• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.5
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• pp.623-629
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• 2004

In this paper, a Efficient method for the mixed image separation is presented using independent component analysis and the new fast expectation-maximization(EM) algorithm. In general, the independent component analysis (ICA) is one of the widely used statistical signal processing scheme in various applications. However, it has been known that ICA does not establish good performance in source separation by itself. So, Innovation process which is one of the methods that were employed in image separation using ICA, which produces improved the mixed image separation. Unfortunately, the innovation process needs long processing time compared with ICA or EM. Thus, in order to overcome this limitation, we proposed new method which combined ICA with the New fast EM algorithm instead of using the innovation process. Proposed method improves the performance and reduces the total processing time for the Image separation. We compared our proposed method with ICA combined with innovation process. The experimental results show the effectiveness of the proposed method by applying it to image separation problems.

• Journal of IKEEE
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• v.13 no.3
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• pp.55-61
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• 2009

The heat transfer analysis applying finite element method has been carried out. Particularly, the convection boundary condition associated with the mixed boundary condition is numerically formulated by the Galerkin method analogous to the magnetic field problem. Also, the coupled electromagnet-thermal field analysis by the proposed heat transfer coefficient computation algorithm is executed to enhance the accuracy of solutions. Finally, the validity of the proposed results is verified by comparison with the measured ones.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.3
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• pp.271-276
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• 2016

Cooperative networks enhance the overall communication performance by combining signals from relay nodes and direct signal. In this paper, we analyze the performance of cooperative communication systems which use mixed relaying protocols. By assuming several relay nodes exist between the source node and destination node, we consider the systems use not a single relaying protocol but both decode-and-forward and amplify-and-forward protocols randomly. We analyze the effect of each relying protocol for the overall system performance, and also consider the performance depending on the relay location. Differential modulation scheme which demodulates signal without channel state information is adopted where it can be applicable fast varying channel such as railway environments.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.59-65
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• 2008

Six total mixed rations (TMR) containing 0, 4, 6, 8, 10, 12% tannin (TMR I-VI), using Accacia nilotica pods as a source of tannin, were used to study the effect of Acacia tannin on in vitro nutrient digestibility and gas production in goats. This study also investigated the degraded products of Acacia nilotica tannin in goat rumen liquor. Degraded products of tannins were identified using high performance liquid chromatography (HPLC) at different hours of incubation. In vitro digestibility of dry matter (IVDMD) and organic matter (IVOMD) were similar in TMR II, and I, but declined (p<0.05) thereafter to a stable pattern until the concentration of tannin was raised to 10%. In vitro crude protein digestibility (IVCPD) decreased (p<0.05) with increased levels of tannins in the total mixed rations. Crude protein digestibility was much more affected than digestibility of dry matter and organic matter. In vitro gas production (IVGP) was also reduced (p<0.05) with increased levels of tannins in the TMR during the first 24 h of incubation and tended to increase (p>0.05) during 24-48 h of incubation. Gallic acid, phloroglucinol, resorcinol and catechin were identified at different hours of incubation. Phloroglucinol and catechin were the major end products of tannin degradation while gallate and resorcinol were produced in traces. It is inferred that in vitro nutrient digestibility was reduced by metabolites of Acacia nilotica tannins and ruminal microbes of goat were capable of withstanding up to 4% tannin of Acacia nilotica pods in the TMR without affecting in vitro nutrient digestibility.

• Journal of Information Technology Services
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• v.15 no.1
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• pp.39-66
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• 2016

There is growing evidence that professional work is changing as a result of the application of information technology (IT). However, the impact of information technology on professional work has produced mixed results. Our paper considers the source of these mixed results through a greater analytical attention paid to the nature of professional work. Defined as work involving expertise expressed through abstract and formalized knowledge as well as extensive working knowledge, the professional work logic assumes the greatest autonomy and discretion for workers in collectively controlling work characteristics-division of labor and its permanence, control over education, and control over new entrants and the monitoring and disciplining of existing members. The impact of IT on professional work will be difficult to control and predict without considering the assumptions and tensions within and across the three major types of work logics (Professional, Market and Bureaucratic). Using healthcare as an example, the paper provides various propositions for researching the initiation and effects of ICT design through these three work logics. These propositions illustrate the active role that IS researchers can take in researching an important economic and work-related topic, professional work, and in understanding how ICT affects work-related expertise.

