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Wireless sensor networks generate big-data which leads to overwhelming traffic in the networks. Compressed sensing (CS) can exploit signal sparsity to reduce the amount of traffic. We evaluate the performance of 1-bit CS with a circulant random bipolar measurement matrix. The results show that 1-bit CS can decrease traffic at higher degree in wireless sensor networks compared to the conventional CS...
Collecting real-world information is an important task for humanitarian applications. To alleviate this cumbersome task, we have presented Choco, a low-power, end-to-end reliable collection protocol for wireless sensor networks. Sensor nodes with Choco can construct multi-hop wireless networks without awareness of network topology thanks to simultaneous flooding, which is a recently proposed flooding...
TDMA is more suitable for high throughput data collection than CSMA. Yet, in wireless sensor network plain TDMA-based protocols require complex scheduling. In case of node failures, plain TDMA is hard to recover connection and achieve robust data collection due to the complex scheduling burden. Toward robust data collection, it is important to develop a collection protocol capable of topology adaptability...
We present a high throughput data gathering protocol for wireless sensor network. Different from existing works we elaborate a token-scheduled multi-channel TDMA protocol named TKN-TWN that provides better scalability and topology adaptability. TDMA is more suitable for high throughput data collection than CSMA. However, TDMA-based protocols require complex scheduling of the transmission time slot...
We present a design and evaluation of Choco, a low-power, end- to-end reliable collection protocol for wireless sensor networks. We construct Choco on Glossy, which is a recently presented efficient flooding scheme exploiting constructive-interference phenomena. Although Glossy is originally developed for flooding, it can be regarded as a networking primitive which provides low-power, low- delay,...
To reduce the complexity of scheduling while exploiting the advantages of TDMA-based data collection, we propose TKN-TWN, a token-scheduled multi-channel data collection protocol. The TKN-TWN uses two tokens to arbitrate data-packet transmissions and associates the ownership of tokens with transmission slot assignment. For the reduction of scheduling burden, the TKN-TWN provides topology adaptability...
Leaf Area Index (LAI) is one of indicators in observing plant growth. Continuous estimation of LAI can increase productivity of agriculture. Since LAI has high correlation with light transmittance into under-foliage, monitoring light transmittance makes it possible to estimate LAI continuously. In this paper, we present a design, implementation, and evaluation of a continuous LAI monitoring system...
The present paper introduces a power service discovery system. The power service discovery system realizes new power services on a smart grid. The new power services are based on the selection of generations, which enables us to provide/receive electricity under specific conditions. We describe the design and implementation of the power service discovery system. Our implementation constructs a demonstration...
Data-intensive wireless sensor network applications, such as structural health monitoring and earthquake monitoring, require high throughput bulk data collection. Based on the fact that each node stores the same amount of sensor data, we propose a Maximum-Subtree-First Collection Protocol (MSFCP), which adopts Maximum-Subtree-First scheduling on top of multi-channel block transfer to maximize overall...
For the efficient use of spectrum resource, it is important to understand spectrum occupancy at a high spatial resolution, so a large number of measurement locations are required. In this work, in order to increase measurement locations, we design and implement a low-end spectrum sensor which is capable of switching to different channels in a spectrum range of the UHF band. The spectrum sensor can...
We study a network structure for efficient information dissemination that leverages location-based real-time applications operating in a distributed system. Gossip-based information dissemination is a promising method for a large-scale system to keep nodes in the network quickly updated with new information. The information dissemination efficiency depends strongly on the underlying network structure,...
A suitable spectrum policy is essential to allow efficient use of the radio spectrum. The Japanese government currently employs a Command and Control (C&C) regime, but measures must be taken to speed up governmental decisions. The first step is to obtain spectrum utilization data which can form the basis of such decisions. This paper describes the design, implementation and evaluation of a distributed...
With the development of DLNA technology, more and more DLNA devices appear in our lives. We can extract users' activity events from the operation history of DLNA devices, and provide various services based on them. In this paper, we discuss how to detect anomalous events from operation history of DLNA devices. As the basic technology, we first propose DLNA Probe, a system to acquire operation history...
Power consumption in office networks has become a major issue due to its running cost. In order to reduce the power consumption, several approaches have been proposed such as Energy Efficient Ethernet (EEE) and Energy Efficient Wireless aggregation (EEW). In this research, we develop an analytical model and apply the model to evaluate and compare performance of the existing technologies. The parameters...
Peter Drucker investigated the impact of railroad on society. “The technology of the steam engine did not end with the railroad.” Although “the railroad made the Industrial Revolution accomplished fact”, the boom it triggered lasted almost a hundred years. The dynamics of the technology shifted to totally new “social institutions: the modern postal service, the daily paper, investment banking, and...
We present a wake-up wireless communication system, which can drastically reduce idle listening energy for long idle listening applications by using a wake-up wireless module. We consider chance encounter communication, which is communication during opportunistic encounters, as a long idle listening application. There are three requirements for applying the wake-up system to chance encounter communication:...
We design a hybrid optical add/drop node combining Multi-Wavelength Optical Packet and Optical Switching for Metro-Area Ring Networks. The feasibility of hybrid switching has been confirmed at a 120 Gb/s network testbed.
Using newly developed PLZT-based OBS core node, low-loss Ether-frame transmission with application-layer connectivity is demonstrated over 92-km 2-hop field testbed. Recent progresses in developing OPS/OCS hybrid router are also reviewed.
Random access process of LTE (long term evolution) system is carried out exploiting the superior correlation property of random access code. Each user unit transmits randomly selected random access code, and the Node B (base station) detects each code by correlating the received signal with all possible random access codes. By comparing the correlation output power to the threshold, randomly selected...
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