Multi-channel Sampling on Graphs and Its Relationship to Graph Filter Banks

In this paper, we consider multi-channel sampling (MCS) for graph signals. We generally encounter full-band graph signals beyond the bandlimited one in many applications, such as piecewise constant/smooth and union of bandlimited graph signals. Full-band graph signals can be represented by a mixture of multiple signals conforming to different generation models. This requires the analysis of graph signals via multiple sampling systems, i.e., MCS, while existing approaches only consider single-channel sampling. We develop a MCS framework based on generalized sampling. We also present a sampling set selection (SSS) method for the proposed MCS so that the graph signal is best recovered. Furthermore, we reveal that existing graph filter banks can be viewed as a special case of the proposed MCS. In signal recovery experiments, the proposed method exhibits the effectiveness of recovery for full-band graph signals

Dynamic Sensor Placement Based on Graph Sampling Theory

In this paper, we consider a dynamic sensor placement problem where sensors can move within a network over time. Sensor placement problem aims to select M sensor positions from N candidates where M < N. Most existing methods assume that sensors are static, i.e., they do not move, however, many mobile sensors like drones, robots, and vehicles can change their positions over time. Moreover, underlying measurement conditions could also be changed that are difficult to cover the statically placed sensors. We tackle the problem by allowing the sensors to change their positions in their neighbors on the network. Based on a perspective of dictionary learning, we sequentially learn the dictionary from a pool of observed signals on the network based on graph sampling theory. Using the learned dictionary, we dynamically determine the sensor positions such that the non-observed signals on the network can be best recovered from the observations. Furthermore, sensor positions in each time slot can be optimized in a decentralized manner to reduce the calculation cost. In experiments, we validate the effectiveness of the proposed method via the mean squared error (MSE) of the reconstructed signals. The proposed dynamic sensor placement outperforms the existing static ones both in synthetic and real data

Graph Signal Sampling Under Stochastic Priors

We propose a generalized sampling framework for stochastic graph signals. Stochastic graph signals are characterized by graph wide sense stationarity (GWSS) which is an extension of wide sense stationarity (WSS) for standard time-domain signals. In this paper, graph signals are assumed to satisfy the GWSS conditions and we study their sampling as well as recovery procedures. In generalized sampling, a correction filter is inserted between sampling and reconstruction operators to compensate for non-ideal measurements. We propose a design method for the correction filters to reduce the mean-squared error (MSE) between original and reconstructed graph signals. We derive the correction filters for two cases: The reconstruction filter is arbitrarily chosen or predefined. The proposed framework allows for arbitrary sampling methods, i.e., sampling in the vertex or graph frequency domain. We also show that the graph spectral response of the resulting correction filter parallels that for generalized sampling for WSS signals if sampling is performed in the graph frequency domain. Furthermore, we reveal the theoretical connection between the proposed and existing correction filters. The effectiveness of our approach is validated via experiments by comparing its MSE with existing approaches

Measuring the quality of life of long-term care service users in Japan: a cross-sectional questionnaire study

[Background] In Japan’s super-aging society, the number of long-term care service providers is increasing, and the quality of care is a matter of concern. One aspect of the quality of care is the user’s quality of life. The questionnaires EQ-5D and WHO-5 are representative indicators of quality of life. Herein, we aimed to measure the quality of life in long-term care service users in Japan and to clarify the relationship between quality of life and the level of care required. [Methods] A questionnaire study was conducted in 106 facilities of 22 corporations. In addition to the EQ-5D and WHO-5, sex, age, and the level of care required were assessed by descriptive statistics. Bonferroni’s multiple comparison test was used to analyze each quality of life score, and the differences by sex and age were analyzed multiple regression analyses, with each quality of life score as the objective variable. [Results] Of 4647 cases collected, 2830 were analyzed, with no missing data. Both indicators tended to be lower than the general older population. Those scores tended to be higher in females than males (EQ-5D: males, 0.58 ± 0.26; females, 0.60 ± 0.24; P = 0.06 and WHO-5: males, 13.8 ± 5.92; females 14.9 ± 5.70; P < 0.001). In terms of age, those under 65 years old with specific diseases had lower EQ-5D scores than those in other age groups (P < 0.001); however, WHO-5 scores did not differ by age. Multiple regression analysis showed a significant association between the EQ-5D score and level of care required, except for support-required level 1, which tended to worsen as the level of care required increased. Conversely, the WHO-5 score was significantly lower for care need levels 2, 4, and 5. [Conclusions] The quality of life of long-term care service users was worse than that of the general older population, it tended to be low among males and those under 65 years old with specific diseases. Furthermore, it gradually decreased as the level of care required increased. It is important to monitor users’ quality of life as a quality indicator of care, to improve and manage it

