• Journal of Biomedical Engineering Research
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• v.20 no.4
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• pp.471-477
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• 1999

Many researches have been performed whether electrical stimulation could be used for diagnosis and treatment on the auditory system impairment. Unfortunately, there were no standard methods or theoretical background for choosing stimulus conditions because of the lack of understanding on the transmission of electrical stimulation through the auditory pathway. This research was conducted to observe the effect of electrical stimulation on the tinnitus-induced animals. Nine guniea pigs were used for the experment and divided into two groups, five animals for the experimental group(A) and four animals for the control group(B). Experimental conditions were divided into four steps, before tinnitus induction and 1, 6, 12 hours after tinnitus induction using salicylate based on the Jastreboff model. In each experimental condition, ABR and ECochG were obtained, and autocorrelation coefficients were calculated from normalized waveforms based on rms values. Sum of all the autocorrelation coefficients was extracted as a parameter to observe the changes between before and after the electrical stimulation. As a result, ABR parameter values were rapidly increased 6 hours after tinnitus induction, the gradually returned back to the initial state. On the other hand, when electrical stimulation was applied, parameter values did not change compared with the initial sate. Parameter values of ECochG showed that the effect of electrical stimulation appeared 12 hours after the tinnitus induction. It was concluded that an electrical stimulation to the tinnitus-induced model changes the correlation coefficients of ABR and ECochG waveforms.

• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.10-24
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• 2013

The state-of-arts of multiscale simulation (MSS) in science and engineering is briefly presented and MSS for process development (PD-MSS) is proposed to effectively apply the MSS to the process development. The four-level PD-MSS is composed of PLS (process-level simulation), FLS (fluid-level simulation), mFLS (microfluid-level simulation) and MLS (molecular-level simulation). Characteristics and methods of each level, as well as connectivity between the four levels are described. For example in PD-MSS, absorption column, fluidized-bed reactor, and adsorption process are introduced. For successful MSS, it is necessary to understand the multiscale nature in chemical engineering problems, to develop models representing physical phenomena at each scale and between scales, to develop softwares implementing mathematical models on computer, and to have strong computing facilities. MSS should be performed within acceptable accuracy of simulation results, available computation capacity, and reasonable efficiency of calculation. Macroscopic and microscopic scale simulations have been developed relatively well but mesoscale simulation shows a bottleneck in MSS. Therefore, advances on mesoscale models and simulation tools are required to accurately and reliably predict physical phenomena. PD-MSS will find its way into a sustainable technology being able to shorten the duration and to reduce the cost for process development.

• Journal of the Korea Concrete Institute
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• v.15 no.6
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• pp.848-855
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• 2003

During concrete placement, the partially distributed load due to the concrete placement paths creates the lateral force in the connection parts of the shore. In order to restrain this lateral force, the nails must be used in the upper and lower connection parts of shores. But, for the convenience of the construction and dismantling of the shores, the workers hardly use the nails. In this case, the connections of shore cannot resist the shear force and rotation. And this situation may cause the collapse of form-shore system. Therefore, contact and spring models for the connection analysis of the form-shore systems are required. If we take into account this construction situation, we need to understand the effects of shear and rotation stiffness according to the several types of connection parts in shores as a case study. This study evaluates the shear and rotation stiffness of the connection parts of shores according to the variations of the lengths, numbers and positions of nails, and then presents the experimental results depending on the end conditions of shores. And, these results can be used as a spring model and critical load evaluation data for the connection analysis of form-shore system.

• Journal of Radiation Protection and Research
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• v.32 no.1
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• pp.1-8
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• 2007

A model for radiological dose assessment in an urban environment, METRO-K has been developed. Characteristics of the model are as follows ; 1) mathematical structures are simple (i.e. simplified input parameters) and easy to understand due to get the results by analytical methods using experimental and empirical data, 2) complex urban environment can easily be made up using only 5 types of basic surfaces, 3) various remediation measures can be applied to different surfaces by evaluating the exposure doses contributing from each contamination surface. Exposure doses contributing from each contamination surface at a particular location of a receptor were evaluated using the data library of kerma values as a function of gamma energy and contamination surface. A kerma data library was prepared fur 7 representative types of Korean urban buildings by extending those data given for 4 representative types of European urban buildings. Initial input data are daily radionuclide concentration in air and precipitation, and fraction of chemical type. Final outputs are absorbed dose rate in air contributing from the basic surfaces as a function of time following a radionuclide deposition, and exposure dose rate contributing from various surfaces constituting the urban environment at a particular location of a receptor. As the result of a contaminative scenario for an apartment built-up area, exposure dose rates show a distinct difference for surrounding environment as well as locations of a receptor.

