瀬谷 創 | ![]() |
セヤ ハジメ | |
大学院工学研究科 市民工学専攻 | |
准教授 | |
土木・建築工学関係 |
Transportation networks have a hierarchical structure, and the spatial scale of their impact on urban growth differs depending on the hierarchy. However, in empirical analyses of the impacts that transportation has on land use and prices, such hierarchy is often examined using dummy variables, and the network dependence and heterogeneity of impacts are often ignored. Thus, this study develops a spatial regression method that considers not only spatial dependence, but also network dependence within a hierarchical transportation network. This method was developed by extending the random effects eigenvector spatial filtering approach. Subsequently, it was applied to a pre-existing analysis that focused on the impacts that high-speed rail (HSR) had on residential land prices in Japan over the last 30 years. The results of the analysis suggested that HSR lines had hierarchical effects on residential land prices. The results also provide interesting insight into the ongoing problem of Japanese urban hierarchy; that is, the excessive concentration of population and industry in the Tokyo metropolitan area.
Frontiers Media SA, 2022年05月23日, Frontiers in Sustainable Cities, 4研究論文(学術雑誌)
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In the Computable Urban Economic (CUE) Model, one land-use transport interaction (LUTI) model, improving the accuracy of the Location Choice Model is important to evaluate the effects of introducing urban transportation policies. However, our previous study revealed that the substantiation of the indirect utility function by a linear expenditure system has not been verified and that location choice behaviors estimated using the logit model depends on the adjustment factor. Therefore, in this study, we first examined the logical meaning of the utility function by a linear expenditure system, and then focused on identifying major constituent factors of the adjustment factor and statistically verified the adjustment factor and urban amenities. As a result, we have identified the following facts: that the conventional indirect utility function may underestimate the effect of introducing urban transportation policies; that if effects are estimated using WLS after adding housing supply factors to the indirect utility function, the estimation accuracy will be improved; and that the major constituent factors of the adjustment factor are those expressing local characteristics of cities and wards.
ELSEVIER SCIENCE BV, 2019年04月, JOURNAL OF URBAN MANAGEMENT, 8 (1), 89 - 108, 英語[査読有り]
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Because of the decline of physical abilities of the elderly, their mobility is more vulnerable to topographical factors than younger population groups. However, topographical factors have been neglected in studies on travel behavior, and elderly people's heterogeneous responses to topographical factors remain unknown. To fill this research gap, this study focuses on a hilly neighborhood called Koyo Newtown in Hiroshima City, Japan, where a multi-period (two waves) and multi-day (two weeks) panel survey was conducted in 2010 and 2011. The survey consisted of a GPS survey and a paper-based travel diary survey. In addition, a travel mode choice model is developed based on a panel mixed logit model. Heterogeneities are captured by introducing random effects to parameters of topographical factors, which are measured in terms of altitude difference, intensity of up/down movement, maximum slope, and changing slope. Furthermore, effects of introducing personal mobility vehicles (PM) to mitigate negative impacts of topographical factors are also evaluated. As a result, it is found that the altitude difference and maximum slope factors have significant impacts on mode choice decisions. The effectiveness of PM to support the mobility of elderly residents is also confirmed.
EDITORIAL BOARD EJTIR, 2017年05月, European Journal of Transport and Infrastructure Research, 17 (3), 411 - 424, 英語[査読有り]
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This study develops a spatially varying coefficient model by extending the random effects eigenvector spatial filtering model. The developed model has the following properties: its spatially varying coefficients are defined by a linear combination of the eigenvectors describing the Moran coefficient; each of its coefficients can have a different degree of spatial smoothness; and it yields a variant of a Bayesian spatially varying coefficient model. Moreover, parameter estimation of the model can be executed with a relatively small computational burden. Results of a Monte Carlo simulation reveal that our model outperforms a conventional eigenvector spatial filtering (ESF) model and geographically weighted regression (GWR) models in terms of the accuracy of the coefficient estimates and computational time. We empirically apply our model to the hedonic land price analysis of flood hazards in Japan. (C) 2016 Elsevier B.V. All rights reserved.
ELSEVIER SCI LTD, 2017年02月, SPATIAL STATISTICS, 19, 英語[査読有り]
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This study investigates Japanese drivers' over-speeding violation behaviors on expressways captured by a GPS-enabled smart phone App, called Safety Supporter and designed by the authors, with functions of both second-by-second safety diagnosis and traffic warning information provision as well as advices about safer driving. The research purpose is to clarify the effects of the App on safety improvements based on data from a three-month field experiment in 2014, where a series of questionnaire surveys were conducted. For the research purpose, a zero-inflated negative binomial regression model is adopted to represent over-speeding violation behaviors. As a result, drivers' heterogeneous responses to the App functions are confirmed with a focus on the role of driving safety change stages and the results highlight the importance of individualized safety measures. (C) 2017 The Authors. Published by Elsevier B.V.
