• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.194-198
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• 2021

LoRa is a physical layer technology that is designed to provide a reliable long-range communication with introducing CSS and with introducing a loco parentis tree network. Since a leaf can utilize multiple parents at the same time with a single transmission, PDR increases logarithmically as the number of gateways increases. Because of the ALOHA-like MAC of LoRa, however, the PDR degrades even under the loco parentis tree topology similarly to the single-gateway environment. Our proposed method is aimed to achieve SDMA approach to reuse the same frequency in different areas. For that purpose, it elaborately controls each TxPower of the senders for each message in concurrent transmission to survive the collision at each different gateway. The gain from this so-called capture effect increases the capacity of resource-hungry LPWAN. Compared to a typical collision-free controlled-access scheme, our method outperforms by 10-35% from the perspective of the total count of the consumed time slots. Also, due to the power control mechanism in our method, the energy consumption reduced by 20-40%.

• Imaging Science in Dentistry
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• v.35 no.4
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• pp.191-198
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• 2005

Purpose: To characterize the effects of 2-deoxy-D-glucose (2DG) and quercetin (QCT) on cytokine secretion of IL-6, $TGF-\beta$ and gene expression of Col I in irradiated MC3T3-E1 cells Materials and Methods: The MC3T3-El cells were cultured in an a-MEM supplemented with 5mM 2DG or 10mM QCT and then the cells were incubated 12h before irradiation with 2, 4, 6, and 8Gy X-ray using a linear accelerator delivered at a dose rate of 1.5Gy/min. Level of IL-6 and $TGF-\beta$ was determined by ELISA. Also expression of Col I was examined by RT-PCR. Results: In accordance with the radiation dose, the amount of $TGF-\beta$ was not different in RA + QCT, but it showed a peak value in control and RA + 2DG at 4Gy on the 3rd day. However, all groups showed a decreasing tendency dose-dependently in RA+QCT on the 7th day (p<0.01). In accordance with the radiation dose, the amount of IL-6 increased dose-dependently in all groups on the 3rd day. On the 7th and 21st day, all groups showed peak values at 4Gy. RA+QCT showed a slightly increased amount of IL-6 at 2Gy, but it showed a slightly decreased amount at 4, 6, and 8Gy. In accordance with the period of culture after irradiation, the expression of Col I increased dose-dependently in RA+QCT. Conclusion: The result showed that QCT acted as radiosensitizer in the secretion of $TGF-\beta$ and gene expression of Col I during differentiation in irradiated MC3T3-E1 cells at the cellular level.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.4
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• pp.175-182
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• 1998

Recently it is reported that anomalously low saline surface waters (salinity < 32) occurred at the Ulleung Basin in the East Sea-Japan Sea, during early September to November 1996. Apparent source of such a low saline watermass seems remotely linked to the Changjiang Dilute Water (CDW), which expands to the vicinity of Cheju Island during a flood season. Based on the assumption that waters passing through the Western Channel of the Korea Strait are formed by a mixing of Kuroshio Water and CDW, simplified two end-member mixing model using $^{228}Ra/^{226}Ra$ as a conservative tracer is applied to calculate the contribution of each end member for the formation of low saline surface seawater. Model calculations show CDW contributes $58{\pm}3%$ in September 1996 (S=32.17) and $10{\pm}3%$ in February 1997 (S=34.53) in the formation of surface water flowing into the Western Channel of the Korea Strait. Although results arc deduced from a simplified model with limited data, this study demonstrates that Changjiang discharge is clearly traceable to the interior of the East Sea-Japan Sea in fall season. Undergoing Three Valley Dam construction in the Changjiang River would invoke inevitable changes in the nature and discharge of CDW and its impacts on the marine environment might be significant in the northern East China Sea and even in the Ulleng Basin for coming decades.

