• Computers and Concrete
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• v.20 no.1
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• pp.23-29
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• 2017

In this study engineered steel fibres used as reinforcement for concrete were characterized by number of key mechanical and spatial parameters, which are easy to measure and quantify. Such commonly used parameters as length, diameter, fibre intrinsic efficiency ratio (FIER), hook geometry, tensile strength and ductility were considered. Effective classification of various fibres was demonstrated using simple multivariate computations involving principal component analysis (PCA). Contrary to univariate data mining approach, the proposed analysis can be efficiently adapted for fast, robust and direct classification of engineered steel fibres. The results have revealed that in case of particular spatial/geometrical conditions of steel fibres investigated the FIER parameter can be efficiently replaced by a simple aspect ratio. There is also a need of finding new parameters describing properties of steel fibre more precisely.

• Journal of Korean Physical Therapy Science
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• v.5 no.4
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• pp.809-816
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• 1998

This study was conducted to evaluated the effects adding continuous passive motion(CPM) each day to the entire postoperative program of patients who received a total knee replacement(TKR). A retrospective chart review was completed for 31 patients(12 with bilateral involvement, totaling 44 knees)who received a TKR between 1996 and 1998. The data analysis compared the following variables for 28 patients who received CPM and 16 patients who received no CPM: the length of hospital stay(LOS), the frequency of postoperative complications, the number of post-operative days(PODs) range of motion (ROM). The CPM Group showed significant decreases in the frequency of complication(p<0.05), the LOS(p < 0.05), and No difference was demonstrated in the ROM of the two groups. We concluded that CPM was an effective adjunct to physical therapy care of patients undergoing total knee replacement.

• Journal of Power System Engineering
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• v.5 no.1
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• pp.50-56
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• 2001

Jet pumps are used in a great number of engineering applications. In the present study, jet shapes, mixing chamber shapes, and numerical methods for predicting the performance of an annular-type jet pump are investigated to determine the optimal turbulence model. The flow fields are simulated by solving the momentum and the continuity equations with the standard ${\kappa}-{\epsilon}$ and the RNG ${\kappa}-{\epsilon}$ turbulence models at different Reynolds numbers. After that, they are compared with the corresponding experimental data to determine the optimal model. Next, various calculations are conducted to find an optimal shape using the selected turbulence model. The study shows us that the RNG ${\kappa}-{\epsilon}$ model predicts the performance more exactly, and also shows that the most effective performance can be achieved with $12^{\circ}$ reducing angle and 130mm throat length.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1468-1473
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• 2011

With the proliferation of wireless LAN and smart phones, IP local broadcasting technology has been developed, and the new solution should be studied for error corrupted frames in the wireless broadcasting channel. In push service system using point-to-multi-point connection among broadcasting server and receivers, the technology proposed in this paper provides an effective data broadcasting system by employing frame length adjustment, redundant transmission, and repetitive transmission method.

• Magazine of the Korean Society of Agricultural Engineers
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• v.22 no.2
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• pp.64-82
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• 1980

The aim of this thesis, when water permeates dam, is to study the shape of seepage line and seepage quantity. As for the process, various sand model dams of same capacity were constructed in the water tank : they are a central, middle, inclined, up and down stream point of which is paralled, and filter-installed types. And the slope of seepage line and seepage quantity in these various models for experiment were measured, observed data were analyzed, and several formulas which already published were compared and examined. As for the shape of seepage line, the relation between upstream water level and exit: slope of seepage line, near the entrance and exit point, geometrically similar model, and the shape of seepage line filter-installed were examined. As regards to the seepage quantity, several formulas which already published and testing result values were compared and examined, and relation with the slope of seepage line, the seepage quantity, the slope of upstream point, and the upstream water level were mutually studied. Particulary, when horizontal filter was installed, propriety of the existing formulas for effective filter length w as examined, and the relative position of exit point in various. conditions was also studied.

