• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.939-947
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• 2010

The LDPC(Low-Density Parity-Check) code, which is one of the channel encoding methods in IEEE 802.11n wireless LAN standard, has superior error-correcting capabilities. Since the hardware complexity of LDPC decoder is high, it is very important to take into account the trade-offs between hardware complexity and decoding performance. In this paper, the effects of LLR(Log-Likelihood Ratio) approximation on the performance of MSA(Min-Sum Algorithm)-based LDPC decoder are analyzed, and some optimal design conditions are derived. The parity check matrix with block length of 1,944 bits and code rate of 1/2 in IEEE 802.11n WLAN standard is used. In the case of $BER=10^{-3}$, the $E_b/N_o$ difference between LLR bit-widths (6,4) and (7,5) is 0.62 dB, and $E_b/N_o$ difference for iteration cycles 6 and 7 is 0.3 dB. The simulation results show that optimal BER performance can be achieved by LLR bit-width of (7,5) and iteration cycle of 7.

• Journal of Chest Surgery
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• v.33 no.8
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• pp.648-654
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• 2000

Background: Cardiopulmonary bypass during open heart surgery causes systemic inflammatory respose. IL-10 is an anti-inflammatory cytokine that inhibits inflammatory process and protects organ function by down regulation of pro-inflammatory cytokine release and maintenance of blood level balance with pro-inflammatory cytokines. Mateial and Method: Plasma IL-10 levels were measured and analyzed in 22 patients who underwent open heart surgery (11 cases of coronary artery bypass graft, 11 cases of valve replacement) under cardiopulmonary bypass since 1988 January to July at Department of Thoracic and Czardiovascular surgery, Yeungnam University Hospital. 1g of methylprednisolone was administrated to thirteen patients randomly. Blood samp.es were taken and collected at the time of induction of anesthesia, 10 min before cardiopulmonary bypass, 10 min after starting of CPB, 10 min aftr aortic cross clamping, 10 min after ACC release, and 10 min, 2 hours, and `5 hours after CPB respectively. The plasma levels of IL-10 were determined by enzyme-linked immunosorbent assays(ELISA). Wilcoxon-Raule Sum test was used for statistical analysis. Result: In all 22 patients, cardiopulmonary bypass time was used for statistical analysis. Result: In all 22 patients, cardiopulmonary bypass time was 171$\pm$41.4 min and aortic cross clamp time was 118$\pm$36.5 min. Peak IL-10 level was achieved at 10 min after ACC(361.0$\pm$52.81pg/ml) and was decreased sharply at 2 hours after CPB. Peak IL-10 level was correlated positively with aortic cross clamp time(p=0.011); however, it did not correlated with bypass time(p=0.181). In valve replacement group, mean IL-10 level at peak point was 567.89$\pm$107.69 pg/ml and was significantly higher than that of coronary artery bypass group(205.67$\pm$192.70 pg/ml)(p<0.001). ACC time in valve replacement group was significantly longer than that of coronary artery bypass group(p<0.01), however, bypass time was not(p=0.212). Thirteen patients with steroid pretreatment before starting of CPB showed relatively higher plasma IL-10 level than in control group, however, no statistical significance was noted(p=0.19). Conclusion: plasma level of IL-10 was increased in association with cardiopulmonary bypass and revealed peak at 10 min after ACC release. IL-10 level was correlated positively with ACC time. Therefore, systemic inflammatory respeonse in association with cardiopulmonary bypass could be decreased by reducing ACC time during cardiac surgery.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.8
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• pp.1593-1598
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• 2012

In this paper, we propose an intelligent signal control method based on fuzzy logic applicable in real time. We design membership functions to model occupied time and the number of vehicles for each lane. A priority for each signal phase is computed by the popular Max-Min fuzzy inference based on control rules and membership degrees of prepared two functions at any given time. A tie breaking scheme is considering weighted sum of the rate of occupied time per number of vehicles in that block and the standard deviation of these blocks. Only a signal phase with the highest priority is opened and all others are closed and the duration of the phase opening is computed proportional to the rate of number of weighting vehicles in that signal per all weighted vehicles. The simulation result shows that the proposed method is more efficient than the static control in all simulation conditions in $2{\times}3$ experimental designs with the number of vehicles in intersection and congestion degrees that have all three levels.

