• Journal of the Korean Data and Information Science Society
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• 제14권4호
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• pp.889-901
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• 2003

In this paper, we consider the optimal replacement policies following the expiration of the combination warranty. The combination warranty can be divided into the renewing combination warranty and the non-renewing combination warranty. The criterion used to determine the optimal replacement period is the overall value function based on the expected cost and the expected downtime. Thus, we obtain the expected cost rate per unit time and the expected downtime per unit time for our model. And then the overall value function suggested by Jiagn and Ji(2002) is applied to obtain the optimal replacement period. The numerical examples are presented for illustrative purpose.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2001년도 추계 수산관련학회 공동학술대회발표요지집
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• pp.204-205
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• 2001

Manful algae, Cochlodinium polykrikoides has damaged to fisheries organisms by making massive blooms mainly in the South Sea during the higher water temperature season since 1995 in Korea. Ecological and hydrodynamic studies of the species offer useful information in understanding its bloom mechanism giving promising data for the modeling and prediction of the blooms. (omitted)

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 B
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• pp.513-515
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• 1997

The main purpose of this study was to develope the prototypes of on-line supervision system for maintenance to protect the confidence of operation of electric facilities in buildings. The influence of the harmonics on the electric facilities in building, which is recently growing more and more serious, were also analysed, and finally the essential techniques on the condition supervision, diagnosing method of facilities were proposed.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2009년도 한국우주과학회보 제18권2호
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• pp.38.2-38.2
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• 2009

The ionosphere displays variations on a wide variety of time-scales, ranging from few hours to days and up to solar cycles and even more. In this paper, we examine the ionospheric F2-layer variability in mid latitude by analyzing the foF2 and hmF2 from the Anyang ionosonde. Especially, we investigate how ionospheric semi-annual and seasonal anomalies vary with local time and solar activity. In addition to the characterization of the ionospheric semi-annual an seasonal anomalies, our study extends to the investigation of the relationship between ionospheric variability and geomagnetic activity. Finally we also discuss the coupling between ionospheric F2-layer variability and thermospheric neutral composition.

• 대한가정학회지
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• 제44권1호
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• pp.131-138
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• 2006

The yanggwan is a striped headpiece for civil and military officials worn with jebok, a costume for the royal ancestral worship ceremony, or jobok, a ceremonial costume for the courtier. It was called a jegwan when it was worn with a jebok. The geumgwan and jegwan are of the same style but the geumgwan has a gilded band and backside and the jegwan is mostly lacquered. The yanggwan was worn first with the jebok by the officials, both of which were received from the Chinese Ming dynasty in the 19th year of the King Gongmin's reign during the Goryeo period. The royal crown and court clothing system was two grades lower than the standard clothing code of the Ming dynasty of China. In the Joseon dynasty, the oyanggwan worn by the highest grade officials had five-stripes but was later replaced during the Daehan Empire by the seven-striped chilyanggwan used by Ming dynasty officials. Oyanggwans make up the majority of the surviving examples of these headpieces, with the exception of the six-striped yukyanggwan of Chung In-hak (1839-1919), the Minister of Justice, which originated in the Daehan Empire and whose owner is definitively known. The gilt portion of this yukyanggwan is finely engraved in relief with a bird, flower and tendril motif. The yukyanggwan is topped by a decorative bird ornament, called a jeongkkot. EDSS spectrum analysis of the gold plating reveals a composition of 51.32% gold and 10.34% silver. The yanggwan is composed of bamboo, mulberry paper and silk crepe. The black portions are lacquered. The individual yang is made with twisted mulberry paper.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.796-805
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• 2005

The tilting pad journal bearings have been widely used to support high pressure/high rotating turbine rotors owing to their inherent dynamic stability characteristics. However, fatigue damages in the upper unloaded pads and the break of locking pins etc. by pad fluttering are continuously taken place in the actual steam turbines. The purpose of this paper is to develop a new bearing model that can prevent bearing problems effectively by pad fluttering in a tilting pad journal bearing. A new bearing model which has a wedged groove is suggested from the studies of fluttering mechanism performed by previously research works. The fluttering characteristics of the upper unloaded pad are studied experimentally in order to verify the reliability of a new bearing model. It can be known that the phenomenon of pad fluttering nearly does not occurred in the new bearing model under the various experimental conditions. And it is observed that any kinds of bearing failures by pad fluttering does not detect in the application of acture steam turbines.

• Tuberculosis and Respiratory Diseases
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• 제38권1호
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• pp.70-73
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• 1991

We have experienced a case of lung injury caused by accidental inhalation of ammonia gas in a 34 year-old-man. By the explosion of ammonia tank in a refrigerator boat he inhaled ammonia gas. Several minutes later, he suffered from severe dyspnea and visual loss. On arrival at emergency room, analysis of arterial blood gas revealed severe hypoxemia and his chest film showed bilateral pulmonary infiltrates. Under the impression of adult respiratory distress syndrome, mechanical ventilator was applied to the patient. After recovery from ARDS and tracheal edema, he complained of some hemoptysis and productive sputum during the admission. So we checked bronchoscopy and bronchograpy which showed tracheal bullae just above carina and tubular bronchiectatic change in the right lower lobe. We report a case of lung injuries-ARDS, tracheal bullae, and bronchiectasis-caused by inhalation of ammonia gas with the review of the relevant literatures.