• Smart Structures and Systems
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• v.6 no.9
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• pp.991-1005
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• 2010

The key to detecting damage to civil engineering structures is to find an effective damage indicator. The damage indicator should promptly reveal the location of the damage and accurately identify the state of the structure. We propose to use the distance measures of low-order AR models as a novel damage indicator. The AR model has been applied to parameterize dynamical responses, typically the acceleration response. The premise of this approach is that the distance between the models, fitting the dynamical responses from damaged and undamaged structures, may be correlated with the information about the damage, including its location and severity. Distance measures have been widely used in speech recognition. However, they have rarely been applied to civil engineering structures. This research attempts to improve on the distance measures that have been studied so far. The effect of varying the data length, number of parameters, and other factors was carefully studied.

• Journal of the Korea Society for Simulation
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• v.8 no.2
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• pp.29-43
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• 1999

As real-time processing of data with large storage space is required in the era of multimedia, disk arrays are generally used as storage subsystems which be able to provide improved I/O performance. To design the cost-effective disk array, it is important to develop performance models which evaluate the disk array performance. Both queueing theory and simulation are applicable as the method of performance evaluation through queueing modeling. But there is a limit to the analytical method using queueing theory due to the characteristics of disk array requests being serviced in the parallel and concurrent manner. So in this paper we evaluate the disk array performance using simulation method which abstract disk array systems in the low level. Performance results were evaluated through simulation, so that mean response time, mean queueing delay, mean service time, mean queue length for disk array requests and utilization, throughput for disk array systems, can be utilized for capacity planning in the phase of disk array design.

• Korean Journal of Child Studies
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• v.24 no.4
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• pp.89-102
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• 2003

A model for teaching traditional Korean rhythmic patterns using Orff's ear training approach was developed and implemented with aim that it could be used as basic data for the operation of Korean music education. Children's rhythmic sense improved through teaching of sound searching, body rhythm, playing instruments, and improvising. Teaching the order of connective rhythmic patterns and a basic patterns-centered approach was more effective than teaching modified rhythmic patterns. With ear training, children perceived the stress of rhythmic patterns in advance and they perceived the length of sound. These results show that this model can be used as a basic approach in the operation of Korean music education.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2305-2307
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• 2000

In this paper we propose a Neuro-Fuzzy modeling method using mGA for complex nonlinear system. mGA has more effective and adaptive structure than sGA with respect to using the changeable-length string. This paper suggest a new coding method for applying the model's input and output data to the number of optimul rules of fuzzy models and the structure and parameter identifications of membership function simultaneously. The proposed method realize optimal fuzzy inference system using the learning ability of Neural network. For fine-tune of the identified parameter by mGA, back-propagation algorithm used for optimulize the parameter of fuzzy set. The proposed fuzzy modeling method is applied to a nonlinear system to prove the superiority of the proposed approach through compare with ANFIS.

• Journal of Korean Biological Nursing Science
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• v.21 no.4
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• pp.292-299
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• 2019

Purpose: The purpose of this study was to determine whether poor preoperative nutritional status in elderly patients exhibited a negative influence on postoperative clinical outcomes. Methods: The medical records of 645 elderly patients were examined retrospectively. The patients had undergone major surgery between January 2017 and January 2018. Their nutritional status was measured using the Nutritional Risk Screening 2002. The data were analyzed using the chi-squared test, the Mann-Whitney U test, logistic regression, linear regression, Cox proportional hazards regression, and the Kaplan-Meier analysis. Results: Preoperative malnutrition was found in 73 patients (11.3%). Poor preoperative nutritional status was significantly associated with pressure ulcers, length of hospitalization, discharge to patient care facilities rather than home, and mortality rate at three months. Conclusion: Preoperative malnutrition in elderly patients was associated with negative postoperative clinical outcomes. These results indicate that an effective nutritional program before surgery can lead to a more rapid postoperative recovery.