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- Haruhide Matsuda, Hajime Matsumura
- Graphs and Combinatorics
- 2006

- Haruhide Matsuda, Hajime Matsumura
- Discrete Mathematics
- 2005

- H Nishioka, H Ito, T Miki, T Hashimoto, H Nojima, H Matsumura
- Neuroradiology
- 1999

We report a Rathke's cleft cyst which presented as pituitary apoplexy, a rare presentation. A 46-year-old woman suffered sudden headache and visual loss. T1-weighted MRI 3 weeks after this apoplectic episode demonstrated a cystic lesion between the anterior and posterior lobes of the pituitary, with some high-signal material layering in it. The mass showed… (More)

- Jun Fujisawa, Hajime Matsumura, Tomoki Yamashita
- Graphs and Combinatorics
- 2010

In this paper, we give a sufficient condition for a graph to have a degree bounded spanning tree. Let n ≥ 1, k ≥ 3, c ≥ 0 and G be an n-connected graph. Suppose that for every independent set S ⊆ V(G) of cardinality n(k − 1) + c + 2, there exists a vertex set X ⊆ S of cardinality k such that the degree sum of vertices in X is at least |V(G)| − c − 1. Then G… (More)

We propose a method for improving motivation to participate in sensing services by presenting rankings in multidimensional hierarchical sets. We call this method <i>Top of Worlds</i>. Because previously proposed methods only rank a user among all other users, many have little chance of being ranked in the top group, resulting in little motivation to… (More)

- Hajime Matsumura
- Discrete Mathematics
- 2005

Dirac and Ore-type degree conditions are given for a bipartite graph to contain vertex disjoint cycles each of which contains a previously specified edge. This solves a conjecture of Wang in [6]. In this paper, we only consider finite undirected graphs without loops and multiple edges. For a vertex x of a graph G, the neighborhood of x in G is denoted by… (More)

- Yutaka Arakawa, Takayuki Nakamura, Motonori Nakamura, Hajime Matsumura
- 2013 IEEE 37th Annual Computer Software and…
- 2013

We propose an indexing method called UBI-Tree for improving the efficiency of a new type of data search called schema-less search. Schema-less search is a multi-dimensional range search from a wide variety of data, such as sensor data, collected through participatory sensing. Such data have different types and number of dimensions because a participant uses… (More)

- Hajime Matsumura
- 1996

Hofstadter's diagram, or the energy spectrum against the magnetic field in tight-binding systems, is obtained for the models having flat (dispersionless) one-electron band(s) that have originally been proposed for itinerant spin ferromagnetism. Magnetic fields preserve those flat bands that arise from a topological reason, while dispersions emerge in a… (More)

- Ryota Matsubara, Hajime Matsumura, Masao Tsugaki, Tomoki Yamashita
- Discrete Mathematics
- 2017

- Hajime Matsumura
- Discussiones Mathematicae Graph Theory
- 2015

A k-tree is a tree with maximum degree at most k. In this paper, we give a degree sum condition for a graph to have a spanning k-tree in which specified vertices have degree less than k. We denote by σ k (G) the minimum value of the degree sum of k independent vertices in a graph G. Let k ≥ 3 and s ≥ 0 be integers, and suppose G is a connected graph and σ k… (More)