• Korean Journal of Materials Research
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• v.22 no.12
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• pp.675-681
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• 2012

We aimed to examine the co-doping effects of 1/6 mol% $Mn_3O_4$ and 1/4 mol% $Cr_2O_3$ (Mn:Cr = 1:1) on the reaction, microstructure, and electrical properties, such as the bulk defects and grain boundary properties, of ZnO-$Bi_2O_3-Sb_2O_3$ (ZBS; Sb/Bi = 0.5, 1.0, and 2.0) varistors. The sintering and electrical properties of Mn,Cr-doped ZBS, ZBS(MnCr) varistors were controlled using the Sb/Bi ratio. Pyrochlore ($Zn_2Bi_3Sb_3O_{14}$), ${\alpha}$-spinel ($Zn_7Sb_2O_{12}$), and ${\delta}-Bi_2O_3$ (also ${\beta}-Bi_2O_3$ at Sb/Bi ${\leq}$ 1.0) were detected for all of the systems. Mn and Cr are involved in the development of each phase. Pyrochlore was decomposed and promoted densification at lower temperature on heating in Sb/Bi = 1.0 system by Mn rather than Cr doping. A more homogeneous microstructure was obtained in all systems affected by ${\alpha}$-spinel. In ZBS(MnCr), the varistor characteristics were improved dramatically (non-linear coefficient, ${\alpha}$ = 40~78), and seemed to form ${V_o}^{\cdot}$(0.33 eV) as a dominant defect. From impedance and modulus spectroscopy, the grain boundaries can be seen to have divided into two types, i.e. one is tentatively assigned to ZnO/$Bi_2O_3$ (Mn,Cr)/ZnO (0.64~1.1 eV) and the other is assigned to the ZnO/ZnO (1.0~1.3 eV) homojunction.

• Journal of the Korea Concrete Institute
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• v.23 no.5
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• pp.617-626
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• 2011

Seven post-tensioned lightweight concrete (LWC) beam specimens were tested under a symmetrical two-point top loading system. The parameters investigated were the amounts of mild longitudinal reinforcement and effective prestressing. The design compressive strength and dry density of the LWC tested were 30 MPa and 1,770 $kg/m^3$, respectively. Similar to post-tensioned normal weight concrete (NWC) beams, the crack propagation and stress increase of the unbonded tendons were significantly affected by the amounts of mild longitudinal reinforcement and effective prestressing. With the increase in the amounts of mild longitudinal reinforcement and effective prestressing, the serviceability and flexural capacity of the beams were enhanced whereas the stress increase in the unbonded tendons decreased. To control the crack width in post-tensioned LWC beams, a minimum amount of mild longitudinal reinforcement specified in ACI 318-08 provision is required. The flexural behavior of post-tensioned LWC beams and stress increase of the unbonded tendons could be rationally predicted by the proposed non-linear two-dimensional analysis. On the other hand, ACI 318-08 flexure provision was too conservative about the post-tensioned LWC beams.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.269-272
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• 2015

this is the study of the human body antenna device which can detect the powder in a 360-degree on(under) the ground whether it is metal or nonmetal using superhigh frequency RF beam equipped with the body. and it is able to transmit the data of the detection of the powder, battle combats can share that among them. with its flexible roof radial antenna structure, it emits the superhigh frequency RF beam to the front and flank multiply, preprocesses through the powder preprocessing part. and with the non-linear regression model algorism engine part, reflecting the attenuation characteristics depend on the delayed time of degree of the signal power which is received to the superhigh frequency RF beam. so it is able to detect the signal of the most likely mine or powder based on the degree of the answer signal power according to the delayed time of the superhigh frequency RF beam. also, it can detect the powder whether it is metal or nonmetal, mine, dud, VBIED. it can increase the chance of detection about 90% more than existing mine detector.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.8
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• pp.96-105
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• 1998

The aim of this paper is to propose the method of WDHMM(Weighted DHMM), using the MLP-VQ for the improvement of speaker-independent connect-digit recognition system. MLP neural-network output distribution shows a probability distribution that presents the degree of similarity between each pattern by the non-linear mapping among the input patterns and learning patterns. MLP-VQ is proposed in this paper. It generates codewords by using the output node index which can reach the highest level within MLP neural-network output distribution. Different from the old VQ, the true characteristics of this new MLP-VQ lie in that the degree of similarity between present input patterns and each learned class pattern could be reflected for the recognition model. WDHMM is also proposed. It can use the MLP neural-network output distribution as the way of weighing the symbol generation probability of DHMMs. This newly-suggested method could shorten the time of HMM parameter estimation and recognition. The reason is that it is not necessary to regard symbol generation probability as multi-dimensional normal distribution, as opposed to the old SCHMM. This could also improve the recognition ability by 14.7% higher than DHMM, owing to the increase of small caculation amount. Because it can reflect phone class relations to the recognition model. The result of my research shows that speaker-independent connected-digit recognition, using MLP-VQ and WDHMM, is 84.22%.

