• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.667-671
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• 2012

Low frequency noises (up to about 200 Hz) mainly occur due to particular modes, resulting in booming noises, and in general the solutions may be found based on mode controls where conventional methods such as FEM can be used. However, at higher frequencies between 0.3~ 1 kHz, as the number of modes rapidly increase, radiation characteristics from structures, performances of damping sheets and sound packages may be more crucial rather than particular modes, and consequently the conventional FEM may be less practical in dealing with this kinds of structure-borne problems. In this context, so-called 'mid-frequency simulation model' based on FE-SEA hybrid method is studied and validated. Energy Transmission loss (i.e. air borne noise) is also studied. A dash panel component is chosen for this study, which is an important path that transfers both structure-borne and air borne energies into the cavity. Design modifications including structural modifications, attachment of damping sheets and application of different sound packages are taken into account and the corresponding noise characteristics are experimentally identified. It is found that the dash member behaves as a noise path. The damping sheet or sound packages have similar influences on both sound radiation and transmission loss. The comparison between experiments and simulations shows that this model could be used to predict the tendency of noise improvement.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.8
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• pp.946-952
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• 2013

Large scale fire tests were conducted to develop water mist nozzles as a component of fixed water- based fire fighting systems for Ro-Ro spaces and special category spaces. Fire scenarios for this system consist of two cases which are for cargo fire in a simulated truck and for passenger vehicle fire, and each case has 3 different tests according to the position between fixed water mist nozzles and fire source. Every experiment proceeded for 30 minutes and acceptance criteria were based on gas temperature, fuel package's damage and ignition of targets. This study primarily dealt with the experimental results of cargo fire and focused on fire suppression capability in accordance with discharge pressure, flow rate and flow characteristics like swirl and penetration of the developed water mist nozzles. It appeared that low pressure water mist nozzles with about 40 L/min were able to control fire occurred in Ro-Ro spaces.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.2015-2020
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• 2012

Oleanolic acid (OA) is a naturally occurring triterpenoid in food materials and is a component of the leaves and roots of Olea europaea, Viscum album L., Aralia chinensis L. and more than 120 other plant species. There are several reports validating its antitumor activity against different cancer cells apart from its hepatoprotective activity. However, antitumor activity against skin cancer has not beed studied well thus far. Hence the present study of effects of OA against HaCaT (immortalized keratinocyte) cells - a cell-based epithelial model system for toxicity/ethnopharmacology-based studies - was conducted. Radical scavenging activity ($DPPH{\cdot}$) and FRAP were determined spectrophotometrically. Proliferation was assessed by XTT assay at 24, 48 and 72 hrs with exposure to various concentrations (12.5-200 ${\mu}M$) of OA. Apoptotic induction potential of OA was demonstrated using a cellular DNA fragmentation ELISA method. Morphological studies were also carried out to elucidate its antitumor potential. The results revealed that OA induces apoptosis by altering cellular morphology as well as DNA integrity in HaCaT cells in a dose-dependent manner, with comparatively low cytotoxicity. The moderate toxicity observed in HaCaT cells, with induction of apoptosis, possibly suggests greater involvement of programmed-cell death-mediated mechanisms. We conclude that OA has relatively low toxicity and has the potential to induce apoptosis in HaCaT cells and hence provides a substantial and sound scientific basis for further validation studies.

• Journal of Korea Multimedia Society
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• v.1 no.1
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• pp.1-17
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• 1998

Video information is an important component of multimedia systems such as Digital Library, World-Wide Web (WWW), and Video-On-Demand (VOD) service system. Video information has hierarchical document structure inherently, so it is named "structure video document" in this paper. This paper proposes a data model, a query language, and an indexing scheme for structured video documents in order to store, retrieve, and share video documents efficiently. In representing structured video documents, the object-oriented data modeling technique is used since the hierarchical structure information can be modeled as complex objects. We also define object types for the structure information. Our query language supports not only content-based retrieval, which means the queries based on the structure of video documents, and spatial/temporal relation for video documents. In order to perform structure queries efficiently, as well as to reduce the storage overhead of indices, an optimized inverted index structure is proposed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.8B
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• pp.796-801
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• 2002

