• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.10
• /
• pp.2165-2170
• /
• 1997

In this paepr, the distortion effects of impairments in CDMA transmitter system were analyzed. We considered not only linear distortion effects, for example, I/Q imbalance, quadrature offset and carrier leakage, but also nonlinear distortion effects such as AM-AM and AM-PM noise in power amplifier. To investigate how the impariments impact on the performance of CDMA transmitter, all effects represented as a function of CDMA modulation quality which is an important measure of the transmitted signal. These results show the limitation value of each impairment which is required to satisfy the IS-95 standard.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.16 no.3
• /
• pp.19-30
• /
• 2013

This study was proposed to adaptable species according to climate change using warmth index(WI) in Cheonan-Si. RCP 8.5 was used to estimate change of warmth index(WI) depending on climate change in Cheonan-Si. Climatic change of Cheonan-Si was estimated to change from cool temperate forest central zone to warm temperate forest zone. The following plant species will survive within WI change of Cheonan-Si from 2010 to 2050 : 18 species in the tree layer including Quercus serrata, Q. variabilis, Pinus densiflora, Q. acutissima etc.; 28 species in the shrub layer including Rhus trichocarpa, Lindera obtusiloba, Zanthoxylum schinifolium etc.; 24 species in the herb layer including Oplismenus undulatifolius, Carex lanceolata, etc.; 12 species in the vine plants including Smilax china, Cocculus trilobus, etc.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.19 no.1
• /
• pp.143-148
• /
• 2024

Traffic congestion has caused issues in various forms such as the environment and economy. Recently, an intelligent transport system (ITS) using artificial intelligence (AI) has been focused so as to alleviate the traffic congestion problem. In this paper, we propose a reinforcement learning-based traffic signal control algorithm that can smooth the flow of traffic while reducing discomfort levels of drivers and pedestrians. By applying the proposed algorithm, it was confirmed that the discomfort levels of drivers and pedestrians can be significantly reduced compared to the existing fixed signal control system, and that the performance gap increases as the number of roads at the intersection increases.

• Korean Journal of Food Science and Technology
• /
• v.49 no.1
• /
• pp.90-96
• /
• 2017

The aim of this study was to investigate the anti-inflammatory and ultraviolet (UV)-protective effect of Pleurotus eryngii extract (PEE) in activated RAW 264.7 cells and UV-induced mouse skin damage. The results showed that PEE strongly inhibited the production of inflammatory mediators such as nitric oxide, interleukin $(IL)-1{\beta}$, and IL-6 at high concentrations in LPS-stimulated RAW 264.7 macrophages. In addition, PEE treatment suppressed erythema, melanin index, and epidermal thickness to a greater degree than ascorbic acid (AA) treatment in UV-irradiated mice. Finally, PEE treatment inhibited the infiltration of mast cell to a similar degree of AA treatment. Therefore, these results indicate that PEE could improve inflammation and skin damage in immune cells and UV-irradiated mice. This study may provide positive insights into PEE as a functional food and cosmetic ingredient for treatment of inflammation and skin damage.

• Journal of the Korean Magnetics Society
• /
• v.10 no.3
• /
• pp.99-105
• /
• 2000

One dimensional magneto-photonic crystal having structure of (A/B)$^{k/W}$(B/A)$^{k}$ , where M is a magnetic layer of highly Bi-substituted iron garnet, A and B are dielectric layers of $SiO_2$ and T $a_2$O$_{5/}$, and k is the stacking number of the dielectric layers, has been numerically analyzed as a function of the thickness (d$_{M}$) of M (1∼535 nm) and the stacking numer of k (5∼15). The transmittance, Faraday rotation, and figure of merit of the magneto-photonic crystal have been investigated both in the visible and infrared wavelengths. A factor of several and several tens greater Faraday rotation and figure of merit have been obtained compared to the single layer of M, at many localized modes. In the visible the maximum figure of merit of 0.15 was obtained ( = 720 nm) when k = 11 and d$_{M}$ = 375 nm with T : 0.54, $\theta$$_{F}$ = 8.13$^{\circ}$, which was a factor of 30 greater than that of single garnet layer. Much greater maximum figure of merit, 0.285, was obtained in the infrared ( = 1114 nm) when k = 11 and d$_{M}$ = 800 nm with T = 0.66, $\theta$$_{F}$ = 18$^{\circ}$, which was a factor of 100 greater than that of single garnet layer.

