• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.189-189
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• 2012

Lead sulfide (PbS) nanocrystal quantum dots (NQDs) are promising materials for various optoelectronic devices, especially solar cells, because of their tunability of the optical band-gap controlled by adjusting the diameter of NQDs. PbS is a IV-VI semiconductor enabling infrared-absorption and it can be synthesized using solution process methods. A wide choice of the diameter of PbS NQDs is also a benefit to achieve the quantum confinement regime due to its large Bohr exciton radius (20 nm). To exploit these desirable properties, many research groups have intensively studied to apply for the photovoltaic devices. There are several essential requirements to fabricate the efficient NQDs-based solar cell. First of all, highly confined PbS QDs should be synthesized resulting in a narrow peak with a small full width-half maximum value at the first exciton transition observed in UV-Vis absorbance and photoluminescence spectra. In other words, the size-uniformity of NQDs ought to secure under 5%. Second, PbS NQDs should be assembled carefully in order to enhance the electronic coupling between adjacent NQDs by controlling the inter-QDs distance. Finally, appropriate structure for the photovoltaic device is the key issue to extract the photo-generated carriers from light-absorbing layer in solar cell. In this step, workfunction and Fermi energy difference could be precisely considered for Schottky and hetero junction device, respectively. In this presentation, we introduce the strategy to obtain high performance solar cell fabricated using PbS NQDs below the size of the Bohr radius. The PbS NQDs with various diameters were synthesized using methods established by Hines with a few modifications. PbS NQDs solids were assembled using layer-by-layer spin-coating method. Subsequent ligand-exchange was carried out using 1,2-ethanedithiol (EDT) to reduce inter-NQDs distance. Finally, Schottky junction solar cells were fabricated on ITO-coated glass and 150 nm-thick Al was deposited on the top of PbS NQDs solids as a top electrode using thermal evaporation technique. To evaluate the solar cell performance, current-voltage (I-V) measurement were performed under AM 1.5G solar spectrum at 1 sun intensity. As a result, we could achieve the power conversion efficiency of 3.33% at Schottky junction solar cell. This result indicates that high performance solar cell is successfully fabricated by optimizing the all steps as mentioned above in this work.

• Korean Journal of Poultry Science
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• v.40 no.4
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• pp.379-388
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• 2013

Avian paramyxovirus (APMV) type 4 and 6 were isolated during an avian influenza (AI) surveillance program of wild birds. This study also conducted experimental infection of wild-bird-origin APMV type 4 and 6 in specific pathogen free (SPF) chickens to study pathogenicity and transmission within domestic flocks. In addition, serological prevalence data of APMV type 4 and 6 in domestic fowls was conducted with chicken sera collected from 2007 to 2009 in order to understand infection status. The results of the animal experiment showed that APMV type 4 and 6 had the ability to infect chickens with sero-conversion and to transmit the virus from infected birds to contacted birds, but showed low pathogenicity. Serological tests revealed that APMV type 4 was widespread in the poultry industry, especially in layer flocks, but the positive rate for APMV type 6 was very low. This study concluded that wild bird-origin APMV type 4 and 6 could infect the chickens by inter-species transmission and the seroprevalence of APMV type 4 was quite high in Korean poultry. However, since almost all the chicken flocks had a high level of antibody titer against APMV type 1, there was possibility of cross reaction between APMV type 1 and 4, which made the interpretations more complicated. In order to understand infection status in the natural environment, additional study is necessary regarding the seroprevalence of APMV type 4 and 6 in the wild bird population.

• Analytical Science and Technology
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• v.24 no.2
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• pp.142-149
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• 2011