ELSEVIER SCIENCE BV, 2017年, WORLD CONFERENCE ON TRANSPORT RESEARCH - WCTR 2016, 25, 1820 - 1828, 英語[査読有り]
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This paper attempts to assess the value of urban views in a bay city (Yokohama), Japan. Firstly, three types of views, open view (goodness of visibility), green view (visibility of open space), and ocean view (visibility of ocean), were quantified employing the viewshed analysis implemented on the GIS with airborne LiDAR data and 0.5 m x 0.5 m high resolution aerial photos. Secondly, hedonic analyses were conducted to test the capitalization of value of those views into condominium prices using the spatial multilevel additive regression (SMAR) model, where possible non-linearity, multilevel structure of condominiums (unit building), and spatial dependence were considered. This study implies that "very nice" open view (in terms of the amount of visibility) and ocean view may have a positive premium, whereas "slightly nice" open and ocean views may not. Also, a "moderate amount" of green view may raise condominium prices, but "poor" and "too much" green view may reduce condominium prices. These results indicate that the effects of views are indeed non-linear, and therefore it may be misleading to interpret the results obtained by linear models as existing studies have done. (C) 2016 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2016年07月, LANDSCAPE AND URBAN PLANNING, 151, 89 - 102, 英語[査読有り]
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This study proposes an approach for ex-post identification of the geographical extent of an area benefiting from a transportation project, using functional data analysis methods. Our approach focuses on real estate (land) price data for the ex-post spatial evaluation. First, we prepare a panel of land prices observed before, during, and after the project in the areas that are potentially impacted. Second, using functional data analysis, movements of land prices in each observed site during the target period are approximated by continuous functions. Third, using the functional ordinary Kriging technique, the functions for land price movements in each micro district are spatially predicted. Lastly, by employing the functional clustering (functional K-means) technique, potential areas of benefit may be identified. Different from exiting before-and-after methods, including difference-in-differences method, the proposed procedure based on functional data analysis can describe a map with a complex spatial distribution pattern of benefit rather than using distance bands (ring buffer) from transportation cores, such as railway stations, bus stops, and highway interchanges. Then, the proposed procedure is empirically applied to a large-scale Japanese heavy railway project. The obtained result shows so-called redistributive effect, that is, land prices decrease around exiting stations and increase around new stations. In addition, interestingly enough, the spatial distribution pattern of the identified areas of benefit using this procedure are fairly similar to that of ex-ante predicted areas of benefit by the hedonic approach. Thus, capitalization is observationally confirmed with regard to accessibility improvement. (C) 2016 Elsevier Ltd. All rights reserved.
ELSEVIER SCI LTD, 2016年07月, JOURNAL OF TRANSPORT GEOGRAPHY, 55, 1 - 10, 英語[査読有り]
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An assessment of residential CO2 emissions is typically performed through the intensity method, in which total energy consumption is estimated by multiplying floor space by intensity value. Although spatially detailed intensity data is required for an accurate estimation, the finer spatial resolution will result in a less stable estimated value due to the small sample size; hence, existing studies in Japan created intensity data at a regional or prefectural level. The objective of this study is to create municipality level intensity data via a statistical approach, using the household level micro data from the National Survey of Family Income and Expenditure, of the Ministry of Internal Affairs and Communications, Japan, by focusing on electricity. First, this study builds several (spatial) statistical models, where per household electricity expenditure is regressed on housing types (two categories), household types (seven categories), and other household specific variables. Second, by substituting averaged municipality level explanatory variables from official statistics into the model, it estimates municipality level intensity data. The obtained results suggest that conventional intensity data in Japan, created by the simple average of samples in each unit (prefecture), may suffer from an upward bias, suggesting a danger of overestimation of residential CO2 emissions. (C) 2015 Elsevier Ltd. All rights reserved.
ELSEVIER SCI LTD, 2016年01月, APPLIED ENERGY, 162, 1336 - 1344, 英語[査読有り]
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Eigenvector-based spatial filtering is one of the often used approaches to model spatial autocorrelation among the observations or errors in a regression model. In this approach, a subset of eigenvectors extracted from a modified spatial weight matrix is added to the model as explanatory variables. The subset is typically specified via the selection procedure of the forward stepwise model, but it is disappointingly slow when the observations n take a large number. Hence, as a complement or alternative, the present article proposes the use of the least absolute shrinkage and selection operator (LASSO) to select the eigenvectors. The LASSO model selection procedure was applied to the well-known Boston housing data set and simulation data set, and its performance was compared with the stepwise procedure. The obtained results suggest that the LASSO procedure is fairly fast compared with the stepwise procedure, and can select eigenvectors effectively even if the data set is relatively large (n = 10(4)), to which the forward stepwise procedure is not easy to apply.
WILEY, 2015年07月, GEOGRAPHICAL ANALYSIS, 47 (3), 284 - 299, 英語[査読有り]
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Here, the authors propose the concept of a local electricity-sharing system as a complement or alternative to a feed-in tariff to achieve CO2-neutral transportation in cities. In the authors' proposed system, electricity generated from widely introduced solar photovoltaic panels (PVs) is stored in the cars 'not in use' in a city. In Japan, almost half of the cars in the central Tokyo metropolitan area are used only on weekends and thus are kept parked during weekdays. These cars represent a huge new potential storage depot if they were replaced by electric vehicles (EVs), that is, they could be used as storage batteries in a vehicle-to-grid system. Using an agent-based transportation simulator (MATSim), the authors modelled the effects of a large-scale introduction of EVs and PVs on the hourly regional power demand-supply for Yokohama city, Japan. The results of our simulation suggest that CO2-neutral EV trips can be achieved only during periods with current average solar irradiance.
Institution of Engineering and Technology, 2015年02月01日, IET Intelligent Transport Systems, 9 (1), 38 - 49, 英語[査読有り]
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Although city scale aggregate electricity demands are usually estimated by multiplying intensity data by floor space, in Japan there are few available sources for municipality level building stock (floor space) data. Hence in this study, we attempt to create municipality level building stock data using the techniques of spatial statistical downscaling. Firstly, this study compares predictive accuracy of several downscaling methods including both deterministic and statistical ones. The results support the use of statistical downscaling methods, which consider spatial autocorrelation or spatial heterogeneity. Secondly, it actually creates building stock data of Japan at municipality level (1803) in 2005 by downscaling prefectural level (49) data employing one of the spatial statistical downscaling methods. Thirdly, using the estimated building stock data, it empirically estimates electricity demand at municipality level. (C) 2015 The Authors. Published by Elsevier Ltd.
