Roaming across wireless local area networks using SIM-based authentication protocol

Wireless local area networks provide high speed data transferring rate to a mobile device. And it is crucial to integrate together two critical issues, the authentication and roaming in heterogeneous networks. For this, Tsai and Chang proposed a SIM-based authentication mechanism for wireless local area networks in 2006. Tsai and Chang's scheme provides an integration method of mobile cellular networks and wireless local area networks. Unfortunately, we found that there are some weaknesses existing in their scheme. In this paper, we propose an improved version for a user roaming in heterogeneous networks. Besides, we also proposed a mobile IP model to provide a better efficiency for a mobile user in WLAN environment.     

Tool support for learning Büchi automata and linear temporal logic

We introduce a graphical interactive tool, named GOAL, that can assist the user in understanding Büchi automata, linear temporal logic, and their relation. Büchi automata and linear temporal logic are closely related and have long served as fundamental building blocks of linear-time model checking. Understanding their relation is instrumental in discovering algorithmic solutions to model checking problems or simply in using those solutions, e.g., specifying a temporal property directly by an automaton rather than a temporal formula so that the property can be verified by an algorithm that operates on automata. One main function of the GOAL tool is translation of a temporal formula into an equivalent Büchi automaton that can be further manipulated visually. The user may edit the resulting automaton, attempting to optimize it, or simply run the automaton on some inputs to get a basic understanding of how it operates. GOAL includes a large number of translation algorithms, most of which support past temporal operators. With the option of viewing the intermediate steps of a translation, the user can quickly grasp how a translation algorithm works. The tool also provides various standard operations and tests on Büchi automata, in particular the equivalence test which is essential for checking if a hand-drawn automaton is correct in the sense that it is equivalent to some intended temporal formula or reference automaton. Several use cases are elaborated to show how these GOAL functions may be combined to facilitate the learning and teaching of Büchi automata and linear temporal logic. This work was partially supported by the National Science Council, Taiwan (R.O.C.) under grants NSC94-2213-E-002-089, NSC95-2221-E-002-127, NSC95-3114-P-001-001-Y02 (iCAST 2006), NSC96-3114-P-001-002-Y (iCAST 2007), and NSC97-2221-E-002-074-MY3.     

Constructive approximation to real function by wavelet neural networks

We present a type of single-hidden layer feed-forward wavelet neural networks. First, we give a new and quantitative proof of the fact that a single-hidden layer wavelet neural network with n + 1 hidden neurons can interpolate n + 1 distinct samples with zero error. Then, without training, we constructed a wavelet neural network X _a (x, A), which can approximately interpolate, with arbitrary precision, any set of distinct data in one or several dimensions. The given wavelet neural network can uniformly approximate any continuous function of one variable.     

Femtosecond laser-induced silicon surface morphology in water confinement

This article investigates the use of femtosecond laser induced surface morphology on silicon wafer surface in water confinement. Unlike irradiation of silicon surfaces in the air, there are no laser induced periodic structures, but irregular roughness is formed when the silicon wafer is ablated under water. The unique discovery of a smoothly processed silicon surface in water confinement under certain laser parameter combinations may help improve laser direct micromachining surface quality in industrial applications.     

Design and fabrication of novel micro electromagnetic actuator

This study designs, fabricates, and characterizes a novel micro electromagnetic actuator comprising a PDMS diaphragm, a polyimide-coated copper micro coil, and a permanent magnet. When an electrical current is passed through the micro coil, a magnetic force is induced between the coil and the magnet which causes the diaphragm to deflect, thereby creating an actuation effect. The experimental results demonstrate that the diaphragm deflection can be accurately controlled by regulating the current passed through the micro coil. It is shown that the maximum diaphragm deflection within elastic limits is 150 μm; obtained by passing a current of 0.6 A through a micro coil with a line width of 100 μm. The micro actuator proposed in this study is easily fabricated and is readily integrated with existing bio-medical chips due to its planar structure.     

