Clustering Algorithm is a kind of key technique used to reduce energy consumption, which can increase
network scalability and lifetime. The main goal of this research is concerning protocols to contain in-motion sensor
nodes in large-scale topologies, and constitute a fleet wireless sensor network which can assistant in-flight
localization and alignment for carrier-based aircraft. In this paper, we abstract network model according to specific
conditions of F-WSN, and select performance indicators to evaluate it. A distributed multiple-weight data gathering
and aggregation protocol (DMDG) is proposed, which contains all-sided active clustering scheme and realizes
long-range realtime communication by tacical data link under a TDMA/CSMA channel sharing mechanism. An
analytical paradigm facilitating the most appropriate choice of the next relay is proposed. Experimental results have
shown that DMDG scheme can balance the energy consumption and extend the network lifetime notably, outperform
LEACH, PEACH, and DEEC in terms of network lifetime and coverage rate, especially in sparse node density or
In this paper, a simulation method for lens design is presented considering the aberration effect.
Traditionally, most optical path calculation algorithms are based on aberration theory and result in approximation.
For eliminating this problem and avoiding the limitations from aberration theory, this paper considers paraxial rays
and others as the same to trace their paths. For checking out the tracing algorithm, a programs based on OpenGL is
created in three-dimension and with real time controlling. Another program is implemented to show how the digital
photos should be changed when using different lens parameters.
We carried out an entropy study on the DNS query traffic from the Internet to the top domain DNS server
in a university campus network through January 1st to March 31st, 2009. The obtained results are: (1) We observed
a difference for the entropy changes among the total-, the A-, and the PTR resource records (RRs) based DNS query
traffic from the Internet through January 17th to February 1st, 2009. (2) We found the large NS RR based DNS
query traffic including only a keyword ”.” in the total inbound DNS query traffic. (3) We also found that the unique
source IP address based PTR DNS traffic entropy slightly increased, while the unique DNS query keywords based one
drastically decreased in March 9th, 2009. We found a specific IP host which was an already-hijacked classical Linux
PC that carried out the SSH dictionary attack to the Internet sites in March 9th, 2009. From these results,we can detect
the unusual inbound NS RR based DNS traffic and the outbound SSH dictionary attacks by only watching DNS query
traffic from the Internet.
Robot audition system can greatly improve the adaptability of mobile robots especially in the case of robot
vision system can’t work effectively. So an acoustic localization system using microphone array for mobile robot is
proposed in this paper. In order to localize the sound source target, the microphone array used in the system consists
of four microphones which were placed respectively on the vertexes of regular tetrahedron because of sound’s
omni-directional property. According to the plane wave model of sound’s propagation and the spherical wave model
of sound’s propagation, two different localization algorithms based on time delay of arrival are developed in this
paper. The hardware and software of the experiment platform are also introduced in this paper. The experimental
results show that the acoustic localization system can make the mobile robot rapidly and accurately reach the location
of the sound source target.