A Petri-Net Approach to Modular Supervision With Conflict Resolution for Semiconductor Manufacturing Systems

In a semiconductor manufacturing system, particular human operations may violate desired requirements and lead to destructive failure. For such human-in-the-loop systems, this paper proposes a supervisory framework which guarantees that manual operations meet required specifications so as to prevent human errors in operation using Petri nets. Moreover, a modular technique with an intersection mechanism is proposed in order to cope with the state-space explosion problem of large-scale systems. A rapid thermal process in semiconductor manufacturing systems is provided to show the practicability of the proposed approach. Note to Practitioners - This work was motivated by the requirement of remote monitoring and supervision of semiconductor manufacturing systems. In such human-in-the-loop and large-scale systems, certain human operations may violate desired safety requirements and result in catastrophic failure. Moreover, the overall complexity of most existing Petri net modeling and analysis approaches significantly increases with the size of the considered systems. This paper suggests a modular supervisory scheme for modeling and synthesis of supervisory agents using Petri nets. The proposed method contributes a promising tool for preventing abnormal operations from being carried out to semiconductor manufacturing systems which, if appropriately modified, may be also applied to other types of discrete event systems.     

Miniaturization of Electrostatic Fluid Accelerators

Existing thermal-management methods for electronics do not meet the technology needs and remain a major bottleneck in the evolution of computing, sensing, and information technology. The decreasing size of microelectronic components and the resulting increasing thermal output density require novel cooling solutions. Electrostatic fluid accelerators (EFAs), also known as electrohydrodynamic ionic wind pumps, have the potential of becoming a critical element of electronic thermal-management solutions. In order to take full advantage of EFA-based thermal management, it is essential to miniaturize EFA technology. This paper demonstrates the successful operation of a mesoscale microfabricated silicon EFA. Several cantilever structures fabricated in bulk silicon with radii of tip curvature ranging from 0.5 to 25 mum are used as the corona electrode. The device was fabricated using the combination of deep reactive ion etching (DRIE) and reactive ion etch (RIE) microfabrication processes. Forced convection cooling is demonstrated using infrared imaging, showing a 25degC surface temperature reduction over an actively heated substrate. The fabrication and test results of a mesoscale microfabricated EFA are presented in this paper.     

Reinforcement Hybrid Evolutionary Learning for Recurrent Wavelet-Based Neurofuzzy Systems

This paper proposes a recurrent wavelet-based neurofuzzy system (RWNFS) with the reinforcement hybrid evolutionary learning algorithm (R-HELA) for solving various control problems. The proposed R-HELA combines the compact genetic algorithm (CGA), and the modified variable-length genetic algorithm (MVGA) performs the structure/parameter learning for dynamically constructing the RWNFS. That is, both the number of rules and the adjustment of parameters in the RWNFS are designed concurrently by the R-HELA. In the R-HELA, individuals of the same length constitute the same group. There are multiple groups in a population. The evolution of a population consists of three major operations: group reproduction using the compact genetic algorithm, variable two-part crossover, and variable two-part mutation. Illustrative examples were conducted to show the performance and applicability of the proposed R-HELA method.     

Cryptanalysis and improvement of nonrepudiable threshold multi-proxy multi-signature scheme with shared verification

Recently, Tzeng et al. proposed a nonrepudiable threshold multi-proxy multi-signature scheme with shared verification. In their scheme, a subset of original signers can delegate the signing power to a group of the designated proxy signers in such a way that: (i) A valid proxy signature can only be generated by a subset of these proxy signers for a group of the designated verifiers. (ii) The validity of the generated proxy signature can only be verified by a subset of the designated verifiers. This article, however, will demonstrate a security leak inherent in Tzeng et al.’s scheme that any verifier can check the validity of the proxy signature by himself with no help of other verifiers. That is, Tzeng et al.’s scheme cannot achieve their claimed security requirement. Finally, we will propose an improvement to eliminate the pointed out security leak.     

An optimization model for the container pre-marshalling problem

In most container yards around the world, containers are stacked high to utilize yard space more efficiently. In these yards, one major factor that affects their operational efficiency is the need to re-shuffle containers when accessing a container that is buried beneath other containers. One way to achieve higher loading efficiency is to pre-marshal the containers in such a way that it fits the loading sequence. In this research, we present a mathematical model for the container pre-marshalling problem. With respect to a given yard layout and a given sequence that containers are loaded onto a ship, the model yields a plan to re-position the export containers within the yard, so that no extra re-handles will be needed during the loading operation. The optimization goal is to minimize the number of container movements during pre-marshalling. The resulting model is an integer programming model composed of a multi-commodity flow problem and a set of side constraints. Several possible variations of the model as well as a solution heuristic are also discussed. Computation results are provided.     

