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International Workshop on Acoustic Signal Enhancement (IWAENC)

作者： Shihori Kozuka Shoichi Koyama Hiroaki Itou Noriyoshi Kamado NTT Computer and Data Science Laboratories NTT Corporation Japan Digital Content and Media Sciences Research Division National Institute of Informatics Japan

ISBN: (数字)9798350361858

ISBN: (纸本)9798350361865

A method for estimating the incident sound field in a region containing scattering objects is extensively evaluated for various scatterers. Estimating a sound field using multiple microphones has a wide variety of applications, e.g., spatial audio capturing and spatial active noise control. Most current methods do not allow the inclusion of any scattering objects or allow only the inclusion of scattering objects of known properties. An incident sound field estimation method in a region including scattering objects of unknown properties has recently been proposed, which has high practical potential in the above-mentioned applications. However, its experimental evaluation is limited to a simple rigid spherical object even though various types of scatterers can be present in practical situations. We evaluate the incident sound field estimation method for various types of scatters in numerical simulations using the boundary element method. Experimental results indicated that the appropriate design of the weighting matrix for expansion coefficients can further improve the estimation accuracy.

关键词： Shape Conferences Spatial audio Noise Scattering Estimation Numerical simulation Wave functions Kernel Microphones

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Stimulated emission from superradiant atoms in waveguide QED

Stimulated emission from superradiant atoms in waveguide QED

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CLEO: science and Innovations, S and I 2022

作者： Asaoka, Rui Gea-Banacloche, Julio Tokunaga, Yuuki Koshino, Kazuki Computer and Data Science Laboratories NTT Corporation Musashino180-8585 Japan Department of Physics University of Arkansas FayettevilleAR72701 United States College of Liberal Arts and Sciences Tokyo Medical and Dental University Ichikawa272-0827 Japan

We investigate the stimulated emission from superradiant atoms coupled to a waveguide induced by a coherent-state pulse. We provide the dynamical properties of this system and also evaluate the system as a amplifier. ... 详细信息

ISBN: (纸本)9781557528209

关键词： Stimulated emission

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Griffin: Fast Transactional database Index with Hash and B+-Tree

Griffin: Fast Transactional Database Index with Hash and B+-...

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IEEE International Conference on e-science and Grid Computing

作者： Sho Nakazono Yutaro Bessho Hideyuki Kawashima Tatsuhiro Nakamori Computer and Data Science Laboratories NTT Tokyo Japan Faculty of Environment and Information Studies Keio University Kanagawa Japan

ISBN: (数字)9798350365610

ISBN: (纸本)9798350365627

Index access is one of the dominant performance factors in transactional database systems. Many systems use a B+tree or one of its variants to handle point and range operations. This access pattern has room for performance improvement. Firstly, point operations can potentially be processed in O(1) with a hash table. Secondly, to ensure serializability of transactions, range operations incur overhead from phantom avoidance techniques that involve additional processing or synchronization, such as an extra traversal of the B+-tree. To address these issues, we propose a hybrid index architecture, Griffin. For point operations, Griffin has a hash table that provides access paths in O(1) time, along with a B+-tree. For phantom avoidance, Griffin employs a precision locking method, which does not involve additional traversal of the B+-tree. Despite its hybrid architecture, Griffin transparently provides linearizable operations and an interface of a single database index. We built a Griffin index combining a hash table and BwTree. Compared to a baseline index that is composed of a BwTree only, it achieves up to 3.1x higher throughput in a point operation dominant workload, and up to 5.4x higher throughput in a range operation dominant workload.

关键词： Phantoms Throughput data structures Indexes Synchronization Periodic structures

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Fast Hybrid Transactional Index with Scalable Phantom Avoidance

Fast Hybrid Transactional Index with Scalable Phantom Avoida...

