A new spatial IP assignment method for IP-based wireless sensor networks

Wireless sensor networks (WSNs), one of the commercial wireless mesh networks (WMNs), are envisioned to provide an effective solution for sensor-based AmI (Ambient Intelligence) systems and applications. To enable the communications between AmI sensor networks and the most popular TCP/IP networks seamlessly, the best solution model is to run TCP/IP directly on WSNs (Mulligan et al. 2009; Hui and Culler 2008; Han and Mam 2007; Kim et al. 2007; Xiaohua et al. 2004; Dunkels et al. 2004; Dunkels et al. 2004; Dunkels 2001; Dunkels et al. 2004). In this case, an IP assignment method is required to assign each sensor node a unique IP address. SIPA (Dunkels et al. 2004) is the best known IP assignment method that uses spatial relations and locations of sensor nodes to assign their IP addresses. It has been applied in Contiki (Dunkels et al. 2004), a famous WSN operating system, to support the 6LowPAN protocol. In Chang et al. (2009), we proposed the SLIPA (Scan-Line IP Assignment) algorithm to improve the assignment success rate (ASR) obtained by SIPA. SLIPA can achieve a good ASR when sensor nodes are uniformly distributed. However, if sensor nodes are deployed by other distributions, the improvements would be limited. This paper proposes a new spatial IP assignment method, called SLIPA-Q (SLIPA with equal-quantity partition), to improve SLIPA. Experiments show that, by testing the proposed method 1,000 times with 1,000 randomly deployed sensor nodes, the average ASR obtained by SLIPA-Q is over two times of that obtained by SLIPA. Under the same 88% ASR, the average numbers of sensor nodes those can be successfully assigned by SLIPA-Q, SLIPA, and SIPA are 950, 850, and 135, respectively. Comparing to previous spatial IP assignment methods, SLIPA-Q can achieve dramatic improvements in ASR for assigning IP addresses to a large set of sensor nodes.     

Consideration factors and adoption of type,tabulation and framework for creating e-portfolios

The purpose of this research is to analyze the content of e-portfolios created by students in order to understand their tabulation and ways of displaying content. The analytic result shows that the number of outcome portfolios created by students is more than that of process portfolios. The five types of e-portfolio tabulation, in order of those most commonly created by students, are combination-based, content item-based, work-based, course unit-based, and time-based. The combination-based type incorporates the advantages of other tabulation types, while the content item-based and work-based types are better for clearly classifying data and step-by-step organization of it. Future research may further explore factors related to students’ decision of tabulation type, the difficulties they face in the process, and their mentality as they adopt a portfolio type.     

Electropolishing of 304 stainless steel: Interactive effects of glycerol content, bath temperature, and current density on surface roughness and morphology

In this study, surface roughness of 304 stainless steel (304SS) varying from ca. 7 to 45 nm can be controlled by changing electropolishing variables in glycerol-containing baths. On the basis of the adsorbate-acceptor mechanism and the model for preferential adsorption of shielding molecules, incorporating the molecular interaction concept is helpful to explain the interactive effects of glycerol content, bath temperature, and current density on the surface roughness (Ra) and morphologies of 304SS. In order to easily understand how to control the surface roughness of 304SS in the glycerol-containing electrolyte, a simplified scheme integrating the above two mechanisms was proposed. From the atomic force microscopy (AFM) analyses, a rough surface is easily obtained by electropolishing at high bath temperatures, which endows the 304SS substrate with pores.     

The indirect synthesized method induced relaxor state to ferroelectric characteristics for Pb0.95La0.05(Fe2/3W1/3)0.65Ti0.35O3 ceramics

Pb_0.95La_0.05(Fe_2/3W_1/3)_0.65Ti_0.35O₃ ceramics are synthesized by using the conventional direct oxide synthesized (DS) method and the indirect synthesized (IS) method. The low-field dielectric response is investigated by using the empirical law, two ordering models and the space charge polarization. The temperature-dependent dielectric peak of the samples prepared using the IS synthesized method is obviously increased; the temperature-dielectric constant is changed to sharp and the diffused phase characteristic is decreased. It is concluded that the IS synthesized method can change the dielectric natures from a relaxor like behavior to a sharp ferroelectric state. The space charge polarization is also changed by using the IS synthesized method. According to these results, it is suggested that the 1:1 ordered domain is enhanced based on the random-site type by using the IS synthesized method for Pb_0.95La_0.05(Fe_2/3W_1/3)_0.65Ti_0.35O₃ ceramics. However, if the sintering temperature is not high enough for some calcined powders, the random-site type can be changed to the space charge type.     

