担当区分：最終著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

In Cyber-Physical Systems (CPS), numerous devices gather sensor data into the cyber domain, which is then consumed by various services, such as robots and analytic services, in a dynamic and real-time manner. The Publish-Subscribe (Pub/Sub) model is a promising communication paradigm that can easily support many-to-many data sharing. By introducing the intermediate message broker responsible for message forwarding, Pub/Sub can decouple the message publisher and its subscribers and achieve scalable data sharing. However, ensuring the confidentiality of messages against the broker presents a key challenge when distributing private information over Pub/Sub. End-to-end encrypted (E2EE) Pub/Sub protocol is a promising approach to support message confidentiality in Pub/Sub. Within CPS, sensor data is dynamically consumed by multiple services, and thus E2EE Pub/Sub should support dynamic changes in subscribers in a scalable manner. However, existing protocols have scalability issues due to the excessive number of messages on the order of N² for N subscribers during key updates. This paper presents a new E2EE Pub/Sub protocol designed to support dynamic data sharing in CPS, inspired by the state-of-the-art secure group messaging protocol, Messaging Layer Security (MLS). By carefully integrating MLS features into Pub/Sub, our protocol effectively handles dynamic subscriber changes in a scalable manner, updating keys with only (ON)messages.

DOI： 10.23919/IFIPNetworking62109.2024.10619724

Scopus

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Satellite computing has emerged as a promising technology for next-generation wireless networks. This innovative technology provides data processing capabilities, which facilitates the widespread implementation of artificial intelligence (AI)-based applications, especially for image processing tasks involving deep neural network (DNN). With the limited computing resources of an individual satellite, independently handling DNN tasks generated by diverse user equipments (UEs) becomes a significant challenge. One viable solution is dividing a DNN task into multiple subtasks and subsequently distributing them across multiple satellites for collaborative computing. However, it is challenging to partition DNN appropriately and allocate subtasks into suitable satellites while ensuring load balancing. To this end, we propose a collaborative satellite computing system designed to improve task processing efficiency in satellite networks. Based on this system, a workload-balanced adaptive task splitting scheme is developed to equitably distribute the workload of DNN slices for collaborative inference, consequently enhancing the utilization of satellite computing resources. Additionally, a self-adaptive task offloading scheme based on a genetic algorithm (GA) is introduced to determine optimal offloading decisions within dynamic network environments. The numerical results illustrate that our proposal can outperform comparable methods in terms of task completion rate, delay, and resource utilization.

DOI： 10.1109/ISCC61673.2024.10733633

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記述言語：英語   掲載種別：研究論文（学術雑誌）

Cyber Physical System (CPS) and Internet of Things (IoT) have attracted attention as a promising technology for the future society. Although the 6th generation mobile system is expected to work as the CPS/IoT platform, the specific technical requirements are not studied thoroughly. In this paper, we take application driven approach focusing on three applications, eHealth, smart manufacturing, and smart city, to identify mandatory technical requirements for the 6G mobile core network architecture to realize CPS/IoT systems. Specifically, this paper gives the following three contributions. First, we investigate several use cases in the applications listed above and list up the requirements for the core network, i.e., the massive connectivity, the flexible SLA, the ambient IoT device accommodation, the wireless sensing function, and the AI-aware data sharing. Second, we identify the issues to satisfy those requirements in the current 5G technologies. Lastly, we pick up the 6G architectures proposed currently and discuss their pros and cons based on the requirements and issues pointed out.

DOI： 10.1109/ACCESS.2024.3395363

Scopus

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

Recently, there has been a surge of interest in Artificial Intelligence (AI) and its applications have been considered in various fields. Mobile networks are becoming an indispensable part of our society, and are considered as one of the promising applications of AI. In the Beyond 5G/6G era, AI will continue to penetrate networks and AI will become an integral part of mobile networks. This paper provides an overview of the collaborations between networks and AI from two categories, “AI for Network” and “Network for AI,” and predicts mobile networks in the B5G/6G era. It is expected that the future mobile network will be an integrated infrastructure, which will not only be a mere application of AI, but also provide as the process infrastructure for AI applications. This integration requires a driving application, and the network operation is one of the leading candidates. Furthermore, the paper describes the latest research and standardization trends in the autonomous networks, which aims to fully automate network operation, as a future network operation concept with AI, and discusses research issues in the future mobile networks.

