43 research outputs found
An Empirical Examination of Consumer Behavior for Search and Experience Goods in Sentiment Analysis
With the explosive increase of user-generated content such as product reviews and social media, sentiment analysis has emerged as an area of interest. Sentiment analysis is a useful method to analyze product reviews, and product feature extraction is an important task in sentiment analysis, during which one identifies features of products from reviews. Product features are categorized by product type, such as search goods or experience goods, and their characteristics are totally different. Thus, we examine whether the classification performance differs by product type. The findings show that the optimal threshold varies by product type, and simply decreasing the threshold to cover many features does not guarantee improvement of the classification performance
A Review System Based On Product Features In A Mobile Environment
With the rapid growth of the mobile commerce, firms have been trying to get their online channels optimized for the mobile devices. However, many contents on online shopping sites are still focused on a desktop PC environment. Especially, consumer reviews are difficult to browse and grasp via a mobile device. Usually, it is not helpful to simply reduce the size of fonts or photos to fit to mobile devices without a fundamental transformation of the review presentation. In this study, we suggest a feature-based summarization process of consumer reviews in mobile environment. Further, we illustrate an implementation of the process by applying opinion mining techniques to product reviews crawled from a major shopping site in Korean. Finally, a plan for a controlled laboratory experiment is proposed to validate the effectiveness of the suggested review framework in this study
SUPER MULTI-VIEW NEAR-EYE DISPLAY WITH LED ARRAY AND WAVEGUIDE ILLUMINATION MODULE
A near-eye display includes an array of light sources, a reflective spatial light modulator (SLM) synchronized with the array of light sources and configured to modulate and reflect incident light beams to generate images, display optics configured to project the images generated by the reflective SLM to a userโs eye, and a waveguide between the display optics and the reflective SLM, where the waveguide is configured to guide light beams emitted by the array of light sources and direct the light beams towards the reflective SLM to illuminate the reflective SL
Radial hydride fraction with various rod internal pressures and hydrogen contents for Zr-Nb alloy cladding tube
Hydride reorientation experiments for unirradiated Zr-Nb alloy cladding tubes under multi-axial stress states induced by internal pressurization were performed with peak cladding temperature set to 400 degrees C. Applied internal pressure was held constant during cooling down stage. PROPHET was used to analyze Radial Hydride Fraction (RHF) of tested cladding tubes. The attained RHF behavior for a wide range of rod internal pressure (7.5-18.5 MPa) and hydrogen content (0-1100 wppm) were investigated. Empirical models for RHF with respect to rod internal pressure and hydride contents were developed. Ring com-pression tests (RCTs) were conducted to investigate toughness (strain energy density) change with radial hydride formation. In order to take the multi-axial stress effect into account, rod internal pressure-based regulation is necessary. Hydride reorientation threshold rod internal pressure is-9.32 MPa. The rod in-ternal pressure corresponding to hoop stress of 90 MPa is 11.5 MPa, indicating that hydride reorientation in multi-axially stressed Zircaloy cladding tube occurs at hoop stresses below 90 MPa. The presented thermodynamic model for threshold rod internal pressure gives improved agreement with experimen-tally measured threshold with input the directly measured orientation relationship between 8-hydride and a-Zr.(c) 2022 Elsevier B.V. All rights reserved.N
Aberration correction in holographic displays
Optical aberrations hinder the realization of high-quality near-eye displays. The imperfection of the optical components and the human eye causes image quality degradation. This invited paper introduces two recent works on aberration correction methods in holographic displays. The wave optics-based computer-generated hologram calculation method to correct the optical aberration from the eyepiece of the near-eye display is presented. In addition, the ray tracing-based vision-correcting holographic display for correcting the ocular aberration of the human eye is demonstrated.N
Wide field of view holographic tiled display through axially overlapped holographic projection
Space-bandwidth product in digital holography is defined as a product of spatial dimension and bandwidth of the sampled space. This limitation results in a narrow field of view or a small eye-box in holographic near-eye display. Utilizing additional micro-structured or non-periodic optics is a well-known approach that bypasses this physical constraint. However, these approaches require precise alignment and suffer from low signal-to-noise ratio in the reconstructed holographic image. In this work, we propose a novel prototype of holographic near-eye display with wide field of view achieved by axially overlapped holographic projection. The feasibility of the proposed work is evaluated with simulation and experimental results.N
Integration of relay optics in LED-based reflective off-axis digital holographic microscopy
Digital holography is widely known as one of the techniques reconstructing a depth profile of the object. For digital holography (DH), the light source that has a long coherence length such as laser or laser diode is generally recommended. Recently, digital holographic microscopy (DHM) utilizing light emitting diode (LED) as a light source has attracted attention. However, it has to satisfy certain conditions for LED be utilized in off-axis DHM as it has small coherence length. Due to this fact, the hologram cannot be captured from the other side of a beam splitter. Therefore, we propose an LED-based off-axis reflective DHM that combines a 4-f system that optically relays the field to the sensor plane of charge-coupled device (CCD). We analyze the reason why the sample plane has to be relayed by 4-f system. We provide experimental results to verify the necessity of relay optics in LED-based reflective off-axis DHM.N
Accelerating a spatially varying aberration correction of holographic displays with low-rank approximation
Correction of spatially varying aberrations in holographic displays often requires intractable computational loads. In this Letter, we introduce a low-rank approximation method that decomposes sub-holograms into a small number of modes, thereby reformulating the computer-generated hologram calculation into a summation of a few convolutions. The low-rank approximation is carried out with two different algorithms: the Karhunen-Loeve transform as the optimum solution with respect to the mean-squared error criterion and a novel, to the best of our knowledge, optimization method to provide uniform image quality over the entire field of view. The proposed method is two orders of magnitude faster than the conventional point-wise integration method in our experimental setup, with comparable image quality. 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing AgreementN