Node-pancyclicity and edge-pancyclicity of hypercube variants

Twisted cubes, crossed cubes, Möbius cubes, and locally twisted cubes are some of the widely studied hypercube variants. The 4-pancyclicity of twisted cubes, crossed cubes, Möbius cubes, locally twisted cubes and the 4-edge-pancyclicity of twisted cubes, crossed cubes, Möbius cubes are proven in [C.P. Chang, J.N. Wang, L.H. Hsu, Topological properties of twisted cube, Inform. Sci. 113 (1999) 147-167; C.P. Chang, T.Y. Sung, L.H. Hsu, Edge congestion and topological properties of crossed cubes, IEEE Trans. Parall. Distr. 11 (1) (2000) 64-80; J. Fan, Hamilton-connectivity and cycle embedding of the Möbius cubes, Inform. Process. Lett. 82 (2002) 113-117; X. Yang, G.M. Megson, D.J. Evans, Locally twisted cubes are 4-pancyclic, Appl. Math. Lett. 17 (2004) 919-925; J. Fan, N. Yu, X. Jia, X. Lin, Embedding of cycles in twisted cubes with edge-pancyclic, Algorithmica, submitted for publication; J. Fan, X. Lin, X. Jia, Node-pancyclic and edge-pancyclic of crossed cubes, Inform. Process. Lett. 93 (2005) 133-138; M. Xu, J.M. Xu, Edge-pancyclicity of Möbius cubes, Inform. Process. Lett. 96 (2005) 136-140], respectively. It should be noted that 4-edge-pancyclicity implies 4-node-pancyclicity which further implies 4-pancyclicity. In this paper, we outline an approach to prove the 4-edge-pancyclicity of some hypercube variants and we prove in particular that Möbius cubes and locally twisted cubes are 4-edge-pancyclic.     

消除高压噪声的继电器

大多数实验室和工业环境中都存在着多种全频带电气噪声源,它们来自于重型机器、仪表、电源和电视台.工程师要用很多设备和技术来对付这种噪声.这些技术包括采用正确的接地方式、屏蔽和双绞线、信号均化、差分输入电压放大器和滤波器.     

CMOS dual-band variable-gain amplifier for 3G-WCDMA and WLAN dual-mode RF receivers

A dual-band variable-gain amplifier (DBVGA) is presented for integrated 2.2 GHz 3G-WCDMA and 5.2 GHz WLAN transceivers. DBVGA employs a DC-and-RF current steering technique for gain control, which can minimise variations of the noise, 1 dB gain compression point, and input/output impedance when the gain is tuned. The appropriate frequency operation band of DBVGA is jointly controlled by the switched-resonator load and the input stage gate bias, resulting in high cross-band isolation and out-of-band interference rejection. All circuits except the input stages are reused for both bands to have high component reuse. A fully-integrated 0.18 mum CMOS DBVGA has been implemented to verify the proposed design     

Coupling Effect of On-Chip Inductor With Variable Metal Width

This study proposes a proper layout of on-chip inductors to diminish the coupling effect in silicon-based technology. Keeping self inductance constant, the mutual inductance is measured to characterize coupling effect in three test keys. A layout with variable metal width of inductor is found to alleviate mutual inductance. Experiment results demonstrate the mutual inductance decreases 33.5% compared with standard layout. This information will be helpful in implementation of more than one inductor into radio frequency integrated circuits (RFICs).     

High-Responsivity Photodetector in Standard SiGe BiCMOS Technology

For high-speed optoelectronic applications such as fiber-optic data communication systems, photodetectors (PDs) with high responsivity in Si-related processes are required. In this letter, a result of the effort along this line is reported. A novel device named phototransistor PD (PTPD) was realized in a commercial 0.35-mum SiGe BiCMOS technology. The device combines a surface PD (SPD) and a conventional SiGe heterojunction PT (HPT). It was shown that the SPD enhanced light absorption and the PTPD showed significant performance improvement over HPT. Responsivities of 5.2 A/W for an 850-nm light and 9.5 A/W for a 670-nm light were achieved in the PTPD, with floating base and SPD terminals.