• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1A
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• pp.9-17
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• 2004

Adapt ive and fixed step size PC (power control) schemes for accommodating voice, video, and data are evaluated according to the different PC command rates and their effects on integrated Voice/Video/Data are investigated. The required minimum power levels are derived as PC thresholds and the effects of PC errors on channel quality and radio 1 ink capacity are investigated. The services with high bit rates and low bit error rates can cause a significant effect on the radio link qualifies of the other types of traffic. The results show that the adapt ive step size PC scheme for voice/video/data services can achieve more capacity and cause less interference to the radio channels because less minimum PIL(Power Increment Level) is required for the specified radio link outage probability.

• Reproductive and Developmental Biology
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• v.35 no.2
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• pp.137-141
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• 2011

These study was to investigate the in vitro fertilization and viability of fresh and vitrified oocytes. Also, the developmental capacity of IVF and intracytoplasmic sperm injection (ICSI) oocytes were investigated. Then vitrification was performed with the use of 20% ethylene glycol + 20% DMSO + 0.5 M sucrose + 10% FCS + TCM-199 medium. Vitrification immature oocytes are cultured in vitrification solution for 10 min afterwards transferred to expose at room temperature for 5 min. and transferred to the ice water for 5 min. The oocytes were sealed in a 1.0 mm straw and placed in a $LN_2$ container. Frozen oocytes were rapidly thawed in a water bath at $30{\sim}35^{\circ}C$, and then placed in TCM-199 medium containing 0.5 M sucrose for 5 min each, respectively, at $38^{\circ}C$. After being washed for 2~3 times, using fresh medium the oocytes were cultured in TCM-l99 medium supplemented with 5% FCS at $38^{\circ}C$ in 5% $CO_2$ and air. The normal morphology of fresh and vitrified-thawed oocytes were $87.1{\pm}2.1%$ and $54.8{\pm}2.5%$, respectively. The viability rates of fresh and vitrified-thawed oocytes were $70.0{\pm}2.2%$ and $41.9{\pm}2.6%$, respectively. Viability rates of vitrified-thawed oocytes were lower than that of fresh follicular oocytes (p<0.05). The in vitro maturation rates of fresh and vitrified oocytes were $45.1{\pm}3.6%$ and $28.9{\pm}4.4%$, respectively. The IVF rates of fresh follicular and vitrified-thawed oocytes were 34.00.2% and $20.2{\pm}2.6%$, respectively. The in vitro maturation and fertilization rates of vitrified-thawed oocytes were lower than those of the fresh follicular oocytes (p<0.05). A total of 350 oocytes were fixed and stained after co-incubation with spermatozoa, of which 88 had identifiable nuclear material. After IVF for 20 hrs, $25.1{\pm}3.4%$ of the oocytes found to have been penetrated by spermatozoas. Oocytes were fixed and stained after ICSI, and 105 oocytes contained identifiable nuclear material. After IVF and ICSI for 20 hrs, $34.3{\pm}3.4%$ and $59.0{\pm}2.0%$ of the oocytes were found to have been penetrated by spermatozoas. The developmental rates upon ICSI were significantly higher than those of the IVF method (p<0.05).

• Journal of Communications and Networks
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• v.12 no.5
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• pp.449-458
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• 2010

In this paper, we present a distributed resource allocation algorithm for multi-cell uplink systems that increases the weighted sum of the average data rates over the entire network under the average transmit power constraint of each mobile station. For the distributed operation, we arrange each base station (BS) to allocate the resource such that its own utility gets maximized in a noncooperative way. We define the utility such that it incorporates both the weighted sum of the average rates in each cell and the induced interference to other cells, which helps to instigate implicit cooperation among the cells. Since the data rates of different cells are coupled through inter-cell interferences, the resource allocation taken by each BS evolves over iterations. We establish that the resource allocation converges to a unique fixed point under reasonable assumptions. We demonstrate through computer simulations that the proposed algorithm can improve the weighted sum of the average rates substantially without requiring any coordination among the base stations.

• Journal of Environmental Science International
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• v.17 no.11
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• pp.1265-1271
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• 2008

Aerated submerged bio-film (ASBF) pilot plant has been developed. The presented studies optimized an inexpensive method of enhanced wastewater treatment. The objectives of this research were to describe pilot scale experiments for efficient removal of dissolved organic and nitrogen compounds by using ASBF reactor in plug-flow reactor (PFR) and improve understanding of dissolved organic matter and nitrogen compounds removal rates with dynamic relationships between heterotrophs and autotrophs in the fixed-film reactor. This research explores the possibility of enhancing the performance of shallow wastewater treatment lagoons through the addition of specially designed structures. This direct gas-phase contact should increase the oxygen transfer rate into the bio-film, as well as increase the micro-climate mixing of water, nutrients, and waste products into and out of the bio-film. This research also investigated the efficiency of dissolved organic matter and ammonia nitrogen removals in the ASBF. As it was anticipated, nitrification activity was highest during periods when the flow rate was lower, but it seemed to decline during times when the flow rate was highest. And ammonia nitrogen removal rates were more sensitive than dissolved organic matter removal rates when flow rates exceeded 2.2 L/min.

