• Journal of IKEEE
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• v.24 no.4
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• pp.1122-1128
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• 2020

Bandwidth Extension refers to restoring and expanding a narrow band signal(NB) that is damaged or damaged in the encoding and decoding process due to the lack of channel capacity or the characteristics of the codec installed in the mobile communication device. It means converting to a wideband signal(WB). Bandwidth extension research mainly focuses on voice signals and converts high bands into frequency domains, such as SBR (Spectral Band Replication) and IGF (Intelligent Gap Filling), and restores disappeared or damaged high bands based on complex feature extraction processes. In this paper, we propose a model that outputs an bandwidth extended signal based on an autoencoder among deep learning models, using the residual connection of one-dimensional convolutional neural networks (CNN), the bandwidth is extended by inputting a time domain signal of a certain length without complicated pre-processing. In addition, it was confirmed that the damaged high band can be restored even by training on a dataset containing various types of sound sources including music that is not limited to the speech.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.3
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• pp.17-28
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• 2024

In this study, the capacity of the tunnel and the general section was calculated and compared using the VDS detector data, and the decrease rate in capacity of the tunnel section was analyzed by tunnel type. To compare the capacity of the tunnel and the general section, the Product Limit Method (PLM) was applied to the VDS detector data. As a result of comparing the capacity of the tunnel and general section, the capacity of the tunnel section decreased by about 6.5% compared to the general section. To classify the tunnel type, the tunnel extension and the number of lanes were used as variables, and there was a difference in the decrease rate of capacity by tunnel group classified by each criterion.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.7
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• pp.1013-1018
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• 2014

This paper described the development of equalizing spacer for minimization of voltage drop according to DC feeder extension. Power consumption is increased as shorter interval of train driving time and transportation capacity increase in urban subway. Therefore we investigated voltage drop of catenary at a point in case of traction driving of a train in parallel to the DC power supply system. Based on it's result, equalizing spacer is designed and fabrication to minimize the voltage drop in accordance with the power supply line arranged in three rows, and then its performance was confirmed that the stress distribution of main body and the distributed load are satisfied through the body structure modeling.

• Journal of Agricultural Extension & Community Development
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• v.22 no.4
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• pp.455-464
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• 2015

The purposes of this study are to explain and identify the frame of structural relations of learning orientation, self-efficacy, learning transfer and job performance of farmers who participated in the strong and small farms education. This is an experimental research with the data collected from 495 farmers who have taken the farm education. Based on the collected data, the study conducted a structural equation modeling(SEM) to confirm the validity and analyze the structural relations of the suggested model. Using measured and latent variables drew from the analyses, the study set a structural equation model and tested the model by analysis of the structural equation modeling with AMOS 18.0. The results found from the empirical analysis can be summarized as follows. 1) Learning orientation and self-efficacy positively influenced job performance through learning transfer. 2) The hypothesis that learning orientation would have direct impact on job performance was not supported. 3) The strong and small farms education is useful to expand learning transfer and to enhance job performance. So, government policy support has to reinforce learning support on farmers in order to achieve high performance of learning and job management through farm educations.

• Korean Journal of Plant Resources
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• v.35 no.6
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• pp.820-824
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• 2022

Ecologically sustainable means of development is the point to support environmental homeostasis. One of our roles is to find bio-degradable resources that can be substituted for petroleum-based products to effectively abide by the natural viability. To counter the issues of deforestation and preserve biodiversity, it is necessary to produce a non-wood crop that can fulfill the requirement for raw material from which several products can be produced. Kenaf (Hibiscus cannabinus), a member of the family Malvaceae, is showing sufficient potentiality along this road-map. Due to its rich fiber content, it has been used extensively in various fields for long, probably as early as 4,000 BC. At present, kenaf has been used as provider of paper, plastics, fiber glass, biofuel, activated carbon and epoxy composite. This obviously catch one's attention towards its capability to replace petroleum-based products as a whole. Moreover, the plant shows considerable relevance in decreasing pollutants by virtue of its enormous absorption capacity. These multiple applications of kenaf justify its credibility to be the best resource for the better world. The paper presents an overview on its numerous uses reported in the literature that we have investigated and its great potential as a valuable multipurpose crop.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.443-445
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• 2001

As the new large buildings are continuously being built with the advanced technology and skills, an adequate size of electric room needs to be obtained so that engineers establish an efficient and reliable system in the electric room. Considering the current capacity, its expansion and its connecting system, the final size of it should be determined in order to bring an effective use of the building. Usually the extension of electricity capacity is on the increase after construction and it comes from the lack of scientific evaluation on the electric room. Later when the expansion of computer and important electric equipment that needs much capacity is impossible, it will cause a great deal of damage to the renting business of the building as well as becomes the unstable factors of the whole system. Therefore, it is important to have the exact method of calculating the effective size of electric room, the heart of the building, especially when the value of land price is very high. In addition, it should be calculated in an accurate way due to the diversification of the system and the compact size of the electricity equipment. However, the research on this area and the comparison and evaluation of the size after construction have not been made enough and the results of them have not been applied when calculating a new size of electric room. Accordingly, this study examines three methods prescribed in the standards of electricity installation technology through case analysis and suggests substantial data by system, capacity, and purpose.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.9
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• pp.749-755
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• 2002

