• Journal of the Korean Geophysical Society
• /
• v.3 no.4
• /
• pp.251-260
• /
• 2000

Applicabilities of two numerical methods, the 2-dimensional and the 3-dimensional method, are evaluated to inverse test results obtained from the underwater SASW(Spectral -Analysis-of-Surface-Waves) method. As a result of this study, it has been found that the 2-dimensional method can supposed to be applicable for the cases where stiffness of soil layer increases gradually with depth, and the stiffness is relatively low. For the other cases, however, it has been concluded that the 3-dimensional method needs to be applied to determine realistic theoretical dispersion curves. An example is also shown that in situ soil profile underwater is estimated from experimental dispersion curves using the 3-dimensional method. As a results, it can be concluded that the underwater SASW method can be effectively applied to explore the underwater soil condition.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.9 no.5
• /
• pp.555-565
• /
• 1999

The optimal identification algorithm of fuzzy systems is presented for rule-based fuzzy modeling of nonlinear complex systems. Nonlinear systems are expressed using the identification of structure such as input variables and fuzzy input subspaces, and parameters of a fuzzy model. In this paper, the rule-based fuzzy modeling implements system structure and parameter identification using the fuzzy inference methods and hybrid structure combined with two types of optimization theories for nonlinear systems. Two types of inference methods of a fuzzy model are the simplified inference and linear inference. The proposed hybrid optimal identification algorithm is carried out using both a genetic algorithm and the improved complex method. Here, a genetic algorithm is utilized for determining initial parameters of membership function of premise fuzzy rules, and the improved complex method which is a powerful auto-tuning algorithm is carried out to obtain fine parameters of membership function. Accordingly, in order to optimize fuzzy model, we use the optimal algorithm with a hybrid type for the identification of premise parameters and standard least square method for the identification of consequence parameters of a fuzzy model. Also, an aggregate performance index with weighting factor is proposed to achieve a balance between performance results of fuzzy model produced for the training and testing data. Two numerical examples are used to evaluate the performance of the proposed model.

• Korean Journal of Community Nutrition
• /
• v.5 no.2
• /
• pp.172-184
• /
• 2000

To establish a basic cohort which can survey the nutrient and food intake related to the health status of the middle and old-aged vertically, a longitudinal survey of 110 adults over forty years old was conducted three times in Chon-ju city over 5 years (1994-1999), and the influences of health status by changes in their nutrient and food intake were examined in this study. The results were as follows ; The number of subjects was 110(43 man, 67 women), 10.0% in their forties, 28.2% in their fifties, 45.4% in their sixties 6.4% over seventy, and their average age was 61.4. There were decrease of height about 1cm , increase of body fat % and few changes of BMI during the testing period. As the subjects were aging, the percentage of anemia increased, but averages of blood pressure and blood glucose(men : 91.8mg/㎗, women : 90.3mg/㎗) were constant. Total cholesterol increased from 196.7mg/㎗ to 212.6mg/㎗(P 0.05) over five years, and the numerical values for women were higher than that of men. In many cases, lack of nutrient intake was shown, as compared with the Recommended Dietary allowance(RDA) especially calcium and vitamin A(71.7%, 64.9% of RDA). Grains intake showed a tendency to decrease(P 0.01). On the contrary, fruit intake showed a tendency to increase(P 0.001). On whole meal, plant foods were 85.1% and animal foods were 14.9%. As dietary factors influencing health status were investigated, blood glucose was influenced by vitamin B$_2$, potatoes and triglyceride, DBP and SBP were affected by vitamin B$_1$, vitamin C, legumes, fishes, triglyceride and age. Total cholesterol was under the influence of triglyceride, milk, seeds and fat. BMI was influenced by iron, SBP, animal food, and age.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.5 no.4 s.19
• /
• pp.37-47
• /
• 2005

The purpose of this study is to estimate the bearing capacity and settlement characteristics of the weathered granite masses, and on the process to achieve the purpose, in the first place, the weathered degree according to the absorption index was examined and reviewed, then plate bearings test in in-situ depth were tested, and finally the result was compared and examined with the result of the existing, estimate method and pressuremeter test. In order to achieve the purpose of this study, a typical area distributed with weathered granite masses, gyeonggi area, was chosen as a sample site for testing, and in the result, it appeared and found out that the more the weathered degree increases when the plate bearing test are tested, the more the bearing capacity decreases a numerical indexes and the more greatly the width of the decrease of bearing capacity increases around the boundary of specific, weathered degrees. Also, In the result from estimating the bearing capacity of weathered granite masses by the existing, suggested formula, it appeared that there is a tendency that the more the weathered degree increases, the more similar the bearing capacity becomes with the result of plate bearing tests.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.8
• /
• pp.1903-1910
• /
• 2009

In this paper, we were researched decision problem called an optimal release policies after testing a software system in development phase and transferring it to the user. The applied model of release time exploited infinite failure non-homogeneous Poisson process This infinite failure non-homogeneous Poisson process is a model which reflects the possibility of introducing new faults when correcting or modifying the software. The failure life-cycle distribution used the Weibull distribution which has the efficient various property which has the place efficient quality. Thus, optimal software release policies which minimize a total average software cost of development and maintenance under the constraint of satisfying a software reliability requirement becomes an optimal release policies. In a numerical example, after trend test applied and estimated the parameters using maximum likelihood estimation of inter-failure time data, estimated software optimal release time.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.12
• /
• pp.2311-2318
• /
• 2007