DOI： 10.1587/transcom.2022TMI0001

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Highly accurate anomaly detection is indispensable for reliable communication services, and research on anomaly detection with AI/ML has been actively conducted . Detailed system-specific data as input for AI/ML, are essential for autonomous provisioning and failure management. This paper proposes a novel monitoring architecture for measuring detailed system-specific data in routers that comprise transport networks, as an essential element of mobile networks. Previously, vendor-proprietary router implementations were dominant and could only measure limited metrics (e.g., the CPU utilization rate and packet throughput). In recent years, however, the rise of cloud computing and SDNs has led to routers becoming more open and software-oriented. Therefore, we propose a novel eBPF-based monitoring method for routers. The evaluation results obtained by AI/ML show that anomaly detection can be achieved with high accuracy.

Scopus

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Large-scale failures in mobile networks cause congestion due to User Equipment (UE) reconnection. Though the 3rd Generation Partnership Project (3GPP) defines congestion control functions in Network Functions (NFs), such as the Access and Mobility Management Function (AMF), the control parameters are expected to be calculated in AMFs with depleted computational resources under congestion conditions. This paper proposes a congestion control scheme based on coordinating the Radio Access Network (RAN) and core networks. In this scheme, the orchestration platform calculates the traffic reduction rate at the base stations based on the statistics of RAN and core networks instead of the AMF during congestion. Simulation results show that the proposed method increases the time to convergence by only 8.9 percent compared to the theoretical limit. The study also discusses the issues to be considered in the 3GPP and O-RAN specifications for implementing the proposed method.

DOI： 10.1109/VTC2023-Spring57618.2023.10199592

Scopus

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

IoT devices are now used in many different fields and applications, and they generate a large amount of traffic when sending sensor data to the cloud for analysis. By offloading these computing tasks to edge computing, the network traffic on the core network and latency can be reduced. However, the resources at the edge are limited, making it difficult to respond to the rapidly expanding number of IoT devices. To solve the problem, extreme edge computing, which utilizes the computing resources of end devices for task offloading, is emerging. The conventional task execution methods in edge computing are unsuitable for extreme edge computing because of the nonuniformity of end devices and connectivity. To meet the requirements of extreme edge computing, we propose a novel WebAssembly container system that is portable, lightweight, and manageable. Our proposed system has two types of container engines working as native applications and Web applications. This enables the execution of general-purpose computing tasks on various devices with different CPU architectures and OSs. We evaluate our prototype implementation working on these devices to confirm the benefits and effects of our proposed system for extreme edge computing.

DOI： 10.1109/GLOBECOM54140.2023.10437269

Scopus

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

The flooding distributed denial of service (DDoS) attacks are recognized as one of the most considerable threats to security. In the B5G/6G era, as devices connected to mobile networks increase, it is easily predicted that mobile data communication traffic will increase massively and rapidly. This suggests that DDoS attacks traffic via mobile networks can become a thread more than before. To defend against DDoS attacks, the best way is to collaborate with multiple domain networks, i.e., source network, core network, and victim-end network. An ideal approach is to detect and protect against DDoS attacks in a location close to the attack source. Therefore in this paper, we design a collaborative system working between IP and mobile networks to defend against DDoS attacks and introduce a prototype of the proposed scheme. By demonstrating the packet filtering function in UPF, we show its feasibility and effectiveness in 5G/6G networks.

DOI： 10.1007/978-3-031-29056-5_2

Scopus

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This paper proposes an architecture and route control scheme of the layer 1 repeater-based IAB system, which can expand a high-frequency radio access area with high-quality communication service. Although repeaters just amplify and retransmit radio signals, the proposed system enables building a multi-hop network using beamforming and scanning. It introduces an external route control server to calculate the route tree under the limited hop count requirement and minimize the total route tree cost. This paper also shows its effectiveness through simulations using the NetworkX package.

DOI： 10.1109/VTC2023-Spring57618.2023.10199731

Scopus

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Incremental deployment of new Internet architecture is a key challenge for the smooth evolution of the current Internet. In NDN, the overlay-based deployment is considered as one of the promising options to provide NDN services over the Internet. To achieve an incremental deployment, it is required to design a bootstrapping mechanism that allows consumers to consistently access to an overlay NDN network in a situation where Autonomous Systems (AS) are gradually deploying NDN routers. In this paper, we analyzed the current bootstrapping and identified its potential issue in specifying the IP address of the closest NDN router. We propose a robust bootstrapping architecture that can work without specifying the exact IP address of a single NDN router. By using in-network indirection, our scheme can provide consistent access to the NDN network independent of the deployment status of each AS.

