Faculty Profiles - SHIRAKAWA, Hiroaki

PubMed

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 Vol. 53 ( 1 ) page： 132 - 132 2024.4

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 Vol. 53 ( 1 ) page： 121 - 121 2024.4

IMPACT ASSESSMENT OF CLIMATE CHANGE ON DISASTER DEBRIS POTENTIAL USING SHARED SOCIOECONOMIC PATHWAYS

HIRAYAMA Nagahisa, SHIRAKAWA Hiroaki, YAMASHITA Naho, TANIKAWA Hiroki

Japanese Journal of JSCE Vol. 80 ( 26 ) page： n/a 2024

Language：Japanese Publisher：Japan Society of Civil Engineers

In this study, the impact of climate change and land use change on disaster debris potential was assessed using inundation depth data from flood inundation analysis by socioeconomic scenario, SSP (Shared Socioeconomic Pathway). As a result, it was pointed out that climate change can increase the amount of disaster debris potential from 1.10 to 1.30 in 2031 to 2050 and from 1.06 to 1.43 in 2081 to 2100, compared to the 1981 to 2000 base climate. The effect of population distribution on the amount of disaster debris potential was analyzed, and it was indicated that the amount of disaster debris potential due to climate change decreases due to population decrease, however, the disaster risk in terms of the amount of disaster debris per capita can increase.

DOI： 10.2208/jscejj.24-26002

Spatiotemporal Analysis of Material Stock and Flow on Construction Sector in Flood Hazard Areas

HOSOKAWA Riko, NAGATA Sota, SHIRAKAWA Hiroaki, TANIKAWA Hiroki

Japanese Journal of JSCE Vol. 80 ( 26 ) page： n/a 2024

Language：Japanese Publisher：Japan Society of Civil Engineers

Understanding the stock and flow on construction sector in flood hazard areas is important for assessing future flood damage and considering land use regulations in flood hazard areas. This study estimated material stock and flow on construction sector at the individual building level and revealed the trends in flood hazard areas. As a result, the building stock in flood hazard areas increased from 2003 to 2020, accounting for approximately 42% of the total national building stock. Especially, the stock of non-durable low-rise wooden buildings in hazard areas with flooding depth of over 3 meters had reached over 195 million tons nationwide by 2020. It was evident that the stock turnover rate is similar both inside and outside flood hazard areas, indicating that buildings have been constructed without considering flood risk.

DOI： 10.2208/jscejj.24-26023

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

Zhang, RR; Yamashita, N; Liu, ZW; Guo, J; Hiruta, Y; Shiraka

SCIENCE OF THE TOTAL ENVIRONMENT Vol. 903 2023.12

Obsolescence Risk Assessment of Infrastructure Stocks: A Case Study of Japan's Sewer Pipes Reviewed

YAMASHITA Naho, MATSUSHIRO Tatsuki, HIRUTA Yuki, SHIRAKAWA Hiroaki, TANIKAWA Hiroki

Papers on Environmental Information Science Vol. ceis37 ( 0 ) page： 70 - 77 2023.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Center for Environmental Information Science

The aging of urban structures such as buildings and infrastructures has been getting serious in these years. Those material stocks should be appropriately maintained for a long period of time, however, budget constraints and labor shortage due to population decline seem to make the situation more difficult. This study aims to estimate the amount of Japan's sewer pipe stock and compare the obsolescence risk with combinations of soundness of the existing stock and population forecast among prefectures. As results, the amount of sewer pipe stock was estimated to be 115 million t in 2018, and the rates of aged stock requiring urgent maintenance were 29% for concrete pipes and 13% for PVC pipes, respectively. Obsolescence risk was high in Hokkaido, Nara, Yamaguchi, Miyazaki and Kagoshima, indicating that those especially need deliberate countermeasures for a long-term stock management.

DOI： 10.11492/ceispapers.ceis37.0_70

Material Stock and Flow Estimation by Identifying the Congruency of Urban Structures between Generations Reviewed

OTA Yuya, YAMASHITA Naho, HIRUTA Yuki, SHIRAKAWA Hiroaki, TANIKAWA Hiroki

Papers on Environmental Information Science Vol. ceis37 ( 0 ) page： 195 - 201 2023.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Center for Environmental Information Science

The accumulation of material stocks within cities raises concerns about the potential future generation of a significant volume of waste. That is caused by the aging of urban structures and the increasing occurrence of natural disasters caused by climate change. Quantifying urban structures stock plays an imperative role in predicting future inflows and outflows, as well as formulating appropriate maintenance and management plans. In this study, Geographic Information System (GIS) was utilized to estimate and reveal the spatiotemporal dynamics of construction material stocks in buildings and infrastructures across Japan. The estimated material stock in buildings was 11,800 million tons, while infrastructure accounted for 7,400 million tons in 2020. Moreover, the newly constructed floor area of buildings in a year was 117 million square meters, with 76 million square meters of demolished floor area over the period from 2016 to 2020.

DOI： 10.11492/ceispapers.ceis37.0_195

The Impacts of Households on Carbon Dioxide Emissions in Indonesia Reviewed International coauthorship

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

ENVIRONMENTAL PROCESSES-AN INTERNATIONAL JOURNAL Vol. 10 ( 4 ) 2023.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：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

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

Uncovering urban transportation infrastructure expansion and sustainability challenge in Bangkok: Insights from a material stock perspective Reviewed International coauthorship

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

JOURNAL OF INDUSTRIAL ECOLOGY Vol. 27 ( 2 ) page： 476 - 490 2023.4

日本における建設資材ストック・フローの時空間分析 Reviewed

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 Vol. 52 ( 1 ) page： 120 - 120 2023.3

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 Reviewed

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 Vol. 52 ( 1 ) page： 119 - 119 2023.3

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

ENVIRONMENTAL SCIENCE & TECHNOLOGY Vol. 57 ( 9 ) page： 3971 - 3979 2023.3

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 Vol. 26 ( 5 ) page： 1809 - 1823 2022.10

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

Chatuphorn Somphong, Keiko Udo, Sompratana Ritphring, Hiroaki Shirakawa

OCEAN & COASTAL MANAGEMENT Vol. 226 2022.7

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

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 Vol. 2021 ( 2 ) page： 19 - 30 2022.5

Language：English Publisher：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 Vol. 14 ( 9 ) 2022.5

Language：Japanese Publisher：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 Vol. 1016 ( 1 ) 2022.4

Language：Japanese Publisher：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