Seasonal Variation of Cosmic Ray Intensity Observed by the Oulu Neutron Monitor

Jaesik Jeong,Suyeon Oh 한국우주과학회 2020 Journal of Astronomy and Space Sciences Vol.37 No.3

Muons and neutrons are representative secondary particles that are generated by interactions between primary cosmic ray particles (mostly protons) and the nuclei of atmospheric gas compounds. Previous studies reported that muons experience seasonal variations because of the meteorological effects of temperature. The intensity of neutrons has a typical modulation with various periods and reasons, such as diurnal and solar variation or transient events. This paper reports that cosmic ray particles, which were observed by neutron monitors, have seasonal variations using the daily data at the Oulu neutron monitor. To eliminate the effects of solar activity across time, the daily data were normalized by two different transformations: transformations with respect to the grand mean and yearly mean. The data after transformation with respect to the yearly mean showed more statistical stability and clear seasonal variations. On the other hand, it is difficult to determine if the seasonal variation results from terrestrial effects, such as meteorological factors, or extraterrestrial effects, such as the position of the Earth in its orbit of revolution.

Reconsideration of F1 Score as a Performance Measure in Mass Spectrometry-based Metabolomics

Jaesik Jeong,Han Sol Kim,Shin June Kim 조선대학교 기초과학연구원 2018 조선자연과학논문집 Vol.11 No.3

Reconsideration of F1 Score as a Performance Measure in Mass Spectrometry-based Metabolomics

Jeong, Jaesik,Kim, Han Sol,Kim, Shin June The Basic Science Institute Chosun University 2018 조선자연과학논문집 Vol.11 No.3

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.

Semi-Local Structure Patterns for Robust Face Detection

Jeong, Kyungjoong,Choi, Jaesik,Jang, Gil-Jin IEEE Signal Processing Society 2015 IEEE signal processing letters Vol. No.

<P>In many image processing and computer vision problems, including face detection, local structure patterns such as local binary patterns (LBP) and modified census transform (MCT) have been adopted in widespread applications due to their robustness against illumination changes. However, being reliant on the local differences between neighboring pixels, they are inevitably sensitive to noise. To overcome the problem of noise-vulnerability of the conventional local structure patterns, we propose semi-local structure patterns (SLSP), a novel feature extraction method based on local region-based differences. The SLSP is robust to illumination variations, distortion, and sparse noise because it encodes the relative sizes of the central region with locally neighboring regions into a binary code. The principle of SLSP leads noise-robust expansions of LBP and MCT feature extraction frameworks. In a statistical analysis, we find that the proposed methods transform a substantial amount of random noise patterns in face images into more meaningful uniform patterns. The empirical results on the <TEX>${\rm MIT} + {\rm CMU}$</TEX> dataset and FDDB (face detection dataset and benchmark) show that the proposed semi-local patterns applied to LBP and MCT feature extraction frameworks outperform the conventional LBP and MCT features in AdaBoost-based face detectors, with much higher detection rates.</P>

Automated Correction of Artifacts in Neural Text-to-Speech Models

Seongyeop Jeong(정성엽),Jaesik Choi(최재식) Korean Institute of Information Scientists and Eng 2023 한국정보과학회 학술발표논문집 Vol.2023 No.12

[미발표] 전동차용 8mH급 철심형 필터리액터의 설계제작 및 특성평가

강재식(Jaesik Kang),이창영(Changyoung Lee),조정민(Jeongmin Jo),이진호(Jinho Lee),정현승(Hyunseung Jeong) 한국철도학회 2013 한국철도학회 학술발표대회논문집 Vol.2013 No.5

본 논문에서는 VVVF 추진 DC 전동차에 공급되는 전원의 품질 향상을 위하여 추진제어장치의 입력단에 설치되는 필터리액터의 경량화를 위한 설계제작 및 특성평가를 수행하였다. 기존에 사용되는 공심형 필터리액터를 대체하여 철심형 필터리액터에 대한 연구를 진행하였다. 요구 사항에 알맞은 구조 및 형상과 성능 조건을 만족하는 필터리액터를 설계하기 위해 유한요소해석 기법을 이용한 전자상 해석과 열 해석을 동시에 진행하였다. 또한 해석에 의한 설계 결과를 검증하기 위해 시작품을 제작하였고, 제시된 필터리액터의 요구 사양에 따른 성능시험을 실시하였다. 자연냉각 조건에서 8.0mH, 정격 DC 450A, DC 1500V를 만족하고, 절연열화시험과 온도상승시험을 진행하여 요구 사양을 만족시켰다. 따라서 510kg의 중량을 갖는 기존 공심형 필터리액터에서 19.6%가 감소된 약 410kg수준에서 제작이 가능하였다. In this paper, design and characteristic evaluation of the filter reactor (FL), which is installed on railway vehicle propulsion control system to maintain the improved power supply, was performed for weight reduction of VVVF DC railway vehicles. Iron-core type filter reactor was replaced a conventional air-core type filter reactor with in this research. In order to design the iron-core FL in a clear structure and proper conditions, the electromagnetic and thermal analysis was progressed by using finite element method (FEM). A prototype was fabricated to verify the result of the design, and some experiments were carried out with respect to certain conditions. With an air-cooled condition, the specifications were satisfied in the conditions of 8mH±10%, rated DC 450A, DC 1500V, and insulating degradation, temperature characteristics as well. As a result, it is possible to fabricate the iron-core type FL with about 410kg weight 19.6% lighter than the conventional air-core FL, which weighs 510kg.