DOI： 10.1145/3517212.3559486

Scopus

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記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.1109/MIE.2021.3120235

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

In Named Data Networking (NDN), consumers can retrieve content from anywhere in the network, including from the server and routers' cache. Therefore, the Round-Trip Time (RTT) of packets can vary when downloading content in NDN compared to TCP, which establishes a session between a client and a specific server. The current transport layer protocol of NDN is mainly designed with reference to TCP. Its timer-based loss detection is not well designed for the nature of NDN, where the RTT of each packet can vary significantly, and leads to false loss detection. In this paper, we attempt to revisit the loss detection mechanism in NDN. We clarify the potential performance degradation of NDN due to the spurious timeouts and propose an NDN-PTO mechanism that improves the accuracy of loss detection by identifying spurious timeouts with a probe Interest. We evaluate the performance of NDN-PTO through a comprehensive simulation and describe its benefits.

DOI： 10.1109/GLOBECOM48099.2022.10001095

Scopus

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

To realize a 6G network, Cloud-Native is a key technology for improving the scalability, agility, and resilience of telecom networks. Kubernetes is the de-facto standard container orchestrator and adaptation to the Cloud-Native Network Function (CNF) infrastructure is progressing. However, several discrepancies exist between standard Kubernetes networking and CNF networking. In this paper, we analyze the discrepancies and clarify the telecom network requirements for Kubernetes. Then, we perform qualitative and quantitative evaluations on several network extensions developed as open-source software. From the results, we discuss the extensions that satisfy the requirements and represent the suitable combinations of network extensions for several CNF use cases.

DOI： 10.1109/GCWkshps56602.2022.10008579

Scopus

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Several new Internet architectures have been proposed to fill the gap between the original design of Internet and its current usage. These new architectures have been studied for more than 15 years, and their technical benefits have been widely validated. However, to date, these architectures have not been deployed in commercial networks. One of the reasons is that current Internet involves multiple players such as content providers and Internet Service Providers (ISPs), which makes it difficult to make significant changes. On the other hand, several studies have shown two trends of the current Internet, consolidation in web content delivery and flattening of the Internet topology. Web content delivery is dominated by the large Content Delivery Network (CDN) providers. Moreover, to improve communication quality, such providers connect directly to the eyeball ISPs, and this results in the flat topology. In this paper, we focus on whether these two trends, i.e., Internet flattening and consolidation, can ease the hurdle for deploying new architecture. Based on the measurements of DNS and network path, we verified the current trend of flattening and consolidation of content delivery on the Internet. We also investigated the incremental deployment scenario of new architecture under this environment. The results showed that a significant amount of traffic can be handled by a new architecture, if only a small set of autonomous systems cooperatively deploy it.

DOI： 10.1145/3488663.3493688

Scopus

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This paper revisits longest prefix matching in IP packet forwarding because an emerging data structure, learned index, is recently presented. A learned index uses machine learning to associate key-value pairs in a key-value store. The fundamental idea to apply a learned index to an FIB is to simplify the complex longest prefix matching operation to a nearest address search operation. The size of the proposed FIB is less than half of an existing trie-based FIB while it achieves the computation speed nearly equal to the trie-based FIB. Moreover, the computation speed of the proposal is independent of the length of IP prefixes, unlike trie-based FIBs.

DOI： 10.1145/3466826.3466842

Scopus

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記述言語：英語   掲載種別：研究論文（学術雑誌）

The emergence of fog computing has brought unprecedented opportunities to the Internet-of-Things (IoT) field, and it is now feasible to incorporate deep learning at the edge of the IoT network to provide a wide range of highly tailored services. In this article, we present a fog-based democratically collaborative learning scheme in which fog nodes collaborate on the model training process even without the support of the cloud, contributing to the advances of IoT in terms of realizing a more intelligent edge. To achieve that, we design a voting strategy so that a fog node could be elected as the coordinator node based on both distance and computational power metrics to coordinate the training process. Also, a collaborative learning algorithm is proposed to generalize the training of different deep learning models in the fog-enabled IoT environment. We then implement two popular use cases, including a user trajectory prediction and a distributed image recognition, to demonstrate the feasibility, practicality, and effectiveness of the scheme. More importantly, the experiments on both use cases are conducted through a real world, in-door fog deployment. The result shows that the scheme can utilize fog to obtain a well-performing deep learning model in the cloudless IoT environment while mitigating the data locality issue for each fog node.