ELSEVIER SCIENCE BV, 2015年, CLEAN, EFFICIENT AND AFFORDABLE ENERGY FOR A SUSTAINABLE FUTURE, 75, 2751 - 2756, 英語[査読有り]
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This study investigated the moderation of the urban heat island via changes in the urban form in the Tokyo metropolitan area (TMA). Two urban scenarios with the same population as that of the current urban form were used for sensitivity experiments: the dispersed-city and compact-city scenarios. Numerical experiments using the two urban scenarios as well as an experiment using the current urban form were conducted using a regional climate model coupled with a single-layer urban canopy model. The averaged nighttime surface air temperature in TMA increased by similar to 0.34 degrees C in the dispersed-city scenario and decreased by similar to 0.1 degrees C in the compact-city scenario. Therefore, the compact-city scenario had significant potential for moderating the mean areal heat-island effect in the entire TMA. Alternatively, in the central part of the TMA, these two urban-form scenarios produced opposite effects on the surface air temperature; that is, severe thermal conditions worsened further in the compact-city scenario because of the denser population. This result suggests that the compact-city form is not always appropriate for moderation of the urban-heat-island effect. This scenario would need to combine with other mitigation strategies, such as the additional greening of urban areas, especially in the central area. This study suggests that it is important to design a plan to adapt to higher urban temperatures, which are likely to ensue from future global warming and the urban heat island, from several perspectives; that is, designs should take into account not only climatological aspects but also impacts on urban inhabitants.
AMER METEOROLOGICAL SOC, 2014年08月, JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY, 53 (8), 1886 - 1900, 英語[査読有り]
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Recently, model averaging techniques have been employed widely in empirical investigations as an alternative to the conventional model selection procedure, a procedure criticized because it disregards a major component of uncertainty, namely, uncertainty regarding the model itself, and, thus, it leads to the underestimation of uncertainty regarding the quantities of interest. Bayesian model averaging (BMA) is one of the most popular model averaging techniques. Some studies indicate that BMA has cumbersome aspects. One of the major practical issues of using BMA is its substantial computational burden, which obstructs the process of obtaining exact estimates. A simulation method, such as Markov chain Monte Carlo (MCMC), is required to resolve this problem. Weighted-average least squares (WALS) estimation has been proposed as an alternative to BMA. The computational burden of WALS estimation is negligible; therefore, it does not require the MCMC method. Furthermore, WALS estimation has theoretical advantages over BMA estimation. This article presents two contributions to the WALS literature. First, it applies WALS to spatial lag/error models in order to consider spatial dependence. Se
Wiley, 2014年04月, Geographical Analysis, 46 (2), 126 - 147, 英語[査読有り]
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企業間の業務交通が産業集積の一因であることは古くから指摘されている.そこで本研究では,パーソントリップ(PT)調査の業務交通トリップデータを用いて産業集積の度合いを計測することを試みる.具体的には,小ゾーン単位の東京都市圏PT調査の産業分類別打合せ・会議トリップに空間スキャン統計量(spatial scan statistics)を適用することで,東京23区における産業分類別の打合せ行動の空間的な集積やその変化を考察する.また,当該集積パターンと産業分類別従業員数の空間集積パターンを比較し,後者が前者を必ずしも拿捕し得るものではないことを指摘する.本研究の結果は,08年東京PT調査では対象外とされた業務交通トリップに関する調査が,face to faceのコミュニケーションの定量化のための有用な基礎資料と成り得ることを実証的に示すものである.
Japan Society of Civil Engineers, 2014年, 土木学会論文集D3(土木計画学), 70 (5), I_343 - I_351, 日本語Studies have suggested the importance of implementing climate change mitigation and adaptation measures in combination with considering possible co-benefit and trade-off among them. However, quantification of such cobenefit/ trade-off at city level is still in its infancy. Accordingly, using a micro zone level spatial explicit land use model which we have developed, this study assesses the co-benefit/trade-off of mitigation measure (compact city policy) and adaptation measure (retreat from high flood hazard areas) from the view point of CO2 emissions and expected loss due to the damage by river floods. For the assessment of residential CO2 emissions, this paper utilizes the microdata of National survey of family income and expenditure. The results suggest the importance of careful planning to create compact city to avoid trade-off. This study was funded by "Research Program on Climate Change Adaptation (RECCA)" of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.
Elsevier Ltd, 2014年, Energy Procedia, 61, 357 - 360, 英語[査読有り]
研究論文(国際会議プロシーディングス)
Spatially-fine data of gridded population of the world (GPW) is useful for various objective including energy demand modelling, climate modelling, urban mitigation/adaptation planning, among others. However, future projection of GPW is typically performed using fairly simple methods, and its validity is still unclear. This study first empirically compares the performances of several representative methods for GPW projection (forecasting), subsequently it performs scenario creations of Japanese residential electricity demand for 2050 using the population projections, derived using the models, multiplied by an intensity. This paper discusses the potential dangers of applying widely used constant-share method to the depopulation country like Japan, which include urban declining regions. (C) 2014 The Authors. Published by Elsevier Ltd.