• Development and Reproduction
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• v.20 no.4
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• pp.331-347
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• 2016

Sexual dimorphism is the most conspicuous difference between the sexes. This study examines possible sexual dimorphism and the relative growth patterns of morphometric characteristics in the marine medaka, Oryzias dancena for their potential to help differentiate between males and females of this species. The von Bertalanffy growth parameters estimated by a non-linear regression method were $L_{\infty}=30.2mm$, K=3.22/year, and ${\tau}_0=-0.05$. All 18 characteristics measured showed a difference between males and females from 70 days after hatching. Each of these characteristics were significantly different between sexes (ANCOVA, P<0.05), and the ratio of standard length between sexes showed that males were larger than females for all five morphometric measurements. Fin length measurements were taken for 21 distances of anal fin and 7 distances of dorsal fin between landmarks. There were all differences for all dorsal fin rays between the males and the females and there is significant difference in 70 days after their hatch when the sexual dimorphism is presented. The significant difference (P<0.05) in fin ray for male and female was more greatly seen as they grow. Male marine medaka showed more rapid growth than females, with longer length, dorsal fins and anal fins. Differences in these characteristics will be useful during experiments when it is necessary to differentiate between sexes of marine medaka.

• Food Science of Animal Resources
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• v.33 no.3
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• pp.390-394
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• 2013

The aim of this study was to determine the optimal storage condition of pre-packed Hanwoo beef without freezing. Hanwoo loin was purchased from a local distributor at 48 h after slaughter, then sliced in $1.5{\pm}0.5$ cm thickness, and packed in a polyethylene (PE) tray covered with linear low-density polyethylene (LLDPE) film. The studied factors to set the optimal storage condition were chamber temperature (5, 2.5 and $-1^{\circ}C$ for 14 d), cooling method (direct and indirect cooling system), and ultraviolet (UV) light irradiation for beef surface sterilization (0, 30, 60, and 120 min). The changes of pH, thiobarbituric acid reactive substances (TBARS) and number of aerobic bacteria were measured during storage. Beef samples stored in $-1^{\circ}C$ showed the minimal increasing rate in TBARS and microbial growth. After 15 d of storage, there was no significant difference in pH and TBARS values. However, the microbial population of beef stored in direct type cooling chamber ($4.25{\pm}0.66$ Log CFU/g) was significantly lower than that of beef stored in indirect type chamber ($6.47{\pm}0.08$ Log CFU/g) (p<0.05). After 4 d of storage, 60 or 120 min UV light irradiated beef samples showed significantly lower microbial population, and at 14 d of storage, 60 min UV irradiated beef sample showed significantly lower microbial population ($3.14{\pm}0.43$ Log CFU/g) than control ($4.46{\pm}0.13$ Log CFU/g) (p<0.05). However, TBARS values of 60 or 120 min UV light irradiated beef samples were significantly higher than non-irradiated beef sample after 4 d of storage (p<0.05).

• Journal of Biomedical Engineering Research
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• v.20 no.1
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• pp.37-44
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• 1999

Because of bone resorption, wear of ultra-high molecular weight polyethylene(UHMWPE) in total knee arthroplasty has been recognized as a major factor in long-term failure of knee implant. The surface damage and the following harmful wear debris of UHMWPE is largely related to contact stress. Most of the previous studies focused on the contact condition only at the articulating surface of UHMWPE. Recently, contact stress at the metal-backing interface has been implicated as one of major factors in UHMWPE wear. Therefore, the purpose of the is study is to investigate the effect of the contact stress for different thickness, conformity friction coefficient, and flexion degree of the UHMWPE component in total knee system, considering the contact conditions at both interfaces. In this study, a two-dimensional non-linear plane strain finite element model was developed. The results showed that the maximum value of von-Mises stress occurred below the articulating surface and the contact stress was lower for the more conforming models. All-polyethylene component showed lower stress distribution than the metal-backed component. With increased friction coefficient on the tibiofemoral contact surface, the maximum shear stress increased about twofold.

