研究者詳細 - 金子　晋丈

論文 - 金子　晋丈

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Local community detection by random walk on hypergraphs

Oka R., Matsumoto N., Takai Y., Ikeda M., Kaneko K.

Communications in Statistics - Theory and Methods （Taylor & Francis） 1 - 20 2025年07月

研究論文（学術雑誌）, 共著, 最終著者, 査読有り, ISSN 03610926

Hypergraphs have been attracting more attention because they are suitable for representing real-world networks with complex relations of three or more terms. Clustering hypergraphs is a fundamental task in network analysis. Although several algorithms for finding a community with a theoretical guarantee are already known, almost all require information on the entire hypergraph for calculation. In this study, we propose a personalized PageRank random walk on a hypergraph and an algorithm for hypergraphs to extract a local community, which can be calculated purely locally. We experimentally show that the algorithm outperforms a benchmark method for real-world hypergraphs. We also evaluate the matching rates with the local community and weak ties using F<inf>1</inf>-scores while varying several parameters for a synthetic hypergraph generated by a stochastic block model.

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Weighted APPR with restart for community extraction from multilayer networks

Nakano S., Yamashita T., Shin A., Matsumoto N., Kaneko K.

Knowledge and Information Systems （Springer） 1 - 21 2025年06月

研究論文（学術雑誌）, 共著, 最終著者, 査読有り, ISSN 02191377

Community extraction is widely used for various applications concerning network analysis, but its scope has mostly been confined to single-layer network. However, the real-world data are frequently represented as multilayer network, and furthermore, each layer frequently exhibits different properties. It is thus critical to be able to control to what degree each layer should be reflected in the overall network, in order to perform a reliable community extraction. In this paper, we propose a superimposition method called WAPPRS (weighted APPR with restart) that can monotonically increase the degree of reflection and handle a wide range of values for reflection. Our experiments demonstrate that our proposed model outperforms previous models when dealing with the properties desirable for reliable community extraction from multilayer networks.

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Balancing Global Importance and Source Proximity for Personalized Recommendations Using Random Walk Length

Yamashita T., Kaneko K.

Lecture Notes in Computer Science （Springer） 15669 141 - 153 2025年05月

研究論文（国際会議プロシーディングス）, 最終著者, 査読有り, ISSN 03029743

For personalized recommendation in graphs, random walks starting from the user’s interest node are known as a general-purpose and fast analysis method. Specifically, Personalized PageRank (PPR), which quantifies the importance of each node by the distribution of visited nodes in random walks, determines nodes with high global importance and source proximity. However, it is difficult to balance both influences monotonically. This paper clarifies that the random walks length is effective to monotonically control the balance of both influences on PPR vectors. In particular, we exploit the fact that correlation between PPR and PageRank values monotonically changes depending on PPR parameter that controls the average random walk length. Here, PageRank is a metric that quantifies the global importance by the probability of random walks from all nodes visiting each node. A case study using the movie rating dataset showed that nodes that are considered to be directly related to the source node get high PPR value by shortening the average random walk length. Moreover, statistical evaluation on nine real-world datasets revealed that changing the average random walk length from 1.01 to 100 resulted in a monotonic increase of the cosine similarity between PPR and PageRank vectors from 0.002 to 0.76 at the maximum.

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Reducing Re-Indexing for Top-k Personalized PageRank Computation on Dynamic Graphs

Yamashita T., Matsumoto N., Kaneko K.

IEEE Transactions on Big Data （IEEE） 11 （ 4 ） 1707 - 1719 2025年01月

研究論文（学術雑誌）, 共著, 最終著者, 査読有り

Top-k Personalized PageRank (PPR) is a graph analysis method used to determine the k most important nodes with respect to a source node. To realize fast Top-k PPR computation, indexing for each node is effective. When we apply the index-based Top-k PPR methods to dynamic graphs, the index becomes stale with edge updates, and index correction is required. Although the existing methods perform index correction for every update to guarantee Top-k PPR accuracy, they involve heavy re-indexing computation or significant memory overhead. This paper proposes a method that achieves comparable accuracy to guaranteed methods while significantly reducing re-indexing by focusing on the fact that index references are concentrated on the nodes whose index is unlikely to change due to edge updates. In particular, our method omits re-indexing as long as we achieve comparable accuracy. Furthermore, our method involves the minimum memory overhead among the existing index-based methods. The space complexity of the index is Θ (n + m), where n and m are the number of nodes and edges of the graph, respectively. The evaluation results using real-world datasets show that our method achieves more than 0.999 Normalized Discounted Cumulative Gain until 20% of edges are updated from index generation.

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A Flexible Weighting Framework For Converting Relational Database To Hypergraphs

Fujii K., Yamashita T., Shin A., Kaneko K.

International Conference on Information Networking （IEEE Computer Society） 607 - 612 2025年

研究論文（国際会議プロシーディングス）, 共著, 最終著者, 査読有り, ISSN 19767684

We propose a framework for converting relational databases (RDB) into hypergraphs to adjust and output various PageRank (PR) correlations by weighting hyperedges and nodes. While analyzing PR of converted graphs can reveal multifaceted information about relationships in the data, conventional methods struggled to balance the correlations between node PR and degree (NPR correlation) and edge PR and shared field records (EPR correlation). Our approach introduces two exponential weighting parameters: α for edge size, influencing EPR correlation, and β for node degree, influencing NPR correlation. By adjusting these parameters, various PR correlations can be obtained. Evaluation using real-world data demonstrate that our model can convert RDBs into hypergraphs with flexibility.

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Large Language Models Lack Understanding of Character Composition of Words

Shin A., Kaneko K.

Proc. of ICML Workshop on Large Language Models and Cognition abs/2405.11357 1 - 11 2024年07月

研究論文（国際会議プロシーディングス）, 共著, 最終著者, 査読有り

Large language models (LLMs) have demonstrated remarkable performances on a wide range of natural language tasks. Yet, LLMs' successes have been largely restricted to tasks concerning words, sentences, or documents, and it remains questionable how much they understand the minimal units of text, namely characters. In this paper, we examine contemporary LLMs regarding their ability to understand character composition of words, and show that most of them fail to reliably carry out even the simple tasks that can be handled by humans with perfection. We analyze their behaviors with comparison to token level performances, and discuss the potential directions for future research.

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Fast Personalized PageRank for Customized Analysis Range Using Static Index

Yamashita T., Kaneko K.

Proc. of the 15th International Conference on Ubiquitous and Future Networks （IEEE） 304 - 309 2024年07月

研究論文（国際会議プロシーディングス）, 共著, 最終著者, 査読有り, ISSN 21658528

PPR is an essential computation for customized graph analysis, and its fast computation methods have been proposed. FORA +, one of the fastest methods, introduces an index to speed up PPR computation by referencing the end nodes of pre-generated random walks with a specific termination probability αindex. Although for customized graph analysis, it is essential to query with different termination probabilities α for controlling the analysis range, FORA + does not contribute to the speedup for such different α other than the αindex. This paper proposes a method to quickly determine the end nodes of random walks for arbitrary termination probabilities α(≤ αindex) by focusing on the fact that the random walks become probabilistically longer as the termination probability decreases. In particular, we repeatedly reference the index based on the probability p defined by αindex and α to make the longer random walks. By defining p according to mathematical considerations, the results of our method are guaranteed. In addition, our method can be used in FORA + without modifying its index structure. We incorporate our method into FORA + and evaluate the processing time using six real-world graph datasets. As a result, our method achieves up to 19.8 times speedup over the existing index-free method.

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The Lost Melody: Empirical Observations on Text-to-Video Generation From A Storytelling Perspective.

Shin A., Mori Y., Kaneko K.

