• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.48 no.6
• /
• pp.28-33
• /
• 2011

Recently, the investigation of the cognitive radio (CR) system is actively progressed as one of the methods for using the frequency resources more efficiently. In CR systems, when the frequency band allocated to the incumbent user is not used, the unused frequency band is assigned to the secondary user. Thus, the FFT input signals corresponding to the actually used frequency band by the incumbent user are assigned as '0'. In this paper, based on the fact that there are many '0' input signals in CR systems, a low-power FFT design method for NC-OFDM is proposed. An efficient zero flag generation technique for each stage is first presented. Then, to increase the utility of the zero flag signals, modified architectures for memory and arithmetic circuits are presented. To verify the performance of the proposed algorithm, 2048 point FFT with radix-24SDFstructureisdesignedusingVerilog HDL. The simulation results show that the power consumption of FFT is reduced considerably by the proposed algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.2
• /
• pp.229-237
• /
• 2016

The purpose of this paper is to empirically identify whether unit bias exists or not under the flat rate pricing in the Korean mobile telecommunication market and to give the desirable form of pricing plans for minimizing this irrational behaviors. Our results show that with the flat rate pricing consumers tends to make more voice or data traffic over their optimal consumption level, meaning the existence of unit bias in the Korean mobile market. These results imply that under the current pricing plans subscribers may pay higher monthly fee than their optimal cost which maximizes their utility, for using the telecommunications service. Thus, policy makers need to consider adopting mobile operators' segmentation of the flat rate pricing plans for the reduction of subscribers' telecommunications costs and the improvement of consumer welfare.

• BMB Reports
• /
• v.54 no.8
• /
• pp.419-424
• /
• 2021

Cold-induced norepinephrine activates β3-adrenergic receptors (β3-AR) to stimulate the kinase cascade and cAMP-response element-binding protein, leading to the induction of thermogenic gene expression including uncoupling protein 1 (Ucp1). Here, we showed that stimulation of the β3-AR by its agonists isoproterenol and CL316,243 in adipocytes increased the expression of Ucp1 and Heme Oxygenase 1 (Hmox1), the principal Nrf2 target gene, suggesting the functional interaction of Nrf2 with β3-AR signaling. The activation of Nrf2 by tert-butylhydroquinone and reactive oxygen species (ROS) production by glucose oxidase induced both Ucp1 and Hmox1 expression. The increased expression of Ucp1 and Hmox1 was significantly reduced in the presence of a Nrf2 chemical inhibitor or in Nrf2-deleted (knockout) adipocytes. Furthermore, Nrf2 directly activated the Ucp1 promoter, and this required DNA regions located at -3.7 and -2.0 kb of the transcription start site. The CL316,243-induced Ucp1 expression in adipocytes and oxygen consumption in obese mice were partly compromised in the absence of Nrf2 expression. These data provide additional insight into the role of Nrf2 in β3-AR-mediated Ucp1 expression and energy expenditure, further highlighting the utility of Nrf2-mediated thermogenic stimulation as a therapeutic approach to diet-induced obesity.

