Efficient blind dereverberation and echo cancellation based on independent component analysis for actual acoustic signals

This letter presents a new algorithm for blind dereverberation and echo cancellation based on independent component analysis (ICA) for actual acoustic signals. We focus on frequency domain ICA (FD-ICA) because its computational cost and speed of learning convergence are sufficiently reasonable for practical applications such as hands-free speech recognition. In applying conventional FD-ICA as a preprocessing of automatic speech recognition in noisy environments, one of the most critical problems is how to cope with reverberations. To extract a clean signal from the reverberant observation, we model the separation process in the short-time Fourier transform domain and apply the multiple input/output inverse-filtering theorem (MINT) to the FD-ICA separation model. A naive implementation of this method is computationally expensive, because its time complexity is the second order of reverberation time. Therefore, the main issue in dereverberation is to reduce the high computational cost of ICA. In this letter, we reduce the computational complexity to the linear order of the reverberation time by using two techniques: (1) a separation model based on the independence of delayed observed signals with MINT and (2) spatial sphering for preprocessing. Experiments show that the computational cost grows in proportion to the linear order of the reverberation time and that our method improves the word correctness of automatic speech recognition by 10 to 20 points in a RT??= 670 ms reverberant environment.     

Novel screen technology for high‐contrast front‐projection display by controlling ambient‐light reflection

Abstract— One problem with front‐projection displays is that the screen contrast ratio decreases in bright ambient light. In this paper, we propose a new front‐projection display system that incorporates the control of reflection of ambient light in the screen design, providing a high contrast ratio even in a brightly lit room.     

Bending Behavior of Steel Pipe Girders Filled with Ultralight Mortar

Bending behavior of steel pipes filled with ultralight mortar was studied by bending tests using a steel pipe, steel pipes filled with ultralight mortar, and steel pipes filled with light aggregate concrete and normal concrete. The steel pipe model filled with normal concrete had 1.8 times higher bending strength than the steel pipe model. The bending behavior of the steel pipe filled model with ultralight mortar was not improved when the compressive strength of the ultralight mortar was less than 1 MPa. However, ductility was much improved when the compressive strength was over 5 MPa, and the ultimate steel strain was more than double of the steel pipe model. The strains of steel and concrete in all the models were proportional to the distance from the neutral axis until the steel plate yielded. A simple analytical method was proposed to calculate the bending moments of the ultralight mortar filled steel pipes. The calculated values agreed very well with the test results.     

船体结构极限海况下逐次崩溃行为研究

研究船体结构在极限海况下所遭受的载荷以及相应的结构逐次崩溃行为对于确保在航船舶的安全或是设计出合理安全可靠的船舶结构,具有重要的意义。在该文的研究中,首先用基于势流理论的三维奇点分布法进行作用于船体的载荷和船体运动的计算;将得到的随时间变化的载荷施加到整船结构模型上;然后运用MSC.Marc软件,考虑几何非线性和材料非线性,进行结构逐次崩溃分析,可得到结构的极限承载能力。在明确作用于船体的外力和结构的耐力以后,即可进行船体结构安全性评估;可通过加大崩溃区域的板厚或加强筋尺寸的方式来提高结构的承载能力,增加船体结构的安全度。     

Package Design of Ready-to-Drink Coffee Beverages Based on Food <Emphasis Type="Italic">Kansei</Emphasis> Model—Effects of Straw and Cognition Terms on Consumer’s Pleasantness

To design a consumer-oriented package that complements the taste and aroma of ready-to-drink chilled-cup coffee beverages by using the food kansei model, the effects of the diameter and the color of drinking straws as well as the cognition terms of coffee on consumer sensory characteristics and preferences were investigated. Variance and factor analyses of the sensory scores for chilled-cup coffee with milk and sugar using straws of different diameters, as rated by consumer panelists, extracted two perceived factors (F1, contribution ratio 36.5%, and F2, 28.6%). A two-dimensional plot of the average F1 and F2 scores of 123 panelists showed that the perceived characteristics of the same taste and aroma varied according to the straw diameter. An image investigation of different straw colors and another sensory evaluation using “black,” “brown,” and “green” straws were also performed. A principal component analysis of the image data revealed that the sensory characteristics of coffee with milk and sugar were imaged from the straw color. The second evaluation suggested that the images of straw colors affected the sensory characteristics. In addition, cluster and multiple-comparison analyses of Internet research data from consumers regarding the cognition terms for coffee exhibited three clusters representing the cognitive characteristics of terms by consumers and by developers and the differences of attractiveness degree on the cognition terms due to the consumers’ personal attributes. These studies provide useful information for the development of packages of chilled-cup coffee beverages.     

