Yoshimasa Ishi

A P2P-Based Sensor Data Stream Delivery Method to Accommodate Heterogeneous Cycles

Due to the prevalence of sensors such as security cameras or environmental monitoring, sensor data stream delivery which means delivering the observed data continuously attracts great attention. For sensor data stream delivery, various methods to distribute communication loads in the case of delivering the same sensor data streams to multiple clients have been studied. Although these methods assume that the sensor data streams have the same data delivery cycles, data delivery cycles sometimes differ. Hence, we propose a P2P-based method to distribute communication loads in the case of delivering the sensor data streams that have different data delivery cycles. The proposed method distributes communication loads by redelivering the sensor data that have the same delivery time but are included in different sensor data streams. We evaluated the effectiveness of the proposal in simulations and confirmed the load distribution in the case of many receivers at the same time.

A delivery method considering communication loads for sensor data stream with different collection cycles

Due to the prevalence of sensors such as security cameras or environmental sensors, sensor data stream delivery which means delivering the sensor data every cyclic collection attracts great attention. For sensor data stream delivery, various methods to distribute communication loads in the case of delivering the same sensor data streams to multiple clients have been studied. Although these methods assume that the sensor data streams have the same data collection cycles, data collection cycles sometimes differ. Hence, we propose a method to distribute communication loads in the case of delivering the sensor data stream that have different data collection cycles. The proposed method distributes communication loads by re-delivering the sensor data that have the same collection time but are included in different sensor data streams.

Cooperative caching by clients constructing a peer-to-peer network for push-based broadcast

In this paper, we propose new cooperative caching strategies by multiple clients in a push-based broadcast system, which replaces cached items based on benefits of the waiting time. A key idea is that the clients construct a logical peer-to-peer network and each of them determines the replacement of its own cache by taking into account access probabilities to data items from neighboring clients and the broadcast periods of data items or the times remaining until these items are broadcasted next. We confirm that the proposed strategies reduce the average response time by simulation experiments.

X-Sensor: Wireless Sensor Network Testbed Integrating Multiple Networks

This chapter describes a wireless sensor network testbed, named XSensor, that integrates multiple sensor networks. X-Sensor manages multiple wireless sensor networks constructed at different sites, which can be accessed by remote users. This makes easy for users to conduct experiments in different environments. Moreover, X-Sensor provides real sensor data acquired by sensor nodes in each sensor network, which are useful for researchers working on research fields related to sensor data such as sensor data mining and analysis.

A P2P Delivery Method for Sensor Data Stream Based on Load Estimation from Collection Cycles

Due to the prevalence of sensors such as security cameras or environmental monitoring, sensor data stream delivery which means delivering the observed data continuously attracts great attention. For sensor data stream delivery, receivers collect data in various cycle by the use of them. We proposed a P2P-based method to distribute communication loads in the case of delivering the sensor data stream that have different data collection cycles. Although the existing method distributes communication loads by re-delivering the sensor data that have the same collection time, the load concentration to the longer cycle receivers is probable. Therefore, we propose a P2P delivery method to distribute communication loads by the estimation of each receivers loads and re-delivering from the lowest load receiver. We evaluated the effectiveness of proposal in simulation. By the result of simulations, we confirmed the load distribution in the case of many receivers at same time.

Range-Key Extension of the Skip Graph

In the Skip Graph, which is a structured overlay network that supports range retrievals, a key is supposed to consist of a single value. Therefore, the Skip Graph cannot perform range-to-range retrievals. In the present research, we extend the Skip Graph, enabling it to retain a range as a key, and propose the Range-Key Skip Graph, which can perform range-to-range retrievals. We also implement the proposed scheme and evaluate it on the PlanetLab.

A Load Distribution Method Based on Distributed Hashing for P2P Sensor Data Stream Delivery System

Due to the prevalence of sensors such as security cameras or environmental monitoring, sensor data stream delivery which means delivering the observed data continuously attracts great attention. Currently, the methods to distribute communication loads by relay nodes in the case of delivering the sensor data streams that have different data delivery cycles are proposed. However, in the existing methods, since the specific node builds delivery paths and notifies to the related nodes, the delivery paths are necessary to be built and notified again when nodes join or leave. Therefore, in this paper, we propose a method which determines relay nodes based on distributed hashing and constructs delivery paths autonomously by each node. We evaluated the effectiveness of proposal in simulation.

A Lightweight Multi-receiver Encryption Scheme with Mutual Authentication

In this paper, we propose a lightweight multi-receiver encryption scheme for the device to device communications on Internet of Things (IoT) applications. In order for the individual user to control the disclosure range of his/her own data directly and to prevent sensitive personal data disclosure to the trusted third party, the proposed scheme uses device-generated public keys. For mutual authentication, third party generates Schnorr-like lightweight identity-based partial private keys for users. The proposed scheme provides source authentication, message integrity, replay-attack prevention and implicit user authentication. In addition to more security properties, computation expensive pairing operations are eliminated to achieve less time usage for both sender and receiver, which is favourable property for IoT applications. In this paper, we showed a proof of security of our scheme, computational cost comparison and experimental performance evaluations. We implemented our proposed scheme on real embedded Android devices and confirmed that it achieves less time cost for both encryption and decryption comparing with the existing most efficient certificate-based multi-receiver encryption scheme and certificateless multi-receiver encryption scheme.

A large-scale data collection scheme for distributed Topic-Based Pub/Sub

In this paper, we propose a scalable data collection scheme for distributed Topic-Based Pub/Sub (TBPS) messaging that can prevent overloads in network processes in the large-scale IoT applications. Our proposal scheme employs “Collective Store and Forwarding,” which stores and merges multiple small size messages into one large message along a multi-hop tree structure on the structured overlay for TBPS, taking into account the delivery time constraints. This makes it possible to reduce the overhead of network process even when a large number of sensor data is published asynchronously. We also propose a tree construction method for adjusting maximum network process load on nodes called the “Adaptive Data Collection Tree.” Simulation results show that compared to existing schemes, our proposal schemes can reduce a network occupation time by 90% to collect data from 10,000 publishers.

A P2P streaming system for delivering sensor data streams with different collection cycles

Due to the increasing use of sensors, such as security cameras and environmental sensors, sensor data stream delivery, the delivering of sensor data through cyclic collection, is attracting considerable attention. Various methods for distributing communication loads, when delivering the same sensor data streams to multiple clients, have been investigated. Our research team developed a peer-to-peer streaming system for distributing communication loads when delivering sensor data streams with different data collection cycles. In this study, we performed a comparative system evaluation utilizing the JGN-X PIAX testbed provided by the NICT.