• Journal of Bio-Environment Control
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• v.19 no.3
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• pp.123-129
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• 2010

A study on modeling of medium temperature drops of the elevated-bench hydroponic system for strawberry cultivation during low temperature season was conducted. Four different conditions were used for the experiment. These consisted of two kinds of bed types (plant, V), four kinds of medium (rice, perlite, rice hulls80% and peatmoss20%, perlite80% and peatmoss20%), two kinds of mulched bed (mulched, non mulched) and four kinds of greenhouse air temperature (l.5, 3.2, 5.0, $6.7^{\circ}C$), and the results were summarized as follows: Temperature drop of medium in the V-bed was slower than that in the plant bed, showing better insulation effect of V-bed. Temperature drop of medium with mulching on the top of the bed was slower than the case without mulching, as a result, the beneficial effect of temperature drop was appeared in mulched bed. Linear regression of the temperature descent rate and the temperature difference between medium and air showed significant correlation. The regression equation for the Pearlite80% and Peatmoss20% in the V-bed was f(x) = -0.2656 + 0.1345x at the $R^2$ of 0.9269. Using the model, the temperature drop during night can be predicted for the various media at the different depths.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.5
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• pp.84-95
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• 2019

This paper reports the process of seismic fragility analysis for the rahman-type continuous bridge system. The target structure was the five span highway bridge with maximum pier hight of 72m. OpenSees software was used for the nonlinear time history analysis. In this study, 50 ground motions are considered for nonlinear time history analysis. For each ground motion, PGA was scaled from 0.1g to 2.0g with intervals of 0.1g in order to consider a wide range of the seismic intensity measure. In addition, yield displacement and ultimate displacement of each pier were calculated through section analysis. Based on the result of non linear time history analysis and section analysis, damage condition of target bridge was classified according to the definition of damage condition proposed by Barbat et al. As a result, it was predicted that Extensive Damage occurred at P1 when 0.731 g earthquake occurred in the longitudinal direction. Based on the seismic fragility analysis results, it is found that the probability of occurrence of Extensive Damage in the 4,800 - year period earthquake was about 4.2%. Therefore the target bridge has enough safety for earthquake.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.4
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• pp.704-713
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• 1997

This study was conducted to describe qualitatively the protein metabolism of pigs during growth depending on the feed protein quality and to describe quantitatively amino acids requirements, using a simulation model. The used model has a non-linear structure. In the used model, the protein utilization system of a pig, which is in the non-steady-state, is described with 15 flux equations and 11 differential equations and is composed with two compartments. Protein deposition(g/day) of pigs on the 30th, 60th, 90th, and 120th day of feeding duration with three-quality protein, beginning with body weight 20kg, were calculated according to the empirical model, PAF(the product of amino acid functions) of Menke, and was used as object function for the simulation. The mean of relative difference between the simulated protein deposition and PAF calculated values, lied in a range of 8.8%. The simulated protein deposition showed different behavior according to feed protein quality. In the high-quality protein, it showed paraboloidal form with extending growth simulation up to 150eh day. So the maximum of protein deposition was acquired on the 105th day of simulate growth time and then it decreased fast. In the low-quality protein, this form of protein deposition in the course of simulated growth did not appear until 150th day. The simulated protein mass also showed a difference in accordance with feed protein quality. The difference was small on the 30th day of simulated growth, but with duration of the simulated growth it was larger. On the 150th day the simulated protein deposition of high quality protein was 1.5 times higher as compared to the low-quality protein. The simulated protein synthesis and break-down rates(g/day) in the whole body showed a parallel behavior in the course of growth, according to feed protein quality. It was found that the improvement of feed protein quality increased protein deposition in the whole body through a increase of both protein synthesis and breakdown during growth. Also protein deposition efficiency, which was calculated from simulated protein deposition and protein synthesis, showed a difference in dependence on the protein qualify of feed protein. The protein deposition efficiency was higher in pigs fed with high quality protein, especially at the simulation time 30th day. But this phenomena disappeared with growth, so on the 150th day of growth, the protein deposition of the high feed protein quality was lowest among the three different quality of feed protein. The simulated total requirement of the 10 essential amino acids for the growth of pigs was 28.1(g/100g protein), similar to NRC. The requirement of lysine was 4.2(g/100g protein).