Novel back‐channel‐etch process flow based a‐IGZO TFTs for circuit and display applications on PEN foil

In this study, we report high‐quality amorphous indium–gallium–zinc‐oxide (a‐IGZO) thin‐film transistors (TFTs) fabricated on a polyethylene naphthalate foil using a new back‐channel‐etch (BCE) process flow. The BCE flow allows a better scalability of TFTs for high‐resolution backplanes and related circuits. The maximum processing temperature was limited to less than 165 °C in order to ensure good overlay accuracy (<1 µm) on foil. The presented process flow differs from the previously reported flow as we define the Mo source and drain contacts by dry etch prior to a‐IGZO patterning. The TFTs show good electrical performance, including field‐effect mobilities in the range of 15.0 cm²/(V·s), subthreshold slopes of 0.3 V/decade, and off‐currents <1.0 pA on foil. The threshold voltage shifts of the TFTs measured were less than 1.0 V after a stressing time of 10⁴ s in both positive (+1.0 MV/cm) and negative (?1.0 MV/cm) bias directions. The applicability of this new BCE process flow is demonstrated in a 19‐stage ring oscillator, demonstrated to operate at a supply voltage of 10 V with a stage delay time of 1.35 µs, and in a TFT backplane driving a 32 × 32 active‐matrix organic light‐emitting diode display.     

Experimental evaluations of proportional–integral–derivative type fuzzy controllers with parameter adaptive methods for an active magnetic bearing system

Abstract: This paper deals with the experimental control of a rotating active magnetic bearing (AMB) system using proportional–integral–derivative type fuzzy controllers (PIDFCs) with parameter adaptive methods. Three kinds of parameter adaptive method, including fuzzy tuner, function tuner and relative rate observer, have been proposed in the literature for tuning the coefficients of PIDFCs. However, only a simulation comparison between these methods for control of a second‐order linear system with varying parameters and time delay has been done. In general, theoretical models need to be confirmed and modified through experimental results. This paper provides experimental verification by applying PIDFCs with self‐tuning algorithms for control of a highly nonlinear AMB system. It is shown that the steady‐state error of the AMB system using the function tuner method is lower and the first resonant frequency of the AMB system using the relative rate observer method is higher than the other two methods, and the proportional–integral–derivative controller is quite unstable. The experimental results also show that all of the tuning methods can support a high rotation frequency of the AMB system. In practice, there are only a few differences between the three kinds of parameter adaptive methods.     

Understanding the meaning of a shifted sky: a general framework on extending skyline query

Skyline queries are often used on data sets in multi-dimensional space for many decision-making applications. Traditionally, an object p is said to dominate another object q if, for all dimensions, it is no worse than q and is better on at least one dimension. Therefore, the skyline of a data set consists of all objects not dominated by any other object. To better cater to application requirements such as controlling the size of the skyline or handling data sets that are not well-structured, various works have been proposed to extend the definition of skyline based on variants of the dominance relationship. In view of the proliferation of variants, in this paper, a generalized framework is proposed to guide the extension of skyline query from conventional definition to different variants. Our framework explicitly and carefully examines the various properties that should be preserved in a variant of the dominance relationship so that: (1) maintaining original advantages, while extending adaptivity to application semantics, and (2) keeping computational complexity almost unaffected. We prove that traditional dominance is the only relationship satisfying all desirable properties, and present some new dominance relationships by relaxing some of the properties. These relationships are general enough for us to design new top-k skyline queries that return robust results of a controllable size. We analyze the existing skyline algorithms based on their minimum requirements on dominance properties. We also extend our analysis to data sets with missing values, and present extensive experimental results on the combinations of new dominance relationships and skyline algorithms.     

Capability and efficiency of intellectual capital: The case of fabless companies in Taiwan

It is important to increase their value by managing intellectual capital (IC), since fabless firms face an intensely competitive environment. The aim of this paper is develops a two-stage production process including IC capability and IC efficiency to characterize the IC performance of the fabless firms using a non-parametric frontier method – data envelopment analysis (DEA). The IC performance rating should be considered as a key element for achieving greater innovation and competitive advantages. The results show that IC efficiency is better than IC capability for these fabless firms; 15.8% of fabless firms perform well in both models and these firms can be treated as benchmarks for others; most firms operate at decreasing returns to scale, indicating that firms are facing a highly competitive environment; further mergers and acquisitions among firms should be considered so as to achieve economies of scale; the critical input/output measures will also help firms improve their performance and identify the key factors that impact a firm’s performance.     

Dynamic computerized testlet-based test generation system by discrete PSO with partial course ontology

For the majority of E-learning systems their important role is the electronic teachers who can assist students to learn and review courses enrolled. Unfortunately, an E-learning system does not resemble a teacher who can evaluate the current students’ learning status by the immediate class observations and adjust his/her policy accordingly. Hence, to be able to dynamically compose tests to examine students’ learning status and clear their confusions becomes an important issue. This paper argues that how to formalize test requirements dynamically and how to select suitable items effectively are two main challenges in the current researches of computerized test generation. Hence, this article proposed a novel approach that can compose suitable tests to easily and efficiently evaluate the learning statuses of students. The proposed approach obeys the Discrete Particle Swarm Optimization (DPSO) scheme and uses partial course ontology to generate tests according to the studied materials. Besides, it also harnesses the notion of testlets to construct testlet-based tests for students. In the experiments, the results show that the proposed approach can effectively formalize the tested concepts and their weights, and also generate the well-scrutinized test in accordance with the test requirements in the acceptable time.     