Proc. of CVPR 2024 Workshop on AI for Content Creation (AI4CC) abs/2405.08720 1 - 12 2024年05月

研究論文（国際会議プロシーディングス）, 共著, 査読有り

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Minimum Steiner Tree Approximation for Extracting Unknown Information via Avoiding High-Centrality Nodes

Nishiyama R., Shin A., Matsumoto N., Kaneko K.

Proc. of the 38th International Conference on Information Networking (ICOIN) （IEEE） 2024-January 581 - 586 2024年01月

研究論文（国際会議プロシーディングス）, 共著, 最終著者, 査読有り, ISSN 19767684

Minimum Steiner tree is frequently used as a means for information retrieval, particularly for search with keyword. While it tends to include high-centrality nodes, the information obtained from such tree may already be accessible to the user, which is not very useful. In this paper, we propose a Steiner tree that avoids high-centrality nodes, in order to increase the likelihood of information being unknown to the user, and thus more useful, while maintaining a high degree of relevance to the keywords. We examine various schemes to select high-centrality nodes to avoid, and compare them in terms of the degree of relevance with the keyword, probability of being unknown to the user, and the pre-computation time. We employ degree centrality and betweenness centrality as our metric for centrality. We find that, our best-performing scheme, despite its simplicity, is able to reduce more than 5% in terms of the number of betweenness centrality nodes compared to the minimum Steiner tree, along with its pre-computation time being about 20% times faster, regardless of our choice of centrality metric.

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Cache-Efficient Approach for Index-Free Personalized PageRank

Tsuchida K., Matsumoto N., Shin A., Kaneko K.

IEEE Access （IEEE） 11 6944 - 6957 2023年01月

研究論文（学術雑誌）, 共著, 最終著者, 査読有り

Personalized PageRank (PPR) measures the importance of vertices with respect to a source vertex. Since real-world graphs are evolving rapidly, PPR computation methods need to be index-free and fast. Unfortunately, existing index-free methods suffer from cache misses. They follow the state-of-the-art algorithm that first performs the Forward Push (FP) phase and subsequently runs the random walk Monte-Carlo simulation (MC) phase. Although existing methods succeed in reducing cache misses in the FP phase, an inefficient data layout limits their performance improvement. Besides, existing methods have overlooked the importance of reducing cache misses in the MC phase. In this paper, we propose a cache-efficient approach that accelerates both FP and MC phases. In the FP phase, we first reorder the data layout with low overheads. Specifically, we utilize the Breadth First Search result so that vertices near the source vertex are co-located on the reordered data layout. We subsequently perform optimized FP, namely Distance-Extension Forward Push (DEFP). By preferentially proceeding FP around the source vertex, DEFP improves memory access locality. In the MC phase, we perform optimized MC, namely Vertex-Centric Random Walk (VCRW). VCRW aggregates random walks at each vertex to eliminate redundant memory access for repeatedly obtaining neighbor vertices. We prove that most of the random walks can be aggregated while maintaining accuracy guarantees. Experimental results show that the proposed method is up to 4.7x faster than existing index-free methods and outperforms the state-of-the-art index-oriented method under rigorous accuracy guarantees.

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Node-Centric Random Walk for Fast Index-Free Personalized PageRank

Tsuchida K., Matsumoto N., Kaneko K.

Proc. of International Conference on Information Networking （IEEE） 2023-January 194 - 199 2023年01月

研究論文（国際会議プロシーディングス）, 共著, 最終著者, 査読有り, ISSN 19767684

Personalized PageRank (PPR) is a popular graph computation in various real-world applications. Since massive real-world graphs are evolving rapidly, PPR computation methods require index-free and fast. In general, index-free methods go through Forward Push phase and random walk Monte-Carlo simulation phase respectively. While existing methods have succeeded in accelerating the Forward Push phase, there is a space for running-time improvements in the second phase that performs a large number of sequential random walks. Through this sequential process, each random walk needs to obtain neighbor nodes for every single step, which causes redundant operation at each node as a result. Our proposal is a node-centric random walk that aggregates random walks at each node and minimizes the total number of obtaining neighbor nodes in the second phase. Most of the random walks can be aggregated while maintaining theoretical guarantees because they do not need to memorize the starting node. In addition, we review the expected running time of random walk Monte-Carlo simulation focusing on the total number of obtaining neighbor nodes. We conducted extensive experiments using four real-world graphs. Experimental results showed that our proposed method is up to 3.3x faster than the existing methods.

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WalkOrder: Combining Graph Sampling and Reordering for Fast Computation

Tsuchida K., Kaneko K.

Proc. of International Conference on Scientific Computing （American Council on Science & Education） 1 - 13 2022年07月

研究論文（国際会議プロシーディングス）, 共著, 最終著者, 査読有り

A smaller graph sampled from a large graph uses an excessively wide range of vertex IDs beyond its graph size, which causes a sparse layout on memory. Gorder is a state-of-the-art graph reordering technique for layout optimization. However, despite providing performance improvement, applying Gorder to a sampled graph requires lengthy and impractical time periods,such as reordering time and waiting time for the completion of sampling. In addition, it is unsuitable for multicore graph computation because high and low degree vertices are separated on memory by reordering. We propose WalkOrder, a technique that conducts gradual graph reordering in parallel with sampling; sampling is performed by the widely used Metropolis-Hastings Random Walk. WalkOrder reduces reordering costs of Gorder and balances workload between cores. Our extensive experiments on six real-world graphs revealed that WalkOrder was faster than baseline techniques by an average of 1.52 times and a maximum of 1.95 times.

オープンなデジタルミュージアムー多様な価値の共存と高い規模拡張性

金子　晋丈

デジタルアーカイブ・ベーシックス4 アートシーンを支える（勉誠出版） 203 - 217 2020年11月

論文集(書籍)内論文, 単著, 筆頭著者, 最終著者, 責任著者, 査読有り

Inserting layer-5 to provide applications with richer functions through common API

Watanabe H., Kondo T., Kaneko K., Teraoka F.

IEICE Transactions on Communications （IEICE） E101-B （ 9 ） 1967 - 1981 2018年09月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 09168516

Recently, application demands placed on the network have become more multifaceted. Highly functional application-to-application communication services such as bandwidth aggregation, fault tolerant communication, and delay/disruption tolerant networking (DTN) were developed independently in the network layer, the transport layer, and the application layer. As a result, protocol layering has become complicated. This paper proposes to insert Layer-5 (L5) between the application layer and the transport layer to separate communication policies and communication mechanisms to make protocol layering clearer. The transport layer (L4) provides end-to-end communication mechanisms such as reliable byte stream while L5 realizes communication policies such as bandwidth aggregation by combining the communication mechanisms in L4. This paper proposes five types of L5-paths as communication policies: (1) the L5 bundled path for bandwidth aggregation or fault tolerant communication, (2) the L5 spatially-spliced path for communication with middleboxes, (3) the L5 temporally-spliced path for DTN, (4) the L5 spliced-bundled path, and (5) the L5 bundled over spatially-spliced path. An application can select and use an appropriate L5-path depending on the network circumstances through a common API. A prototype of L5 is implemented in the Linux user space as a library to make deployment and maintenance easier. An evaluation shows that establishment time of L5-paths is short enough and performance of L5-paths is comparable or superior to existing technologies.

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Activation server for bidirectional limited usages of digital objects

Ogitani R., Kaneko K.