ELSEVIER SCIENCE BV, 2014年, INTERNATIONAL CONFERENCE ON APPLIED ENERGY, ICAE2014, 61, 1446 - 1450, 英語[査読有り]
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In order to design energy resilient communities against disaster-driven blackout risks, this paper propose a new system to share photovoltaic (PV) generated green electricity using V2G technology, which we call vehicle to community (V2C) system. In this system, electricity generated from widely introduced solar photovoltaic panels (PVs) is stored in the "cars not in use" in a city. In Japan, almost half of the cars in the central Tokyo metropolitan area are used only on weekends and thus are kept parked during weekdays. These cars represent a huge new potential storage depot if they were replaced by electric vehicles (EVs), that is, they could be used as storage batteries in a V2G system to attain carbon neutral energy self-sufficient community. The results of our study showed that although the entire electricity surplus (PV supply minus demand) could be stored without waste if 12% of the EVs not in use were utilized as storage batteries at an aggregate (city) level in August (with maximum solar irradiance), there exist significant regional mismatches at the local district level. Hence, based on the geographical electricity surplus estimates, this paper develops a metaheuristic-based graph portioning spatial clustering algorithm to find optimal spatial clusters which minimizing local spatial discrepancies between electricity surplus and storage potential. (C) 2014 The Authors. Published by Elsevier Ltd.
ELSEVIER SCIENCE BV, 2014年, INTERNATIONAL CONFERENCE ON APPLIED ENERGY, ICAE2014, 61, 84 - 87, 英語[査読有り]
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After the Tohoku Earthquake, the concept of urban resilience has been discussed widely in Japan. Resilient cities cannot be realized without considering energy and natural disaster risks. In this paper several land-use scenarios are used for the Tokyo Metropolitan Area in 2050 using a land-use model considering these two aspects. These scenarios consider the co-benefits of [i] change of urban form (compact city), [ii] adaptation to flooding risks, and [iii] diffusion of electric vehicles (EVs) and solar photovoltaic (PV) panels. Also, in this paper the effects of emission factor change on direct/indirect CO2 emissions due to the shutdown of nuclear power plants after the earthquake are analyzed. The results suggest that the diffusion of PVs is more important in the non-nuclear world to reduce CO2 emissions, and that EVs still can contribute to CO2 emission reduction despite changes in emission factor. Also, compact urban form can effectively reduce CO2 emissions.
Eastern Asia Society for Transportation Studies, 2013年12月, Journal of the Eastern Asia Society for Transportation Studies (EASTS), Vol.10, 1025 - 1044, 英語[査読有り]
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The recent progress of spatial econometrics has developed a new technique called the "spatial hedonic approach," which considers the elements of spatial autocorrelation among property values and geographically distributed attributes. The practical difficulties in applying spatial econometric models include the specification of the spatial weight matrix (SWM), which affects the final analysis results. Some simulation studies suggest that information criteria such as AIC are useful for the SWM's selection, but if many model candidates exist (e.g., when the selections of explanatory variables are performed simultaneously), then the computational burden of calculating such criteria for each model is large. The present study develops an automatic model selection algorithm using the technique of reversible jump MCMC combined with simulated annealing termed trans-dimensional simulated annealing (TDSA). The performance of the TDSA algorithm is verified using the well-known Boston housing dataset, and it is applied empirically to a Japanese real estate dataset. The obtained results suggest a two-step strategy for model selection, with SWM (W) first, followed by the explanatory variables (X and WX), will result in local optima, and therefore these variables should be selected simultaneously. The TDSA algorithm can find the significant variables that are "hidden" because of multicollinearity in the unrestricted model, and can attain the minimum AIC automatically. © 2013 Elsevier B.V.
2013年05月, Regional Science and Urban Economics, 43 (3), 429 - 444, 英語[査読有り]
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This paper extends the concept of our proposed (Yamagata and Seya, 2012) community-based disaster resilient electricity sharing system (DRESS) as a complement or alternative to a feed-in tariff(FiT) to achieve CO2-neutral transportation in cities. In our proposed system, electricity generated from widely introduced solar photovoltaic panels (PVs) is stored in the"cars not in use "in a city. For example, almost half of the cars in the central Tokyo metropolitan area are used only on weekends and thus are kept parked during weekdays. These cars represent a huge new potential storage depot if they were replaced by electric vehicles (EVs), that is, they could be used as storage batteries in a V2G system. The present study extends our proposed system in the following two senses. Firstly, different from Yamagata and Seya (2012), this paper uses actual ground area data (footprint) of each building to estimate PV supply, which may lead to more accurate estimations. The results show that although the entire electricity surplus (PV supply minus demand) could be stored without waste if 12% of the EVs not in use were utilized as storage batteries at an aggregate (city) level,there exist significant regional mismatches at the local district level. Hence secondly, based on the geographical PV supply-demand estimates, this paper analyses the possibility of local electricity sharing by looking at the geographical distribution of high-storage potential areas using a spatial clustering technique. This paper extends the concept of our proposed (Yamagata and Seya, 2012) community-based disaster resilient electricity sharing system (DRESS) as a complement or alternative to a feed-in tariff(FiT) to achieve CO2-neutral transportation in cities. In our proposed system, electricity generated from widely introduced solar photovoltaic panels
Japan Management Training Center, 2013年, Innovation and Supply Chain Management, 7 (3), 75 - 82, 英語This paper extends our proposing (Yamagata and Seya 2012) concept of a community-based disaster resilient electricity sharing system (DRESS) as a complement or an alternative to the feed-in-tariff (FiT) to achieve CO 2 neutral in cities. In this system, electricity generated from widely introduced solar photovoltaic panels (PVs) is stored to the 'cars not in use' in a city. In the central part of the Tokyo metropolitan area, almost half of the cars is used only on weekends and are kept parking during the weekdays. Hence, there exists a huge new potential if those cars are replaced by electric vehicles (EVs) in the future, namely they may be used as new battery storages using vehicle to grid (V2G) at a community level. This study extends our previous paper. Firstly, by using actual ground areas of buildings, we estimate PVs supply potential more accurately. The result shows that the hourly electricity surplus (PV supply minus demand) can be fully stored without waste if 27% of the parking EVs are used as battery storage at the whole city level, although there exist significant spatial differences at local district level. Secondly, based on the geographical demand-supply estimates, we check the possibility of local electricity sharing by combing high and low storage potential districts to form electricity self-sufficient resilient communities. Finally, we analyze the optimal community clustering using Moran's I index. We show that the 40%, instead of 27%, is an optimal EV electricity sharing rate, if we consider the resilience against black-out risk. © 2013 IEEE.
