Jaeheung Yoo

Real-Time Elastography in the Evaluation of Diffuse Thyroid Disease: A Study Based on Elastography Histogram Parameters

The purpose of this study was to evaluate the diagnostic performance of quantitative histogram parameters using real-time tissue elastography (RTE) in the diagnosis of patients with diffuse thyroid disease. One hundred and sixteen patients (mean age, 43.7 ± 10.97 y) who had undergone pre-operative staging ultrasonography and RTE were included. For each patient, 11 parameters were obtained from RTE images, from which the elastic index was calculated. Diagnostic performance of the elastic index and that of the 11 parameters on RTE were calculated and compared. Of the 116 patients, 31 had diffuse thyroid disease and 85 had normal thyroid parenchyma. Area under the receiver operating characteristic curve (A(z)) of MEAN (average relative value) elasticity was high (0.737), without significant differences from other elasticity values. Diagnostic performance of the elastic index was higher than the MEAN, A(z) = 0.753, without significance (p = 0.802). In conclusion, RTE using the elastic index was found to have good diagnostic performance and may be useful in the diagnosis and management of patients with diffuse thyroid disease.

Quantitative Evaluation for Differentiating Malignant and Benign Thyroid Nodules Using Histogram Analysis of Grayscale Sonograms

To evaluate the diagnostic value of histogram analysis using grayscale sonograms for differentiation of malignant and benign thyroid nodules.

Evaluation of Underlying Lymphocytic Thyroiditis With Histogram Analysis Using Grayscale Ultrasound Images

The purpose of this study was to evaluate diagnostic performance of histogram analysis using grayscale ultrasound (US) images in the diagnosis of lymphocytic thyroiditis.

Histogram and gray level co-occurrence matrix on gray-scale ultrasound images for diagnosing lymphocytic thyroiditis

The objective of the study was to evaluate whether texture analysis using histogram and gray level co-occurrence matrix (GLCM) parameters can help clinicians diagnose lymphocytic thyroiditis (LT) and differentiate LT according to pathologic grade. The background thyroid pathology of 441 patients was classified into no evidence of LT, chronic LT (CLT), and Hashimotos thyroiditis (HT). Histogram and GLCM parameters were extracted from the regions of interest on ultrasound. The diagnostic performances of the parameters for diagnosing and differentiating LT were calculated. Of the histogram and GLCM parameters, the mean on histogram had the highest Az (0.63) and VUS (0.303). As the degrees of LT increased, the mean decreased and the standard deviation and entropy increased. The mean on histogram from gray-scale ultrasound showed the best diagnostic performance as a single parameter in differentiating LT according to pathologic grade as well as in diagnosing LT.

Ex Vivo Estimation of Photoacoustic Imaging for Detecting Thyroid Microcalcifications

Background The aim of this study was to evaluate the diagnostic utility of PAI at detecting thyroid microcalcifications at 700 nm laser wavelengths. Methods This study included 36 resected samples in 18 patients. To evaluate the PA manifestation of microcalcifications in PAI, gray level histogram and co-occurrence matrix (COM) texture parameters were extracted from the 3 fixed ROI US and PA images, respectively, per sample. We compared the textural parameters obtained from specimen PAIs between samples with punctate microcalcifications on specimen radiography and those without microcalcifications. Results On specimen US, the mean value (2748.4±862.5) of samples with microcalcifications on specimen radiography was higher than that (1961.9±780.2) of those without microcalcifications (Pu200a=u200a0.007). However, there were no significant differences in textural parameters obtained from specimen PAIs between samples with punctate microcalcifications on specimen radiography and those without when applying both the mean value of the three slices of thyroid specimens and the value of the thyroid specimen slice which had the highest value of the mean values in specimen US. Conclusion PAI did not show significant PA contrast on thyroid microcalcifications indicating that the experimental setup and protocols should be enhanced, e.g., method of complete blood rejection from ex vivo specimens, the multi-wavelength spectroscopic PA imaging method which can solely extract the PA signal from microcalcifications even with high spectral interferences, or PA imaging with narrower slice thickness using 2-dimensional array transducer, etc.