The fuzzy crystallization algorithm: a new approach to complexsystems modeling

A new identification method for fuzzy modeling is introduced. Since the method has some analogy with the process of material crystallization in nature, the name of fuzzy crystallization algorithm (FCA) is given to this novel approach. This method accomplishes structure identification and parameter identification at the same time, and possesses the properties of simplicity, flexibility, and high calculation speed. Compared with other modeling strategies, it is easier to construct a model with a specific accuracy. Numerical examples are provided to demonstrate the performance of this approach.     

Precise looper simulation for hot strip mills using an auto-tuning approach

A looper is an uplifted device, which is always installed between adjacent stands in a hot strip finishing mill. A virtual looper system incorporating powerful computation capability of digital computers becomes an efficient and cost-effective tool for controller design and system analysis of this complicated and gigantic system. Accurate simulation of the looper system can not only restore the actual looper’s dynamic behavior, but can also analyze the factors that affect the looper response and provide useful information for further improvement of the control system. In this paper, a looper simulation system based on a conventional hot strip mill is established. Sensitivity analysis indicates that the reduction ratio is the most important parameter for the looper dynamics. Therefore, an auto-tuning technique for a variable reduction ratio is developed. Simulation results, compared with actual loopers behavior, demonstrate significant improvement in terms of accuracy.     

Outdoor ubiquitous learning or indoor CAL? Achievement and different cognitive loads of college students

The purpose of the present study was to examine the differences in English listening achievement and three types (intrinsic, extraneous, and germane) of cognitive load between outdoor ubiquitous learning (u-learning) and indoor computer-assisted learning (CAL). Participants included 160 university students taking a freshman English course, with 53 males and 107 females. They were randomly assigned to either an experimental group (outdoor u-learning) with 80 participants or a control group (indoor CAL) with 80 participants. The instructional experiment lasted three weeks. The results showed that (a) the experimental group had significantly better English listening achievement than the control group; (b) the experimental group had significantly lower extraneous but higher germane cognitive load than the control group, and both groups did not have a significantly different intrinsic cognitive load; (c) there was a significantly negative relationship between English listening achievement and extraneous cognitive load, a significantly positive relationship between English listening achievement and germane cognitive load, but no significant relationship between English listening achievement and intrinsic cognitive load; and (d) among three types of cognitive loads, only extraneous and germane cognitive loads had a significant correlation. The study may provide some implications for English teaching and u-learning.     

Effect of under-layer treatment of Ta/TaN barrier film on corrosion between Cu seed and Ta in chemical-mechanical-polishing slurry

Tantalum/tantalum nitride (Ta/TaNx) composite film is widely used as a copper (Cu) diffusion barrier layer. In order to reduce via-resistance, an additional argon (Ar) re-sputtering process is used to thin the barrier thickness at the feature bottom. In this study, the effect of Ar re-sputtering of the under-layer of TaNx barrier films on the corrosion between Cu seeds and upper Ta films in chemical-mechanical-polishing (CMP) slurries was investigated. The results show that Ar re-sputtering of the under-layer of the TaNx barrier has a strong influence on the corrosion of Cu seeds and Ta films. The equivalent circuit, simulated using data from electrochemical analysis, reveals changes in resistance and capacitance elements of the Cu-Ta electrochemical system, proving that the phase transformation of upper Ta films under different TaNx conditions leads to different degrees corrosion of Cu seeds and the Ta films.     

A comparative analysis of the consistency and difference among teacher-assessment, student self-assessment and peer-assessment in a Web-based portfolio assessment environment for high school students

This study explored the consistency and difference of teacher-, student self- and peer-assessment in the context of Web-based portfolio assessment. Participants were 72 senior high school students enrolled in a computer application course. Through the assessment system, the students performed portfolio creation, inspection, self- and peer-assessment; three teachers reviewed portfolios and evaluated learning performances. There were significant differences in the results of the three assessment methods, among which teacher-raters adopted the most rigorous scoring standards, while peer-raters tended to use the most lax standards. The results of self- and teacher-assessment were discovered to be consistent; however, consistency was not discovered between self- and peer-assessment as well as peer- and teacher-assessment. In analyzing their consistency with the end-of-course examination, teacher- and self-assessment demonstrated high consistency, whereas peer-assessment showed a low level of consistency.