2013年, Proceedings of the International Conference on Dependable Systems and Networks, 英語[査読有り]
研究論文(国際会議プロシーディングス)
Designing a future smart city (FSC) that copes with the reduction of CO2 has become one of the urgent tasks of the next 20years. One promising approach to achieve FSC is to combine appropriate land use (compact city with energy efficient buildings and photovoltaic panels (PVs)), transportation (electric vehicles (EVs) and public transportation system) and energy systems (smart grid systems), because of the interaction between these elements. However, there are few models which simulate these elements in an integrated manner. This paper presents the concept of the integrated model, and shows the land use-energy part of the model created for the Tokyo metropolitan area, which is the largest Mega city in the world. Firstly, a spatially explicit land use model (urban economic model) is constructed for the study area, and the model is calibrated using existing statistical data. Secondly, possible future compact/dispersion city scenarios for the year 2050 are created using the model. Thirdly, intra-day dynamics (hourly) of electricity demand and supply from PVs, which is assumed to be installed to the roofs of all detached houses in the study area, under two urban scenarios is simulated. The obtained results suggest that [1] "compact" urban form may contribute to the reduction of electricity demand from the residential sector, but [2] PV-supply under the scenario may also be reduced because of the decreased share of detached houses. Hence in the compact city scenario, it is important to discuss the effective use of vacant areas in suburbs, which may be used for large PV installations, or be re-vegetated to mitigate urban heat island effects. © 2013 Elsevier Ltd.
Elsevier Ltd, 2013年, Applied Energy, 112, 1466 - 1474, 英語[査読有り]
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本稿は,都市経済の実態や都市政策の実証評価を行うための分析ツールとして開発・実用化が進められてきた応用都市経済 (CUE)モデルのより一層の発展を目的として,現時点で残されている課題を整理した上で,今後の展望について議論するものである.はじめに,CUEモデルを取り巻く環境を概観しながらその特徴について述べる.次に,CUEモデルの課題について,理論面と実証面から網羅的に整理する.その上で,整理された課題に関して解決のための展望を述べるとともに,CUEモデルをさらに理論的に発展させる可能性についても議論する.
Japan Society of Civil Engineers, 2012年11月, 土木学会論文集D3(土木計画学), 68 (4), 344 - 357, 日本語[査読有り]
研究論文(学術雑誌)
With the collapse of the bubble economy in the early 1990s, economic disparities among both people and regions have arisen in Japan. Although developments in spatial econometrics have provided regional convergence studies with highly effective tools to explicitly consider spatial dependence and heterogeneity, there has as yet been no significant research on Japan's economic disparity using spatial econometrics. Moreover, most conventional regional convergence studies on Japan study the post-war high economic growth period before the economic bubble.Hence, the objective of this study is to analyze regional income disparities in Japan in the period after the bubble burst. We use the Bayesian spatial Durbin model, which can consider both spatial dependence and heterogeneity. The data used in this research are annual data collected at the municipality level during 1989-2007. To the best of our knowledge, no research has been conducted to analyze Japan's regional income disparities at the municipality level, though some research has been done at the prefecture level.First, the study suggests that σ-convergence does not hold whether or not spatial dependence is considered. Second, it analyzes regional income convergence by applying the simplified Bayesian spatial Durbin model to the β -convergence approach. The results show that β-convergence holds over 1990-2007. © 2010 Elsevier B.V.
2012年01月, Economic Modelling, 29 (1), 60 - 71, 英語[査読有り]
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研究論文(国際会議プロシーディングス)
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This study discusses the theoretical foundation of the application of spatial hedonic approaches-the hedonic approach employing spatial econometrics or/and spatial statistics-to benefits evaluation. The study highlights the limitations of the spatial econometrics approach since it uses a spatial weight matrix that is not employed by the spatial statistics approach. Further, the study presents empirical analyses by applying the Spatial Autoregressive Error Model (SAEM), which is based on the spatial econometrics approach, and the Spatial Process Model (SPM), which is based on the spatial statistics approach. SPMs are conducted based on both isotropy and anisotropy and applied to different mesh sizes. The empirical analysis reveals that the estimated benefits are quite different, especially between isotropic and anisotropic SPM and between isotropic SPM and SAEM the estimated benefits are similar for SAEM and anisotropic SPM. The study demonstrates that the mesh size does not affect the estimated amount of benefits. Finally, the study provides a confidence interval for the estimated benefits and raises an issue with regard to benefit evaluation. © 2009 Springer-Verlag.
