Measurement of mean free paths for inelastic electron scattering of Si and SiO2

The effects of accelerating voltage and collection angle on the mean free path for all inelastic electron scattering (lambdap), which is an important parameter for determining specimen thickness by using electron energy-loss spectroscopy, were investigated with crystalline Si and amorphous SiO2. First, thickness of Si film was measured with the convergent-beam electron diffraction method, while thickness of SiO2 particles was estimated from their spherical shape. Then from electron energy-loss spectra, lambdap was evaluated for Si film and SiO2 particles by changing the accelerating voltage (100 to approximately 300 kV) and the collection angle for the scattered electrons. Under the condition of no objective aperture, lambdap for Si film and SiO2 particles was found to increase with the increase of accelerating voltage and to take values of 180+/-6 nm (Si) and 247+/-8 nm (SiO2) at 300 kV. Also, it was found that lambdap in both cases decreases drastically with the increase of collection angle in the range smaller than 25 mrad, while it tends to take a constant value at the collection angle larger than 25 mrad at 200 kV.     

Point-spread function for a rotationally symmetric birefringent lens

Imaging properties of a birefringent lens, in which the fast (or the slow) axis is distributed in the radial direction whereas magnitude of birefringence varies as a quadratic function of the pupil radius, are investigated by calculating a point-spread function. It is found that the point image is analytically described by using the Lommel function as well as the zero-order Bessel function, and a localized intensity null surrounded by bright regions in all directions can be realized at a geometrical focus under certain conditions. The magnitude of birefringence that is tolerable in image formations is also discussed, assuming that the lens is applied to microlithography.     

Wearable vibrotactile systems for virtual contact and information display

This paper presents a development history of a wearable, scalable vibrotactile stimulus delivery system. This history has followed a path from desktop-based, fully wired systems, through hybrid approaches consisting of a wireless connection from the host computer to a body-worn control box and wires to each tactor, to a completely wireless system employing Bluetooth technology to connect directly from the host to each individual tactor unit. Applications for such a system include delivering vibrotactile contact cues to users of virtual environments, providing directional cues in order to increase situational awareness in both real and virtual environments, and for general information display in wearable contexts. Through empirical study, we show that even a simple configuration, such as eight tactors arrayed around the torso, can be effective in increasing situational awareness in a building-clearing task, compared to users who perform the same task without the added cues.     

Conference assistant system for supporting knowledge sharing in academic communities

This paper describes our ongoing attempts to build a communityware system by presenting a project of providing digital assistants to support participants in an academic conference. We provided participants at the conference with a personal assistant system with mobile and ubiquitous computing technologies and facilitated communication among the participants. We also made online services available via the Web to encourage the participants to continue their relationships even after the conference. In this paper, we show the system we provided for the project and report the results.     

Clonal analysis of a human antibody response. III. Nucleotide sequences of monoclonal IgM, IgG, and IgA to rabies virus reveal restricted V kappa gene utilization, junctional V kappa J kappa and V lambda J lambda diversity, and somatic hypermutation

In previous work, we generated four IgM, five IgG1, and one IgA1 mAbs to rabies virus using B cells from four subjects vaccinated with inactivated rabies virus, a thymus-dependent (TD) mosaic Ag, and sequenced the mAb V(H)DJ(H) genes. Here, we have cloned the V kappa J kappa and V lambda J lambda genes to complete the primary structure of the Ag-binding site of these mAbs. While the anti-rabies virus mAb selection of VA genes (2e.2.2 twice, DPL11, and DPL23) reflected the representation of the V lambda genes in the human haploid genome (stochastic utilization), that of V kappa genes (O2/O12 twice, O8/O18, A3/A19, A27, and L2) did not (p = 0.0018) (nonstochastic utilization). Furthermore, the selection of both V kappa and V lambda genes by the anti-rabies virus mAbs vastly overlapped with that of 557 assorted V kappa J kappa rearrangements, that of 253 V lambda J lambda rearrangements in lambda-type gammopathies, and that of other Abs to thymus-dependent Ags, including 23 anti-HIV mAbs and 51 rheumatoid factors, but differed from that of 43 Abs to Haemophilus influenzae type b polysaccharide, a prototypic thymus-independent (TI) Ag. The anti-rabies virus mAb V kappa J kappa and V lambda J lambda segments displayed variable numbers of somatic mutations, which, in mAb58 and the virus-neutralizing mAb57, entailed a significant concentration of amino acid replacements in the complementarity-determining regions (p = 0.0028 and p = 0.0023, respectively), suggesting a selection by Ag. This Ag-dependent somatic selection process was superimposed on a somatic diversification process that occurred at the stage of B cell receptor for Ag rearrangement, and that entailed V gene 3' truncation and N nucleotide additions to yield heterogeneous CDR3s.     