This study was conducted to define metabolite of the resveratrol by gas chromatography- time-offlight mass spectrometric detection. From these results, we suppose that the structure of metabolite is the result of reduction of double-bond attached by two-phenyl groups. Also, validity of method for determining metabolite of resveratrol and endogenous steroids was tested. The recoveries ranged from 96.47 to 114.74%, and intraand inter-day precision ranged 11.40 - 10.87% and 1.10 - 10.93%, accuracy ranged 80.03 - 119.92% and 80.02 - 119.56%, respectively. Resveratrol and endogenous steroids had correlation coefficients above or equal to 0.996. The method was successfully validated for the determination of resveratrol and endogenous steroids. Urinary samples from volunteers dosed resveratrol were analyzed to confirm a correlation resveratrol and its metabolite. From these results, the highest level of resveratrol and its metabolite was excreted in 10 - 15 hr more slowly than common drug, and conversion rate of metabolite was higher in woman than that in man. In addition, endogenous steroids were shown same the highest level of 10 - 15 hr. For estrone and estradiol, sensitivity was relatively higher in female than in man. And there were no significant changes of excretion patterns in the other endogenous steroids. Thus, we assumed that activation of resveratrol has impact on woman than man.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.11
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• pp.801-807
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• 2022

In this paper, we propose an ultra compact S-Band PCM/FM telemetry transmitter. The equipment is compact, so it can be applied to a limited space and capable of stable data transmission was designed and manufactured even with specifications set differently for each operating environment and system. RF direct conversion structure is used for the miniaturization of equipment, an RF transmission board, Power distribution board, and a signal processing board were implemented on a single PCB, so that the function of the transmitter could be performed with a minimum device. According to the target specification, variable output of 1~10W and variable data rate of 390kbps~12.5Mbps is possible in S-Band(2,200~2,400MHz) without degradation of performance. To verify the performance of the equipment, the RF performance test and BER measurement test were performed after the equipment was manufactured. It was confirmed that the OBW, null-to-null bandwidth, 1st IMD, Spurious emission, Phase noise specification of the PCM/FM modulated signal which is presented by the IRIG standard were satisfied, and we can confirm the data received using the transmitter inspection equipment were transmitted normally without distortion.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.2
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• pp.138-148
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• 2001

Digital Video (DV) coding standards for digital video cassette recorder are based mainly on DCT and variable length coding. DV has low hardware complexity but high compressed bit rate of about 26 Mb/s. Thus, it is necessary to encode video with low complex video coding at the studios and then transcode compressed video into MPEG-2 for video-on-demand system. Because these coding methods exploit DCT, transcoding in the DCT domain can reduce computational complexity by excluding duplicated procedures. In transcoding DV into MPEC-2 intra coding, multiplying matrix by transformed data is used for 4:1:1-to-4:2:2 chroma format conversion and the conversion from 2-4-8 to 8-8 DCT mode, and therefore enables parallel processing. Variance of sub block for MPEG-2 rate control is computed completely in the DCT domain. These are verified through experiments. We estimate motion hierarchically using DCT coefficients for transcoding into MPEG-2 inter coding. First, we estimate motion of a macro block (MB) only with 4 DC values of 4 sub blocks and then estimate motion with 16-point MB using IDCT of 2$\times$2 low frequencies in each sub block, and finish estimation at a sub pixel as the fifth step. ME with overlapped search range shows better PSNR performance than ME without overlapping.

• Journal of Broadcast Engineering
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• v.20 no.5
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• pp.687-696
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• 2015

JCT-VC (Joint Collaborative Team on Video Coding) continues developing HEVC/Screen Content Coding (HEVC/SCC) as an extension for efficiently coding screen content videos, including computer animations, graphics, and electrical documents, based on HEVC/Range extension (HEVC/RExt.). Color space conversion from RGB space being captured from CCD sensors is popular in natural video coding. However, the conversion is often undesired for screen contents because of a significant loss in perceptual quality. Therefore, several coding tools including cross-component prediction (CCP) and in-loop adaptive color space transform (ACST) have been developed for an efficient screen content video coding in order to reduce the redundancies between color spaces while maintaining the original color space. In this paper, we review the two coding tools, i.e., CCP and ACST exploiting the correlation in the RGB color space and conduct the performance analysis of the coding tools. In our simulation results, CCP and ACST provide 11.7% BD-rate saving and 16.4% BD-rate saving, respectively, while the two coding tools provide 18.2% BD-rate saving in total. Following this idea, if the two coding tools are exclusively selected, we provide 93% encoding measurement time with a 0.3% coding loss.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.4
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• pp.207-216
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• 2014