DOI： 10.1109/JIOT.2020.3020911

Scopus

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記述言語：英語   掲載種別：研究論文（学術雑誌）

Localization has long been considered as a crucial research problem for pervasive sensing systems, especially with the arrival of big data era. Various techniques have been proposed to improve the localization accuracy by leveraging common wireless signals, such as radio signal strength indication (RSSI), collected from sensors placed in pervasive environments. However, the measured signal value can be easily affected by noise caused by physical obstacles in such sensing environment, which in turn compromises the localization performance. Hence, we present a novel RSSI-based area localization scheme using deep neural network (DNN) to explore the underlying correlation between the RSSI data and the respective sensor placement to achieve a superior localization performance. Moreover, to cope with the sensor data loss issue that commonly occurs during wireless sensor network (WSN) operation, an algorithm is designed to reconstruct the missing data for respective sensors in order to preserve the performance of DNN localization model. The effectiveness of the proposed scheme is verified with a real-world WSN testbed deployed inside an office building. The results demonstrate that the proposed scheme provides satisfactory prediction accuracy in area localization for pervasive sensing systems, regardless of the data loss issue that occurs with the respective sensors.

DOI： 10.1016/j.jnca.2020.102852

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

A global content delivery plays an important role in the current Internet. Information-Centric Networking (ICN) is a future internet architecture which attempts to redesign the Internet with a focus on the content delivery. However, it has the potential performance degradation in the global content delivery. In this paper, we propose an ICN performance enhancing proxy (ICN-PEP) to mitigate this performance degradation. The key idea is to prefetch Data packets and to serve them to the consumer with the shorter round trip time. By utilizing ICN features, it can be developed as an offline and state-less proxy which has an advantage of scalability. We evaluate the performance of ICN-PEP in both simulation and experiment on global testbed and show that ICN-PEP improves the performance of global content delivery.

DOI： 10.1587/transinf.2020NTP0007

Scopus

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This paper proposes an IP forwarding information base (FIB) encoding leveraging an emerging data structure called a learned index, which uses machine learning to associate key-position pairs in a key-value store. A learned index for FIB lookups is expected to yield a more compact representation and faster lookups compared to existing FIBs based on tries or hash tables, at the cost of efficient FIB updates, which is difficult to support with a learned index. We optimize our implementation for lookup speed, exploiting that for efficient FIB lookups it is enough to approximate the key-position pairs with a piece-wise linear function, instead of having to learn the key-position pairs. The experiments using real BGP routing information snapshots suggest that the size of the proposed FIB is compact and lookup speed is sufficiently fast regardless of the length of matched prefixes.

DOI： 10.1109/ICNP52444.2021.9651956

Scopus

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

With the rapid development of IoT (Internet of Things) technology, numerous sensors are being deployed to the smart society with the integration of IoT services. Since the collected sensor data reflect the current status of the surrounding environment, determining accurate positions for sensors is crucial from the stage of setting the sensors to realize meaningful sensor data analysis. In this paper, we propose LESAR, a localization system for environmental sensing using augmented reality. LESAR uses a smartphone camera with the AR (Augmented Reality) function to measure the distances between sensors, while the ID of each sensor is identified simultaneously by analyzing the collected Bluetooth signals. The vision-based approach used can enable three-dimensional localization through the simple use of a smartphone.

DOI： 10.1109/COMPSAC48688.2020.00-16

Scopus

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Named Data Networking (NDN) is a promising future Internet architecture which can overcome challenges in Multi-Access Edge Computing (MEC). In this paper, we focus on the forwarding strategy which is an essential part for realizing an NDN-based MEC architecture. Through extensive experiments on a testbed, we evaluate each default strategy in NDN with regard to three criteria: reliability, throughput, and overhead. We point out pros and cons of each strategy, and find two missing features, in-network recovery and load balancing, for improving the performance of MEC communication. Finally, we design a forwarding strategy with the above features which achieves higher throughput and reliability for end users than existing strategies while also reducing network congestion.

DOI： 10.1109/GLOBECOM42002.2020.9322485

Scopus

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記述言語：英語   掲載種別：研究論文（学術雑誌）

Equal load balancing for dispatching incoming packets to multiple threads is a crucial requirement in the stateful forwarding of multi-threaded software routers to achieve high-speed forwarding and low packet loss simultaneously. However, equal load balancing is not trivial for Named Data Networking (NDN) routers because of their stateful forwarding. In other words, the consistency of flow states should be maintained so that multiple threads do not access the states simultaneously. Sharding, wherein packets of the same flow are dispatched to the same thread while keeping loads of threads equal, has been proposed; however, in this study, we reveal that heavy hitters like popular content packets cause load imbalance, which may eventually cause packet losses. This study proposes a load balancing mechanism for NDN routers by exploiting the fact that states of flows need not be rigorously maintained when content packets are returned from caches at intermediate routers.

DOI： 10.1109/ACCESS.2020.3018555

Scopus

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