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International Symposium on Computing and Networking Workshops (CANDARW)

作者： Yutaro Bessho Hideyuki Kawashima Computer and Data Science Laboratories NTT Tokyo Japan Faculty of Environment and Information Studies Keio University Fujisawa Japan

ISBN: (数字)9798331505349

ISBN: (纸本)9798331505356

Griffin is a hybrid transactional index structure that combines a hash table and B+-tree. The key benefit of Griffin is that it processes single-key operations fast using the hash table. For serializable transactions, Griffin avoids phantoms with precision locking, a technique that protects updates and predicate reads with a lock. Although Griffin performs well under infrequent updates, under update-heavy workloads, the lists of locks kept by precision locking significantly grow in size, causing severe performance degradation. We identify this is because locks are released by only one thread called sync manager, which is also responsible for the heavy task of synchronizing the hash table and B+-tree. As a result, sync manager often fails to release locks as fast as they are acquired, causing the lock lists to grow. We propose a new design for Griffin, Griffin-PPL (Parallel Precision Locking), which prevents the lock lists from growing. Griffin-PPL removes sync manager, the bottlenecking thread, and parallelizes the work of releasing locks and synchronization among all transaction worker threads. To allow for parallelization, we adopt a decentralized data structure for the lock lists. Our evaluation in a microbenchmark shows that under an update-heavy workload (50% inserts, 50% scans), Griffin-PPL exhibits a throughput 6.5x the conventional Griffin architecture, at 64 threads.

关键词： Degradation databases Conferences Phantoms Parallel processing data structures Throughput Synchronization Indexes

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Towards Log-based Execution Status Estimation Using Graph Neural Networks

Towards Log-based Execution Status Estimation Using Graph Ne...

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Asia-Pacific Conference on Software Engineering

作者： Shimon Sumita Hiroyuki Nakagawa Shinobu Saito Tatsuhiro Tsuchiya Osaka University Osaka Japan Okayama University Okayama Japan NTT Computer and Data Science Laboratories Tokyo Japan

ISBN: (数字)9798331534011

ISBN: (纸本)9798331534028

This study addresses software bloat, a prevalent issue in modern software development, causing excessive size and complexity due to feature additions and unnecessary functions. Such bloat leads to decreased efficiency, performance degradation, and increased vulnerability. To combat this issue, the concept of software 3R (reduce, reuse, recycle) is proposed; however, accurately reproducing the internal state of black-box software for 3R requires both source code and execution log data, posing practical challenges. In this paper, we conduct a software execution status estimation using limited execution log. Graph Neural Networks (GNNs) are employed for analysis, offering effective processing of graph data. The task is framed as link prediction and node classification, comparing traditional deep learning methods with GNNs using Apache OFBiz ERP software logs. Preliminary results validate GNN applicability.

关键词： Degradation Deep learning Source coding Estimation Closed box Graph neural networks Recycling Complexity theory Software engineering Software development management

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Griffin: Fast Transactional database Index with Hash and B+-Tree

arXiv

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arXiv 2024年

作者： Nakazono, Sho Bessho, Yutaro Kawashima, Hideyuki Nakamori, Tatsuhiro Computer and Data Science Laboratories NTT Tokyo Japan Faculty of Environment and Information Studies Keio University Kanagawa Japan

关键词： database systems

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Type-Based Verification of Connectivity Constraints in Lattice Surgery

arXiv

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arXiv 2024年

作者： Wakizaka, Ryo Suzuki, Yasunari Igarashi, Atsushi Graduate School of Informatics Kyoto University Japan NTT Computer and Data Science Laboratories Musashino180-8585 Japan

Fault-tolerant quantum computation using lattice surgery can be abstracted as operations on graphs, wherein each logical qubit corresponds to a vertex of the graph, and multi-qubit measurements are accomplished by connecting the vertices with paths between them. Operations attempting to connect vertices without a valid path will result in abnormal termination. As the permissible paths may evolve during execution, it is necessary to statically verify that the execution of a quantum program can be completed. This paper introduces a type-based method to statically verify that well-typed programs can be executed without encountering halts induced by surgery operations. Alongside, we present QLS, a first-order quantum programming language to formalize the execution model of surgery operations. Furthermore, we provide a type checking algorithm by reducing the type checking problem to the offline dynamic connectivity problem. © 2024, CC BY.