Vaccinium myrtillus (Bilberry) Extracts Reduce Angiogenesis In Vitro and In Vivo

Vaccinium myrtillus (Bilberry) extracts (VME) were tested for effects on angiogenesis in vitro and in vivo. VME (0.3–30 µg ml−1) and GM6001 (0.1–100 µM; a matrix metalloproteinase inhibitor) concentration-dependently inhibited both tube formation and migration of human umbilical vein endothelial cells (HUVECs) induced by vascular endothelial growth factor-A (VEGF-A). In addition, VME inhibited VEGF-A-induced proliferation of HUVECs. VME inhibited VEGF-A-induced phosphorylations of extracellular signal-regulated kinase 1/2 (ERK 1/2) and serine/threonine protein kinase family protein kinase B (Akt), but not that of phospholipase Cγ (PLCγ). In an in vivo assay, intravitreal administration of VME inhibited the formation of neovascular tufts during oxygen-induced retinopathy in mice. Thus, VME inhibited angiogenesis both in vitro and in vivo, presumably by inhibiting the phosphorylations of ERK 1/2 and Akt. These findings indicate that VME may be effective against retinal diseases involving angiogenesis, providing it can reach the retina after its administration. Further investigations will be needed to clarify the major angiogenesis-modulating constituent(s) of VME

Lossy Compression of Adjacency Matrices by Graph Filter Banks

This paper proposes a compression framework for adjacency matrices of weighted graphs based on graph filter banks. Adjacency matrices are widely used mathematical representations of graphs and are used in various applications in signal processing, machine learning, and data mining. In many problems of interest, these adjacency matrices can be large, so efficient compression methods are crucial. In this paper, we propose a lossy compression of weighted adjacency matrices, where the binary adjacency information is encoded losslessly (so the topological information of the graph is preserved) while the edge weights are compressed lossily. For the edge weight compression, the target graph is converted into a line graph, whose nodes correspond to the edges of the original graph, and where the original edge weights are regarded as a graph signal on the line graph. We then transform the edge weights on the line graph with a graph filter bank for sparse representation. Experiments on synthetic data validate the effectiveness of the proposed method by comparing it with existing lossy matrix compression methods

Patterns of Consensus Building in Research Meetings for Elementary-School Physical Education Teachers: Focusing on Problem Solving Situations

本研究の目的は，小学校の体育研究主任研究会において課題分析をする際に，教師がどのような合意形成パターンを取りながらコミュニケーションしていくのかを明らかにすることである．「コンセンサス」と「アコモデーション」という2つの「合意形成」概念を視点に会話分析した結果，6個の合意形成パターンを抽出することができた．「コンセンサス」をめぐる合意形成では，「単語の共有」，「言い換えによる納得」が抽出され，「アコモデーション」をめぐる合意形成では，「実体験への共感」，「概念をめぐる差異の許容」，「つぶやきの強化」，「視点の転換」が抽出された．これらの概念を合意される内容（「コンセンサス」，「アコモデーション」）を縦軸，話題への参加構造（「単線的」，「複線的」）を横軸にとる合意形成パターン構造に整理した．このことにより，教員研修内の発話がどのようになされているのかを認識する枠組みを提示することができた．The purpose of this study is to elucidate the kinds of patterns of consensus building employed by teachers in communication during analysis of issues in physical education classes conducted in research meetings for elementary-school physical education teachers. Grounded in the perspective of social constructivism, which holds that people’ s understandings are determined by consensus achieved through dialogue, conversational analysis was conducted regarding group discussions conducted during research meetings for elementary-school physical education teachers, employing as analytical perspectives the two consensusbuilding concepts of consensus and accommodation. From the results of analysis, six concepts could be identified from teachers’ patterns of consensus building. Patterns of communication identified with regard to consensus were sharing of terminology and assent through rephrasing, while patterns of communication identified with regard to accommodation were sharing of real-world experiences with humor, tolerance of differences regarding abstract concepts, emphasis by grumbling, and diversion of perspectives through rephrasing questions. Furthermore, these concepts were plotted in four quadrants along two axes, with the results of agreement (consensus, accommodation) on the vertical axis and the structures of participation in dialogue (unilinear, multilinear) on the horizontal axis. This suggested possibilities for use in facilitation of groupwork in teacher training

