• Journal of the Korean School Mathematics Society
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• v.18 no.3
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• pp.281-309
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• 2015

The purpose of this study is provides an implication of further teaching learning process by analyze the common and difference and characteristic of mathematical self-efficiency between three peer tutoring groups discourse in the mathematical teaching leaning process that use peer tutoring. To achieve this goal, three groups formed that consist of one peer tutor who received a first grade of mathematic achievement and one peer student. Peer student of each group is divided into high grade, middle grade, low grade of mathematic achievement. Then analyze the discourse in the exponential function problem solving process. Based on the results of study, this paper provides a concrete example of merit of peer tutoring on the peer tutor. Result of study also provides a practical help to make a peer tutoring group by considering a difference of grades between peer tutor and peer student. Because there is a possibility of mutual discourse on the tutoring group that consist of similar grades.

• Journal of the Korean Magnetics Society
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• v.11 no.3
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• pp.134-140
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• 2001

Flux-gate magnetometer was developed in 1930's, and it has been widely used for the low magnetic field measurements. In this work, we have employed amorphous ribbon 2714A produced by Allied Chem. Co. as sensor core material. To develop low noise, low power consumption, and high reliability flux-gate magnetometer, we have measured ac magnetic properties depending on the annealing conditions. As quenched state amorphous core shows high noise level and ac magnetic properties were changed under the condition of accelerated aging test, but amorphous ribbon, which was annealed under 350 $\^{C}$ during 1 hour, shows low noise level of 0.1 nT in the frequency range of dc∼10 Hz which was 10 times better than the as quenched amorphous ribbon. Under accelerated aging test, ac magnetic properties such as squareness and coercivity of the annealed samples show higher reliability and approached to a certain limiting value as exponential function. We can see that high reliability and low noise flux-gate magnetometer could be developed, if we consider this ac magnetic properties change in the sensor design.

• Journal of the Korea Society of Computer and Information
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• v.20 no.1
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• pp.197-206
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• 2015

Defect severity that is a measure of the impact caused by the defect plays an important role in software quality activities because not all software defects are equal. Earlier studies have concentrated on defining defect severity levels, but there have almost never been trials of measuring module severity. In this paper, first, we define a defect severity metric in the form of an exponential function using the characteristics that defect severity values increase much faster than severity levels. Then we define a new metrics set for software module severity using the number of defects in a module and their defect severity metric values. In order to show the applicability of the proposed metrics, we performed an analytical validation using Weyuker's properties and experimental validation using NASA open data sets. The results show that ms is very useful for measuring the module severity and msd can be used to compare different systems in terms of module severity.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.5
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• pp.377-383
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• 2016

The effect of long-term aging degradation on magnetic properties of ferritic 11Cr low-carbon steel was investigated. Coercivity and hysteresis loss measured from the hysteresis loops decreased with long-term aging time and showed that the relation was well fitted by a second order exponential function. Vickers hardness also decreased with aging time and resulted in mechanical softening. In addition, the microstructural evolution was observed by the scanning electron microscopy, backscattered electron image and X-ray diffraction. The $Cr_{23}C_6$ precipitates along grain boundary grew fast and Laves ($Fe_2W$) phase on martensitic lath boundaries in interior grains was developed. The solid solution atoms depleted in matrix and lath subgrains recovered owing to precipitate coarsening with long-term aging degradation. There was a close relation with softening of magnetic and mechanical properties.

