Effective Multiplexing Method for Conditional Access System in Terrestrial DMB

YongHoon Lee,Gwangsoon Lee,Jinhwan Lee,Soo In Lee,김남 한국전자통신연구원 2008 ETRI Journal Vol.30 No.6

This letter proposes a conditional access system (CAS) suitable for use in terrestrial digital multimedia broadcasting (T-DMB), based on an effective multiplexing method to provide encrypted T-DMB services. Specifically, the proposed multiplexing method for a CAS is designed to reduce the additional bit rate while assuring easy access to the designated encrypted services. Finally, the performance of the implemented CAS is confirmed through implementation and a broadcasting experiment under various service environments.

Multiple phase transitions in block copolymer blends and pressure effects on these transitions

Lee, Yonghoon,Jo, Seongjun,Lee, Wooseop,Lee, Hoyeon,Han, Young Soo,Ryu, Du Yeol Elsevier 2017 Polymer Vol.112 No.-

<P><B>Abstract</B></P> <P>We sought to identify an evident enthalpic-driven transition below an entropic-driven closed-loop phase transition by studying the phase behavior in miscible binary block copolymer (BCP) blends of a polystyrene-<I>b</I>-poly (<I>n</I>-butyl methacrylate) (PS-<I>b</I>-P<I>n</I>BMA) and a deuterated polystyrene-<I>b</I>-poly (<I>n</I>-hexyl methacrylate) (<I>d</I>PS-<I>b</I>-P<I>n</I>HMA), using small-angle x-ray scattering (SAXS) and depolarized light scattering (DPLS). Intriguingly, an order-to-disorder transition (ODT) below the closed-loop transition consisting of a lower disorder-to-order transition (LDOT) and an upper order-to-disorder transition (UODT) was observed in the BCP blends of an asymmetric (PS-rich) PS-<I>b</I>-P<I>n</I>BMA and a symmetric <I>d</I>PS-<I>b</I>-P<I>n</I>HMA. Multiple phase transitions, previously undiscovered in BCP system, were attributed to a delicate balance in the free energy of the dispersive intermolecular interactions, the entropic compressibility, and the combinatorial entropy of mixing at an experimental temperature range between the glass transition temperature (<I>T</I> <SUB>g</SUB>) and degradation temperature (<I>T</I> <SUB>d</SUB>). We also characterized the effects of hydrostatic pressure on the transition temperatures to determine the thermodynamic origins of each phase transition.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Phase behavior in miscible binary BCP blends of weakly interacting PS-<I>b</I>-P<I>n</I>BMA/<I>d</I>PS-<I>b</I>-P<I>n</I>HMA. </LI> <LI> Multiple phase transitions displaying an ODT to a LDOT and an UODT (in the closed-loop transition) upon heating. </LI> <LI> 3D phase transition diagram of the BCP blends based on transition behavior. </LI> <LI> Pressure effects on the transition temperatures to evaluate the pressure coefficient (<I>dT/dP</I>). </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

High Gain and Wide Range Time Amplifier Using Inverter Delay Chain in SR Latches

LEE, Jaejun,LEE, Sungho,SONG, Yonghoon,NAM, Sangwook The Institute of Electronics, Information and Comm 2009 IEICE transactions on electronics Vol.92 No.12

<P>This paper presents a time amplifier design that improves time resolution using an inverter chain delay in SR latches. Compared with the conventional design, the proposed time amplifier has better characteristics such as higher gain, wide range, and small die size. It is implemented using 0.13µm standard CMOS technology and the experimental results agree well with the theory.</P>

Performance analysis of OBS networks using the effective bandwidth method

Lee, Yonggyu,Choi, Yonghoon,Lee, Seungjin,Choi, Jun Kyun Springer-Verlag 2011 PHOTONIC NETWORK COMMUNICATION Vol.21 No.2

Tandem laser-induced breakdown spectroscopy laser-ablation inductively-coupled plasma mass spectrometry analysis of high-purity alumina powder

Yonghoon Lee,Hyang Kim 한국분석과학회 2019 분석과학 Vol.32 No.4

Alumina is one of the most important ceramic materials because of its useful physical and chemical properties. Recently, high-purity alumina has been used in various industrial fields. This leads to increasing demand for reliable elemental analysis of impurities in alumina samples. However, the chemical inertness of alumina makes the sample preparation for conventional elemental analysis a tremendously difficult task. Herein, we demonstrated the feasibility of laser ablation for effective sampling of alumina powder. Laser ablation performs sampling rapidly without any chemical reagents and also allows simultaneous optical emission spectroscopy and mass spectrometry analyses. For six alumina samples including certified reference materials and commercial products, laser-induced breakdown spectroscopy (LIBS) and laser-ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) analyses were performed simultaneously based on a common laser ablation sampling. LIBS was found to be useful to quantify alkali and alkaline earth metals with limits-ofdetection (LODs) around 1 ppm. LA-ICP-MS could quantify transition metals such as Ti, Cu, Zn, and Zr with LODs in the range from a few tens to hundreds ppb.