CL1(closed loop mode 1) is one of the closed loop transmit diversity schemes defined by 3GPP WCDMA and adjusts the relative phases of the transmitted signals at the two transmit antennas, thereby maximizing the power of the received signal at the user equipment. A key component of this scheme is to encode the phase difference between two received signals arrived at the user equipment via two different transmit antennas and to send it back to the base station. This paper proposes a new phase difference representation based on the adaptive delta modulation and compares its performance with the corresponding one of CL1. Computer simulations show that, in a slowly fading environment, the proposed scheme produces more realistic representation of the phase difference than the on of the CL1, resulting in a lower BER.

• Journal of Veterinary Clinics
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• v.29 no.1
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• pp.58-62
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• 2012

To protect aquatic animal health of importing countries from the potential risks associated with exotic diseases introduced through international trade of live aquatic animals, inspection of designated commodities at ports of entry is a critical component of the safeguarding system. The only way to be 100% confident that no fishes in a shipment are infected with a specific agent is to test every fish in the commodity imported with a perfect diagnostic test. For the majority of cases, this is unrealistic since the group of interest may very large particularly for aquatic animals, or imperfect tests are often available. It is, therefore, more common to test a fixed proportion of a group by preplanned sampling schemes. However, decision making based on results of testing the sample can provide quite a chance that infected groups may be misclassified as uninfected, depending on sampling strategy employed. The objective of this study was to determine the possibility that one or more fishes in the group imported being infected but tests negative after inspecting samples. This question is critical to government authorities to examine whether sampling plan is sufficient to achieve the purpose intended for. At fixed population size, the maximum number of infected fishes when all tests negative was decreased as the sampling fraction increased. The probability of including at least one undetected but infected fish in a group for negative tests increased with the number of fish tested or true prevalence. The risk was much lesser where high sensitivity test was assumed; when increasing test sensitivity from 0.9 to 0.99, this risk was dramatically reduced to about a tenth or a fourth for prevalence ranges from 2 to 10%, given sample size ranges from 10 to 200. Based on the preliminary analysis, the author concluded that current sampling plan testing 4-8% of the import proposal for human consumption still can yield high false negative results. Therefore, from the quarantine inspection point of view, an enforced commodity-specific sampling design that accounts for the cost of testing with an imperfect test at the specified design prevalence is urgent.

• Journal of Korean Society on Water Environment
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• v.22 no.2
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• pp.244-249
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• 2006

Natural environment of Weolgokri watershed has been well preserved as a traditional agricultural watershed. A year record of streamflow, $NO_3-N$, T-N and T-P concentrations data (April 2004 - Mar. 2005) were examined to estimate annual and seasonal patterns of pollutant loads in streamflow and baseflow from the agricultural watershed. To estimate pollutant loads from baseflow, baseflow component was separated from streamflow using the digital filter method in the Web-based Hydrograph Analysis Tool system and loads of $NO_3-N$, T-N and T-P from streamflow and baseflow were evaluated. The $NO_3-N$, T-N, and T-P loads from streamflow were 13.85 kg/ha, 45.92 kg/ha and 1.887 kg/ha, respectively, while corresponding loads from baseflow were 7.43 kg/ha, 24.70 kg/ha, 0.582 kg/ha, respectively. It was found that $NO_3-N$ and T-N loads were contributed slightly more by the baseflow (53% and 53% of Total-loads) than by the direct runoff (47% and 47% of Total loads). However, only 30% of total T-P load was contributed by the baseflow. It is recommended that one needs to assess pollutant load contribution by the baseflow to identify appropriate pollution control strategies for an effective watershed management.

