• 한국음향학회지
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• 제20권3호
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• pp.15-23
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• 2001

본 논문에서는 임의의 사람이 발성한 음성을 마치 다른 사람이 발성한 것처럼 들리도록 하는 음성변환 기술에 대하여 설명하고, 화자간의 성도 특성과 여기신호 특성 파라미터 변환을 독립적으로 수행하기 위한 변환방법을 실험한다. 성도 특성 파라미터 변환은 입력되는 음성신호에서 LPC (Linear Predictive Cofficient)켑스트럼을 추출하여 선형다변회귀모델에 적용하여 수행하고, 여기신호 특성 파라미터 변환은 잔차신호를 추출하여 LP-PSOLA (Linear Predictive-Pitch Synchronous Overlap and Add) 합성방식을 이용한 화자간의 평균 피치주기 변환으로 수행된다. 실험결과는 선형다변회귀모델과 LP-PSOLA 합성방식을 이용하여 변환된 음성이 대상화자의 음성에 유사함을 보여준다

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권9호
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• pp.4271-4294
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• 2018

Communication cost is the most important factor in Wireless Sensor Networks (WSNs), as exchanging control keying messages consumes a large amount of energy from the constituent sensor nodes. Time-based Dynamic Keying and En-Route Filtering (TICK) can reduce the communication costs by utilizing local time values of the en-route nodes to generate one-time dynamic keys that are used to encrypt reports in a manner that further avoids the regular keying or re-keying of messages. Although TICK is more energy efficient, it employs no re-encryption operation strategy that cannot determine whether a healthy report might be considered as malicious if the clock drift between the source node and the forwarding node is too large. Secure SOurce-BAsed Loose Synchronization (SOBAS) employs a selective encryption en-route in which fixed nodes are selected to re-encrypt the data. Therefore, the selection of encryption nodes is non-adaptive, and the dynamic network conditions (i.e., The residual energy of en-route nodes, hop count, and false positive rate) are also not focused in SOBAS. We propose an energy efficient selection of re-encryption nodes based on fuzzy logic. Simulation results indicate that the proposed method achieves better energy conservation at the en-route nodes along the path when compared to TICK and SOBAS.

• Bulletin of the Korean Chemical Society
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• 제28권4호
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• pp.533-537
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• 2007

This paper describes the heteroepitaxial growth of single-crystalline 3C-SiC (cubic silicon carbide) thin films on Si (100) wafers by atmospheric pressure chemical vapor deposition (APCVD) at 1350 oC for micro/nanoelectromechanical system (M/NEMS) applications, in which hexamethyldisilane (HMDS, Si2(CH3)6) was used as a safe organosilane single-source precursor. The HMDS flow rate was 0.5 sccm and the H2 carrier gas flow rate was 2.5 slm. The HMDS flow rate was important in obtaing a mirror-like crystalline surface. The growth rate of the 3C-SiC film in this work was 4.3 μm/h. A 3C-SiC epitaxial film grown on the Si (100) substrate was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and Raman scattering, respectively. These results show that the main chemical components of the grown film were single-crystalline 3C-SiC layers. The 3C-SiC film had a very good crystal quality without twins, defects or dislocations, and a very low residual stress.

• 태양에너지
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• 제5권2호
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• pp.46-53
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• 1985

Hydrogenated amorphous silicon solar cells which are fabricated by photo-chemical vapor deposition (photo-CVD) system has been investigated. In the photo-CVD system which consists of three separate reaction chambers, low-pressure mercury lamp has been used as a light source. The main reactant ($Si_2H_6/He$) gases which are premixed with a small amount of mercury vapor in a mercury-vaporizer kept at $50^{\circ}C$ have been used. Using $C_2H_2$ and $SiH_2(CH_3)_2$ as the carbon source, p-type wide band gap a-SiC:H films have been obtained. The result has been found that the undoped layers of the pin/substrate solar cells are influenced by the residual impurities, such as phosphorus and boron during the deposition process. By minimizing the effect of the impurities in the i-layer and optimizing conditions at the p-layer and p/i interface, the energy conversion efficiency of 9.61 % under AM-1 ($100mW/Cm^2$) has been achieved for pin/substrate solar cells illuminated through their p-layers, using the three separate reaction chamber apparatus. It is expected that a-SiC:H solar cells with the energy conversion efficiency over 10% have been fabricated by Photo-CVD method.

