• Journal of the Korean Magnetics Society
• /
• v.2 no.2
• /
• pp.91-98
• /
• 1992

In a $Co_{67}Fe_{4.5}Nb_{2}Si_{10}B_{15}$ amorphous alloy ribbon the effect to two-step annealing on the soft magnetic properties has been studied. By two-step annealing method which the second annealing at low temperature of $310^{\circ}C$ for 2 hours is undertaken after the primary annealing at high temperature above $480^{\circ}C$ for 20 minutes at the vacuum state, the coercive force and the squareness are not changed nearly but the initial permeability at d.c. and the effective permeability at a.c. are remark-ably increased compared with the one-step annealing. The maxima of the initial permeability and the effective permeability at 1 kHz after the two-step annealing are 290,000 and 41,000, respectively, which are 30% higher than those of the one-step annealing. The change of magnetic properties with annealing temperature is discussed in terms of the residual stress, the domain size, the cluster and the crystalline phase.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.652-657
• /
• 2004

As the real-time multimedia applications through Internet increase, the bandwidth available to TCP connections is oppressed by the UDP traffic, result in the performance of overall system is extremely deteriorated. Therefore, developing a new transmission protocol is necessary. The TCP-friendly algorithm is an example meeting this necessity. The TCP-friendly (TFRC) is an UDP-based protocol that controls the transmission rate based on the available round transmission time (RTT) and the packet loss rate (PLR). In the data transmission processing, transmission rate is determined based on the conditions of the previous transmission period. If the one-step ahead predicted values of the control factors are available, the performance will be improved significantly. This paper proposes a prediction model of transmission rate control factors that will be used for the transmission rate control, which improves the performance of the networks. The model developed through this research is predicting one-step ahead variables of RTT and PLR. A multiplayer perceptron neural network is used as the prediction model and Levenberg-Marquardt algorithm is used for the training. The values of RTT and PLR were collected using TFRC protocol in the real system. The obtained prediction model is validated using new data set and the results show that the obtained model predicts the factors accurately.

• Journal of the Society of Naval Architects of Korea
• /
• v.40 no.5
• /
• pp.43-52
• /
• 2003

Two methods which estimate manoeuvring derivatives in the model of hydrodynamic force and moment acting on a manoeuvring ship using sea trial data were compared. One is the widely used parameter estimation method by using the Extended Kalman Filter (EKF), which estimates state variables of linearized state space model at every instant after dealing with the coefficients as the augmented state variables. The other one is the Estimation-Before-Modeling (EBM) technique, so called the two-step method. In the first step, hydrodynamic force of which dynamic model is assumed the third-order Gauss-Markov process is estimated along with motion variables by the EKF and the modified Bryson-Frazier smoother. Then, in the next step, manoeuvring derivatives are identified through the regression analysis. If the exact structure of hydrodynamic force could be known, which was an ideal case, the EKF method would be regarded as being more superior compared to the EBM technique. However the EBM technique was more robust than the EKF method from a realistic point of view where the assumed model structure was slightly different from the real one.

• Structural Engineering and Mechanics
• /
• v.63 no.1
• /
• pp.77-88
• /
• 2017

Correction Factor Method (CFM) is one of the earliest methods for simulating the actual behavior of structure according to construction sequences and practical implementation steps of the construction process which corrects the results of the conventional analysis just by the application of correction factors. The most important advantages of CFM are the simplicity and time-efficiency of the computations in estimating the final modified forces of the beams. However, considerable inaccuracy in evaluating the internal forces of the other structural members obtained by the moment equilibrium equation in the connection joints is the biggest disadvantage of the method. This paper proposes a novel method to eliminate the aforementioned defect of CFM by using the column shortening correction factors of the CFM to modify the axial stiffness of columns. In this method, the effects of construction sequences are considered by performing a single step analysis which is more time-efficient when compared to the staged analysis especially in tall buildings with higher number of elements. In order to validate the proposed method, three structures with different properties are chosen and their behaviors are investigated by application of all four methods of: conventional one-step analysis, sequential construction analysis (SCA), CFM, and currently proposed method.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.4
• /
• pp.759-764
• /
• 2009

In this paper designed One-Step mobile shopping system using Multipurpose Visual Language System(MVLS). MVLS is based on braille system, and list this to a square color box. This is can accomplish convenience of use and encipherment of fundamental personal information. Also, this system has advantage to fast communication speed because that has little size packets. Planed system does and fit this in shopping to graft together mobile-phone that the such MVLS and most of internal adult are possessing. User can more fast finish shopping just photographing and press the button that show on TV or PC monitor and printed materials etc. by camera of mobile phone.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.26 no.6
• /
• pp.71-78
• /
• 1989

