Pyramid collaborative filtering technique for an intelligent autonomous guide agent

This article presents an autonomous guide agent that can observe a community of learners on the web, interpret the learners' inputs, and then assess their sharing. The goal of this agent is to find a reliable helper (tutor or other learner) to assist a learner in solving his task. Despite the growing number of Internet users, the ability to find helpers is still a challenging and important problem. Although helpers could have much useful information about courses to be taught, many learners fail to understand their presentations. For that, the agent must be able to deal autonomously with the following challenges: Do helpers have information that the learners need? Will helpers present information that learners can understand? And can we guarantee that these helpers will collaborate effectively with learners? We have developed a new filtering framework, called a pyramid collaborative filtering model, to whittle the number of helpers down to just one. We have proposed four levels for the pyramid. Moving from one level to another depends on three filtering techniques: domain model filtering, user model filtering, and credibility model filtering. A new technique is filtering according to helpers' credibilities. Our experiments show that this method greatly improves filtering effectiveness. © 2007 Wiley Periodicals, Inc. Int J Int Syst 22: 1065–1082, 2007.     

Electrical conductivity of concrete containing silica fume

The influence of silica fume on concrete properties represents an important technical research. In general, silica fume tends to improve both mechanical characteristics and durability of concrete. Thus the electrical properties of concrete containing silica fume can be studied to clarify its physical performance during hydration. The electrical conductivity of neat cement, mortar and concrete pastes was measured during setting and hardening. The ordinary Portland cement was partially replaced by different amounts of silica fume by weight. The changes in the electrical conductivity were reported during setting and hardening after gauging with water. The results of this study showed that the electrical conductivity can be used as an indication for the setting characteristics as well as the structural changes of the hardened pastes made with and without silica fume.     

Decoupled direct control for PWM inverter-fed induction motor drives

A new direct torque and stator flux control method is presented for pulsewidth modulation (PWM) inverter-fed induction motors. This new strategy, called decoupled direct control (DDC), is based on a decoupling matrix that allows for the separate control of the stator flux and the torque. This method is compared to the well-known direct field-oriented control (FOC) and stator flux vector control (SFVC) methods. Two DDC-based methods are presented. The first determines the stator voltage vector such that the torque and the flux track their respective reference trajectories in one sampling time. The second sets separately the dynamic behavior of the torque and stator flux errors by the use of proportional-plus integral (PI)-type controllers. These methods take into account the full motor dynamics without the need of a coordinate transformation and reduce significantly computation requirements compared to FOC and SFVC. The two proposed strategies have been implemented experimentally and comparisons with FOC and SFVC were carried out. The obtained results show the effectiveness of the proposed PI-DDC strategy.     

Comparison between nonconforming movement methods

In this work, we compare two nonconforming movement techniques: the mortar element method and the Lagrange multipliers. We present a unified formulation that can be easily used for electrical machines analysis. The anti-periodicity conditions as well as the use of high-order interface are discussed. The obtained linear systems are compared and results are shown for a permanent magnet machine.     

Modified Spherical Wave Functions With Anisotropy Ratio: Application to the Analysis of Scattering by Multilayered Anisotropic Shells

We describe a novel and rigorous vector eigenfunction expansion of electric-type Green's dyadics for radially multi- layered uniaxial anisotropic media in terms of the modified spherical vector wave functions, which can take into account the effects of anisotropy ratio systematically. In each layer, the material constitutions e and epsiv macrmu macr are tensors and distribution of sources is arbitrary. Both the unbounded and scattering dyadic Green's functions (DGFs) for rotationally uniaxial anisotropic media are derived in spherical coordinates (r, thetas, phi). The coefficients of scattering DGFs, based on the coupling recursive algorithm satisfied by the coefficient matrix, are derived and expressed in a compact form. With these DGFs obtained, the electromagnetic fields in each layer are straightforward once the current source is known. A specific model is proposed for the scattering and absorption characteristics of multilayered uniaxial anisotropic spheres, and some novel performance regarding anisotropy effects is revealed.     