Mean–variance relationship of the number of flows in traffic aggregation and its application to traffic management

We consider the mean–variance relationship of the number of flows in traffic aggregation, where flows are divided into several groups randomly, based on a predefined flow aggregation index, such as source IP address. We first derive a quadratic relationship between the mean and the variance of the number of flows belonging to a randomly chosen traffic aggregation group. Note here that the result is applicable to sampled flows obtained through packet sampling. We then show that our analytically derived mean–variance relationship fits well those in actual packet trace data sets. Next, we present two applications of the mean–variance relationship to traffic management. One is an application to detecting network anomalies through monitoring a time series of traffic. Using the mean–variance relationship, we determine the traffic aggregation level in traffic monitoring so that it meets two predefined requirements on false positive and false negative ratios simultaneously. The other is an application to load balancing among network equipments that require per-flow management. We utilize the mean–variance relationship for estimating the processing capability required in each network equipment.     

A parallel method for large sparse generalized eigenvalue problems using a GridRPC system

In this paper we present a master–worker type parallel method for finding several eigenvalues and eigenvectors of a generalized eigenvalue problem , where A and B are large sparse matrices. A moment-based method that finds all of the eigenvalues that lie inside a given domain is used. In this method, a small matrix pencil that has only the desired eigenvalues is derived by solving large sparse systems of linear equations constructed from A and B. Since these equations can be solved independently, we solve them on remote servers in parallel. This approach is suitable for master–worker programming models. We have implemented and tested the proposed method in a grid environment using a grid RPC (remote procedure call) system called OmniRPC. The performance of the method on PC clusters that were used over a wide-area network was evaluated.     

Analysis of license inconsistency in large collections of open source projects

Free and open source software (FOSS) plays an important role in source code reuse practice. They usually come with one or more software licenses written in the header part of source files, stating the requirements and conditions which should be followed when been reused. Removing or modifying the license statement by re-distributors will result in the inconsistency of license with its ancestor, and may potentially cause license infringement. In this paper, we describe and categorize different types of license inconsistencies and propose a method to detect them. Then we applied this method to Debian 7.5 and a collection of 10,514 Java projects on GitHub and present the license inconsistency cases found in these systems. With a manual analysis, we summarized various reasons behind these license inconsistency cases, some of which imply potential license infringement and require attention from the developers. This analysis also exposes the difficulty to discover license infringements, highlighting the usefulness of finding and maintaining source code provenance.     

Amelioration of scopolamine induced cognitive dysfunction and oxidative stress by Inonotus obliquus - a medicinal mushroom

The present study was aimed to investigate the cognitive enhancing and anti-oxidant activities of Inonotus obliquus (Chaga) against scopolamine-induced experimental amnesia. Methanolic extract of Chaga (MEC) at 50 and 100 mg kg (-1)doses were administered orally for 7 days to amnesic mice. Learning and memory was assessed by passive avoidance task (PAT) and Morris water maze (MWM) test. Tacrine (THA, 10 mg kg (-1), orally (p.o)) used as a reference drug. To elucidate the mechanism of the cognitive enhancing activity of MEC, the activities of acetylcholinesterase (AChE), anti-oxidant enzymes, the levels of acetylcholine (ACh) and nitrite of mice brain homogenates were evaluated. MEC treatment for 7 days significantly improved the learning and memory as measured by PAT and MWM paradigms. Further, MEC significantly reduced the oxidative-nitritive stress, as evidenced by a decrease in malondialdehyde and nitrite levels and restored the glutathione and superoxide dismutase levels in a dose dependent manner. In addition, MEC treatment significantly decreased the AChE activity in both the salt and detergent-soluble fraction of brain homogenates. Further, treatment with MEC restored the levels of ACh as did THA. Thus, the significant cognitive enhancement observed in mice after MEC administration is closely related to higher brain anti-oxidant properties and inhibition of AChE activity. These findings stress the critical impact of Chaga, a medicinal mushroom, on the higher brain functions like learning and memory.     

Application of microbial genes to recalcitrant biomass utilization and environmental conservation

Recent papers concerning the application of microbial genes to recalcitrant biomass utilization and environmental conservation are reviewed. Microbial genes have been integrated and expressed in plants and microorganisms. When cellulose-degrading enzyme genes are expressed in rice plants, the transgenic plants exhibit swollen cell walls which increases the digestibility of rice straw in the rumen. When genes encoding aromatic compound-degrading enzymes are expressed in plants, it is expected that aromatic compounds contaminating soil would be degraded during the growth of the transgenic plants. The former transgenic plants are utilized as feed and the latter for phytoremediation. Dockerin and cohesin interactions occurring in the cellulase complex, cellulosome, are applied to the construction of artificial enzyme complexes and protein purification by expressing the genes in transformed bacteria and/or silkworms, respectively. In the case of the forced expression of bacterial genes encoding chitinase and/or hydrogenase in the wild-type bacteria, chitin degradation and hydrogen gas production in the transformed bacteria occur at much higher rates than in the wild type.