Yoshio Kajitani
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View article: Efficient disaster damage prediction method using building point data and LTSM: a case of flood disaster
Efficient disaster damage prediction method using building point data and LTSM: a case of flood disaster Open
Accurate information on the location and use of individual buildings is essential for estimating impacts from disasters. However, even in developed countries, such data remains scarce, forcing reliance on aggregated statistics that obscure…
View article: Methodology for estimating regional production capacity loss rate in industrial sectors caused by disasters: A case study of the 2016 Kumamoto earthquakes
Methodology for estimating regional production capacity loss rate in industrial sectors caused by disasters: A case study of the 2016 Kumamoto earthquakes Open
The estimation of regional Production Capacity Loss Rate (PCLR) in industrial sectors after disasters is critical for disaster mitigation, resource allocation and restoration. Recent studies to estimate the PCLR in industrial sectors were …
View article: Long‐term flood exposure assessment using satellite‐based land use change detection and inundation simulation: A 30‐year case study of the <scp>Bangkok Metropolitan Region</scp>
Long‐term flood exposure assessment using satellite‐based land use change detection and inundation simulation: A 30‐year case study of the <span>Bangkok Metropolitan Region</span> Open
The Bangkok Metropolitan Region (BMR), located in the Chao Phraya River basin delta, is particularly vulnerable to floods, with susceptibility heightened by geographical aspects and rapid urbanization. This study aimed to assess spatiotemp…
View article: Risk-based resilience assessment framework for thermal power plants after a catastrophic seismic event
Risk-based resilience assessment framework for thermal power plants after a catastrophic seismic event Open
This paper presents a framework to assess the seismic resilience of thermal power plants, which can be applied for power shortage risk analysis during earthquakes and the subsequent recovery process. The key issue of the proposed framework…
View article: Estimation of utilitiesfor urban employment areas based on household utility models and core statistics
Estimation of utilitiesfor urban employment areas based on household utility models and core statistics Open
人口減少下における大都市圏への人口集中は,大都市の過密問題と地方の人口減少に伴う様々な問題を深刻化させている.本研究では,世帯効用モデルと独自集計した政府基幹統計に基づき,都市雇用圏別のモデル世帯の効用,および,構成要素別の影響を求めた.その結果,都市規模と求めた効用に相関は無く,大都市は所得は高いが住宅床地代や通勤時間が効用を押し下げること,特に東京の賃貸世帯の効用の偏差は負であることなどを示した.この結果は,国土交通省の都道府県別の経済的豊かさの調査結果と整合的だが,本…
View article: A framework to estimate a long-term power shortage risk following large-scale earthquake and tsunami disasters
A framework to estimate a long-term power shortage risk following large-scale earthquake and tsunami disasters Open