• Journal of environmental and Sanitary engineering
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• v.13 no.1
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• pp.185-194
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• 1998

Laboratory-scale investigation into initial anaerobic biofilm development was carried out by circulating mixed liquor from a steady-state anaerobic reactor through silicone tubing and then rerurning the mixed liquor to the reactor. The wall of the silicone tubing was the surface upon which anaerobic biofilm accumulation or development was monitored. Methanogenic bacteria accumulation was monitored by F$_{420}$ fluorescence (picomoles F$_{420}$/cm$^{2}$) of the extracted biofilm material. Biofilm accumulation was measured by the increase in COD of the extracted material ($\mu $g COD/cm$^{2}$). Experiments were conducted for 25 days, and biofilm analyses were performed at 5 days intervals. The results indicated that the initial rates of methangen and anaerobic biofilm accumulation increased with increasing organic loading rate and higher initial rates were observed for 15 days than 15 day liquid HRT or SRT. When the initial rates were plotted against the corresponding mixed liquor volatile suspended solids the difference between the results at the two HRT's became much less significant. Thus, the concentration of mixed liquor volatile suspended solids was found to be a very important parameter affecting initial anaerobic biofilm development. The ratio of methanogens to anaerobic biofilm was also investigated. The results showed that the ratio remained constant through the 25 days of each experiment and for high organic loading rates. Based on the results of this research, a reduction, a reduction of start-up period of anaerobic fixed film reactors might be achieved by maintaining a high organic loading and a large concentration of anaerobic microorganisms in the mixed liquor during the start-up period.

• Korea Journal of Hospital Management
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• v.11 no.3
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• pp.73-93
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• 2006

This study aims at providing necessary informations for management decision-making to the hospital manager, such as ratios of fixed and variable cost to total operating expense, and variable cost ratio to operating revenues, and determinant factors affecting cost behavior. A study model and related hypotheses were established, data were collected from 41 private university hospitals for the 6years from 1998 to 2003, and regression analyses were performed to test the hypotheses. The results of the analyses and conclusions are as follows; First, labor cost and administration cost within the same number of beds have not only fixed quality of the cost, but variable quality of that. Also, the ratio of the variable costs to operating revenue of the metropolitan was estimated 76.9% and that of other area hospitals was 80.1%. Second, the major factors affecting the increase rate of the operating expense were the increase rates of the number of inpatients, the number of employee, and the number of hospital operating bed. This result implies that maintaining a optimal hospital bed size and efficient operation of the beds are important strategic factors of hospital management.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.12 s.243
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• pp.1615-1620
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• 2005

We present a novel flow-rate independent cell counter using a fixed control volume between double electrical sensing zones. The previous device based on the single electrical cell sensing in a given flow-rate requires an accurate fluid volume measurement or precision flow rate control. The present cell counter, however, offers the flow-rate independent method for the cell concentration measurement with counting cells in a fixed control volume of $22.9{\pm}0.98{\mu}{\ell}$. In the experimental study, using the RBC (Red Blood Cell), we have compared the measured RBC concentrations from the fabricated devices with those from Hemacytometer. The previous and present devices show the maximum errors of $20.3\%\;and\;16.1\%$, which are in the measurement error range of Hemacytometer (about $20\%$). The present device also shows the flow-rate independent performance at the constant flow-rates ($5{\mu}{\ell}/min$ and $10{\mu}{\ell}/min$) and the varying flow-rate (4, 2, and $4{\mu}{\ell}/min$). Therefore, we demonstrate that the present cell counter is a simple and automated method for the cell concentration measurement without requiring an accurate fluid measurement and precision flow-rate control.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.80-83
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• 2010

This paper describes an analysis of decoding performance of multi-mode LDPC(Low Density Parity Check) decoder which supports three block lengths (648, 1296, 1944) and four code rates (1/2, 2/3,3/4, 5/6) for IEEE 802.11n WLAN system. A fixed-point model of LDPC decoder which adopts min-sum algorithm and layered decoding scheme is implemented using Matlab. From fixed-point simulation results for various bit-width parameters such as internal bit-width, bit-width of integer and fractional parts, an optimal design condition and decoding performance of LDPC decoder are analyzed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.432-438
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• 2011

This paper describes an analysis of optimal design conditions of multi-mode LDPC(low density parity check) decoder which supports three block lengths (648, 1296, 1944) and four code rates (1/2, 2/3, 3/4, 5/6) for IEEE 802.11n WLAN system. A fixed-point model of LDPC decoder, which adopts min-sum algorithm and layered decoding scheme, is implemented using Matlab. From fixed-point simulation results for various bit-width parameters such as internal bit-width, integer/fractional part bit-widths, optimal design conditions and decoding performance of LDPC decoder are analyzed.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.2
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• pp.135-142
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• 2023

Resin-bonded fixed partial denture (RBFPD)as known as Maryland bridge is is a well-known conservative method for its minimized invasion of the teeth for an anterior single tooth edentulous area. Despite of its various advantages, RBFPD was not widespread because of its high debonding rates, non-esthetic look or weak structure for material property. Currently, with the introduction of zirconia to dental material for RBFPD, Maryland bridge entered upon a new phase. Zirconia surmounts poor esthetics of metal framework, having proper strength, and overcomes ceramic's structural weakness, being sufficiently esthetic. In this case, edentulous area of maxillary left lateral incisor was restored using zirconia resin-bonded fixed partial denture. Restoration of missing tooth in anterior area was achieved using non-invasive and esthetic prosthesis, then we report this case as satisfactory results were obtained for both the operator and the patient.