Scan-Along Polygonal Approximation for Data Compression of Electrocardiograms

Three fast and efficient "scan-along" algorithms for compressing digitized electrocardiographic data are described. These algorithms are "scan-along" in the sense that they produce the compressed data in real time as the electrocardiogram is generated. The algorithms are based on the minimum perimeter polygonal approximation for digitized curves. The approximation restricts the maximum error to be no greater than a specified value. Our algorithms achieve a compression ratio of ten on a database of 8000 5-beat abnormal electrocardiograms sampled at 250 Hz and a compression ratio of eleven on a database of 600 3-beat normal electrocardiograms (different from the preceding database) sampled at 500 Hz.     

Oxygen stoichiometry in the system (CaxSr1−x)FeO3−y. Its effect on crystallographic and thermodynamic properties

Oxygen-deficient perovskites of the system (Ca_xSr_1?x)FeO_3?y were prepared at high oxygen pressures up to 1900 atm (196 MPa), and measurements were made of their crystallographic and thermodynamic behavior. The a-spacing of perovskites expanded linearly with increasing oxygen deficiency for x = 0–0.4 and y = 0.01–0.19, and an eventual tetragonal distortion took place at the composition AFeO_2.82 (64% Fe⁴⁺). Thermogravimetric analysis of SrFeO_2.81 in vacuo revealed that oxygen atoms began to release from the perovskite lattice at 350°C. Thermodynamic analysis showed that oxygen deficiency had a linear relationship with the square root of the fugacity of oxygen gas, and the slope was $\text{?1.96 × 10}{}^{\mathrm{?3}}\text{atm}{}^{\mathrm{<mtext>?</mtext><mtext>1</mtext><mtext>2</mtext>}}\text{mol}{}^{\mathrm{?1}}$.     

Soft tissue differentiation using multiband signatures of high resolution ultrasonic transmission tomography

In this paper, we are interested in soft tissue differentiation by multiband images obtained from the High-Resolution Ultrasonic Transmission Tomography (HUTT) system using a spectral target detection method based on constrained energy minimization (CEM). We have developed a new tissue differentiation method (called "CEM filter bank") consisting of multiple CEM filters specially designed for detecting multiple types of tissues. Statistical inference on the output of the CEM filter bank is used to make a decision based on the maximum statistical significance rather than the magnitude of each CEM filter output. We test and validate this method through three-dimensional interphantom/intraphantom soft tissue classification where target profiles obtained from an arbitrary single slice are used for differentiation over multiple other tomographic slices. The performance of the proposed classifier is assessed using receiver operating characteristic analysis. We also apply our method to classify tiny structures inside a bovine kidney and sheep kidneys. Using the proposed method we can detect physical objects and biological tissues such as styrofoam balls, chicken tissue, calyces, and vessel-duct successfully.     

Mode propagation in optical nanowaveguides with dielectric cores and surrounding metal layers

The mode spectrum in an optical nanowaveguide consisting of a dielectric-core layer surrounded by two identical metal layers is investigated. A simple model based on mode matching to predict the properties of mode propagation in such optical nanowaveguides is proposed. It is shown that quasi-TM00 and quasi-TM10 modes supported by an optical microstrip line do not have a cutoff frequency, regardless of the size of the metal strips, the thickness of the dielectric slab, and the cross-sectional shape. The transverse size of the TM00 mode supported by a nanosized microstrip line was found to be approximately equal to the transverse dimension of the microstrip line. In closed rectangular and elliptical nanowaveguides, i.e., in which all dielectric surfaces are covered with metal films, the cross-sectional shape of the waveguide should be stretched along one side to produce propagation conditions for the fundamental mode.     

Effect of illumination in an integral imaging system with large depth of focus

We present the characteristics of integral imaging systems with large depth of focus (DOF) by use of two kinds of illumination: plane illumination and diffusing illumination. For each system, we perform ray analysis based on ray optics. To check the visual quality through optical experiments, we use an average image of observed images picked up at various positions within a large DOF. The synthesized elemental images for a three-dimensional (3-D) object with two character patterns were displayed in an optical system and its reconstruction experiments are performed. Experimental results show that use of diffusing illumination can improve visual quality of reconstruction 3-D images in depth-priority integral imaging.     