While power shortages during and after a natural disaster cause severe impacts on response and recovery activities, related modeling and data collection efforts have been limited. In particular, no methodology exists to analyze long-term p…
View article: Modeling economic impacts of mobility restriction policy during the COVID‐19 pandemic
Modeling economic impacts of mobility restriction policy during the COVID‐19 pandemic Open
The economic impacts of pandemics can be enormous. However, lockdown and human mobility restrictions are effective policies for containing the spread of the disease. This study proposes a framework for assessing the economic impact of vary…
View article: ASSESSING THE SOCIOECONOMIC IMPACT OF FLOOD DISASTERS USING SMART METER DATA
ASSESSING THE SOCIOECONOMIC IMPACT OF FLOOD DISASTERS USING SMART METER DATA Open
本研究では電力消費量が住民や企業の活動度を強く反映することに着目し,スマ―トメーターデータを用いた水害による社会経済活動への影響分析を試みた.具体的には,災害がない場合の電力消費を予測するモデルを構築し,観測値との差分から水害による電力消費低下量を推計するアプローチを行った.2019年の水害によって影響を受けた地域に本分析アプローチを適用した結果,電力消費量の落ち込みは発災から時間が経るにつれて回復傾向を示し,浸水が発生していないと推定された周辺地域にも間接的影響が波及して…
View article: ECONOMIC IMPACTS IN INDUSTRIAL SECTOR ON THE HEAVY RAIN EVENT OF JULY 2018 AND ITS FACTOR ANALYSIS
ECONOMIC IMPACTS IN INDUSTRIAL SECTOR ON THE HEAVY RAIN EVENT OF JULY 2018 AND ITS FACTOR ANALYSIS Open
水害による産業部門の経済被害は,浸水以外の要因も考えられる.長期のライフライン被害や運転資金の不足等の負の要因,振替生産や各種BCPの効果等の正の要因も考えられる.浸水以外の要因が経済被害に与える影響や,経済被害の内訳である復旧費用と営業利益減少額の関係については,定量的な議論が十分になされていない.本研究では,岡山県倉敷市真備地区及び広島県呉市において,平成30年7月豪雨の浸水以外の影響も踏まえ,産業部門の経済被害を推計する.既往の復旧費用率のフラジリティ曲線や売上回復曲…
View article: RECOVERY CURVE OF POST-EARTHQUAKE PRODUCTION CAPACITY CONSIDERING LIFELINE RECOVERY PERIOD —A CASE STUDY OF THE 2022 FUKUSHIMA OFFSHORE EARTHQUAKE—
RECOVERY CURVE OF POST-EARTHQUAKE PRODUCTION CAPACITY CONSIDERING LIFELINE RECOVERY PERIOD —A CASE STUDY OF THE 2022 FUKUSHIMA OFFSHORE EARTHQUAKE— Open
本稿ではライフラインの復旧期間を考慮した企業の操業能力の復旧曲線を提案した.具体的には 2022 年福島県沖の地震における被害調査データを用い,操業能力の回復過程をセミ・マルコフ過程でモデル化するとともに,ライフラインの復旧日数を用いた操業能力水準の滞在時間分布を推計し,実際の回復データと整合的なリカバリーカーブを構築した.これにより福島県沖の地震における企業の操業能力のリカバリ ー実態を明らかとした.本提案手法はライフラインの復旧日数からリカバリーカーブを推定するため,ラ…
View article: SEISMIC LANDSLIDE RISK ASSESSMENT METHOD BASED ON DISASTER PREVENTION CHART AND STABILITY SURVEY TABLES FOR DETECTING ISOLATED COMMUNITIES
SEISMIC LANDSLIDE RISK ASSESSMENT METHOD BASED ON DISASTER PREVENTION CHART AND STABILITY SURVEY TABLES FOR DETECTING ISOLATED COMMUNITIES Open
集落へのアクセス手段が断たれる孤立化を防ぐ斜面崩壊対策は重要である.本研究では斜面状況を記録した防災カルテ・安定度調査表などのデータを整備し,共分散構造分析,ロジスティック回帰分析,SMOTEによる斜面崩壊確率評価式を提案した.既往災害におけるテストデータに適用した結果,複数のデータベースや分析手法を組み合わせると,法面・自然斜面の崩壊的中率が向上することが確認できた.次に和歌山県における南海トラフ想定地震時について法面・自然斜面の崩壊確率より,緊急輸送道路の途絶確率を推定…
View article: A proposal for mutual-aid-type distributed evacuation based on residents’ evacuation intentions in a hilly and mountainous area of Japan