• Journal of Embryo Transfer
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• v.14 no.2
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• pp.131-137
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• 1999

This experiment was carried out to investigate the effects of osmolarity of thawing diluents, seminal plasma added in thawing diluents on the sperm viability and the effects of thawing temperature, the temparature of the thawing diluents on the sperm viability and acrosomal morphology of boar spermatozoa by the straw method. The result obtained were summarized as follows: 1. The sperm viablilty after thawing of the frozen semen was shown greater in the high osmolarity(392~492mOsm) than low osmolarity(300mOsm) in thawing diluent. The added levels of seminal plasma in thawing diluent did not affect the viability of frozen-thawed boar semen. 2. In terms of thawing temperature, the sperm viability was shown higher in the frozen semen thawed at 5$0^{\circ}C$ for one min. (p<0.01) than those thawed at 2$0^{\circ}C$ or 37$^{\circ}C$ for one min. The sperm viability was not significant at the diluent temparature of 2$0^{\circ}C$or 37$^{\circ}C$ after thawing: but the sperm viability was higher in thawing diluent at 2$0^{\circ}C$ than in that at 37$^{\circ}C$. However, the effects of thawing temperature and diluent solution on normal acrosomal rate were not significant. 3. Cleavage rates of oocytes fertilized with frozen semen were 46.4% and 43.3%, respectively, which were thawed at 5$0^{\circ}C$ for one min. and then diluted in mBTS medium at 2$0^{\circ}C$or 37$^{\circ}C$. To sum up, the sperm viability was shown greater at the high of thawing diluents of frozen boar semen. In terms of thawing conditions, the sperm viability was shown greater, when semen was thawed at a high temperature for a short time and then diluted at the same temperature as that in the straw.

• Journal of Preventive Medicine and Public Health
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• v.23 no.3 s.31
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• pp.358-368
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• 1990

To investigate the possibility of utilizing of sister chromatid exchange(SCE) analysis in lymphocytes as an indicator which could evaluate the effects of mutagenicity after in vivo exposure to hexavalent chromium, this study was conducted using some of chromium plating workers occupationally exposed to hexavalent chromium, chromium trioxide ($CrO_3$) in Taegu city. The study population was 12 Cr platers with perforation of nasal septum, 12 Cr platers without perforation of nasal septum and 20 controls. The SCE in peripheral blood lymphocytes of the subjects was analyzed and blood chromium concentration was estimated using the atomic absorption spectrophotometer (IL551) equipped with furnace atomizer (IL755). The mean SCE frequencies for Cr platers with and without perforation of nasal septum were statistically higher than those for control. The difference in SCE frequencies by age, smoking habits were not statistically significant both in Cr platers and controls. There was no difference in SCE frequencies by career of Cr platers workers. In Cr platers, the correlation between the mean SCE frequencies and chromium concentration in blood was not statistically significant. Using the transformation $y=(sum\;SCE)^{\frac{1}{2}}+(sum\;SCE+1)^{\frac{1}{2}}$, when the data was studied by multiple regression, it appeared that the influence of the occupation was the most important. Age, smoking, occupation and CrB(blood chromium concentration) together explain only 32.3% of interpersonal variation on SCE. The results in this study suggest tt a genetic risk due to occupationally exposure to hexavalent chromium is clearly inferable and thus, SCE analysis in human lymphocytes may be used indicator of biological toxic effects of chromium. Further, populatio analysis stuies are required before SCE frequency can be used as a mutagenic indicator in human population.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.243-250
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• 2014

In this paper, I devise a balance-swap optimization (BSO) algorithm to solve economic load dispatch with a quadratic fuel cost function. This algorithm firstly sets initial values to $P_i{\leftarrow}P_i^{max}$, (${\Sigma}P_i^{max}$ > $P_d$) and subsequently entails two major processes: a balance process whereby a generator's power i of $_{max}\{F(P_i)-F(P_i-{\alpha})\}$, ${\alpha}=_{min}(P_i-P_i^{min})$ is balanced by $P_i{\leftarrow}P_i-{\alpha}$ until ${\Sigma}P_i=P_d$; and a swap process whereby $_{max}\{F(P_i)-F(P_i-{\beta})\}$ > $_{min}\{F(P_i+{{\beta})-F(P_j)\}$, $i{\neq}j$, ${\beta}$ = 1.0, 0.1, 0.1, 0.01, 0.001 is set at $P_i{\leftarrow}P_i-{\beta}$, $P_j{\leftarrow}P_j+{\beta}$. When applied to 15, 20, and 38-generators benchmark data, this simple algorithm has proven to consistently yield the best possible results. Moreover, this algorithm has dramatically reduced the costs for a centralized operation of 73-generators - a sum of the three benchmark cases - which could otherwise have been impossible for independent operations.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.79-85
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• 2006