• Tuberculosis and Respiratory Diseases
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• v.82 no.1
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• pp.42-52
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• 2019

Background: Transforming growth factor ${\beta}$ (TGF-${\beta}$), retinoic acid (RA), p38 mitogen-activated protein kinase (MAPK), and MEK signaling play critical roles in cell differentiation, proliferation, and apoptosis. We investigated the effect of RA and the role of these signaling molecules on the phosphorylation of Smad2/3 (p-Smad2/3) induced by TGF-${\beta}1$. Methods: A549 epithelial cells and CCD-11Lu fibroblasts were incubated and stimulated with or without all-trans RA (ATRA) and TGF-${\beta}1$ and with MAPK or MEK inhibitors. The levels of p-Smad2/3 were analyzed by western blotting. For animal models, we studied three experimental mouse groups: control, bleomycin, and bleomycin+ATRA group. Changes in histopathology, lung injury score, and levels of TGF-${\beta}1$ and Smad3 were evaluated at 1 and 3 weeks. Results: When A549 cells were pre-stimulated with TGF-${\beta}1$ prior to RA treatment, RA completely inhibited the p-Smad2/3. However, when A549 cells were pre-treated with RA prior to TGF-${\beta}1$ stimulation, RA did not completely suppress the p-Smad2/3. When A549 cells were pre-treated with MAPK inhibitor, TGF-${\beta}1$ failed to phosphorylate Smad2/3. In fibroblasts, p38 MAPK inhibitor suppressed TGF-${\beta}1$-induced p-Smad2. In a bleomycin-induced lung injury mouse model, RA decreased the expression of TGF-${\beta}1$ and Smad3 at 1 and 3 weeks. Conclusion: RA had inhibitory effects on the phosphorylation of Smad induced by TGF-${\beta}1$ in vitro, and RA also decreased the expression of TGF-${\beta}1$ at 1 and 3 weeks in vivo. Furthermore, pre-treatment with a MAPK inhibitor showed a preventative effect on TGF-${\beta}1$/Smad phosphorylation in epithelial cells. As a result, a combination of RA and MAPK inhibitors may suppress the TGF-${\beta}1$-induced lung injury and fibrosis.

• The Journal of Information Systems
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• v.29 no.2
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• pp.131-147
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• 2020

Purpose The purpose of this study is to develop intelligent vehicle parking distribution system based on LoRa network at the circumstance of traffic congestion during cultural festival in a local city. This paper proposes a parking dispatch and distribution system using a Q-learning algorithm to rapidly disperse traffics that increases suddenly because of in-bound traffics from the outside of a city in the real-time base as well as to increase parking probability in a parking lot which is widely located in a city. Design/methodology/approach The system get information on realtime-base from the sensor network of IoT (LoRa network). It will contribute to solve the sudden increase in traffic and parking bottlenecks during local cultural festival. We applied the simulation system with Queuing model to the Yudeung Festival in Jinju, Korea. We proposed a Q-learning algorithm that could change the learning policy by setting the acceptability value of each parking lot as a threshold from the Jinju highway IC (Interchange) to the 7 parking lots. LoRa Network platform supports to browse parking resource information to each vehicle in realtime. The system updates Q-table periodically using Q-learning algorithm as soon as get information from parking lots. The Queuing Theory with Poisson arrival distribution is used to get probability distribution function. The Dijkstra algorithm is used to find the shortest distance. Findings This paper suggest a simulation test to verify the efficiency of Q-learning algorithm at the circumstance of high traffic jam in a city during local festival. As a result of the simulation, the proposed algorithm performed well even when each parking lot was somewhat saturated. When an intelligent learning system such as an O-learning algorithm is applied, it is possible to more effectively distribute the vehicle to a lot with a high parking probability when the vehicle inflow from the outside rapidly increases at a specific time, such as a local city cultural festival.

