Flickering Effect Reduction Based on the Modified Transformation Function for Video Contrast Enhancement

Yang, Hyeonseok,Park, Jinwook,Moon, Youngshik The Institute of Electronics and Information Engin 2014 IEIE Transactions on Smart Processing & Computing Vol.3 No.6

This paper proposes a method that reduces the flickering effect caused by A-GLG (Adaptive Gray-Level Grouping) during video contrast enhancement. Of the GLG series, A-GLG shows the best contrast enhancement performance. The GLG series is based on histogram grouping. Histogram grouping is calculated differently between the continuous frames with a similar histogram and causes a subtle change in the transformation function. This is the reason for flickering effect when the video contrast is enhanced by A-GLG. To reduce the flickering effect caused by A-GLG, the proposed method calculates a modified transformation function. The modified transformation function is calculated using a previous and current transformation function applied with a weight separately. The proposed method was compared with A-GLG for flickering effect reduction and video contrast enhancement. Through the experimental results, the proposed method showed not only a reduced flickering effect, but also video contrast enhancement.

Laser based impedance measurement for pipe corrosion and bolt-loosening detection

Yang, Jinyeol,Liu, Peipei,Yang, Suyoung,Lee, Hyeonseok,Sohn, Hoon Techno-Press 2015 Smart Structures and Systems, An International Jou Vol.15 No.1

This study proposes a laser based impedance measurement system and impedance based pipe corrosion and bolt-loosening monitoring techniques under temperature variations. For impedance measurement, the laser based impedance measurement system is optimized and adopted in this paper. First, a modulated laser beam is radiated to a photodiode, converting the laser beam into an electric signal. Then, the electric signal is applied to a MFC transducer attached on a target structure for ultrasonic excitation. The corresponding impedance signals are measured, re-converted into a laser beam, and radiated back to the other photodiode located in a data interrogator. The transmitted impedance signals are treated with an outlier analysis using generalized extreme value (GEV) statistics to reliably signal off structural damage. Validation of the proposed technique is carried out to detect corrosion and bolt-loosening in lab-scale carbon steel elbow pipes under varying temperatures. It has been demonstrated that the proposed technique has a potential to be used for structural health monitoring (SHM) of pipe structures.

Development of a fiber-guided laser ultrasonic system resilient to high temperature and gamma radiation for nuclear power plant pipe monitoring

Yang, Jinyeol,Lee, Hyeonseok,Lim, Hyung Jin,Kim, Nakhyeon,Yeo, Hwasoo,Sohn, Hoon IOP Pub 2013 Measurement Science and Technology Vol.24 No.8

<P>This study develops an embeddable optical fiber-guided laser ultrasonic system for structural health monitoring (SHM) of pipelines exposed to high temperature and gamma radiation inside nuclear power plants (NPPs). Recently, noncontact laser ultrasonics is gaining popularity among the SHM community because of its advantageous characteristics such as (a) scanning capability, (b) immunity against electromagnetic interference (EMI) and (c) applicability to high-temperature surfaces. However, its application to NPP pipelines has been hampered because pipes inside NPPs are often covered by insulators and/or target surfaces are not easily accessible. To overcome this problem, this study designs embeddable optical fibers and fixtures so that laser beams used for ultrasonic inspection can be transmitted between the laser sources and the target pipe. For guided-wave generation, an Nd:Yag pulsed laser coupled with an optical fiber is used. A high-power pulsed laser beam is guided through the optical fiber onto a target structure. Based on the principle of laser interferometry, the corresponding response is measured using a different type of laser beam guided by another optical fiber. All devices are especially designed to sustain high temperature and gamma radiation. The robustness/resilience of the proposed measurement system installed on a stainless steel pipe specimen has been experimentally verified by exposing the specimen to high temperature of up to 350 °C and optical fibers to gamma radiation of up to 125 kGy (20 kGy h<SUP>−1</SUP>).</P>

Efficient Process Network Implementation of Ray-Tracing Application on Heterogeneous Multi-Core Systems

Hyeonseok Jung,Hoeseok Yang 대한전자공학회 2016 IEIE Transactions on Smart Processing & Computing Vol.5 No.4

As more mobile devices are equipped with multi-core CPUs and are required to execute many compute-intensive multimedia applications, it is important to optimize the systems, considering the underlying parallel hardware architecture. In this paper, we implement and optimize ray-tracing application tailored to a given mobile computing platform with multiple heterogeneous processing elements. In this paper, a lightweight ray-tracing application is specified and implemented in Kahn process network (KPN) model-of-computation, which is known to be suitable for the description of real-time applications. We take an open-source C/C++ implementation of ray-tracing and adapt it to KPN description in the Distributed Application Layer framework. Then, several possible configurations are evaluated in the target mobile computing platform (Exynos 5422), where eight heterogeneous ARM cores are integrated. We derive the optimal degree of parallelism and a suitable distribution of the replicated tasks tailored to the target architecture.

