Analysis of the correlation between acoustic noise and vibration generated by a multi-layer ceramic capacitor

Acoustic noise generated by a multi-layer ceramic capacitor (MLCC) makes users uncomfortable, so the problem must be analyzed to reduce the noise. There is a correlation between the acoustic noise and the vibration of MLCCs and the circuit board. Therefore, the acoustic noise problem must be investigated from a vibration perspective. In this study, the acoustic noise-generating mechanism was investigated, and the relationship between the characteristics of the noise and the dynamic characteristics of the circuit board with MLCC was analyzed. And a correlation criterion was proposed to predict the acoustic noise using the vibration response of the circuit board.     

Binary blends of nylons with ethylene vinyl alcohol copolymers: Morphological,thermal, rheological,and mechanical behavior

Binary blends of ethylene vinyl alcohol copolymers, containing 62 (EVOH-62) and 71 (EVOH-71) mole percent vinyl alcohols, with nylons (nylon-6, nylon-6/12, and nylon-12) have been prepared from melt mixing in a twin screw compounding machine. Morphological, thermal, rheological, and mechanical properties were determined. EVOH-62/nylon-6 and EVOH-71/nylon-6 blends showed homogeneous phase morphologies in the nylon-6-rich region, and fine phase separations (c.a. 2 × 10^?7 m) in the EVOH-rich region. Melting point depression, positive deviations in viscosity and flexural modulus, and negative deviation in impact strength from the simple additive rule were generally observed. And the results were possibly interpreted in terms of compatibility and increased nylon/EVOH interactions over the nylon/nylon interactions. On the contrary, clean phase separations in large domains were observed from EVOH-71/nylon-6/12 and EVOH-71 /nylon-12 blends. Fibrillation was also obtained from EVOH rich blends. Probably due to the incompatible nature of these blends, yield at low rate of shear and a mechanical property drop were also observed.     

Nitrogen removal using recycled polystyrene bottles as biofilm media

The performance of an attached growth wastewater treatment process was investigated in an effort to improve nitrogen removal efficiency. Recycled Yakult (lactic acid fermentation drink) bottles made of polystyrene were used as a biofilm media. The use of Yakult bottles as a biofilm media has been attempted by numerous researchers in Japan for the removal of solids and organics. However, these studies focused only on the removal of solids and organics. This study extended their application to the removal of nitrogen for domestic sewage treatment. Yakult media was placed in a reactor with 70% apparent reactor volume in a conventional A/O process. The bottom of the Yakult media was removed, and randomly filled Yakult media were effectively able to reduce the flow in tanks, resulting in an increase in the contact time between pollutants and microorganisms. With higher HRT, the nitrogen removal efficiency was increased by up to 83% with 12 hr of HRT. Nitrification appeared to be the limiting factor of nitrogen removal at an HRT that is less than 12 hr, indicating that the Yakult process requires more retention time to achieve nitrification compared to other biofilm processes. The removal efficiencies of organics and solids were high regardless of the change of operational parameters. This article is based on a presentation in “The 7th Korea-China Workshop On Advanced Materials” organized by the Korea-China Advanced Materials Cooperation Center and the China-Korea Advanced Materials Cooperation Center, held at Ramada Plaza Jeju Hotel, Jeju Island, Korea on August 24–27, 2003.     

DCT statistics-based digital dropout detection in degraded archived media

With the rapid development of visual digital media, the demand for better quality of service has increased the pressure on broadcasters to automate their error detection and restoration activities for preserving their archives. Digital dropout is one of the defects that affect archived visual materials and tends to occur in block by block basis (size of 8 × 8). It is well established that human visual system (HVS) is highly adapted to the statistics of its visual natural environment. Consequently, in this paper, we have formulated digital dropout detection as a classification problem which predicts block label based on statistical features. These statistical features are indicative of perceptual quality relevant to human visual perception, and allow pristine images to be distinguished from distorted ones. Here, the idea is to extract discriminant block statistical features based on discrete cosine transform (DCT) coefficients and determine an optimal neighborhood sampling strategy to enhance the discrimination ability of block representation. Since this spatial frame based approach is free from any motion computation dependency, it works perfectly in the presence of fast moving objects. Experiments are performed on video archives to evaluate the efficacy of the proposed technique.     

