Salicylic Acid-Based Organic Dyes Acting as the Photosensitizer for Solar Cells

Hong, Sungjun,Park, Jae-Hyeong,Han, Ah-Reum,Ko, Kwan-Woo,Eom, Jin Hee,Namgoong, Sung Keon,Lo, Alvie S. V.,Gordon, Keith C.,Yoon, Sungho,Han, Chi-Hwan American Scientific Publishers 2016 Journal of nanoscience and nanotechnology Vol.16 No.5

<P>A D-pi-A metal-free organic dye, featuring salicylic acid as a novel acceptor/anchoring unit, has been designed, synthesized and applied to dye-sensitized solar cell. The detailed photophysical, electrochemical, photovoltaic and sensitizing properties of the organic dye were investigated, in addition to the computational studies of the dye and dye-(TiO2)(6) system. A solar cell device using this new organic dye as a sensitizer produced a solar to electric power conversion efficiency (PCE) of 3.49% (J(SC) = 6.69 mAcm(-2), V-OC 0.74 V and ff = 0.70) under 100 mWcm(-2) simulated AM 1.5 G solar irradiation, demonstrating that the salicylic acid-based organic dye is a suitable alternative to currently used organometallic dyes.</P>

Gait Recognition Using Decision-Level Fusion

Sungjun Hong,Heesung Lee,Byungyun Lee,Euntai Kim 대한전자공학회 2010 ICEIC:International Conference on Electronics, Inf Vol.1 No.1

For human identification, in this paper, a gait recognition system adopting decision-level fusion is proposed. The gait sequence obtained from a video camera is partitioned into multiple gait cycles selecting key frames summarizing a single stride. After gait cycle partitioning, the projection of a silhouette image called as a frieze pattern is calculated as a gait feature. To identify individual, the outputs of the nearest neighbor classifiers are fused by majority voting. To demonstrate the validity of the proposed method, the CASIA gait dataset A are used to evaluate the recognition performance.

Sensitivity Analysis of Width Representation for Gait Recognition

Sungjun Hong,Euntai Kim 한국지능시스템학회 2016 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.16 No.2

In this paper, we discuss a gait representation based on the width of silhouette in terms of discriminative power and robustness against the noise in silhouette image for gait recognition. Its sensitivity to the noise in silhouette image are rigorously analyzed using probabilistic noisy silhouette model. In addition, we develop a gait recognition system using width representation and identify subjects using the decision level fusion based on majority voting. Experiments on CASIA gait dataset A and the SOTON gait database demonstrate the recognition performance with respect to the noise level added to the silhouette image.

The Effects of Watching a Virtual Reality (VR) Forest Video on Stress Reduction in Adults

Sungjun Hong,Dawou Joung,Jeongdo Lee,Da-Young Kim,Soojin Kim,Bum-Jin Park 인간식물환경학회 2019 인간식물환경학회지 Vol.22 No.3

This study was conducted to investigate the effects of watching a virtual reality (VR) forest video on stress reduction in adults. Experiments were performed in an artificial climate chamber where temperature, humidity and illumination were controlled. To cause stress in subjects, the subjects were asked to multiply two digit numbers by one digit numbers for two minutes. The subjects then watched a VR forest video for five minutes. During the experiment, the heart rate variability (HRV) and heart rate (HR) of subjects were continuously measured for evaluating their physiological state. After measuring the baseline and watching a VR forest video, their psychological state was evaluated using the profile of mood state (POMS), semantic differential (SD) method, and positive affect and negative affect schedule (PANAS). The results of physiological evaluation after watching a VR forest video showed a decrease in the stress index and HR, an increase in the activity of the parasympathetic nervous system, and the standard deviation of normal to normal RR intervals (SDNN). The results of psychological assessment confirmed that watching a VR forest video induced “comfort”, “natural”, and “soothed” feelings in subjects. In addition, watching a VR forest video decreased “tension-anxiety (T-A)”, “depression-dejection (D)”, “anger-hostility (A-H)”, “fatigue (F)”, “total mood disturbance (TMD)”, and increased “vigor (V)” compared to the base line, and decreased “negative affect” and increased “positive affect.” These results indicate that watching a VR forest video decreases adults’ stress index, stabilizes physiological state, and has a positive impact on psychological state. The findings of this study can serve as a basis or providing forest welfare services to people in the blind spots of forest welfare, and can lay a foundation for the adoption of VR, one of the technologies of the fourth industrial revolution in forestry.

Fusion of Multiple Gait Cycles for Human Identification

Sungjun Hong,Heesung Lee,Euntai Kim 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

In this paper, a gait recognition system fusing multiple gait cycles is presented for human identification.First, the cycle length is estimated by calculating the autocorrelation of the foreground sum signal. After gait cycle partitioning, we extract two kinds of gait feature, gait energy image (GEI) and motion silhouette image (MSI). To identify individual, the outputs of the nearest neighbor classifiers are fused at the abstract level based on majorityvoting. Our proposed system is tested on the CASIA gait dataset A and the SOTON gait database. Compared to previous works, our empirical results show extraordinary performance in terms of correct classification rate.