얼굴정렬과 AdaBoost를 이용한 얼굴 표정 인식

정경중(Kyungjoong Jeong),최재식(Jaesik Choi),장길진(Gil-Jin Jang) 대한전자공학회 2014 전자공학회논문지 Vol.51 No.11

Effects of brush-anode configurations on performance and electrochemistry of microbial fuel cells

Kang, Heunggu,Jeong, Jaesik,Gupta, Prabuddha L.,Jung, Sokhee P. Elsevier 2017 International journal of hydrogen energy Vol.42 No.45

<P><B>Abstract</B></P> <P>For practical implementation of MFC, increasing power generation is important because it is closely related with energy production rate and wastewater treatability. However, it is not known which relative arrangement of anode and cathode gives the best performance, and it is necessary to know electrochemical reference point of the brush anode for this. Five different brush-anode configurations were tested in a single-chambered cubic MFC. By merely changing a brush anode configuration, power and current densities were increased by 20% and 30%, respectively. The horizontally-positioned anode configuration (H1) with the closest anode-cathode distance produced the highest power and current. EIS showed that anode impedance and full-cell impedance were decreased by 60% and 49%, respectively. CE and EE were not significantly affected by the anode-cathode distance, but the horizontal type cells showed relatively higher CE, EE and COD removal rate and shorter batch time. The center of a titanium current collector and the center of carbon fibers of a brush-anode were found to be statistically-significant reference points for MFC electrochemistry.</P> <P><B>Highlights</B></P> <P> <UL> <LI> By merely changing anode configuration, P<SUB>max</SUB> increased by 20%. </LI> <LI> By merely changing anode configuration, I<SUB>opt</SUB> increased by 30%. </LI> <LI> Anode impedance and full-cell impedance decreased by 60% and 49%, respectively. </LI> <LI> The horizontal anode with closest electrode distance produced the highest power and current. </LI> <LI> The center of a titanium current collector and the center of carbon fibers were statistically-significant reference points. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

심층 순환 신경망

정경중(Kyungjoong Jeong),최재식(Jaesik Choi) 한국정보과학회 2015 정보과학회지 Vol.33 No.8

Metabotyping of rice (<i>Oryza sativa</i> L.) for understanding its intrinsic physiology and potential eating quality

Song, Eun-Hye,Jeong, Jaesik,Park, Clara Yongjoo,Kim, Han-Yong,Kim, Eun-Hee,Bang, Eunjung,Hong, Young-Shick Elsevier 2018 Food Research International Vol.111 No.-

<P><B>Abstract</B></P> <P>Rice (<I>Oryza sativa</I> L.), the major staple food in many countries, has genetic diversity adapted to different environmental conditions. However, metabolic traits about diverse rice plants are rarely discovered. In the present study, rice leaves and grains were collected at whole growth stages from late (LMC) and early (EMC) maturing cultivars. Metabolic dependences of rice plants on both growth and cultivar were investigated in their leaves and grains through NMR-based metabolomics approach. Rice leaf metabolome were differently regulated between two rice cultivars, thereby affecting variations of rice grain metabolome. Sucrose levels in leaves of EMC were markedly decreased compared to those in LMC, and more accumulations of sucrose, amino acids and free fatty acids were found in grains of EMC. These distinct metabolisms between EMC and LMC rice cultivars were associated with temperature during their growing seasons and might affect the eating quality of rice. The current study highlights that metabolomic approach of rice leaves and grains could lead to better understanding of the relationship between their distinct metabolisms and environmental conditions, and provide novel insights to metabolic qualities of rice grains.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Dependences of rice leaf and grain metabolome on growth and cultivar were found. </LI> <LI> Metabolic variations of rice leaves and grains were associated with temperature. </LI> <LI> Metabolism in rice leaf affects rice grain metabolism. </LI> <LI> Rice grain metabolome could predict eating quality of rice. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>