Performance Optimization of IPN in RF PLL using Bayesian Optimization

Ji-Sub Yoon,Doing-In Choi,Seung Young Park,In-Chul Hwang 대한전자공학회 2024 Journal of semiconductor technology and science Vol.24 No.2

The performance optimization of a circuit in a short time is one of the important issues for IC testing. Traditional methods depend on domain knowledge and exhaustive search (ES) for feasible parameters. In this paper, we proposed the sub-optimal control of the integrated phase noise (IPN) characteristics of RF phase lock loop (PLL) using a Bayesian optimization. For data acquisition, we designed an autonomous measurement platform based on general purpose interface bus (GPIB) and Python. Using our algorithm, we achieved performance within around 3 dB of the optimal at the 95th percentile and reduced the search time for optimal parameters by at least 98.75% compared to the ES method.

Bayesian Optimization을 활용한 RF PLL의 IPN 특성 최적화 방안 연구

윤지섭(Ji-Sub Yoon),김정훈,황인철(In-Chul Hwang),박승영(Seungyoung Park) 대한전자공학회 2022 대한전자공학회 학술대회 Vol.2022 No.11

In this paper, we proposed the sub-optimal control of the IPN characteristics of RF PLLs using Bayesian optimization. Specifically, a GPIB interface using Python and a phase noise analyzer were used to acquire the measurement data of IPN from a DUT board. From the results, we observed that the number of measurements can be reduced by 95% while achieving 94.2% of the optimal performance.

여행업 종사원의 데이터베이스 마케팅 인식에 관한 연구

이윤섭,박지홍 문화관광연구학회 2001 문화관광연구 Vol.3 No.3

The purpose of this study is to present some desirables to build relationship with customer of Travel agency. In the future, the success and failure of travel agencies have to achieve effectively the corporate goals, positively coping with the corporate environmental changes in the transformation of the professional management system with the strong international responsiveness. In this respect, They have to concentrate on the customers focused on the environments and give the priority of customer's satisfaction in the process of carrying out the management. In travel agency management the importance of travel agency must be evaluated to form, develope and maintain building relationship with customer. It is possible for customer database marketing to attain the aim of marketing thru every activity by the stage of building relationship with customer, keeping relationship with customer, and interest maximization of both travel agency and customer.

RAW264.7 세포에서 interferon-r 및 LPS에 의해 유도되는 NO생성에 미치는 TALT-35의 영향

박종일,박경석,김종석,박지훈,윤은진,송경섭,서강식,김훈,윤완희,박승길,임규,황병두 충남대학교 생물공학연구소 2006 생물공학연구지 Vol.12 No.-

TALP-35 purified from human term placenta is known to increase microtubule polymerization and stabilize the polymerized microtubule. To examine the effect of TALP-35 on immune system this study was performed. MTT assay was performed to investigate the effect of TALP-35 on the proliferation of RAW264.7 cells. TALP-35 dose dependently suppress the proliferation of RAW264.7 cells at high concentration (above 1 μM) in unstimulated cells, in case of 10 μM TALP-35 treated cells the suppression was 25% but in stimulated cells it was only 15%. Cosedimentation assay was carried out to investigate whether TALP-35 can bind to tubulin of RAW264.7, monocyte/macrophage lineage of mouse, and polymerize it. TALP-35 polymerize the tubulin of RAW264.7 cells and sedimented in dose-dependent manner. To investigate the effect of TALP-35 on the expression of iNOS protein western blotting was performed. The expression level of iNOS was decreased dose dependently in high concentration of TALP-35 treatment. To examine the activity of iNOS, secreted NO was determined by method based on Griess reaction. Interferon-γ and LPS-stimulated production of NO from RAW264.7 cells was decreased dose dependently above 0.1 μM concentration of TALP-35 and 50% is decreased at 10μM of it. This study shows TALP-35 can control cytokine induced-iNOS expression therefore it might control inflammatory diseases.

