A novel manufacturing defect detection method using association rule mining techniques

In recent years, manufacturing processes have become more and more complex, and meeting high-yield target expectations and quickly identifying root-cause machinesets, the most likely sources of defective products, also become essential issues. In this paper, we first define the root-cause machineset identification problem of analyzing correlations between combinations of machines and the defective products. We then propose the Root-cause Machine Identifier (RMI) method using the technique of association rule mining to solve the problem efficiently and effectively. The experimental results of real datasets show that the actual root-cause machinesets are almost ranked in the top 10 by the proposed RMI method.     

Low-frequency noise in TaSiN/HfO/sub 2/ nMOSFETs and the effect of stress-relieved preoxide interfacial layer

Low-frequency noise characteristics are reported for TaSiN-gated n-channel MOSFETs with atomic-layer deposited HfO/sub 2/ on thermal SiO/sub 2/ with stress-relieved preoxide (SRPO) pretreatment. For comparison, control devices were also included with chemical SiO/sub 2/ resulting from standard Radio Corporation of America clean process. The normalized noise spectral density values for these devices are found to be lower when compared to reference poly Si gate stack with similar HfO/sub 2/ dielectric. Consequently, a lower oxide trap density of /spl sim/4/spl times/10/sup 17/ cm/sup -3/eV/sup -1/ is extracted compared to over 3/spl times/10/sup 18/ cm/sup -3/eV/sup -1/ values reported for poly Si devices indicating an improvement in the high-/spl kappa/ and interfacial layer quality. In fact, this represents the lowest trap density values reported to date on HfO/sub 2/ MOSFETs. The peak electron mobility measured on the SRPO devices is over 330 cm/sup 2//V/spl middot/s, much higher than those for equivalent poly Si or metal gate stacks. In addition, the devices with SRPO SiO/sub 2/ are found to exhibit at least /spl sim/10% higher effective mobility than RCA devices, notwithstanding the differences in the high-/spl kappa/ and interfacial layer thicknesses. The lower Coulomb scattering coefficient obtained from the noise data for the SRPO devices imply that channel carriers are better screened due to the presence of SRPO SiO/sub 2/, which, in part, contributes to the mobility improvement.     

Exploiting locality for irregular scientific codes

Irregular scientific codes experience poor cache performance due to their irregular memory access patterns. In this paper, we present two new locality improving techniques for irregular scientific codes. Our techniques exploit geometric structures hidden in data access patterns and computation structures. Our new data reordering (GPART) finds the graph structure within data accesses and applies hierarchical clustering. Quality partitions are constructed quickly by clustering multiple neighbor nodes with priority on nodes with high degree and repeating a few passes. Overhead is kept low by clustering multiple nodes in each pass and considering only edges between partitions. Our new computation reordering (Z-SORT) treats the values of index arrays as coordinates and reorders corresponding computations in Z-curve order. Applied to dense inputs, Z-SORT achieves performance close to data reordering combined with other computation reordering but without the overhead involved in data reordering. Experiments on irregular scientific codes for a variety of meshes show locality optimization techniques are effective for both sequential and parallelized codes, improving performance by 60-87 percent. GPART achieved within 1-2 percent of the performance of more sophisticated partitioning algorithms, but with one third of the overhead. Z-SORT also yields the performance improvement of 64 percent for dense inputs, which is comparable with data reordering combined with computation reordering.     

Proactive DAD: A Fast Address-Acquisition Strategy for Mobile IPv6 Networks

The increasing number of Wi-Fi-compatible mobile devices highlights various wireless access challenges, including the need for smooth hand offs between Internet attachment points in mobile IPv6 networks. To confirm address uniqueness in a new domain, mobile nodes must run duplicate address detection (DAD), which is a time-consuming process. The Proactive DAD approach uses topology information and layer-2 signals to predict the new network domains prior to or in parallel with layer-3 hand offs. Experimental results show that P-DAD can significantly reduce both hand-off latency and packet loss     

Characterization of closed-loop measurement accuracy in precision CNC milling

This study investigates the closed-loop measurement error in computer numerical controlled (CNC) milling as they relate to the different inspection techniques. The on-line inspection of machining accuracy using a spindle probe has an inherent shortcoming because the same machine-produced parts are used for inspection. In order to use the spindle probe measurement as a means of correcting deviations in machining, the magnitude of measurement errors needs to be quantified. The empirical verification was made by conducting three sets of cutting experiments, followed by a design of experiment with three levels and three factors on a state-of-the-art CNC machining center. Three different material types and parameter settings were selected to simulate a diverse cutting condition. During the cutting, the cutting force and spindle vibration sensor signals were collected and a tool wear was recorded using a computer vision system. The bore tolerance was gauged by a spindle probe as well as a coordinate-measuring machine. The difference between the two measurements was defined as a closed-loop measurement error and the subsequent analysis was performed to determine the significant factors affecting the errors. The analysis results showed the potential of improving production efficiency and improved part quality.     