• The Korean Journal of Rehabilitation Nursing
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• v.2 no.2
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• pp.193-205
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• 1999

This study was carried out to identify the important risk factors for reduced bone mass of postmenopausal RA patients and to develop discriminant function which can classify postmenopausal RA patients with either reduced or normal bone mass. Through the literature review, individual characteristics such as age, body weight, height, age of menarche, duration of menopause, gravity, parity, and breast feeding period and factors of life style such as milk consumption exercise habit, alcohol intake, cigarette smoking, coffee consumpt ion , disease activity, corticosteroid therapy were identified as influencing factors of reduced bone mass in RA patients Sixty eight postmenopausal women with rheumatoid arthritis aged between 42 and 76 were selected among those who checked bone mineral density in lumbar spine and femur from october, 1998 to Apr il, 1999 at Dong-a university hospital in Pusan. Assessment of disease activity, duration of disease and corticosteroid therapy were made by the same rheumatologist and included Ritchie articular index, erythrocyte sedimentation rate, and C-reactive protein on measuring bone mineral density. Cumulative steroid dosage was calculated from the daily dosage multiplied by t h e number of days received. The information of other risk factor including health assessment score, individual characteristics and life style factors were collected by questionnaire. Bone mineral density(BMD) was measured using DXA at lumbar spine and femoral Ward's triangle. Discriminant function(regression equation) was developed for estimating the likelihood of the presence or absence of reduced bone mass. The results are as follows: Among the subjects, thirteen(19.1%) exhibited osteoporosis in lumbar spine and twenty four(35.3%) exhibited osteoporosis in femoral Ward's triangle. For lumbar spine, the variables significant were age, body weight, health assessment score, while for femoral Ward's triangle, age, body weight, duration of disease. But disease activity and corticosteroid therapy were not signigicant to distinguish reduced bone mass from normal bone mass. When the discriminant function was evaluated by comparing the observed out come with predicted out come, the discriminant function correctly classified 85.4% of patients with reduce bone mass and 63.0% of patients with normal bone mass in the lumbar spine and 100% of patients with reduced bone mass and 9.1% of patients with normal bone mass in the femoral Ward's triangle. In summary, we found that osteoporosis in postmenopausal women with RA is more evident at the femur than the lumbar spine. Also the important discriminant factors of reduced bone mass postmenopausal women with RA were age, body weight , duration of disease and health disability. In nursing situation, the efforts to improve of functional capacity of postmenopausal women with rheumatoid arthritis should be considered to prevent osteoporosis and fractures. Also we recommend those postmenopausal women with RA who are classified as a group of the reduced bone mass in the discriminant function should examine the bone mineral density to further examine the usefulness of this discriminant function.

• Clinical and Experimental Reproductive Medicine
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• v.31 no.1
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• pp.19-27
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• 2004

Objective: This study was to examine the in vitro neural cell differentiation patterns of human embryonic stem (hES) cells following treatment of various neurotrophic factors [basic fibroblast growth factor (bFGF), retinoic acid (RA), brain derived neurotrophic factor (BDNF) and transforming growth factor (TGF)-$\alpha$], particulary in dopaminergic neuron formation. Methods: The hES cells were induced to differentiate by bFGF and RA. Group I) In bFGF induction method, embryoid bodies (EBs, for 4 days) derived from hES were plated onto gelatin dish, selected for 8 days in ITSFn medium and expanded at the presence of bFGF (10 ng/ml) for another 6 days followed by a final differentiation in N2 medium for 7, 14 and 21 days. Group II) For RA induction, EBs were exposed of RA ($10^{-6}M$) for 4 days and allowed to differentiate in N2 medium for 7, 14 and 21 days. Group III) To examine the effects of additional neurotrophic factors, bFGF or RA induced cells were exposed to either BDNF (10 ng/ml) or TGF-$\alpha$ (10 ng/ml) during the 21 days of final differentiation. Neuron differentiation and dopamine secretion were examined by indirect immunocytochemistry and HPLC, respectively. Results: The bFGF or RA treated hES cells were resulted in similar neural cell differentiation patterns at the terminal differentiation stage, specifically, 75% neurons and 11% glial cells. Additionally, treatment of hES cells with BDNF or TGF-$\alpha$ during the terminal differentiation stage led to significantly increased tyrosine hydroxylase (TH) expression of a dopaminergic neuron marker, compared to control (p<0.05). In contrast, no effect was observed on the rate of mature neuron (NF-200) or glutamic acid decarboxylase-positive neurons. Immunocytochemistry and HPLC analyses revealed the higher levels of TH expression (20.3%) and dopamine secretion (265.5 $\pm$ 62.8 pmol/mg) in bFGF and TGF-sequentially treated hES cells than those in $\alpha$ RA or BDNF treated hES cells. Conclusion: These results indicate that the generation of dopamine secretory neurons from in vitro differentiated hES cells can be improved by TGF-$\alpha$ addition in the bFGF induction protocol.

