The University of Tokyo · Social Sciences
Professor Hiroyuki Usui's research lab specializes in urban spatial analysis and computational urbanism, focusing on the geometric and regulatory dimensions of urban form. The lab investigates the statistical distributions of urban elements such as building lot dimensions, building heights, and vacant lot patterns, often integrating spatial statistics, zoning regulations, and computational geometry. Key research directions include modeling neighborhood relationships using Voronoi-based diagrams, analyzing the impact of zoning policies on urban morphology, and examining the spatial patterns of urban vacancy and perforation. The lab combines theoretical modeling with empirical data to address urban planning challenges in complex, irregular urban environments.
Figures are computed from collected data and may differ slightly.
Modern SoCs integrate multiple CPU cores and hardware accelerators (HWAs) that share the same main memory system, causing interference among memory requests from different agents. The result of this interference, if it is not controlled well, is missed deadlines for HWAs and low CPU performance. Few previous works have tackled this problem. State-of-the-art mechanisms designed for CPU-GPU systems strive to meet a target frame rate for GPUs by prioritizing the GPU close to the time when it has to
The neurogenic responses of cerebral arteries of humans and the monkey were compared with those of the dog. alpha-Adrenoceptors in these cerebral arteries were also characterized by radioligand-binding studies. In human posterior communicating arteries, the contractile response to electrical transmural stimulation was attenuated by treatment with phentolamine in 41% of preparations tested, but not affected by aspirin. The responses in the monkey and canine arteries were not attenuated by treatme
A building lot represents one of the most important basic spatial objects of urban form because building lots are basically adjacent to road networks and combine to make an exact whole with no leftover space. Thus, it is important to understand the relationship between the sizes and shapes of building lots and the density of buildings and road networks at a district scale. While building lot sizes and frontages are known to follow a log-normal distribution, respectively, the probability density
Building height is one of the most important determinants of streetscapes. According to zoning regulations in countries such as Japan, building heights are indirectly controlled by the floor area ratio (FAR). The maximum FAR and the building coverage ratio (BCR) represent the main tools of zoning regulations, which legally regulate building shapes and volumes based on plot sizes at the district scale. If plot sizes and shapes are uniform due to zoning regulations, uniform building shapes (both t
The aim of this article is to describe a convenient but robust method for defining neighbourhood relations among buildings based on ordinary Delaunay diagrams (ODDs) and area Delaunay diagrams (ADDs). ODDs and ADDs are defined as a set of edges connecting the generators of adjacent ordinary Voronoi cells (points representing centroids of building polygons) and a set of edges connecting two centroids of building polygons, which are the generators of adjacent area Voronoi cells, respectively. Alth
According to the Japanese government, vacant lots are randomly generated and accumulated (without being rebuilt after demolition) in the process of increasing vacant lots, a phenomenon called urban perforation. Urban perforation in urban areas may trigger a high degree of inefficiency in public infrastructure management. However, this observation lacks theoretical and empirical foundations, a lacuna to which this paper will focus on. Consequently, our research objectives are to confirm: (1) whet
The concept of density lacks the ability to explain the diversity of physical elements of urban form such as building lot sizes. Thus, urban planners tend to discuss the validity of density values without taking into consideration the variation of building lot sizes due to the limited data available on building lot shapes. Our objective is to discuss the potential of building density and road network density in order to estimate the size distribution of building lots at the district scale in dow
Measuring building setbacks and heights along streets is important for evaluating the variability of streetscape skeletons, the 3D spaces of streets defined by the arrangement of surrounding buildings. Its evaluation requires computing the streetscape width, defined as the front road width of a building plus the setbacks of both sides of the front roads, the building heights and the ratio of the streetscape width to the building height, known as the streetscape width-to-height ratio. However, me
The size distribution of urban blocks is important for the characterisation of urban block patterns and is known to follow several parametric statistical distributions. However, it has not previously been analysed on the basis of a normative plane tessellation and in terms of urban block density and mean road width. In this article, we formulate the size distribution of Voronoi cells using the gamma distribution estimated by urban block density and mean road width. We found that (1) both log-nor
Precise building height is indispensable for evaluating variability in building heights. However, relevant data are not always available. Conventionally, building height is approximated as the product of the number of building storeys and floor height, called approximated building height. However, there is no consensus on how floor height, a key determinant of approximated building height, should be set. In Japan, increasingly precise building height data are becoming available as an open 3D urb
敷地奥行の平均は地域における典型敷地を特定するための重要な指標の一つである．ところが，敷地奥行のデータを直接入手することは容易でない．本稿では，敷地間口に対する敷地面積の比を敷地奥行と定義する．もし，敷地間口と敷地奥行の同時分布が互いに独立であるならば，敷地奥行の平均は敷地間口の平均に対する敷地面積の平均の比と等しくなる．そこで，敷地奥行の平均を敷地間口の平均に対する敷地面積の平均の比から推定することを考える．仮説：敷地間口と敷地奥行の同時分布は互いに独立かどうかを統計的に検定するため，ノンパラメトリック検定を行った．その結果，1)有意水準5%において，仮説は必ずしも採択されるとは限らないこと，2)地域における道路網パターンが格子状の場合，平均敷地奥行と敷地間口の平均に対する敷地面積の平均の比の相対誤差は4%であるのに対して，地域における道路網パターンが不規則の場合，当該相対誤差は21%であることがわかった．したがって，平均敷地奥行の推定精度は，地域における道路網パターンの違いや建物配置の違いに依存するといえる．
We propose the following method for evaluating road network patterns. An evaluation of these patterns is important not only for an understanding of the structure of a city, but also for compliance with the rule in the Building Standards Law (the basic law related to buildings and cities in Japan), that makes it possible to preserve lanes (i.e., narrow roads less than four meters wide). This rule, however, does not provide a method for judging whether or not road network patterns are laid out in
Modern SoCs integrate multiple CPU cores and Hardware Accelerators (HWAs) that share the same main memory system, causing interference among memory requests from different agents. The result of this interference, if not controlled well, is missed deadlines for HWAs and low CPU performance. State-of-the-art mechanisms designed for CPU-GPU systems strive to meet a target frame rate for GPUs by prioritizing the GPU close to the time when it has to complete a frame. We observe two major problems whe
Open papers in the app to read, cite, and organize with AI.
