https://oak.chosun.ac.kr/handle/2020.oak/18753 Thu, 30 Oct 2025 00:49:10 GMT 2025-10-30T00:49:10Z https://oak.chosun.ac.kr/handle/2020.oak/18776 Title: Asymmetrical Volume Loss in Hippocampal Subfield During the Early Stages of Alzheimer Disease : A Cross Sectional Study Author(s): Balaji Kannappan Abstract: Hippocampal atrophy is a well-established imaging biomarker of Alzheimer disease (AD). However, hippocampus is a non-homogenous structure with cytoarchitecturally and functionally distinct sub-regions or subfield, with each region performing distinct functions. Certain regions of the subfield have shown selective vulnerability to AD. Here, we are interested in studying the effects of normal aging and mild cognitive impairment on these sub-regional volumes. With a reliable automated segmentation technique, we segmented these subregions of the hippocampus in 101 cognitively normal (CN), 135 early mild cognitive impairment (EMCI), 67 late mild cognitive impairment (LMCI) and 48 AD subjects. Thereby, dividing the hippocampus into hippocampal tail (tail), subiculum (SUB), cornu ammonis 1 (CA1), hippocampal fissure (fissure), presubiculum (PSUB), parasubiculum (ParaSUB), molecular layer (ML), granule cells/molecular layer/ dentate gyrus (GCMLDG), cornu ammonis 3(CA3), cornu ammonis 4(CA4), fimbria and hippocampal-amygdala transition area (HATA). In this cross sectional study of 351 ADNI subjects, no differences in terms of age, gender, and years of education were observed among the groups. Though, the groups had statistically significant differences (p < 0.05 after the multiple comparison correction) in the Mini-Mental State Examination (MMSE) scores. There was asymmetrical volume loss in the early stages of AD with the left hemisphere showing volume loss in regions that were unaffected in the right hemisphere. Bilateral parasubiculum, right cornu ammonis 1, 3 and 4, right fimbria and right HATA regions did not show any volume loss till the late MCI stages. Our findings suggest that the hippocampal subfield regions are selectively vulnerable to AD and also that these vulnerabilities are asymmetrical especially during the early stages of AD. Sun, 31 Dec 2017 15:00:00 GMT https://oak.chosun.ac.kr/handle/2020.oak/18776 2017-12-31T15:00:00Z https://oak.chosun.ac.kr/handle/2020.oak/18779 Title: Reconsideration of F1 Score as a Performance Measure in Mass Spectrometry-based Metabolomics Author(s): Jaesik Jeong; Han Sol Kim; Shin June Kim Abstract: Over the past decade, mass spectrometry-based metabolomics, especially two dimensional gas chromatography mass spectrometry (GCxGC/TOF-MS), has become a key analytical tool for metabolomics data because of its sensitivity and ability to analyze complex biological or biochemical sample. However, the need to reduce variations within/between experiments has been reported and methodological developments to overcome such problem has long been a critical issue. Along with methodological developments, developing reasonable performance measure has also been studied. Following four numerical measures have been typically used for comparison: sensitivity, specificity, receiver operating characteristic (ROC) curves, and positive predictive value (PPV). However, more recently, such measures are replaced with F1 score in many fields including metabolomics area without any carefulness of its validity. Thus, we want to investigate the validity of F1 score on two examples, with the goal of raising the awareness in choosing appropriate performance comparison measure. We noticed that F1 score itself, as a performance measure, was not good enough. Accordingly, we suggest that F1 score be supplemented with other performance measure such as specificity to improve its validity. Sun, 31 Dec 2017 15:00:00 GMT https://oak.chosun.ac.kr/handle/2020.oak/18779 2017-12-31T15:00:00Z https://oak.chosun.ac.kr/handle/2020.oak/18778 Title: Estimators Shrinking towards Projection Vector for Multivariate Normal Mean Vector under the Norm with a Known Interval Author(s): Hoh Yoo Back Abstract: Consider the problem of estimating a 􀆎 􀁚􀃎 mean vector 􀄾 (􀆎 􀃠 􀆐 􀀾 􀃐), 􀆐 􀃡 􀂙􀂈􀂕􀂒􀃞􀂤 􀃟 with a projection matrix 􀂤 under the quadratic loss, based on a sample 􀂲􀃎 􀃬 􀂲􀃏 􀃬 􀁺 􀃬 􀂲􀆌 . In this paper a James-Stein type estimator with shrinkage form is given when it’s variance distribution is specified and when the norm 􀃧􀃧 􀄾 􀃠 􀂤 􀄾 􀃧􀃧 is constrain, where 􀂤 is an idempotent and symmetric matrix and 􀂙􀂈􀂕􀂒􀃞􀂤􀃟 􀃡 􀆐 . It is characterized a minimal complete class of James-Stein type estimators in this case. And the subclass of James-Stein type estimators that dominate the sample mean is derived. Sun, 31 Dec 2017 15:00:00 GMT https://oak.chosun.ac.kr/handle/2020.oak/18778 2017-12-31T15:00:00Z https://oak.chosun.ac.kr/handle/2020.oak/18777 Title: Development of a Hybrid Recognition System Using Biometrics to Manage Smart Devices based on Internet of Things Author(s): Ilhak Ban; Seonghun Jo; Haneum Park; Junho Um; Se-Jin Kim Abstract: In this paper, we propose a hybrid-recognition system to obtain the state information and control the Internet of Things (IoT) based smart devices using two recognitions. First, we use a facial recognition for checking the owner of the mobile devices, i.e., smartphones, tablet PCs, and so on, and obtaining the state information of the IoT based smart devices, i.e., smart cars, smart appliance, and so on, and then we use a fingerprint recognition to control them. Further, in the conventional system, the message of the state and control information between the mobile devices and smart devices is only exchanged through the cellar mobile network. Thus, we also propose a direct communication to reduce the total transmission time. In addition, we develop a testbed of the proposed system using smartphones, desktop computers, and Arduino vehicle as one of the smart devices. We evaluate the total transmission time between the conventional and direct communications and show that the direct communication with the proposed system has better performance. Sun, 31 Dec 2017 15:00:00 GMT https://oak.chosun.ac.kr/handle/2020.oak/18777 2017-12-31T15:00:00Z