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Assessment of the effect on the human body of the flicker of OLED displays of smartphones
Kim Minhyuk 한국정보디스플레이학회 2021 Journal of information display Vol.22 No.4
This paper considers the effects on the human body of the flicker of organic light-emitting diode (OLED) displays. Related studies have been conducted due to reports of cases of adverse health effects of the use of artificial lighting. Interest in this problem recently intensified with the development of various new displays and the longer exposure time of people to them. Therefore, the previous studies on the effects of artificial lighting on the human body are described in this paper, and based on them, the dimming technique for liquid-crystal displays and OLED displays of smartphones is explained and the effect of the flicker of OLED displays on the human body is assessed.
Minhyuk Kim,Joo Young Lee 건강기능식품미래포럼 2023 건강기능식품미래포럼 학술지 Vol.3 No.1
Sulforaphane (SFN) is a type of phytochemical found in cruciferous vegetables like broccoli. It belongs to the group of organosulfur compounds and is produced from glucoraphanin through the action of myrosinase when these vegetables are consumed. SFN is known for its anti-inflammatory and antioxidant properties, which may have a positive effect on human health and disease. Type 2 diabetes, a chronic metabolic condition characterized by high blood sugar levels, is becoming increasingly common in modern societies worldwide. This disease can lead to complications that affect the functions of important organs like heart, kidneys, and eyes. In this review, we discuss the mechanisms by which SFN acts at the cellular and molecular levels and discuss its potential role in preventing the complications of type 2 diabetes.
Numerical Method for Exposure Assessment of Wireless Power Transmission under Low-Frequency Band
Minhyuk Kim,SangWook Park,Hyun-Kyo Jung 한국자기학회 2016 Journal of Magnetics Vol.21 No.3
In this paper, an effective numerical analysis method is proposed for calculating dosimetry of the wireless power transfer system operating low-frequency ranges. The finite-difference time-domain (FDTD) method is widely used to analyze bio-electromagnetic field problems, which require high resolution, such as a heterogeneous whole-body voxel human model. However, applying the standard method in the low-frequency band incurs an inordinate number of time steps. We overcome this problem by proposing a modified finite-difference time-domain method which utilizes a quasi-static approximation with the surface equivalence theorem. The analysis results of the simple model by using proposed method are in good agreement with those from a commercial electromagnetic simulator. A simulation of the induced electric fields in a human head voxel model exposed to a wireless power transmission system provides a realistic example of an application of the proposed method. The simulation results of the realistic human model with the proposed method are verified by comparing it with the conventional FDTD method.
MinHyuk Kim,JoungSook Ahn,Seongho Min 대한신경정신의학회 2015 PSYCHIATRY INVESTIGATION Vol.12 No.4
Objective-To examine the reliability and validity of the self-report Korean version of Strengths and Difficulties Questionnaire (SDQ-Kr) in the community sample. Methods-The SDQ-Kr was administered to a large sample of school children and adolescents (n=2814) and youth attendees of a psychiatric clinic (n=385) aged 11–16 years. To examine temporal stability, the same questionnaire was administered to a subsample of 167 school youths five to six weeks after the initial assessment. To examine the reliability, we calculated Cronbach’s alpha coefficients for internal consistency and Pearson’s correlations for test-retest stability. In order to evaluate the factorial structure of the SDQ-Kr items, we conducted an exploratory factor analysis (EFA) with varimax rotation. Finally, discriminant validity was examined by using receiver operating characteristic (ROC) curves employing the area under the curve (AUC) as an index of discriminant ability. Results-Although the internal consistency of some subscales of the SDQ-Kr was somewhat less satisfactory (alpha coefficients; 0.28–0.54) than the English original, coefficients for the total difficulties scores approached sufficient levels (coefficients; 0.69). Other psychometric properties including discriminant validity (AUC for total difficulties and four subscales >0.7) were comparable to those obtained in other language studies. Conclusion-The self-report SDQ-Kr exhibited a low level of reliability, indicating that some items need to be further evaluated and revised to improve the psychometric properties. We suggest that the total difficulties score could be used with more confidence for screening possible mental health problems in youths.
Kim, Sungjun,Kim, Junhyung,Gajendiran, Mani,Yoon, Minhyuk,Hwang, Mintai P.,Wang, Yadong,Kang, Byung-Jae,Kim, Kyobum American Chemical Society 2018 Biomacromolecules Vol.19 No.11
<P>Direct administration of bone morphogenetic protein-2 (BMP-2) for bone regeneration could cause various clinical side effects such as osteoclast activation, inflammation, adipogenesis, and bone cyst formation. In this study, thiolated gelatin/poly(ethylene glycol) diacrylate (PEGDA) interpenetrating (IPN) composite hydrogels were developed for guided skull bone regeneration. To promote bone regeneration, either polycation-based coacervates (Coa) or gelatin microparticles (GMPs) were incorporated within IPN gels as BMP-2 carriers. Both BMP-2 loaded Coa and BMP-2 loaded GMPs showed significantly enhanced <I>in vitro</I> alkaline phosphate (ALP) activity of human mesenchymal stem cells (hMSCs) than non-BMP-2 treated control. Moreover, BMP-2 loaded GMPs group exhibited statistically increased ALP activity compared to both bolus BMP-2 administration and BMP-2 loaded Coa group, indicating that our carriers could protect and maintain biological activity of cargo BMP-2. Sustained release kinetics of BMP-2 from IPN composite hydrogels could be controlled by different formulations. For <I>in vivo</I> bone regeneration, various IPN gel formulations (i.e., (1) control, (2) only hydrogel, (3) hydrogel with bolus BMP-2, (4) hydrogel with BMP-2-loaded Coa, and (5) hydrogel with BMP-2-loaded GMPs) were bilaterally implanted into 5 mm-sized rat calvarial defects. After 4 weeks, micro-CT and histological analysis were performed to evaluate new bone formation. Significantly higher scores for bony bridging and union were observed in BMP-2-loaded Coa and BMP-2-loaded GMP groups as compared to other formulations. In addition, rats treated with BMP-2-loaded GMPs showed a significantly higher ratio of bone volume/total volume and lower trabecular separation scores than others. Finally, rats treated with either Coa or GMP groups exhibited a significant increase in bone formation area, as assessed via histomorphometric analysis. Taken together, it could be concluded that Coa and GMPs were effective carriers to maintain the bioactivity of cargo BMP-2 during its sustained release. Consequently, our IPN composite hydrogel system that combines such BMP-2 carriers could effectively promote skull bone regeneration.</P> [FIG OMISSION]</BR>
An Efficient Design Methodology of Serial Concatenate Coding Scheme for CATV Transmission System
Minhyuk Kim,Jongtae Bae,Suksoon Choi,Taedoo Park,Namsoo Kim,Jiwon Jung 대한전자공학회 2008 ITC-CSCC :International Technical Conference on Ci Vol.2008 No.7
This paper describes the design methodology of serial concatenate of extended RS code, trellis coded modulation with 64-/256-QAM, based upon testing and characterization of cable systems. In implementing the cable modem, there are some problems to fabricate and fitting on FPGA chip. First, many clocks are needed in implementing cable modem because of different code rate and different modulation types. To reduce the number of clocks, we use the two memories, which are different clock speed for reading and writing data. Second, this system lost the bit-synchronization and framesynchronization in decoder, the system recognizes that all data is error. This paper solves the problems by using simple 5-stage registers and unique sync-word. Based on solutions for about problems, the cable modem is fabricated on FPGA chip name as Vertex Ⅱ pro xc2vp30-5 by Xilinx, and we confirmed the effectiveness of the results.