socioeconomic pathways (SSP) scenarios. The study found that the total road MS of Japan increased 5.5-fold over 55 years. Aggregate was the dominant material, comprising over 70 % among the four materials of the total road MS. The forecast results for each prefecture were classified into three different patterns. Expected MS in most prefectures still displayed increasing trends in the five scenarios, but the projection of road MS in eight prefectures revealed a notable downward trend across each SSP scenario. For most prefectures, SSP5 displayed the highest expected road MS, followed by SSP1. SSP3 was the scenario with the lowest MS. This approach provided a more thorough understanding of the likely evolution of road MS across different SSP scenarios and could help inform decisions for resource allocation and policy formulation concerning road infrastructure management.

DOI： 10.1016/j.scitotenv.2023.166632

下水道管渠を対象とした社会資本ストックの退蔵化リスク評価査読有り

山下奈穂, 松代竜毅, 蛭田有希, 白川博章, 谷川寛樹

環境情報科学論文集 ceis37 巻 ( 0 ) 頁： 70 - 77 2023年12月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人環境情報科学センター

<tt>近年，建築物や社会基盤施設の老朽化が課題となっており，限られた人的資源や財源によってこれら物質ストックを計画的に維持管理・更新していく必要がある。本研究では，全国の下水道管渠を例として，管渠の健全度及び人口予測に基づき将来退蔵化するリスクを検討した。推計結果から，全国の下水道管渠ストック量は</tt>2018 <tt>年に</tt>115 <tt>百万</tt>t <tt>であり，改築が必要な老朽管渠の割合はコンクリート管，塩ビ管でそれぞれ</tt>29%<tt>，</tt>13%<tt>であった。退蔵化リスクは北海道，奈良県，山口県，宮崎県，鹿児島県で高く，これらの地域では特に将来の経費回収率の低下や労働力不足を踏まえた計画的な対策が必要であると示唆された。</tt>

DOI： 10.11492/ceispapers.ceis37.0_70

都市構造物を対象とした世代間の同一性判定による建設資材ストック・フロー推計査読有り

太田裕也, 山下奈穂, 蛭田有希, 白川博章, 谷川寛樹

環境情報科学論文集 ceis37 巻 ( 0 ) 頁： 195 - 201 2023年12月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人環境情報科学センター

<tt>耐用年数を迎えた都市構造物や気候変動による自然災害の増加によって，都市に蓄積された物質ストックが将来大量に廃棄物として発生することが懸念される。都市構造物ストックの定量化は，将来の新規投入・排出フローの予測や今後の適切な維持管理計画を検討する上で重要な役割を果たす。本研究では，地理情報システムを活用し，日本全国の建築物と社会基盤施設の建設資材ストックを推計し，経時的な物質動態を明らかにした。</tt>2020 <tt>年の建築物の建設資材ストックは</tt>11,800 <tt>百万</tt>t<tt>，社会基盤施設は</tt>7,400 <tt>百万</tt>t <tt>と推計された。また，建築物の着工床面積は</tt>1 <tt>年あたり</tt>117 <tt>百万</tt>m2<tt>，滅失床面積は</tt>76 <tt>百万</tt>m2 <tt>であった。</tt>

DOI： 10.11492/ceispapers.ceis37.0_195

The Impacts of Households on Carbon Dioxide Emissions in Indonesia 査読有り国際共著

Hartono, D; Dachlan, AN; Hastuti, SH; Kartiasih, F; Saputri, NK; Kurniawan, R; Surahman, U; Goembira, F; Shirakawa, H

ENVIRONMENTAL PROCESSES-AN INTERNATIONAL JOURNAL 10 巻 ( 4 ) 2023年12月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Environmental Processes

