• Korean Membrane Journal
• /
• v.11 no.1
• /
• pp.15-20
• /
• 2009

The periodic water-back-flushing using permeate water was performed to minimize membrane fouling and to enhance permeate flux in tubular ceramic ultrafiltration (UF) system for Gongji stream water treatment in Chuncheon city. The filtration time (FT), which was the water-back-flushing period, 2 min with periodic 15 sec water-back-flushing showed the highest value of dimensionless permeate flux ($J/J_o$), and the lowest value of resistance of membrane fouling ($R_f$), and we acquired the highest total permeate volume ($V_T$) of 6.35 L. Consequently FT 2 min at back-flushing time (BT) 15 sec could be the optimal condition in advanced UF water treatment of Gongji stream. Then the average rejection rates of pollutants by our tubular ceramic UF system were 99.4% for Turbidity, 31.8% for $COD_{Mn}$, 22.6% for $NH_3$-N and 65.9% for T-P.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.3 no.2
• /
• pp.127-135
• /
• 1983

A new approach is developed to analyze the reliability of the earth retaining wall using the concept of probability of failure, instead of conventional factor of safety. Many uncertainties, which are included in the conventional stability analysis, can be excluded by using the stochastic approach. And the reliability, more consistent with the reality, can be obtained by the simulation. The strength parameters of soil properties are assumed to be random variables to follow a generalized beta distribution. The interval [A, B] of the random variables could be determined using the maximum likelihood estimation. The pseudo-random values corresponding to the proposed beta distribution are generated using the rejection method. The probability of failure defined as follows, is obtained by using the Monte Carlo Method. $$P_f=\frac{M}{N}$$ where, $P_f$ : Probability of failure N : Total number of trials M : Total number of failure out of N A computer program is developed for the computation procedure mentioned above. Finally, a numerical example is solved using the developed program.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.4 no.3
• /
• pp.75-83
• /
• 1984

The probability of failure is used to analyze the reliability of three dimensional slope failure, instead of conventional factor of safety. The strength parameters are assumed to be normal variated and beta variated. These are interval estimated under the specified confidence level and maximum likelihood estimation. The pseudonormal and beta random variables are generated using the uniform probability transformation method according to central limit theorem and rejection method. By means of a Monte-Carlo Simulation, the probability of failure is defined as; $P_f=M/N$ N: Total number of trials M: Total number of failures Some of the conclusions derived. from the case study include; 1. Three dimensional factors of safety are generally much higher than 2-D factors of safety. However situations appear to exist where the 3-D factor of safety can be lower than the 2-D factor of safety. 2. The $F_3/F_2$ ratio appears to be quite sensitive to c and ${\phi}$ and to the shape of the 3-D shear surface and the slope but not to be to the unit weight of soil. 3. From the two models (normal, beta) considered for the distribution of the factor of safety, the beta distribution generally provides lager than normal distribution. 4. Results obtained using the beta and normal models are presented in a nomgraph relating slope height and slop angle to probability of failure.

• Radiation Oncology Journal
• /
• v.30 no.4
• /
• pp.165-172
• /
• 2012

Purpose: To retrospectively evaluate the outcome and toxicity of total lymphoid irradiation (TLI) based conditioning regimen for allogeneic hematopoietic stem cell transplantation (HSCT) in severe aplastic anemia (SAA) patients who experienced an engraftment failure from prior HSCT or were heavily transfused. Materials and Methods: Between 1995 and 2006, 20 SAA patients received TLI for conditioning of HSCT. All patients were multi-transfused or had long duration of disease. Fifteen (75%) patients had graft failure from prior HSCT. In 18 (90%) patients, the donors were human leukocyte antigen identical siblings. The stem cell source was the peripheral blood stem cell in 15 (75%) patients. The conditioning regimen was composed of antithymocyte globulin plus TLI with a median dose of 750 cGy in 1 fraction. The graft-versus-host disease (GVHD) prophylaxis used cyclosporine with methotrexate. Results: With a median follow-up of 10.8 years, graft failures developed in 6 patients. Among them, 3 patients received their third HSCT to be engrafted finally. The Kaplan-Meier overall survival rate was 85.0% and 83.1% at 5 and 10 years, respectively. The incidence of acute and chronic GVHD was 20% and 20%, respectively. None of the patients have developed a malignancy after HSCT. Conclusion: In our study, TLI based conditioning in allogeneic HSCT was feasible with acceptable rates of GVHD in SAA patients who experienced graft failure from prior HSCT or was at a high risk of graft rejection. We achieved relatively better results of engraftment and survival with a long term follow-up.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.18 no.10
• /
• pp.997-1005
• /
• 2008

Linear motor stage is a useful device in precision engineering field because of its simple power transmission mechanism and accurate positioning. Even though linear motor stage shows fine positioning accuracy along travel axis, geometric dependent errors which relay on machining and assembling accuracy should be addressed to increase total positioning performances. In this paper, we suggests a cost effective yaw error compensation servo-system which is mounted on platform of the stage and nullify travel position dependent yaw error. This paper also provides a method of designing a sliding mode control which is robust to existing friction disturbance and model uncertainties. The reachability condition of slinding mode control for the yaw error compensating servo-system has been established. From some experimental results by using an experimental set-up, the sliding mode control showed its effective in disturbance rejection and its performance was superior to conventional linear controls.