• 천문학회보
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• 제43권2호
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• pp.41.1-41.1
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• 2018

We constrain cosmological parameters by combining three different power spectra measured from galaxy clustering, galaxy-galaxy lensing, and cosmic shear using the Deep Lens Survey (DLS). Two lens bins (centered at z~0.27 and 0.54) and two source bins (centered at z~0.64, and 1.1) containing more than one million galaxies are selected to measure the power spectra. We re-calibrate the initial photo-z estimation of the lens bins by matching with SHELS and PRIMUS and confirm its fidelity by measuring a cross-correlation between the bins. We also check the reliability of the lensing signals through the null tests, lens-source flipping and cross shear measurement. Residual systematic errors from photometric redshift and shear calibration uncertainties are marginalized over in the nested sampling during our parameter constraint process. For the flat LCDM model, we determine S_8=sigma_8(Omega_m/0.3)^0.5=0.832+-0.028, which is in great agreement with the Planck data. We also verify that the two independent constraints from the cosmic shear and the galaxy clustering+galaxy-galaxy lensing measurements are consistent with each other. To address baryonic feedback effects on small scales, we marginalize over a baryonic feedback parameter, which we are able to constrain with the DLS data alone and more tightly when combined with Planck data. The constrained value hints at the possibility that the AGN feedback in the current OWLS simulations might not be strong enough.

• Current Optics and Photonics
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• 제5권1호
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• pp.8-15
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• 2021

An elliptical zone plate (EZP) array is important in off-axis optical systems because it provides two advantages. First, the residual beam and the main source are not focused in the same direction and second, the light from the observation plane is not reflected back towards the beam source. However, the fill factor of the previous EZP array was about 76% which was a little low. Hence, this EZP array could not collect the maximum amount of illumination light, which affected the overall optical performance of the lens array. In this study, we propose a new EZP array design with a 97.5% fill factor used in off-axis imaging system for enhancement of brightness and contrast. Then, direct laser lithography was used to fabricate the high fill factor EZP array by moving the XY linear stage of the system in a zigzag motion. The imaging properties of the proposed EZP array were experimentally verified at the focal plane and compared with the previous model.

• 한국환경과학회지
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• 제32권6호
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• pp.419-428
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• 2023

This study estimates the greenhouse gases (GHGs) emissions from energy sector of Changwon city from 2012 to 2020 and scenario analysis of GHGs reductions pathways in the context of the goal of 2030 NDC and 2050 carbon neutral scenario in Korea. As a result, the GHG emissions as a reference year of carbon neutral in 2018 were estimated as 8,872,641 tonCO_2eq accounting for 3,851,786 tonCO_2eq (43.6%) of direct source (scope 1) and 4,975,855 tonCO_2eq (56.4%) of indirect source (scope 2). Especially, among indirect sources as purchased electricity, manufacturing sector emitted the largest GHG accounting for 33.0%(2,915 thousands tonCO_2eq) of the total emissions from all energy sectors, scenario analysis of GHG reductions potential from the energy was analyzed 8,473,614 tonCO_2eq and the residual emissions were 354,027 tonCO_2eq. Purchased electricity and industry sector reducted the largest GHG accounting for 58.7%(4,976 thousands tonCO_2eq) and 42.1%(3,565 thousands tonCO_2eq) of the total emissions from all energy sectors, respectively.

