近年，ビッグデータの新たな分析手法として，クラスタリング手法の1つであるグラフ研磨が提案されている．グラフ研磨はグラフに属する頂点を類似指標に基づいてグルーピングする方法である．本研究では，グラフ研磨を用いて交通系ICカードの乗降履歴データに基づくOD表から乗降パターンが類似する駅を抽出する．具体的には，香川県で運行されている鉄道路線「ことでん」において利用可能な交通系ICカード「IruCa」の2013年12月1日から2015年2月28日までの15カ月間に得られた乗降履歴データを用いる．この期間に蓄積されたデータは9,008,709件であり，得られるOD表にグラフ研磨を適用した．得られた結果からは，利用件数の大小に関わらず類似した乗降パターンを持つ駅を抽出できることが明らかとなった．このような本研究の成果により，交通需要分析におけるグラフ研磨の有用性が確認された．

 1. Introduction

 In Japan, as the number of children is decreasing and the number of elderly people is increasing, compact town development is required in mountainous areas. Nichinan Town is part of the Tottori Prefecture and is located in a primarily mountainous region. The shifting of residents to urban areas as well as the declining birth rate and aging populace has led to a decline in the population of this town. It now aims to become a "compact village", with centralized public utility facilities, centrally located elementary and junior high schools, and less wasteful living and administration systems.

 2. Purpose

 Nichinan Town has been promoting "Central Area Development Project" for over 20 years. Its current population is 4,000, and this continues to decline. Furthermore, the number of elementary and junior high school students is less than 10% of that in 1970. Ever since a municipality merger in 1959, this town has been promoting the compact village by integrating junior high schools in 1974, nursery schools in 2006, and elementary schools in 2009, and then consolidating them into the Kasumi district. This study clarifies the history and current situation for consolidating public utility facilities for the Shoyama/Kasumi districts in central area.

 3. Conclusion

 1) Nichinan Town has undergone a rapid population decline, with a declining birthrate and an aging population that has shrunk to 30% of its postwar peak. The public utility facilities have also been consolidated owing to the history of industrial decline, such as that of the Tatara iron and chrome mines, as well as the severe climate and geographical conditions in the region.

 2) Nichinan junior high schools were integrated in the 1970s, although elementary schools continued to exist in each old village for 80 years, from the Taisho period to 2009. Collective discussions proposing the integration of elementary schools greatly contributed toward the formulation of "Central Area Development Project" in 2010.

 3) Even in the small-scale municipality of this town, large-scale consolidation involving the relocation of public utility facilities required a long period of half a century. Consolidation into the Kasumi district, which is adjacent to the Shoyama district of the old town center, was an important condition for obtaining consensus among the townspeople.

 4) The future plans for the town include settling and industrial promotion measures that have been formulated in recent years. These plans not only focus on concentrating the facilities in the Kasumi district but also intend to promote agriculture and forestry using forest resources and human resource development. Further, they include efforts to connect the central area to the old villages.

公共交通の活性化および再生のためには，利用実態に応じた運行計画の見直しが必要である．そこで，公共交通の利用実態の把握が重要となる．本研究では公共交通の利用実態とその長期変動を把握することを目的とする．分析に際して，鉄道路線「ことでん」を対象において，分析期間は2016年4月1日から2019年9月30日までと設定し，この期間に収集された交通系ICカードデータを用いる．本研究ではことでんの利用実態の時間的特徴と空間的特徴を同時に抽出し，得られる分析結果の解釈性を上げるために，正則化非負値テンソル因子分解と区分線形近似モデルを用いた方法論を提案する．提案手法を交通系ICカードデータに適用することで，「どの駅から，どの駅へ，いつ」利用があったのかという利用パターンを抽出し，ことでんの利用実態を把握した．そして，その利用実態がどのように変動したのかを明らかにした．