Finite failure NHPP models presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. Accurate predictions of software release times, and estimation of the reliability and availability of a software product require Release times of a critical element of the software testing process : test coverage. This model called Enhanced non-homogeneous Poission process(ENHPP). In this paper, exponential coverage and S-shaped model was reviewed, proposes the Kappa coverage model, which make out efficiency application for software reliability. Algorithm to estimate the parameters used to maximum likelihood estimator and bisection method, model selection based on SSE statistics and Kolmogorov distance, for the sake of efficient model, was employed. Numerical examples using real data set for the sake of proposing Kappa coverage model was employed. This analysis of failure data compared with the Kappaa coverage model and the existing model(using arithmetic and Laplace trend tests, bias tests) is presented.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.8
• /
• pp.1574-1581
• /
• 2007

DVB-H (Digital Video Broadcasting for Handhold) is a new standard, currently being developed for a portable digital broadcasting, which enhance the multimedia broadcasting service in the Euroapean standard DVB-T (DVB-Terrestrial). Seamless mobility and power saving are essential requirements in the DVB-H system. To support seamless mobility, DVB-H system should provides seamless handover for mobile stations in the MFN (multi frequency network). For seamless handover, the receiver should monitor neighboring cells and it increases the power consumption. And so, power efficient sell searching algorithm for seamless handover is required. In this paper, we propose hypothesis feeling based handover algorithm to enhance the power efficiency by using the fast cell searching, and analyze the performance of handover schemes through the numerical evaluation and simulation.

• Annals of Rehabilitation Medicine
• /
• v.41 no.6
• /
• pp.924-934
• /
• 2017

Objective To investigate the anatomical correlates of the neuropsychological deficits in patients with the cerebellar stroke. Methods We screened patients who were admitted to the National Rehabilitation Center with the cerebellar stroke between October 2012 and November 2016. The patients with the cerebellar stroke who underwent neuropsychological testing for which the Seoul Neuropsychological Screening Battery (SNSB) or the SNSB-II were enrolled. The neuropsychological function capacities were compared in accordance with the stroke type (hemorrhagic vs. ischemic) and the location (right/left anterior, right/left posterior intermediate, right/left posterior lateral lobe, and vermis). Mean z-scores were computed to compare the patient performances with the population averages. Results Twenty-six patients (15 with ischemic stroke and 11 with hemorrhagic stroke) with a mean age of $54.8{\pm}16.6$ years were assessed $8.8{\pm}9.2$ months after the stroke. Differences in the neuropsychological functioning according to the stroke type were not observed. All of the numerical subtests of the stroke patients showed significantly poorer performances compared with the population averages (mean z-score <0), and some of the subtests revealed abnormal performances in attention-, visuospatial function-, memory-, and frontal/executive function-related tasks (mean z-score <-1). The patients with the presence of a lesion in the right posterior intermediate lobe of the cerebellum showed a poorer performance in the subtests evaluating the executive function including the Korean-version Stroop Test (p=0.04), the Digit Symbol Coding Test (p=0.01), and the Korean-version Trail Making Test (p=0.02) compared with the patients without that lesion. Conclusion The present study confirms that the cerebellar stroke affects the neuropsychological functioning which is associated with the anatomical site of stroke.

• Steel and Composite Structures
• /
• v.33 no.1
• /
• pp.19-36
• /
• 2019

Cyclic behaviour of composite (steel-concrete) plate shear walls (CPSW) with variable column flexural stiffness is experimentally and numerically investigated. The investigation included design, fabrication and testing of three pairs of one-bay one-storey CPSW specimens. The reference specimen pair was designed in way that its column flexural stiffness corresponds to the value required by the design codes, while within the other two specimen pairs column flexural stiffness was reduced by 18% and 36%, respectively. Specimens were subjected to quasi-static cyclic tests. Obtained results indicate that column flexural stiffness reduction in CPSW does not have negative impact on the overall behaviour allowing for satisfactory performance for up to 4% storey drift ratio while also enabling inelastic buckling of the infill steel plate. Additionally, in comparison to similar steel plate shear wall (SPSW) specimens, column "pull-in" deformations are less pronounced within CPSW specimens. Therefore, the results indicate that prescribed minimal column flexural stiffness value used for CPSW might be conservative, and can additionally be reduced when compared to the prescribed value for SPSWs. Furthermore, finite element (FE) pushover simulations were conducted using shell and solid elements. Such FE models can adequately simulate cyclic behaviour of CPSW and as such could be further used for numerical parametric analyses. It is necessary to mention that the implemented pushover FE models were not able to adequately reproduce column "pull-in" deformation and that further development of FE simulations is required where cyclic loading of the shear walls needs to be simulated.

• Computers and Concrete
• /
• v.10 no.1
• /
• pp.1-18
• /
• 2012

This paper presents the details of studies conducted on hollow concrete block masonry (HCBM) units and wall panels. This study includes, compressive strength of unit block, ungrouted and grouted HCB prisms, flexural strength evaluation, testing of HCBM panels with and without opening. Non-linear finite element (FE) analysis of HCBM panels with and without opening has been carried out by simulating the actual test conditions. Constant vertical load is applied on the top of the wall panel and then lateral load is applied in incremental manner. The in-plane deformation is recorded under each incremental lateral load. Displacement ductility factors and response reduction factors have been evaluated based on experimental results. From the study, it is observed that fully grouted and partially reinforced HCBM panel without opening performed well compared to other types of wall panels in lateral load resistance and displacement ductility. In all the wall panels, shear cracks originated at loading point and moved towards the compression toe of the wall. The force reduction factor of a wall panel with opening is much less when compared with fully reinforced wall panel with no opening. The displacement values obtained by non-linear FE analysis are found to be in good agreement with the corresponding experimental values. The influence of mortar joint has been included in the stress-strain behaviour as a monolith with HCBM and not considered separately. The derived response reduction factors will be useful for the design of reinforced HCBM wall panels subjected to lateral forces generated due to earthquakes.