This study aims to evaluate the direct and indirect contributions of household income and regional groups as well as their related sectors to CO2 emissions. The study utilized a semi-closed input‒output model (IOM) along with the hypothetical extraction method (HEM) that can estimate emissions from interdependency between household and production sectors. The results show: (1) The direct and indirect impacts on carbon emissions caused by the consumption of households in urban areas are 1.5 times higher than those in rural areas; (2) there is a positive correlation between household income and its contribution to emissions; (3) there is a notable contribution from high-income urban households to CO2 emissions, up to 1.4 times higher than the poorest household in urban areas and 0.6 times higher than the highest income in rural areas; and (3) the transportation and food sectors drive household-related CO2 emissions the most, while the education, culture, and recreation sectors contribute the least. Our findings indicated that to decrease household energy-related emissions, the government should improve the technology efficiency of transportation and communication as well as the food sectors. There is also a need to have different emission reduction policy designs between households based on their income level, particularly for increasing stringency of emission policies for high-income households.

DOI： 10.1007/s40710-023-00666-3

Uncovering urban transportation infrastructure expansion and sustainability challenge in Bangkok: Insights from a material stock perspective 査読有り国際共著

Khumvongsa, K; Guo, J; Theepharaksapan, S; Shirakawa, H; Tanikawa, H

JOURNAL OF INDUSTRIAL ECOLOGY 27 巻 ( 2 ) 頁： 476 - 490 2023年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Industrial Ecology

Development of transportation infrastructure that extends roads and railways in Bangkok has overlooked the negative environmental impact of construction material accumulation. To analyze the extent of this impact, we originally established road and railway's material intensity coefficients and investigated spatially explicit roadway and railway material stock (MS) for the years of 2004, 2009, 2014, 2019, and 2037, based upon the master plans’ target year. We further analyzed how MS evolution relates to the city's socio-economic indicators and CO2 emission. Significant growth is found in transportation MS during 2004–2019, and roadways particularly increased from 122 to 164 million metric tons (Mt). The master plans would require 43 and 6.55 Mt construction materials for roadway and railway extension, respectively, by 2037. More material-intensive roads (cross-provincial highways and major local roads) built to the suburbs of the cities and underground/elevated structures of the mass rapid transit system in dense urban areas will require three times the annual cement and steel consumption of that in the 2004–2019 period. Furthermore, a 2–3 fold increase in the number of registered vehicles and associated CO2 emissions during the study period have brought questions to the transportation infrastructure MS efficiency. The findings of this study will enable informed decision-making regarding the concern of resource consumption and for considering environmentally friendly approaches in urban transportation planning for Bangkok and other developing cities.

DOI： 10.1111/jiec.13342

Does Deep Learning Enhance the Estimation for Spatially Explicit Built Environment Stocks through Nighttime Light Data Set? Evidence from Japanese Metropolitans 査読有り

日本における建設資材ストック・フローの時空間分析査読有り

太田裕也, 山下奈穂, 蛭田有希, 白川博章, 谷川寛樹

環境情報科学 52 巻 ( 1 ) 頁： 120 - 120 2023年3月

滞留年数の延長による資源循環及び気候変動緩和への影響評価査読有り

藤川奈々, 山下奈穂, 蛭田有希, 白川博章, 谷川寛樹

環境情報科学 52 巻 ( 1 ) 頁： 119 - 119 2023年3月

Liu, ZW; Saito, R; Guo, J; Hirai, C; Haga, C; Matsui, T; Shirakawa, H; Tanikawa, H

ENVIRONMENTAL SCIENCE & TECHNOLOGY 57 巻 ( 9 ) 頁： 3971 - 3979 2023年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Environmental Science and Technology

Built environment stocks have attracted much attention in recent decades because of their role in material and energy flows and environmental impacts. Spatially refined estimation of built environment stocks benefits city management, for example, in urban mining and resource circularity strategy making. Nighttime light (NTL) data sets are widely used and are regarded as high-resolution products in large-scale building stock research. However, some of their limitations, especially blooming/saturation effects, have hampered performance in estimating building stocks. In this study, we experimentally proposed and trained a convolution neural network (CNN)-based building stock estimation (CBuiSE) model and applied it to major Japanese metropolitan areas to estimate building stocks using NTL data. The results show that the CBuiSE model is capable of estimating building stocks at a relatively high resolution (approximately 830 m) and reflecting spatial distribution patterns, although the accuracy needs to be further improved to enhance the model performance. In addition, the CBuiSE model can effectively mitigate the overestimation of building stocks arising from the blooming effect of NTL. This study highlights the potential of NTL to provide a new research direction and serve as a cornerstone for future anthropogenic stock studies in the fields of sustainability and industrial ecology.