A proposal for mutual-aid-type distributed evacuation based on residents’ evacuation intentions in a hilly and mountainous area of Japan Open
Flooding and landslide disasters caused by typhoons and heavy rains occur annually in many parts of the world. It is advisable to evacuate to safe places in advance when there is an imminent risk of a disaster. Delayed evacuation is a chal…
View article: ESTIMATING FRAGILITY CURVES FOR ASSET DAMAGE IN BUSINESS SECTOR CAUSED BY A FLOOD DISASTER: A CASE OF THE HEAVY RAIN EVENT OF JULY 2018 IN JAPAN
ESTIMATING FRAGILITY CURVES FOR ASSET DAMAGE IN BUSINESS SECTOR CAUSED BY A FLOOD DISASTER: A CASE OF THE HEAVY RAIN EVENT OF JULY 2018 IN JAPAN Open
This paper proposes fragility curves for asset damage based on questionnaire replies from companies that were affected by floods after the heavy rain event of July 2018 in Japan. Fragility curves are a probabilistic method for analyzing st…
View article: STATISTICAL ANALYSIS OF SALES RECOVERY PROCESS IN INDUSTRIAL SECTOR AFTER A FLOOD DISASTER: A CASE OF THE HEAVY RAIN EVENT OF JULY 2018
STATISTICAL ANALYSIS OF SALES RECOVERY PROCESS IN INDUSTRIAL SECTOR AFTER A FLOOD DISASTER: A CASE OF THE HEAVY RAIN EVENT OF JULY 2018 Open
本論文では,平成30年7月豪雨により被害を受けた地域に立地する事業所へのアンケート調査を基に,水害からの売上回復過程を分析した.分析では,売上が元の水準に回復するまでの日数及び複数の中間水準に回復するまでの日数を生存分析の手法によりモデル化した.その結果,浸水深,各種ライフライン被害,資金調達に関する状況等が売上回復速度や程度に与える影響を定量的に明らかとした.各要因の影響は製造業と非製造業で異なる場合が多く,例えば水道の被害日数は製造業に対してより大きな影響を与えていた.…
View article: ESTIMATION OF FLOOR PRODUCTION FUNCTION FOR URBAN ECONOMIC MODELS CONSIDERING BUILDING HEIGHT
ESTIMATION OF FLOOR PRODUCTION FUNCTION FOR URBAN ECONOMIC MODELS CONSIDERING BUILDING HEIGHT Open
建築物の生産性は都市の密度や形状,住環境に大きく影響する.一部の土地利用モデルでは,都市政策の市街地密度への影響分析が可能だが,建築床の生産性の考察は不十分である.建築コストの実証研究では,文献により想定するモデルが異なり,建物階数が建設費に与える影響は必ずしも明確ではない.本研究では,土地利用モデルでの活用を念頭に,日本の建築着工統計の個票データに基づき,建物階数を考慮した床生産関数を推計した.その結果,床面積当たりの建設単価は高層ほど高いことが推計された.また,推計した…
View article: Effects of Dynamical Change in Water Level on Local Scouring around Bridge Piers Based on In-Situ Experiments
Effects of Dynamical Change in Water Level on Local Scouring around Bridge Piers Based on In-Situ Experiments Open
To evaluate the stability of bridge piers affected by the local scouring, the existing formulas for estimating the maximum local scour depth have been developed based on the results of experiments conducted under a constant water level. Ho…
View article: Explaining the effective reproduction number of COVID-19 through mobility and enterprise statistics: Evidence from the first wave in Japan
Explaining the effective reproduction number of COVID-19 through mobility and enterprise statistics: Evidence from the first wave in Japan Open
This study uses mobility statistics combined with business census data for the eight Japanese prefectures with the highest coronavirus disease-2019 (COVID-19) infection rates to study the effect of mobility reductions on the effective repr…