Proceedings IEEE 16th International Conference on Dependable Autonomic and Secure Computing IEEE 16th International Conference on Pervasive Intelligence and Computing IEEE 4th International Conference on Big Data Intelligence and Computing and IEEE 3rd Cyber Science and Technology Congress Dasc Picom Datacom Cyberscitec 2018 （IEEE） 1008 - 1015 2018年08月

研究論文（国際会議プロシーディングス）, 共著, 最終著者, 査読有り

Limiting data usage is an important issue for data sharing. Big data, in particular, has numerous potential values; thus, an arbitrary value can be extracted as an output by processing data with an arbitrary program. If a data provider simply shares his data with users, the users may get information that the data provider does not want to disclose. However, currently, there is no mechanism to limit the usage of such data. In our approach, a data provider and a program provider specify a combination of data and program files bidirectionally to limit their usages. The Activation Server binds the specified data and program, and then the Activation Server processes the data with the program and sends the output to the user specified by the data provider. We assume that a third-party organization has certified the security for the Activation Server. We implemented and evaluated the Activation Server to demonstrate that it enables data sharing by limiting the usage of digital objects.

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ZINK: An efficient information centric networking utilizing layered network architecture

Kondo T., Yoshihara S., Kaneko K., Teraoka F.

IEICE Transactions on Communications （IEICE） E101-B （ 8 ） 1853 - 1865 2018年08月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 1745-1345

This paper argues that a layered approach is more suitable for Information CentricNetworking (ICN) than a narrow-waist approach and proposes an ICN mechanism called ZINK. In ZINK, a location-independent content name is resolved to a list of node IDs of content servers in the application layer and a node ID is mapped to a node locator in the network layer, which results in scalable locator-based routing. An ID/Locator split approach in the network layer can efficiently support client/serever mobility. Efficient content transfer is achieved by using sophisticated functions in the transport layer such as multipath transfer for bandwidth aggregation or fault tolerance. Existing well-tuned congestion control in the transport layer achieves fairness not only among ICN flows but also among ICN flows and other flows. A proof-of concept prototype of ZINK is implemented on an IPv6 stack. Evaluation results show that the time for content finding is practical, efficient content transfer is possible by using multipath transfer, and the mobility support mechanism is scalable as shown in a nationwide experiment environment in Japan.

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Polymorphic cataloguing and interactive 3D visualization for multiple context of digital content: MoSaIC

Ishikawa H., Kaneko K.

Lecture Notes in Computer Science （Springer） 10714 172 - 186 2017年12月

研究論文（国際会議プロシーディングス）, 共著, 最終著者, 査読有り, ISSN 03029743

In this paper, we propose two methods of interactive visualization of the MoSaIC catalogue. We proposed a conceptual modeling for manifold relationships among digital content files as polymorphic catalogues and its visualization system (MoSaIC-II) before. In the modeling, two structures are provided to express the relationships. One is “grouping objects”. The other is “associating between two objects”. The relationship is constructed by using the combination of two structures, and it is described by using directed graph called a MoSaIC catalogue. Multiple catalogues can be connected by shared objects polymorphically. To visualize the catalogue, we propose two methods which are polymorphic topology view and layer view in MoSaIC system using 3D computer graphics. In the previous method, some objects might be overlapped depending on object connections. Then a lot of objects and complex connection of edges can users feel complicated. Using the new methods, object overlap and the complexity of catalogue and object connections can be improved. In the polymorphic topology view, users can see topology of connected objects avoiding object overlaps. Furthermore, we propose the layer view to show objects aligned by a catalogue creator. In the layer view, users can see connected objects which are aligned and exhibited on each catalogue layer. In this method, a complex connection of edges is improved and comparatively a lot of objects can be handled.

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Content espresso: A distributed large file sharing system for digital content productions

Ando D., Teraoka F., Kaneko K.

IEICE Transactions on Information and Systems （IEICE） E100-D （ 9 ） 2100 - 2117 2017年09月

研究論文（学術雑誌）, 共著, 最終著者, 査読有り, ISSN 1745-1361

With rapid growth of producing high-resolution digital contents such as Full HD, 4K, and 8K movies, the demand for low cost and high throughput sharing of content files is increasing at digital content productions. In order to meet this demand, we have proposed DRIP (Distributed chunks Retrieval and Integration Procedure), a storage and retrieval mechanism for large file sharing using forward error correction (FEC) and global dispersed storage. DRIP was confirmed that it contributes to low cost and high throughput sharing. This paper describes the design and implementation of Content Espresso, a distributed large file sharing system for digital content productions using DRIP, and presents performance evaluations. We set up experimental environment using 79 physical machines including 72 inexpensive storage servers, and evaluate file metadata access performance, file storage/retrieval performance, FEC block size, and system availability by emulating global environments. The results confirm that Content Espresso has capability to deal with 15,000 requests per second, achieves 1 Gbps for file storage, and achieves more than 3 Gbps for file retrieval. File storage and retrieval performance are not significantly affected by the network conditions. Thus, we conclude that Content Espresso is capable of a global scale file sharing system for digital content productions.

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PTP accuracy measurement comparison between boundary clock and VLAN priority

Horita K., Shiobara S., Okamawari T., Teraoka F., Kaneko K.

Proc. of 2017 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS) （IEEE） 53 - 58 2017年08月

研究論文（国際会議プロシーディングス）, 共著, 最終著者, 査読有り, ISSN 19490305

IEEE1588 (PTP: Precise Time Protocol), which aims for the sub-microsecond range of clock synchronization in a minimal network, is currently focused on highly precise clock synchronization. Boundary Clock (BC) and VLAN Priority are considered to be features that improve PTP accuracy. Although some papers addressed the accuracy, these evaluations were realized using different evaluation metrics and environments. We make them comparable to analyse the contribution of BC and VLAN Priority to precise clock synchronization. Our accuracy evaluation used PTP nodes available on the market and shows the results following the test cases defined in the ITU-T G.8261 Recommendation and IEEE1588 standard. The measurement results show that the accuracy was better than 200 nanoseconds with BC enabled, while it was about one microsecond with BC disabled. We observed that the accuracy was improved to approximately 850 nanoseconds when VLAN Priority was enabled.

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Separating communication policies and mechanisms to make protocol layering clearer

Watanabe H., Kondo T., Kaneko K., Teraoka F.

Proc. of the 26th International Conference on Computer Communication and Networks (ICCCN 2017) （IEEE） 1 - 9 2017年07月

研究論文（国際会議プロシーディングス）, 共著, 査読有り

Recently, applications' demands for the network become more multifaceted. Highly functional application-to- application communication services such as bandwidth aggregation, fault tolerant communication, and delay/disruption tolerant networking (DTN) were developed independently in the network layer, the transport layer, and the application layer. As a result, protocol layering has become complicated. This paper proposes Layer-5 (L5) inserted between the application layer and the trans- port layer to separate communication policies and communication mechanisms to make protocol layering clearer. The transport layer (L4) provides end-to-end communication mechanisms such as reliable byte stream while L5 realizes communication policies such as bandwidth aggregation by combining the communication mechanisms in L4. This paper proposes five types of L5-paths as communication policies: (1) the L5 bundled path for bandwidth aggregation or fault tolerant communication, (2) the L5 spatially- spliced path for communication with middleboxes, (3) the L5 temporally-spliced path for DTN, (4) the L5 spliced- bundled path, and (5) the L5 bundled over spatially-spliced path. An application can select and use an appropriate L5- path depending on the network circumstances through a common API. A prototype of L5 is implemented in the Linux user space as a library to make deployment and maintenance easier. The evaluation shows that establishment time of L5- paths is short enough and performance of L5-paths is comparable or superior to existing technologies.

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Layer-5 temporally-spliced path for efficient Disruption Tolerant Networking

Mitake D., Kaneko K., Teraoka F.

