Roles of Oxygen Interstitial Defects in Atomic-Layer Deposited InGaZnO Thin Films with Controlling the Cationic Compositions and Gate-Stack Processes for the Devices with Subµm Channel Lengths.

Roles of oxygen interstitial defects located in the In-Ga-Zn-O (IGZO) thin films prepared by atomic layer deposition were investigated with controlling the cationic compositions and gate-stack process conditions. It was found from the spectroscopic ellipsometry analysis that the excess oxygens increased with increasing the In contents within the IGZO channels. While the device using the IGZO channel with an In/Ga ratio of 0.2 did not show marked differences with the variations in the oxidant types during the gate-stack formation, the device characteristics were severely deteriorated with increasing the In/Ga ratio to 1.4, when the Al2O3 gate insulator (GI) was prepared with the H2O oxidants (H2O-Al2O3) due to a higher amount of excess oxygen in the channel. Additionally, during the deposition process of the Al-doped ZnO (AZO) gate electrode (GE) replacing from the indium-tin oxide (ITO) GE, the thermal annealing effect at 180 °C facilitated the passivation of oxygen vacancy and the strengthening of metal-oxygen bonding, which could stabilize the TFT operations. From these results, the gate-stack structure employing O3-processed Al2O3 GI (O3-Al2O3) and AZO GE (OA) was suggested to be most suitable for the device using IGZO channel with a higher In content. On the other hand, the device employing H2O-Al2O3 GI and AZO GE exhibited larger negative shifts of threshold voltage (VTH) under positive-bias-temperature stress (PBTS) condition than the device employing O3- Al2O3 GI and ITO GE due to larger hydrogen contents within the gate stacks. Anomalous negative shifts of VTH were accelerated with increasing the In contents of the IGZO channel. When the channel length of the fabricated device were scaled down to submicrometer regime, the OA gate stacks successfully alleviated the short-channel effects.

Development of a user-friendly training software for pharmacokinetic concepts and models.

Although there are many commercially available training software programs for pharmacokinetics, they lack flexibility and convenience. In this study, we develop simulation software to facilitate pharmacokinetics education. General formulas for time courses of drug concentrations after single and multiple dosing were used to build source code that allows users to simulate situations tailored to their learning objectives. A mathematical relationship for a 1-compartment model was implemented in the form of differential equations. The concept of population pharmacokinetics was also taken into consideration for further applications. The source code was written using R. For the convenience of users, two types of software were developed: a web-based simulator and a standalone-type application. The application was built in the JAVA language. We used the JAVA/R Interface library and the 'eval()' method from JAVA for the R/JAVA interface. The final product has an input window that includes fields for parameter values, dosing regimen, and population pharmacokinetics options. When a simulation is performed, the resulting drug concentration time course is shown in the output window. The simulation results are obtained within 1 minute even if the population pharmacokinetics option is selected and many parameters are considered, and the user can therefore quickly learn a variety of situations. Such software is an excellent candidate for development as an open tool intended for wide use in Korea. Pharmacokinetics experts will be able to use this tool to teach various audiences, including undergraduates.

Relationship between bronchial anthracofibrosis and endobronchial tuberculosis.

BACKGROUND/AIMS: Various pulmonary diseases may be associated with bronchial anthracofibrosis (BAF). Our aim was to identify a relationship between BAF and endobronchial tuberculosis (EBTB). METHODS: In total, 156 patients, diagnosed with EBTB using bronchoscopy, between June 1999 and May 2008, were included. Clinical and bronchoscopic findings between patients with BAF (n = 72, BAF group) and without BAF (n = 84, non-BAF) were analyzed retrospectively. RESULTS: The crude odds ratio (OR) of BAF for EBTB was 8.88 (95% confidence interval, 6.37 to 12.37). On multivariate analysis, adjusting for age, history of biomass smoke exposure, and comorbidities, the most significant independent factor for EBTB was a history of biomass smoke exposure (adjusted OR, 17.471; adjusted p < 0.001). EBTB was more frequent in the right lung, particularly the right middle lobar bronchus, in the BAF group. Actively caseating, edematous-hyperemic, and ulcerative were the major types, with 77 (49%), 33 (21%), and 31 cases (20%), respectively. The BAF group had more ulcerative type, while the non-BAF group had more actively caseating type. The duration of EBTB treatment was similar between the groups. No significant difference was observed in the development of complications during treatment and posttreatment bronchostenosis between the groups. CONCLUSIONS: These findings suggest that BAF may be a risk factor for EBTB and affect the location and morphological type at the time of EBTB development.

