Ze Zhao

Chinese Academy of Sciences, Peping, Beijing, China

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Publications (21)4.68 Total impact

  • Zijian Wang · Ze Zhao · Dong Li · Li Cui
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    ABSTRACT: Currently, salvage is considered as an effective way for protecting ecosystems of inland water from toxin-producing algal blooms. Yet, the magnitude of algal blooms, which is the essential information required for dispatching salvage boats, cannot be estimated accurately with low cost in real time. In this paper, a data-driven soft sensor is proposed for algal blooms monitoring, which estimates the magnitude of algal blooms using data collected by inexpensive water quality sensors as input. The modeling of the soft sensor consists of two steps: 1) magnitude calculation and 2) regression model training. In the first step, we propose an active learning strategy to construct high-accuracy image classification model with ~50 % less labeled data. Based on this model, we design a new algorithm that recognizes algal blooms and calculates the magnitude using water surface pictures. In the second step, we propose to use Gaussian process to train the regression model that maps the multiparameter water quality sensor data to the calculated magnitude of algal blooms and learn the parameters of the model automatically from the training data. We conduct extensive experiments to evaluate our modeling method, AlgaeSense, based on over 200 000 heterogeneous sensor data records collected in four months from our field-deployed sensor system. The results indicate that the soft sensor can accurately estimate the magnitude of algal blooms in real time using data collected by just three kinds of inexpensive water quality sensors.
    No preview · Article · Jan 2015 · IEEE Sensors Journal
  • Zijian Wang · Ze Zhao · Dong Li · Li Cui · Xinyu Liu
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    ABSTRACT: The frequent occurrence of toxin-producing algal blooms is a serious concern for the ecological status of inland water and for human and animal health. In this paper, camera sensor networks are used to monitor algal blooms in lake for the first time. A distributed machine learning based algal blooms recognition (DMLAR) algorithm is proposed and implemented on embedded sensor nodes. DMLAR accurately recognises algal blooms and estimates their amounts in real-time based on the pictures of water surface. The machine learning model used by DMLAR is constructed by designing an active learning task, which is accomplished by collaborative embedded sensor nodes in a distributed manner. Extensive field experiments with large dataset are performed on the system deployed in lake since May 2010. Experiment results show that DMLAR outperforms two widely used methods both in terms of estimation accuracy and execution time, using nearly the same memory and energy.
    No preview · Article · Jan 2015 · International Journal of Sensor Networks
  • Le Zhang · Ze Zhao · Dong Li · Qiang Liu · Li Cui
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    ABSTRACT: This paper presents the design, deployment and empirical study of a wildlife monitoring system with heterogeneous wireless communication network. The system mainly helps the zoologist to monitor the elks' habits, distribution pattern as well as the living environment. In order to meet the demands of practical applications, the system is designed with different wireless communication networks, which supports protocol of IEEE 802.15.4/ ZigBee networks and IEEE 802.11b WLANs. Because of the heterogeneous characteristics of the networks, the energy consumption is different with various communication modules. It is necessary to adapt the appropriate power management scheme according to different communication sub-network. Since the network compose the lowpower nodes without any energy supply, the performance of energy-saving scheme employed in this network has an influence on lifetime of the whole system. Thus we introduce a power management scheme which can reduce the energy expenditure of the system effectively. The working overhead can be reduced to 53.18% under the 95.23% reliability of the communication from the analysis of the experiment result.
    No preview · Article · Jan 2013 · Ad Hoc & Sensor Wireless Networks
  • Qiang Liu · Ze Zhao · Li Cui
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    ABSTRACT: Dynamic spectrum access (DSA) networks can significantly improve the networks performance and efficiency of spectrum utilization. To harness this capability, spectrum sensing is a fundamental problem for DSA networks. This demonstration shows our wideband compressed spectrum sensing (WCSS) platform. This platform supports the controllable spectrum environment, high performance and low cost wideband spectrum sensing based USRP2, powerful and flexible compressed sensing computing platform based MATLAB. With this platform, we can research the wideband compressed spectrum sensing algorithm by actual and controllable spectrum environment.
    No preview · Article · Aug 2012
  • Dong Li · Zijiang Wang · Chenda Hou · Le Zhang · Ze Zhao · Li Cui
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    ABSTRACT: Facing the still unclear growth regularity of blooms, we propose rapid lightweight estimating method for the discovery of algae blooms. An application-specific approximate algorithm for timely dispatching salvaging boats is designed to minimize the total cleanup time.
    No preview · Article · Jun 2012
