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771.
Martin Vester-Christensen Sren G.H. Erbou Mads F. Hansen Eli V. Olsen Lars B. Christensen Marchen Hviid Bjarne K. Ersbll Rasmus Larsen 《Meat science》2009,81(4):699-704
This paper proposes the use of computed tomography (CT) as a reference method for estimating the lean meat percentage (LMP) of pig carcasses. The current reference is manual dissection which has a limited accuracy due to variability between butchers. A contextual Bayesian classification scheme is applied to classify volume elements of full body CT-scans of pig carcasses into three tissue types. A linear model describes the relation between voxels and the full weight of the half carcass, which can be determined more accurately than that of the lean meat content. Two hundred and ninety-nine half pig carcasses were weighed and CT-scanned. The explained variance of the model was R2=0.9994 with a root-mean-squared error of prediction of 83.6 g. Applying this method as a reference will ensure a more robust calibration of sensors for measuring the LMP, which is less prone to variation induced by manual intervention. 相似文献
772.
Balestrino A. Landi A. Ould-Zmirli M. Sani L. 《Industrial Electronics, IEEE Transactions on》2001,48(3):645-655
Accurate modeling of electrical drives for online testing is a relevant problem, because of their nonlinear behavior. Efficient modeling for simulation, performance evaluation, and testing must consider accurate as well as simple models. This paper proposes the application of auto-tune methods to identify equivalent Hammerstein models, where the nonlinear process is approximated by a static nonlinear element followed by a linear dynamic second or third-order model. The effectiveness of the presented procedure is first verified by simulation results, showing that Hammerstein models overcome the limitations inherent to small-signal linearizations. A standard implementation of such technique considers a relay adjustment for attempts in a heuristic way. In this paper, two innovations are proposed: the relay adjustment is automatically shifted and the method is applied for complex electric drives. Experimental results are shown in the case of a drive constituted by a DC/AC inverter supplying a single-phase induction motor and of a step-down chopper 相似文献
773.
Summary
A novel approach to a well-defined poly(2-hydroxyethyl methacrylate) [poly(HEMA)] and to its amphiphilic block copolymers
was developed. The selective living anionic polymerization of the methacryloyl group of the bifunctional monomer 2-vinyloxyethyl
methacrylate (VEMA) generated a functional polymer with a controlled molecular weight and a narrow molecular weight distribution
(Mw/Mn= 1.05–1.09). This polymer is very stable under normal conditions. Being soluble in the common organic solvents, its characterization
could be carried out easily. The unreacted vinyl groups in the side chains of the resulting polymer were further reacted with
hydrochloric acid. This acidolysis changed poly(VEMA) to a well-defined poly(HEMA). In addition, the anionic block copolymerization
of VEMA with styrene or methyl methacrylate also proceeded smoothly, generating the corresponding block copolymers. After
acidolysis, these copolymers were turned into amphiphilic block copolymers containing a hydrophilic poly(HEMA) block.
Received: 22 June 2001/Revised version: 15 August 2001/Accepted: 15 August 2001 相似文献
774.
In this paper we present a very practical ciphertext-only cryptanalysis of GSM (Global System for Mobile communications) encrypted
communication, and various active attacks on the GSM protocols. These attacks can even break into GSM networks that use “unbreakable”
ciphers. We first describe a ciphertext-only attack on A5/2 that requires a few dozen milliseconds of encrypted off-the-air
cellular conversation and finds the correct key in less than a second on a personal computer. We extend this attack to a (more
complex) ciphertext-only attack on A5/1. We then describe new (active) attacks on the protocols of networks that use A5/1,
A5/3, or even GPRS (General Packet Radio Service). These attacks exploit flaws in the GSM protocols, and they work whenever
the mobile phone supports a weak cipher such as A5/2. We emphasize that these attacks are on the protocols, and are thus applicable
whenever the cellular phone supports a weak cipher, for example, they are also applicable for attacking A5/3 networks using
the cryptanalysis of A5/1. Unlike previous attacks on GSM that require unrealistic information, like long known-plaintext
periods, our attacks are very practical and do not require any knowledge of the content of the conversation. Furthermore,
we describe how to fortify the attacks to withstand reception errors. As a result, our attacks allow attackers to tap conversations
and decrypt them either in real-time, or at any later time. We present several attack scenarios such as call hijacking, altering
of data messages and call theft.
An earlier version of this paper appears in Barkan et al. (Advances in Cryptology, Proceedings of Crypto 2003, Lecture Notes
in Computer Science, vol. 2729, pp. 600–616, 2003). 相似文献
775.