• Asia-Pacific Journal of Business
• /
• v.13 no.1
• /
• pp.37-52
• /
• 2022

Purpose - The objective of this study is to investigate what motivates global FDI inflows in the different economic development level and to clarify the FDI motivation type in the level of qualitative economic growth. Design/methodology/approach - Major macroscopic social·economic factors induced FDI inflows were analyzed using fixed-effect panel regression with 30-year panel data of 28 countries from 1985 to 2014. For analysis in the stage of economic growth, two category of developed and developing countries was used. And to analyze FDI motivation type in the level of qualitative economic growth, 4 shares of GDP; consumption·government·investment expenditure and export, was used as explanatory variable. Findings - In developed country, TFP(total factor productivity) and GDP have a great influence on FDI inflows, and consumption and labor compensation have a slight effect. This result indicates that the market seeking-driven, horizontal type investment is shown along with efficiency seeking investment. In developing country, human capital and TFP is shown to have greater impact on FDI inflows and labor compensation, exports, investment and government expenditures also have impacts. Thus it has confirmed that not only efficiency-seeking vertical investment for using low cost well educated laborer, but also government-driven economic growth and export policies could affect the FDI inflows. Research implications or Originality - The FDI investment decision making of multinational companies is decided by their own purpose. But, in the concept of as follows; 1) FDI is a long-term capital flowing for maximization of economic utility with limited global resource, 2) Thus FDI could be affected by macro socio·economic factors of host country. 3) Also such macro factors is different by each economic growth qualitative level. Therefore macro socio·economic factors of each country could be affected by the qualitative level of their own economic growth. To attract FDI inflows, it is desirable to implement differentiated incentive policies in the qualitative level of economic growth. Furthermore in developing countries it is recommended to implement government driven economic growth policies as follows; fostering well educated human resources, improving technology productivity in the relative lower cost labor market compared to developed countries and boosting international export volume.

• Journal of People, Plants, and Environment
• /
• v.22 no.1
• /
• pp.53-63
• /
• 2019

The purpose of this study was to investigate the preference of plant environmental images for flower plant consumption. This study came up with a total of four treatments including one image without plants and three images with flower plants (three roses, rose gift, rose garden). We conducted a survey on 104 men and women through the Google (online) survey and analyzed the data. The preference was higher with statistical significance for environmental images with plants than the image without plants. The preference for environmental images of roses was highest in the order of rose gift > rose garden > three roses. As a result of the cross-tabulation analysis, it was found that there was a significant difference in the preference for environmental images of roses according to general characteristics such as educational background and residence type. In terms of educational background, 2-year college graduates showed higher preference for the three environmental images of roses with statistical significance compared to high school graduates, university graduates and masters or higher. As a result of determining the difference in preference according to residential types, residents of multiplex houses showed higher preference for the "rose garden" environment image than residents of detached houses (p < .05). As a result of examining stress and depression in everyday life, 48.1% (the highest) of the respondents answered that they were "under daily stress" and 48.1% (the highest) of the respondents claimed not to be "under much depression". This study investigated the difference in preference according to demographic characteristics and existence of plants, preference in environmental images using roses, correlation with daily stress and depression, and utility of publicity using photographic images of plants.

• Journal of the Korean Solar Energy Society
• /
• v.26 no.2
• /
• pp.69-77
• /
• 2006

Photovoltaic is an attractive technology to remote power applications, because of its reliability, low maintenance, and zero fuel requirements. In this paper represents residential PV system based on BESS(battery energy storage system) for managing the electric power, a pattern of daily operation considering the load characteristics of the house, the generation characteristics of PV power, and utility power leveling. For apply to control algorithm, we consider the load on monthly power consumption trend and daily usage pattern. As for the control of the proposed system, to increase the conversion efficiency of the PV power, bidirectional converter is used for MPPT and SPWM inverter. An experimental system is implemented, and some experimental results are provided to demonstrate the effectiveness of the proposed system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.29 no.1
• /
• pp.57-63
• /
• 2015

The incidence of fires caused by electrical factors has increased with the growth in domestic electrical consumption. According to the national fire data system of national emergency management agency, electrical fires accounted for 20% of all domestic fires in the last 10 years. Electrical fires are mainly caused by short circuit, leakage current, defect in an electrical equipment, over load, utility fault, etc. The fault current can be several times larger than the nominal current, thereby exceeding the rated current of cable. Consequently, the cable conductor, typically copper wire, heats up to a temperature that ignites surrounding combustibles. This paper describes the transient characteristics of the 0.6/1kV, TFR-8 cable have been investigated, and analyzed under the over current conditions for reduce the risk of electrical fire by experimental and FEM analysis. The experimental and FEM(Finite Element Method) analysis results of temperature and resistance variation according to the over current in copper wires were analyzed. The experimental results coincide well with the FEM analysis.