Modeling Party Support of Japanese Voters in the Early 1996

This article investigates factors that influenced Japanese voters in the early 1996 in determining which political party to support. Proportional-odds model, a model which retains ordinal nature of political hues or ideologies of the Japanese political parties, is fitted to the data. Samples with answers “I do not know” to the questions are treated as missing. The EM algorithm enables us to incorporate the samples with missing-values. We found that determining which party to support is a purely political decision for Japanese voters based solely on their ideologies and attitude towards the current cabinet, not to be influenced by their geographical profiles nor financial situations. Missing-value problem were found not to be ignored in the sense that marginally significant or insignificant explanatory variables can easily turn otherwise when the same model is fitted only for the data with no missing-values.

     

Illumination normalization with time-dependent intrinsic images for video surveillance

Variation in illumination conditions caused by weather, time of day, etc., makes the task difficult when building video surveillance systems of real world scenes. Especially, cast shadows produce troublesome effects, typically for object tracking from a fixed viewpoint, since it yields appearance variations of objects depending on whether they are inside or outside the shadow. In this paper, we handle such appearance variations by removing shadows in the image sequence. This can be considered as a preprocessing stage which leads to robust video surveillance. To achieve this, we propose a framework based on the idea of intrinsic images. Unlike previous methods of deriving intrinsic images, we derive time-varying reflectance images and corresponding illumination images from a sequence of images instead of assuming a single reflectance image. Using obtained illumination images, we normalize the input image sequence in terms of incident lighting distribution to eliminate shadowing effects. We also propose an illumination normalization scheme which can potentially run in real time, utilizing the illumination eigenspace, which captures the illumination variation due to weather, time of day, etc., and a shadow interpolation method based on shadow hulls. This paper describes the theory of the framework with simulation results and shows its effectiveness with object tracking results on real scene data sets.     

Animated interface agent applying atms-based multimodal input interpretation

Two requirements should be met in order to develop a practical multimodal interface system , i . e ., ( 1 ) integration of delayed arrival of data and ( 2 ) elimination of ambiguity in recognition results of each modality . This paper presents an efficient and generic methodology for interpretation of multimodal input to satisfy these requirements . The proposed methodology can integrate delayed - arrival data satisfactorily and efficiently interpret multimodal input that contains ambiguity . In the input interpretation the multimodal interpretation process is regarded as hypothetical reasoning , and the control mechanismof interpretation is formalized by applying the assumption - based truth maintenance system ( ATMS ). The proposed method is applied to an interface agent system that accepts multimodal input consisting of voice and direct indication gesture on a touch display . The systemcommunicates to the user through a human - like interface agent's three - dimensional motion image with facial expressions , gestures , and a synthesized voice .     

Depth from Refraction Using a Transparent Medium with Unknown Pose and Refractive Index

In this paper, we introduce a novel method for depth acquisition based on refraction of light. A scene is captured directly by a camera and by placing a transparent medium between the scene and the camera. A depth map of the scene is then recovered from the displacements of scene points in the images. Unlike other existing depth from refraction methods, our method does not require prior knowledge of the pose and refractive index of the transparent medium, but instead can recover them directly from the input images. By analyzing the displacements of corresponding scene points in the images, we derive closed form solutions for recovering the pose of the transparent medium and develop an iterative method for estimating the refractive index of the medium. Experimental results on both synthetic and real-world data are presented, which demonstrate the effectiveness of the proposed method.