Afidah A. Rahim Emmanuel Rocca Jean Steinmetz M. Jain Kassim M. Sani Ibrahim Hasnah Osman 《Food chemistry》2008
Depolymerisation of mangrove Rhizophora apiculata bark extracts in the presence of phloroglucinol nucleophiles in ethanol was carried out. The flavan-3-ols and their phloroglucinol adducts were separated using reversed phase liquid chromatography (HPLC). The HPLC analysis of mangrove R. apiculata showed that catechin was the most common component of the flavanoid monomers. The antioxidant activities of these mangrove tannins were evaluated and compared with several commercial tannins by using reducing power, DPPH and ABTS assays with butylated hydroxytoluene, BHT and l-(+)-ascorbic acid as standards. All tannins had reducing power and percentage scavenging activities similar to the (+)-catechin and l-(+)-ascorbic acid standards. In the DPPH assay, >90% of the maximum scavenging activity was attained at 30 μg ml−1. Mangrove tannins had stronger antioxidant activity than the BHT standard in the DPPH assay. The results of the ABTS assay were correlated with the DPPH assay. Scavenging activity in the ABTS assay increased as the tannin concentration increased, up to a plateau at 50 μg ml−1. 相似文献
776.
Wolkers H van Bavel B Ericson I Skoglund E Kovacs KM Lydersen C 《The Science of the total environment》2006,370(1):70-79
Blubber samples from 17 adult, male walruses were sampled in eastern Svalbard and analyzed for chlorinated and brominated contaminants. A wide range of contaminants were detected, including PCBs (mean 2000; 95% range 1165-4005 ng/g lipid), DDE (mean 100: 95% range 50-310) ng/g lipid), chlordanes (mean 2500; 95% range 1347-5009) ng/g lipid, toxaphenes (mean 80; 95% range 51-132 ng/g lipid) and polybrominated diphenyl ethers (PBDEs) (mean 15 ng/g; 95% range 9-27 ng/g lipid). PCB and DDE levels were substantially lower than those of animals sampled 10 year earlier in this area, confirming a decreasing trend for these compounds in the Arctic. However, compared to other recently sampled marine mammals from Svalbard, walruses showed relatively high PCB and chlordane levels although they had lower levels of DDE, toxaphenes, and PBDEs, possibly due to species- and location-specific differences in exposure and metabolism. The range in contaminant levels found within the sample group was vast, despite the fact that the animals investigated were all adult males from the same location. The PCB pattern in highly contaminated animals was different from that in animals with low levels of contamination, with relatively more persistent PCBs in the highly contaminated group. This suggests that the more contaminated animals were feeding at higher trophic levels; possibly targeting seals in addition to mollusks as their prey. This suggestion was reinforced by the fatty acid profiles of the inner blubber layer of walruses with low versus high contaminant levels, which suggested different diets for the two groups. 相似文献
777.
778.
Karayiannis NB Mukherjee A Glover JR Ktonas PY Frost JD Hrachovy RA Mizrahi EM 《IEEE transactions on bio-medical engineering》2006,53(4):633-641
This paper presents an approach to detect epileptic seizure segments in the neonatal electroencephalogram (EEG) by characterizing the spectral features of the EEG waveform using a rule-based algorithm cascaded with a neural network. A rule-based algorithm screens out short segments of pseudosinusoidal EEG patterns as epileptic based on features in the power spectrum. The output of the rule-based algorithm is used to train and compare the performance of conventional feedforward neural networks and quantum neural networks. The results indicate that the trained neural networks, cascaded with the rule-based algorithm, improved the performance of the rule-based algorithm acting by itself. The evaluation of the proposed cascaded scheme for the detection of pseudosinusoidal seizure segments reveals its potential as a building block of the automated seizure detection system under development. 相似文献
779.
780.
Quantifying motion in video recordings of neonatal seizures by regularized optical flow methods. 总被引:1,自引:0,他引:1
Nicolaos B Karayiannis Bindu Varughese Guozhi Tao James D Frost Merrill S Wise Eli M Mizrahi 《IEEE transactions on image processing》2005,14(7):890-903
This paper presents the development of regularized optical flow computation methods and an evaluation of their performance in the extraction of quantitative motion information from video recordings of neonatal seizures. A general formulation of optical flow computation is presented and a mathematical framework for the development of practical tools for computing optical flow is outlined. In addition, this paper proposes an alternative formulation of the optical flow problem that relies on a discrete approximation of a family of quadratic functionals. These regularized optical flow computation methods are used to extract motion strength signals from video recordings of neonatal seizures. 相似文献