Two channel digital watermarking for music based on exponential time-spread echo kernel

To robustly and imperceptibly embed copyright information as a watermark into music clips, a two channel digital watermarking system based on the least significant bit (LSB) method and echo hiding (EH) with a new exponential time-spread echo kernel (ETEK) is proposed. By spreading the echo so that it seems like natural room reverberation, as well as the use of two channels to separately watermark by the LSB method and the EH method which have complementary characteristics, the system provides satisfactory sound quality and exhibits both efficient retrieval capacity and robustness against attacks. Experiments show that the proposed system retrieves watermarks with 100% accuracy for all clips and is almost imperceptible. With a set of 42 attacks supplied by the StirMark Benchmark for Audio (SMBA), the proposed system has an average robustness of 0.98 where the ideal value is 1.00, and higher than any conventional methods. With these results, the proposed system is shown to be possible for the application to music distribution over the Internet.     

Dependence of differential quantum efficiency on the confinementstructure in InGaAs/InGaAsP strained-layer multiple quantum-well lasers

An internal efficiency of 91% was obtained with In_0.7Ga _0.3As/InGaAsP strained-layer multiple quantum well (MQW) lasers emitting at a wavelength of 1.5 μm. The dependence of the reciprocal differential quantum efficiency on the length of the laser cavity shows that the absorption loss in the InGaAsP (λ=1.3 μm) confinement layer caused by carrier overflowing into the confinement layer reduces the internal efficiency     

Bronchogenic cysts and esophageal duplications: common origins and treatment

BACKGROUND/PURPOSE: Bronchogenic cysts and esophageal duplications are usually considered as separate foregut malformations. Yet, both are thought to arise from the same embryological event, division of the embryonic foregut, and they share common histological characteristics, often making their clinical differentiation difficult. METHODS: A retrospective review of the cases of 68 children treated at a single institution between 1937 and 1995 was performed. Thirty children were girls (44%) and 38 were boys (56%). Ages ranged from newborn to 24 years. Complete records were available in all children. Fourteen of these 68 children were asymptomatic. RESULTS: Respiratory (54%) or gastrointestinal (13%) symptoms were the most frequent presenting problems. The majority of children were treated by resection of the cyst (52 of 68; 76%), while 9 of 68 (13%) required lobectomy for intraparenchymal lesions. Three children underwent marsupialization, with all of these children requiring additional surgery for recurrent disease. Five children (5 of 68; 7%) had multiple cysts. The mortality rate from this series was 10% (7 of 68). Two deaths were caused by perioperative exsanguination, one related to bleeding from a cyst lined with gastric mucosa with subsequent ulceration and hemorrhage into the esophagus. Two deaths occurred secondary to septic complications, one from an esophageal leak and the other from an intraparenchymal abscess. Two deaths were caused by respiratory failure; one was unrelated (SIDS). The majority of cysts found on histological review were lined by respiratory epithelium or bronchial glands (51 of 68; 75%). Gastrointestinal epithelium was present in cysts of nine children, only two of which were clinically diagnosed as esophageal duplications. Twenty-one cases (21 of 68; 31%) were classified as esophageal duplications based on the intramural location of the cyst, yet 15 of 21 (71%) contained respiratory epithelium, substantiating the hypothesis of the common origin of these lesions. CONCLUSIONS: The histological similarity and anatomic proximity of the "bronchogenic cysts" and the intramural "esophageal duplications" supports their common origin. The possible complications of bleeding, ulceration, infection, and obstruction of the esophagus or airway, should generally lead to prompt resection.     

Max-plus algebra-based wavelet transforms and their FPGA implementation for image coding

In the present paper, we propose new image coding methods based on max-plus algebra-based wavelet transforms (MP-Wavelets). Max-plus algebra is an algebraic structure on the set of integers, endowed with maximum, minimum and standard addition as operations. The proposed wavelet decomposition schemes are novel classes of morphological wavelets which, in contrast to the existing approaches, involve only integers and only max, min and addition in their computation. Since they do not involve floating point calculations and multiplications, MP-Wavelets have a very low computational complexity and they are suitable for efficient hardware implementation. Through image coding experiments using 10,000 images extracted from low resolution web-crawled misc database, the characteristics of the proposed MP-Wavelets are presented. Furthermore, we show a computational complexity analysis to compare MP-Wavelets to one of the fastest wavelet transforms, the conventional Haar wavelet. The applicability of MP-Wavelets in video coding is also confirmed by image coding experiments using residual frames. Finally, the field programmable gate arrays (FPGA) implementation of MP-Wavelets is presented to confirm suitability of MP-Wavelets for hardware implementation.     

