Zhongwen Guo

Research of marine sensor web based on SOA and EDA

A great deal of ocean sensor observation data exists, for a wide range of marine disciplines, derived from in situ and remote observing platforms, in real-time, near-real-time and delayed mode. Ocean monitoring is routinely completed using sensors and instruments. Standardization is the key requirement for exchanging information about ocean sensors and sensor data and for comparing and combining information from different sensor networks. One or more sensors are often physically integrated into a single ocean ‘instrument’ device, which often brings in many challenges related to diverse sensor data formats, parameters units, different spatiotemporal resolution, application domains, data quality and sensors protocols. To face these challenges requires the standardization efforts aiming at facilitating the so-called Sensor Web, which making it easy to provide public access to sensor data and metadata information. In this paper, a Marine Sensor Web, based on SOA and EDA and integrating the MBARI’s PUCK protocol, IEEE 1451 and OGC SWE 2.0, is illustrated with a five-layer architecture. The Web Service layer and Event Process layer are illustrated in detail with an actual example. The demo study has demonstrated that a standard-based system can be built to access sensors and marine instruments distributed globally using common Web browsers for monitoring the environment and oceanic conditions besides marine sensor data on the Web, this framework of Marine Sensor Web can also play an important role in many other domains’ information integration.

Using Sensor Web to Sharing Data of Ocean Observing Systems

Based on the OGC New Generation SWE-Sensor Web 2.0 and other related projects implementation, this paper gives the four layers architecture of ocean sensor web and details of every layer. The Information Model layer and Interface Model layer are illustrated in detail by the actual example. At last an ocean sensor prototype system sharing data is presented based on the real ocean sensor observing system of 20 nodes wireless sensor network, which is the middleware between ocean sensors and ocean sensor observing data usage. Though the SWE 2.0 standards can be applied in complex scenarios, most of the available deployments are providing data from in-situ sensors.

DPOI: Distributed software system development platform for ocean information service

Ocean information management is of great importance as it has been employed in many areas of ocean science and technology. However, the developments of Ocean Information Systems (OISs) often suffer from low efficiency because of repetitive work and continuous modifications caused by dynamic requirements. In this paper, the basic requirements of OISs are analyzed first, and then a novel platform DPOI is proposed to improve development efficiency and enhance software quality of OISs by providing off-the-shelf resources. In the platform, the OIS is decomposed hierarchically into a set of modules, which can be reused in different system developments. These modules include the acquisition middleware and data loader that collect data from instruments and files respectively, the database that stores data consistently, the components that support fast application generation, the web services that make the data from distributed sources syntactical by use of predefined schemas and the configuration toolkit that enables software customization. With the assistance of the development platform, the software development needs no programming and the development procedure is thus accelerated greatly. We have applied the development platform in practical developments and evaluated its efficiency in several development practices and different development approaches. The results show that DPOI significantly improves development efficiency and software quality.

A long-term temperature and depth logger for ocean mooring system

Temperature, depth and conductivity (CTD) are the most essential physical properties of sea water. CTD instrument is one of the most efficient approaches for collecting the accurate ocean information. However, traditional CTD instruments are not best suited for applications that require high resolution data by a large number of sensors because of their large size and high cost. This paper describes the design of a compact, high-accuracy, and low-cost temperature and depth (TD) logger for ocean mooring system. The noise floor of the TD logger was evaluated in lab for determining the logger measurement resolution. A specific calibration method was implemented for pressure transducer calibration to eliminate the thermal affect. The initial temperature accuracy of TD logger is ±0.002°C and the pressure accuracy is ±0.05% of full scale. The effective resolution is 0.0001°C and 0.001% full scale for temperature and pressure measurement, respectively. A 150-day off-shore experiment yielded 0.41 million temperature and pressure measurements that confirmed the stability of TD logger measurement. The correlation analysis revealed a maximum deviation of 0.2°C and 0.8m compared to independent measurements.

The automatic stitching for underwater close-range images from ROV

In this paper, A method giving consideration to both acquiring interrelated clear underwater-image and realizing fully automatic stitching for that is proposed. The rapidity and precision of stitching for multi-image, especially the underwater-image is influenced by the low resolution and fuzzy target etc. In allusion to influencing factors, a new and reliable approach effective in above two problems is developed. The underwater close-range images are captured from the camera carried on a novel ROV. Considering the changing of angle and lighting conditions etc in underwater, an approach using invariant features, which is insensitive to zoom, orientation and illumination of the input images is used to achieve automatic stitching.

Component-based development framework for ocean information system

Software developments of Ocean Information Systems (OISs) have suffered from low efficiency and poor quality due to the absence of powerful software development models and methods. In this paper, the component-based development framework is proposed to facilitate OIS software developments. The framework consists of unified data model (UDM) and component development model (CDM). In the UDM, the classification of ocean data is described and the structure of each type of data is unified. In the CDM, similar functions required in ocean information management are encapsulated into a component, which is designed, implemented and tested independently. All the components form the component repository. The development process is then turned into selecting the appropriate components from the component repository and assembling them into a whole. Hence the development efficiency is improved greatly due to the shortened development and debugging time. The development models are proved to be feasible and effective by applying it to the development of prototype systems.

A development framework for ocean environmental information service application

Ocean environmental information service applications are widely adopted to assist collection, storage and distribution of ocean environmental data. Unfortunately, a reference framework rarely rules the development of those systems, leading to poor software quality and bringing many troubles in the process of maintenance and integration. This paper presents a common development framework which supports ocean environment in-situ data and model outputs integration and appliance. The framework presented consists of flexible database architecture, scalable ocean data loader, data cooperation-service, reusable component factory, client-based system configuration and system management. Practical project is carried on to validate the framework and the result shows its availability.