Proc. of 2017 IEEE International Symposium on Local and Metropolitan Area Networks (LANMAN) （iEEE） 1 - 6 2017年06月

研究論文（国際会議プロシーディングス）, 共著, 査読有り

DTN (Delay/Disruption Tolerant Networking) inserts a new layer between the application layer (L7) and the transport layer (L4) for reliable communication on long-delay, intermittent, or lossy inks. Such a new layer, however, should provide not only a single rich service but also various rich services. We are proposing Layer-5 (L5) inserted between L7 and L4 to provide multiple rich services. One of the rich services of L5 is the L5 temporally-spliced path (L5-TSP). It is an application-to-application path composed of multiple L4 paths, which may not exist at the same time, spliced in L5 in the nodes called splicers. This paper proposes L5-TSP Protocol (L5-TSPP) for reliable communication on lossy links. L5-TSPP places splicers at both ends of a lossy link. It uses TCP on reliable links while UDP on lossy links. It uses partial acknowledgement to enable end nodes to know progress of communication. L5-TSPP is implemented on Linux. It takes 61 msec for connection establishment in L5-TSPP while 530 msec in TCP at packet loss rate of 10 % on a lossy link. It takes 18 sec to send a 1GB file in L5-TSPP while 73 sec in TCP at packet loss rate of 1 %.

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Improving file sharing performance for web-based collaboration systems by using content espresso

Ando D., Leigh J., Teraoka F., Kaneko K.

Proc. of the 12th Asian Internet Engineering Conference (AINTEC 2016) （Association for Computing Machinery） 33 - 40 2016年11月

研究論文（国際会議プロシーディングス）, 共著, 最終著者, 査読有り

Remote collaboration work via the Internet becomes common these days by appearance of web-based remote collaboration systems such as Google Apps, and SAGE2. This paper focuses on SAGE2 as a typical data intensive collaboration system, which shares information on large highresolution displays with other sites using web browser technologies. However, it takes long time to share large files between SAGE2 systems. In order to improve the file sharing performance of SAGE2, this paper proposes a file sharing mechanism using Content Espresso, a distributed storage system for global large file sharing, which can be applied to other web-based collaboration systems. We implemented and evaluated the proposed mechanism by emulating a global network environment. The result of the evaluation confirms that the proposed mechanism has better performance than the existing file sharing mechanism on SAGE2 when RTT between SAGE2 systems is longer than 10 ms.

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Verification of a multi-domain authentication and authorization infrastructure yamata-no-orochi

Mikami K., Ando D., Kaneko K., Teraoka F.

Proc. of the 11th International Conference on Future Internet Technologies (CFI2016) （Association for Computing Machinery） 69 - 75 2016年06月

研究論文（国際会議プロシーディングス）, 共著, 査読有り

Yamata-no-Orochi is an authentication and authorization infrastructure across multiple service domains and provides Internet services with unified authentication and authorization mechanisms. In this paper, Yamata-no-Orochi is incorporated into a video distribution system to verify its general versatility as a multi-domain authentication and authorization infrastructure for Internet services. This paper also reduces the authorization time of Yamata-no-Orochi to fulfill the processing time constrains of the video distribution system. The evaluation results show that all the authentication and authorization processes work correctly and the performance of Yamata-no-Orochi is practical for the video distribution system.

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Fast handover mechanism for high data rate ground-to-train free-space optical communication transceiver for internet streaming applications

Mori K., Terada M., Yamaguchi D., Nakamura K., Kaneko K., Teraoka F., Haruyama S.

IEICE Transactions on Communications （IEICE） E99-B （ 5 ） 1206 - 1215 2016年05月

研究論文（学術雑誌）, 共著, 査読有り

There is a strong demand to enjoy broadband and stable Internet connectivity not only in office and the home but also in high-speed train. Several systems are providing high-speed train with Internet connectivity using various technologies such as leaky coaxial cable (LCX),Wi-Fi, and WiMAX. However, their actual throughputs are less than 2 Mbps. We developed a free-space optical (FSO) communication transceiver called LaserTrainComm2014 that achieves the throughput of 1 Gbps between the ground and a train. LaserTrainComm2014 employs a high-speed image sensor for coarse tracking and a quadrant photo-diode (QPD) for accurate tracking. Since the image captured by the high-speed image sensor has several types of noise, image processing is necessary to detect the beacon light of the other LaserTrainComm2014. As a result of field experiments in a vehicle test course, LaserTrainComm2014 achieves handover time of 21 milliseconds (ms) in the link layer at the speed of 60 km/h. Even if the network layer signaling takes time of 10 milliseconds, the total communication disruption time due to handover is short enough to provide passengers with Internet connectivity for live streaming Internet applications such as YouTube, Internet Radio, and Skype.

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Intra-AS performance analysis of distributed mobility management schemes

Erunika O., Kaneko K., Teraoka F.

IEICE Transactions on Information and Systems （IEICE） E98-D （ 8 ） 1477 - 1492 2015年08月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 09168532

Distributed Mobility Management (DMM) defines Internet Protocol (IP) mobility which does not depend on centralized manipulation. DMM leads to the abatement of non-optimal routing, a single point of failure, and scalability problems appearing in centralized Mobility Management (MM). The fact that most DMM schemes are in the proposal phase and non-existence of a standardization, urge to investigate the proposed schemes thoroughly to confirm their capabilities and thereby, to determine the best candidate practice for DMM. This paper examines five novel DMM proposals discussed in the Internet Engineering Task Force (IETF) using router-level Internet Service Provider (ISP) topologies of Sprint (USA), Tiscali (Europe), Telstra (AUS), and Exodus (USA), as user mobility within an ISP network is considered the most realistic and recurrent user movement in the modern scope. Results reflect behavioral differences of schemes depending on the network. ISPs closer to the Internet core with high density of Point of Presences (PoPs) such as Sprint show poorer outcome when centralized anchors/controllers are employed while Proxy Mobile IP (PMIP) based enhancements offer higher reliability. In contrast, smaller ISPs that reside farther away from the Internet core yield better performance with SDN-Based and Address Delegation schemes. Although the PMIP-Based DMM schemes perform better during handover, their outturn is trivialized due to higher latency in the data plane. In contrast, the Address Delegation and SDN-Based schemes have excessive cost and latency in performing handover due to routing table updates, but perform better in data plane, suggesting that control/data plane split may best address the optimal routing.

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Content Espresso: Dispersed Storage for High-speed Network Access to Large-size Image Files

Kaneko K., Ando D., Yamagishi T., Sano T., Teraoka F.

Proc. of the 1st International Conference on Advanced Imaging （The Imaging Society of Japan） 35 - 38 2015年06月

研究論文（国際会議プロシーディングス）, 共著, 筆頭著者, 責任著者, 査読有り

As the quality of digital image is getting higher, the size of the images is getting larger. For example, an uncompressed 8bit HD color image file exceeds 6MB. Therefore, when we store and access large image files through network, high-speed storage I/O, CPU, and network are required. However, the state-of-the-art storage system is very expensive. Our dispersed networked storage system called Content Espresso consisting of off-the-shelf computers with Forward Error Correction and UDP-based delivery mechanisms realizes high-speed access to the stored large files. Our proof of concept prototype realized a series of HD uncompressed image files delivery from Tokyo to San Diego and accomplished a video playback at least 24 fps frame rate.

Construction of routing information knowledge base towards wide area network management

Ohshima R., Kawaguchi S., Kamatani O., Akashi O., Kaneko K., Teraoka F.

