• 경영과학
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• 제30권3호
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• pp.1-16
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• 2013

In this paper, we deal with an enhanced index fund strategy by implementing the exchange trade funds (ETFs) within the context of the Black-Litterman approach. The KOSPI200 index ETF is used to build risk-controlled portfolio that tracks the benchmark index, while the proposed Black-Litterman model mitigates estimation errors in incorporating both active investment views and equilibrium views. First, we construct a Black-Litterman model portfolio with the active market perspective based on the momentum strategy. Then, we update the portfolio with the KOSPI200 index ETF by using the equilibrium return ratio and weighted averages, while devising optimization modeling for improving the information ratio (IR) of the portfolio. Finally, we demonstrate the empirical viability of the proposed enhanced index strategies with KOSPI 200 data.

• 전기학회논문지
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• 제59권6호
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• pp.1120-1125
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• 2010

In the speech system, for example hearing aid as well as speech communication, speech quality is degraded by environmental noise. In this study, to enhance the speech quality which is degraded by environmental speech, we proposed an algorithm to reduce the noise and reinforce the speech. The minima controlled recursive averaging (MCRA) algorithm is used to estimate the noise spectrum and spectral weighting factor is used to reduce the noise. And partial masking effect which is one of the human hearing properties is introduced to reinforce the speech. Then we compared the waveform, spectrogram, Perceptual Evaluation of Speech Quality (PESQ) and segmental Signal to Noise Ratio (segSNR) between original speech, noisy speech, noise reduced speech and enhanced speech by proposed method. As a result, enhanced speech by proposed method is reinforced in high frequency which is degraded by noise, and PESQ, segSNR is enhanced. It means that the speech quality is enhanced.

• 센서학회지
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• 제27권5호
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• pp.275-279
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• 2018

In this study, we introduce a sensing platform based on a plasmonic metasurface absorber (MA) with a vertical nanogap for the ultrasensitive detection of monolayer molecules. The vertical nanogap of the MA, where the extremely high near-field is uniformly distributed and exposed to the external environment, is formed by an under-cut structure between a metallic cross nanoantenna and the mirror layer. The accessible sensing area and the enhanced near-field of the MA further enhance the sensitivity of surface-enhanced infrared absorption for the target molecule of 1-octadecanethiol. To provide strong coupling between the molecular vibrations and plasmonic resonance, the design parameters of the MA with a vertical nanogap are numerically designed.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2013년도 하계학술대회
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• pp.3-5
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• 2013

본 논문에서는 enhanced aacPlus 부호화기의 스펙트럼 계수 무손실 부호화에 arithmetic coding을 적용하여 비트율을 감소시키는 방법을 연구하였다. USAC의 arithmetic coding을 enhanced aacPlus 구조에 맞게 변경하여 적용하였다. 기존 방법과 arithmetic coding 방법에 의한 부호화 비트 수를 비교하여 성능을 평가하였고, 모노 신호에서 최대 9.3%, 스테레오 신호에서 최대 6.6%의 비트 감소율을 확인하였다.

• Steel and Composite Structures
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• 제24권1호
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• pp.129-140
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• 2017

Structural optimization is one of the popular and active research areas in the field of structural engineering. In the present study, the newly developed moth-flame optimization (MFO) algorithm and its enhanced version termed as enhanced moth-flame optimization (EMFO) are employed to implement the optimization process of planar and 3D steel frame structures with discrete design variables. The main inspiration of this optimizer is the navigation method of moths in nature called transverse orientation. A number of benchmark steel frame optimization problems are solved by the MFO and EMFO algorithms and the results are compared with those of other meta-heuristics. The obtained numerical results indicate that the proposed EMFO algorithm possesses better computational performance compared with other existing meta-heuristics.

• 설비공학논문집
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• 제4권4호
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• pp.289-298
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• 1992

Fouling is "a major unsolved" area in heat transfer research. Currently, fouling researches are performed in every directions-fundamental aspects, modeling and cumulating experimental data. In this study, an attempt was made to extend the knowledge in enhanced tube fouling. The Kern-Seaton fouling model which was originally proposed for smooth tube fouling was extended to repeated rib tubes. Key parameters-mass transfer coefficient and wall shear stress-were modeled for repeated rib tubes. Some critical points related with the enhanced tube fouling-uncertainties in the mass transfer rate, wall shear stress modeling, deformation of roughness shape during fouling-were discussed, and some quantitative evaluations were made.

• Bulletin of the Korean Chemical Society
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• 제28권12호
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• pp.2200-2202
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• 2007

The local field distribution around gold nanosphere-gold plane junction has been studied using the finitedifference time-domain (FDTD) electrodynamics calculation procedure. We find that both the in-plane and out-of-plane polarized excitation produce enhanced field strong enough to explain the observed SERS activities of the junctions. Comparison with a simple dipole-image dipole model shows that the enhanced field primarily originates from the multipole-image multipole interaction, which indicates that the detailed fine-structures of the nanoparticles also play a significant role in the SERS activities as well.

• 설비공학논문집
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• 제28권5호
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• pp.195-201
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• 2016

Enhanced tubes are widely used in air-conditioning and process industries. Structural tubes having three-dimensional roughness are well known to be able to significantly enhance pool boiling heat transfer of refrigerants. In this study, five structural enhanced tubes having different fin density, fin height, and fin gap width were tested using R-134a. Results showed that the heat transfer coefficient was increased with increased fin density. Within test range, the effect of fin height on pool boiling heat transfer coefficient was insignificant. The heat transfer coefficients of the optimum configuration (2047 fpm, 0.21 mm gap width) tube were lower than those of other commercial enhanced tubes. This might be due to the larger fin gap width of the present enhanced tube.

• ETRI Journal
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• 제28권6호
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• pp.826-829
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• 2006

A novel method for optical phase shaped binary transmission (PSBT) generation has been recently reported and experimentally evaluated. An amelioration of the optical signal-to-noise ratio (OSNR) sensitivity of the optical PSBT modulation format is proposed with the application of the concepts of enhanced electrical PSBT signal generation. Enhanced optical PSBT is proposed here as a modulation format producing a 0.7 dB gain in OSNR sensitivity compared to OPSBT, while maintaining a good robustness to group velocity dispersion: 100 ps/nm for enhanced optical PSBT and 120 ps/nm for optical PSBT, compared to 50 ps/nm for standard NRZ signals.

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 2001년도 제6차 학술대회 초록집
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• pp.108-108
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• 2001

Purpose： To correlate the histological differentiation of hepatocellular carcinomas (HCCs) with finding on triple contrast-enhanced MR imaging using gadolinium-chelates, superparamganetic ire oxides (SPIO), and mangafodipir trisodium. Method： Ten patients with proven HCC underwent triple contrast-enhanced MRI befo surgical resection. Subjective ratings of the enhancement pattern and degree were compare with the histological grades determined on surgical specimen. Quantitative measurements signal-to-noise ratio (S/N) of the lesion and the lesion-to-liver contrast-to-noise ratio C/N on the enhanced MR images, and the degree of S/N and C/N changes between the unenhanced and enhanced images were also correlated with the histological grades.