• Korean Membrane Journal
• /
• v.7 no.1
• /
• pp.34-41
• /
• 2005

The wastewater discharged from a paper plant was filtrated by 3 kinds of tubular carbon ceramic UF and MF membranes with $N_2$-backflushing. The filtration time (FT) was fixed at 8 min or 16 min, and $N_2$-backflushing time (BT) was changed in 0${\~}$60 sec. The optimal condition was discussed in the viewpoints of total permeate volume ($V_T$), dimensionless permeate flux (J/Jo) and resistance of membrane fouling ($R_f$). In the viewpoints of $V_T$, J/Jo and $R_f$, the optimal $N_2$-BT was 40 sec at both FT for M9 (MWCO: 300,000 Daltons) and C005 ($0.05{\mu}m$) membranes. However, for C010 ($0.1{\mu}m$) it was 10 sec at FT=8 min, and 20 sec at FT=16 min in the viewpoints of J/Jo and $R_f$, and 5 sec at both FT in the viewpoints of $V_T$. It means that the short $N_2$-BT could reduce the membrane fouling and recover the permeate flux sufficiently for MF membrane having a large pore size as C010. Average rejection rates of pollutants were higher than $99.0\%$ for turbidity and $22.8{\~}59.6\%$ for $COD_{cr}$, but rejection rates of total dissolved solid (TDS) were lower than $8.9\%$. Therefore, the low turbidity water purified in our system could be reused for paper process.

• Journal of architectural history
• /
• v.2 no.2 s.4
• /
• pp.119-130
• /
• 1993

Berlage's importance in the history of the Modern Movements of Architecture lies in his effort to combine several sets of contradictory dual aspects of architectural values. Tradition and modernity are one of the contradictory dual aspects. For Berlage, tradtion and modernity were not tow opposing, but reconciliatory concepts. In this sense, Berlage thought that modernity did not mean a total rejection, but a reinterpretion of tradition. Berlage's concern with his contemporaty architectural situstion was how to revive the stagnant repetion of past styles in Historicism and, at same time, how to prevent an extreme rejection of tradition by the Avant-Gardists. Berlage's architectural belief that neither stagnant imitation of past styles nor extreme revolution can be an ideal model for his era, lies in a traditional art theory of 'style evolution' and the interpertation of Nature's lessons for it. This study is to understand Berlage's concept of 'style evolution' and the meaning of tradition and modernity in the early Modern Movements of Architecture.

• Proceedings of the KIPE Conference
• /
• 2019.11a
• /
• pp.7-9
• /
• 2019

이 논문은 이관성 시스템에서 능동 외란 제거 제어(Active Disturbance Rejection Control, ADRC) 기반의 진동 저감 알고리즘을 제안한다. 제안한 방법은 축소 차원 ADRC를 기반으로 구성하였다. ADRC 이론에 기반한 제어 이론은 전체 토크 중 전동기 측의 관성 모멘트에 대한 토크를 제외한 모든 토크를 외란 성분이라 설정한다. 외란에 대한 가속도 성분을 전체 외란(Total Disturbance)이라고 설정하고, 이를 추정하여 보상한다. 축소 차원 ADRC의 차수가 낮아서, 축소 차원 ADRC의 대역폭을 기존 ADRC의 대역폭보다 크게 설정할 수 있다. 그리고, 증가한 이득과 실질적인 구현을 고려하여, 이산 시간 영역에서 설계하였다. 제안된 알고리즘의 안정도를 확보하고, 성능을 높이기 위하여, 추정하는 제정수의 값을 실제 값보다 작게 설정하였다. 제안한 방법은 기계시스템의 공진에 의한 영향을 감쇄시킬 수 있다. 제안한 방법을 검증하기 위해, 시뮬레이션과 실험을 수행하였다.

• Membrane Journal
• /
• v.23 no.1
• /
• pp.92-99
• /
• 2013

In this study the nanofiltration (NF) membrane treatment of a sulfuric acid waste solutions containing copper ion ($Cu^{+2}$) discharging from the etching processes of the printed circuit board (PCB) manufacturing industry has been studied for the recycling of acid etching solution. SelRO MPS-34 4040 NF membrane from Koch company was tested to obtain the basic NF data for recycling of etching solution and separation efficiency (total rejection) of copper ion. NF experiments were carried out with a dead-end membrane filtration laboratory system. The pure water flux was increased with the increasing storage time in sulfuric acid solution and lowering pH of acid solution because of the enhancement of NF membrane damage by sulfuric acid. The permeate flux of acid solution was decreased with the increasing copper ion concentration. Total rejection of copper ion was decreased with the increasing storage time in sulfuric acid solution and copper ion concentration, and lowering the pH of acid solution. The total rejection of copper ion was decreased from initial 37% to 15% minimum value.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.9 no.7
• /
• pp.1607-1615
• /
• 2005

This Paper describes the implementation methods of MLP (mulilayer perceptrons) neural networks to recognize or reject handwritten numerals and non-nummerals. The MLP has known to be a very efficient classifier to recognize handwritten numerals in terms of recognition accuracy, speed, and memory requirements. In the previous researches, however, researchers have focused on the only numeral inputs and have not payed attention to the non-numeral inputs with respect to recognition accuracy, rejection rates, and other characteristics. In this paper, we present some implementation methods of the MLP in the environments that numeral and non-numerals are mixed. The MLPs have been developed by three methods, and investigated with three error types introduced. The experiments have been conducted on a total of 66,701 images of numerals and non-numerals. The promising method to recognize numerals and reject non-numerals has been described in terms of the three error types.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1384-1386
• /
• 2005

