• 한국수학교육학회지시리즈A:수학교육
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• 제21권3호
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• pp.7-11
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• 1983

A measurable function f defined on a measurable subset A of the real line R is called pth power summable on A if │f│$^{p}$ is integrable on A and the set of all pth power summable functions on A is denoted by L$^{p}$ (A). For each member f in L$^{p}$ (A), we define ∥f∥$_{p}$ =(equation omitted) For real numbers p and q where (equation omitted) and (equation omitted), we discuss the Holder's inequality ∥fg∥$_1$<∥f∥$_{p}$ ∥g∥$_{q}$ , f$\in$L$^{p}$ (A), g$\in$L$^{q}$ (A) and the Minkowski inequality ∥＋g∥$_{p}$ <∥f∥$_{p}$ ＋∥g∥$_{p}$ , f,g$\in$L$^{p}$ (A). In this paper also discuss that L$_{p}$ (A) becomes a metric space with the metric $\rho$ : L$^{p}$ (A) $\times$L$^{p}$ (A) longrightarrow R where $\rho$(f,g)=∥f-g∥$_{p}$ , f,g$\in$L$^{p}$ (A). Then, in this paper prove the Riesz-Fischer theorem, i.e., the space L$^{p}$ (A) is complete and that the space L$^{p}$ (A) is separable.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.269-269
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• 2012

A new ion source has been designed, fabricated, and installed at the NBTS (Neutral Beam Test Stand) at the KAERI (Korea Atomic Energy Research Institute) site. The goalis to provide a 100 keV, 2MW deuterium neutral beam injection as an auxiliary heating of KSTAR (Korea Super Tokamak Advanced Research). To cope with power demand, an ion current of 50 A is required considering the beam power loss and neutralization efficiency. The new ion source consists of a magnetic cusp bucket plasma generator and a set of tetrode accelerators with circular copper apertures. The plasma generator for the new ion source has the same design concept as the modified JAEA multi-cusp plasma generator for the KSTAR prototype ion source. The dimensions of the plasma generator are a cross section of $59{\times}25cm^2$ with a 32.5 cm depth. The anode has azimuthal arrays of Nd-Fe permanent magnets (3.4 kG at surface) in the bucket and an electron dump, which makes 9 cusp lines including the electron dump. The discharge properties were investigated preliminarily to enhance the efficiency of the beam extraction. The discharge of the new ion source was mainly controlled by a constant power mode of operation. The discharge of the plasma generator was initiated by the support of primary electrons emitted from the cathode, consisting of 12 tungsten filaments with a hair-pin type (diameter = 2.0 mm). The arc discharge of the new ion source was achieved easily up to an arc power of 80 kW (80 V/1000 A) with hydrogen gas. The 80 kW capacity seems sufficient for the arc power supply to attain the goal of arc efficiency (beam extracted current/discharge input power = 0.8 A/kW). The accelerator of the new ion source consists of four grids: plasma grid (G1), gradient grid (G2), suppressor grid (G3), and ground grid (G4). Each grid has 280 EA circular apertures. The performance tests of the new ion source accelerator were also finished including accelerator conditioning. A hydrogen ion beam was successfully extracted up to 100 keV /60 A. The optimum perveance is defined where the beam divergence is at a minimum was also investigated experimentally. The optimum hydrogen beam perveance is over $2.3{\mu}P$ at 60 keV, and the beam divergence angle is below $1.0^{\circ}$. Thus, the new ion source is expected to be capable of extracting more than a 5 MW deuterium ion beam power at 100 keV. This ion source can deliver ~2 MW of neutral beam power to KSTAR tokamak plasma for the 2012 campaign.

• 한국위성정보통신학회논문지
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• 제10권4호
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• pp.71-76
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• 2015

본 연구는 LTE, 5G의 무선 통신네트워크망에서 효율적으로 무선에너지하비스팅과 데이터 전송 실시하기 위한 시스템 모델을 제시한다. 수신 된 신호의 파워를 타임 스위칭(Time Switching)과 파워 스플릿팅(Power Splitting) 기법을 통해 우리가 원하는 무선에너지하비스팅 효율과 데이터 전송률을 만족시키기 위한최적의 타암 & 파워 비율을 찾는다. 그래서 최적의 시간 & 파워 비율을 선정함으로써 우리는 효율적으로 데이터 전송과 에너지하비스팅이 가능하다. 또 이상적인 수신기와 제안한 시스템 모델의 비교를 통해 성능 분석을 실시하고, 앞으로의 연구방향을 제시한다.

