• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1362-1366
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• 1998

The sterilizing effect of electron beam was compared with that of gamma irradiation for commercial ginseng powders. White and red ginseng powders were contaminated by about $10^5\;CFU/g$ of total bacteria and by $10^3\;CFU$ of coliforms only in white ginseng powder. Data of microbial population for the sterilizing effect of electron beam irradiation showed that no microorganisms were detected in the samples irradiated up to 7.5 kGy for total aerobic bacteria and 2.5 kGy for molds and coliforms. Such doses were effective for controlling the microbial growth in the samples during 4 months of storage at room temperature. Decimal reduction doses $(D_{10}$ value) on the initial bacterial populations were $2.85{\sim}3.75\;kGy$ in electron beam and $2.33{\sim}2.44\;kGy$ in gamma irradiation, which were influenced by the initial microbial loads and the energy applied. Compared with gamma irradiation, electron beam showed a similar result in its sterilizing effect on ginseng powders, suggesting its potential utilization in due time.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1439-1447
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• 1998

Antimicrobial activity of chitosan and chitosan oligosaccharides on the microorganism related to Kimchi was investigated. 5 kinds of chitosan, which have different deacetylation degrees and molecular weights were prepared and its effect on the organoleptic characteristics, pH and titrable acidity of Kimchi in the storage time were examined. C-4 and C-5 chitosan (D.A.:$92{\sim}99%$, M.W.: $16,000{\sim}32,000)$ recorded high score in the texture and showed pH 4.9 and titrable acidity 0.35%, compared with control (pH 4.1, titrarable acidity 0.50 %) evaluated to optimal ripening time. The chitosan oligosaccharides containing relatively large amount of $pentamer{\sim}heptamer$ were chosen from C-4 chitosan hydrolyzates. Antimicrobial activity of C-4 and chitosan oligosaccharides against B. subtilis, B. cereus, Pse. fluorescens, E. coli, Lac. plantarum, Leu. mesenteroides, Lac. brevis, Ent. faecalis and 3 kinds of microflora from Kimchi were examined. The clear zone against microorganism were $9{\sim}20mm$ at 3.0% C-4 chitosan and $8{\sim}24mm$ at 5.0% chitosan oligosaccharides, and MIC of chitosan and chitosan oligosaccharides was shown $0.01{\sim}0.05%$ and $0.05{\sim}0.2%$, respectively. The antimicrobial effect of chitosan and chitosan oligosaccharides was also observed in 3 kinds of total microflora from Kimchi and was most strong in the microflora from the ripening stage of Kimchi, suggesting C-4 chitosan and chitosan oligosaccharides could be applicable to extending shelf-life of Kimchi.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.4
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• pp.78-86
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• 1999

In this paper, a distributed arithmetic digital neural network with learning and testing phase implemented in a body has been studied. The proposed technique is based on the two facts; one is that the weighting coefficients adjusted will be stored in registers without shift, because input values or input patterns are not changed while learning and the other is that the input patterns stored in registers are not changed while testing. The proposed digital neural network is simulated by hardware description language such as VHDL and verified the performance that the neural network was applied to the recognition of seven-segment. To verify proposed neural networks, we compared the learning process of modified perceptron learning algorithm simulated by software with VHDL for 7-segment number recognizer. The results are as follows: There was a little difference in learning time and iteration numbers according to the input pattern, but generally the iteration numbers are 1000 to 10000 and the learning time is 4 to 200$\mu\textrm{s}$. So we knew that the operation of the neural network is learned in the same way with the learning of software simulation, and the proposed neural networks are properly operated. And also the implemented neural network can be built with less amounts of components compared with board system neural network.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.117-124
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• 2017

A Smart Grid is a system that can efficiently use energy by exchanging real-time information in both directions between a consumer and a power supplier using ICT technology on an existing power network. DR(Demand response) is an arrangement in which electricity users can sell the electricity they save to the electricity market when the price of electricity is high or the power system is crisis. In this study, we developed a power meter data transmission device and power IT system that measure the demand information in real-time using a smart meter and transmit it to a cloud server. The power meter data transmission device developed in this study uses alight sensor connected to a Raspberry Pi 3 to measure the number of blinking lamps on the KEPCO meter per unit of power, in order to provide reliable data without any measurement errors with respect to the KEPCO power data. The power measurement data transmission device uses the standard communication protocol, OpenADR 2.0b. The measured data is transmitted to the power IT system, which consists of the VEN, VTN, and calculation program, via the LTE WiFi communication network and stored in its MySQL DB. The developed power measurement data transmission device issues a power supply instruction and performs a peak reduction DR when a power system crisis occurs. The developed power meter data transmission device has the advantage of allowing the user to adjust it every 1 minute, where as the existing smart metering time is fixed at once every 15 minutes.

• Journal of Korea Multimedia Society
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• v.7 no.1
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• pp.12-26
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• 2004

In the past, geographic data is constructed and serviced through independent formats of its own according to each GIS(Geographic Information System). Recently the provision of interoperability in GIS is important to efficiently apply the various geographic data between conventional GIS's. Whereupon OGC(Open GIS Consortium) proposed GML(Geography Markup Language) to offer the interoperability between heterogeneous GISs in distributed environments. The GML is an XML encoding for the transport and storage of geographic information, including both the spatial and non-spatial properties of geographic features. Also, the GML includes Web Map Server Implementation Specification to service the GML documents. Accordingly the prototype to provide the reciprocal interchange of geographic information between conventional GIS's and GML documents is widely studied. In this paper, we propose a mapping method of geographic in formation between spatial database and GML for the prototype to support the interoperability between heterogeneous geographic information. For this method, firstly the scheme of converting geographic in Formation of the conventional spatial database into the GML document according to the GML specification is explained, and secondly the scheme to transform geographic information of GML documents to geographic data of spatial database is showed. Consequently, the proposed method is applicable to the framework for integrated geographic information services based on Web by making an offer the interoperability between already built geographic information of conventional GIS's using a mapping method of geographic information between spatial database and GML.