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    ABSTRACT: Wireless sensor networks will suffer severe performance degradation in communication reliability and throughput when interfered by co-located Wifi devices. When multiple sensor networks with different priority are interfered by Wifi devices, it is of great significance to allocate channels according to their priority as well as take into consideration the overall communication reliability and throughput. To address this problem, a channel allocation scheme to mitigate Wifi interference, called EasiCAP (Channel Allocation for wireless sensor networks with Priority), is presented. The scheme employs an external interference model, which is based on interference signal strength and activity ratio, to measure Wifi interference in each channel of sensor networks. In addition, a receiver-centric interference model is used to gauge internal interference amongst different sensor networks. Based on the measurements of external interference and internal interference, each sensor network independently selects its working channel in real time via a localized greedy algorithm in order to assign channels according to priority and also reduce the overall interference of all sensor networks as much as possible. Then, the sensor network performs one of the three operations, i. e., channel keeping, channel swapping, and channel preempting, based on the channel selection decision. Testbed experiments and simulations are conducted to verify the effectiveness of the proposed scheme. The experimental results demonstrate that EasiCAP can provide differentiated communication reliability and throughput corresponding to the network priority. Also, it has higher average communication reliability and throughput than existing schemes. Furthermore, it does not introduce significant overhead.
    No preview · Article · Mar 2012 · Chinese Journal of Computers
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    Dong Li · Ze Zhao · Li Cui · He Zhu · Le Zhang · ZhaoLiang Zhang · Yi Wang
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    ABSTRACT: Nowadays, the harmful blue-green algae blooms on lakes threaten the daily life of millions of people in China. We designed and developed a cyber physical networking system on Lake Tai for the monitoring and cleanup of the water blooms which is at work in Wuxi City, Jiangsu Province. We designed the sensor device and algorithm to monitor the order of severity of algae bloom. A GIS-based management website is built for the end user to monitor the whole system. In this paper, we focus on the agile sensor and actuator control (ASAC) mechanism to dispatch salvaging boats. The location area and the order of severity of a water bloom change rapidly with the climatic, the terrain and the sewage disposal system. The location and the capacity of salvaging boat are also in changing when the system is running. ASAC is designed to generate optimal dispatch plan in the changing environment. This mechanism also balances workloads among the boats and among the algae factories to achieve an overall high working efficiency. Through the tests in the real system, ASAC largely saved human resource and increased the work efficiency in the cleaning up process.
    Full-text · Conference Paper · May 2011
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    ABSTRACT: Traditional Chinese Pulse Diagnosis is a convenient and noninvasive method for disease diagnosis and healthcare. We have designed and implemented a Chinese wrist-pulse retrieval system based on the principle of Traditional Chinese Pulse Diagnosis (TCPD), called EasiCPRS. It is designed to be small in size, low in cost, with flexibility in deployment, and simplicity in operation. The contributions of this work are: 1. The wrist-pulse at "cun, guan and chi"points over the radial artery are obtained by applying a moderate and adjustable taking pressure during wrist-pulse retrieval. 2. A wrist-pulse signal conditioning circuit and a robust external taking pressure control algorithm are designed to overcome low signal-to-noise ratio (SNR). 3. A lightweight algorithm for wrist-pulse feature extraction is achieved on a resource-constrained platform to economize energy and bandwidth. We developed EasiCPRS prototype, trained and verified the performance of the system by collecting and analyzing thousands of wrist-pulse samples from volunteers in a number of different health conditions such as hypertension, pregnancy and so on which were diagnosed by doctors in hospital. The experimental results showed potential usefulness of the system in disease diagnosis and healthcare.
    Full-text · Conference Paper · Jan 2011
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    ABSTRACT: In this paper, we propose EasiTest, a multi-radio testbed for heterogeneous wireless sensor networks (WSN). Two types of sensor nodes, specifically, high speed multi-radio node (EZ271) and low speed single radio node (EZ521) are developed. An administration platform is provided to monitor and control the testbed. EasiTest enjoys high flexibility, powerful processing capability and ease of expansion. EasiTest provides a powerful tool not only for the study and evaluation of large scale, heterogeneous sensor networks, but also for quick prototyping of practical WSN applications. To demonstrate the capability of the testbed, we study the co-existence problem of IEEE 802.11 and IEEE 802.15.4. Guidelines are given on channel allocation and network parameter configuration to minimize the interference.
    Preview · Conference Paper · Dec 2010
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    Qiang Liu · Ze Zhao · Li Cui
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    ABSTRACT: This demonstration shows our versatile heterogeneous sensor networks testbed. This testbed supports high speed embedded WLAN node, medium speed IEEE802.15.4 node, wired computer and so on with powerful supervision platform. The unique features of the testbed are as follows: (1) Supporting heterogeneous sensor networks; (2) Owning powerful testbed nodes; (3) Emulating the interference and noise with the USRP2 replaying the real signal.