Algorithms for near solutions to polynomial equations

Let F(x,y)$F(x,y)$ be a polynomial over a field K$K$ and m$m$ a nonnegative integer. We call a polynomial g$g$ over K$K$ an m$m$-near solution of F(x,y)$F(x,y)$ if there exists a c∈K$c\in K$ such that F(x,g)=cx^m$F(x,g)=c{x}^m$, and the number c$c$ is called an m$m$-value of F(x,y)$F(x,y)$ corresponding to g$g$. In particular, c$c$ can be 0. Hence, by viewing F(x,y)=0$F(x,y)=0$ as a polynomial equation over K[x]$K\left[x\right]$ with variable y$y$, every solution of the equation F(x,y)=0$F(x,y)=0$ in K[x]$K\left[x\right]$ is also an m$m$-near solution. We provide an algorithm that gives all m$m$-near solutions of a given polynomial F(x,y)$F(x,y)$ over K$K$, and this algorithm is polynomial time reducible to solving one variable equations over K$K$. We introduce approximate solutions to analyze the algorithm. We also give some interesting properties of approximate solutions.     

Falcon: neural fuzzy control and decision systems using FKP and PFKP clustering algorithms.

Neural fuzzy networks proposed in the literature can be broadly classified into two groups. The first group is essentially fuzzy systems with self-tuning capabilities and requires an initial rule base to be specified prior to training. The second group of neural fuzzy networks, on the other hand, is able to automatically formulate the fuzzy rules from the numerical training data. Examples are the Falcon-ART, and the POPFNN family of networks. A cluster analysis is first performed on the training data and the fuzzy rules are subsequently derived through the proper connections of these computed clusters. This correspondence proposes two new networks: Falcon-FKP and Falcon-PFKP. They are extensions of the Falcon-ART network, and aimed to overcome the shortcomings faced by the Falcon-ART network itself, i.e., poor classification ability when the classes of input data are very similar to each other, termination of training cycle depends heavily on a preset error parameter, the fuzzy rule base of the Falcon-ART network may not be consistent Nauck, there is no control over the number of fuzzy rules generated, and learning efficiency may deteriorate by using complementarily coded training data. These deficiencies are essentially inherent to the fuzzy ART, clustering technique employed by the Falcon-ART network. Hence, two clustering techniques--Fuzzy Kohonen Partitioning (FKP) and its pseudo variant PFKP, are synthesized with the basic Falcon structure to compute the fuzzy sets and to automatically derive the fuzzy rules from the training data. The resultant neural fuzzy networks are Falcon-FKP and Falcon-PFKP, respectively. These two proposed networks have a lean and efficient training algorithm and consistent fuzzy rule bases. Extensive simulations are conducted using the two networks and their performances are encouraging when benchmarked against other neural and neural fuzzy systems.     

Flexible ultrathin metamaterial absorber for wide frequency band,based on conductive fibers

Flexible and ultrathin wide-band metamaterial absorbers are suggested and demonstrated in the microwave-frequency range. By using resonators of different sizes and conductive fibers on metallic-pattern layer, the total thickness of metamaterial absorber is reduced to be only 1/349 with respect to the operating wavelength at 0.97 GHz. We present the absorption mechanism in terms of the impedance matching with the free space, the distributions of surface current and the three-dimensional distributions for power loss. In simulation, the absorption was over 97% at 0.97–6.12 GHz, and the corresponding experimental absorption band over 97% was 0.87–6.11 GHz. Furthermore, the dielectric substrate of metamaterial absorbers was replaced with flexible substrate in order to have the flexibility and the broadband absorption properties. The absorption band is expanded and the high-absorption performance maintains at the same time. The total thickness of metamaterial absorber comes to be only 1/5194 of the operating wavelength at 0.75 GHz. Our work is expected to contribute to the flexible microwave/electronic devices in the near future.     

Self‐Assembled Au/CdSe Nanocrystal Clusters for Plasmon‐Mediated Photocatalytic Hydrogen Evolution

Plasmon‐mediated photocatalytic systems generally suffer from poor efficiency due to weak absorption overlap and thus limited energy transfer between the plasmonic metal and the semiconductor. Herein, a near‐ideal plasmon‐mediated photocatalyst system is developed. Au/CdSe nanocrystal clusters (NCs) are successfully fabricated through a facile emulsion‐based self‐assembly approach, containing Au nanoparticles (NPs) of size 2.8, 4.6, 7.2, or 9.0 nm and CdSe quantum dots (QDs) of size ≈3.3 nm. Under visible‐light irradiation, the Au/CdSe NCs with 7.2 nm Au NPs afford very stable operation and a remarkable H₂‐evolution rate of (10× higher than bare CdSe NCs). Plasmon resonance energy transfer from the Au NPs to the CdSe QDs, which enhances charge‐carrier generation in the semiconductor and suppresses bulk recombination, is responsible for the outstanding photocatalytic performance. The approach used here to fabricate the Au/CdSe NCs is suitable for the construction of other plasmon‐mediated photocatalysts.     

Interface microstructure evolution of lead-free solder on Ni-based under bump metallizations during reflow and high temperature storage

The interface microstructure interaction between SnCuAg Pb-free solder and three different Ni-based alloys under bump metallization (UBM) systems are studied using transmission electron microscopy (TEM). Ni reacts with Sn-rich Pb-free solder swiftly and is consumed readily by Pb-free solder. Thermally stable intermetallic compounds at the solder/UBM interface such as Cu/sub 6/Sn/sub 5/ or Ni/sub 3/P are necessary to protect Ni from being penetrated by Pb-free solders. Interface microstructure study reveals the potential process and reliability issues when applying Pb-free solders on existing UBM systems. Cu/Ni(V)/Al, can be used for Pb-free solder with marginal thermal budget. Au/Ni(V)/Ti/Al, is not suitable for Pb-free solder. And Au/eNi(P)/Al, is the most suitable for Pb-free solder and shows best thermal stability.