A spectral-discrimination method for tear-film lipid-layer thickness estimation from fringe pattern images

Examination of the tear-film lipid layer is often helpful in the prognosis of prospective contact lens patients and contact lens related problems, and in the analysis of symptomatic noncontact lens-wearing patients. In particular, the thickness of the lipid layer is considered to be an informative cue in studying the tear-film stability and uncovering of certain disorders. We propose a method for the accurate estimation of the lipid-layer thickness, exploiting the intensity and color information in Fizeau fringe images. The technique is based on a quantitative measure for discriminating among the spectra associated with different thicknesses. We propose an optical system for imaging the interference patterns, develop a mathematical model based on the physics of the fringe formation and sensing, and describe the calibration of the optical system using this model. The thickness extraction is readily carried out utilizing a lookup table. The proposed method would enable objective evaluation of the lipid layer characteristics, and provide a means for examining the dynamic changes in its thickness and spatial distribution during inter-blink periods.     

Evaluation of transglutaminase on the quality of low-salt chicken meat-balls

The purpose of this study was to examine the effect of different concentrations of crude pig plasma transglutaminase (TGase) at 0, 0.05, 0.1, 0.2, 0.4 and 1.0% on the quality of low-salt chicken meat-balls. Yield, color, gel strength, microstructure and sensory evaluation were measured. The results showed that both the yield and gel strength of the meat-balls increased as TGase supplement increased (P<0.05) without any obvious effect on color. Scanning electron microscopy (SEM) indicated firmer and more regular gel structures with increasing TGase addition. Texture, juiciness and overall acceptability as judged by sensory evaluation were not statistically affected until the level of TGase reached 1.0% (P<0.05).     

An ultra-precision XYtheta(Z) piezo-micropositioner. I. Design and analysis

A novel three degree-of-freedom micropositioner was developed for deep ultraviolet lithography applications. The design of the micropositioner utilizes the monolithic flexural mechanism with built-in multilayer piezoelectric actuators and sensors to achieve translations in the X- and Y-axes and rotation in the theta(Z)-axis. The compact design aims at high resolution, high stiffness, and extremely low crosstalk interference. Parametric analyses of harmonic and forced vibrations are conducted to solve the derived dynamic models for the near optimum geometry of the micropositioner. Furthermore, the error budget analysis is conducted to minimize the effects of the geometric tolerance, material variation, and hysteresis errors.     

A new method to extract gate coupling ratio and oxide trapped charge in flash memory cell

A new method to obtain the gate coupling ratio (α_g) and oxide trapped charge (Q_ox) as a result of cycling in flash memory cells is described here. Three cells with an equivalent physical structure but different erase characteristics are measured. The threshold changes versus erase times are fitted to the charge removal rate calculated based on Fowler-Nordheim (FN) tunneling and the capacitive relations among all nodes. The extracted α_g is independent of technologies and this method is particular useful when the profile of the floating gate is not traditionally rectangular owing to advanced processes such as trapezoidal poly etch or a poly-spacer addition on the floating gate sidewall. The Q_ox can also be determined once α_g is extracted.     

Effect of antioxidant in endothelial cells exposed to oxidized low-density lipoproteins

Antioxidants such as probucol and alpha-tocopherol have been shown to attenuate the oxidation of low-density lipoproteins (LDL) and atherosclerotic lesions in animal models of atherosclerosis. The purpose of this study is to determine the protection effect of antioxidants on endothelial cells when exposed to oxidized and native LDL. In a cell-free system, we found that probucol, alpha-tocopherol, and ascorbic acid inhibited copper-induced LDL oxidation by a dose-dependent fashion (from 1 microM to 10 mM). In porcine aortic endothelial cells, antioxidants alone did not change basal endothelin-1 (ET-1) secretion. When porcine aortic endothelial cells were exposed to LDL and oxidized-LDL, both of them stimulated ET-1 secretion dose-dependently, whereas oxidized-LDL elicited higher ET-1 secretion. However, probucol, alpha-tocopherol, and ascorbic acid did not prevent LDL or oxidized-LDL induced ET-1 secretion. Furthermore, nimodipine inhibited both of native and oxidized LDL induced ET-1 secretion. Since Ca2+ channel blocker reduced the elevation of induced ET-1 secretion, the [Ca2+]i is possibly involved for the regulation of ET-1 secretion. Our results suggest that antioxidants can only prevent the oxidation of LDL rather than oxidized and native LDL-induced ET-1 secretion in vascular endothelial cells. The increase in the [Ca2+]i of endothelial cells through the opening of voltage-dependent Ca2+ channels may be involved in the LDL-induced ET-1 release.