Quantitative Elemental Analysis of a Single Cell by Using Inductively Coupled Plasma-Mass Spectrometry in Fast Time-Resolved Analysis Mode

The elemental composition of a single yeast, green alga, or red blood cell (RBC) was precisely determined by using inductively coupled plasma-mass spectrometry (ICP-MS) operating in fast time-resolved analysis (TRA) mode. The technique is known as single-cell (SC)-ICP-MS. Phosphorus, sulfur, magnesium, zinc, and iron were detected in the three types of cell. The elemental composition of yeast and green alga obtained by SC-ICP-MS was consistent with results obtained from conventional ICP-MS measurements following acid digestion of the cells. Slight differences were found in the measured values between SC-ICP-MS and the conventional ICP-MS results for RBC. However, the SC-ICP-MS results for S and Fe in RBC were closer to the estimated values for these elements that were calculated from the level of hemoglobin in RBCs. The data suggest that SC-ICP-MS is suitable for the analysis of various cell types, namely, fungus, plant, and animal cells.     

New trends: preperitoneal laparoscopic inguinal hernia repair

This paper focuses on the meaning and process of collaboration, particularly in the area of research and clinical practice. Much has been written about the existing gaps between research and the practice of nursing; however, action research is one mechanism that allows these elements to be drawn together. Research developed through collaborative participation has the potential to harness the energy, enthusiasm and talents of nurses at different levels and practice into a cohesive group motivated to achieve professional development and quality practice goals. Action research that is built on the philosophy of a quality within the process and significance of the group can lead to effective practice in nursing. Power can be found in partnership.     

Ethnography and Hermeneutics in Cybercultural Research Accessing IRC Virtual Communities

The Internet has penetrated China at a rapid rate. However, there exist a wide range of constraining forces, such as governmental control, inadequate infrastructure, economic affordability, cultural perceptions, and language barriers. This paper tests the impact of access to the Internet and other sources of information, perceived credibility of the Internet and conventional media, and cognitive sophistication of Chinese audiences on the choice of rival value orientations such as Communism, Materialism, and Post-materialism. The data come from a survey of 2,600 adults in Beijing and Guangzhou in November-December 2000. Multinomial logistic regression analyses show that perceived credibility of the Internet, cognitive sophistication, and access to Hong Kong-based television have a significant impact on the preference for particular value orientations. Analysis of the sub-sample of Internet users further reveals the importance of participation in online chatting. The findings bear important implications for the role of the Internet in the political development of transitional societies.     

CENTRIFUGAL FLUIDIZATION: EFFECTS OF PARTICLE DENSITY AND SIZE DISTRIBUTION

Based on the model of the centrifugal fluidized bed as a homogeneous viscous rotating fluid, the equation for conservation of momentum in the tangential direction is solved to obtain expressions for bed pressure drop and the radial variations of tangential velocity within the bed region. Comparisons with available data on bed pressure drop indicate that the fluidized bed rotates as a rigid body. Experimental data are also presented on minimum fluidization velocity and bed pressure drop with different particle densities and size distributions, verifying the validity of the available models for packed bed and fluidized bed pressure drop and minimum fluidization velocity in a centrifugal fluidized system.     

Supplementation of wheat flour with some local legumes

Egyptian bread made with broad bean flour, lentil flour, and wheat flour was scored for aroma, crust colour, crumb colour, texture, flavour and over-all acceptability by Egyptian judges. Protein quality of the bread was measured by a rat growth study. Analysis of variance for the data from the organoleptic evaluation was insignificant. The results indicate that broad bean flour could be added to wheat flour in making Egyptian Ballady bread up to 20% without affecting any of the tested characteristics. However, supplementation of wheat flour with more than 15% lentil flour might have some effect on flavour and hence on overall acceptability. The addition of 5, 10, 15 and 20% broad bean flour and lentil flour was accompained by an increase in the PER. It was clear that wheat flour supplemented with broad bean flour had a more pronounced effect on the PER at a 5 and 10% level of supplementation than that supplemented with lentil. The PER data were subjected to analysis of variance. At 1% level of significance the increase in PER for the 10, 15 and 20% broad bean breads was significant. Also the differences in the PERs between 5, 10 and 15% broad bean flour was significant. At 1% level of significance there was a significant difference in the PER values of bread made with 15 and 20% lentil flour. Incorporating broad bean flour into bread at a 20% level had a significant effect on the NPR at 1% and 5% level of significance. At 1% level of significance the only significant increase in NPR was noticed using the 20% level of lentil flour.