Transforming Teachers’ Attitudes through Experiential Learning in Laos -BENGALA dying workshops and the experience with local teachers-

　ラオスの学校制度は, 初等教育全般において「体験型学習の提供」を求めている。実技教科では体験型の授業が実践されているが, それ以外の教科では座学中心の授業である。その背景には, 体験型学習の行い方がわからないといった教員の課題意識がある。本研究では, 特に教員の授業づくりに対する課題意識を引き受け, ラオスにおいて体験型学習を協働実践し教員意識の変容を明らかにすることとした。具体的には, ラオスの小中学校２校で,体育の授業で使うT シャツをベンガラ染めする体験型学習を行った。教員にも参加してもらいながら, 体験型学習を経験すると同時に協働実践することで, どのように意識が変容するかを検証した。検証方法は, 実践校２校の教員に対する半構造化インタビューである。その結果, 教員らは体験型学習の可能性を理解した一方, 座学中心の授業から体験型学習へ転換の方法がわからないという意見もあり, 今後の課題となった。The Lao school system calls for the "provision of experiential learning" in all aspects of primary education. However, while hands-on learning is practiced in practical subjects, other subjects remain classroom-based. One of the reasons for this is the teachers' awareness that they do not know how to conduct hands-on learning. In this PBL, we took on the problem consciousness of Laotian teachers in particular regarding class creation and clarified how teachers' consciousness would change through the collaborative implementation of experiential learning in Laos. Specifically, we conducted hands-on workshops at two elementary schools in Laos to dye T-shirts for physical education classes as part of the emotional education program. Teachers were also invited to participate in the bengara-dyeing workshop, and we examined how their awareness was changed through the experience of hands-on learning and collaborative practice. Semi-structured interviews were conducted with teachers at the two schools where the workshop was conducted. The results showed that the teachers viewed the workshop positively in regarding the interaction with foreign visitors and enjoyment and fun through learning. While they understood the potential of experiential learning, some of them did not know how to convert their classroom-based courses to include this form of experiential learning, which is an issue to be addressed in the future

“KNOWLEDGE CREATION” in the “Comprehensive Learning Period” : Possibilities and Challenges in Making Sports Culture Themes

本研究の目的は，総合的な学習の時間において知識創造することの重要性を示すと同時に，社会構成主義の知識観に立脚しスポーツ文化をテーマにすることの理論的可能性を検討することと，実践する際に生じうる課題について言及することである。その結果，総合的な学習の時間において児童生徒が新たな知識を創造することが学習観の転換につながり，「結果（内容）／過程」という二分法の議論を乗り越えられる可能性が示された。また，「ゆるスポーツ」や「スポーツ共創」といったスポーツを新たに創るという営みをテーマにした際に，それぞれのスポーツがどのような「コト」に挑戦するのかを明確にすることで，実感を伴った知識創造を生みだしやすいことが理論的に導かれた。ただし実際に実践する際には，教師が調べ学習のイメージを強く持っていることから，何をもって「知識創造」したと認識しうるのか，またその質のばらつきが学習成果に影響を及ぼすことが課題である