    Preview · Conference Paper · Jan 2010
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    ABSTRACT: Nowadays, the harmful blue-green algae blooms on lakes or streams threaten the daily life of millions of people in China. In this paper, we demonstrate the sensor network system we built on Lake Tai for the surveillance and cleanup of the algae blooms which is at work in Wuxi City, Jiangsu Province. We designed the sensor device and algorithm to monitor the algae bloom and estimate the bloom area. When the bloom area goes beyond the threshold, the salvaging boats are automatically dispatched to the scene to clean up the bloom for recycling utilization according to a mechanism in a scalable coordination fashion. The dispatching mechanism includes to consider the locations of salvaging boats, the number of available salvaging boats and the facility status in eight algae harvesting factories around the lake. The system also balances workloads of factories to achieve an overall high working efficiency. We develop a GIS-based management website for the end user to monitor the running of the whole system. All the sensing stations, the real time performance of the algae harvesting factory, the locations of salvaging boats and the automatically generated cleanup schedule are displayed in the map.
    Full-text · Conference Paper · Jan 2010
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    Shilong Lu · Xi Huang · Li Cui · Ze Zhao · Dong Li
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    ABSTRACT: The practical applications of wireless sensor networks require the sensor devices to be high in computation ability, low in power consumption, small in size, as well as competitive in cost. In addition, there are other particular attributes which require special consideration in sensor device design. These include, for example, the capabilities in protecting the embedded program from foreign intrusion and supporting efficient air-programming, which are very common requirements in many large-scale applications. In this paper, we describe the system architecture and design methodology of an ASCI-based sensor network device to meet those attributes for a class of applications. Compared with existing works, the unique features of the sensor device include: (1) a module-based extensible processor and co-processor cooperation architecture is designed with application-specific components to accelerate the signal collection, processing, and networking via hardware-software co-design to balance computation efficiency and design flexibility; (2) a program protection mechanism is developed based on un-resemble coder algorithm to protect the program data from being read out by system intruders so as to improve the security of the sensor device; (3) an air-programming component is proposed to enable an efficient remote programming which is a very common requirement in network deployment and maintenance. In this paper, we present the design, implementation, and evaluation of the prototype sensor device based on a general configurable FPGA platform for developing next-generation sensor devices. Initial results of the first version of prototype chip will also be introduced.
    Full-text · Article · Dec 2009 · IEEE Transactions on Consumer Electronics
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    ABSTRACT: In this paper, we describe a heterogeneous peer-to-peer network testbed, which is developed as part of a joint research project to investigate novel resource discovery and content distribution protocols in a heterogeneous wired/wireless environment. We describe the testbed requirements, the testbed architecture, the multi-functional wireless node, and the software architecture. We also describe some of the proposed protocols to be developed and tested on the testbed.
    Preview · Conference Paper · Jul 2009
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    ABSTRACT: Wireless peer-to-peer (P2P) networks have been widely studied in recent years. Testing and evaluating wireless P2P network protocols are challenging tasks because they require a powerful and flexible hardware platform and supervision interface. In this work, EZ270, a novel wireless node with multi-radio support is designed and developed. Based on EZ270, a general purpose wireless P2P network testbed with user-friendly supervision features is built. The functionality and effectiveness of the wireless nodes and of the testbed are demonstrated.
    No preview · Article · Jan 2009
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    Dong Li · Wei Liu · Ze Zhao · Li Cui
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    ABSTRACT: This paper presents an overview of our demonstration of a real application of a WSN system for relic protection applied in the Forbidden City of China. We briefly introduce the EasiNet hardware platform we have developed and the corresponding mesh-architecture of the system constructed. We present a sensor deployment optimization tool based on ant colony optimization technology (DT-ACO) to meet the requirements of network connectivity, sensing coverage and a minimized overall cost of the system. We describe a novel power-aware cross-layer scheme (PACS) to facilitate adjustable system lifetime and surveillance accuracy. We also show some detailed results of the application case.
    Full-text · Conference Paper · May 2008