2009年12月, Journal of Geographical Systems, 11 (4), 357 - 380, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(学術雑誌)
本研究課題では、リスク評価や防災に重点を置き、自然/人為による気候変動・変化に対する脆弱性を評価し、その脆弱性を軽減させる適応・緩和策の評価に注目する脆弱性アプローチ(ボトムアップアプローチ)によって、現在主流のトップダウンアプローチを補完する研究を提案する。低炭素化社会と気候変動へ適応した社会の実現のために、自治体の適応戦略の策定・検討に資する科学的知見を提供することを目的として、1. 過去から現在の土地利用変化情報を用いた地域気候モデルの現在気候再現実験結果及び過去の災害データを用いて、影響モデルによる風水害、農業被害の頻度や規模などについて脆弱性評価を実施し、社会システム、資源を脅かす要因を定量的に評価する(豪雨頻度・強度、低温・高温、有効降雨、人口変化など)。2. トップダウンアプローチによる将来の土地利用変化シナリオ、地域気候シナリオを用いて、気候変動・変化が風水害の脆弱性に及ぼす相対的な影響の大きさについて分析する。3. 風水害脆弱性評価に基づき、都市経済モデルによって適応シナリオを分析し、東京都担当者との意見交換を踏まえて、気候変動に対する適応戦略の検討を行う。4. 適応策を考慮した土地利用シナリオを地域気候モデルに組み込み、土地利用としての適応策が考慮されている地域気候シナリオが作成される。5. 適応策を考慮する場合としない場合について、気候変動、社会システムの変化に対する脆弱性評価を実施し、土地利用としての適応策の効果が考慮されている地域気候シナリオによる適応戦略を検討する。6. 適応戦略の検討結果を踏まえ、都市域と周辺地域での、低炭素化(コンパクトシティー等)、食料や水資源の確保、防災、生態系保全、高齢化などの多面的かつ現実的な視点も考慮した土地利用適応シナリオの検討を実施する。 本研究課題の現状、成果及び今後の展開について述べる。
水文・水資源学会, 2012年, 水文・水資源学会研究発表会要旨集, 25 (0), 260 - 260, 日本語学術書
学術書
学術書
本研究では,次世代交通システムの構成要素である「利用主体」「MaaS(Mobility as a Service)」「輸送主体」「CV(Connected Vehicle)による交通制御+道路インフラ」の特性を記述する数理モデルを構築し,これらの特性を数学的手法および数値計算によって解析し,さらに実データによって検証する.今年度(2020年度)は4年間の研究機関の初年度であり,各要素の条件を限定した比較的単純な数理モデルの構築と解析に着手した.今年度構築のモデルのポイントは,輸送主体やMaaSが多数のときの制度設計のための分析と,CVを前提とした優先制御の効果の分析の2点である.前者の分析においては,ネットワークに混雑が発生しない場合としうる場合の2つの状況を考慮した.混雑が発生しない場合は,輸送主体間に混雑による外部性が発生しないため,理想的状況では競争による最適な資源配分が期待できる.一方,混雑が発生する場合は,資源配分の調整が混雑により行われることになり,社会的損失が発生する.混雑料金や通行権のような規制により前者の状況を維持することが望ましい.それはできないときは,輸送主体間の外部性の排除を実現することが社会的に見てよりよい状況を実現するポイントとなる.後者の分析においては,輸送主体ごとに道路の容量を分割して割り振ることを制御の基本方策とした分析を行った.このための分析手法としては,信号機の適合制御で用いられる方法と,Cell Transmission ModelあるいはVariational Theoryを拡張した方法の2つを用いている.前者については大規模シミュレーションによる計算方法を開発している.後者については,いわゆるFirst in First Out制約の緩和による数理的手法を開発している.以上2点のほか,需要モデルの構築の着手も行っている.
令和3年度の研究実績として,主に以下に示す成果を得た. 1.差の差分(DD) 法による交通インフラ・ストック効果計測手法の開発と実証 我が国における高速道路整備がIC 周辺地域の雇用や事業所立地に及ぼす因果効果をランダムサンプリングと傾向スコアマッチング・差分の差分法を用いて推定した.その上で,処置群をいくつかの距離帯に分けて推定を行うことによって,効果の及ぶ空間範囲を明らかにした.さらに,従来より採用される代替的手法である,処置群の周辺地域(あるいは,周辺地域に含まれる個体)を対照群とする手法との比較を通じて,提案手法の有効性を示した.また,Synthetic control法や複数処置変数を考慮した傾向スコア法など新たな手法を適用し,交通インフラ整備の影響に関する実証分析を行なった. 2.操作変数法による高速交通ネットワーク整備政策の事後評価 三大都市(東京・大阪・名古屋)を除いた地方部の都市雇用圏を対象として,高速道路ネットワークの整備水準を示す市場アクセスと集積の経済を示す雇用者密度がそれぞれ地価に及ぼす因果効果の推定を行った.その際,欠落変数や逆の因果性によるバイアスが生じる可能性を考慮し,明治時代の市場アクセスと人口密度を操作変数とする操作変数法を採用した.推定の結果,市場アクセスと雇用者密度に関して共に有意な結果が得られたことから,高速道路ネットワークによる他都市へのアクセス性や雇用者密度が地価に正の因果効果を及ぼすことが明らかとなった.最小二乗法と操作変数法の推定値の差が比較的に小さいことから,これまでの高速道路整備が地方都市圏間で大きな偏りが生じないように満遍なく進められてきた可能性が示唆された.
本研究は,大規模小売店舗(大型店)の出店・撤退の影響を総合的な実証分析により把握することを目的としている.具体的には [I] 統計的因果推論アプローチ,[II] 構造推定アプローチ,[III] 行動モデルアプローチの3つのアプローチを用いて,研究期間内に以下の点を明らかにするものである.[I]大型店の出店・撤退が地域に与えた因果的な影響を統計的因果推論により明らかにする.[II] 経済モデルを用いて,[I]と合わせて複数のアプローチによる大型店の出店・撤退の影響分析を行うとともに,社会的厚生に与えた影響を明らかにする. [III]. 大型店の出店・撤退メカニズムを相互作用を考慮した行動モデルの開発と適用を通じて明らかにする.