Formation stabilization and resizing based on the control of inter‐agent distances

We propose a control strategy that could steer the group of mobile agents in the plane to achieve a specified formation. The control law could be implemented in a fully decentralized manner so that each agent moves on their own local reference frame. Under the acyclic minimally persistent graph topology, each agent measures the relative displacements of neighboring agents and then adjusts the distances between them to achieve the desired formation. As well as achieving a fixed formation, we could resize the formation only by changing the leader edge, which connects the leader with the first‐follower in acyclic minimally persistent graph, without changing the structures of the control law. Copyright © 2014 John Wiley & Sons, Ltd.     

Cognitive evaluation for conceptual design: cognitive role of a 3D sculpture tool in the design thinking process

ABSTRACT

This study focuses on the decisive role played by the digital design environment in the cognitive design process and design thinking. To analyse the cognitive role of digital design tools, we carried out a protocol analysis of conventional design sketching and a 3D sculpture tool. Cognitive evaluation was a differentiating factor when considering the contextual role of the 3D sculpture tool in subsequent evaluations, non-sequential evaluations for conversion, and passive approaches within the design process. Cognitive evaluation played the following roles: validation, extension, navigation, exploration, and confirmation. The navigation, exploration, and extension roles played by non-sequential evaluation were mainly related to inductive design thinking. Finally, the types of cognitive evaluation and their roles when using the 3D sculpture tool were different, according to the design thinking type. This study explored the multidimensional roles of cognitive evaluation using a 3D sculpture tool and its relationship with design thinking types.     

Collapse-free thermal bonding technique for large area microchambers in plastic lab-on-a-chip applications

Bonding is an essential step to form microchannels or microchambers in lab-on-a-chip applications. In this paper, we present a novel plastic thermal bonding technique to seal and form large area microchambers (planar characteristic width and length on the order of 1 mm and characteristic thickness on the order of 10–100 μm) without collapse by introducing a holed pressure equalizing plate (HPEP) that includes holes of the same size and shape as the microchambers. To demonstrate the proposed technique, two types of large area microchambers [(1) 20 × 10 mm and 40 μm thick and (2) 12 × 2.5 mm and 120 μm thick] with microchannels were designed and replicated on plastic substrates by means of hot embossing and injection molding processes with prepared two nickel mold inserts. The replicated large area microchambers as well as the microchannels in the plastic lab-on-a-chip were successfully sealed (i.e., no leakage) and formed without any collapse by the proposed thermal bonding technique with the help of the HPEP.     

12.1‐in. WXGA AMOLED display driven by InGaZnO thin‐film transistors

Abstract— A full‐color 12.1‐in.WXGA active‐matrix organic‐light‐emitting‐diode (AMOLED) display was, for the first time, demonstrated using indium‐gallium‐zinc oxide (IGZO) thin‐film transistors (TFTs) as an active‐matrix backplane. It was found that the fabricated AMOLED display did not suffer from the well‐known pixel non‐uniformity in luminance, even though the simple structure consisting of two transistors and one capacitor was adopted as the unit pixel circuit, which was attributed to the amorphous nature of IGZO semiconductors. The n‐channel a‐IGZO TFTs exhibited a field‐effect mobility of 17 cm²/V‐sec, threshold voltage of 1.1 V, on/off ratio >10⁹, and subthreshold gate swing of 0.28 V/dec. The AMOLED display with a‐IGZO TFT array is promising for large‐sized applications such as notebook PCs and HDTVs because the a‐IGZO semiconductor can be deposited on large glass substrates (larger than Gen 7) using the conventional sputtering system.     

Human tracking and silhouette extraction for human–robot interaction systems

In this study, we propose a new integrated computer vision system designed to track multiple human beings and extract their silhouette with a pan-tilt stereo camera, so that it can assist in gesture and gait recognition in the field of Human–Robot Interaction (HRI). The proposed system consists of three modules: detection, tracking and silhouette extraction. These modules are robust to camera movements, and they work interactively in near real-time. Detection was performed by camera ego-motion compensation and disparity segmentation. For tracking, we present an efficient mean shift-based tracking method in which the tracking objects are characterized as disparity weighted color histograms. The silhouette was obtained by two-step segmentation. A trimap was estimated in advance and then effectively incorporated into the graph-cut framework for fine segmentation. The proposed system was evaluated with respect to ground truth data, and it was shown to detect and track multiple people very well and also produce high-quality silhouettes.