In order to develop a multi-type heat pump system with two indoor units of non-uniform capacities, the optimum refrigerant circuit was developed using capillary tubes. The refrigerant circuit was composed of four main parts, a heating circuit, a cooling circuit, a by-pass circuit and a balance circuit. The system characteristics of multi-type heat pump was investigated through the rating test and the reliability test, using the multi-type psy-chrometric calorimeter. The results of the rating test showed that the capacity of the multi-type heat pump was about 93% of the design value. In particular, the capacity of cooling single mode was about 13% higher than the design value, and the capacity of heating multi mode was about 5% higher than the design value. The reliability of the multi-type heat pump was verified by various reliability tests (overload, extension tube, freeze up, under/over charging, sweat, flood back). The optimal amount of refrigerant charge and compressor capacity were determined from the present work.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.102-102
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• 2019

Soybean curd residue (SCR), known as a major waste product of soybean processing, is the water-insoluble fraction which is removed by filtration during soymilk production. For these reasons, SCR was usually considered as food waste. SCR might have a good potential as a functional food material, value-added processing and utilization. SCR contains high-quality protein and consists of a good source of nutrients, including protein, oil, dietary fiber, minerals, along with un-specified monosaccharides and oligosaccharides. Also, SCR might be a potential source of low cost protein for human consumption. However, SCR could be a source of bacterial contamination when during food processing. This study was aimed to investigate antibacterial capacity of natural product through detecting relationship between SCR and microbial. We isolated five bacterial strains from SCR and elucidated antibacterial activity of nature medicines to extend storage capacity of food made with SCR. Thus, the extract which showed antibacterial effects in Corynebacterium calloonae and Raoultella amithinolytica is a combination of seven kinds of extracts: Glycyrrhiza uralensis, Cudrania tricuspidata, Salvia miltiorrhiza Bunge, blueberry, Acorus gramineus, Ginkgo biloba L., Camellia sinensis. This study suggested that antibacterial activities of natural medicines could be used for extension of storage capacity in SCR-contained food.

• Journal of Korean Association for Spatial Structures
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• v.24 no.1
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• pp.29-36
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• 2024

The paper presents the experimental investigation of RC beams retrofitted with Textile Reinforced Mortar (TRM), featuring enhanced bond capacity. Anchoring systems, including an extension of retrofitting length and the use of chemical anchors, are newly employed to improve the structural performance of the RC beam retrofitted with TRM. For the experimental investigation, a total of seven shear-critical RC beams, with and without stirrups, were designed and constructed. The structural behaviors of specimens retrofitted with the proposed TRM methods were compared to those of non-retrofitted specimens or specimens strengthened with conventional TRM methods. Crack pattern, force-displacement relationship, and absorbed energy were evaluated for each specimen. The experimental results indicate a significant improvement in the shear capacity of the RC beam with the proposed retrofitting method. Therefore, it is concluded that the application of an extended retrofitting length and chemical anchors to the TRM retrofitting method can effectively enhance the bond capacity of TRM, thereby improving the shear performance of RC beams.

• Fisheries and Aquatic Sciences
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• v.27 no.3
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• pp.195-205
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• 2024

Amphipoda is a benthic fauna occupying aquatic environments that can be used as a live feed for mud crabs. The abundance of amphipods in the water is thought to impact the preying capacity of crablets, which in turn will affect their growth performance. This study aims to determine the preying capacity of the crablet stage of Scylla tranquebarica exposed at different densities (20, 30, and 40 amphipods / 0.5 L) of amphipod, Grandidierella megnae. The preying capacity was estimated by counting the number of amphipods ingested by an individual crablet during the 60-day rearing period. The main parameters measured were daily consumption rate (DCR), Cumulative molting (CM), Feed conversion ratio (FCR), and the specific growth rate of weight (SGR-W). The results showed that the DCR and FCR were not affected by amphipod densities but the higher the amphipod density the higher the SGR-W and CM. Based on this study, 30 amphipods / 0.5 L is recommended as the optimal density to optimize the DCR and improve the growth performance of crablets. It is also proposed that surplus live feed will potentially reduce the cannibalism rate of crablets during weaning. However, more research needs to be carried out to elucidate the benefits of crablet-feeding amphipods in communal systems.