DOI： 10.1021/acs.est.2c08468

What matters most to the material intensity coefficient of buildings? Random forest-based evidence from China

Zhang, RR; Guo, J; Yang, D; Shirakawa, H; Shi, F; Tanikawa, H

JOURNAL OF INDUSTRIAL ECOLOGY 26 巻 ( 5 ) 頁： 1809 - 1823 2022年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Industrial Ecology

Material intensity coefficient (MIC) is vital for material stock accounting in the field of industrial ecology. However, the categorization of MIC varies across regions especially for buildings that diverge greatly along the history and space aspect, and acquisition of MIC data and building information have always been a challenge in related studies. In this study, the state-of-art ensemble model “Random Forest” was developed on Chinese buildings to identify the impact of four building attributes (building structure, construction year, use type, and region) on MIC, and these features’ importance was further assessed by considering variable correlations. The features’ importance and their individual effects on MIC were intuitively revealed by depicting the partial dependence plots. Finally, a set of hierarchical MIC values was estimated by integrating the order of four variables’ importance and a quick MIC calculator was provided. Results showed that building structure is the most influential attribute for MIC, followed by the construction year, use type, and region, successively. The RF-based MIC values allow researchers to apply it to material stock and flow analysis by choosing a specific building feature(s) in the MIC calculator, which is (are) available in building physical inventory data. This study provides a method that could help researchers locate key influencing variables and give insights into the comparability of MIC research across regions and play an important role in developing urban mining and circular economy strategies.

DOI： 10.1111/jiec.13332

An estimate of the value of the beachfront with respect to the hotel room rates in Thailand Open Access

Somphong, C; Udo, K; Ritphring, S; Shirakawa, H

OCEAN & COASTAL MANAGEMENT 226 巻 2022年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Ocean and Coastal Management

An economic assessment for a non-market resource like sandy beaches is always a challenge for Thailand's coastal policy planners due to the lack of data availability, especially on the national scale. While beach tourism in Thailand has been an essential part of the Thai economy, the sandy beaches are probably exposed to the future sea-level rise. Therefore, the need for tourism benefits of the beaches should be conducted. The research attempted to measure the effect of sandy beach characteristics and hotel location on hotel room rates. A sample of 3319 hotel rooms across Thailand's coastal sub-districts, covering the entire sandy beaches in Thailand, was collected through a hotel-booking online database during the country's peak season. The considered variables include hotel room attributes, sandy beach characteristics, hotel locations, and coastal infrastructures. Through a hedonic price model based on geographically weighted regression analysis, the relationship between the dependent variables (hotel room rate) and the independent variables (selected beach variable) was estimated to evaluate the marginal effect and its spatial variations. The tourism benefit was calculated assuming the marginal effect of the hotel's beachfront locations on hotel price. The study suggested that the location in front of the beach raised the average hotel room rates by 13–41%. The results emphasized the significant spatial variability of the effect of beachfront location on the hotel price. In addition, the effect of beach protection structures (i.e., seawall, breakwaters, groins) on the hotel price was also investigated and implied a slight drop by 8–15% of the average price. The other sandy beach variables (such as beach length, width, and slope) effects on hotel price were also investigated. The finding of this study aims to help policymakers select and design proper adaptations to coastal erosion on tourist beaches in Thailand.

