• Proceedings of the KSR Conference
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• 2008.06a
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• pp.512-518
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• 2008

The importance of modern electronic devices is gradually increased and, the requirement of the safe and reliable earthing and bonding for protection of the electronic devices is consequently absolute. The electrical continuity and physical strength of the bonding work in rail signal and impedance bonding is also one of the important issues. The thermit welding for earth cable connection and rail bonding work proposed hereunder is an effectively applicable in many fields of rail industries.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.14 no.24
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• pp.71-81
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• 1991

인체의 운동은 많은 수의 자유도를 지닌 조인트(JOINT)와 링(LINK)의 복잡한 운동으로 표현될 수 있다. 이들 링크(LINK)의 회전 운동은 SINE, COSINE 자승 형태의 비선형 운동으로 이루어져있으나, 최근 PERSONAL COMPUTER의 발달로 복잡한 인체 운동의 수학적 모델에 대한 동력학적 DATA 계산이 가능해졌다. 본 연구에서는 5개의 링크(LINK)로 연결된 인체 움직임에 있어 링크(LINK)의 절대 운동(ABSOLUTE MOTION) 및 상대운동(RELATIVE MOTION)을 고려한 PLAGENHOEF의 운동 모델을 PERSONAL COMPUTER를 이용하여 인체 움직임의 동력학적 DATA를 얻을 수 있도록 BASIC 언어로 프로그램을 제기하였다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.14 no.23
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• pp.7-18
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• 1991

인체의 운동은 많은 수의 자유도를 지닌 조인트(JOINT)와 링(LINK)의 복잡한 운동으로 표현될 수 있다. 이들 링크(LINK)의 회전 운동은 SINE, COSINE 자승 형태의 비선형 운동으로 이루어져있으나, 최근 PERSONAL COMPUTER의 발달로 복잡한 인체 운동의 수학적 모델에 대한 동력학적 DATA 계산이 가능해졌다. 본 연구에서는 5개의 링크(LINK)로 연결된 인체 움직임에 있어 링크(LINK)의 절대 운동(ABSOLUTE MOTION) 및 상대운동(RELATIVE MOTION)을 고려한 PLAGENHOEF의 운동 모델을 PERSONAL COMPUTER를 이용하여 인체 움직임의 동력학적 DATA를 얻을 수 있도록 BASIC 언어로 프로그램을 제기하였다.

• Physical Therapy Korea
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• v.24 no.3
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• pp.21-29
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• 2017

Background: The measurement of the strength of the shoulder muscles is an important element of the overall assessment of patients with various shoulder disorders. However, the clinical utilization of this measurement is dependent on its reproducibility. Objects: To explore the reproducibility of the measurements derived from testing of the isokinetic strength of shoulder muscles in patients with tendinitis of the rotator cuff. Methods: A total of 20 patients with tendinitis of the rotator cuff participated in this study and were assessed twice in 1 week. Isokinetic testing was performed concentrically for shoulder flexors, abductors, and external rotators and eccentrically for the shoulder extensors, adductors, and internal rotators. The relative and absolute reproducibility of the peak torque (PT) and ratios were assessed using intra-class correlation coefficients (ICC), standard error of measurement (SEM), and minimal clinically important difference (MCID), respectively. Results: Overall, high to excellent ICC, clinically acceptable SEM and MCID values were obtained for the PT (ICC: .83-.95, SEM: 1.2%-9%, MCID: 3.4%-25%) and ratios (ICC: .85-.93, SEM: 5.1%-10%, MCID: 14.2%-27.6%). Conclusion: These findings suggest that isokinetic tests may be effectively utilized for the determination of shoulder strength profiles and appropriate position are recommended to perform test without pain in patients with tendinitis of the rotator cuff.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.717-722
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• 2002