• International journal of advanced smart convergence
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• 제9권2호
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• pp.68-75
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• 2020

Non-orthogonal multiple access (NOMA) has gained the significant attention in the fifth generation (5G) mobile communication, which enables the advanced smart convergence of the artificial intelligence (AI), the internet of things (IoT), and many of the state-of-the-art technologies. Recently, correlated superposition coding (SC) has been proposed in NOMA, to achieve the near-perfect successive interference cancellation (SIC) bit-error rate (BER) performance for the stronger channel users, and to mitigate the severe BER performance degradation for the weaker channel users. In the correlated SC NOMA scheme, the stronger channel user BER performance is even better than the perfect SIC BER performance, for some range of the power allocation factor. However, such excessively good BER performance is not good for the user-fairness, i.e., the more power to the weaker channel user and the less power to the stronger channel user, because the excessively good BER performance of the stronger channel user results in the worse BER performance of the weaker channel user. Therefore, in this paper, we propose the power splitting to establish the user-fairness between both users. First, we derive a closed-form expression for the power splitting factor. Then it is shown that in terms of BER performance, the user-fairness is established between the two users. In result, the power splitting scheme could be considered in correlated SC NOMA for the user-fairness.

• 한국지역사회생활과학회지
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• 제21권4호
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• pp.641-649
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• 2010

To make sure of the usefulness of extract of Rubus coreanus Miquel for producing functional feeding honey, we compared some antioxidative indicators of feeding honey using extract of Rubus coreanus Miquel with acacia honey, SueBee Clover honey(USA), feeding honey on the market. The water content of four honeys were 16.6~26.5%, pH were 3.18~3.70, and titratable acidity ranged 0.018~0.022%. The phenolic compound contents of SueBee Clover honey and feeding honey using extract of Rubus coreanus Miquel were 8.3 mg/100 g and 7.3 mg/100 g, respectively, and were significaltly higher thgheacacia honey and feeding honey on the market. The flavonoid contents per 100 g of honey ranged from 2.3 mg(acacia honey) to 15.0 mg(SueBee Clover honey). DPPH anion scavenging activity of four honeys were not high. 0.5~2.0 g/ml of feeding honey using extract of Rubus coreanus Miquel was 16~36% and showed a concentration-reliant figure. At the concentration of 0.25~0.75 mg/ml, the reducing power of four honeys increased concentration-dependently, and the power of 0.25 mg/ml of feeding honey using extract of Rubus coreanus Miquel was corresponding to thgt of $150{\mu}g$/ml of a vitamin C solution. ABTS radical scavenging activity of feeding honey using extract of Rubus coreanus Miquel was 43.3~68.4%; the highest activity amongst all samples. When plotting the dose-response curve, ABTS radical scavenging activity also increased as their concentration increased from 62.5 mg/ml to 500 mg/ml. The heat treatment reduced the phenolic compound contents of acacia honey and feeding honey using extract of Rubus coreanus DPPH anion scavenging activity of feeding honey on the market and feeding honey using extract of Rubus coreanus Miquel did not changed significaltly after heating for 20 min, and the three honey except SueBee Clover honey maintained the reducing power with the same treatment.