• Journal of the Korean School Mathematics Society
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• v.14 no.4
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• pp.423-442
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• 2011

The purpose of this study was to examine the effects of tasks setting for mathematical modelling in the complex real situations. The tasks setting(MMa, MeA) in mathematical modelling was so important that we can't ignore its effects to develop meaning and integrate mathematical ideas. The experimental setting were two groups ($N_1=103$, $N_2=103$) at public high school and non-experimental setting was one group($N_3=103$). In mathematical achievement, we found meaningful improvement for MeA group on modelling tasks, but no meaningful effect on information processing tasks. The statistical method used was ACONOVA analysis. Beside their achievement, we were much concerned about their modelling approach that TSG21 had suggested in Category "Educational & cognitive Midelling". Subjects who involved in experimental works showed very interesting approach as Exploration, analysis in some situation ${\Rightarrow}$ Math. questions ${\Rightarrow}$ Setting models ${\Rightarrow}$ Problem solution ${\Rightarrow}$ Extension, generalization, but MeA group spent a lot of time on step: Exploration, analysis and MMa group on step, Setting models. Both groups integrated actively many heuristics that schoenfeld defined. Specially, Drawing and Modified Simple Strategy were the most powerful on approach step 1,2,3. It was very encouraging that those experimental setting was improved positively more than the non-experimental setting on mathematical belief and interest. In our school system, teaching math. modelling could be a answer about what kind of educational action or environment we should provide for them. That is, mathematical learning.

• Korean Journal of Remote Sensing
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• v.36 no.2_2
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• pp.325-335
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• 2020

Forest canopy height can be used for estimate of above-ground forest biomass (AGB) by means of the allometric equation. The remote locations and harsh conditions of mangrove forests limit the number of field inventory data stations needed for large-scale modeling of carbon and biomass dynamics. Although active and passive spaceborne sensors have proven successful in mapping mangroves globally, the sensors generally have coarse spatial resolution and overlook small-scale features. Here we generate a 12 m spatial resolution mangrove canopy height map from TanDEM-X data acquired over the world largest intact mangrove forest located in the Sundarbans. With single-pol. TanDEM-X data from 2011 to 2013, the proposed technique makes use of the fact that the double-bounce scattering that occurs between the water and mangrove trees yields water surface level elevation over mangrove forest areas, thus allowing us to estimate forest height with the assumption of an underlying flat topography. Our observations have led to a large-scale mangrove canopy height map over the entire Sundarbans region at a 12 m spatial resolution. Our canopy height estimates were validated with ground measurements acquired in 2015, a correlation coefficient of 0.83 and a RMSE of 0.84 m. With globally available TanDEM-X data, the technique described here will potentially provide accurate global maps of mangrove canopy height at 12 m spatial resolution and provide crucial information for understanding biomass and carbon dynamics in the mangrove ecosystems.

• Applied Biological Chemistry
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• v.47 no.3
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• pp.351-356
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• 2004

Holographic quantitative structure activity relationships (HQSAR) as 2D QSAR between the herbicidal activities against root and shoot of rice plant (Orysa sativa L.) and barnyardgrass (Echinochloa crus-galli), and structures of A=3,4,5,6-tetra-hydrophthalimino, B = 3-chloro-4,5,6,7-tetrahydro-2H-indazolyl and C = 3,4-dimethylmaleimino substituents in 1-(5-methyl-3-phenylisoxazolin-5-yl)methoxy-2-chloro-4-fluorobenzene derivatives were studied and discussed. The statistical results of four HQSAR models for the herbicidal activities against root and shoot of the two plants showed the best predictability of the herbicidal activities based on the cross-validated $r^2\;_{cv}\;(q^2=\;0.760{\sim}0.924)$, non cross-validated conventional coefficient $(r^2\;_{ncv}\;=\;0.868{\sim}0.970)$ and PRESS values $(0.123{\sim}0.261)$. The results indicated that the qualities of HQSAR models for barnyardgrass were slightly higher than that of rice plant. And also, the predictability of HQSAR models were higher $(q^2\;=\;HQSAR\;>\;CoMFA)$ than CoMFA but the conventional coefficients of HQSAR models lower $(r^2\;=\;HQSAR\;<\;CoMFA)$ than CoMFA. Moreover, from the contribution maps, it was founded that the selectivity between the two plants depends upon the 2-fluoro-4-chloro-5-alkoxyanilino and $R_3$ substituent on the C-phenyl ring. These features suggest where to modify a molecular structure in order to improve its selective of herbicidal activities against barnyardgrass.