• Journal of IKEEE
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• v.20 no.4
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• pp.398-411
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• 2016

SVM, a machine learning method, is widely used in image processing for it's excellent generalization performance. However, to add other data to the pre-trained data of the system, we need to train the entire system again. This procedure takes a lot of time, especially in embedded environment, and results in low performance of SVM. In this paper, we implemented an SVM trainer and classifier in an FPGA to solve this problem. We parlallelized the repeated operations inside SVM and modified the exponential operations of the kernel function to perform fixed point modelling. We implemented the proposed hardware on Xilinx ZC 706 evaluation board and used TSR algorithm to verify the FPGA result. It takes about 5 seconds for the proposed hardware to train 2,000 data samples and 16.54ms for classification for $1360{\times}800$ resolution in 100MHz frequency, respectively.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.1
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• pp.37-44
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• 2009

Density is the most important congestion indicator among the three fundamental flow variables, flow, speed and density. Measuring density in the field has two different ways, direct and indirect. Taking photos with wide views is one of direct ways, which is not widely used because of its cost and lacking of proper positions. Another direct density measuring method using two spot detectors has been introduced with the concept of instantaneous density, average density and measurement interval. The relationship between accuracy and measurement interval has been investigated using the simulation data produced by Paramics API function. Finally, density measurement algorithm has been suggested including exponential smoothing for device development.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.10
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• pp.895-900
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• 2016

Remaining useful life (RUL) estimation of the Li-ion battery has gained great interest because it is necessary for quality assurance, operation planning, and determination of the exchange period. This paper presents the RUL estimation of an Li-ion battery for an energy storage system using exponential function for the degradation model and Markov Chain Monte Carlo (MCMC) approach for parameter estimation. The MCMC approach is dependent upon information such as model initial parameters and input setting parameters which highly affect the estimation result. To overcome this difficulty, this paper offers a guideline for model initial parameters based on the regression result, and MCMC input parameters derived by comparisons with a thorough search of theoretical results.

• International Journal of Highway Engineering
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• v.8 no.3 s.29
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• pp.29-37
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• 2006

The primary objective of this study is to characterize traffic axle loadings that consider Korea specific traffic conditions for developing mechanistic-based pavement design method as a part of Korea Pavement Research Program(KPRP). Although the concept of equivalent single axle load(ESAL) has been generally used since the 1960s for the pavement design, the mechanistic-based pavement design procedure requires more accurate axle loading data on the specific pavement. In this study, axle loading data were collected according to vehicle type and highway functional classification. Axle-load spectrum was then standardized by cumulative density function(cdf), because the axle load spectrum could vary from the observed site, truck traffic volume, and truck type, Finally, this study presented the procedure and S-shaped exponential models for characterizing axle load spectra according to vehicle type and highway functional classification.

• The Korean Journal of Applied Statistics
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• v.8 no.1
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• pp.89-104
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• 1995

This paper is concerned with the method of estimating lifetime distributin from field data for products with multiple modes of failure. When product failures occur within warranty period, a manufacturer can obtain failure-record data; failure times, causes of failure, and covariates. Since these data are seriously incomplete for satisfactory inference, that is, only failures occured during warrantly period may be recorded, it is usually necessary to incoporate the failure-record data by taking a supplementary sample of items obtained following up a portion of products that survive warranty time. The log linear function is considered as a model for describing the relation between failure time of a product and covariates. General methods for obtaining pseudo maximum likelihood estimators(PMLEs) for the parameters are outlined and their asymptotic properties are studied, and specific formulas for exponential or Weibull distribution are obtained. Effects of follow-up percentage on the PMLEs are investigated. Extensions to calendar time warranty or calendar and obtaining time warranty are also considered.

• Journal of KIISE:Software and Applications
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• v.32 no.11
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• pp.1059-1070
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• 2005

For genetic algorithms, the population may get stuck in a local optimum. The population can escape from this after a long duration. This phenomenon is called punctuated equilibrium. The punctuated equilibria observed in nature and computational ecosystems are known to be well described by diffusion equations. In this paper, simple genetic algorithms are theoretically analyzed to show that they can also be described by a diffusion equation. When fitness is the function of unitation, this analysis can be further refined to make the parameters of genetic algorithms appear in this equation. Using theoretical results on the diffusion equation, the duration of equilibrium is shown to be exponential of such parameters as population size, 1/(mutation probability), and potential barrier. This is corroborated by simulation results for bistable potential landscapes with one local optimum and one global optimum.