• Journal of Microbiology and Biotechnology
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• v.20 no.5
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• pp.853-861
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• 2010

High substrate costs decrease the profitability of polyhydroxyalkanoates (PHAs) production, and thus low-cost carbon substrates coming from agricultural and industrial residuals are tested for the production of these biopolymers. Among them, crude glycerol, formed as a by-product during biodiesel production, seems to be the most promising source of carbon. The object of this study was to characterize the mixed population responsible for the conversion of crude glycerol into PHAs by cultivation-dependent and -independent methods. Enrichment of the microbial community was monitored by applying the Ribosomal Intergenic Spacer Analysis (RISA), and the identification of community members was based on 16S rRNA gene sequencing of cultivable species. Molecular analysis revealed that mixed populations consisted of microorganisms affiliated with four bacterial lineages: ${\alpha}$, ${\gamma}$-Proteobacteria, Actinobacteria, and Bacteroides. Among these, three Pseudomonas strains and Rhodobacter sp. possessed genes coding for polyhydroxyalkanoates synthase. Comparative analysis revealed that most of the microorganisms detected by direct molecular analysis were obtained by the traditional culturing method.

• KSBB Journal
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• v.26 no.5
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• pp.365-373
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• 2011

Effective Microorganisms (EM), a fermented medium developed by Professor Higa at the University of the Ryukyus, is a mixed culture containing dozens of microorganisms which are beneficial to nature including people, animals, plants and many microbial species in environment. EM is known to contain more than 80 kinds of anaerobic or aerobic microbes including photosynthetic bacteria, lactic acid bacteria, yeast, actinomycetes, fungi and so on, with yeast, lactic acid bacteria and photosynthetic bacteria as the main species of EM. Antioxidant effect generated by the concert of complex coexistence and coprosperity among these microbes is considered to be the main source of EM benefits. Currently, EM is earning an increasing attention with applications in agriculture, forestry, animal husbandry, fisheries, environment and medicine among others. At the same time, however, a quantitative interpretation of EM system based on a mixed culture model needs efforts from biochemical engineers for efficient production and further promotion of EM. In this paper, we describe the functions of major microbes in EM and current researches and applications of EM in agriculture, forestry, animal husbandry, fisheries, environment and medicine.

• Journal of Electrical Engineering and Technology
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• v.7 no.2
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• pp.236-239
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• 2012

In this paper, we study the transient characteristics of 4H-SiC DMOSFETs with different interface charges to improve the turn-on rising time. A physics-based two-dimensional mixed device and circuit simulator was used to understand the relationship between the switching characteristics and the physical device structures. As the $SiO_2$/SiC interface charge increases, the current density is reduced and the switching time is increased, which is due primarily to the lowered channel mobility. The result of the switching performance is shown as a function of the gate-to-source capacitance and the channel resistance. The results show that the switching performance of the 4H-SiC DMOSFET is sensitive to the channel resistance that is affected by the interface charge variations, which suggests that it is essential to reduce the interface charge densities in order to improve the switching speed in 4H-SiC DMOSFETs.

• Nuclear Engineering and Technology
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• v.52 no.1
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• pp.178-184
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• 2020

The traditional methods for radiation shield design always only focus on either the structure or the components of the shields rather than both of them at the same time, which largely affects the shielding performance of the facilities, so in this paper, a novel method for designing the structure and components of shields simultaneously is put forward to enhance the shielding ability. The method is developed by using the genetic algorithm (GA) and the MCNP software. In the research, six types of shielding materials with different combinations of elements such as polyethylene (PE), lead (Pb) and Boron compounds are applied to the radiation shield design, and the performance of each material is analyzed and compared. Then two typical materials are selected based on the experiment result of the six samples, which are later verified by the Compact Accelerator Neutron Source (CANS) facility. By using this method, the optimal result can be reached rapidly, and since the design progress is semi-automatic for most procedures are completed by computer, the method saves time and improves accuracy.

• Journal of Hydrogen and New Energy
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• v.30 no.2
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• pp.111-118
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• 2019

Greenhouse gas emissions have a profound effect on global warming. Various environmental regulations have been introduced to reduce the emissions. The largest amount of greenhouse gases, including carbon dioxide, is produced in the steel industry. To decrease carbon dioxide emission, hydrogen-based iron oxide reduction, which can replace carbon-based reduction has received a great attention. Iron production generates various by-product gases, such as cokes oven gas (COG), blast furnace gas (BFG), and Linz-Donawitz gas (LDG). In particular, COG, due to its high concentrations of hydrogen and methane, can be reformed to become a major source of hydrogen for reducing iron oxide. Nevertheless, continuous COG cannot be supplied under actual operation condition of steel industry. To solve this problem, this study proposed to use two alternative COG-based fuel mixtures; one with natural gas and the other with biogas. Reforming study on two types of mixed gas were carried out to evaluate catalyst performance under a variety of operating conditions. In addition, methane conversion and product composition were investigated both theoretically and experimentally.