The imput-output relations for nonlinear systems can be explicitly represented by the Volterra series and they can be characterized by the Volterra kernels. This study is concerned with modeling an elastomer force-displacement relation due to step inputs by utilizing the truncated Volterra series. Since it is practically impossible to apply step inputs that have infinite slope at zero time, the loads due to constant penetration(displacement) rate followed by constant penetration inputs are measured as an alternative approach and estimated for step inputs and then utilized for the truncated Volterra series models. One second order and one third order truncated Volterra series models have been employed to model the force-displacement relation which is one of the prominent properties to characterize the viscoelastic material. The third order truncated Volterra series model has better results, compared with those of the second order truncated Volterra series model.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.24 no.3
• /
• pp.96-104
• /
• 1998

It was possible to produce W/O/W one step multiple emulsion on the system which satisfied following conditions. 1. 1-5％ of hydrophilic liquid surfactant over HLB20 and lipophilic liquid surfactant which has HLB 3∼5 2. Non wax copolymers as oil thickener 3. More than 0.5％ of carbomer as aqueous thickener 4. The manufacturing process which neutralize the dispersed carbomer (2.0％ in water), after emulsifying. For the selective addition into inner and outer aqueous phase, we melted the glucose in water before emulsifying. Using an Anthrone analysis method, we analyzed the encapsulation yield of glucose in inner water phase. It was possible to raise the water encapsulation yield of the multiple emulsion through the following conditions. 1. Using of anionic hydrophilic surfactant(HLB 40) and lipophilic surfactant (HLB 3∼5) 2. Controlling the ratio of hydrophilic surfactant and lipophilic surfactant 3. Strengthening interface with increase of non wax oil thickener. When the separated adding process of glucose was adopted, approximately 85％ of glucose was added selectively within inner aqueous phase.

• Journal of Institute of Control, Robotics and Systems
• /
• v.11 no.4
• /
• pp.385-391
• /
• 2005

As the Internet real-time multimedia applications increases, the bandwidth available to TCP connections is oppressed by the UDP traffic, result in the performance of overall system is extremely deteriorated. Therefore, developing a new transmission protocol is necessary. The TCP-friendly algorithm is an example satisfying this necessity. The TCP-Friendly Rate Control (TFRC) is an UDP-based protocol that controls the transmission rate that is based on the available round trip time (RTT) and the packet loss rate (PLR). In the data transmission processing, transmission rate is determined based on the conditions of the previous transmission period. If the one-step ahead predicted values of the control factors are available, the performance will be improved significantly. This paper proposes a prediction model of transmission rate control factors that will be used in the transmission rate control, which improves the performance of the networks. The model developed through this research is predicting one-step ahead variables of RTT and PLR. A multiplayer perceptron neural network is used as the prediction model and Levenberg-Marquardt algorithm is used for the training. The values of RTT and PLR were collected using TFRC protocol in the real system. The obtained prediction model is validated using new data set and the results show that the obtained model predicts the factors accurately.

• Korean Membrane Journal
• /
• v.3 no.1
• /
• pp.9-16
• /
• 2001

The diamide-diamine having carboxylic acid was prepared by direct condensation of 1,2,4-benzenetricarboxylic acid with bits[4- (3-aminophenoxy ) phenyl] sulfone and bits(4-aminouhenyl)-1,4- diisopropylbenzene in medium consisting of triphenylphosphite, LiCl, and N-methyl-2-pyrrolidone. Copoly (amide-imide) derivatives with high molecular weight could be synthesized by one-step polycondensation of prepared diamide-diamine having carboxylic acid and various dianhydride compounds. Depending on the chemical structure and composition of polymer backbones, the viscosities of polymers were found to range between 0.87∼ 1.57 dL/B. All the polymers showed good thermal stability up to 320$\^{C}$ and the 10% weight loss temperature was observed in the range of 450∼540$\^{C}$ in a thermogravimetric traces. The glass transition was recorded in the temperature range of 200 ∼ 270$\^{C}$. All the polymers showed an amorphous nature on a differential scanning calorimetric thermograms. These polymers generally had good mechanical properties and readily soluble in various polar solvents. Further, it was proved that their properties could be determined from the composition.

• Nuclear Engineering and Technology
• /
• v.51 no.5
• /
• pp.1209-1217
• /
• 2019

Due to the limitation of the computers, the conventional homogenization method is based on many assumptions and approximations, and some tough problems such as energy spectrum and boundary condition are faced. To deal with those problems, the Monte Carlo global homogenization is adopted. The Reactor Monte Carlo code RMC is used to study the global homogenization method, and the one-step global homogenization method is proposed. The superimposed mesh geometry is also used to divide the physical models, leading to better geometric flexibility. A set of multigroup homogenization cross sections is online generated for each mesh under the real neutron energy spectrum and boundary condition, the cross sections are adjusted by the superhomogenization method, and no leakage correction is required. During the process of superhomogenization, the author-developed reactor core program NLSP3 is used for global calculation, so the global flux distribution and equivalent homogenization cross sections could be solved simultaneously. Meanwhile, the calculated homogenization cross section could accurately reconstruct the non-homogenization flux distribution and could also be used for fine calculation. This one-step global homogenization method was tested by a PWR assembly and a small reactor model, and the results show the validity.