• Land and Housing Review
• /
• v.11 no.2
• /
• pp.33-46
• /
• 2020

As the fastest growing office transaction volume in Korea, there's been a need for development of indicators to accurately diagnose the office capital market. The purpose of this paper is experimentally calculate to the office price index for effective benchmark indices in Seoul. The quantitative methodology used a Case-Shiller Repeat Sales Model (1991), based on actual multiple office transaction dataset with over minimum 1,653 ㎡ from Q3 1999 to 4Q 2019 in the case of 1,536 buildings within Seoul Metropolitan. In addition, the collected historical data and spatial statistical analysis tools were treated with the SAS 9.4 and ArcGIS 10.7 programs. The main empirical results of research are briefly summarized as follows; First, Seoul office price index was estimated to be 344.3 point (2001.1Q=100.0P) at the end of 2019, and has more than tripled over the past two decades. it means that the sales price of office per 3.3 ㎡ has consistently risen more than 12% every year since 2000, which is far above the indices for apartment housing index, announced by the MOLIT (2009). Second, between quarterly and annual office price index for the two-step estimation of the MIT Real Estate Research Center (MIT/CRE), T, L, AL variables have statistically significant coefficient (Beta) all of the mode l (p<0.01). Third, it was possible to produce a more stable office price index against the basic index by using the Moore-Penrose's pseoudo inverse technique at low transaction frequency. Fourth, as an lagging indicators, the office price index is closely related to key macroeconomic indicators, such as GDP(+), KOSPI(+), interest rates (5-year KTB, -). This facts indicate that long-term office investment tends to outperform other financial assets owing to high return and low risk pattern. In conclusion, these findings are practically meaningful to presenting an new office price index that increases accuracy and then attempting to preliminary applications for the case of Seoul. Moreover, it can provide sincerely useful benchmark about investing an office and predicting changes of the sales price among market participants (e.g. policy maker, investor, landlord, tenant, user) in the future.

• Journal of the Korean Geotechnical Society
• /
• v.26 no.7
• /
• pp.7-16
• /
• 2010

Stress history increases the residual horizontal stress of granular soil and, consequently, the penetration resistance. This study analyzes the effect of stress history on the cone resistance ($q_c$), horizontal stress index ($K_D$) and dilatometer modulus ($E_D$) of CPT and DMT from calibration chamber specimen in OC as well as NC state. Test results show that the normalized cone resistance by mean effective stress correlates well with the relative density and the state parameter, whereas the normalized cone resistance by vertical effective stress is a little affected by stress history. The influence of stress history is more reflected on $K_D$ than $E_D$ and $q_c$. The $K_D/K_0$, in which the effect of stress history on $K_D$ is compensated by the at-rest coefficient of earth pressure, $K_0$, is related to relative density, state parameter and the normalized cone resistance by mean effective stress. It is also observed that the normalized dilatometer modulus by mean effective stress ($E_D/{\sigma}_m'$) shows a unique correlation with the state parameter, regardless of stress history.