DOI： 10.1016/j.ocecoaman.2022.106272

A Scenario Simulation and the Prediction of Land Use and Land Cover Changes in Nigeria

IGHILE Eseosa Halima, SHIRAKAWA Hiroaki

Journal of Environmental Information Science 2021 巻 ( 2 ) 頁： 19 - 30 2022年5月

記述言語：英語出版者・発行元：Center for Environmental Information Science

Nigeria’s land use pattern is undergoing various modifications stemming from the changing demographic and economic characteristics, resulting in various environmental problems. As the land use system continues to experience rapid modifications, we need to investigate how the historical and future land use patterns may impact Nigeria’s sustainable use of its land resources. In this paper, we explored the characteristics of land use change and simulated future land use demand by combining system dynamics and the Future Land Use Simulation (FLUS) models. We simulated future land use demand from 2020 to 2040 under three developmental (business-as-usual (BAU), market-oriented and conservation) scenarios. The results of the scenarios show that under the BAU scenario, cultivated areas increased rapidly from 42.5% in 2020 (baseline) to 57.8% in 2040. However, in the market-oriented and conservation scenarios, cultivated land is anticipated to be 52.3% and 44.3% respectively in 2040, highlighting how varying socio-economic and land use policies affect land use change. Based on the predicted scenarios in 2040, we gained insight into how socio-economic changes affect land use patterns, which would aid in the development, optimisation, and prioritising of areas where the utmost focus is needed to reduce environmental degradation and ensure sustainable growth and development.

DOI： 10.11492/ceispapersen.2021.2_19

Application of GIS and Machine Learning to Predict Flood Areas in Nigeria Open Access

Ighile, EH; Shirakawa, H; Tanikawa, H

SUSTAINABILITY 14 巻 ( 9 ) 2022年5月

記述言語：日本語出版者・発行元：Sustainability (Switzerland)

Floods are one of the most devastating forces in nature. Several approaches for identifying flood-prone locations have been developed to reduce the overall harmful impacts on humans and the environment. However, due to the increased frequency of flooding and related disasters, coupled with the continuous changes in natural and social-economic conditions, it has become vital to predict areas with the highest probability of flooding to ensure effective measures to mitigate impending disasters. This study predicted the flood susceptible areas in Nigeria based on historical flood records from 1985~2020 and various conditioning factors. To evaluate the link between flood incidence and the fifteen (15) explanatory variables, which include climatic, topographic, land use and proximity information, the artificial neural network (ANN) and logistic regression (LR) models were trained and tested to develop a flood susceptibility map. The receiver operating characteristic curve (ROC) and area under the curve (AUC) were used to evaluate both model accuracies. The results show that both techniques can model and predict flood-prone areas. However, the ANN model produced a higher performance and prediction rate than the LR model, 76.4% and 62.5%, respectively. In addition, both models highlighted that those areas with the highest susceptibility to flood are the low-lying regions in the southern extremities and around water areas. From the study, we can establish that machine learning techniques can effectively map and predict flood-prone areas and serve as a tool for developing flood mitigation policies and plans.

DOI： 10.3390/su14095039

Open Access

Development of a web application for climate change adaptation in Thailand Open Access

Shirakawa H., Suanpaga W.

IOP Conference Series: Earth and Environmental Science 1016 巻 ( 1 ) 2022年4月

記述言語：日本語出版者・発行元：IOP Conference Series: Earth and Environmental Science

There is no doubt about the warming of the climate system, and it is widely accepted by a society that adaptation measures are important to reduce the negative impact of climate change on society. However, there are socio-economic obstacles to the promotion of climate change countermeasures. In other words, to implement climate change adaptation measures, not only the economic efficiency of the measures, but also fairness, consistency with existing policies, and cultural acceptability must be considered. Moreover, future forecasts contain uncertainty. Therefore, it is very difficult to formulate adaptation measures and consider policy priorities. The purpose of the study is to create a web application that shows the risk of natural disasters and the socioeconomic status of the region, targeting Thailand, which is one of the countries affected by climate change to solve the above problems. We basically developed web applications using freeware. As the result, the user can grasp the risk situation of natural disasters in Thailand as a whole, and grasp the industrial structure, agricultural production structure, and poverty situation in each region. This application is expected to promote understanding of the impacts of climate change among stakeholders and to support discussions on policy priorities.

DOI： 10.1088/1755-1315/1016/1/012023

Open Access