Spectral derivative feature coding for hyperspectral signature analysis

This paper presents a new approach to hyperspectral signature analysis, called spectral derivative feature coding (SDFC). It is derived from texture features used in texture classification to dictate gradient changes among adjacent bands in characterizing spectral variations so as to improve better spectral discrimination and classification. In order to evaluate its performance, two known binary coding methods, spectral analysis manager (SPAM) and spectral feature-based binary coding (SFBC) are used to conduct comparative analysis. Experimental results demonstrate that the proposed SDFC performs more effectively in capturing spectral characteristics than do SPAM and SFBC.     

Comparison and improvement of tangent estimators on digital curves

Many contour-based applications rely on the estimation of the geometry of the shape, such as pattern recognition or classification methods. This paper proposes a comprehensive evaluation on the problem of tangent estimators on digital curves. The methods taken into account use different paradigms: approximation and digital geometry. In the former paradigm, methods based on polynomial fitting, smoothing and filtering are reviewed. In the latter case of digital geometry, we consider two methods that mainly rely on digital straight line recognition [J.-O. Lachaud, A. Vialard, F. de Vieilleville, Fast, accurate and convergent tangent estimation on digital contours, Image and Vision Computing 25(10) (2007) 1572-1587] and optimization [B. Kerautret, J.-O. Lachaud, Robust estimation of curvature along digital contours with global optimization, in: Proceedings of Discrete Geometry for Computer Imagery, Lyon, France, Lecture Notes in Computer Science, vol. 4992, Springer, Berlin, 2008]. The comparison takes into account objective criteria such as multi-grid convergence, average error, maximum error, isotropy and length estimation. Experiments underline that adaptive methods based on digital straight line recognition often propose a good trade-off between time and precision and that if precision is to be sought, non-adaptive methods can be easily transformed into adaptive methods to get more accurate estimations.     

Optimization methodology of dynamic data structures based on genetic algorithms for multimedia embedded systems

Modern multimedia application exhibit high resource utilization. In order to efficiently run this kind of applications in embedded systems, the dynamic memory subsystem needs to be optimized. A key role in this optimization is played by the dynamic data structures that reside in every real-life application. This paper presents a novel and automated way to optimize dynamic data structures. The search space is pruned using genetic algorithms that converge to the best multilayered data structure implementation for the targeted applications.     

Five decades of Computer-Aided Ship Design

This article will present a synoptical review of key developments in Computer-Aided Ship Design since its inception about five decades ago. Milestone events and major innovations will be identified in several categories of ship design application with the principal emphasis on the methodologies, the modeling and the integration of the ship design process. The discussion will address many specific subtasks of ship design on the common platform of a human-guided, computer-based decision process.     

A counterexample to “Generalized eigenvalue-based stability tests for 2-D linear systems: Necessary and sufficient conditions” by Fu, P., Chen, J., and S.I. Niculescu

We present a counterexample contradicting the equivalence of statements (i)-(ii) and (iii)-(v) of Theorem 1 of Fu, Chen, and Niculescu (2006).     

Blockage diagnostics for nuclear power plant pressure transmitter sensing lines

Blockages occur in pressure sensing lines in nuclear power plants due to solidification of boron, sludge, and accumulation of other contaminants. This paper investigates the impact of sensing line blockages on the pressure system transfer function based on an equivalent pi model. For both whole-length and localized blockage scenarios, the first resonant peak tends to shift toward a lower frequency while reducing the peak magnitude. Higher frequency resonant peaks may move to either higher or lower frequencies depending on the blockage type. The lower frequency peaks start to vanish when the impulse line cross-sectional area shrinks. Operational steam pressure noise data from a nuclear power plant are analyzed and are found to compare well to simulation results from the sensing line model. Utilization of the resonant peak frequency and peak interval deviations in the operational data power spectral density is introduced in this paper. This work can be employed to achieve predictive maintenance of sensing lines so that plant operation is not disturbed.     