• Journal of Chest Surgery
• /
• v.39 no.9 s.266
• /
• pp.674-680
• /
• 2006

Background: Acute myocardial infarction (MI) is a life-threatening disease and surgical revascularization plays a major role in selected cases. The purpose of this study is to evaluate the left ventricular contractility improvement by examining the wall motion score index (WMSI) and left ventricular ejection fraction (LVEF) in patients who under-went surgical revascularization under diagnosis of acute MI. Material and Method: From January, 2001 to December, 2004, 149 patients who underwent coronary artery bypass surgery within 2 weeks of acute MI were included. We evaluated pre- and postoperative left ventricular contractility by measuring WMSI and LVEF and examined the associating factors. Result: WMSI decreased from $1.54{\pm}4.30\;to\;1.43{\pm}0.40$ (p<0.001) and LVEF increased from $48.1{\pm}12.2%\;to\;49.7{\pm}12.3%$ after surgery (p=0.009). Off-pump technique, non-Q wave, anterior MI, and surgery within 7 days after MI were favorable factors for LVEF improvement (p=0.046, p=0.006, p=0.003, p=0.005, respectively). Conversely, aforementioned factors were irrelevant with WMSI improvement. For triple vessel disease, complete revascularization was favorable factor for WMSI improvement (p<0.001). Conclusion: Coronary artery by-pass surgery can improve WMSI and LVEF in patients with acute MI. In case of anterior MI with non-Q wave, early surgical revascularization within 7 days may be most beneficial in LVEF improvement. Regarding WMSI, complete revascularization may be essential.

• Korean Journal of Materials Research
• /
• v.5 no.3
• /
• pp.371-378
• /
• 1995

YBCO 산화물 초전도체의 초소성 변형에 대한 최적 변형조건을 파악하고자 80$0^{\circ}C$~93$0^{\circ}C$의 온도범위에서 1.0 $\times$ $10^{-3}$s^{-1}$!1.0 $\times$ $10^{-7}$s^{-1}$의 초기변형속도로 압축시험을 수행하였다. 변형속도 민감지수는 m=0.50 $\pm$ 0.1로 나타났다. 이는 결정립계 미끄러지\ulcornerㄹ 주 변형기구로 하는 초소성임을 의미한다. 결정립크기에 따른 유동응력과의 관계는 $\sigma$\propto$d^{1.8 $\pm$ 0.3}$의 지수함수식을 이루고 있으며 Nabarro-Hering 크\ulcorner과 상응하는 격자확산이 확산경로임을 보였다. 초소성 변형에 대한 활성화에너지는 Q=571 $\pm$ 30 kJ/mole이었다. 본 실험온도 구간에서 압축 변형시 변형속도, 변형응력 및 결정립크기에 따른 고온 변형거동 관계식은 $\varepsilon$=A$\sigma$^{2.00 $\pm$ 0.04 - 1.8 $\pm$ 0.3}$ exp(-571 $\pm$ 30kJ/RT)와 같이 유도 되었다. 본 실험조건에서 최적 초소성 변형조건은 86$0^{\circ}C$ 부금, 초기변형속도 ~1.0 $\times$ $10^{-4}$S^{-1}$이었다.

• Journal of Korean society of Dental Hygiene
• /
• v.10 no.6
• /
• pp.1015-1024
• /
• 2010

Objectives : This study was to investigate the level of health risk behavior, athletes stress, quality of life(WHOQOL-BREF) and oral health related quality of life(OHIP-14) and the clinical factors influencing quality of life in athletes Methods : Data were obtained from a cross-sectional survey of 202 university athletes. Data was obtained by means of questionnaire from October 11 to October 15, 2010. Health risk behaviors(Q-F index and smoking), athletes stress, WHOQOL-BREF and OHIP-14 were measured. The data was analysed with t-test, one-way ANOVA, Pearson correlation coefficient and multiple regression using the SPSS program. Results : The prevalence of alcohol drinking, smoking were 84.2% and 37.9%, respectively. Alcohol drinking and cigarette consumption were not related to quality of life though there were the negative correlation between athletes stress and quality of life. Powerful predictors of quality of life were athletes stress, OHIP-14 and perceived health for athletes. Conclusions : Based on the findings, quality of life has a significantly impact on athletes stress, OHIP-14 and perceived health. These results suggest that the implementation of health promotion program should be considered which was decreased athletes stress and was increased level of oral health and perceived health in athletes.