• ETRI Journal
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• 제46권4호
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• pp.604-618
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• 2024

In wireless sensor network (WSN) monitoring systems, redundant data from sluggish environmental changes and overlapping sensing ranges can increase the volume of data sent by nodes, degrade the efficiency of information collection, and lead to the death of sensor nodes. To reduce the energy consumption of sensor nodes and prolong the life of WSNs, this study proposes a dual layer intracluster data fusion scheme based on ring buffer. To reduce redundant data and temporary anomalous data while guaranteeing the temporal coherence of data, the source nodes employ a binarized similarity function and sliding quartile detection based on the ring buffer. Based on the improved support degree function of weighted Pearson distance, the cluster head node performs a weighted fusion on the data received from the source nodes. Experimental results reveal that the scheme proposed in this study has clear advantages in three aspects: the number of remaining nodes, residual energy, and the number of packets transmitted. The data fusion of the proposed scheme is confined to the data fusion of the same attribute environment parameters.

• 한국해양학회지
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• 제30권5호
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• pp.467-479
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• 1995

영일만의 해수유동구조 및 확산특성을 해석하기 위하여 만내 및 만외에서 25시간 연속축류, 표류판 추적, 염료 확산 실험 및 홍수시 형산강 유출수의 항공촬영 등의 체 계적인 해양관측을 실시하였다. 영일만 표층에서 해수유동은 조류보다는 바람과 해류 의 영향을 크게 받고, 중층에서는 해류에 의한 지배적인 영향을 받고 있다. 표층에서 향류는 주로 만의 서쪽해안과 중앙부를 통해 만 내로 유입하였다가 반시계 방향으로 회전하면서 만의 동쪽해안을 따라 만 외로 유출한다. 만의 동쪽해안에서 표층항류는 바람의 영향에 관계없이 만외로 유출하는 흐름인 북-북동방향의 흐름이 발생하고 있으 나, 만의 서쪽해안에서 표층 항류는 바람과 형산강 유출수의 영향을 크게 받는다. 즉, 남-서풍이 탁월하게 발생할 때 나 홍수니 형상강 유출량이 많을 경우 서쪽해안에서 표 층항류는 북-북동방향으로 흐른다. 중층에서 항류는 만의 서쪽해안을 따라 만내로 유 입하였다고 좌선회하면서 만의 동쪽해안을 따라 만외로 유출하는 흐름인 북동방향의 이름이 발생한다. 만의 중앙부에서 실시한 순간점원 방출에 의한 염료운의 확산양상은 표류판의 이동경로와 거의 일치하였으며, Fick의 이론에 의한 염료운의 겉보기 확산계 수는 1.14$\times$$10^4$$cm^2$/s이었다. 그리고, 홍수시 현산강의 유출수는 영일만의 서쪽해안 을 따라 띠모양을 이루면서 만외로 유출 확산되고 있다.

• Journal of Chest Surgery
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• 제47권1호
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• pp.6-12
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• 2014

Background: Although a residual intimal tear may contribute to the dilatation of the descending aorta following surgical repair of acute type I aortic dissection (AD), its causal relationship has not been elucidated by clinical data due to the limited resolution of imaging modalities. Methods: This study enrolled 41 patients (age, $55.2{\pm}11.9$ years) who were evaluated with dual-source computed tomography (CT) imaging of the whole aorta in the setting of the surgical repair of acute type I AD. Logistic regression models were used to determine the predictors of a composite of the aortic aneurysm formation (diameter >55 mm) and rapid aortic expansion (>5 mm/yr). Results: On initial CT, a distal re-entry tear was identified in 9 patients. Two patients failed to achieve proximal tear exclusion by the surgery. Serial follow-up CT evaluations (median, 24.6 months; range, 6.0 to 67.2 months) revealed that 14 patients showed rapid expansion of the descending aorta or aortic aneurysm formation. A multivariate analysis revealed that the residual intimal tear (odds ratio [OR], 4.31; 95% confidence interval [CI], 1.02 to 19.31) and the patent false lumen in the early postoperative setting (OR, 4.64; 95% CI, 0.99 to 43.61) were predictive of the composite endpoint. Conclusion: The presence of a residual intimal tear following surgery for acute type I AD adversely influenced the expansion of the descending aorta.