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991.
Sun P Wu QH Weindling AM Finkelstein A Ibrahim K 《IEEE transactions on bio-medical engineering》2003,50(1):117-121
This paper describes an improved morphological approach to remove baseline wander from neonatal electrocardiogram (ECG) signals, with particular emphasis on preserving the ST segment of the original signal. The algorithm consists of two stages of morphological processing. First, the QRS complex and impulsive noise component due to skeletal muscle contractions etc., are detected and removed from the input signal. Second, the corrected QT interval (QTc) and RR interval are used to determine a structuring element. With this structuring element, the same morphological operation as in the first stage is then applied to the QRS-removed signal to obtain and remove the baseline wander. The performance of the algorithm is evaluated with simulated and real ECGs. Compared with an existing morphological method, there is a substantial improvement, especially in reducing distortion of the baseline waveform within the PR and QT intervals. 相似文献
992.
Atabay HI Aydin F Houf K Sahin M Vandamme P 《International journal of food microbiology》2003,81(1):21-28
In this study, the prevalence of Arcobacter spp. on chicken carcasses sold in various retail markets in Turkey was investigated. The isolates were characterized and identified using various phenotypic and molecular tests. The membrane filtration technique employing 0.45-microm pore size membrane filters laid onto a nonselective blood agar was used after enrichment in Oxoid Arcobacter Enrichment Broth (AEB) to examine a total of 75 chicken carcasses (44 fresh and 31 frozen). Species level identification was performed using SDS-PAGE of whole-cell proteins and a recently developed multiplex-PCR assay. All isolates were identified as Arcobacter butzleri. Of the 44 fresh chicken carcasses examined, 42 (95%) were positive for A. butzleri. A. butzleri was also recovered from seven (23%) of the 31 frozen carcasses examined. 相似文献
993.
Concurrency control and recovery for balanced B-link trees 总被引:1,自引:0,他引:1
Ibrahim Jaluta Seppo Sippu Eljas Soisalon-Soininen 《The VLDB Journal The International Journal on Very Large Data Bases》2005,14(2):257-277
In this paper we present new concurrent and recoverable B-link-tree algorithms. Unlike previous algorithms, ours maintain the balance of the B-link tree at all times, so that a logarithmic time bound for a search or an update operation is guaranteed under arbitrary sequences of record insertions and deletions. A database transaction can contain any number of operations of the form fetch the first (or next) matching record, insert a record, or delete a record, where database records are identified by their primary keys. Repeatable-read-level isolation for transactions is guaranteed by key-range locking. The algorithms apply the write-ahead logging (WAL) protocol and the steal and no-force buffering policies for index and data pages. Record inserts and deletes on leaf pages of a B-link tree are logged using physiological redo-undo log records. Each structure modification such as a page split or merge is made an atomic action by keeping the pages involved in the modification latched for the (short) duration of the modification and the logging of that modification; at most two B-link-tree pages are kept X-latched at a time. Each structure modification brings the B-link tree into a structurally consistent and balanced state whenever the tree was structurally consistent and balanced initially. Each structure modification is logged using a single physiological redo-only log record. Thus, a structure modification will never be undone even if the transaction that gave rise to it eventually aborts. In restart recovery, the redo pass of our ARIES-based recovery protocol will always produce a structurally consistent and balanced B-link tree, on which the database updates by backward-rolling transactions can always be undone logically, when a physical (page-oriented) undo is no longer possible.Received: 8 October 2003, Accepted: 19 February 2004, Published online: 14 September 2004Edited by: B. Seeger 相似文献
994.
Ibrahim TS Kangarlu A Chakeress DW 《IEEE transactions on bio-medical engineering》2005,52(7):1278-1284
In this paper, two TEM resonators were evaluated experimentally and numerically at 8 tesla (T) (340 MHz for 1H imaging). The coils were constructed to be 21.2-cm long (standard) and 11-cm long (a proposed less claustrophobic design). The experimental evaluation was done on a single cadaver using an ultra high field, 8 T, whole-body magnet. The numerical modeling was performed using an in-house finite difference time domain packagethat treats the coil and the load (anatomically detailed human head model) as a single system. The coils were tested with quadrature excitation at different coil alignment positions with respect to human head. For head imaging at 8 T, the overall numerical and experimental results demonstrated that when compared to the longer coil, the shorter coil provides superior signal-to-noise ratio, coil sensitivity, and excite field in the biological regions that lie within both of the coils' structures. A study of the RF (excite/receive fields) homogeneity showed variations in the performance of both coils that are mostly dependant on the region of interest and the position of coil with respect to the head. As such, depending on the application, the shorter coil could be effectively utilized. 相似文献
995.