关键词： Qubits

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Circuit designs for practical-scale fault-tolerant quantum computing

Circuit designs for practical-scale fault-tolerant quantum c...

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2023 IEEE Symposium on VLSI Technology and Circuits, VLSI Technology and Circuits 2023

作者： Suzuki, Yasunari Ueno, Yosuke Liao, Wang Tanaka, Masamitsu Tanimoto, Teruo Ntt Computer & Data Science Laboratories Tokyo Musashino Japan Jst Resto Kawaguchi Saitama Japan Keio University Kanagawa Yokohama Japan The University of Tokyo Bunkyo-ku Tokyo Japan Nagoya University Aichi Nagoya Japan Kyushu University Fukuoka Japan

ISBN: (纸本)9784863488069

To demonstrate reliable and scalable quantum computation, we need quantum error correction to reduce its error rates. One of the most challenging parts of implementing quantum error correction is to design error-decoding units, which estimate errors during computation. We estimate the required performances of error-decoding units to run practical-scale quantum algorithms and discuss the directions to satisfy them. © 2023 JSAP.

关键词： Quantum computers

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Finding Contributable Activities Using Non-Verb Attributes In Events 27

Finding Contributable Activities Using Non-Verb Attributes I...

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27th International Conference on Knowledge Based and Intelligent Information and Engineering Sytems, KES 2023

作者： Kaiya, Haruhiko Takeuchi, Hironori Nakagawa, Hiroyuki Ogata, Shinpei Saito, Shinobu Kanagawa University Yokohama221-8686 Japan Musashi University Tokyo176-8534 Japan Osaka University Osaka565-0871 Japan Shinshu University Nagano380-8553 Japan NTT Computer and Data Science Laboratories Tokyo108-0023 Japan

Many different activities are performed simultaneously in the real world, and one of them contains actions, that can be utilized in another activity. If such actions are actually utilized, the activity utilizing them become more efficiently than ever. We call the activity providing such actions a contributable activity, and the one utilizing the actions a contributed activity. Our research goal is to find such contribution relationships between activities. To achieve the goal, we used a conformance checking technique in the field of process mining research. In the process mining research, logs of actions and control flow models are used, and the logs and the models are usually represented by the verb attribute in an action such as "submit", "decide" and so on. However, we could not find some contribution relationships by using the logs and models of the verb attribute. We thus examine the usage of non-verb attributes such as a place or a tool in an action for our goal. Through a case study about elderly people care, we find non-verb attributes have some potential to achieve our goal more comprehensively than ever. © 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://***/licenses/by-nc-nd/4.0)

关键词： Conformance checking Non-verb attributes in a log Process mining

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A Proposal to Find Mutually Contributable Business or Life Activities Using Conformance Checking 26

A Proposal to Find Mutually Contributable Business or Life A...

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26th International Conference on Knowledge-Based and Intelligent Information and Engineering Systems, KES 2022

作者： Kaiya, Haruhiko Misawa, Tomoya Ogata, Shinpei Saito, Shinobu Nakagawa, Hiroyuki Takeuchi, Hironori Kanagawa University Hiratsuka259-1293 Japan Shinshu University Nagano380-8553 Japan NTT Computer and Data Science Laboratories Tokyo108-0023 Japan Osaka University Suita565-0871 Japan Musashi University Tokyo176-8534 Japan

We propose a method to comprehensively find a pair of business or life activities, which can mutually contribute to each other. We assume that the activities with synchronized processes can mutually contribute to each other. A process model of an activity is thus compared to a log of another activity for measuring whether the activities can synchronize their processes to a certain extent using a conformance checking technique. The threshold of the extent is defined on the basis of a randomly generated log containing the same events as those in the compared log. We tentatively evaluated the method through a case study, and confirmed that the method seemed to be valid. © 2022 The Authors. Published by Elsevier B.V.

关键词： Conformance checking Cross-organizational process Process mining Sharing process

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