A new compression based approach for reconfiguration overhead reduction in virtex based RTR systems

The advantage of RTR systems usually comes with some costs. The required time to map some areas of a program to an FPGA is considerable and affects the performance of RTR systems. Several methods have been developed to speed up the configuration process in these systems. Configuration compression can reduce the total number of write operations to load a configuration and it has been proven to be an efficient technique for dealing with the configuration overhead. In this paper, we have developed a new approach for reconfiguration overhead reduction in Virtex Based RTR Systems by using a compression technique based on Lempel-Ziv (LZ) algorithm. Since the order of the sequence of configuration frames affects the compression rate, we have proposed an algorithm based on Genetic Algorithm for finding the optimal configuration sequence of frames. The proposed algorithm will be applied to the input configuration file in a batch (offline) manner, and its time complexity is tolerable considering the overhead reduction obtained by having the optimal sequence of frames in run-time configuration decompression. Also, corresponding to our approach, a hardware model has been designed for configuration decompression.     

Writing power into online discussion

This article considers the way in which control of interaction emerges as a function of personal agency and external factors in a group of students engaged in online asynchronous text-based communication in a distance education program. It is structured around the argument that control is partly related to the power that individuals have to give effect to their wishes, but also acknowledges that this sense of agency is always in relation to the powers of others and more structural constraints. A picture emerges of the choices students make in deciding when to initiate discussion and respond to others, and about decisions concerning whose messages they would read and when. The impact of other students, of online groups, and instructors seems to play an important role in determining how participants participate in online interaction. Consideration of broader issues shows how the context in which students engage in interaction impacts the nature and extent of that interaction. The article concludes that being aware, and taking advantage of the socially grounded nature of online interaction provides the basis from which educators can act to ensure that interaction in online learning communities is enabling for the learning of all students.     

Why Napster matters to writing: Filesharing as a new ethic of digital delivery

This article discusses the Napster phenomenon and its cultural significance, traces some of the threads of the current “copyright crisis,” and connects these cultural and legal dynamics to show how the current filesharing context of digital environments pertains to issues affecting writing teachers. The article (1) urges writing teachers to view the Napster moment—and the writing practice at the center of it, filesharing—in terms of the rhetorical and economic dynamics of digital publishing and in the context of public battles about copyright and intellectual property and (2) argues that digital filesharing forms the basis for an emergent ethic of digital delivery, an ethic that should lead composition teachers to rethink pedagogical approaches and to revise plagiarism policies to recognize the value of filesharing and to acknowledge Fair Use as an ethic for digital composition.     

Detection method of the Kuroshio front using the satellite-derived chlorophyll-a images

Satellite-derived sea surface temperature (SST) has been providing high-resolution information of the oceanic front. However, in summer, increasing surface heating effects make SSTs uniform and the SST front disappears. The purpose of the present study is to examine applicability of satellite-derived surface chlorophyll-a (Chl-a) for detection of the Kuroshio front in the ocean south of Japan during the summer season.The Kuroshio surface front is formed between the Kuroshio water (KW) and the coastal water (CW) in the study area. Investigating accumulated in situ observations of SST and Chl-a, it is shown that the difference of Chl-a between KW and CW is increased in summer though that of SST becomes small. Using 76 pairs of cloud-free satellite-derived SST and Chl-a images with 0.01° spatial resolution, their seasonal variations are investigated through two-dimensional (2-D) histograms of Chl-a and SST. In summer, SST ranges from 25 to 30 °C and Chl-a ranges 0.03 to 0.4 mg/m³. Two peaks in the summer 2-D histogram correspond to wider KW and CW areas with rather uniform Chl-a and SST distributions. The peak values are extracted from the 2-D histograms and used to determine a threshold value dividing the KW and CW surface Chl-a during summer. It is found that the Chl-a concentration of 0.17 mg/m³ divides the extracted peaks into two groups, i.e., CW and KW except for a few peaks.The proposed Kuroshio-front detection method using the Chl-a images and the threshold value is examined using the satellite images and in situ data. The threshold contour superimposed in the summer Chl-a image distinctly separates the two representative waters in the ocean south of Japan. The front positions determined by the satellite-derived Chl-a, in situ SST, and in situ surface salinity transects along observation lines crossing the Kuroshio front agree with each other. Applying a traditional Kuroshio front index of temperature at 200 m depth, the capability of new Chl-a threshold in dividing two waters around the near-front area is quantitatively examined. Producing 74 match-ups of the satellite-derived Chl-a and 200-m temperature in the frontal zone, the dividing capability is evaluated quantitatively using the traditional Kuroshio-axis index. The detection capability of the proposed method is 82%, which can be considered high enough for practical applications.