• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38C no.8
• /
• pp.706-712
• /
• 2013

In this paper, channel modeling of VLC(Visible Light Communication) was investigated under indirect lightning circumstance which was the way that all phontons started from LED(Light Emitting Diode) were reached on the floor with NLOS paths. I supposed width(6m), depth(4m), height(2.2m) cube room circumstance for VLC communication channel and supposed that 4 LEDs were located at 2m height, which emitted photons at the direction of wall and ceiling. Channel characteristics, which were power attenuation and delayed receiving of light signal, were abstracted from receivers(PDs) which were located at 0.5m above from floor. The availability of channel was verified via BPSK based communication simulation.

• Natural Product Sciences
• /
• v.22 no.4
• /
• pp.293-298
• /
• 2016

Plant-derived triterpenoids commonly possesses biological properties such as anti-inflammatory, antimicrobial, anti-viral and anti-cancer. Luvunga scandens is one of the plant that produced triterpenoids. The aims of the study was to analyze cell cycle profile and to determine the expression of p53 unregulated modulator of apoptosis (PUMA), caspase-8 and caspase-9 genes at mRNA level in MCF-7 cell line treated with two triterpenoids, flindissol (1) and 3-oxotirucalla-7,24-dien-21-oic-acid (2) isolated from L. scandens. The compounds were tested for cell cycle analysis using flow cytometer and mRNA expression level using quantitative RT-PCR. The number of MCF-7 cells population which distributed in Sub G1 phase after treated with compound 1 and 2 were 7.7 and 9.3% respectively. The evaluation of the expression of genes showed that both compounds exhibited high level of expression of PUMA, caspase-8 and caspase-9 as normalized to ${\beta}-actin$ via activation of those genes. In summary, the isolated compounds of L. scandens plant showed promising anticancer properties in MCF-7 cell lines.

• The Korean Journal of Physiology and Pharmacology
• /
• v.21 no.1
• /
• pp.99-106
• /
• 2017

Obesity is a critical risk factor for the hypertension. Although angiotensin II (Ang II) in obese individuals is known to be upregulated in obesity-induced hypertension, direct evidence that explains the underlying mechanism for increased vascular tone and consequent increase in blood pressure (BP) is largely unknown. The purpose of this study is to investigate the novel mechanism underlying Ang II-induced hyper-contractility and hypertension in obese rats. Eight-week old male Sprague-Dawley rats were fed with 60% fat diet or normal diet for 4 months. Body weight, plasma lipid profile, plasma Ang II level, BP, Ang II-induced vascular contraction, and expression of regulatory proteins modulating vascular contraction with/without Ang II stimulation were measured. As a result, high fat diet (HFD) accelerated age-dependent body weight gaining along with increased plasma Ang II concentration. It also increased BP and Ang II-induced aortic contraction. Basal expression of p-CPI-17 and myosin light chain (MLC) kinase was increased by HFD along with increased phosphorylation of MLC. Ang II-induced phosphorylation of CPI-17 and MLC were also higher in HFD group than control group. In conclusion HFD-induced hypertension is through at least in part by increased vascular contractility via increased expression and activation of contractile proteins and subsequent MLC phosphorylation induced by increased Ang II.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.19 no.2
• /
• pp.69-74
• /
• 2020

In this study, we proposed a method for surface profiling aspheric lens molds using a precision displacement sensor with a spatial scanning mechanism. The precision displacement sensor is based on the confocal principle using a broadband light source, providing a 10 nm resolution over a 0.3 mm measurable range. The precision of the sensor, depending on surface slope, was evaluated via Allan deviation analysis. We then developed an automatic surface profiling system by measuring the cross-sectional profile of a lens mold. The precision of the sensor at the flat surface was 10 nm at 10 ms averaging time, while 200 ms averaging time was needed for identical precision at the steepest slope at 25 deg. When we compared the measurement result of the lens mold to a commercial surface profiler, we found that the accuracy of the developed system was less than 90 nm (in terms of 3 sigmas of error) between the two results.

• Advances in Computational Design
• /
• v.5 no.4
• /
• pp.397-416
• /
• 2020

Functionally graded material (FGM) illustrates a novel class of composites that consists of a graded pattern of material composition. FGM is engineered to have a continuously varying spatial composition profile. Current work focused on buckling analysis of beam made of stepwise linear and quadratic graded material in axial direction subjected to axial span-load with piecewise function and rested on shear layer based on classical beam theory. The various boundary and natural conditions including simply supported (S-S), pinned - clamped (P-C), axial hinge - pinned (AH-P), axial hinge - clamped (AH-C), pinned - shear hinge (P-SHH), pinned - shear force released (P-SHR), axial hinge - shear force released (AH-SHR) and axial hinge - shear hinge (AH-SHH) are considered. To the best of the author's knowledge, buckling behavior of this kind of Euler-Bernoulli beams has not been studied yet. The equilibrium differential equation is derived by minimizing total potential energy via variational calculus and solved analytically. The boundary conditions, natural conditions and deformation continuity at concentrated load insertion point are expressed in matrix form and nontrivial solution is employed to calculate first buckling loads and corresponding mode shapes. By increasing truncation order, the relative error reduction and convergence of solution are observed. Fast convergence and good compatibility with various conditions are advantages of the proposed method. A MATLAB code is provided in appendix to employ the numerical procedure based on proposed method.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2003.11a
• /
• pp.193-197
• /
• 2003