Best-Effort Patching for Multicast True VoD Service

A multicast Video-on-Demand (VoD) system allows clients to share a server stream by batching their requests, and hence, improves channel utilization. However, it is very difficult to equip such a VoD system with full support for interactive VCR functions which are important to a growing number of Internet applications. In order to eliminate service (admission) latency, patching was proposed to enable an existing multicast session to dynamically add new clients, and requests can be served without delay if patching channels are available. A true VoD (TVoD) service should support not only zero-delay client admission but also continuous VCR-like interactivity. However, the conventional patching is only suitable for admission control. We propose a new patching scheme, called Best-Effort Patching (BEP), that offers a TVoD service in terms of both request admission and VCR interactivity. Moreover, by using a novel dynamic merging algorithm, BEP significantly improves the efficiency of TVoD interactivity, especially for popular videos. We also model and evaluate the efficiency of the dynamic merging algorithm. It is shown that BEP outperforms the conventional TVoD interaction protocols.Huadong Ma received the B.S. degree in Mathematics from Henan Normal University in 1984, the M.S. degree in Computer Science from Shenyang Institute of Computing Technology, Chinese Academy of Science (CAS) in 1990 and the Ph.D. degree in Computer Science from Institute of Computing Technology, CAS, in 1995.He is a Professor with the School of Computer Science & Technology, Beijing University of Posts and Telecommunications, China. He visited UNU/IIST as research fellow in 1998 and 1999, respectively. From 1999 to 2000, he held a visiting position in the Real-Time Computing Laboratory in the Department of Electrical Engineering and Computer Science, The University of Michigan, Ann Arbor. His current research focuses on multimedia, networking, e-commerce and computergraphics, and he has published over 70papers and 3 books on these fields. He is member of IEEE and ACM.Kang G. Shin received the B.S. degree in Electronics Engineering from Seoul National University, Korea, in 1970, and both the M.S. and Ph.D. degrees in Electrical Engineering from Cornell University, Ithaca, New York in 1976 and 1978, respectively.He is the Kevin and Nancy OConnor Professor of Computer Scienceand Founding Director of the Real-Time Computing Laboratory in the Department of Electrical Engineering and Computer Science, The University of Michigan, Ann Arbor. His current research focuses on QoS-sensitive networking and computing as well as on embedded real-time OS, middleware and applications, all with emphasis on timeliness and dependability. He has supervised the completion of 49 Ph.D. theses, and authored/coauthored over 600 technical papers and numerous book chapters in the areas of distributed real-time computing and control, computer networking, fault-tolerant computing, and intelligent manufacturing. Dr. Shin is Fellow of IEEE and ACM, and member of the Korean Academy of Engineering.Weibiao Wu received the Ph.D. degree in statistics from the University of Michigan, Ann Arbor in 2001. He is currently an Assistant professor of statistics at the University of Chicago. His research interests include probabilistic network modelling and simulation, data-base compression, asymptotic theory and statistical inference of stochastic processes.     

Piezoelectric Properties of 0.2[Pb(Mg<Subscript>1/3</Subscript>Nb<Subscript>2/3</Subscript>)]-0.8[PbTiO<Subscript>3</Subscript>-PbZrO<Subscript>3</Subscript>] Ceramics Sintered at a Low Temperature with the Aid of Li<Subscript>2</Subscript>O

The dielectric and piezoelectric properties of 0.2Pb(Mg_1/3Nb_2/3)O₃-0.8Pb(Zr_0.475Ti_0.525)O₃ (abbr. as PMNZT) ceramics were measured. Extremely low sintering temperatures of 950^∘C using liquid-phase sintering aid of Li₂O is achieved which was very useful for multi-layered applications. X-ray study shows the splitting of rhombohedral (200) in pure PMNZT to (002) and (200) peaks in Li₂O doped samples. 10 times higher dielectric constant was achieved in Li₂O doped samples to compare to pure ones although the Curie temperature (T_c = 322^∘C) of Li₂O doped PMNZT ceramics was not changed. The value of k_p and k₃₃ increased up to 0.1 wt% of Li₂O and saturating thereafter.     

Three-parameter empirical isotherm model: its application to sorption onto organoclays

A new three-parameter empirical isotherm model (the Song isotherm model, hereinafter) is proposed. This model satisfies the Henry's law and the Freundlich isotherm model in the low and high concentration ranges, respectively. We applied this model to the single-solute sorption of 2-chloro-, 3-cyano-, and 4-nitrophenol from water to montmorillonites organically modified with either hexadecyltrimethylammonium (HDTMA) cation or both HDTMA and tetramethylammonium (TMA) dual cations. Sorption to organoclays (i.e., organically modified clays) modified with the long-hydrocarbon chain organic cations or the short- and long-hydrocarbon chain dual organic cations usually occurs by a partition mechanism. Sorption of polar organic compounds to organoclays, however, becomes nonlinear when the solution-phase concentration covered is more than 3 orders of magnitude. The three parameters contained in the presently proposed model could be estimated from the plot, log(q/c) versus log c. The partition coefficient in the Henry's law region (K) can be estimated from the ordinate value of the asymptote in the low concentration region, the Freundlich index (n) can be estimated from the slope of the asymptote in the high concentration region, and the parameter (beta) corresponding to the crossover point can be estimated from the intersection point of the two asymptotes. By performing nonlinear curve fitting to the raw data, q versus c, using the initial guesses estimated from the manipulated data, log-(q/c) versus log c, the optimum set of parameters could be determined without worrying much over the annoying local minima. The Song model was compared with other existing two- and three-parameter isotherm models. The Song model fitted our experimental data better than the Langmuir and Freundlich models and showed nearly the same goodness-of-fit as the Redlich-Peterson and dual-mode models. The obvious merit of the Song model is that it provides us with the partition coefficient in the Henry's law region. The organic carbon-normalized partition coefficients in the Henry's law region were found to be about 1 order of magnitude higher than the corresponding octanol-water partition coefficients, at least for the phenolic compounds covered in this study.