Abstract
〈Vol.5 No.1(2012.1)〉
Titles
[Contributed Papers]
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■ AWireless Self-Powered Urinary Incontinence Sensor System
Ritsumeikan University・Ami TANAKA, Fumiyasu UTSUNOMIYA, and Takakuni DOUSEKI
A self-powered urinary incontinence sensor system consisting of a urine-activated
coin battery and a wireless transmitter has been developed as an application
for wireless biosensor networks. The urine-activated battery makes possible
both the sensing of urine leakage and self-powered operation. An intermittent
power-supply circuit that uses an electric double-layer capacitor (EDLC)
with a small internal resistance suppresses the supply voltage drop due
to the large internal resistance of the battery. This circuit and a 1-V
surface acoustic wave (SAW) oscillator reduce the power dissipation of
a wireless transmitter. The SAW oscillator quickly responds to the on-off
control of the power supply, which is suitable for intermittent operation.
To verify the effectiveness of the circuit scheme, the authors fabricated
a prototype sensor system. When the volume of urine is 0.2 ml, the battery
outputs a voltage of over 1.3 V; and the sensor system can transmit signals
over a distance of 5 m.
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■ H∞ Design of Periodically Nonuniform Interpolation and Decimation for
Non-Band-Limited Signals
Kyoto University・Masaaki NAGAHARA,Texas Tech University・ Masaki OGURA
and Kyoto University・Yutaka YAMAMOTO
In this paper, we consider signal interpolation of discrete-time signals
which are decimated nonuniformly. A conventional interpolation method is
based on the sampling theorem, and the resulting system consists of an
ideal filter with complex-valued coefficients. While the conventional method
assumes band limitation of signals, we propose a new method by sampled-data
H∞ optimization. By this method, we can remove the band-limiting assumption
and the optimal filter can be with real-valued coefficients. Moreover,
we show that without band-limited assumption, there can be the
optimal decimation patterns among ones with the same ratio. By examples, we show the effectiveness of our method.
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■ Web-Based Image Viewer for Monitoring High-Definition Agricultural Images
Shinshu University・Kazuki KOBAYASHI, Shohei TODA，
Fumitoshi KOBAYASHI and Yasunori SAITO
This paper describes a Web-based image viewer which was developed to monitor
high-definition agricultural images. In the cultivation of crops, physiological
data and environmental data are important to increase crop yields. However,
it is a burden for farmers to collect such data. Against this backdrop,
the authors developed a monitoring system to automatically collect high-definition
crop images, which can be viewed on a specialized Web-based image viewer.
Users can easily observe detailed crop images over the Internet and easily
find differences among the images. The authors experimentally installed
the monitoring system in an apple orchard and observed the apples growing
there. The system has been operating since August 11, 2009. In this paper,
we confirm the ability of the monitoring system to perform detailed observations,
including tracing the progress of a disease that affects the growth of
an apple.
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■ Quantitative Evaluation of Surface Color of Tomato Fruits Cultivated
in Remote Farm Using Digital Camera Images
Mie University・Atsushi HASHIMOTO, Ken-ichiro SUEHARA, and Takaharu KAMEOKA
To measure the quantitative surface color information of agricultural products
with the ambient information during cultivation, a color calibration method
for digital camera images and a remote monitoring system of color imaging
using the Web were developed. Single-lens reflex and web digital cameras
were used for the image acquisitions. The tomato images through the post-ripening
process were taken by the digital camera in both the standard image acquisition
system and in the field conditions from the morning to evening. Several
kinds of images were acquired with the standard
RGB color chart set up just behind the tomato fruit on a black matte, and
a color calibration was carried out. The influence of the sunlight could
be experimentally eliminated, and the calibrated color information consistently
agreed with the standard ones acquired in the system through the post-ripening
process. Furthermore, the surface color change of the tomato on the tree
in a greenhouse was remotely monitored during maturation using the digital
cameras equipped with the Field Server. The acquired digital color images
were sent from the Farm Station to the BIFE Laboratory of Mie University
via VPN. The time behavior of the tomato surface color change during the
maturing process could be measured using the color parameter calculated
based on the obtained and calibrated color images along with the ambient
atmospheric record. This study is a very important step in developing the
surface color analysis for both the simple and rapid evaluation of the
crop vigor in the field and to construct an ambient and networked remote
monitoring system for food security, precision agriculture, and agricultural
research.