The Efficacy and Safety of GCWB104 (Flos Lonicera Extract) in Functional Dyspepsia: A Single-Center, Randomized, Double-Blind, Placebo-Controlled Study

Yonghoon Choi,Nayoung Kim,Gi Tark Noh,Ju Yup Lee,Dong Ho Lee 거트앤리버 소화기연관학회협의회 2020 Gut and Liver Vol.14 No.1

Background/Aims: The Flos Lonicera extract GCWB104 has been shown to have significant protective effects against gastritis and gastric ulcers in vivo. The aim of this study was to investigate the efficacy and safety of GCWB104 in subjects with functional dyspepsia (FD). Methods: In this single-center, double-blind, randomized clinical trial, 92 subjects diagnosed with FD using the Rome III criteria were allocated to either the test group (300 mg of GCWB104, containing 125 mg of Flos Lonicera extract, twice daily) or the placebo group (300 mg placebo, twice daily). The total score improvement on the Gastrointestinal Symptom Rating Scale (GSRS) for individual symptoms, changes in antioxidant levels, changes in dyspepsia-related quality of life according to the Nepean Dyspepsia Index (NDI), and adverse effects were compared before and after 8 weeks of treatment. Results: The differences in total GSRS scores and score improvements after 8 weeks of treatment were significant between the GCWB104 and control groups (p=0.0452 and p=0.0486, respectively). Thirteen of 15 individual symptoms on the GSRS improved in the GCWB104 group, while six symptoms improved in the control group. In addition, statistically significant changes in rumbling, loose stool, and stool urgency were observed in the GCWB104 group. Blood 8-hydroxy-2’-deoxyguanosine (8-OHdG) levels, known as antioxidants, showed significant reductions after 8 weeks of administration of GCWB104. There were no adverse events related to treatment with GCWB104. Conclusions: GCWB104 safely contributed to improvements in mild to moderate FD and irritable bowel syndrome symptoms. Antioxidant effects of GCWB104 were also suggested (Clinicaltrials.gov number NCT04008901).

Differential-To-Common-Mode Conversion Suppression Using Mushroom Structure on Bent Differential Transmission Lines

Lee, Seungjin,Lim, Jaehyuk,Oh, Sangyeol,Kim, Yonghoon,Oh, Dan,Lee, Jaehoon IEEE 2019 IEEE transactions on components, packaging, and ma Vol.9 No.4

<P>In this paper, we propose a method to suppress differential-to-common-mode conversion noise from right-angle bent differential lines by installing a mushroom structure on the narrow inner line. We assessed the mode conversion noise suppression characteristics of the proposed structure by analyzing dispersion diagrams. The proposed structure exhibits differential-to-common-mode conversion ( <TEX>$S_{cd21}$</TEX>) below −20 dB up to 6 GHz, while <TEX>$S_{cd21}$</TEX> of conventional right-angle bent differential lines is only maintained below −20 dB for frequencies up to 1.04 GHz. In addition, we suggest that further enhancements of the mode conversion suppression bandwidth can be achieved by installing multiple distributed mushroom structures on right-angle bent differential lines. The use of multiple distributed mushrooms enabled us to achieve a wider frequency bandwidth by compensating more fully for the phase difference between the inner and outer lines. Therefore, the right-angle bent differential lines with multiple distributed mushrooms can suppress mode conversion noise under −20 dB up to 10 GHz. We assessed the performance of our proposed structure by conducting measurements in both the frequency and time domains. We obtained a good agreement between our experimental and numerical results. In addition, we measured eye diagrams to demonstrate that the proposed structures suppress differential-to-common-mode conversion noise without degrading the differential signaling quality.</P>

Soft Independent Modeling of Class Analogy (SIMCA) Modeling of Laser-Induced Plasma Emission Spectra of Edible Salts for Accurate Classification

Lee, Yonghoon,Han, Song-Hee,Nam, Sang-Ho SAGE Publications 2017 APPLIED SPECTROSCOPY Vol.71 No.9

<P>We report soft independent modeling of class analogy (SIMCA) analysis of laser-induced plasma emission spectra of edible salts from 12 different geographical origins for their classification model. The spectra were recorded by using a simple laser-induced breakdown spectroscopy (LIBS) device. Each class was modeled by principal component analysis (PCA) of the LIBS spectra. For the classification of a separate test data set, the SIMCA model showed 97% accuracy in classification. An additional insight could be obtained by comparing the SIMCA classification result with that of partial least squares discriminant analysis (PLS-DA). Different from SIMCA, the PLS-DA classification accuracy seems to be sensitive to addition of new sample classes to the whole data set. This indicates that the individual modeling approach (SIMCA) can be an alternative to global modeling (PLS-DA), particularly for the classification problems with a relatively large number of sample classes.</P>

Tandem laser-induced breakdown spectroscopy laser-ablation inductively-coupled plasma mass spectrometry analysis of high-purity alumina powder

Lee, Yonghoon,Kim, Hyang The Korean Society of Analytical Science 2019 분석과학 Vol.32 No.4

Alumina is one of the most important ceramic materials because of its useful physical and chemical properties. Recently, high-purity alumina has been used in various industrial fields. This leads to increasing demand for reliable elemental analysis of impurities in alumina samples. However, the chemical inertness of alumina makes the sample preparation for conventional elemental analysis a tremendously difficult task. Herein, we demonstrated the feasibility of laser ablation for effective sampling of alumina powder. Laser ablation performs sampling rapidly without any chemical reagents and also allows simultaneous optical emission spectroscopy and mass spectrometry analyses. For six alumina samples including certified reference materials and commercial products, laser-induced breakdown spectroscopy (LIBS) and laser-ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) analyses were performed simultaneously based on a common laser ablation sampling. LIBS was found to be useful to quantify alkali and alkaline earth metals with limits-of-detection (LODs) around 1 ppm. LA-ICP-MS could quantify transition metals such as Ti, Cu, Zn, and Zr with LODs in the range from a few tens to hundreds ppb.

Enthalpic and Volumetric Changes at Phase Transitions of Polystyrene-<i>b</i>-poly(alkyl methacrylate) Copolymers and Their Pressure Dependence

Lee, Dong Hyun,Lee, Hoyeon,Lee, Yonghoon,Kim, Yoonkeun,Ryu, Du Yeol American Chemical Society 2014 Macromolecules Vol.47 No.6

<P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mamobx/2014/mamobx.2014.47.issue-6/ma402535w/production/images/medium/ma-2013-02535w_0006.gif'></P>