Does External Knowledge Sourcing Enhance Market Performance? Evidence from the Korean Manufacturing Industry

Firms continuously search for external knowledge that can contribute to product innovation, which may ultimately increase market performance. The relationship between external knowledge sourcing and market performance is not well-documented. The extant literature primarily examines the causal relationship between external knowledge sources and product innovation performance or to identify factors which moderates the relationship between external knowledge sourcing and product innovation. Non-technological innovations, such as organization and marketing innovations, intervene in the process of external knowledge sourcing to product innovation to market performance but has not been extensively examined. This study addresses two research questions: does external knowledge sourcing lead to market performance and how does external knowledge sourcing interact with a firm’s different innovation activities to enhance market performance. This study proposes a comprehensive model to capture the causal mechanism from external knowledge sourcing to market performance. The research model was tested using survey data from manufacturing firms in South Korea and the results demonstrate a strong statistical relationship in the path of external knowledge sourcing (EKS) to product innovation performance (PIP) to market performance (MP). Organizational innovation is an antecedent to EKS while marketing innovation is a consequence of EKS, which significantly influences PIP and MP. The results imply that any potential EKS effort should also consider organizational innovations which may ultimately enhance market performance. Theoretical and practical implications are discussed as well as concluding remarks.

Use of External Information Sources by Potential Adopters of IT Convergence Products: Focusing on Potential Adopters of Smartphone

In this study, we have examined how the potential users of IT convergence product use the external information sources for purchasing decision focusing on a case of smartphone. Although the specifications and price of IT convergence products, such as smartphone, tablet pc, and smart TV, are considered as major criteria for purchasing decision, the competitiveness of these factors have disappeared as many companies launch similar products in the market. External information sources play a significant role to differentiate the alternatives by offering value-added experience information. The effect of external information sources becomes stronger for experience and high-involvement product whose performance can be evaluated through only users` direct experience. In this study, we categorized the external information sources for smartphone into five; company ads, personal network, expert group, consumers, and media. Through an empirical study with potential smartphone users, we verified how these external information sources affect users` purchasing decision in the perspective of the perceived attributes of information source, quality of information, and individual`s characteristics based on self-regulatory theory.

Understanding makerspace continuance

This study examines makerspace continuance intention using self-determination theory.Technical, economic, and social support enhance a users basic psychological needs.Psychological need fulfillment increases intrinsic motivation. Makerspaces are informal physical spaces located in community settings or educational institutions where people immerse themselves in creative making. Makerspaces hold incredible potential for fostering essential skills needed for the future and are increasing in number worldwide. Previous research has identified many diverse makerspace initiatives and has demonstrated their potential, but few research has examined makerspace sustainability. Makerspace sustainability is a significant issue as diminished participation, activity, utilization, and retention limit its success. This study examines makerspace sustainability by understanding which factors influence makerspace continuance intention. This study proposes and empirically tests a conceptual framework based on self-determination theory to identify the motivations of makerspace users. An analysis of data collected from 121 South Korean makerspace users indicates that makerspace environmental support is significantly related to a makerspace users basic psychological needs. Those psychological needs positively impact intrinsic motivation, which ultimately influences makerspace continuance intention. This research has several implications for academics while recommendations are proposed that have immediate application for practitioners which are informed by the study results.

Investigation on Key Success Factors for Future Broadcasting and Telecom Convergence Service Using AHP Method

The competition among companies in converged market of broadcasting and telecommunications has become severe. Companies in this market have vertically integrated critical resources by acquiring or strategically allying with relevant companies. However, the expansion of business territory accompanies financial, organizational, and technological risks. As such, it is important to identify critical success factors that highly affect the companys competency. This study is aimed at delivering strategic implications for firms playing in the converged market of broadcasting and telecommunications by drawing the priorities of competitive resources to acquire. To do this, we selected four teen specific core resources on CPNT (content- platform - network - terminal) value chain. Then, we conducted an Analytic Hierarchical Process (AHP) using data from experts in this industry. As a result, the priority for acquisition of competitive resources is presented as follows: broadcasting programs, implementation of TV application store, multi-platform, investment on wireless network, and diffusion of mobile devices. In addition, the result shows that the platform-centric vertical integration is the most promising strategy for competition.