Radiative heat transfer is very important in many combustion systems since they are operated in high temperature. Fluid flows in most of the combustion systems are turbulent to promote fast mixing of the hydrocarbon fuel and oxidant. Major combustion products are $CO_2$ and $H_2O$. The turbulent flow is modeled by using the standard ${\kappa}-{\epsilon}$ model and the radiation transfer is modeled by using the discrete ordinates method where the radiative gas properties are calculated by using the weighted sum of gray gases model with a gray gas regrouping(WSGGM-RG). Effect of the radiation on the combustion characteristics in a three-dimensional rectangular enclosure is studied by changing the equivalence ratio. Results show that the radiation plays a significant role on the heat transfer in the combustion systems by resulting in a temperature drop of 16% as compared to that obtained without radiation. The equivalence ratio also affects the combustion by different contribution of the radiative transfer with different gas compositions.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.2
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• pp.126-131
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• 2010

Objectives: This study is aimed to determine any differences in the postoperative stability between absorbable and titanium plate systems for fixation in orthognathic surgery with simultaneous maxillomandibular procedures especially including maxillary posterior impaction and advancement. Study Design: Forty patients with dentofacial deformities were randomly assigned into titanium (4 males and 6 females) and absorbable (17 males and 13 females) fixation group. All patients had undergone surgical alterations of maxilla with posterior impaction and advancement. A comparison study of the change in the maxillary position after the simultaneous surgery was performed with 1-day, 6-months postoperative lateral cephalograms compared to preoperative lateral cephalogram by tracing. Wilcoxon rank sum test was used for statistical analysis. Result: The position of the maxilla was stable after surgery and was not changed significantly from 1 day to 6 month after the simultaneous maxillomandibular surgery both in the experimental (absorbable plates) and control (titanium plates). Conclusion: This study suggests that application of absorable plating system in the fixation of maxillary segment in the simultaneous maxillomandibular procedures, leads to a predictable short-term postoperative skeletal stability comparable to the titanium plating system. Long term follow-up and further studies will be needed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.4
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• pp.425-434
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• 2010

This study presents the alternative evaluation technique for the high-rise building structural system. The alternative evaluation of the structural system is performed in three steps, that is, preliminary evaluation, main evaluation and detailed evaluation. The evaluation categories are composed of structural performance, economic feasibility and term of work. Each categories are composed of detailed items to evaluate of its own. In preliminary evaluation, qualitative evaluation based on experimental knowledge is performed. In main and detailed evaluations, quantitative evaluations based on numeric data are performed. The weighted-sum method is applied to integrate the evaluated results of each items and its importance. The applicability of the proposed method was verified by applying it to the practical buildings and simulate the procedures.

• Journal of the Korea Society of Computer and Information
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• v.23 no.8
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• pp.133-142
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• 2018

Subway metro scheduling is one of the most important problems impacting passenger convenience today. To operate efficiently, the Seoul metro uses regular, periodic schedules for all lanes, both north and southbound. However, many past studies suggest that non-periodic scheduling would better optimize costs. Since the Seoul metro is continuously facing a deficit, adopting a non-periodic schedule may be necessary. Two objectives are presented; the first, to minimize the average passengers' waiting time, and the second, to minimize total costs, the sum of the passenger waiting time, and the operational costs. In this paper, we use passenger smart card data and a precise estimation of transfer times. To find the optimal time-table, a genetic algorithm is used to find the best solution for both objectives. Using Python 3.5 for the analysis, for the first objective, we are able to reduce the average waiting time, even when there are fewer trains. For the second objective, we are able to save about 4.5 thousand USD with six fewer trains.