Proc. of the 10th International Conference on Future Internet (CFI2015) （Association for Computing Machinery） 76 - 83 2015年06月

研究論文（国際会議プロシーディングス）, 共著, 査読有り

Nowadays each network management system (NMS) adopts different methods for collecting network information and different data structures. This makes NMS cooperation difficult, especially in multi-AS wide area network management. The current goal of the KANVAS (Knowledge base system in wide Area Networks with general Versatility, Availability and Scalability) project is to realize wide area network management by constructing a knowledge base system in networks. This paper discusses construction of a knowledge base system in a single AS (Autonomous System) towards the future wide area network management. This paper also shows the design and implementation of the knowledge base system that collects network configuration information from OSPF and SNMP, and stores it as instances of our proposed network ontology called Bonsai. Additionally, a prototype application that accesses the stored knowledge was implemented. The evaluation of basic performance and scalability of the system was carried out using a real AS topology and synthetic topologies and it was made sure that the prototype application works correctly. As a result, this paper shows that feasibility of the future wide area network management that adopts the knowledge base system.

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Catalogue: Graph representation of file relations for a globally distributed environment

Miyashita Y., Ishikawa H., Teraoka F., Kaneko K.

Proc. of the 30th Annual ACM Symposium on Applied Computing (SAC 2015) （Association for Computing Machinery） 806 - 809 2015年04月

研究論文（国際会議プロシーディングス）, 共著, 最終著者, 査読有り

Text-based search engines are widely used to find files in the Internet. However, the users require to understand contexts existing in files and notice appropriate keywords even if the users do not have deep insights of the topic. In addition, text-based search engines require exhaustive search to make keyword indexes. This paper proposes the concept of catalogue that represents relations among files based on grouping and associating by a directed graph. Grouping of files by a catalogue without any text label lets us notice some relations represented by the catalogue. Moreover, a directed graph within a catalogue which associates files can express more detailed relations. We design catalogue system that stores and shares catalogues globally in a distributed and autonomous way. Generalized graph expression of catalogues shared over the Internet bridges any owners, types, and fields of files as long as the files share a same relation. Various services such as digital museums and digital archives are expected to work on top of the shared catalogues.

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Performance evaluation of host-based mobility management schemes in the internet

Erunika O., Kaneko K., Teraoka F.

Proc. of the Eighth International Conference on Mobile Computing and Ubiquitous Networking (ICMU 2015) （IEEE） 173 - 178 2015年01月

研究論文（国際会議プロシーディングス）, 共著, 査読有り

The literature lacks theoretical and practical evaluations of Distributed Mobility Management (DMM) schemes which aim to mitigate disadvantages of conventional centralized schemes such as a single point of failure, congestion in home network, and limited scalability. This paper selects Global HAHA, Migrating HA, and Distributed Mobile IP (DMIP) as representative host-based decentralized Internet Mobility Management (MM) schemes, and probes their control and data planes against Mobile IP (MIP) and MIP with Return Routability procedure (MIPRR), using real Autonomous System (AS) level topology data of the Internet. By using different combinations of MM Agent (MMA) placements, random sessions are investigated for host mobility in terms of the total number of hops and the AS load. Comparison of generic results shows that DMIP and Migrating HA outperform the legacy schemes. Further, DMIP overcomes consistency maintenance and scalability problems seen in Migrating HA, maintaining much similar performance, while achieving reliability eliminating an expensive controlling overhead as in MIPRR.

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Polymorphic cataloguing and viewing system for using digital archives: MoSaIC-II

Ishikawa H., Saito H., Miyashita Y., Kaneko K.

Proc. of the 20th International Conference on Virtual Systems & Multimedia (VSMM2014) （IEEE） 176 - 179 2014年12月

研究論文（国際会議プロシーディングス）, 共著, 最終著者, 査読有り

We propose a digital content viewing system which visualizes the polymorphic relationships among digital content interactively and uses it as a visual interface. The relationships are expressed by associating of two content and grouping and shown by directed graphs. On the graphs, nodes mean the content files or the groups, and edges mean correspondences or group members. The graphs are archived as relation catalogues separately from content files. We visualize the relations of content on a directed graph. To visualize the graphs, we use a method of locating nodes by horizontal directions and height. Nodes linked with a target node will be located on a horizontal circle and their height is decided by their relation catalogue. After deciding the node location, nodes and links are drawn using 3D graphics and animation. The visualization result called 'polymorphic view' is used as a visual interface for selecting content. Selecting content on the visualized graph will expand new links and new content nodes additionally. We can show another content by tracing graph links. It becomes easy to understand the relations between digital content, because we can change the direction and size of the directed graph. We developed a content viewer system (MoSaIC-II) using the polymorphic view as a visual interface and we can see the usability of the polymorphic view.

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ZNA: A six-layer network architecture for new generation networks - Focusing on the session layer, the network layer, and cross-layer cooperation

Teraoka F., Kanemaru S., Yonemura K., Ide M., Kawaguchi S., Kaneko K.

IEICE Transactions on Communications （IEICE） E97-B （ 12 ） 2583 - 2595 2014年12月

研究論文（学術雑誌）, 査読有り, ISSN 09168516

Using "clean-slate approach" to redesign the Internet has attracted considerable attention. ZNA (Z Network Architecture) is one of clean-slate network architectures based on the layered model. The major features of ZNA are as follows: (1) introducing the session layer to provide the applications with sophisticated communication services, (2) employing inter-node cross-layer cooperation to adapt to the dynamically changing network conditions, (3) splitting the node identifier and the node locator for mobility, multi-homing, and heterogeneity of network layer protocols, (4) splitting the data plane and the control plane for high manageability, and (5) introducing a recursive layered model to support network virtualization. This paper focuses on the first three topics as well as the basic design of ZNA.

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広域分散サーバを用いた大容量ファイルの保存・取得方式

安藤大佑, 寺岡文男, 金子晋丈

電子情報通信学会論文誌（一般社団法人電子情報通信学会） J97-B （ 10 ） 861 - 872 2014年10月

研究論文（学術雑誌）, 共著, 最終著者, 査読有り

コンピュータ技術・ネットワーク技術の発展に伴い大容量コンテンツを利用する機会が増加している．しかしながら，大容量コンテンツをインターネットを介して高速かつ低ストレージコストで共有・保存することは難しい．筆者らは大容量コンテンツを対象として広域分散ストレージサーバに分散保存し，高速かつ低ストレージコストでインターネット規模のコンテンツ共有と可用性・信頼性のあるコンテンツ保存を実現するContent Espressoの設計と実装をしている．本論文では，Content Espressoの技術的要となるファイル保存・取得方式について述べる．本方式はネットワーク状態によらずファイル取得時間を予測でき，保存ファイルの信頼性・可用性を低冗長率で保証するファイル保存・取得方式である．本方式のアプローチは，1)前方誤り訂正(FEC: Forward Error Correction)符号を利用したファイル冗長化，2)データをチャンクに分割し，世界中のストレージサーバへ分散保存，3) UDPを利用したデータ取得の3点である．このアプローチに沿って本方式を設計・実装し，インターネット規模ネットワーク環境を想定した評価により，TCPを利用したファイル転送方式よりも，ファイル取得時間予想が容易であることを確認した．

Impacts of periodical burst packet loss on streaming applications - Focusing on a mobile network in a high-speed train

Terada M., Kaneko K., Teraoka F.

Proc. of the 28th International Conference on Advanced Information Networking and Applications Workshops （IEEE） 504 - 511 2014年05月

研究論文（国際会議プロシーディングス）, 共著, 査読有り

This paper investigates impacts of periodical burst packet loss on three typical streaming applications: YouTube, Internet Radio, and Skype, supposing a mobile network in a high-speed train. Although the characteristics of YouTube and Skype are well analyzed, the characteristics of Internet Radio and the characteristics of these applications under periodical burst packet loss have not been analyzed. First, this paper analyses how much these applications are tolerant to periodical burst packet loss. Second, this paper analyses correlation between application layer protocols and transport layer protocols. As a result, some correlations between transport layer protocols and application layer protocols were found. For example, in YouTube, if TCP segment retransmissions frequently occur before starting content download, a client tries to download the entire content with a single HTTP request while a client repeatedly downloads a chunk of the content with multiple HTTP requests under ordinary network condition. © 2014 IEEE.