Total organic carbon (TOC) is an important indicator used as an direct biological index in the research field of the marine carbon cycle. It is possible to produce the sufficient TOC estimation data by using the Chemical Oxygen Demand(COD) data because the available TOC data is relatively poor than the COD data. The outlier detection and treatment (removal) should be carried out reasonably and objectively because the equation for a COD-TOC conversion is directly affected the TOC estimation. In this study, it aims to suggest the optimal regression model using the available salinity, COD, and TOC data observed in the Korean coastal zone. The optimal regression model is selected by the comparison and analysis on the changes of data numbers before and after removal, variation coefficients and root mean square (RMS) error of the diverse detection methods of the outlier and influential observations. According to research result, it is shown that a diagnostic case combining SIQR (Semi - Inter-Quartile Range) boxplot and Cook's distance method is most suitable for the outlier detection. The optimal regression function is estimated as the TOC(mg/L) = $0.44{\cdot}COD(mg/L)+1.53$, then determination coefficient is showed a value of 0.47 and RMS error is 0.85 mg/L. The RMS error and the variation coefficients of the leverage values are greatly reduced to the 31% and 80% of the value before the outlier removal condition. The method suggested in this study can provide more appropriate regression curve because the excessive impacts of the outlier frequently included in the COD and TOC monitoring data is removed.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.825-834
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• 2023

The demands of people who purchase fashion products on Internet shopping are gradually increasing, and attempts are being made to provide user-friendly images with 3D contents and web 3D software instead of pictures and videos of products provided. As a reason for this issue, which has emerged as the most important aspect in the fashion web shopping industry, complaints that the product is different when the product is received and the image at the time of purchase has been heightened. As a way to solve this problem, various image processing technologies have been introduced, but there is a limit to the quality of 2D images. In this study, we proposed an automatic conversion technology that converts 2D images into 3D and grafts them to web 3D technology that allows customers to identify products in various locations and reduces the cost and calculation time required for conversion. We developed a system that shoots a mannequin by placing it on a rotating turntable using only 8 cameras. In order to extract only the clothing part from the image taken by this system, markers are removed using U-net, and an algorithm that extracts only the clothing area by identifying the color feature information of the background area and mannequin area is proposed. Using this algorithm, the time taken to extract only the clothes area after taking an image is 2.25 seconds per image, and it takes a total of 144 seconds (2 minutes and 4 seconds) when taking 64 images of one piece of clothing. It can extract 3D objects with very good performance compared to the system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4290-4300
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• 2014

The previous HL7 interface should be developed as a separate package or conversion module for each version to process HL7 messages from different versions. This study designed and developed an HL7 parser compatible among different versions based on the requirements of compatibility defined in HL7 V2.5. According to the structure of the parser, the inheritance concept in object-oriented programming was adopted so that the class object of the HL7 message from the lower version could be inherited to the class object of the upper version. Therefore, every version's HL7 messages could be processed using only the upper class' object regardless of the version. To evaluate the compatibility of the developed parser, 700 data sets about inpatients with rheumatoid arthritis were used. The 700 cases underwent the compatibility test successfully. In the near future, further research on the Inter-compatibility HL7 parser is planned.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.6
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• pp.755-764
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• 2017

The current review seeks to highlight the concerns that have been raised on pre-slaughter stress, contributing factors and its consequent effects on cattle behavioural responses and the quality of beef; inter-linking the activities involved from birth to slaughter. Such information is crucial in light of the consumer concerns on overall animal welfare, quality of meat and food security. Slaughter animals are exposed to different conditions during production and transportation to abattoirs on a daily basis. However; the majority of studies that have been done previously singled out different environments in the meat production chain, while conclusions have been made that the welfare of slaughter animals and the quality of meat harvested from them is dependent on the whole chain. Behaviour is a critical component used to evaluate the animals' wellbeing and it has been reported to have an effect on product quality. Apart from the influence of on-farm, transportation and abattoir conditions, the genetic background of the animal also affects how it perceives and responds to certain encounters. Stress activates the animals' hypothalamic-pituitary-adrenal activity, triggering release of various stress hormones such as catecholamines and cortisol, thus glycogen depletion prior slaughter, elevated ultimate pH and poor muscle-meat conversion. Pre-slaughter stress sometimes results to cattle attaining bruises, resulting to the affected parts of the carcass being trimmed and condemned for human consumption, downgrading of the carcass and thus profit losses.