Temperature-dependent Differences in Heading Response at Different Growth Stages of Rice

Lee, HyeonSeok,Choi, MyoungGoo,Lee, YunHo,Hwang, WoonHa,Jeong, JaeHyeok,Yang, SeoYeong,Lim, YeonHwa,Lee, ChungGen,Choi, KyungJin The Korean Society of Crop Science 2019 한국작물학회지 Vol.64 No.3

There is an increasing frequency in the occurrence of abnormal weather phenomena such as sharp increases and decreases in temperature. Under these weather conditions, the heading time of rice changes unexpectedly, which poses problems in agriculture. Therefore, we investigated the effect of temperature on the heading response at different growth stages in rice. During the period from transplanting to heading, the plants were subjected to different temperature treatments, each for a 9-day period, to observe the heading response. For the heading date analysis, "heading date" was defined as the number of days from transplanting to the appearance of the first spikelet. We found that the influence of temperature increased in the order of rooting stage, followed by meiosis, early tillering, spikelet differentiation, and panicle initiation stage in all ecological types and cultivars. In particular, unlike the results reported previously, the effect of temperature on heading during the photo-sensitive period was very small. Meanwhile, the influence of temperature on vegetative growth response at different growth stages was not consistent with heading response. These results can be used as basic data for predicting the variation in heading date owing to temperature variation at each growth stage. In addition, we propose that the concept of day length should be included in determining the influence of temperature on the photo-sensitive period.

Cerebral Perfusion Changes after Acetyl-L-Carnitine Treatment in Early Alzheimer's Disease Using Single Photon Emission Computed Tomography

Jeong, Hyeonseok S.,Park, Jong-Sik,Yang, YoungSoon,Na, Seung-Hee,Chung, Yong-An,Song, In-Uk Korean Dementia Association 2017 Dementia and Neurocognitive Disorders Vol.16 No.1

<P><B>Background and Purpose</B></P><P>Although acetyl-L-carnitine (ALC) treatment may have beneficial effects on Alzheimer's disease (AD), its underlying neural correlates remain unclear. The purpose of this study was to investigate cerebral perfusion changes after ALC treatment in AD patients using technetium-<SUP>99</SUP>m hexamethylpropylene amine oxime single photon emission computed tomography (SPECT).</P><P><B>Methods</B></P><P>A total of 18 patients with early AD were prospectively recruited and treated with ALC at 1.5 g/day for 1.4±0.3 years. At baseline and follow-up, brain SPECT, Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR), Global Deterioration Scale (GDS), and Neuropsychiatric Inventory (NPI) were used to assess participants. After ALC administration, changes in brain perfusion, severity of dementia, cognitive performance, and neuropsychiatric disturbances were examined.</P><P><B>Results</B></P><P>After ALC administration, changes in scores of MMSE, CDR, GDS, and NPI were not statistically significant (<I>p</I>>0.05). Voxel-wise whole-brain image analysis revealed that perfusion was significantly (<I>p</I><0.001) increased in the right precuneus whereas perfusion was reduced in the left inferior temporal gyrus (<I>p</I><0.001), the right middle frontal gyrus (<I>p</I><0.001), and the right insular cortex (<I>p</I>=0.001) at follow-up.</P><P><B>Conclusions</B></P><P>Although previous studies have suggested that AD patients generally demonstrate progressive deterioration in brain perfusion and clinical symptoms, this study reveals that the perfusion of the precuneus is increased in AD patients after ALC administration and their cognitive and neuropsychiatric symptoms are not aggravated. Further studies are warranted to determine the potential association between perfusion increase in the precuneus and clinical symptoms after ALC treatment in AD patients.</P>

벼 오존가스 노출에 따른 초기 생육 및 안토시아닌 생합성 변화 분석 연구

이현석 ( Hyeonseok Lee ),황운하 ( Woonha Hwang ),양서영 ( Seoyeong Yang ),송영서 ( Yeongseo Song ),임우진 ( Woojin Im ),정회정 ( Hoejeong Jeong ),이충근 ( Chunggen Lee ),김주희 ( Juhee Kim ),최명구 ( Myounggoo Choi ) 한국농림기상학회 2023 한국농림기상학회지 Vol.25 No.2

Recently, the concentration of fine dustcausative substances (NOx, VOC, etc.) in the atmosphere has increased, resulting in high concentrations of tropospheric ozone (O3) and increased damage to crops. This study aimed to analyze the impact of high concentrations of ozone gas on the initial growth of rice plants and investigate the relationship between ozone damage resistance and anthocyanin biosynthesis. To achieve this, rice plants were exposed to elevated levels of ozone gas using an ozone chamber, and subsequent measurements were taken to assess changes in growth, the percentage of damaged leaves, and the anthocyanin content. The results revealed that varieties with a higher proportion of damaged leaves exhibited a relative increase in anthocyanin biosynthesis following ozone exposure. Notably, detrimental effects on growth, such as decreased biomass, were mitigated. Additionally, Anthocyanin biosynthesis genes in rice were listed by selecting homologous genes from Arabidopsis and Maize. The expression of OsF3H2, OsFLS1 and OsLDOX3 was induced during ozone treatment. This result is expected to contribute to the study of the protection mechanism of plants from ozone damage.