• 한국전자파학회논문지
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• 제16권8호
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• pp.810-814
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• 2005

TEM 셀 내에 있는 혈액에 대한 삽입 손실과 반사율을 측정하여, 원하는 혈액 흡수 SAR(Specific Absorption Rate) 선택에 따른 TEM셀 입력 전력을 구하였다. 혈액 세포는 피부 세포와 함께 전자파 영향을 연구하기 위한 기준 세포이다. 따라서 SAR에 따른 혈액 세포에 인가할 전력 산출은 정확해야 함은 물론 타당성이 있어야 한다. 이 연구에서는 g당 혈액 세포가 받는 전력을 산출하기 위해 50 g의 혈액을 이용하여 전달 전력 감소를 측정하였다. 측정된 데이터로부터 휴대폰 전자파 생체 흡수율 SAR 0.8, 1.6, 3, 4 mW/g에 해당하는 TEM셀 입력 전력을 계산하였다. 이 연구 결과는 배양 세포의 전자파 방사 장치에 응용함을 목적으로 하고 있다.

• 한국대기환경학회지
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• 제31권5호
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• pp.461-471
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• 2015

Base on emission factors derived from National Institute of Environmental Research, Particulate matter from combined cycle power plants (CCPPs) has been estimated to be a important source of $PM_{10}$. Generally there is no serious emission of particulate matter in CCPPs. because the fuel of them is natural gas. But emission gas after long shut down season has very high dust content. Therefore $PM_{10}$ emission rate is dependent on its operation mode. In this study, particulate dispersion study for new city near CCPPs complex has performed using CALPUFF model for three case. $PM_{10}$ concentration has big difference between normal operation and 2 case start-up condition after long shutdown. In normal operating conditions, daily $0.32{\sim}0.50{\mu}g/m^3$ influence on of the surrounding area. But when 1~2 aerobic high concentration discharged conditions, average concentration is higher about $9.2{\sim}34.1{\mu}g/m^3$ than normal operating conditions.

• 전력전자학회논문지
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• 제20권1호
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• pp.31-37
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• 2015

This paper proposes a 3.3-kW bi-directional EV charger with V2G and V2H functions. The bi-directional EV charger consists of a DC-DC converter and a DC-AC inverter. The proposed EV charger is suitable for wide battery voltage control due to the two-stage configuration of the DC-DC converter. By employing a fixed-frequency series loaded resonant converter as the isolated DC-DC converter, zero-current-switching can be achieved regardless of battery voltage variation, load variation, and power flow. A 3.3-kW prototype of the proposed EV charger has been built and verified with experiments, and indicates a maximum efficiency of 94.39% and rated efficiency of 94.23%.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.30-33
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• 1997

In this paper, we studied the variation in optical constants of Te-doped G $e_{15}$ /$Sb_{85}$ thin films with 7800$\AA$ diode-laser exposing time and power. The reflectances were increased with the increase of laser exposure time and the laser power in all films. Also, the refractive indices of the films after exposing were higher than those of the as-deposited films. Thus, the fast crystallization was caused by addition to the more Te content at the lower lacer power. It was observed that the surface morphologies of the exposed films are higher than those of the as-deposited films by SEM analysis. Therefore, it is considered that the T $e_{0.5}$(G $e_{15}$ /$Sb_{85}$)$_{99.5}$ thin films will show the high contrast ratio and high SNR and have fast erasing time due to crystallization when these films is applied to optical recording materials.terials.s.

• Journal of Platform Technology
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• 제11권1호
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• pp.3-10
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• 2023

최근 Unmanned Aerial Vehicles (UAVs)은 높은 유동성 및 낮은 하드웨어 비용으로 5G, 6G 무선 통신에서 큰 관심을 받고 있다. 여전히 Blockage와 에너지 문제가 존재하지만 이러한 문제들은 Reconfigurable Intelligent Surface (RIS)를 활용하여 해결할 수 있다. 또한 RIS를 UAV 통신에 이용함으로써 신호를 받지 못하는 사용자에게 신호를 전송하여 Spectral Efficiency를 향상시키며, 에너지 소비를 줄일 수 있다. 현재 대부분의 연구들은 송신 전력과 RIS 위상을 교대로 최적화하여 Power Consumption 최소화 및 데이터 전송 Delay 최소화 등의 목적을 달성하였다. 본 논문에서는 대역폭 최적화를 포함하여 합산 정보 전달율을 최대화하는 알고리즘을 제안한다. 이에 대한 성능평가를 진행하였고, 시뮬레이션을 통해 제안한 알고리즘의 우수성을 보였다.