• The Korean Journal of Financial Studies
• /
• v.12 no.1
• /
• pp.45-62
• /
• 2006

M. C. Jensen과 W. H. Meckling이 쓴 'The Nature of Man' 논문의 핵심은 역시 REMM(Resourceful Evaluative Maximizing Model)이다. REMM이라는 용어는 새롭지만 개념은 200년 이상의 연구와 경제학과 사회과학과 철학적 토론의 산물이라는 것이다. REMM에서의 핵심은 Resourceful이다. 어떤 이론이나 정책이건 어떤 가정과 한계가 있다는 의미로 사용할 수도 있다. 재무관리의 모태인 경제학에서 지금까지 사용된 모델은 고전 경제학시대부터 일관되어 왔던 추상적 의미의 이익(효용)극대화 모델이다. 재무관리는 그 목적이 궁극적으로 인간의 소비선호체계를(people's consumption preference) 극대화 하는 것이고, 한정된 자원(scare resources)을 시간에 따라 어떻게 배분하여 효용(utility)을 극대화하는 것을 중심과제로 삼고 있다. 효용의 극대화를 위한 자원배분은 생산자원을 어떻게 배합하여 가치생산을 극대화하느냐 하는 생산에의 배분문제와 생산된 재화 및 서비스를 사람들의 욕구충족을 최대로 하는 소비에의 배분문제로 나눠 생각해 볼 수 있다. 그런데 적어도 재무관리에서는 후자는 다루지 않고 가치생산의 문제만 다룬다. 이러한 가정하에서 재무관리의 목표와 이에 따르는 재무관리이론(가정)의 전개는 가치창조와 소비에의 배분을 통한 효용의 극대화를 다루는 경제학의 이론을 답습함으로 일부 혼선을 불러올 수 있다. 위험에 대한 재무담당자(투자자)의 태도를 재무관리의 입장이 아니라 경제현상 전체에 해당되는 입장에서 다루므로 각 각의 교재마다. 투자자의 부 또는 수익에 대한 효용과, 위험과 수익에 대한 무차별곡선이 달리 표현되고 있다. 재무관리 책에서는 재무관리의 가정하에서 투자자의 수익에 대한 효용, 그리고 수익과 위험에 대한 무차별곡선이 정립되어야 할 것이다.

• Journal of Hydrogen and New Energy
• /
• v.28 no.4
• /
• pp.352-360
• /
• 2017

Polygeneration process is widely used to pursuit high efficiency by sharing electricity, utility, refrigeration and the utilization of product chemicals. In this paper, performance analysis of the 450 MW Class polygeneration process was conducted with various syngas generated from coal and biomass gasifier. WGSR and PSA process were employed for hydrogen production and separation. Process modeling and dynamic simulation was carried out, and the results were compared with NETL report. Net power of the polygeneration process was 439 MW considering power consumption. More than 90% of CO was converted at WGSR and the hydrogen purity of PSA was more than 99.99%.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.2
• /
• pp.113-119
• /
• 2011

A frequency in electrical power system changes by the load fluctuation in utility grid, has an influence on a connected generator, and ultimately brings a big trouble in the power system. Therefore, a quick measurement of system frequency and governor control of power system is a very important factor in the reliability and the economic feasibility. Electromagnetic frequency relays in the past had the large power consumption and the difficulty of accurate measurement. After Researched and developed digital relays are very affected by the noise and the distortion, and the recently developed Microprocessor relays have problems of expensive device and time when measuring the frequency at 50[ms]. In this study, An improve algorithm that measures the power system frequency quickly and accurately is suggested, simulated by using Matlab and programmed using C code through DSP6713 KIT. This algorithm is tested to the arbitrary voltage waveform input. The results show that the suggested algorithm is effective in the accurate and quick frequency measurements.