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Impact of multiple home agents placement in mobile IPv6 environment

Erunika O., Kaneko K., Teraoka F.

IEICE Transactions on Communications （IEICE） E97-B （ 5 ） 967 - 980 2014年05月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 0916-8516

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Fast handover mechanism for high data rate ground-to-train free-space optical communication system

Mori K., Terada M., Nakamura K., Murakami R., Kaneko K., Teraoka F., Yamaguchi D., Haruyama S.

Proc. of 2014 IEEE Globecom Workshops (GC Wkshps) （IEEE） 499 - 504 2014年03月

研究論文（国際会議プロシーディングス）, 査読有り

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ヤマタノオロチ:インターネットサービスのための認証認可基盤

厚谷有輝, 金子晋丈, 寺岡文男

情報処理学会論文誌（一般社団法人情報処理学会） 55 （ 2 ） 849 - 864 2014年02月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 1882-7764

本論文はインターネットを通して提供される様々なサービスに対し，統一的な認証認可の仕組みを実現する汎用認証認可基盤ヤマタノオロチを提案する．汎用の認証認可基盤には“マルチドメイン環境で多様な認証方式をサポートすること”，“サービスによらないアクセス制御を実現すること”，“基盤の負荷を少なくしてスケーラビリティを確保すること”の3つが要求事項としてあげられる．本論文で提案するヤマタノオロチはこれらの要求事項を満たすような認証と認可の機能を提供するシステムである．AAAプロトコルのDiameterと認証フレームワークのEAPを利用することで，ユーザ情報の一元化とマルチドメイン認証を可能とした．またKerberosやXACMLを参考にしたチケットシステムを設計し，サービスによらないアクセス制御とスケーラビリティの確保を実現した．これらの設計に基づいて実装したシステムが複数のインターネットサービスにおいて正しく動作することを検証し，認証および認可の処理時間も実用上問題ない時間で処理が完了することも確認した．

Content espresso: A system for large file sharing using globally dispersed storage

Ando D., Kitamura M., Teraoka F., Kaneko K.

Proc. of the 5th International Conference on Cloud Computing Technology and Science (CloudCom2013) （IEEE） 2 337 - 340 2013年12月

研究論文（国際会議プロシーディングス）, 共著, 最終著者, 査読有り, ISSN 23302194

Sharing files over the world with higher access throughput and with lower storage cost is a growing demand for the applications that use large files. However, the existing file sharing systems do not realize these two conflicted requests and no research has been found. This paper clarifies the requirements of a global large file sharing system and defines the design goal consisting of three users perspectives: fast retrieving, user defined file availability, and owner-based file management, and one system operators perspective: flexibility in bytes placement. Content Espresso satisfies this goal by approaching with four techniques: three sections model, distributed chunk storage, forward error correction, and UDP retrieving. Content Espresso delivers large files to a client utilizing as much bandwidth as the client access link even servers are located far away from the client. © 2013 IEEE.

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Multiple home agent placement considerations based on internet service provider perspective in MobileIPv6

Dayaratna H.R.O.E., Kaneko K., Teraoka F.

Proc. of the 37th Annual Computer Software and Applications Conference (COMPSAC2013) （IEEE） 471 - 474 2013年07月

研究論文（国際会議プロシーディングス）, 共著, 査読有り, ISSN 07303157

To overcome MobileIPv6's natural centrality driven single point of failure and redundant routing due to central Home Agent in home network, Global HAHA introduced an overlay of scattered multiple HAs. Placements of secondary HAs were not addressed by major work in existence. This paper analyses placements in ISP's viewpoint at AS level. Freeman's closeness index and betweenness are used in categorizing examined AS level topology of 30, 000 nodes. 30, 000 different random communications were analyzed which substantiated that Freeman's closeness describes topological locations better. Results show that categories having highest, medium indices are tend to hold better performance only when combined with an HA of lowest category. Lowest category shows best performance with the highest category. © 2013 IEEE.

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CLINEX: An inter-node cross-layer cooperation architecture to adapt to dynamically changing network situation

Yonemura K., Kaneko K., Teraoka F.

Proc. of the 37th Annual Computer Software and Applications Conference (COMPSAC 2013) （IEEE） 33 - 42 2013年07月

研究論文（国際会議プロシーディングス）, 共著, 査読有り, ISSN 07303157

To efficiently adapt to dynamically changing network environment such handover and link failure, cross-layer cooperation mechanisms are indispensable. This paper first introduces the following five requirements to cross-layer cooperation architecture through a discussion, (1) cooperation between a layer in a node and a layer (not necessary the same layer) in another node, (2) abstraction of control information, (3) definition of primitives in each layer, (4) availability in a wide area network, and (5) implementation. Although there are a lot of proposals of cross-layer cooperation architecture in the literature, none of them satisfy the five requirements. This paper designs an inter-node cross-layer cooperation architecture called CLINEX (Cross-Layer and Inter-Node information EXchange) so that it satisfies the five requirements. CLINEX is implemented in the user space and the kernel space of Linux. Two scenarios are tested in our test network composed of eight machines. One scenario is congestion detection at a remote node, which results in sending rate control at the end node. Another scenario is link failure detection at a remote node, which results in failover in an SCTP association. The measurement results show that the processing time of CLINEX is negligible in comparison with packet transmission latency. © 2013 IEEE.

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Validation of session layer protocols and API in ZNA

Ide M., Kaneko K., Teraoka F.

Proc. of the 8th Asian Internet Engineering Conference (AINTEC 2012) （Association for Computing Machinery） 77 - 84 2012年12月

研究論文（国際会議プロシーディングス）, 共著, 査読有り

The AKARI Project, one of clean slate approaches to design New Generation Network (NwGN), is proposing a six-layer network architecture called ZNA (Z Network Architecture). One of the features of ZNA is that the session layer (L5) is inserted between the application layer (L6) and the transport layer (L4) to provide the application layer with more sophisticated communication paths. The API and protocols of L5 have been proposed, however the behavior has not been confirmed by implementation. This paper designs in detail the protocols and APIs of L5, and verifies the feasibility by implementing a prototype of L5 in the user space before implementing it in the kernel. In this prototype, two new types of paths can be established: the bundled path and the spatiallyspliced path. In the former, bandwidth aggregation or fault tolerance is supported by using multiple L4 paths. In the latter, end-to-end communication via middle boxes is supported by splicing two L4 paths at the middle boxes after negotiation between the end node and the middle boxes. Copyright 2012 ACM.

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Content Espresso: A global secure large file sharing system for media industries

Kaneko K., Ando D., Teraoka F.

Proc. of the 13th ACIS International Conference on Software Engineering, Artificial Intelligence, Networking and Parallel/Distributed Computing (SNPD 2012) （IEEE） 649 - 654 2012年08月

研究論文（国際会議プロシーディングス）, 共著, 筆頭著者, 責任著者, 査読有り

Recently, it becomes common to handle large files in computers. However, we have a difficulty to realize file sharing over networks, especially for large files. The problem is that we have extended the system model designed decades ago based on a stand-alone computer model. Assuming that all files are located in data centers, and nobody accesses them at the sites, we can redesign the file sharing system model for higher access speed and efficient storage resource usage. We designed a global secure file sharing system called Content Espresso. In this paper, we describe the difficulty, the design goal for global secure file sharing system, and our approach for it. Finally, we explain the impact of Content Espresso on network. © 2012 IEEE.