손마사지가 허혈성 심질환 환자의 불안에 미치는 효과

현경선,이향련,공송심,윤경자,김현섭,김효남,최지원,김운정 성인간호학회 2001 성인간호학회지 Vol.13 No.2

The purpose of this study was to investigate the effect of a hand massage program on anxiety, vital sign and pain in clients with ischemic heart disease. The design utilized for this stuffy was quail-experimental with a nonequivalent control group non-synchronized design The subjects were fifty-four patients, twenty-eight for the experimental and twenty-six for the control group, who were admitted with ischemic heart diease at a cardiac intensive care unfit in K medical center of K university. This study was carried out from May, 1999 to March, 2000. The level of anxiety and pain measured by Visual Analogue Scale, systolic blood pressure, diastolic blood pressure and pulse rate were measured before and after hand massage, the state of Anxiety was measured by the Spielberger (1970) scale at admission and after hand massage for three days. The collected data were processed by using the SPSS PC program and analyzed using χ2-test and t-test. The result of this study are as follows : 1. The scores of VAS anxiety and State of anxiety of the experimental group were lower than those of the control group. 2. The degree of systolic blond pressure, diastolic blood pressure and pulse rate of the experimental group were lower than that of the control group. 3. The score of VAS pain of the experimental group was lower than that of the control group. The results suggested that hand massage can decrease VAS anxiety, State of anxiety, vital signs and VAS pain of patients who were admitted with ischemic heart disease at cardiac intensive care unit Therefore, It Is proposed that hand massage is an appropriate nursing intervention to relieve anxiety of the patients who were admitted with ischemic heart disease at a cardiac intensive care unit.

Prediction of Decompensation and Death in Advanced Chronic Liver Disease Using Deep Learning Analysis of Gadoxetic Acid-Enhanced MRI

Heo Subin,이승수,Kim So Yeon,Lim Young-Suk,Park Hyo Jung,Yoon Jee Seok,Suk Heung-Il,Sung Yu Sub,Park Bumwoo,Lee Ji Sung 대한영상의학회 2022 Korean Journal of Radiology Vol.23 No.12

Objective: This study aimed to evaluate the usefulness of quantitative indices obtained from deep learning analysis of gadoxetic acid-enhanced hepatobiliary phase (HBP) MRI and their longitudinal changes in predicting decompensation and death in patients with advanced chronic liver disease (ACLD). Materials and Methods: We included patients who underwent baseline and 1-year follow-up MRI from a prospective cohort that underwent gadoxetic acid-enhanced MRI for hepatocellular carcinoma surveillance between November 2011 and August 2012 at a tertiary medical center. Baseline liver condition was categorized as non-ACLD, compensated ACLD, and decompensated ACLD. The liver-to-spleen signal intensity ratio (LS-SIR) and liver-to-spleen volume ratio (LS-VR) were automatically measured on the HBP images using a deep learning algorithm, and their percentage changes at the 1-year follow-up (ΔLS-SIR and ΔLS-VR) were calculated. The associations of the MRI indices with hepatic decompensation and a composite endpoint of liver-related death or transplantation were evaluated using a competing risk analysis with multivariable Fine and Gray regression models, including baseline parameters alone and both baseline and follow-up parameters. Results: Our study included 280 patients (153 male; mean age ± standard deviation, 57 ± 7.95 years) with non-ACLD, compensated ACLD, and decompensated ACLD in 32, 186, and 62 patients, respectively. Patients were followed for 11–117 months (median, 104 months). In patients with compensated ACLD, baseline LS-SIR (sub-distribution hazard ratio [sHR], 0.81; p = 0.034) and LS-VR (sHR, 0.71; p = 0.01) were independently associated with hepatic decompensation. The ∆LS-VR (sHR, 0.54; p = 0.002) was predictive of hepatic decompensation after adjusting for baseline variables. ∆LS-VR was an independent predictor of liver-related death or transplantation in patients with compensated ACLD (sHR, 0.46; p = 0.026) and decompensated ACLD (sHR, 0.61; p = 0.023). Conclusion: MRI indices automatically derived from the deep learning analysis of gadoxetic acid-enhanced HBP MRI can be used as prognostic markers in patients with ACLD.