Radar target identification can be achieved by using various radar signatures, such as one-dimensional(1-D) range profile, 2-D radar images, and 1-D or 2-D scattering centers on a target. In this letter, five 1-D scattering center extraction methods are discussed - TLS(Total Least Square)-Prony, Fast Root-MUSIC (Multiple Signal Classification), Matrix-Pencil, GEESE(GEneralized Eigenvalues utilizing Signal-subspace Eigenvalues), TLS-ESPRIT(Total Least Squares - Estimation of Signal Parameters via Rotational Invariance Technique), These methods are compared in the context of estimation accuracy as well as a computational efficiency using a noisy data. Finally these methods are applied to the target classification experiment with the measured data in the POSTECH compact range facility.

• Journal of the Korean Home Economics Association
• /
• v.48 no.8
• /
• pp.113-128
• /
• 2010

The purposes of this study were 1) to divide consumers into segments according to their consumption attitude and subjective knowledge about natural dyed products 2) to develop a profile for each segment with respect to the media types, the preferred media programs, the information sources, the lifestyle activities and the demographics. Data(n = 213) was collected using questionnaires via the internet. By cluster analysis of the consumers' attitude and their subjective knowledge about natural dyed products, four groups were identified 1) the loyal consumption group (20.1%), 2) the conditional/reluctant consumption group(36.6%), 3) the negative/reluctant consumption group(24.2%) and 4) the non purchasers(19.1%). Several characteristics of these four groups were then compared by ANOVA and chi-square statistics. The results indicated that the consumption attitude and subjective knowledge could be the criteria for segmenting the consumers and that the segmented groups had unique consumer characteristics. Implications of this study were discussed.

• Archives of Plastic Surgery
• /
• v.39 no.4
• /
• pp.284-290
• /
• 2012

Open reduction and anatomic reduction can create better function for the temporomandibular joint, compared with closed treatment in mandible fracture surgery. Therefore, the double miniplate fixation technique via mini-retromandibular incision was used in order to make the most stable fixation when performing subcondylar fracture surgery. Those approaches provide good visualization of the subcondyle from the posterior edge of the ramus, allow the surgeon to work perpendicularly to the fracture, and enable direct fracture management. Understanding the biomechanical load in the fixation of subcondylar fractures is also necessary in order to optimize fixation methods. Therefore, we measured the biomechanical loads of four different plate fixation techniques in the experimental model regarding mandibular subcondylar fractures. It was found that the loads measured in the two-plate fixation group with one dynamic compression plate (DCP) and one adaption plate showed the highest deformation and failure loads among the four fixation groups. The loads measured in the one DCP plate fixation group showed higher deformation and failure loads than the loads measured in the two adaption plate fixation group. Therefore, we conclude that the selection of the high profile plate (DCP) is also important in order to create a stable load in the subcondylar fracture.

• Wind and Structures
• /
• v.31 no.3
• /
• pp.185-196
• /
• 2020

A method to reduce the wind pressure at the leading edge of a noise barrier was investigated by gradually lowering the height of a member added to the end of the noise barrier. The shape of the lowered height of the added member was defined by its length and slope, and the optimal variable was determined in wind tunnel testing via the boundary-layer wind profile. The goal of the optimal shape was to reduce the wind pressure at the leading edge of the noise barrier to the level suggested in the Eurocode and to maintain the base-bending moment of the added member at the same level as the noise-barrier section. Using parametric wind tunnel investigation, an added member with a slope of 1:2 that protruded 1.2 times the height of the noise barrier was proposed. This added member is expected to simplify, or at least minimize, the types of column members required to equidistantly support both added members and noise barriers, which should thereby improve the safety and construction convenience of noise-barrier structures.

• Economic and Environmental Geology
• /
• v.32 no.1
• /
• pp.101-111
• /
• 1999

Sedimentary organic matter, exposed to continental surficial environment, reacts with oxygen supplied from the atmosphee and forms carbon-containing oxidation products. Knowledge of the rate and mechanisms of sedimentary organic matter weathering is important because it is one of the major controls on atmospheric oxygen level through geologic time. Under the abiological conditions, the oxidation rate of coal organic matter by molecular oxygen is enhanced by the increase of oxygen concentration and temperature. At ambient temperature and pressure, aqueous coal oxidation results in the formation of dissolved $CO_2$ dissolved organic carbon and solid oxidation products which are all quantitatively significant reaction products. The effects of pH, ultraviolet light, and microbial activity on the weathering of sedimentary organic matter are poorly contrained. Based on the results of geochmical and environmental studies, it is believed that the photochemical reaction should play an important role in the decomposition and oxidation of sedimentary organic matter removed from the weathering profile. At higher pH conditions, the production rate of DOC can be accelerated due to base catalysis. These high molecular weight oranic matter can react with man-made pollutants such as heavy metal ions via adsorption/desorption or ion exchange reactions. The effect of microbial activity on the oxidative weathering of sedimentary organic matter is poorly understood and remains to be studied.