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Design and implementation of live image file feeding to dome theaters

Kaneko K., Ohta N.

Future Generation Computer Systems （Elsevier Science Publishers B. V.） 27 （ 7 ） 944 - 951 2011年07月

研究論文（学術雑誌）, 共著, 筆頭著者, 責任著者, 査読有り, ISSN 0167739X

This paper proposes a live transmission system to dome theaters with multiple-projector projection systems. Our live transmission to dome theaters solves three issues between the sender and the receiver: slicing, image size, and clock synchronization. These issues make it difficult to apply a conventional streaming approach to dome theaters. We propose a file-based approach, which we call live image file feeding. We realize live file transfer by checking the file status periodically, transmitting reliably at a constant bit rate, and retransmitting immediately if packets are lost. We implemented this system, named it the Kaneko file system (KFS), and evaluated its functionality. Furthermore, we tested the entire live transmission system using the KFS, a digital still camera and a dome theater during the total solar eclipse in 2009 and showed that it worked well with 3K×3K image pixels. © 2010 Elsevier B.V. All rights reserved.

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Multi-point 4K/2K layered video streaming for remote collaboration

Shirai D., Kitamura M., Fujii T., Takahara A., Kaneko K., Ohta N.

Future Generation Computer Systems （Elsevier Science Publishers B. V.） 27 （ 7 ） 986 - 990 2011年07月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 0167739X

The progress of technologies in image industries and the rapid spread of broadband networks allow us to put high quality video communications to use for remote collaboration. We have developed a 4K/2K layered video streaming system with JPEG 2000 codec. It offers three main advances; support of various video formats to realize a media exchange platform, 4K/2K layered streaming with multicast to utilize 4K images even if the environment has no 4K equipment, and robust transmission using a forward error correction (FEC) scheme that can deal with bandwidths beyond 800 Mbit/s. Using the system, we conducted the world's first multi-point ''shared collaborative space'' experiment with a large audience in CineGrid International Workshop 2008. It proved the feasibility of the new environment for 4K remote collaboration between multiple points including those that did not have 4K equipment. This paper details the system and implemented technologies.

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Tri-continental premiere of 4K feature movie via network streaming at FILE 2009

Margolis T., Brown S., Cornish T., Bracho H., Stanton M., Melo De Brito Carvalho T.C., Redigolo F.F., De Castro F.C., Kaneko K., De Almeida J., Da Silva C.I., De Souza E.A.

Future Generation Computer Systems （Elsevier Science Publishers B. V.） 27 （ 7 ） 924 - 934 2011年07月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 0167739X

The aesthetic potentials of 4K digital cinema are an impetus for creative practitioners of cinematic arts to undertake full investigations of the methods and expressive possibilities of this end-to-end digital medium. This includes new approaches to production, distribution and the forum of theatrical experience. A group of artists, film-makers and computer scientists have been developing a series of 4K digital cinema projects that have diffused and grown the manner in which 4K cinema is experienced between Brazil, the US and Japan. The recent culmination of this was an event in July 2009 in which a 4K feature length movie had its world premiere on three continents, streamed from Brazil to the US and Japan. This was accompanied by an HD video teleconference (VTC) between the three sites. To the knowledge of the participants, this was both the first uncompressed HD VTC between the northern and southern hemispheres as well as the first feature length 4K film to be streamed across three continents. Through this work, the new creative affordances of 4K cinema were highlighted, along with the new capabilities of cinematic distribution, production and experience.

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Beyond 4K: 8K 60p live video streaming to multiple sites

Kitamura M., Shirai D., Kaneko K., Murooka T., Sawabe T., Fujii T., Takahara A.

Future Generation Computer Systems （Elsevier Science Publishers B. V.） 27 （ 7 ） 952 - 959 2011年07月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 0167739X

The high definition of 4K motion pictures makes them applicable to a wide variety of purposes. The development of 4K image equipment such as cameras, displays, and playback systems has made easy viewing of 4K video possible. Video frame rates have also become higher, enabling 4K-60 fps progressive (60p) video streams to be transmitted over IP networks. However, problems remain in increasing video image resolution to 8K or more so as to build systems in which many people collaborate at the same time. This paper describes a video transmission system that attains image resolution of 8K-60p or higher by synchronizing multiple 4K transmission systems we have developed. Since 8K-60p transmission over IP networks has extremely high traffic rates, schemes for achieving robust transmission such as forward error correction (FEC) must also have very high rates. We have also developed techniques for attaining reliable transmission, i.e., the use of low-density generator matrix (LDGM) codes to achieve high throughput FEC, application-layer multicasting, and monitoring network status at multiple points.

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Precise network monitoring for high quality live streaming

Kaneko K.

Proc. of the 3rd International Conference on Ubiquitous and Future Networks (ICUFN2011) （IEEE） 83 - 88 2011年06月

研究論文（国際会議プロシーディングス）, 単著, 筆頭著者, 最終著者, 責任著者, 査読有り, ISSN 2165-8528

Live streaming of high quality media requires high quality network in terms of packet loss rate and jitter. However, the current IP or Ethernet network does not assure the bandwidth or jitter for streaming in general. In addition, the existing network monitoring system does not have the functionality to measure these network quality. My precise network monitoring is a packet-by-packet network monitoring to observe switching or routing latency inside of a switch, router, or network, and provide the statistics of a flow that is specified by user on-demand. We implemented this system, installed it in the existing network, and evaluated its functionality. It shows the impact of cross-traffic on a measured flow. © 2011 IEEE.

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4K applications beyond digital cinema

Kaneko K., Ohta N.

Proc. of the 16th International Conference on Virtual Systems and Multimedia (VSMM2010) （IEEE） 133 - 136 2010年10月

研究論文（国際会議プロシーディングス）, 共著, 筆頭著者, 責任著者, 査読有り

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Field trial of 80 (10 x 8λ) Gbps colored optical packet switching of 4K&2K uncompressed streaming

Kataoka N., Shimizu K., Kawano T., Kaneko K., Sone K., Maruyama M., Ishikawa G., Awaji Y., Otsuki H., Aoyama T., Kinoshita S., Wada N., Kitayama K.

Proc. of European Conference on Optical Communication (ECOC 2010) （IEEE） 1-2 1 - 3 2010年09月

研究論文（国際会議プロシーディングス）, 共著, 査読有り, ISSN 1550-381X

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3K x 3K Live Total Solar Eclipse Transmission

Kaneko K., Nishimura H., Takahashi R., Ohta N.

Proc. of the 20th International Planetarium Society Conference (IPS 2010) （The Bibliotheca Alexandrina & the International Planetarium Society） 29 - 34 2010年06月

研究論文（国際会議プロシーディングス）, 共著, 筆頭著者, 責任著者, 査読有り

Digital projection systems are now becoming popular in planetariums. One of the biggest advantages of the digital projection system is live viewing capability that enables audiences in planetariums to see phenomena observed at remote locations. Although several trials of live viewing in a planetarium have been carried out, a live viewing system has not yet been standardized and it is still a challenge to realize higher image quality in large digital domed theaters by multiple projectors. In this paper, we describe our live viewing system consisting of acquisition by digital cameras, transmission through networks, pre-processing for projection, and projection in domed theaters. In addition, we introduce our live viewing trial of the total solar eclipse from three locations in Asia to a digital domed theater in Sendai, Japan in 2009. In the trial, we accomplished 0.5 frame/second live viewing of nine million pixels images by two 4K x 2K projectors in a 250 seat 25m domed theater.

A LIVE image transmission system for dome theaters

Kaneko K., Ohta N.