SnO₂-Coated 3D Etched Cu Foam for Lithium-ion Battery Anode

Um, Ji Hyun,Kim, Hyunwoo,Cho, Yong-Hun,Yoon, Won-Sub The Korean Electrochemical Society 2020 Journal of electrochemical science and technology Vol.11 No.1

SnO₂-based high-capacity anode materials are attractive candidate for the next-generation high-performance lithium-ion batteries since the theoretical capacity of SnO₂ can be ideally extended from 781 to 1494 mAh g^-1. Here 3D etched Cu foam is applied as a current collector for electron path and simultaneously a substrate for the SnO₂ coating, for developing an integrated electrode structure. We fabricate the 3D etched Cu foam through an auto-catalytic electroless plating method, and then coat the SnO₂ onto the self-supporting substrate through a simple sol-gel method. The catalytic dissolution of Cu metal makes secondary pores of both several micrometers and several tens of micrometers at the surface of Cu foam strut, besides main channel-like interconnected pores. Especially, the additional surface pores on etched Cu foam are intended for penetrating the individual strut of Cu foam, and thereby increasing the surface area for SnO₂ coating by using even the internal of Cu foam. The increased areal capacity with high structural integrity upon cycling is demonstrated in the SnO₂-coated 3D etched Cu foam. This study not only prepares the etched Cu foam using the spontaneous chemical reactions but also demonstrates the potential for electroless plating method about surface modification on various metal substrates.

Phase Dynamics on Conversion-Reaction-Based Tin-Doped Ferrite Anode for Next-Generation Lithium Batteries

Um, Ji Hyun,Palanisamy, Kowsalya,Jeong, Mihee,Kim, Hyunchul,Yoon, Won-Sub American Chemical Society 2019 ACS NANO Vol.13 No.5

<P>The conventional view of conversion reaction is based on the reversibility, returning to an initial material structure through reverse reaction at each cycle in cycle life, which impedes the complete understanding on a working mechanism upon a progression of cycles in conversion-reaction-based battery electrodes. Herein, a series of tin-doped ferrites (Fe<SUB>3-<I>x</I></SUB>Sn<SUB><I>x</I></SUB>O<SUB>4</SUB>, <I>x</I> = 0-0.36) are prepared and applied to a lithium-ion battery anode. By achieving the ideal reoxidation into SnO<SUB>2</SUB>, the Fe<SUB>2.76</SUB>Sn<SUB>0.24</SUB>O<SUB>4</SUB> composite anchored on reduced graphene oxide shows a high reversible capacity of 1428 mAh g<SUP>-1</SUP> at 200 mA g<SUP>-1</SUP> after 100 cycles, which is the best performance of Sn-based anode materials so far. Significantly, a newly formed γ-FeOOH phase after 100 cycles is identified from topological features through synchrotron X-ray absorption spectroscopy with electronic and atomic structural information, suggesting the phase transformation from magnetite to lepidocrocite upon cycling. Contrary to the conventional view, our work suggests a variable working mechanism in an iron-based composite with the dynamic phases from iron oxide to iron oxyhydroxide in the battery cycle life, based on the reactivity of metal nanoparticles formed during reaction toward the solid electrolyte interface layer.</P> [FIG OMISSION]</BR>

Enhancement of the interfacial reaction on mesoporous RuO₂ for next generation Li batteries

Kim, Yunok,Yoon, Jeasang,Park, Gwi Ok,Park, Su Bin,Kim, Hyunchul,Kim, Ji Man,Yoon, Won-Sub Elsevier 2018 Journal of Power Sources Vol.396 No.-