• Reproductive and Developmental Biology
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• v.35 no.2
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• pp.151-157
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• 2011

Clinical arthritis is typically divided into rheumatoid arthritis (RA) and osteoarthritis (OA). Arthritis-induced muscle weakness is a major problem in aged people, leading to a disturbance of balance during the gait cycle and frequent falls. The purposes of the present study were to confirm fiber type-dependent expression of muscle atrophy markers induced by arthritis and to identify the relationship between clinical signs and expression of muscle atrophy markers. Mice were divided into four experimental groups as follows: (1) negative control (normal), (2) positive control (CFA+acetic acid), (3) RA group (CFA+acetic acid+type II collagen), and (4) aging-induced OA group. DBQA/1J mice (8 weeks of age) were injected with collagen (50 ${\mu}g/kg$), and physiological (body weight) and pathological (arthritis score and paw thickness) parameters were measured once per week. The gastrocnemius muscle from animals in each group was removed, and the expression of muscle atrophy markers (MAFbx and MuRF1) and myosin heavy chain isoforms were analyzed by reverse transcription-polymerase chain reaction. No significant change in body weight occurred between control groups and collagen-induced RA mice at week 10. However, bovine type II collagen induced a dramatic increase in clinical score or paw thickness at week 10 (p<0.01). Concomitantly, the expression of the muscle atrophy marker MAFbx was upregulated in the RA and OA groups (p<0.01). A dramatic reduction in myosin heavy chain (MHC)-$I{\beta}$ was seen in the gastrocnemius muscles from RA and OA mice, while only a slight decrease in MHC-IIb was seen. These results suggest that muscle atrophy gene expression occurred in a fiber type-specific manner in both RA- and OA-induced mice. The present study suggests evidence regarding why different therapeutic interventions are required between RA and OA.

• Food Science and Biotechnology
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• v.18 no.3
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• pp.793-798
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• 2009

The objectives of this present study were to compare the contents and determine optimum extraction conditions for the rosmarinic acid (RA) and caffeic acid (CA) from leaves of Korean Perilla frutescens varieties. RA and CA from leaves of cv. Bora, a breeding line of P. frutescens were isolated and elucidated using various spectroscopic data. On the basis of 2 phenolic acids, optimum extraction conditions were obtained by employing 50% EtOH for 60 min at $25^{\circ}C$. We reported for the first time on the contents of RA and CA from leaves of 32 Korean varieties. Among them, leaves of P. frutescens Brit. var. acuta Kudo I exhibited the highest RA content ($8.53{\pm}0.57$ mg/g) and CA content ($2.33{\pm}0.11$ mg/g) showed the highest in the P. frutescens Brit. var. viridis Makino. Interestingly, average RA content ($2.66{\pm}0.17$ mg/g) showed a markedly higher than that of CA ($1.98{\pm}0.16$ mg/g) in Korean varieties. These results suggest that concentrations of the RA and CA in P. frutescens leaves could be a key factor in the selection process of a high quality species.

• Journal of Radiation Protection and Research
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• v.2 no.1
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• pp.9-16
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• 1977

A simple method has been established for determining RaA, RaB and RaC concentrations in airborne dust. This is to evaluate the concentration from measurement of total alpha activities in three selected-time intervals after an air sample is taken from the membrane filter paper (mean pore size: $0.8{\mu}m$). As a preliminary trial, a time-variation of the concentrations has been determined using the single-filter method at the KAERI site (N. Lat. $37^{\circ}38'$ and E. Long $127^{\circ}15'$), Seoul, Korea. It appears that there is a large variation of the concentrations depending on the sampling time. Generally the highest value was observed in the morning that may coincide with the highest density of atmosphere in a day while the lowest value was obtained around fourteen o'clock.