• 한국기계가공학회지
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• 제21권1호
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• pp.34-40
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• 2022

In this paper, a flow analysis of a swash-plate type hydraulic piston pump installed on a hydraulic flow supply system for marine vessels is presented. A model and governing equations for computational fluid dynamics (CFD) analyses of swash-plate type hydraulic piston pumps were built, and simulation results regarding the internal flow field of the pump were obtained. By analyzing the internal flow of the swash-plate type hydraulic piston pump, we can confirm the time-dependent stroke of each piston as the pump rotates. We also verified that by analyzing the pulsating flow against the slope of the swash plate, the simulation results match well with the experimental results. The natural frequency of the system was computed to be approximately 380 Hz by applying and analyzing the fast Fourier transform (FFT) of each swash plate slope evaluated.

• 한국양식학회:학술대회논문집
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• 한국양식학회 2003년도 추계학술발표대회 논문요약집
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• pp.136-137
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• 2003

The marine dinoflagellate genus Alexandrium has been recognized as the most representative toxic phytoplankton on account of production of paralytic shellfish poisoning (PSP) throughout the world. PSP producers, generally A, tamarense and A. catenella, within the genus Alexandrium have caused high level intoxicauon of fisheries products and even death of human. In addition, more recent increasing of geographical range of this deleterious species has given rise to alarming tension. The study presented here aimed construction of the molecular phylogenetic relationships through sequences-determination from 16 morphotypic species (containing newly sequenced 3 morphotypic species, A. tamiyavainchii, A. fraterculus and A. pseudogonyaulax) in LSU rDNA D1-D2 and 12 morphotypic species (containing newly sequenced 6 - morphotypic species, A. catenella, A. tamiyavanichii, A. fraterculus, A. affine, A. insuetum and A. pseudogonyaulax) in SSU rDNA region, and the sequences were subjected to comparative-analysis in respect to regional population using functionally expressed rDNA genus and pseudogenes. And we discussed on genetic differentiation between A. tamarense and A. catenella together with putative PSP divegence of the genus Alexandrium. The results of phylogenetic analysis showed the robust monophyletic 14 distinct classes of A. tamarense, A. excavatum, A. catenella, Tasmanian A. tamarense, A. affine (and/or A. concavum), Thai A. tamarense, A. tamiyavanichii, A. fraterculus, A. margalefii, A. andersonii, A. ostenfeldii, A. minutum (and/or A. lusitanicum), A. insuetum, and A, pseudogonyaulx clade. A. fraterculus and A. tamiyavanichii were sister relationship and they were positioned independently between A, affine cluster and those of A. margalefi, A. andersonii, A. ostenfeldii, A. minutum and A. insuetum. A. pseudogonyaulax appeared to be an ancestral taxon among Alexandrium.

• 한국양식학회:학술대회논문집
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• 한국양식학회 2003년도 추계학술발표대회 논문요약집
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• pp.134-135
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• 2003

The geographic expansion of the toxic dinoflagellates genus Alexandrium has been shown to be world wide ranging. The members of the genus Alexandrium ocnstituted of 20-30 species did not show substantial differences in their morphology, which is mostly referred in the 'tamarensis species complex', except some species. Though rDNA sequences variations are very few and pseudogene types are so diverse that it is difficult to use them as the specific markers. In this study, we outlined Korean and Japanese A, tamarense and A. catenella regional isolates by phylogenetic analysis inferred from no cutting alignments of LSU rDNA D1-D2 and SSU rDNA sequences to group these regional isolates. The results were compared to RFLP patterns of PCR products targeted chloroplast DNA. Lastly screening of highly repeated microsatellite DNA which is frequently used for population analysis in eukaryotes was conducted. A. catenella regional strains identified by the sequencing of rDNA D1-D2 domain were divided into at least 3 groups of type E, CMC and Chinese type, divergence root may not be deep comparing with that of A. tamarense whose pseudogenes are very variable. Results of RFLP pattern and the phylogeny of the unknown gene targeting chloroplast showed that Korean and Japanese A. catenella regional isolates were divided into 3 types: Korean, Japanese and the third CMC types. Population-specific PCR amplification with Japanese A. catenella type-specific PCR primers was useful method for population analysis of A. catenella. Various types of satellite sequences such as 5 nucleotides repeats were obtained from A. tamarense and A. catenella. The 5 nucleotides repeats were primed at the both 3'and 5' ends, and these repeats were prominent as longer repeated motifs. This repeated DNA was intercalated as internal sequences containing various types subrepeats. It is expected that these satellite DNA would be a useful molecular population marker through detail comparison among Alexandrium regional isolates to trace their transferring pathway and to prevent their human-associated their regional extents.