Experimental verification of an out-of-plane repulsive-force electrostatic actuator using a macroscopic mechanism

A macroscopic mechanism is developed to verify a repulsive-force electrostatic actuator, which consists of an array of fixed finger electrodes and an array of moving finger electrodes. The actuator is able to generate an asymmetric electric field surrounding the top and bottom surfaces of each moving finger electrode to push the moving finger up and away from the fixed fingers. The macroscopic mechanism consists of a macro repulsive force actuator, a high voltage power supply, a z-stage, a high precision balance and a LCR meter. The force and capacitance characteristic curves of the actuator are obtained using the macro mechanism. The 3-stage force (repulsive, zero and attractive forces) of the actuator is verified, as well as the effects of the moving finger width on the actuator’s performance. Experimental tests show that the macro repulsive-force actuator can generate a repulsive force of 3,000 μN with a maximum gap of 9.5 mm for generating a repulsive force.     

Understanding factors affecting trust in and satisfaction with mobile banking in Korea: A modified DeLone and McLean’s model perspective

As mobile technology has developed, mobile banking has become accepted as part of daily life. Although many studies have been conducted to assess users’ satisfaction with mobile applications, none has focused on the ways in which the three quality factors associated with mobile banking – system quality, information quality and interface design quality – affect consumers’ trust and satisfaction. Our proposed research model, based on DeLone and McLean’s model, assesses how these three external quality factors can impact satisfaction and trust. We collected 276 valid questionnaires from mobile banking customers, then analyzed them using structural equation modeling. Our results show that system quality and information quality significantly influence customers’ trust and satisfaction, and that interface design quality does not. We present herein implications and suggestions for further research.     

Minimizing a nonlinear function under a fuzzy max-t-norm relational equation constraint

This work studies a nonlinear optimization problem subject to fuzzy relational equations with max-t-norm composition. Since the feasible domain of fuzzy relational equations with more than one minimal solution is non-convex, traditional nonlinear programming methods usually cannot solve them efficiently. This work proposes a genetic algorithm to solve this problem. This algorithm first locates the feasible domain through the maximum solution and the minimal solutions of the fuzzy relational equations, to significantly reduce the search space. The algorithm then executes all genetic operations inside this feasible domain, and thus avoids the need to check the feasibility of each solution generated. Moreover, it uses a local search operation to fine-tune each mutated solution. Experimental results indicate that the proposed algorithm can accelerate the searching speed and find the optimal solution.     

Imbalanced text classification: A term weighting approach

The natural distribution of textual data used in text classification is often imbalanced. Categories with fewer examples are under-represented and their classifiers often perform far below satisfactory. We tackle this problem using a simple probability based term weighting scheme to better distinguish documents in minor categories. This new scheme directly utilizes two critical information ratios, i.e. relevance indicators. Such relevance indicators are nicely supported by probability estimates which embody the category membership. Our experimental study using both Support Vector Machines and Naïve Bayes classifiers and extensive comparison with other classic weighting schemes over two benchmarking data sets, including Reuters-21578, shows significant improvement for minor categories, while the performance for major categories are not jeopardized. Our approach has suggested a simple and effective solution to boost the performance of text classification over skewed data sets.     

Fuzzy multiple goal programming applied to TFT-LCD supplier selection by downstream manufacturers

In today’s highly competitive environment, a good supply chain relationship is essential for a company to survive and to acquire reasonable profit. While a few large companies may be able to vertically integrate from the design stage to the final distribution of the entire supply chain, most companies can only focus on their specialized functions and to cooperate with upstream or downstream companies. Supplier selection, as a result, is very important for maintaining strategic alliances. The objective of this paper is to develop a fuzzy multiple goal programming (FMGP) model to help downstream companies to select thin film transistor liquid crystal display (TFT-LCD) suppliers for cooperation. Fuzzy analytic hierarchy process (FAHP) is applied first to analyze the importance of multiple factors by incorporating experts’ opinion, and these factors include cost, yield and number of suppliers. Multi-choice goal programming is used next to consider the limits of various resources and to formulate the constraints. From the experimental design and examination, we can testify that the proposed model not only can consider multi-choice goals, decision-making behavior and limit of resources, it can also allocate the purchase among the selected supplier(s).