• Korean Journal of Environmental Biology
• /
• v.17 no.1
• /
• pp.95-115
• /
• 1999

The dynamics of phytoplankton community in Lake Imha and its tributaries was investigated at nineteen stations in August and September 1996. A total of 171 taxa ［171 species (including 1 forms and 27 varieties),66 genus, 25 families, 6 suborders, 13 orders and 6 class］ were identified. The standing crops of phytoplankton ranged from $47.35{\times}10^3 to 184.65{\times}10^3 individuals/ml in surface layer, 1.08{\times}10^3~54.33{\times}10^3 individuals/ml in middle layer and 0.69{\times}10^3~115.85{\times}10^3individuals/ml$ in low layer. Dominant species determined by standing crops of each species were Oocystis lacustris, Elakatothrix gelatinosa, Aulacoseira ambigua, and Synedra acus, however, the most species dominated from 1992 to 1994 disappeared.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.9
• /
• pp.6269-6273
• /
• 2015

Performance of the Alamouti algorithm based M-ary $2{\times}N$ OSTBC(Orthogonal Space Time Block Coded) MIMO(Multi Input Multi Output) system has been simulated varying two main parameters - the number of constellation(M), and the number of receiving antennas(N). Computer simulation has also been carried out using Matlab software for performance comparison between $2{\times}N$ MIMO and MRC(Maximal Ratio Combining) diversity antenna system to evaluate the degree of enhancement achieved through the use of Alamouti $2{\times}N$ MIMO. Under 10 dB EbNo QPSK scenario, $2{\times}1$ MIMO brought 4.2 dB BER improvement over single antenna system and $2{\times}2$ MIMO resulted in 7.4 dB BER improvement over $1{\times}2$ MRC.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.47 no.1
• /
• pp.77-83
• /
• 2010

Radiation characteristics of $5{\times}4$ pin array patch antennas are compared to those of $5{\times}2$ pin array patch antennas for several substrate thicknesses using the computer simulation. Since the number of unit cells of a $5{\times}2$ pin array patch antenna is half of that of a $5{\times}4$ pin array patch antenna, the number of pins used in a $5{\times}2$ pin array patch antenna is half of that in a $5{\times}4$ pin array patch antenna and the patch width of a $5{\times}2$ pin array patch antenna is very small compared to that of a $5{\times}4$ pin array patch antenna. However, the radiation characteristics of a $5{\times}2$ pin array patch antenna are almost similar to those of a $5{\times}4$ pin array patch antenna.

• Journal of The Korean Society of Integrative Medicine
• /
• v.5 no.4
• /
• pp.103-112
• /
• 2017

Purpose : This study was conducted to improve cognitive oral healthcare care by analyzing the correlation between oral health behavior and oral health status Korean adolescents. The subjects were 65,528 youths in 798 schools monitored in the Twelfth Korea Youth Risk Behavior Web-based Survey in 2016. Methods : The general characteristics consisted of 9 items including sex, grade, and academic performance. The academic performance and economic status were restructured into "upper, middle, lower". Subjective health perception and subjective oral health perception were reorganized as "health", "normal", "no health". The sub-areas of oral health behavior include five times of daily brushing during the day yesterday. The number of brushing times was "0", "1-2", "3", "more than 4" After lunch at school, brushing was restructured as "always," "sometimes," "not." The oral health status subscale consisted of 6 items including tooth breakage and toothache at the time of eating. Result : Tooth fracture(43.7 %), pain in mastication(43.7 %), tooth tingling(47.4 %), gum pain and bleeding(45 %), pain in buccal mucosa(43.8 %) and halitosis(46.6 %) were rare in adolescent having healthy oral health status cognitively(P<.001). Nosymptom adolescents without dental sealant showed low tooth fracture(0.64 times), pain in mastication(0.67 times), tooth tingling(0.59 times), gum pain and bleeding(0.84 times), pain in buccal mucosa(0.76 times), and halitosis(0.90 times). Nosymptom adolescents without scaling showed low tooth fracture(0.88 times), pain in mastication(1.03 times), tooth tingling(0.82 times), gum pain and bleeding(0.64 times), pain in buccal mucosa(0.70 times) and halitosis(0.82 times). Conclusion : This study revealed that oral health status is correlated with oral health behavior. Development of educational media and program, and aggressive promotion required to establish oral health Korean adolescent.

• Journal of the Korean Electrochemical Society
• /
• v.5 no.1
• /
• pp.13-16
• /
• 2002

The type of graphite(Gr)/ppy, fullerene$(full^-)$ electrode, ppy one modified with $(full^-)$, was prepared with the cell type of Gr/5mM ppy, 1mM $(full^-)$, 0.1M $TBABF_4$, CH3CN/Pt. The values of the ionic formation rate of the it at electrode materials such as Pt/ppy, Pt, Gr and Au were $93.6,\;7.0\times10^2,\;42.6\;and\;1.3\times10^2cms^{-1}$ respectively. The admittance values of the Grippy electrode and the modified Grippy, $(full^-)$ one were five times enhanced $1.7\times10^{-3}S\;to\;8.3\times10^{-3}\;S$ and capacitance values of electrical double layer of them were 174 times increased $2.4\times10^{-6}\;F\;to\;4.2\times10^{-5}\;F$ respectively.