• Korean Journal of Child Studies
• /
• v.32 no.4
• /
• pp.203-216
• /
• 2011

The purpose of this study was to investigate the relationships between mothers' parental intelligence and children's abilities of self-control and empathy. 180 children aged 5 were selected from 4 kindergartens in G city. The gender breakdown for the sample group was as follows : boys comprised 60.0% (108) and girls comprised 40.0% (72) of the total sample. The Parental Intelligence Scales (PIS) was used to rate mothers' parental intelligence. Children's self-control and empathy were also measured. The SPSS 12.0 program was used for the purposes of analyzing the data. The results of the study were as follows. Firstly, mothers' parental intelligence was related in a general sense with children's self-control. However, such a relationship did not appear between rejection in the area of parental intelligence and self appraisal in self-control, nor did it appear between acceptance in intelligence and emotion in self-control. Secondly, the variable of encouragement was the only one in evidence in terms of mothers' parental intelligence and how it was related with children's empathy.

• Journal of Korean Society of Water and Wastewater
• /
• v.14 no.3
• /
• pp.224-230
• /
• 2000

Membrane processes are capable of removing much materials from water. The removal or rejection characteristics of a membrane is usually depend upon the nominal pore size or MWCO(molecular weight cut off). A membrane with a smaller nominal pore size or MWCO should be capable of removing smaller contaminants from water. A series of experiments was performed to investigate the separation characteristics of membrane processes which consisted of microfiltration(MF) and nanofiltration(NF). To evaluate removal efficiencies of some pollutants such as the consumption of $KMnO_4$, THMFP, NH3-N, Fe, Mn, and pesticides, source water sampled from the Kum river was treated by the those membrane processes. Also, the results of experiments were compared with those of conventional water treatment processes. By two types of the membrane process, total removal efficiency of $KMnO_4$ consumed, THMEP, and $NH_3-N$ were 91.0%, 84.3%, and 85.5%, respectively and those processes were efficient in pesticides removal as well. Most of the effluents satisfied the Korean standard of drinking water quality continuously in the experimental periods. However, NF was needed for producing the safe drinking water in case of treating the raw water contaminated with Mn since removal efficiency of MF was not high enough. On the basis of the experimental results, it was suggested that NF could be applied to remove not only $NH_3-N$ but THMFP even without pre-chlorination.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.33 no.2
• /
• pp.144-148
• /
• 2011

Purpose: The purpose of this study was to evaluate the effectiveness of a novel bone grafting material using an autogeneous tooth (AutoBT) and provide the basis for its clinical application. The AutoBT contains organic and inorganic mineral components and is prepared from autogenous grafting material, thus eliminating the risk of immune reactions that may lead to its rejection. AutoBT can be used as bone material as is has both osteoinduction and osteoconduction activities at guided bone regeneration for implant placement and maxillary sinus graft. Methods: In a total of 63 patients, guided bone regeneration surgery was performed at the time of implant placement, and tissue samples were harvested at the time of the second surgery with the patient's consent. Results: There were no complications in guided bone regeneration using autogeneous tooth. Conclusion: We concluded that AutoBT underwent gradual resorption and was replaced by new bone of excellent quality via osteoinduction and osteoconduction.

• Journal of Chest Surgery
• /
• v.30 no.5
• /
• pp.537-539
• /
• 1997

An orthotopic cardiac transplantation was successfully performed in a 40 year-old Jehovah's witness without use of any blood product. Preoperatively, the patient had been on coumadin to prevent left atrial thrombi and the INR(Internation Normalized Ratio)of prothrombin titre was 2.4. During the operation, cell saver was used for shed blood and aprotinin was admini tered intravenously for platelet function. Total postoperative drainage was 860cc and the lowest hemoglobin was 12.2 gmldl. Postoperative course was complicated by central nervous system infection by wisteria monocytogenes and two episodes of rejection, both of which were effectively treated. The patient is on his 5th postoperative month and doing well.

• The Journal of the Acoustical Society of Korea
• /
• v.18 no.1
• /
• pp.86-91
• /
• 1999

This paper presents the text-prompt method to overcome the weakness of text-dependent and text-independent speaker recognition. Enhanced dynamic time warping for speaker recognition algorithm is applied. For the real-time processing, we use a simple algorithm for end-point detection without increasing computational complexity. The test shows that the weighted-cepstrum is most proper for speaker recognition among various speech parameters. As the experimental results of the proposed algorithm for three prompt words, the speaker identification error rate is 0.02%, and when the threshold is set properly, false rejection rate is 1.89%, false acceptance rate is 0.77% and verification total error rate is 0.97% for speaker verification.