This paper focuses on development of load test simulator of a steam turbine-generator in a nuclear power plant. When load is taken off from electrical power network, it is very difficult to effectively control the steam flow to turbine of the nuclear turbine-generator, because of disturbances, such as electrical load and network unbalance on electrical network. Up to the present time, the conventional control system has been used for the load control on nuclear steam generator, owing to the easy control algorithms and the advantage which have been proven on the nuclear power plant. However, since there are problems with stability control during low power and start-up, only a highly experienced operator can operate during those procedures. Also, a great deal of time and an expensive simulator is needed for the training of an operator. The KEPRI is developed simulator for 600MW nuclear power plant to take a test of generator load rejection, throttle valve, and turbine load control. Total load test is implemented before start up.

• Korean Journal of Child Studies
• /
• v.34 no.2
• /
• pp.101-119
• /
• 2013

This study examined the relationship among preschoolers' temperament, parenting sense of competence, and mothers' parenting behavior. It also examined the mediating effects of parenting sense of competence on the relationship between preschoolers' temperament and mothers' parenting behavior. A total of 155 mothers with preschoolers aged 3 to 4(83 boys and 72 girls), living in Seoul, participated in this study. The mothers completed questionnaires designed to measure preschoolers' temperament, parenting sense of competence, and mothers' parenting behavior. The results indicated that preschoolers' temperament and mothers' parenting sense of competence were significantly related to warmth/acceptance and rejection/restriction. Additionally, preschoolers' temperament was significantly related to parental efficacy and dissatisfaction. Furthermore, parenting sense of competence mediated the relationship between preschoolers' temperament and mothers' parenting behavior. In particular, it was found that parental efficacy fully mediated the relationship between preschoolers' activity level and mothers' rejection/restriction. These findings imply that improving mothers' parenting sense of competence needs to be emphasized in designing prevention and intervention programs aimed at enhancing mothers' positive parenting behavior.

• Journal of Korean Society on Water Environment
• /
• v.28 no.5
• /
• pp.657-662
• /
• 2012

This study was carried out to evaluate the removal rate of organic and inorganic matters from landfill leachate using pre-treatment process as coagulation and limonite adsorption, and membrane process as RO (reverse osmosis) and NF(nanofiltration). By adding limonite adsorption as pre-treatment process, about 40% of organic matters in leachate was removed through pre-treatment process and 74.7% of boron was removed after RO process without pH adjustment. The rejection rate of boron in RO process mainly depends on the pH and increased at pH value of 10. RO process was performed as two stage system adjusting pH condtion to 7 and 10 in second RO stage for boron removal. Most (>90%) of TOC, Cl- and inorganic matters as Ca was rejected in first RO stage, the residue was rejected in second RO and the rejection rate was above 97%. Considering economic efficiency of operation cost, NF substituted for the first RO and total removal rate of TOC was above 90%. Through RO system toxicity to Daphnia in leachate was removed completely.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.59 no.2
• /
• pp.145-154
• /
• 2023

In this study, to control the heading angle of a ship, which is constantly subjected to various internal and external disturbances during the voyage, an LADRC (linear active disturbance rejection control) design that focuses more on improving the disturbance removal performance was proposed. The speed rate of change of the ship's heading angle due to the turn of the rudder angle was selected as a significant factor, and the nonlinear model of the ship's maneuvering equation, including the steering gear, was treated as a total disturbance. It is the similar process with an LADRC design for the first-order transfer function model. At this time, the gains of the controller included in LADRC and the gains of the extended state observer were tuned to RCGAs (real-coded genetic algorithms) to minimize the integral time-weighted absolute error as an evaluation function. The simulation was performed by applying the proposed GA-LADRC controller to the heading angle control of the Mariner class vessel. In particular, it was confirmed that the proposed controller satisfactorily maintains and follows the set course even when the disturbances such as nonlinearity, modelling error, uncertainty and noise of the measurement sensor are considered.

• Journal of Veterinary Clinics
• /
• v.40 no.6
• /
• pp.423-428
• /
• 2023

The mouse kidney transplantation model serves as an invaluable tool for exploring various aspects of the transplant process, including acute rejection, cellular and humoral rejection, ischemia-reperfusion injury, and the evaluation of novel therapeutic strategies. However, conducting venous anastomosis in this model poses a significant challenge due to the thin and pliable characteristics of the renal vein, which often obstruct clear visualization of the resected vein's edge. This study proposes the adoption of a two stay suture technique to enhance the visualization of the renal vein's edge, thereby facilitating efficient and successful venous anastomosis. A total of 22 mice served as kidney donors in this study. The conventional anchoring suture technique was employed for venous anastomosis in 11 of these mice, while the remaining 11 underwent the two stay suture technique. The anastomosis duration and completion rates were then compared between these two groups. The conventional anchoring suture technique yielded an average anastomosis time of 29 minutes and a completion rate of 64%. In contrast, the two stay suture technique demonstrated a substantial improvement, with an average anastomosis time of 14 minutes and a completion rate of 100%. The two stay suture technique offers a promising solution to enhance visualization during venous anastomosis in murine kidney transplantation. This technique may particularly benefit novices by enabling them to perform venous anastomosis more easily, swiftly, and successfully.