습식산화반응열을 고려한 GPV 내 열적 특성 해석

서현석(Hyeonseok Seo),이홍철(Hongcheol Lee),양준승(Junseung Yang),안재환(Jaehwan Ahn),황인주(Inju Hwang) 대한설비공학회 2009 대한설비공학회 학술발표대회논문집 Vol.2009 No.-

Gravity pressure vessels find their use in the wet oxidation of sewage sludge, which can be defined as the oxidation of organic and inorganic substances in an aqueous solution or suspension by means of oxygen or air at elevated pressures and temperatures. Numerical analyses were carried out for investigating the flow characteristics and wet air oxidation in the reaction vessel with various conditions such as supply oxidation and the supply positions of oxidation, etc. Wet air oxidation is promoted in the vicinity of bottom in the reactor with increase of oxygen supply. Also, it is the best condition to the oxidation supply position of 150 m and oxidation flow of 0.06 ㎏/s in the GPV reactor as the remnant of sludge and creation of organic acids.

Induction of autophagy by dimethyl cardamonin is associated with proliferative arrest in human colorectal carcinoma HCT116 and LOVO cells

Ko, Hyeonseok,Kim, Young‐,Joo,Amor, Evangeline C.,Lee, Jong Wha,Kim, Han‐,Cheon,Kim, Hee Ju,Yang, Hyun Ok Wiley Subscription Services, Inc., A Wiley Company 2011 Journal of cellular biochemistry Vol.112 No.9

<P><B>Abstract</B></P><P>Dimethyl cardamonin (2′,4′‐dihydroxy‐6′‐methoxy‐3′,5′‐dimethylchalcone; DMC) is a naturally occurring chalcone, and it is the major compound isolated from the leaves of <I>Syzygium samarangense</I> (Blume) Merr. & L.M. Perry (Myrtaceae). Experiments were conducted to determine the effects of DMC on cell proliferation, cell‐cycle distribution, and programmed cell death in cultures of human colorectal carcinoma HCT116 and LOVO cells. Results showed that DMC inhibited HCT116 and LOVO cell proliferation and induced G<SUB>2</SUB>/M cell cycle arrest, which was associated with the conversion of microtubule associated protein light chain 3 (LC3)‐I–LC3‐II, an autophagosome marker, and the incorporation of monodansylcadaverine (MDC), a marker for the acidic compartment of autolysosomes or acidic vesicular organelles. The treatment of HCT116 and LOVO cells using a combination of DMC with an autophagy inhibitor, such as 3‐methyladenine (3‐MA), beclin 1 siRNA, or atg5 siRNA, suppressed the effect of DMC‐mediated anti‐proliferation. These results imply that DMC can suppress colorectal carcinoma HCT116 and LOVO cell proliferation through a G<SUB>2</SUB>/M phase cell‐cycle delay, and can induce autophagy, the hallmark of Type II programmed cell death (PCD). Taken together, our results suggest that DMC may be an effective chemotherapeutic agent for HCT116 and LOVO colorectal carcinoma cells. J. Cell. Biochem. 112: 2471–2479, 2011. © 2011 Wiley‐Liss, Inc.</P>

Autophagy Inhibition Enhances Apoptosis Induced by Ginsenoside Rk1 in Hepatocellular Carcinoma Cells

KO, Hyeonseok,KIM, Young-Joo,PARK, Jin-Soo,PARK, Jeong Hill,YANG, Hyun Ok Japan Society for Bioscience, Biotechnology, and A 2009 Bioscience, Biotechnology, and Biochemistry Vol.73 No.10

<P>Our previous study indicated that ginsenoside Rk1 has anti-tumor activity and that its mode of action in HepG2 cells treated for 48 h involves coordinated inhibition of telomerase and induction of apoptosis. In the present study, we found that Rk1 induces both G<SUB>1</SUB> phase arrest and autophagy, but not apoptosis, at an earlier stage of treatment. A 24-h incubation of HepG2cells with Rk1 induced G<SUB>1</SUB> phase arrest. Rk1-induced autophagy was documented by the conversion of microtubule associated protein light chain 3 (LC3)-I to LC3-II, an autophagosome marker, and monodansylcadaverine (MDC) incorporation into autolysosomes. Combination of Rk1 with an autophagy inhibitor, such as bafilomycin A1 or beclin 1 siRNA, enhanced the anti-tumor effect of Rk1. These results imply that autophagy functions as a survival mechanism in HepG2 cells against Rk1-induced apoptosis. Taken together, our results support the use of autophagy inhibitors in combination with Rk1 as an effective anti-cancer regimen in HepG2 cells.</P>