• Progress in Medical Physics
• /
• v.6 no.2
• /
• pp.93-101
• /
• 1995

In this paper, we implemented a digital medical image management and a remote monitor display system for a personal computer. The designed system can display up to a 1280${\times}$1024 image which can accomodate eight images with a 256${\times}$256${\times}$8bits. When one of these images is clicked by the mouse, the selected image can be displayed with 256${\times}$256${\times}$8bits or 1024${\times}$1024${\times}$8bits. For the selected image, we can use one of the image processing functions in this system and send it to a remote monitor for the close examinations. To search and store digital images effectively, we constructed and image database management system with the B＋TREE structure. This system can be operated in an IBM-PC 386 or higher and all the function are performed easily with a mouse to provide a user firendly environment.

• Journal of Korean Society of Steel Construction
• /
• v.12 no.6
• /
• pp.769-777
• /
• 2000

This paper presents the results of cyclic seismic performance in relation to beam-panel zone strength ratio of CFT Column to H-beam steel moment connections. Each test specimen consisted of $H-350{\times}175{\times}7{\times}11$ beam(SS400) and ${\boxe}-250{\times}250{\times}9$, ${\boxe}-250{\times}250{\times}12$ column(SPSR400). Main parameter is a column panel zone strength relative to beam strength. Energy absorption capacity available in the specimens ranged from 5.2 to 12.7(tm). If panel zone strength relative to beam strength is too strong or weak, the energy absorption capacity tended to be inferior. About steel moment-resisting frame, the test results of this experiment seem to support the investigation that permitting panel zone yielding shall be more advantageous to enhancing total seismic performance.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.48 no.3
• /
• pp.42-49
• /
• 2011

In this paper, we propose a fast macroblock mode decision algorithm in H.264/AVC, based on the image sequence statistics. Specically, considering the directional characteristics of image sequences, we eliminate sub$8{\times}4$ or sub$4{\times}8$ mode decision process based on the rate-distortion cost of Inter$16{\times}8$ or Inter$8{\times}16$ mode respectively. Additionally, exploiting the optimal modes of submacroblock in inter$8{\times}8$ mode, we propose an algorithm to eliminate Intra$4{\times}4$ or Intra$16{\times}16$ mode decision process selectively. From the simulation results, the proposed method reduce the encoding time by maximum 70% of total, compared with the other conventional methods.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.22 no.3
• /
• pp.49-61
• /
• 2020

This study analyzed the social media accounts and performed a Big Data analysis of Z-generation fashion using Textom Text Mining Techniques program and Ucinet Big Data analysis program. The research results are as follows: First, as a result of keyword analysis on 67.646 Z-generation fashion social media posts over the last 5 years, 220,211 keywords were extracted. Among them, 67 major keywords were selected based on the frequency of co-occurrence being greater than more than 250 times. As the top keywords appearing over 1000 times, were the most influential as the number of nodes connected to 'Z generation' (29595 times) are overwhelmingly, and was followed by 'millennials'(18536 times), 'fashion'(17836 times), and 'generation'(13055 times), 'brand'(8325 times) and 'trend'(7310 times) Second, as a result of the analysis of Network Degree Centrality between the key keywords for the Z-generation, the number of nodes connected to the "Z-generation" (29595 times) is overwhelmingly large. Next, many 'millennial'(18536 times), 'fashion'(17836 times), 'generation'(13055 times), 'brand'(8325 times), 'trend'(7310 times), etc. appear. These texts are considered to be important factors in exploring the reaction of social media to the Z-generation. Third, through the analysis of CONCOR, text with the structural equivalence between major keywords for Gen Z fashion was rearranged and clustered. In addition, four clusters were derived by grouping through network semantic network visualization. Group 1 is 54 texts, 'Diverse Characteristics of Z-Generation Fashion Consumers', Group 2 is 7 Texts, 'Z-Generation's teenagers Fashion Powers', Group 3 is 8 Texts, 'Z-Generation's Celebrity Fashions' Interest and Fashion', Group 4 named 'Gucci', the most popular luxury fashion of the Z-generation as one text.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.41 no.1
• /
• pp.21-28
• /
• 2017

Indirect evaporative cooling, which utilizes a cooling effect obtained by the evaporation of water, is energy-effective compared to the conventional vapor compression method. It is also eco-friendly, due to the non-usage of CFC refrigerant. In this study, three indirect evaporative cooler samples of the cross flow type(size: $300mm{\times}300mm{\times}300mm$, channel pitch: $5mm{\times}5mm$, $5mm{\times}7mm$, $7mm{\times}7mm$) were made using plastic/paper composites. Tests were conducted to measure indirect evaporative efficiencies and pressure drops. Results showed that the efficiency was the highest for the $5mm{\times}5mm$ sample, owing to the largest surface area. The saved electrical energy was also the greatest for that sample. The pressure drop of the wet channel was larger than that of the dry channel as expected. A theoretical model was proposed, which underestimated both the indirect evaporation efficiency and the pressure drop.