Jinfeng Dou

Balance transmission mechanism in underwater acoustic sensor networks

With the rapid development of underwater acoustic modem technology, underwater acoustic sensor networks (UWASNs) have more applications in long-term monitoring of the deployment area. In the underwater environment, the sensors are costly with limited energy. And acoustic communication medium poses new challenges, including high path loss, low bandwidth, and high energy consumption. Therefore, designing transmission mechanism to decrease energy consumption and to optimize the lifetime of UWASN becomes a significant task. This paper proposes a balance transmission mechanism, and divides the data transmission process into two phases. In the routing set-up phase, an efficient routing algorithm based on the optimum transmission distance is present to optimize the energy consumption of the UWASN. And then, a data balance transmission algorithm is introduced in the stable data transmission phase. The algorithm determines one-hop or multihop data transmission of the node to underwater sink according to the current energy level of adjacent nodes. Furthermore, detailed theoretical analysis evaluates the optimum energy levels in the UWASNs with different scales. The simulation results prove the efficiency of the BTM.

ELT: Energy-Level-Based Hybrid Transmission in Underwater Sensor Acoustic Networks

Lifetime prolonging is one significant research issue in underwater acoustic sensor networks (UASNs). First this paper analyzes the relationship between the receiving energy consumption and the transmission energy consumption in the acoustic communication of UASNs. The routing tree is built up on the factor of optimal transmission range. Then a hybrid data transmission mechanism based on energy level is proposed to balance energy consumption. The mechanism combines one-hop and multi-hop data transmission to underwater sink considering the current energy level of adjacent nodes. An optimal classification number of energy level has been evaluated through theoretical analysis. Our design will help prolong the lifetime of whole UASN. The simulation results of UASNs lifetime and the energy consumption of sensor nodes have proved the efficiency of the Energy-Level-based hybrid Transmission (ELT) mechanism.

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.

Lifetime Prolonging Algorithms for Wireless Sensor Networks

In the wireless sensor networks, prolonging network lifetime is an important aim. Unbalanced energy consumption influences greatly the network lifetime. Therefore, it introduces hybrid transmission mechanism for cell-based wireless sensor network. The sensor node forwards data either by one-hop direct transmission or by multiple small hops. This mechanism focuses on a novel transmission probabilities finding algorithm. The algorithm can obtained the hybrid transmission probabilities of each slice to even out the energy consumption efficiently. Furthermore, lateral length optimizing method is developed for each cell. Simulations show the mechanism can prolong the network lifetime more efficiently comparing with other schemes.

Energy-efficient uniform clustering algorithm for wireless sensor networks

The efficient subdivision of a sensor network into uniform clusters of physically close nodes is an important building block in the design of efficient upper layer network functions such as routing, broadcast, data aggregation, and query processing. This paper analyzes a low energy adaptive clustering hierarchy (LEACH) in terms of the optimum number of clusters and demonstrates through simulation that the optimum number calculated are not suitable for sensor networks including large number of nodes or covering large area. Based on the analysis results, we give a new formula of calculating the optimum number of clusters on an improved data gathering model. To decrease the energy dissipation further, we develop a new efficient uniform clustering algorithm in ad-hoc sensor networks. Simulation results show that it achieves fairly uniform cluster-head distribution across the network.

Data Aggregation Rate Assumption for Wireless Sensors

The concept of data aggregation rate (DAR) is introduced to denote the compressing capability of a sensor node in the sensor networks. The traditional assumption conditions about sensor capabilities include perfect data aggregation (PDA) and not using data aggregation (NDA). DAR breaks through the traditional assumption conditions and presents a new assumption. Furthermore, the traditional assumptions can be considered as two special cases of the new assumption. Then, a relationship among DAR, lifetime and the amount of the signal received at the base station is given. Simulations show that the proposed assumption has a more efficient tradeoff between the number of data signals received and the network lifetime by the comparison.

Design of Artistic Classroom in Operating System Course

This paper depicts the design of the artistic classroom in the Course of computer Operating System (COS). Considering the characteristics of COS and the valuable experience of other famous teachers teaching experience, it analyzes the methods to create an attractive classroom based on the work experience. These methods have been applied to the teaching activities of COS, and several teaching design cases have been shared with other teachers. With the satisfied results and pleased feedback, this design does facilitate teachers and students in teaching, learning and application.

Improving Teaching Quality through the Conversion of Research Production

The training student’s application practice ability plays an important role in improving the quality of culture of computer special field student. In this paper, the process of converting the scientific research achievement of test system software development to teaching cases and the production of related experimental hardware devices are proposed. We can see from the teaching effectiveness that the interest in learning was excited by teaching cases which were closed to the practical application as so as the advancement of the comprehensive development ability of student.

ATA: adaptive transmission algorithms for prolonging lifetime in underwater sensor networks

The severe energy constraints of sensors and the unique characteristics of underwater sensor networks (UWSNs) present major challenges for the long-term monitoring applications. This paper proposes two novel adaptive transmission algorithms for UWSNs to prolong lifetime. When a message becomes available for propagation at a node, the node will propagate data by multi-hop or one-hop to the master node according to the hybrid of its residual energy and a threshold. The threshold is predetermined by the master node and is not changed midway. This study applies the approaches to star topology for various combinations of internode distance, frequency and the number of nodes in a prototype hallow UWSNs. Simulation experiments show that the schemes can prolong the lifetime comparing with the existing schemes of UWSNs.

Probability and suboptimal distance based lifetime prolong algorithms for wireless sensor networks

In the wireless sensor networks, prolonging network lifetime is an important aim. Unbalanced energy consumption influences the network lifetime greatly. First this study proposes probability based energy balancing algorithms. A hybrid transmission mechanism is introduced. The sensor node forwards data either by one-hop direct transmission or by multiple small hops with the probability. This study focuses on a novel transmission probabilities finding algorithm, in which the transmission probabilities for each slice are obtained to even out the energy consumption efficiently. Then, a sub-optimal distance based energy optimization algorithm is proposed to optimize energy consumption. It optimizes the slice width and selects relays by sub-optimal distance near the optimum radio range, saves more energy and improves the network lifetime efficiently. Our claims are well supported by comparative simulations.