Yao-Min Fang

Design of a Multifunctional Wireless Sensor for In-Situ Monitoring of Debris Flows

Debris flows carrying saturated solid materials in water flowing downslopes often cause severe damage to the lives and properties in their path. Close monitoring and early warning are imperative to save lives and reduce damage. Current debris-flow-monitoring systems usually install sensor equipment along the riverbanks and mountain slopes to detect debris flows and track their data. Unfortunately, most of this equipment indirectly collects data only from a distance. So far, there is no way to understand what is happening inside a debris flow and to collect its internal parameters, not to mention doing this in real time. To answer this challenge, this paper presents a novel multifunctional wireless sensor for monitoring debris flows. The core idea is to let these sensors drift with the debris flow, to collect flow information as they move along, and to wirelessly transmit the collected data to base stations in real time. The design of such a sensor needs to address many challenging issues, including cost, deployment efforts, long-term standby, and fast reaction. This paper addresses these issues and reports our evaluation results.

Using mobile wireless sensors for in-situ tracking of debris flows

Most debris flow monitoring systems deployed today use indirect means to track information regarding debris flows. In this work, we introduce a novel debris flow monitoring system for in-situ and direct tracking of debris flows in real-time. The core idea is to throw wireless sensors into the debris flows and collect flow information as they move along. We will describe the design of the wireless sensors and present some preliminary performance results.

The Tube: A Rapidly Deployable Wireless Sensor Platform for Supervising Pollution of Emergency Work

Natural disasters, such as severe storms and earthquakes, often cause bridge collapses and road damage. To ensure public safety, governments must repair damage as soon as possible. The jackhammers, dozers, and piling machines used in emergency work always generate significant amounts of pollution, including noise and vibration, and thus, pollution levels should be monitored in an effort to protect the local environment. We propose the Tube, a wireless sensor network platform that can be easily and rapidly deployed for monitoring pollution at multiple emergency work locations. Users may install Tubes in multiple locations to monitor pollution simultaneously without having to worry about the issues affecting traditional wireless communication. We designed and implemented this platform to monitor pollution at an actual site of emergency work; the results verify this system meets all expected goals and can offer valuable information for local authorities to control pollution effectively on emergency work sites.

Design and implementation of non-autonomous mobile wireless sensor for debris flow monitoring

This demo presents a mobile wireless sensor system for debris flow monitoring. The objective of this system is to realize long-term and effective debris flow surveillance using low cost wireless sensors. In the system, a set of robust wireless sensors are designed to deploy on riverbed and cooperatively observe the moving debris flows. Our mobile sensors are intended to be carried along by the debris flow. As the sensors move along, they are able to measure the internal parameters, such as vibration frequency, amplitude, moving direction and velocity, of the debris flow. By utilizing the proposed energy-saving mechanism on the WSN platform, the mobile sensors can continuously operate up to six months with merely two alkaline D cell batteries. The proposed system provides the abilities to collect high-fidelity data for civil engineering applications to analyze and determine the occurrence of debris flows, as well as estimate the damage.

Development of a long-lived, real-time automatic weather station based on WSN

The scale of weather monitoring is limited by the cost of the automatic weather stations (AWS), which is mainly the cost of high precision instruments and long-distance wireless telecommunication equipments. We propose a wireless sensor network (WSN) based AWS, which takes advantage of the low-cost, real-time and infrastructure-free characteristics of WSN [1]. We can therefore extend the scale of weather monitoring without increasing the number of telecommunication equipments. This WSN-based AWS is able to cover a plane and gather multiple sets of weather measurements in real-time at a better data resolution.

Open-Source Wireless Sensor System for Long-Term Monitoring of Slope Movement

Power consumption is one of the major issues associated with deploying a wireless sensor to monitor natural environments in the real world. It is not practical to frequently replace the battery of a sensor that is located in a remote mountainous area. While considering to save valuable energy, the sensor must be able to detect a particular event in a timely manner and report data. To satisfy these requirements, in this paper, we present a wireless sensor system, termed SMARTCONE, which is designed to monitor the slope movement and minimize the standby power consumption, while remaining active to detect events. Multiple SMARTCONEs need to synchronously change their operation modes to collect the physical parameters and transmit raw vibration data simultaneously. SMARTCONE is consuming a power of only 0.05 mA at 3.6 V in standby mode, which is significantly less than that consumed by the previous design. As far as we know, SMARTCONE is an unprecedented instrument for the monitoring of slope movement; no other instruments can achieve such a low-energy consumption while being triggered by external vibration and managed remotely. These complicated issues are considered while designing the SMARTCONE, whose performance is then evaluated. In order to prevent redundant effort and to reduce the entry-level knowledge required by the users who wish to design a system, and to promote the use of this design for monitoring natural environments, we would like to open source the design of SMARTCONE for the public. It can be modified for use in other applications to satisfy their requirements without the need to build from scratch.

An open-source wireless mesh networking module for environmental monitoring

Wireless mesh networking extends the communication range among cooperating multiple low-power wireless radio transceivers and is useful for collecting data from sensors widely distributed over a large area. By integrating an off-the-shelf wireless design, such as the XBee module, development of sensor systems with mesh networking capability can be accelerated. In this study, the design of an open-source wireless network module is introduced, which integrates the functions of network discovery, routing control, and transmission scheduling. In addition, this design is provided in an open-source format in order to promote the use of wireless mesh networking for environmental monitoring applications. Testing of the design and the proposed networking module is reported. For a 10-node implementation an average packet delivery ratio is 95.58%. The proposed system was demonstrated to have the advantages of low-cost combined with high reliability and performance. The proposed design can aid scientists to implement monitoring applications without the complications of complex wireless networking issues.

The design considerations of a sensor grid for monitoring precipitation in debris-flow-prone areas

The debris flows caused by typhoon Morakot in August 2009 killed more than 600 people and caused US

Poster Abstract: An Extremely Long Standby Time Wireless Sensor System for Debris Flow Monitoring

500 million in damages to agriculture and forestry of Taiwan. Many lives can be saved if we can estimate the occurrence of debris flows and issue timely warnings to inhabitants. Previous literatures [1] have shown that rainfall is highly correlated with debris flows. Thus, the first step to debris flow monitoring and warning is to collect high-resolution, real-time precipitation in the debris-flow-prone areas. In this paper we discuss the considerations of designing a low-cost WSN-based rain gauge grid, which provides highresolution mapping of precipitation. Preliminary experimental results are presented.

Exploiting the tradeoff between fast wakeup and long standby in event-monitoring WSN

The one of the major difficulties in deploying a wireless sensor to monitor debris flow in the real world is power consumption. Frequently replacing the battery of a sensor that is located in a remote mountainous area is not practical. In this study we examine the newly-introduced wireless debris flow sensor, SMARTCONE, which is designed to minimize the standby power consumption, but still keep alert to detecting debris flow. During standby periods, SMARTCONE turns off all major components and uses an accelerometer to sense vibration generated by moving debris flow, and it wakes up SMARTCONE for collecting the parameters of a moving debris flow. Multiple SMARTCONEs need to change operation modes between standby and wake up, collect physical parameters, and transmit data simultaneously, and these issues are kept in mind while designing the system. The performance of vibration detection, data transmission and records of GPS trajectories are evaluated to ensure the accuracy of the design.