• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.27 no.4
• /
• pp.369-376
• /
• 2016

In this paper, we propose and design a SSD(Simultaneous Single band Duplex) system using 5G(Generation) candidate modulations. Especially, we consider HPA(High Power Amplifier) nonlinearity in the proposed system. And then, we evaluate and analyze performance of the proposed system. As simulation results, performance of SSD-OFDM(Orthogonal Frequency Division Multiplexing), SSD-FMC (Universal Filtered Multi-Carrier), and SSD-FBMC(Filter Bank Multi-Carrier) is severely degraded by HPA nonlinearity. However, performance of SSD-OFDM, SSD-UFMC, and SSD-FBMC is similar in the same condition. That is, OFDM, UFMC, and FBMC have a similar PAPR(Peak to Average Power Ratio) characteristic. Finally, we can confirm that the proposed SSD system can not cancel(SI) self-interference effectively by strong HPA nonlinearity. That is, Reducing PAPR is important in order to avoid effect of HPA nonlinearity in the proposed SSD system.

• Korean Journal of Heritage: History & Science
• /
• v.48 no.1
• /
• pp.132-147
• /
• 2015

In this article, the research trends regarding the analysis and restoration of the pigments applied on colored cultural properties during past 25 years are reviewed and the future research direction in this field of study is proposed. There are over 100 different pieces of the colored cultural property samples that have been analyzed in Korea during the time and are increasing numbers of studies on comparative investigations as well. In addition, new analysis techniques have been introduced to surpass the limitation of the current analysis techniques and the database construction has been developed tremendously, which will enhance the analysis reliability, indicating fast growth in the related research areas. There are also studies on finding new materials to replace the traditional ingredients for producing color pigments and related other materials to overcome the limitation of the traditional ingredients on top of the steady number of studies on reproduction and restoration of the traditional pigments. These various research efforts will bring much development in this area of research. One suggestion to be made is that there need to be long term planned research works for certain type of studies. For instance, the effect to the colored cultural properties due to the environmental change is one of important research topics that should be carefully studied, which requires longer time period and also more patience than the research works in the current and past trends.

• Journal of Labour Economics
• /
• v.41 no.4
• /
• pp.63-105
• /
• 2018

This paper analyzes the effects of three factors on the firm-size wage premium which have not been considered in previous studies: the worker compositions within firms, the wage differentials between contractors and subcontractors, and the performance pay and rent-sharing behaviors of firms. The main results are as follows. First, even after controlling for the various worker characteristics, the differences in shares of highly educated workers, managers, and professionals between large and small firms make the size-wage premium larger. Secondly, wage differentials between contractors and subcontractors also affect the size-wage premium in the manufacturing sector. Thirdly, high performance pay and active rent-sharing behaviors of large manufacturing firms make the size-wage premium larger. These results imply that a positive matching effect among skilled workers, a structural problem between contractors and subcontractors, and differences in rent-sharing behaviors between large and small firms have affected the firm-size wage premium in the South Korean labor market.

• The Journal of Asian Finance, Economics and Business
• /
• v.8 no.4
• /
• pp.83-91
• /
• 2021

Health is an outset of psychological, social, financial, and physical state. Several macroeconomic factors are entangled with health and mortality. Infant mortality and life expectancy are two keyguard on demographic research context on last few decades. On the other hand, foreign inflows play an unprecedent role for raising economic circulation and providing more opportunities to build a better society. The study aims to investigate the relationship between foreign direct investment (FDI), economic growth, and Bangladesh's health. This study employs time-series data from 1980 to 2018. Results show, with Auto-regressive Distribute Lag (ARDL) model, that there is significant cointegration among variables. Foreign investment and economic output relate significantly and positively to health. On the contrary, education is quasi-linked with a different sign-on different model. For model validation, pitfalls of time-series multicollinearity, heteroscedasiticy, and autocorrelation are not present. Also, CUSUM and CUSUMSQ tests are validating the model as stable and fit for future prediction. Medical assessment and education need more attention from the government as well as the private sector. FDI can play a catalyst role for improving the health sector, raising opportunity in educating and creating a better lifestyle. In order to optimize foreign investment, the government should implement necessary reforms and policies.

• The Korea Journal of Herbology
• /
• v.32 no.6
• /
• pp.9-15
• /
• 2017

Objectives : Traditional medicines isolated from natural products often have positive effects in the prevention and healing of various immune disorders, such as allergy and atopic inflammation. Scrophulariae Radix (SR) been used in oriental medicine used for treatment of acute and chronic inflammatory diseases. Mast cells are known to play important roles in the initiation of allergic reactions. In this study, we investigated the effects of SR ethanol extract on inflammatory responses in IgE-stimulated RBL-2H3 mast cells. Methods : Rat basophilic leukemia RBL-2H3 cells were purchased from Korean Cell Line Bank (KCLB No. 22256). Cell viability was measured by MTT assay. Assays for ${\beta}-Hexosaminidase$ Secretion : RBL-2H3 cells were sensitized with dinitrophenyl-ImmunoglobulinE (DNP IgE). The next antigen DNP-BSA ($25ng/m{\ell}$) was added for 10 minutes and the reaction was terminated after 5 minutes in the ice bath. To determine ${\beta}-Hexosaminidase$ release, supernatants were aliquoted into 96-well plates. Samples were mixed with substrate solution and incubated for 1 h at $37^{\circ}C$. Absorbance was measured with a spectrophotometer at 405 nm. IL-4 and tumor necrosis $factor-{\alpha}$($TNF-{\alpha}$) concentrations in cell culture supernatants were measured using enzyme-linked immunosorbent assay (ELISA) kits. Results : The cytotoxicity of SRE in RBL-2H3 cells was less than 5%. SRE inhibited DNP-IgE-imduced degranulation of mast cells in RBL-2H3 cells. Also significantly decreased the levels of inflammatory cytokine, IL-4 and TNF-alpha. In this study, the SRE showed potential anti-allergic and antiinflammatory. Conclusions : These results indicate that SRE could be inhibit the allergic response through suppressing the mast cell activation.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.294-294
• /
• 2022