The results of an experiment on the water purification of the porous concrete and its influence on the compressive strength are reported in this paper. Two different sizes of coarse aggregate of 5-10, and 10-20mm, and three absolute volume ratios of paste to aggregate of 30, 40 and 50 percent for a given size of aggregate were used. For the compressive strength, the concrete with the aggregate size of 5-10mm showed much higher strength than that with the aggregate size of 10-20mm. But, the compressive strength is higher when the ratio of paste to aggregate is smaller. In the water purification experiment, the amount of attached an organism on the porous concrete surface indirectly is examined by measuring the consumption of the Dissolved Oxygen (DO). The ability of the water purification is evaluated by the removal amount of the Total Phosphorus(T-P) and Total Nitrogen(T-N). The ability of the removal of the T-N and T-P in the test water is superior to a porous concrete with a smaller size of aggregate and a higher void content. These results are owing to a large specific surface area of the specimen. As a result, porous concrete using by-products has sufficient performance of water purification.

• Computers and Concrete
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• v.13 no.1
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• pp.17-30
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• 2014

This research presents the effect of various ground pozzolanic materials in blended cement concrete on the strength and chloride penetration resistance. An experimental investigation dealing with concrete incorporating ground fly ash (GFA), ground bottom ash (GBA) and ground rice husk ash (GRHA). The concretes were mixed by replacing each pozzolan to Ordinary Portland cement at levels of 0%, 10%, 20% and 40% by weight of binder. Three different water to cement ratios (0.35, 0.48 and 0.62) were used and type F superplasticizer was added to keep the required slump. Compressive strength and chloride permeability were determined at the ages of 28, 60, and 90 days. Furthermore, using this experimental database, linear and nonlinear multiple regression techniques were developed to construct a mathematical model of chloride permeability in concretes. Experimental results indicated that the incorporation of GFA, GBA and GRHA as a partial cement replacement significantly improved compressive strength and chloride penetration resistance. The chloride penetration of blended concrete continuously decreases with an increase in pozzolan content up to 40% of cement replacement and yields the highest reduction in the chloride permeability. Compressive strength of concretes incorporating with these pozzolans was obviously higher than those of the control concretes at all ages. In addition, the nonlinear technique gives a higher degree of accuracy than the linear regression based on statistical parameters and provides fairly reasonable absolute fraction of variance ($R^2$) of 0.974 and 0.960 for the charge passed and chloride penetration depth, respectively.

• Smart Structures and Systems
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• v.19 no.3
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• pp.335-340
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• 2017

Fiber Bragg grating (FBG) sensors are applied to structural health monitoring (SHM) in many areas due to their unique advantages such as ease of multiplexing and capability of absolute measurement. However, they are exposed to cyclic thermal load, generally in the temperature range of $-20^{\circ}C$ to $60^{\circ}C$, in railways during a long-term SHM and the cyclic thermal load can affect the mechanical strength of FBGs. In this paper, the effects of both cyclic thermal load and the reflectivity of FBGs on the mechanical strength are investigated though tension tests of FBG specimens after they are aged in a thermal chamber with temperature changes in a range from $-20^{\circ}C$ to $60^{\circ}C$ for 300 cycles. Results from tension tests reveal that the mechanical strength of FBGs decreases about 8% as the thermal cycle increases to 100 cycles; the mechanical strength then remains steady until 300 cycles. Otherwise, the mechanical strength of FBGs with reflectivity of 6dB (70%) and 10dB (90%) exhibits degradation values of about 6% and 12%, respectively, compared to that with reflectivity of 3dB (50%) at 300 cycles. SEM photos of the Bragg grating parts also show defects that cause their strength degradation. Consequently, it should be considered that mechanical strength of FBGs can be degraded by both thermal cycles and the reflectivity if the FBGs are exposed to repetitive thermal load during a long-term SHM.