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    ABSTRACT: There is a growing need for medical care resources when people pay more and more attention to their health conditions. The hospitals, however, can not satisfy all those ever-increasing requirements. There is hence a contradiction between the needs of the medical care and resource availability. A remote telemedical care system is a possible optimistic way towards solving this problem with the support of emerging new technologies. In this paper, we present the development of a wireless networked Chinese telemedicine system for remote pulse information monitoring, namely WNCTs, based on the principle of Chinese pulse diagnosis in Chinese medicine (CPD). The proposed wearing system may collect the pulse condition, analyze the information by data fusion and provide diagnostic results. The distinctive features of the proposed wireless system include: small in size, light in weight, multiple of type pulse detection and networked users' remote management. In this paper we provide the design and implementation of the wearing wireless networked Chinese telemedicine system. We also demonstrate the use of the system in pulse information retrieval. Our results indicate significant practical feasibility of the networked telemedicine system.
    No preview · Conference Paper · Apr 2008
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    ABSTRACT: This paper describes a wireless sensor network for mine safety monitoring. Based on the characteristics of underground mine gallery and the requirements for mine safety monitoring, we proposed a distributed heterogeneous hierarchical mine safety monitoring prototype system, namely HHMSM This system is capable of monitoring methane concentration, and locating miner. We proposed a novel overhearing-based adaptive data collecting scheme which exploits the redundancy and correlation of the sampling readings in both time and space to reduce traffic and control overhead with a well-bounded offset error for large-scale sensor networks. This mechanism is easy to implement and low-cost compared to other more theoretically based mechanisms such as Kalman filter. Experimental results show that HHMSM achieves better performance on flexibility, correctness, coverage, and lifetime compared with other existing wireless mine safety monitoring systems.
    Full-text · Conference Paper · Dec 2007
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    L.M. Ni · Li Cui · Qiong Luo · Hoilun Ngan · Ze Zhao
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    ABSTRACT: In March 2004, recognizing the importance of sensor networks, the Chinese Academy of Sciences and the Hong Kong University of Science and Technology launched a joint effort to investigate both fundamental and practical research issues in sensor networks. The goal of this research is to build lightweight optimized sensor systems on a massive scale, namely the BLOSSOMS project. The objective of this research project is to identify research issues at all levels from practical applications down to the design of sensor nodes. This paper reports the status of the project as of April 2005. First, other than making MOTE-compatible sensor nodes, this project has studied the hardware and software co-design and the associated "sensor node on a chip" technology with the aim to make sensor nodes small in size, light in weight, cheap in cost, and low in power consumption. Second, additional toolkits for simulation/emulation and evaluation of sensor networks have been developed to support research at different levels. Third, a number of applications have been investigated and implemented since the launch of this project, and this paper will address two of them. One is an embedded remote health care system based on wireless sensor network technologies to introduce a scalable wireless personal medical network around human's body. The other is a moving object counting system based on an ultrasonic sensor network, which can be used but not limited to crowd estimation and traffic monitoring and coordination.
    Full-text · Conference Paper · Sep 2005
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    Ze Zhao · Li Cui
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    ABSTRACT: An embedded remote health care system based on wireless sensor network technology was established. Firstly, a new system architecture was proposed which introduced a scalable wireless personal medical sensor network around human's body. Then the designs of several sensor node and the care base-station were presented. The wireless communication between the sensor nodes and the care base-station used IEEE 802.15.4/Zigbee standard whilst the care base-station and the remote central server was connected in one of the following ways, including computing network, GSM short messages and telephone modem. The system can be used for remote health care at home or in the hospitals.
    Preview · Article · Feb 2005 · Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference
  • Xi Huang · Ze Zhao · Li Cui
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    ABSTRACT: With the goal to make the wireless sensor network nodes small in size, light in weight, cheap in cost, as well as low in power consumption, projects have been carried out to study the hardware and software co-design and to develop sensor node SOC technology. We have proposed a general “sensor node on a chip” approach, namely EasiSOC, with two typical SOC architectures for different application areas. The first architecture of sensor node supports basic functionalities which performs relatively simple tasks with fixed routines. The second architecture of sensor node favors complex functionalities and advanced jobs. Current research progresses on the development of the first SOC structures are also introduced.
    No preview · Conference Paper · Jan 2005

Publication Stats

137 Citations
4.68 Total Impact Points

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Institutions

  • 2005-2013
    • Chinese Academy of Sciences
      • • Institute of Computing Technology
      • • Graduate School
      Peping, Beijing, China
  • 2009-2012
    • Technical Institute of Physics and Chemistry
      Peping, Beijing, China