p-methoxyphenoxy and p-chlorophenoxy group containing methacrylate based monomer 2-(p-methoxyphenoxy)-2-oxo-ethyl methacrylate (pMPOEMA) and 2-(p-chlorophenoxy)-2-oxo-ethyl methacrylate (p-ClPOEMA) were synthesized by reacting p-methoxyphenyl chloroacetate (pMPClAcO) and p-chlorophenyl chloroacetate (pClPClAcO) with sodium methacrylate in acetonitrile respectively. (pMPClAcO) and (pClPClAcO) were prepared by reacting p-methoxyphenol and p-chlorophenol dissolved in benzene with chloroacetylchloride. The free-radical-initiated copolymerization of (pMPOEMA) and (pClPOEMA) with acrylonitrile (AN) were carried out in 1,4-dioxane solution at 65 ○C using 2,2′-azobisisobutyronitrile (AIBN) as an initiator with different monomer-to-monomer ratios in the feed. The monomers and copolymers were characterized by FTIR, 1H- and 13C-NMR spectral studies. The copolymer compositions were evaluated by nitrogen content in polymers. The reactivity ratios of the monomers were determined by the application of Fineman–Ross and Kelen–Tüdös methods. The analysis of reactivity ratios revealed that pMPOEMA and pClPOEMA are more reactive than AN, and copolymers formed are statistically in nature. The molecular weights (
and
) and polydispersity index of the polymers were determined using gel permation chromagtography. Thermogravimetric analysis of the polymers reveal that the thermal stability of the copolymers increases with an increase in the mole fraction of AN in the copolymers. Glass transition temperatures of the copolymers were found to decrease with an increase in the mole fraction of AN in the copolymers. 相似文献
996.
An analog Gaussian frequency shift keying (GFSK) modulator designed in 0.35-/spl mu/m CMOS consumes 600 /spl mu/A from a 3-V supply and realizes an analog implementation of the FM differential equation. The modulator operates at baseband and is intended for use in a direct-conversion Bluetooth transmitter. It achieves a frequency deviation of 160 kHz with better than /spl plusmn/3% accuracy. The modulator implements an amplitude control loop to achieve a well-defined output swing. The total output harmonic distortion is less than 1%. 相似文献
997.
Dogan Ibrahim 《Microprocessors and Microsystems》1980,4(3):95-100
The first article described the basic design principles of the data and control section of a bit-slice computer. We shall now consider the design of the remaining subsystems of the computer. 相似文献
998.
Levent Sezer Ibrahim Zeid 《International journal for numerical methods in engineering》1991,32(7):1441-1483
Automation of finite element mesh generation holds great benefits for mechanical product development and analysis. In addition to freeing engineers from mundane tasks, automation of mesh generation reduces product cycle design and eliminates human-related errors. Most of the existing mesh generation methods are either semi-automatic or require specific topological information. A fully automatic free-form mesh generation method is described in this paper to alleviate some of these problems. The method is capable of meshing singly or multiply connected convex/concave planar regions. These regions can be viewed as crosssectional areas of 2 1/2 D objects analysed as plane stress, plane strain or axisymmetric stress problems. In addition to being fully automatic, the method produces quadrilateral or triangular elements with aspect rations near one. Moreover, it does not require any topological constraints on the regions to be meshed; i.e. it provides free-form mesh generation. The input to the method includes the region's boundary curves, the element size and the mesh grading information. The method begins by decomposing the planar region to be meshed into convex subregions. Each subregion is meshed by first generating nodes on its boundaries using the input element size. The boundary nodes are then offset to mesh the subregion. The resulting meshes are merged together to form the final mesh. The paper describes the method in detail, algorithms developed to implement it and sample numerical examples. Results on parametric studies of the method performance are also discussed. 相似文献
999.
A novel unidirectional pipelined serial/parallel multiplier (PSPM) is presented. This design has halved the initial delay and reduces the number of latches by 10% of the conventional structure. An area-time criteria is used to compare the new architecture with the old PSPM.<> 相似文献
1000.
A simplified explanation is given for negative resistance in a semiconductor containing deep-lying donor and acceptor levels. A simple equation is derived for the breakover voltage and is verified by experimental studies of single and double-injection currents in gold-doped silicon. 相似文献