Nanocrystalline Iron-Ore-Based Catalysts for Fischer-Tropsch Synthesis

Hong, Seok Yong,Park, Ji Chan,Lee, Ho-Tae,Yang, Jung-Il,Hong, SungJun,Jung, Heon,Chun, Dong Hyun American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.2

<P>Nanocrystalline iron ore particles were fabricated by a wet -milling process using an Ultra Apex Mill, after which they were used as raw materials of iron-based catalysts for low-temperature Fischer-Tropsch synthesis (FTS) below 280 degrees C, which usually requires catalysts with a high surface area, a large pore volume, and a small crystallite size. The wet -milling process using the Ultra Apex Mill effectively destroyed the initial crystallite structure of the natural iron ores of several tens to hundreds of nanometers in size, resulting in the generation of nanocrystalline iron ore particles with a high surface area and a large pore volume. The iron-ore-based catalysts prepared from the nanocrystalline iron ore particles effectively catalyzed the low-temperature FTS, displaying a high CO conversion (about 90%) and good 05 hydrocarbon productivity (about 0.22 a.,/,(cat) -h)' This demonstrates the feasibility of using the iron-ore-based catalysts as inexpensive and disposable catalysts for the low-temperature FTS,</P>

A new synthesis of carbon encapsulated Fe5C2 nanoparticles for high-temperature Fischer-Tropsch synthesis.

Hong, Seok Yong,Chun, Dong Hyun,Yang, Jung-Il,Jung, Heon,Lee, Ho-Tae,Hong, Sungjun,Jang, Sanha,Lim, Jung Tae,Kim, Chul Sung,Park, Ji Chan RSC Pub 2015 Nanoscale Vol.7 No.40

<P>Using a simple thermal treatment under a CO flow, uniform micrometer-sized iron oxalate dihydrate cubes prepared by hydrothermal reaction were transformed into Fe5C2@C nanoparticles to form a mesoporous framework; the final structure was successfully applied to the high-temperature Fischer-Tropsch reaction and it showed high activity (CO conversion = 96%, FTY = 1.5 ?? 10(-4) molCO gFe(-1) s(-1)) and stability.</P>

A New Automatic Gait Cycle Partitioning Method and Its Application to Human Identification

Sungjun Hong,Euntai Kim 한국지능시스템학회 2017 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.17 No.2

Gait cycle partitioning is very important prior to human gait analysis such as gait modeling, gait recognition, gait feature analysis, etc. In this paper, we propose a new automatic gait cycle partitioning method based on two kinds of simple gait representation. Then, the propose method is applied to find keyframe corresponding the rest position for gait-based human identification system. To demonstrate the validity of the proposed method, the CASIA gait dataset A and the SOTON gait database are used to evaluate the recognition performance of the gait recognition system identifying subjects using the decision level fusion based on majority voting.

Scenario analysis for estimating the learning rate of photovoltaic power generation based on learning curve theory in South Korea

Hong, Sungjun,Chung, Yanghon,Woo, Chungwon Elsevier 2015 ENERGY Vol.79 No.-

<P><B>Abstract</B></P> <P>South Korea, as the 9th largest energy consuming in 2013 and the 7th largest greenhouse gas emitting country in 2011, established ‘Low Carbon Green Growth’ as the national vision in 2008, and is announcing various active energy policies that are set to gain the attention of the world. In this paper, we estimated the decrease of photovoltaic power generation cost in Korea based on the learning curve theory. Photovoltaic energy is one of the leading renewable energy sources, and countries all over the world are currently expanding R&D, demonstration and deployment of photovoltaic technology. In order to estimate the learning rate of photovoltaic energy in Korea, both conventional 1FLC (one-factor learning curve), which considers only the cumulative power generation, and 2FLC, which also considers R&D investment were applied. The 1FLC analysis showed that the cost of power generation decreased by 3.1% as the cumulative power generation doubled. The 2FCL analysis presented that the cost decreases by 2.33% every time the cumulative photovoltaic power generation is doubled and by 5.13% every time R&D investment is doubled. Moreover, the effect of R&D investment on photovoltaic technology took after around 3 years, and the depreciation rate of R&D investment was around 20%.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We analyze the learning effects of photovoltaic energy technology in Korea. </LI> <LI> In order to calculate the learning rate, we use 1FLC (one-factor learning curve) and 2FLC methods, respectively. </LI> <LI> 1FLC method considers only the cumulative power generation. </LI> <LI> 2FLC method considers both cumulative power generation and knowledge stock. </LI> <LI> We analyze a variety of scenarios by time lag and depreciation rate of R&D investment. </LI> </UL> </P>

Sensitivity Analysis of Width Representation for Gait Recognition

Hong, Sungjun,Kim, Euntai Korean Institute of Intelligent Systems 2016 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.16 No.2

In this paper, we discuss a gait representation based on the width of silhouette in terms of discriminative power and robustness against the noise in silhouette image for gait recognition. Its sensitivity to the noise in silhouette image are rigorously analyzed using probabilistic noisy silhouette model. In addition, we develop a gait recognition system using width representation and identify subjects using the decision level fusion based on majority voting. Experiments on CASIA gait dataset A and the SOTON gait database demonstrate the recognition performance with respect to the noise level added to the silhouette image.