In 2013, the Asian Development Bank classified the Philippines among the countries facing high food security risks. Evidence has suggested that climate change has affected agricultural productivity, and the effect of extreme climatic events notably drought has worsened each year. This had resulted in serious hydrological repercussions by limiting the timely water availability for the agriculture sector. Laguna is the 3^rd most populated province in the country, and it serves as one of the food baskets that feed the region and nearby provinces. In addition to climate change, population growth, rapid industrialization, and urban encroachment are also straining the delicate balance between water demand and supply. Studies have projected that the province will experience less rainfall and an increase in temperature, which could simultaneously affect water availability and crop yield. Hence, understanding the composite threat of climate change for crop yield and water consumption is imperative to devise mitigation plans and judicious use of water resources. The water footprint concept elaborates the water used per unit of crop yield production and it can approximate the dual impacts of climate change on water and agricultural production. In this study, the water footprint (WF) of six main crops produced in Laguna were estimated during 2010-2020 by following the methodology proposed by the Water Footprint Network. The result of this work gives importance to WF studies in a local setting which can be used as a comparison between different provinces as well as a piece of vital information to guide policy makers to adopt plans for crop-related use of water and food security in the Philippines.

• Economic Analysis
• /
• v.26 no.4
• /
• pp.65-97
• /
• 2020

The purpose of this paper is to analyze the effects of exports on Korea's employment and to decompose driving factors of change in Korea's employment embodied in exports (EEX). This study uses a multi-regional input-output (MRIO) and structural decomposition analysis (SDA) for empirical analysis, and uses a dataset of World Input-Output Tables (WIOTs) and Socio-Economic Accounts (SEAs) from the World Input-Output Database (WIOD). The main findings of the empirical results are summarized as follows. First, Korea's EEX continues to increase and Korea's share of EEX compared to total employment shows an upward trend. However, Korea's employment inducement coefficient of value-added exports showed a downward trend during the 2000-2014 period. Second, final demand from three countries (China, the United States, and the Rest of the World (RoW)) has affected a significant portion of Korea's EEX. Finally, from the results of the SDA, the effect of changes in final demand was the most important driving factor for the increase in Korea's EEX. Based on the results of this empirical analysis, this study discusses useful policy implications that could increase domestic employment in Korea.

• Journal of Korea Trade
• /
• v.26 no.7
• /
• pp.127-144
• /
• 2022

Purpose - This study aimed to analyze the dynamic effects of progress in globalization on firm performance by employing individual companies' financial statement datasets. Design/methodology - The analysis leveraged the variables of operating revenue (OPRE) and pre-tax profit and loss (PLBT) as measurement variables for firm performance over 2011-2019. As a proxy variable for globalization, the trade index, a subordinate indicator of the KOF Globalization Index, was used. Through panel regression analysis, the relationship among those variables was ascertained, and the local projection (LP) method was subsequently utilized to identify dynamic effects. A subsample analysis was further performed by classifying companies based on their sizes and industries to determine the differential effects of globalization on each group. Findings - The panel regression analysis derived positive effects of an increasing degree of globalization on OPRE of Korea maritime and fishery firms. However, the impulse response functions, obtained from the LP, showed that in the short run, globalization affects PLBT negatively but in the long run, it gradually converted into a positive effect. In addition, according to the subsample analysis based on company size, the effects of globalization on OPRE became greater as each company became larger. Moreover, the industry-based analysis showed heterogeneous effects, depending on the industries in which the maritime and fishery companies operated. Originality/value - The analysis of the dynamic effects of globalization on firm performance, which revealed that the effects vary depending on the time points, is the important contribution of this study. The results also suggest that the effects of globalization vary depending on the company size and industry.

• Korea Trade Review
• /
• v.43 no.2
• /
• pp.23-45
• /
• 2018

Logistic costs refer to trade costs, but it could influence FDI as well as global trade. Multinational corporations choose the geographic organization to produce their products. Therefore, it involves many countries to produce one product. International trade between countries more frequently involves the trade of raw materials, components, and unfinished goods. This implies that countries with better logistic performance are attractive for investment because of low transaction costs. Using the logistic performance index provided from the World Bank, this paper investigates the impacts of logistic performance on FDI inflow to developing countries. Results show that infrastructure and timeliness have a positive effects on FDI inflow to low income countries. In the case of middle income countries, timeliness has a negative effect on FDI inflow. This discrepancy between the low- and middle- income countries comes from the different motivation. FDI for low income countries primarily attempts to minimize labor costs. However, FDI for middle-income countries seems to be motivated to reduce labor costs and expand sales markets. FDI inflow in low-income countries serves as part of the offshoring or global outsourcing of multinational corporation.