昨年度は,[I],[II],[III] それぞれにおいて引き続き文献レビューとデータ収集を行うとともに,[I] については統計的因果推論手法の検証と関連する実証分析,[II],[III]については,アンケート調査に基づくモデル分析を行い,一定の成果を得た.具体的には,[I] については,「大型小売店データ」(東洋経済)と公示地価のデータセットを構築し,大規模小売店舗の出店が固定資産税に与える影響を考える上での基礎として,商業地価への影響を地方別に分析し,いくつかの有益な示唆を得た.また,その成果を論文として投稿した.[II],[III]については,アンケート分析に基づき,地域通貨両面市場における消費者と店舗の相互作用に関するモデル開発と実証分析を行った.
本申請課題では,今後も頻発することが見込まれる相乗型豪雨災害時の交通マネジメントのための理論再構築と社会への実装を行うことを目的とする。研究対象を被災直後から復興期までの4つの段階に分け,行動論の立場から主としてデータ収集,心理・行動分析,政策評価を行う。開発した一連の手法をパッケージ化したソフトウェア「TMRescue」(仮称)を,独自に収集した実データに適用し,実用性を検証する。 2021年度は、理論研究に基づきTMRescueの社会実装研究に取り掛かった。具体的には、 ①タイムライン型避難支援アーカイブの構築に関しては,タイムラインの考え方を援用し,土砂洪水氾濫被害に対応した避難支援アーカイブを構築した。被災者の意識や行動に関する自由回答形式のアンケート調査とSNSのテキストデータを取得し,機械学習手法の一つであるトピックモデルを適用して,住民避難の阻害要因を特定した。 ②災害時の動的交通情報提供システムの構築に関しては,災害発生後の公共交通運行の動的な交通情報提供システムを構築した。被災地区において居住地と避難所を結ぶグリーンスローモビリティによる移動支援の実験を行い,交通規制時の情報配信プラットホームを試行した。 ③時間・空間的集積を考慮した交通マネジメント施策の決定に関しては,災害時に関係者が自由にアクセスできるオープンデータとして,需給マッチング技術および需給均衡点の予測技術に公共交通情報提供技術を同期させ,被災後のTDM×TSMを実現するサービスコンテンツを試作した。 ④交通ネットワークの復旧優先度決定支援システムを用いた施策の評価に関しては,復旧優先度決定支援システムを相乗型豪雨災害の復旧・復興過程に適用し,道路区間の抽出,優先順位,交通容量の回復水準の妥当性について検証した。また,短時間で敷設可能な緊急仮橋モバイルブリッジの敷設効果を定量化した。
空間計量経済学の最重要課題を解決するとともにさらなる発展を目的として,[Ⅰ]空間重み行列の内生化に関する実証研究と新たなモデル開発 [Ⅱ]ビッグデータへの新たな対処法の開発 [Ⅲ]組成データ解析を応用した空間計量経済学の新たな展開 [Ⅳ]研究成果の公開・利用促進と日本における空間計量経済学分野の研究者の育成 の四つの課題に対し,それぞれ以下のとおり研究を実施した. [I] 空間重み行列Wの内生性を扱う方法論を整理した.また,昨年度に引き続き従来の空間計量経済モデルを計量経済学的に拡張することで実証研究への適用性を広げるため,いくつかのモデルにおいて新たに空間的自己相関を考慮することを試みた. [II] 100万オーダーの大規模な不動産データを用いて,深層学習,XGBoost等に代表される機械学習モデルと空間統計モデルの予測性能の比較を試みるとともに,新たな空間予測モデルの開発を行った.また計算効率を維持しながら,空間効果とその非空間効果を安定的に識別する方法,ならびに幅広い非ガウスデータをモデル化する方法を開発した. [III] 昨年度に引き続き,地理的加重回帰モデル(Geographically Weighted Regression: GWR)などに代表される「空間異質性」を考慮するモデルを,組成データに適用可能となるように拡張し,モデルの改良を行った. [IV] 本申請課題のメンバーが中心となって誘致した,空間計量経済学に関する国際組織であるSpatial Econometrics Association (SEA)の2021年度大会の全日程を確定させ, 5月26日-28日で開催するための準備を概ね完了した.前年10月に主催した国際ワークショップに参加した研究者からも多くの参加の見通しを得た.
現在,わが国の公共事業関係費は対GDP比で3.2%であり,ピーク時と比較して半減している.他方,欧米諸国との比較では,依然高い水準にある.この水準が適切であるかどうかの判断は,単純な各国比較や時系列比較だけでなく,理論的・実証的・構造的アプローチが不可欠である.理論的分析では動学マクロ経済学のフレームでインフラストラクチャーの特性を再定義し,理論的な最適性がどのような要因に依存するのかを検証する.その結果,不確実性が高いわが国では,インフラストラクチャーの社会的価値が高く,より高い水準での整備が正当化されることを証明した.実証的分析では社会資本ストック額および公共事業関係費と経済成長力に関する因果推論を実施することで,様々な面でのインフラストラクチャーの効果の計測に成功している.さらに,構造的分析では,建設産業および入札制度,地理的要因などに着目し,わが国の公共事業の費用構造に関する特異性を分析した.これら,3つの分析を総合的に判断し,最終的にはわが国の公共事業関係費の現状水準は,最適水準と比較して低いことがあきらかになった.そして,その要因をインフラの意思決定手法にあると考え,公共財としてではないインフラストラクチャーの価値としてまとめた.そこでは,これまでインフラストラクチャーがサミュエルソンが定義した公共財としての価値のみに注目していることを指摘し,宇沢弘文が定義した社会的共通資本としての価値,すなわち,国民の基本的権利を満たすものとする価値が存在し,その価値観の共有こそが重要であることを示した.次年度は,これらの知見を欧米のインフラストラクチャー評価手法と比較検討することで,わが国におけるインフラストラクチャーの評価手法の再構築を目指す.