• Journal of Navigation and Port Research
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• v.33 no.10
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• pp.671-678
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• 2009

Recently, there have been some researches in the equipment fault detection based on shock and vibration information. Most research of them is based on shock and vibration monitoring to determine the equipment fault or not. Different with engine fault detection based on shock and vibration information we focus on detection of engine for boat and system control. First, it use the duplicated-checking method for shock and vibration information to determine the engine fault or not. If there is a fault happened, we use the integral to determine the error engine shock wave width and detect the fault area. On the other hand, we use the engine trend analysis and standard of safety engine to implement the shock and vibration information database. Our simulation results show that the probability of engine fault determination is 98% and the probability of engine fault detection is 72%

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.6
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• pp.493-498
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• 2016

In the present study, graphene oxide based polyurethane foams were manufactured as a part of the development process of mechanically strengthened polyurethane foam insulation material. This material is used in a liquefied natural gas carrier cargo containment system. The temperature of the containment system is $-163^{\circ}C$. First, graphene oxide was synthesized using the Hummers' method, and it was supplemented into polyol-isocyanate reagent by considering a different amount of graphene oxide weight percent. Then, a bulk form of graphene-oxide-polyurethane foam was manufactured. In order to investigate the cell stability of the graphene-oxide-polyurethane foam, its microstructural morphology was observed, and the effect of graphene oxide on microstructure of the polyurethane foam was investigated. In addition, the compressive strength of graphene-oxide-polyurethane foam was measured at ambient and cryogenic temperatures. The cryogenic tests were conducted in a cryogenic chamber equipped with universal testing machine to investigate mechanical and failure characteristics of the graphene-oxide-polyurethane foam. The results revealed that the additions of graphene oxide enhanced the mechanical characteristics of polyurethane foam. However, cell stability and mechanical strength of graphene-oxide-polyurethane foam decreased as the weight percent of graphene oxide was increased.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.3
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• pp.197-201
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• 2017

Most fishing vessels use an ice cooling system to manage and store captured fish. However, it is difficult to maintain an adequate temperature and salt concentration as well as operating time limitations in ice cooling systems. The purpose of this study is to investigate the heat transfer characteristics of flooded-type evaporators for a seawater cooling system to maintain proper seawater temperature in a fish tank. Experiments were conducted to investigate the heat transfer characteristics by changing the seawater temperature, flow rate, and saturation temperature of the refrigerant. It was confirmed that the heat transfer coefficient of an aluminum-brass tube was approximately 10% higher than that of a copper-nickel tube at the same heat flux. Furthermore, it was confirmed that applying the aluminum-brass tube to the heat transfer tube of a seawater heat exchanger was effective in terms of heat transfer. A comparison of the overall heat transfer coefficient of a single-tube heat exchanger and the flooded-type multi-tube heat exchanger for an 18-kW cooling system showed that the heat transfer coefficient of the single-tube heat exchanger was 25% higher under the same conditions. These results are considered to be important data for designing a flooded-type multi-tube heat exchanger.

• The KIPS Transactions:PartD
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• v.13D no.4 s.107
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• pp.549-556
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• 2006

In this paper, we propose a system for generating skeleton programs for directly transforming an XML document to another document, whose structure is defined in the target DTD with GUI environment. With the generated code, the users can easily update or insert their own codes into the program so that they can convert the document as the way that they want and can be connected with other classes or library files. Since most of the currently available code generation systems or methods for transforming XML documents use XSLT or XQuery, it is very difficult or impossible for users to manipulate the source code for further updates or refinements. As the generated code in this paper reveals the code along the XPaths of the target DTD, the result code is quite readable. The code generating procedure is simple; once the user maps the related elements represented as trees in the GUI interface, the source document is transformed into the target document and its corresponding Java source program is generated, where DTD is given or extracted from XML documents automatically by parsing it. The mapping is classified 1:1, 1:N, and N:1, according to the structure and semantics of elements of the DTD. The functions for changing the structure of elements designated by the user are amalgamated into the metadata interface. A real world example of transforming articles written in XML file into a bibliographical XML document is shown with the transformed result and its code.

• Journal of the Korean Electrochemical Society
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• v.11 no.1
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• pp.42-46
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• 2008

Even though fuel cell have high efficiency when pure hydrogen from gas tank is used as a fuel source, it is more beneficial to generate hydrogen from city gas (mainly methane) in residential application such as domestic or office environments. Thus hydrogen is generated by reforming process using hydrocarbon. Unfortunately, the reforming process for hydrogen production is accompanied with unavoidable impurities. Impurities such as CO, $CO_2$, $H_2S$, $NH_3$, $CH_4$, and $CH_4$ in hydrogen could cause negative effects on fuel cell performance. Those effects are kinetic losses due to poisoning of the electrode catalysts, ohmic losses due to proton conductivity reduction including membrane and catalyst ionomer layers, and mass transport losses due to degrading catalyst layer structure and hydrophobic property. Hydrogen produced from reformer eventually contains around 73% of $H_2$, 20% or less of $CO_2$, 5.8% of less of $N_2$, or 2% less of $CH_4$, and 10ppm or less of CO. This study is aimed at investigating the effect of carbon dioxide on fuel cell performance. The performance of PEM fuel cell was investigated using current vs. potential experiment, long run(10 hr) test, and electrochemical impedance measurement when the concentrations of carbon dioxide were 10%, 20% and 30%. Also, the concentration of impurity supplied to the fuel cell was verified by gas chromatography(GC).