• Advances in Computational Design
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• v.2 no.3
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• pp.225-240
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• 2017

This paper presents the application of multiple linear regression (MLR) and artificial neural network (ANN) techniques for developing the models to predict the unconfined compressive strength (UCS) and Brazilian tensile strength (BTS) of the fiber reinforced cement stabilized fly ash mixes. UCS and BTS is a highly nonlinear function of its constituents, thereby, making its modeling and prediction a difficult task. To establish relationship between the independent and dependent variables, a computational technique like ANN is employed which provides an efficient and easy approach to model the complex and nonlinear relationship. The data generated in the laboratory through systematic experimental programme for evaluating UCS and BTS of fiber reinforced cement fly ash mixes with respect to 7, 14 and 28 days' curing is used for development of the MLR and ANN model. The data used in the models is arranged in the format of four input parameters that cover the contents of cement and fibers along with maximum dry density (MDD) and optimum moisture contents (OMC), respectively and one dependent variable as unconfined compressive as well as Brazilian tensile strength. ANN models are trained and tested for various combinations of input and output data sets. Performance of networks is checked with the statistical error criteria of correlation coefficient (R), mean square error (MSE) and mean absolute error (MAE). It is observed that the ANN model predicts both, the unconfined compressive and Brazilian tensile, strength quite well in the form of R, RMSE and MAE. This study shows that as an alternative to classical modeling techniques, ANN approach can be used accurately for predicting the unconfined compressive strength and Brazilian tensile strength of fiber reinforced cement stabilized fly ash mixes.

• Advances in nano research
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• v.12 no.5
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• pp.515-527
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• 2022

The application of fibers in concrete obviously enhances the properties of concrete, also the application of natural fibers in concrete is raising due to the availability, low cost and environmentally friendly. Besides, predicting the mechanical properties of concrete in general and shear strength in particular is highly significant in concrete mixture with fiber nanocomposite reinforced concrete (FRC) in construction projects. Despite numerous studies in shear strength, determining this strength still needs more investigations. In this research, Adaptive Neuro-Fuzzy Inference System (ANFIS) have been employed to determine the strength of reinforced concrete with fiber. 180 empirical data were gathered from reliable literature to develop the methods. Models were developed, validated and their statistical results were compared through the root mean squared error (RMSE), determination coefficient (R²), mean absolute error (MAE) and Pearson correlation coefficient (r). Comparing the RMSE of PSO (0.8859) and ANFIS (0.6047) have emphasized the significant role of structural parameters on the shear strength of concrete, also effective depth, web width, and a clear depth rate are essential parameters in modeling the shear capacity of FRC. Considering the accuracy of our models in determining the shear strength of FRC, the outcomes have shown that the R² values of PSO (0.7487) was better than ANFIS (2.4048). Thus, in this research, PSO has demonstrated better performance than ANFIS in predicting the shear strength of FRC in case of accuracy and the least error ratio. Thus, PSO could be applied as a proper tool to maximum accuracy predict the shear strength of FRC.

• Computers and Concrete
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• v.14 no.5
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• pp.577-597
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• 2014

This paper aims to develop a prediction model for the hardened properties of waste LCD glass that is used in concrete by analyzing a series of laboratory test results, which were obtained in our previous study. We also summarized the testing results of the hardened properties of a variety of waste LCD glass concretes and discussed the effect of factors such as the water-binder ratio (w/b), waste glass content (G) and age (t) on the concrete compressive strength, flexural strength and ultrasonic pulse velocity. This study also applied a hyperbolic function, an exponential function and a power function in a non-linear regression analysis of multiple variables and established the prediction model that could consider the effect of the water-binder ratio (w/b), waste glass content (G) and age (t) on the concrete compressive strength, flexural strength and ultrasonic pulse velocity. Compared with the testing results, the statistical analysis shows that the coefficient of determination $R^2$ and the mean absolute percentage error (MAPE) were 0.93-0.96 and 5.4-8.4% for the compressive strength, 0.83-0.89 and 8.9-12.2% for the flexural strength and 0.87-0.89 and 1.8-2.2% for the ultrasonic pulse velocity, respectively. The proposed models are highly accurate in predicting the compressive strength, flexural strength and ultrasonic pulse velocity of waste LCD glass concrete. However, with other ranges of mixture parameters, the predicted models must be further studied.