View article: PROPOSAL OF SLOPE FAILURE PROBABILITY EVALUATION FORMULA USING COVARIANCE STRUCTURE ANALYSIS OF SLOPE CHART AND COLLAPSE HISTORY
PROPOSAL OF SLOPE FAILURE PROBABILITY EVALUATION FORMULA USING COVARIANCE STRUCTURE ANALYSIS OF SLOPE CHART AND COLLAPSE HISTORY Open
我が国では,豪雨や地震による斜面災害が多く発生しているが,斜面災害は周辺家屋等への直接被害だけでなく,インフラの断絶,孤立地域の出現といった二次災害の誘因となっている.本研究では,平成16年新潟県中越地震,平成19年新潟県中越沖地震で被災した新潟県を対象として,県管理の斜面カルテに加え,地震動強度指標データ,降水量,地質図,土壌図,植生図等の空間情報データの収集を行い,地質学,統計学の両観点から斜面崩壊の特徴を掴んだ.複数の説明変数の共分散構造分析から得られた潜在変数を用い…
View article: AN EXPERIMENTAL STUDY ON THE LOCAL SCOURING AROUND A CYLINDRICAL PIER AFFECTED BY DYNAMICAL CHANGE IN WATER LEVEL
AN EXPERIMENTAL STUDY ON THE LOCAL SCOURING AROUND A CYLINDRICAL PIER AFFECTED BY DYNAMICAL CHANGE IN WATER LEVEL Open
従来より橋脚周りの局所洗掘による橋脚の安定性評価に必要となる最大局所洗掘深さの推定式は,一定の通水位条件下での実験結果に基づいており,実河川での水位履歴のような水位の上昇・下降を考慮する場合への適用性は定かではない.そこで本研究では,円形橋脚模型を対象に,通水位の変動を繰り返すことによる橋脚周りの局所洗掘の進行に与える影響の把握を目的とした通水実験を行った.
View article: Explaining the Effective Reproduction Number of COVID-19 through Mobility and Enterprise Statistics: Evidence from the First Wave in Japan
Explaining the Effective Reproduction Number of COVID-19 through Mobility and Enterprise Statistics: Evidence from the First Wave in Japan Open
This study uses mobility statistics combined with business census data for the eight Japanese prefectures with the highest COVID-19 infection rates to study the effect of mobility reductions on the effective reproduction number (i.e., the …
View article: A RESTORATION PREDICTION MODEL FOR THE DAMAGED ROAD EMBANKMENTS BY STATISTICAL ANALYSIS OF MULTIPLE EARTHQUAKE DISASTER RECORDS
A RESTORATION PREDICTION MODEL FOR THE DAMAGED ROAD EMBANKMENTS BY STATISTICAL ANALYSIS OF MULTIPLE EARTHQUAKE DISASTER RECORDS Open
道路盛土は長距離にわたる線状構造物であるため，ある区間内における一部の被害の復旧に時間を要し，交通機能が損なわれる事例が多数報告されている．被害の軽重に応じて，被災した盛土部の規制期間を予測することができれば，代替道路の選定スケジュール，旅行時間の予測，孤立地域への支援などの様々な事後対策に活用することができる．
View article: ESTIMATING FRAGILITY CURVES FOR ASSET DAMAGE IN BUSINESS SECTOR CAUSED BY A FLOOD DISASTER: A CASE OF THE HEAVY RAIN EVENT OF JULY 2018
ESTIMATING FRAGILITY CURVES FOR ASSET DAMAGE IN BUSINESS SECTOR CAUSED BY A FLOOD DISASTER: A CASE OF THE HEAVY RAIN EVENT OF JULY 2018 Open
本論文では，平成30年7月豪雨において浸水被害を受けた企業から得たアンケート回答結果を基に，資産被害に関するフラジリティ曲線を推計した．フラジリティ曲線は，地震動等の外力に対する構造物の損傷や企業の操業能力への影響の大きさを確率論的に分析するための手法であり，災害被害想定の基本モデルとなるが，水害時の資産被害率については推計事例が存在しない．本研究において推計したフラジリティ曲線の被害率や被害額の期待値は，確定的な評価手法である治水経済調査マニュアル（案）の同指標よりもやや…
View article: REGRESSION OF IMBALANCED RIVER DISCHARGE DATA USING RESAMPLING TECHNIQUE
REGRESSION OF IMBALANCED RIVER DISCHARGE DATA USING RESAMPLING TECHNIQUE Open
Risk evaluation of bridge collapse requires a regression model for river discharge that not only covers the situation during precipitation but also an ordinary situation without it. Although data-driven approaches using machine learning ha…