IPSILON: incremental parsing for semantic indexing of latent concepts.

A new framework for content-based image retrieval, which takes advantage of the source characterization property of a universal source coding scheme, is investigated. Based upon a new class of multidimensional incremental parsing algorithm, extended from the Lempel-Ziv incremental parsing code, the proposed method captures the occurrence pattern of visual elements from a given image. A linguistic processing technique, namely the latent semantic analysis (LSA) method, is then employed to identify associative ensembles of visual elements, which lay the foundation for intelligent visual information analysis. In 2-D applications, incremental parsing decomposes an image into elementary patches that are different from the conventional fixed square-block type patches. When used in compressive representations, it is amenable in schemes that do not rely on average distortion criteria, a methodology that is a departure from the conventional vector quantization. We call this methodology a parsed representation. In this article, we present our implementations of an image retrieval system, called IPSILON, with parsed representations induced by different perceptual distortion thresholds. We evaluate the effectiveness of the use of the parsed representations by comparing their performance with that of four image retrieval systems, one using the conventional vector quantization for visual information analysis under the same LSA paradigm, another using a method called SIMPLIcity which is based upon an image segmentation and integrated region matching, and the other two based upon query-by-semantic-example and query-by-visual-example. The first two of them were tested with 20,000 images of natural scenes, and the others were tested with a portion of the images. The experimental results show that the proposed parsed representation efficiently captures the salient features in visual images and the IPSILON systems outperform other systems in terms of retrieval precision and distortion robustness.

Subjective evaluation of spatial resolution and quantization noise tradeoffs.

Most full-reference fidelity/quality metrics compare the original image to a distorted image at the same resolution assuming a fixed viewing condition. However, in many applications, such as video streaming, due to the diversity of channel capacities and display devices, the viewing distance and the spatiotemporal resolution of the displayed signal may be adapted in order to optimize the perceived signal quality. For example, at low bitrate coding applications an observer may prefer to reduce the resolution or increase the viewing distance to reduce the visibility of the compression artifacts. The tradeoff between resolution/viewing conditions and visibility of compression artifacts requires new approaches for the evaluation of image quality that account for both image distortions and image size. In order to better understand such tradeoffs, we conducted subjective tests using two representative still image coders, JPEG and JPEG 2000. Our results indicate that an observer would indeed prefer a lower spatial resolution (at a fixed viewing distance) in order to reduce the visibility of the compression artifacts, but not all the way to the point where the artifacts are completely invisible. Moreover, the observer is willing to accept more artifacts as the image size decreases. The subjective test results we report can be used to select viewing conditions for coding applications. They also set the stage for the development of novel fidelity metrics. The focus of this paper is on still images, but it is expected that similar tradeoffs apply to video.

Multidimensional incremental parsing for universal source coding.

A multidimensional incremental parsing algorithm (MDIP) for multidimensional discrete sources, as a generalization of the Lempel-Ziv coding algorithm, is investigated. It consists of three essential component schemes, maximum decimation matching, hierarchical structure of multidimensional source coding, and dictionary augmentation. As a counterpart of the longest match search in the Lempel-Ziv algorithm, two classes of maximum decimation matching are studied. Also, an underlying behavior of the dictionary augmentation scheme for estimating the source statistics is examined. For an m-dimensional source, m augmentative patches are appended into the dictionary at each coding epoch, thus requiring the transmission of a substantial amount of information to the decoder. The property of the hierarchical structure of the source coding algorithm resolves this issue by successively incorporating lower dimensional coding procedures in the scheme. In regard to universal lossy source coders, we propose two distortion functions, the local average distortion and the local minimax distortion with a set of threshold levels for each source symbol. For performance evaluation, we implemented three image compression algorithms based upon the MDIP; one is lossless and the others are lossy. The lossless image compression algorithm does not perform better than the Lempel-Ziv-Welch coding, but experimentally shows efficiency in capturing the source structure. The two lossy image compression algorithms are implemented using the two distortion functions, respectively. The algorithm based on the local average distortion is efficient at minimizing the signal distortion, but the images by the one with the local minimax distortion have a good perceptual fidelity among other compression algorithms. Our insights inspire future research on feature extraction of multidimensional discrete sources.