Flavour evaluation by multiple regression analysis of gas chromatographic patterns in soy sauce

The relationship between the gas chromatographic patterns and sensory tests on soy sauce aroma was investigated by modified multiple regression analysis. As a result good linear relationship between the two was observed on two different sample sets, with multiple correlation values of 0·949 and 0·966, respectively. This means that the result of the sensory test on a sample can be estimated from the gas chromatographic pattern. Next, the contributing proportions were calculated on all the peaks of a gas chromatographic pattern. These values mean the quantification of the importance of each peak for the whole aroma. The calculation of the contributing proportion leads to the identification and evaluation of the components responsible for the whole aroma and accordingly the technique obtained here offers a first step toward general studies of food flavour.     

Low threshold current density 1.3-μm strained-layer quantum-welllasers using n-type modulation doping

We have developed 1.3 μm n-type modulation-doped strained-layer quantum-well lasers. Modulation-doped lasers with long cavities (low threshold gain) exhibit much lower threshold current densities than conventional lasers with undoped barrier layers. The lowest threshold current density we obtained was 250 A/cm² for 1500 μm long lasers with five quantum wells. The estimated threshold current density for an infinite cavity length was 38 A/m²/well. This is the lowest value for InGaAsP-InGaAsP and InGaAs-InGaAsP quantum well lasers to our knowledge     

Influence of the carbon surface on cathode deposits in non-aqueous Li–O2 batteries

Cup-stacked carbon nanotubes (CSCNT) with different surface properties were used for the non-aqueous Li–O₂ battery cathodes, and then examined at high magnification to understand how the discharge products were deposited on the cathode. As-prepared CSCNT based cathode had many reactive edges consisting of truncated conical graphene layers. After discharge, discharge products with average particle size 50 nm covered a nanotube, resulting in a layer-like texture. On the other hand, a heat-treated CSCNT based cathode was composed of edges terminated by graphitization of several graphene layers. After discharge, the size of the products was almost the same but the products were agglomerated, forming a bulky morphology. It was, thus, found that the carbon surface structure was closely related with the morphology of the cathode deposits after discharge. First principles calculations also indicated that no terminated edges acted as preferential active sites in adsorbing and storing the reaction species. It was, therefore, concluded that the active edges of the carbon surface were indispensable for controlling the morphology of cathode deposits and improving the battery performance.     

First-order derivative-based super-resolution

A single fast super-resolution method based on first-order derivatives from neighbor pixels is proposed. The basic idea of the proposed method is to exploit a first-order derivatives component of six edge directions around a missing pixel, followed by back projection to reduce noise estimated by the difference between simulated and observed images. Using first-order derivatives as a feature, the proposed method is expected to have low computational complexity, and it can theoretically reduce blur, blocking, and ringing artifacts in edge areas compared to previous methods. Experiments were conducted using 900 natural grayscale images from the USC-SIPI Database. We evaluated the proposed and previous methods using peak signal-to-noise ratio, structural similarity, feature similarity, and computation time. Experimental results indicate that the proposed method clearly outperforms other state-of-the-art algorithms such as fast curvature-based interpolation.     

Optoelectronic integrated four-channel transmitter arrayincorporating AlGaAs/GaAs quantum-well lasers

A four-channel optoelectronic integrated transmitter array which is fabricated on a single GaAs substrate and operates at 834 nm is described. Each of the circuits incorporates a laser, a photodiode for laser power monitoring, and a laser driver circuit consisting of three GaAs field-effect transistors and a resistor. Laser threshold current of 15-21 mA, transmitter conversion efficiency of approximately 6 mW/V and high-speed operation at a bit rate of more than 1.5-Gb/s NRZ with allowable crosstalk have been demonstrated. A preliminary aging test of the lasers indicated that their stability is comparable to that of discrete devices. The results have demonstrated the feasibility of applying the transmitter array to optical components that process multichannel optical signals at high speed