<P><B>Abstract</B></P> <P>In order to develop high energy density Li rechargeable batteries, nano-sized materials have attracted attention as the active materials. Mesoporous materials consist of the micrometre-sized particles, and they have high surface area due to their mesopore and thin wall thickness of framework. Here, we synthesize a highly ordered mesoporous RuO<SUB>2</SUB> to investigate the effect that the mesoscopic structure has on the capacity and their corresponding reaction mechanism of Li rechargeable battery. The synthesized mesoporous RuO<SUB>2</SUB> shows an initial discharge capacity of 1366 mAh g<SUP>−1</SUP> on mesoporous RuO<SUB>2</SUB>, which is higher than that of commercial RuO<SUB>2</SUB>. Our findings <I>via In situ</I> X-ray analysis techniques combined with electrochemical analysis demonstrate that the additional capacity of mesoporous RuO<SUB>2</SUB> is resulted from the enhanced interfacial reaction between Ru metal and Li<SUB>2</SUB>O formed by conversion reaction of RuO<SUB>2</SUB>. Nano-size effects of mesoporous structure such as high surface area, easy electron transport, and small domain would enable to improve the interfacial reaction of highly ordered mesoporous RuO<SUB>2</SUB>. The understanding of this relationship between structural engineering and electrochemical properties provides the insight into development of high energy density anode materials in next generation Li rechargeable battery.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mesoporous RuO<SUB>2</SUB> shows higher discharge capacity than that of commercial RuO<SUB>2</SUB>. </LI> <LI> The larger capacity of mesoporous RuO<SUB>2</SUB> is due to the enhanced interfacial reaction. </LI> <LI> Nano-size effects enable to improve the interfacial reaction. </LI> </UL> </P>

Fe₃O₄ nanoparticles encapsulated in one-dimensional Li₄Ti₅O₁₂ nanomatrix: An extremely reversible anode for long life and high capacity Li-ion batteries

Jo, Mi Ru,Jung, Jaepyeong,Lee, Gi-Hyeok,Kim, Yunok,Song, Kyeongse,Yang, Junghoon,Chae, Ji Su,Roh, Kwang Chul,Kim, Yong-Il,Yoon, Won-Sub,Kang, Yong-Mook Elsevier 2016 Nano energy Vol.19 No.-

<P><B>Abstract</B></P> <P>Transition metal oxides are very promising electrode materials for lithium-ion batteries that operate through conversion reactions. Energy densities for conversion reactions are higher than for intercalation reactions, but most of transition metal oxides show poor cycling performance and reversibility due to the pulverization of active materials and subsequent volume changes. We here report a facile and scalable synthesis for realizing Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB>-coated Fe/Fe<SUB>3</SUB>O<SUB>4</SUB> hybrid nanocomposites in the form of one-dimensional nanofibers (C@Fe-Fe<SUB>3</SUB>O<SUB>4</SUB>/Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB> hybrid NFs). This is a new class of highly-reversible and safe anode material that can significantly reduce the lithium-ion diffusion length and improve strain tolerance during Li ion insertion/extraction. Its oxidation state was also impressively controlled through a carbothermal reaction during annealing. The precise oxidation state control of C@Fe-Fe<SUB>3</SUB>O<SUB>4</SUB>/Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB> hybrid NFs simultaneously enabled high capacity due to the conversion reaction of Fe<SUB>3</SUB>O<SUB>4</SUB> as well as high reversibility and stability resulting from zero-strain characteristics and superb kinetics of Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB>. This new electrode material appears promising for not only future energy systems but also various electronic devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> C@Fe-Fe<SUB>3</SUB>O<SUB>4</SUB>/Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB> hybrid NFs showed extremely stable cyclic retention, which enabled to realize a full cell based on transition metal oxides anode for the first time. </LI> <LI> Its mechanical flexibility, electric conductivity and thermal stability were surprisingly enhanced. </LI> <LI> This enhancement was attributed to zero-strain feature of Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB>, and the evolution of Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12-δ</SUB> and metallic Fe. </LI> <LI> This novel hybrid composites showed a synergistic effect thanks to high capacity of Fe<SUB>3</SUB>O<SUB>4</SUB>, high thermal and structural stability of Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB>, and the improved kinetics from dexterous oxidation state and morphology control. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>An effective strategy to significantly boost the structural stability and electrochemical performance of Fe<SUB>3</SUB>O<SUB>4</SUB> nanoparticles through the embedment in Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB> nanomatrix was successfully demonstrated despite its extremely irreversible conversion reaction. The resultant C@Fe-Fe<SUB>3</SUB>O<SUB>4</SUB>/Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB> hybrid NFs showed excellent mechanical flexibility and electronic conductivity that could be each assigned to high stability or zero-strain feature of Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB>, and the evolution of oxygen-deficient Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12-δ</SUB> as well as metallic Fe</P> <P>[DISPLAY OMISSION]</P>