本研究では、グローバルな視点からアジア途上国の国境まちづくりの実態を明らかにし、多様なコネクティビティを有する国境まちのあるべき姿を提示し、それを実現するための方法論を開発する。研究成果として、(1)貴重な一次データの収集;(2)国境まちへの定住に影響する要因の解明;(3)国境まちへの愛着形成、アイデンティティの保護・創出に関するエビデンスづくり;(4)国境まちの実態に合ったまちづくり戦略の提案;(5)PASSアプローチに基づくパンデミック政策の立案方法の提案;(6)COVID-19感染拡大の防止と観光経済活動の維持を両立するパッケージ政策の科学的なエビデンスに基づく提言を行うことができた。
本研究は,貿易統計の高度活用としてData Fusionに基づく貿易統計から真の貿易量を効率的に作成する方法を確立するため,貿易統計の不整合問題発生機構の解明に資する不整合要因診断システムを構築した.さらに,各国が整備する貿易統計のData Fusion技術として,教師なし機械学習である非負値行列因子分解法を不整合問題に適用した.エネルギー・環境・資源リスクに影響を与える水俣条約に着目し,水俣条約の規制対象である水銀・水銀含有製品に関する貿易統計の不整合問題を活用することで,水俣条約の実効性を評価した.
本研究では,交通環境だけでなく生活関連施設の配置等にまで影響を及ぼす可能性のある次世代モビリティ(自動運転・車両共同利用)導入の影響をシミュレートする土地利用・交通モデルを構築し,技術普及シナリオに内在する不確実性の定量分析を試みた.その結果,(1)自動運転の導入は,交通システムに対する直接的な影響だけでなく,施設の立地や居住地パターンに影響を及ぼす可能性が高いこと,(2)自動運転サービスの普及や導入の影響は自動運転車両の設計やマーケティングに依存し,その予測には極めて高い不確実性が内在していることが示唆された.
教科書な空間計量経済モデルは,データ欠損がなく,属性にエラーがなく,観測位置が正確という"clean"な空間データを仮定しており,"dirty"なデータには,そのまま適用することが難しい.本研究では,dirtyな空間データに対する統計分析手法の開発を試みた.具体的には,(1) 非ランダム欠損への対処法であるHeckmanのサンプルセレクションモデル,(2) 外れ値に頑健な(無条件)分位点回帰モデル,をそれぞれ援用して,空間データの持つ空間的自己相関という性質と不完全性の両者を考慮したモデルの構築とパラメータ推定方法の提案を行った.
競争的資金
本研究では、「若者が働き、住みたがる地方」への再生政策に関して、研究代表者が提唱している市民生活行動学をコアにそれを地方文化と公共政策と融合させた各種学融合研究方法論を多数開発した。そして、それらを応用し、多様な生活のことを考慮に入れた若者の移住・定住意思決定メカニズムの解明、地方独自の文化に立脚した魅力的な地方イメージづくり方法論と地域資源を活用した地域問題の解決につながる雇用機会の創出を図り、若者の行動変容ステージに応じた地方都市への移住・定住促進策の立案に寄与する研究成果を多数あげることができた。
交通量や交易量に代表される地域間のOrigin -Destination (OD) Flow Data を対象として、地理的な空間データの特質である空間的自己相関を明示的に考慮した計量分析と空間詳細化の方法を検討した。工場移転や人口移動などに関わる様々な実際のデータを用いた計量分析や空間集積の検出手法の開発を行った。また、統計学的アプローチに基づき、OD Flow Data の新たな空間詳細化の手法を提示した。
本研究では、欧米諸国等の先進国都市からアジアの途上国都市まで都市の発展段階が異なる多様なニュータウンを対象に、持続可能な居住地区のための新しい計画概念「自己完結性」を提案する。この概念は、活動がどの程度ニュータウン内で完結するかを計量化する指標である。住区の物理的条件に加えて、社会関係資本や社会的ネットワークといった社会的条件と交通行動の非市場的相互作用を記述する均衡モデルを構築した。この概念に基づき、途上国都市で将来出現するオールド・ニュータウン問題を緩和するための地区交通政策を提示した。最後に、先進国都市と途上国都市の間の順方向・逆方向の政策伝搬を明らかにするための分析手法を提示した。
実施者らの既往研究では,データの空間相関を考慮した欠損データの補完方法を提案した.しかし,そこでは,被説明変数yの空間相関のみが考慮され,説明変数Xの欠損復元においては,変数間の相関情報のみが利用されていた.そこで本課題では,Xの復元においても,空間情報を利用する形のモデル開発を行った.その結果次の2点が明らかになった.[1]空間情報を用いることで,正の空間相関の強い連続変数(例えば,賃料,アクセシビリティ)については,補完正確度を大きく向させられる可能性がある.[2]局所的な変動が大きい変数,例えば床面積や築年数については,空間情報の導入が逆にRMSEやバイアスの悪化を引き起こす場合が多い.
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