• Journal of Korean Society on Water Environment
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• v.36 no.5
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• pp.364-372
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• 2020

The "Master Plan for the Revitalization of Water in the Nakdong River" is designed for the fundamental improvement of water quality in the Nakdong River. The water quality and flow of the Nakdong River system tributaries was monitored in this study. Among the living environmental standard parameters of 195 rivers, BOD (Biochemical oxygen demand), T-P (Total phosphorus) and TOC (Total organic carbon) were assessed to analyze the water quality from 2012 to 2019. We examined the role of TOC. It was found that 12 rivers exceeded the water quality of the second grade (3.0 mg/L BOD standard, 0.1 mg/L T-P standard, 4.0 mg/L TOC standard) based on BOD and T-P concentrations: the Gumi stream, Gisegok stream, Yongha stream, Yongho stream, Changnyeong stream, Gajwa stream, Gwangok stream, Yeongsan stream, Toerae stream, Hwapo stream, Sangnam stream and Hogye stream. These rivers require strategies to improve the quality of the Nakdong River. Based on the ongoing project, it is possible to supplement the "Master Plan for the Revitalization of Water in the Nakdong River" and manage it after verifying it as a component of people's life and therefore used to establish water quality control measures.

• Korean Journal of Materials Research
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• v.23 no.5
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• pp.286-292
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• 2013

Generally, the color gold has had a biased conception due to its traditional use. Thus, this bias has resulted in a lack of usage of golden glaze on ceramics and also a lack of extensive studies of such glazes. In this paper, optimum conditions and mechanism of formation of gold color crystallization glaze containing $Fe_2O_3$(hematite), which is developed for gold colors of ceramic glazes, were studied. Experimental result showed that there are pyroxene based on diopside and $TiO_2$ phase in the base of a crystallization glaze with a value of $TiO_2$ of 6 wt% confirmed by XRD and Raman Spectroscopy. When $Fe_2O_3$ was used as a colorant for the gold color, the $TiO_2$ peak became extinct and the intensity of the diopside peak was sharper. Feldspar of 60 wt%, talc of 20 wt% and limestone of 20 wt% were used as the starting materials and these were tested using a three component system. The best result of test was selected and extended to its vicinity as an experiment to determine $TiO_2$ and $Fe_2O_3$ contents. The glaze with $TiO_2$ of 6 wt% and $Fe_2O_3$ of 12 wt% addition showed stable pyroxene based diopside crystals and the development of gold color. This gold color was obtained with CIE-$L^*a^*b^*$ values of 51.27, 4.46, 16.15 (a grayish yellow brown color), which was gained using the following firing conditions: temperature increasing speed $5^{\circ}C$/min, holding for 1 h at $1280^{\circ}C$, annealing speed $3^{\circ}C$/min till $1100{\circ}C$, holding for 2 h at $1100{\circ}C$, and finally natural annealing.

• Smart Structures and Systems
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• v.26 no.4
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• pp.495-506
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• 2020

Monitoring of complex processes faces several challenges mainly due to the lack of relevant sensory information or insufficient elaborated decision-making strategies. These challenges motivate researchers to adopt complex data processing and analysis in order to improve the process representation. This paper presents the development and implementation of quality monitoring framework based on a model-driven approach using embedded artificial intelligence strategies. In this work, the strategies are applied to the supervision of a microfabrication process aiming at showing the great performance of the framework in a very complex system in the manufacturing sector. The procedure involves two methods for modelling a representative quality variable, such as surface roughness. Firstly, the hybrid incremental modelling strategy is applied. Secondly, a generalized fuzzy clustering c-means method is developed. Finally, a comparative study of the behavior of the two models for predicting a quality indicator, represented by surface roughness of manufactured components, is presented for specific manufacturing process. The manufactured part used in this study is a critical structural aerospace component. In addition, the validation and testing are performed at laboratory and industrial levels, demonstrating proper real-time operation for non-linear processes with relatively fast dynamics. The results of this study are very promising in terms of computational efficiency and transfer of knowledge to manufacturing industry.