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■ PAVENET OS: A Compact Hard Real-Time Operating System for Precise Sampling
inWireless Sensor Networks
The University of Tokyo・Shunsuke SARUWATARI, MakotoSUZUKI, and Hiroyuki
MORIKAWA
The paper shows a compact hard real-time operating system for wireless
sensor nodes called PAVENET OS. PAVENET OS provides hybrid multithreading:
preemptive multithreading and cooperative multithreading. Both of the multithreading
are optimized for two kinds of tasks on wireless sensor networks, and those
are real-time tasks and best-effort ones. PAVENET OS can efficiently perform
hard real-time tasks that cannot be performed by TinyOS. The paper demonstrates
the hybrid multithreading realizes compactness and low overheads, which
are comparable to those of TinyOS, through quantitative evaluation. The
evaluation results show PAVENET OS performs 100 Hz sensor sampling with
0.01% jitter while performing wireless communication tasks, whereas optimized
TinyOS has 0.62% jitter. In addition, PAVENET OS has a small footprint
and low overheads (minimum RAM size: 29 bytes, minimum ROM size: 490 bytes,
minimum task switch time: 23 cycles).
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■ Mobile Phone-Based Field Monitoring for Satsuma Mandarin and Its Application
to Watering Advice System
NEC System Technologies Ltd・Toshiyuki KAMIYA,
Nagisa NUMANO, Hiroyuki YAGYU and Hideo SHIMAZU
This paper describes a mobile phone-based data logging system for monitoring
the growing status of Satsuma mandarin, a type of citrus fruit, in the
field. The system can provide various feedback to the farm producers with
collected data, such as visualization of related data as a timeline chart
or advice on the necessity of watering crops. It is important to collect
information on environment conditions, plant status and product quality,
to analyze it and to provide it as feedback to the farm producers to aid
their operations. This paper proposes a novel framework of field monitoring
and feedback for open-field farming. For field monitoring, it combines
a low-cost plant status monitoring method using a simple apparatus and
a Field Server for environment condition monitoring. Each field worker
has a simple apparatus to measure fruit firmness and records data with
a mobile phone. The logged data are stored in the database of the system
on the server. The system analyzes stored data for each field and is able
to show the necessity of watering to the user in five levels. The system
is also able to show various stored data in timeline chart form. The user
and coach can compare or analyze these data via a web interface. A test
site was built at a Satsuma mandarin field at Kumano in Mie Prefecture,
Japan using the framework, and farm workers monitor in the area used and
evaluated the system.
▲ ■ Slope Disaster Detection System Using Sensor Networks and Its Field
Experiment Evaluations
Osaka University・Keigo KOIZUMI, Nagaoka University of Technology・Kenji
HIRATA,
Osaka University・Kazuhiro ODA,Earth Watch Corporation・Yukishige FUJITA,
Ritsumeikan University・Sadayuki KAMIDE and Tohru WATANABE
The authors developed a slope disaster monitoring system using distributed
sensors. The sensor node has wireless communication and tilt detection
capabilities. Each sensor node communicates with others and sends the corrected
data to a base station that can send an alert message to administrators
in case of emergency. Wireless communication abilities and the accuracy
of an acceleration sensor that will be used as a tilt detection sensor
of the developed sensor nodes were checked through a small field test in
the Osaka University campus. The developed slope disaster monitoring system
was installed on a slope along the Chugoku Expressway, and a performance
evaluation experiment has been performed over 8 months. Throughout the
field experiment study, the authors found that the developed sensor network
system is effective to detect a slope disaster. They also found that, depending
on geometric arrangements of the nodes, for establishing a steady network
connection at the starting up stage of the system, relatively long time
was required. Efficient sensor arrangements may require further studies.
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■ A Self-Health Monitoring System for aWireless Sensor Network Used in
Bridge Diagnosis
Waseda University・Haitao XIAO, Tansheng LI, and Harutoshi OGAI
For bridge diagnosis, the authors developed a wireless sensor network (WSN)
to measure and gather the vibration data of bridges. In previous bridge
diagnosis experiments, node failure and data packet loss occurred in the
WSN, which caused some corruption in the collected data and hence the WSN
could not be used to analyze the health status of the bridge. Furthermore,
it was always difficult to determine the location of the nodes in order
to ensure the link quality, when all the nodes of the WSN deployed for
the first time. In this paper, a self-health monitoring system called distributed
localized decision monitoring system (DLDMS) is presented to monitor the
health of the WSN. Key features
of the system include high detection accuracy, high responsiveness, and
low energy consumption. Experimental data is given based on experiments
at Kitakyushu in Japan.
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