• Economic and Environmental Geology
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• v.51 no.3
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• pp.223-232
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• 2018

The viscous force of fluids and the capillary force acting on the pore network of the porous media are important factors determining the immiscible displacement during geological $CO_2$ sequestration, these were directly affected by geological formation conditions and injection conditions. This study aimed to observe the migration and distribution of injected fluid and pore water, and quantitatively investigate displacement efficiency on various injection temperatures. This study aimed to perform micromodel experiments by applying n-hexane used as a proxy fluid for supercritical $CO_2$. In this study, immiscible displacement process from beginning of n-hexane injection to equilibrium of the distribution of the n-hexane and pore water was observed. The images from experiment were used to observe the displacement pattern and estimate the areal displacment efficiency of the n-hexane. For investigate the affects of the injection temperatures on the migration in macroscopic, migration of n-hexane in single pore was analyzed. The measurement revealed that the displacement efficiency at equilibrium state decreases as the temperature increases. The result from experiments indicate that the temperatures can affect the displacement pattern by changing the viscous forces and the capillary forces. The experimental results could provide important fundamental information on reservoir conditions and fluid injection conditions during geological $CO_2$ sequestration.

• Korean Journal of Construction Engineering and Management
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• v.11 no.4
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• pp.22-31
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• 2010

Because the estimated cost at early stage has great influence on decisions of project owner, the importance of early cost estimation is increasing. However, it depends on experience and knowledge of the estimator mainly due to shortage of information. Those tendency developed into case-based reasoning(CBR) method which solves new problems by adapting previous solution to similar past problems. The performance of CBR model is affected by attribute weight, so that its accurate determination is necessary. Previous research utilizes mathematical method or subjective judgement of estimator. In order to improve the problem of previous research, this suggests CBR schematic cost estimation method using genetic algorithm to determine attribute weight. The cost model employs nearest neighbor retrieval for selecting past case. And it estimates the cost of new cases based on cost information of extracted cases. As the result of validation for 17 testing cases, 3.57% of error rate is calculated. This rate is superior to accuracy rate proposed by AACE and the method to determine attribute weight using multiple regression analysis and feature counting. The CBR cost estimation method improve the accuracy by introducing genetic algorithm for attribute weight. Moreover, this makes user understand the problem-solving process easier than other artificial intelligence method, and find solution within short time through case retrieval algorithm.

• The Journal of Korean Academy of Sensory Integration
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• v.12 no.1
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• pp.39-50
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• 2014

Objective : The purpose of this study was to provide for the intervention and outcome measurement tools of children with Attention Deficit Hyperactivity Disorder (ADHD) through ICF model. Methods : The systematic review methods were used. Papers published in the journal between January, 2000 and July, 2014 were searched through MEDLINE/PubMed, Sciencedirect, Ovid. The main terms searched were 'ADHD, Children, intervention, outcome measure', and 8 papers were analyzed. Results : 1. The subjects of ADHD were pure ADHD (75.8%), ADHD with dyslexia (9.1%), ADHD with conduct disorder (5.8%), ADHD with tic disorder (3.8%), ADHD with DCD (3.0%), ADHD with emotional disorder (2.5%). 2. The nonpharmacologic intervention of ADHD were functioning and disability (80%) and contextual factors (20%). Most frequently used intervention were body function and structure (60%). 3. The outcome measurement tools of ADHD were functioning and disability (80.5%) and contextual factors (19.5%). Most frequently used outcome measurement tools were body function and structure (70.8%). Conclusion : This study can provide information on the intervention and outcome measurement tools of ADHD.