• Transactions of the Korean Society of Mechanical Engineers B
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• 제34권4호
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• pp.417-422
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• 2010

Low temperature diesel combustion was achieved via a combination of late injection timing ($8.5^{\circ}$ CA BTDC to $0.5^{\circ}$ CA BTDC) and heavy exhaust gas recirculation (37% to 48%) with ultra low sulfur Swedish diesel fuel in a 1.7L common rail direct injection diesel engine. When injection timing is retarded at a certain exhaust gas recirculation rate, the particulate matter and nitrogen oxides decease simultaneously, while the hydrocarbon and carbon monoxide increase. Hydrocarbon speciation by gas chromatography using a flame ionization detector reveals that the ratio of partially burned hydrocarbon, i.e., mainly alkenes increase as the injection timing is retarded and exhaust gas recirculation is increased. The two most abundant hydrocarbon species are ethene which is a representative species of partially burned hydrocarbons, and n-undecane, which is a representative species of unburned hydrocarbons. They may be used as surrogate hydrocarbon species for performing a bench flow reactor test for catalyst development.

• Journal of the Korean Society for information Management
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• 제29권4호
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• pp.123-142
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• 2012

To develop an intelligent search engine to help users retrieve information effectively, various methods, such as Semantic Web, have been used, An effective retrieval method of such methods uses ontology technology. In this paper, we built National R&D ontology after analyzing National R&D Information in NTIS and then implemented National R&D Knowledge Map to represent and retrieve information of the relationship between object and subject (project, human information, organization, research result) in R&D Ontology. In the National R&D Knowledge Map, center-node is the object selected by users, node is subject, subject's sub-node is user's favorite query in National R&D ontology after analyzing the relationship between object and subject. When a user selects sub-node, the system displays the results from inference engine after making query by SPARQL in National R&D ontology.

• Journal of the Korean Applied Science and Technology
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• 제34권2호
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• pp.289-295
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• 2017

The International Maritime Organization (IMO) in accordance with the regulations with respect to the combustion gases, such as NOx, SOx generated by the marine engine. The combustion gases must be equipped with a device to reduce emissions from all ships passing through the Baltic SECAs. In Korea, the International Maritime Organization (IMO) and the development of a device for NOx, SOx reduction. Scrubber is used in the ammonia water and the Urea solution in the waste water. The waste water containing ammonium nitrate and ammonium sulfate, react of the NOx and SOx gas. In this study, the recovery of by-product, which contains the waste water was used as an organic solvent extraction method of salting out. Ammonium nitrate and ammonium sulfate, the recovery process. A qualitative analysis of the collected by-product FT-IR analysis. Through the elemental analysis and SEM-EDS, characteristic evaluation was performed with an impurity.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제15권1호
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• pp.229-235
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• 2015

ICT healing platform is based on bio-signal and life habit information target to alarm early sickness concept prevention chronic pain. ICT(Information & Communication Technology) healing platform target on personal lead health management care of several health agencies and open of the (hospital, fitness center, health examination center, personal health device) personal health information together to personal device. Support Analysis Platform and Open API to vitalization optional services. In this paper proposal to access personality healing data Open Gateway Framework of Healing Platform Adaptor (HPAdaptor) ICT healing platform means Data relaying link to EMR(Electronic health record), korean medicine, life log, wellness, chronic pain, and fineness several personal health data provider and service provider personal healing data with software engine. After Design HPAdaptor can use for data and service provider record storage, mobile platform and analytics platform need data service or platform relying reference model.

• Tunnel and Underground Space
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• 제13권3호
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• pp.235-243
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• 2003

Recent worldwide trends show that tunnel length is getting longer, and the demand for longitudinal ventilation system with jet-fans in highway tunnels has also increased mainly due to the economic reasons. Improvements in vehicle engine subsequently reduced required ventilation rate(Qreq) which is the decisive factor in choosing the optimal ventilation system. Qreq contour map is a graph that defines the relationship among tunnel length, grade and required ventilation rate. It is important to understand the variation of Qreq in order to evaluate the characteristics of ventilation system with jet fans. Therefore this study aims at studying a graphical method for determining the characteristics of jet-fm ventilation system using Qreq contour map. Also, this study focuses on traffic composition on local highways.

• Journal of Internet Computing and Services
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• 제16권6호
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• pp.23-30
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• 2015

As BigData is issued, many applications that operate based on the results of data analysis have been developed, typically applications are products recommend service of e-commerce application service system, search service on the search engine service and friend list recommend system of social network service. In this paper, we suggests a decision frequent pattern tree that is combined the origin frequent pattern tree that is mining similar pattern to appear in the data set of the existing data mining techniques and decision tree based on the theory of computer science. The decision frequent pattern tree algorithm improves about problem of frequent pattern tree that have to make some a lot's pattern so it is to hard to analyze about data. We also proposes to model for a Mapredue framework that is a programming model to help to operate in distributed environment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제41권3호
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• pp.185-193
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• 2013

The plume infrared signature effects at various flight conditions of aircraft were investigated for the purpose of reducing infrared signature level. The nozzle of a virtual subsonic unmanned combat aerial vehicle was designed through a performance analysis. Nozzle and associated plume flowfields were first analyzed using a density-based CFD code and plume IR signature was then calculated on the basis of the narrow-band model. Finally, qualitative information for the plume infrared signature characteristics was obtained through the analysis of the IR signature effects at various flight conditions.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제41권4호
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• pp.253-260
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• 2013

Ice accretions on the surface around a rotorcraft air intake can deteriorate the safety of rotorcraft due to the engine performance degradation. The computational simulation based on modern CFD methods can be considered extremely valuable in analyzing icing effects before exact but very expensive icing wind tunnel or in-flight tests are conducted. In this study the range and amount of ice on the surface of anti-icing equipment are investigated for heat-on and heat-off modes. It is demonstrated through the computational prediction and the icing wind tunnel test that the maximum mass and height of ice of heat-on mode are reduced about 80% in comparison with those of heat-off mode.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제36권1호
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• pp.62-71
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• 2008

Swirl injector with adjustable backhole length was analyzed to suppress high-frequency combustion instability in Liquid Rocket Engines. In order to analyze the effect of swirl injector as an acoustic absorber, swirl injector was regarded as a quarter-wave resonator and its damping capacity is verified in atmospheric temperature. Experiments were carried out with copied tubes on air core because the interior air core volume of injector has a direct effect on damping. From the experimental data, it is proved that increasing the number of injectors mounted at each anti-node point can increase acoustic damping effect. Also, when tuned injectors at 1L, 1T, 1L1T modes simultaneously are installed at each anti-node point of model chamber, the damping effect of tuned injectors with multi modes agree well with it of tuned injectors with single mode.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제34권10호
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• pp.71-79
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• 2006

Swirl injector with multi-stage tangential entry was analyzed to suppress high-frequency combustion instability in Liquid Rocket Engines. In order to analyze the effect of swirl injector as an acoustic absorber, swirl injector was regarded as a quarter-wave resonator and it's damping capacity is verified in atmospheric temperature. It has a finite mode of vibration and natural frequencies which can be tuned to the natural frequencies of a model combustion chamber. The interior air core shape of injector is more stable in the case of using the swirl injector with multi-stage entry than with single-stage entry. Also, when the swirl injector with multi-stage entry is used, tuned-injector length for unstable mode is well agreed with the calculated length. From the experimental data, it is proved that if the interior air core shape of swirl injector is stable, the fine tuned swirl injector can decrease the unstable mode of model chamber effectively and increase the damping rate.