Proc. of the 8th Asia-Pacific Symposium on Information and Telecommunication Technologies (APSITT2010) （IEEE） 1 - 6 2010年06月

研究論文（国際会議プロシーディングス）, 共著, 筆頭著者, 責任著者, 査読有り

Digital projection is increasingly being deployed to dome theaters that have been mainly used for planetarium. Compared with traditional film projection, digital projection has a flexibility of content. Especially, LIVE presentations are the most unique contents using digital feature. On the other hand, in order to show by digital, we have to prepare high quality digital contents. In planetarium community, it is said that 64 million pixel counts are the ideal, 16 million pixels are the adequate, and 4 million pixels are the minimum even for ten meters small domes. If domes are larger, we need more. In this paper, we focus on LIVE transmission system for digital domes. LIVE dome contents are basically created by the following three steps like other digital LIVE contents; capturing, transmission, and projection. The notable differences are that the image must be captured with big pixels using circle fish eye lens to be qualified for domes, large size data transmission to avoid image quality degradation, and it has to be spatially divided for multi-projector projection keeping its quality. Especially for LIVE system, we have to make sure that each process must be realized in real time. We've developed a LIVE transmission system that consists of existing digital still camera, a newly designed LIVE image sharing tool, and existing digital dome presentation system. It realizes 0.5 frame/second LIVE transmission of 9 million pixels image. We transmitted total solar eclipse from three locations in Asia to a dome in Japan in July 2009 using this system.

4K transmission experiments at Keio DMC

Kaneko K., Ohta N.

Proc. of International Symposium for Immersive Science Visualization （2010 the Organizing Committee for Prparatory Event 2009 and National Astronomical Observatory） 93 - 96 2009年03月

研究論文（国際会議プロシーディングス）, 共著, 筆頭著者, 責任著者, 査読有り

We, Keio DMC, have tried several experiments related to 4K networking applications. In this paper, we briefly explain what 4K is and why 4K requires networking. Then, we introduce our three experiments based on the expected applications. One is 4K network distribution, one is 4K networked production, and the other is 4K videoconference. These experiments were tested over International communication networks and showed not only its concepts but also its feasibility. Finally, we discuss the similarity between 4K and dome theater applications. Dome theater presentations also need a quite big image size due to the huge screen size. Sometimes, it is eight times bigger than 4K. The networking technology developed for 4K can be used for easy content production. On the other hand, dome theaters are at the turning point to change their systems to digital from the point of business. It opens up new services called alternative content like live broadcasting of natural phenomena using network.

4K Uncompressed Streaming over Multicast-Capable 80 (8λx10) Gbps Colored Optical Packet Switching Network Using SOA Switch and Stacked OC-Label Processing

Kataoka N., Sone K., Kaneko K., Aoyama T., Shimizu K., Kawano T.

Proc. of the Optical Fiber Communication Conference and The National Fiber Optic Engineers Conference (OFC/NFOEC 2009) （IEEE） 1 - 3 2009年03月

研究論文（国際会議プロシーディングス）, 共著, 査読有り

Real time switching and streaming transmission of uncompressed 4K motion pictures

Shirai D., Kawano T., Fujii T., Kaneko K., Ohta N., Ono S., Arai S., Ogoshi T.

Future Generation Computer Systems （Elsevier Science Publishers B. V.） 25 （ 2 ） 192 - 197 2009年02月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 0167739X

In this paper we describe the world's first Trans-Pacific and Trans-Atlantic real-time switching and streaming transmission of uncompressed 4K motion pictures. This demonstration, of an advanced networked media application, conveyed the 23rd Kyoto Prize events, held on Nov. 10 and 11, 2007, from Kyoto, Japan to Stockholm, Sweden in real-time with life-like image quality. Multiple live 4K streams from different cameras were switched over the network into a single uncompressed stream at the director's request, and transmitted to Stockholm via 10 Gbit Ethernet connections over 21,000 km using the Global Lambda Integrated Facility (GLIF). We introduce several new technologies, including an uncompressed 4K video streaming system using Internet Protocol (IP) transmission and a shared line approach to gap-less video switching control. The Kyoto Prize 2007 demonstration proves the feasibility of using the IP infrastructure for next generation video switching and distribution networks, even at very high speeds across great distances.

Access to Document (DOI)

プリアンブル遅延によるラベル更新処理を用いた自己ルーチング型光パケット転送機構

松本延孝, 金子晋丈, 今泉英明, 森川博之, 青山友紀

電子情報通信学会論文誌 B （一般社団法人電子情報通信学会） J91-B （ 10 ） 1244 - 1253 2008年10月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 1344-4697

本論文では，自己ルーチングを用いた光パケット転送ネットワークにおいて，ヘッダ長のオーバヘッドを抑えるためのプリアンブル遅延型ラベル更新手法を提案し，その効果を評価する．大容量の光伝送技術を生かした光パケット技術は，光RAMや光論理回路などの光デバイスの欠如からIPヘッダ処理のような複雑な機能を用いて実現することが困難である．これに対して，ヘッダ内に通過する経路上の中継ノード情報をすべて記述することで，中継ノードにおける転送処理を単純化する自己ルーチングの適用が研究されている．しかし既存手法では，任意トポロジーのネットワークにおいてヘッダ長がペイロード長に対して長くなり，帯域利用効率が低下する問題があった．本論文で提案するプリアンブル遅延型ラベル更新手法では，ヘッダの先頭を識別するプリアンブルを転送処理時の読取りデータ長分遅延させることで，光領域でのラベル更新を実現し，短いヘッダ書式の適用を可能とする．シミュレーション結果より，特にネットワーク規模が大きくなる場合に，既存手法に比べてヘッダ長を短く抑えられることが示された．

ユーザ主導型通信制御のためのセッション層構成に関する研究

金子晋丈

東京大学 2006年03月

学位論文（博士）, 筆頭著者, 最終著者, 責任著者

Personal Mesh: A Design of Flexible Internet Access for Personal Area Network

Hoaison N., Shindo A., Kaneko K., Morikawa H., Aoyama T.

Proc. of the 6th International Symposium on Wireless Personal Multimedia Communications (WPMC 2003) 3 256 - 260 2003年10月

研究論文（国際会議プロシーディングス）, 共著, 査読有り

Session Layer Mobility Support for 3C Everywhere Environments

Kaneko K., Morikawa H., Aoyama T.

Proc. of the 6th International Symposium on Wireless Personal Multimedia Communications (WPMC 2003) 2 347 - 351 2003年10月

研究論文（国際会議プロシーディングス）, 共著, 筆頭著者, 責任著者, 査読有り

Secure Session Migration Using Key-Insulated Public-Key Cryptosystems

Lim S., Kaneko K., Morikawa H., Aoyama T.

Proc. of the 1st Joint Workshop on Mobile Multimedia Communications (JWMMC2003) 57 - 61 2003年07月

研究論文（国際会議プロシーディングス）, 共著, 査読有り

On-demand Data Prefetching System for Spotted Access Networks

Imai N., Kaneko K., Morikawa H., Aoyama T.

Proc. of the 7th Asia Pacific Conference on Communications (APCC2001) （Institute of Electronics, Information and Communication Engineers） 61 - 64 2001年09月

研究論文（国際会議プロシーディングス）, 共著, 査読有り

In future, spotted access networks will enable users to handle large files. We will be able to download movie and enjoy it at any time. However, the narrow and discontinuous areas will result in throughput decrease for the users moving with high speed (e.g. in a car). To avoid the problem, we show on-demand data prefetching system in which users preserve the files via any access networks before they enters into the spotted network area. The requested files are prefetched in Spool Server located in spotted network so that they can start receiving data as soon as possible. We also show our testbed networks and experimental results.

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