• Smart Structures and Systems
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• v.17 no.4
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• pp.593-610
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• 2016

In this study, an innovative and smart glass fiber-reinforced polymer (GFRP) hybrid bar was developed for stronger durability of concrete structures. As comparing with the conventional GFRP bar, the smart GFRP Hybrid bar can promise to enhance the modulus of elasticity so that it makes the cracking reduced than the case when the conventional GFRP bar is used. Besides, the GFRP Hybrid bar can effectively resist the corrosion of conventional steel bar by the GFRP outer surface on the steel bar. In order to verify the bond performance of the GFRP hybrid bar for structural reinforcement, uniaxial pull-out test was conducted. The variables were the bar diameter and the number of strands and pitch of the fiber ribs. Tensile tests showed a excellent increase in the modulus of elasticity, 152.1 GPa, as compared to that of the pure GFRP bar (50 GPa). The stress-strain curve was bi-linear, so that the ductile performance could be obtained. For the bond test, the entire GFRP hybrid bar test specimens failed in concrete splitting due to higher shear strength resulting in concrete crushing as a function of bar deformation. Investigation revealed that an increase in the number of strands of fiber ribs enhanced the bond strength, and the pitch guaranteed the bond strength of 19.1 mm diameter hybrid bar with 15.9 mm diameter of core section of deformed steel the ACI 440 1R-15 equation is regarded as more suitable for predicting the bond strength of GFRP hybrid bars, whereas the CSA S806-12 prediction is considered too conservative and is largely influenced by the bar diameter. For further study, various geometrical and material properties such as concrete cover, cross-sectional ratio, and surface treatment should be considered.

• Journal of The Korean Astronomical Society
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• v.34 no.4
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• pp.255-259
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• 2001

PMDSPH is a combined 3D particle-mesh and SPH code aimed to simulate the self-consistent dynamical evolution of spiral galaxies including live stellar and collisionless dark matter components, as well as an isothermal gas component. This paper describes some aspects of this code and shows how its application to the Milky Way helps to recover the gas flow within the Galactic bar region from the observed HI and CO longitude-velocity distributions.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.1
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• pp.85-93
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• 2013

In order to make a more reasonable evaluation on the stiffness of the high-strength mortar-filled sleeve bar splices under cyclic loading, we investigated and analyzed the existing experiment data of 106 full-sized reinforcing bar splices with test variables such as compressive strength of mortar, development length of reinforcement and sleeve type, etc. The following were found: 1) If mortar and the reinforcement development length with $f_{g^*}$(L/d) of more than 340 is used, the cast iron sleeve bar splices for SD350 and SD400 will have the stiffness of higher than A class of the AIJ code. 2) If mortar and the reinforcement development length with $f_{g^*}$(L/d) of more than 400 is used, the cast iron sleeve splices and pipe sleeve splices for SD500 will have the stiffness of higher than A class of the AIJ code.

• Journal of the Korea Society of Computer and Information
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• v.16 no.11
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• pp.113-122
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• 2011

In this paper, we propose an iPhone application that allows the user to pay for donations using the camera, GPS and call functions of the iPhone. As iOS version 3.0 allows the iPhone camera to detect and read bar codes and QR codes, the proposed application uses such codes to identify a product the user wishes to donation. After determining the user's location using the iPhone GPS function, the application can then perform a navigation task that guides the user to a suitable shop or store where the user can make his or her donation. In addition, the application offers an ARS call function that allows the user to make a direct donation, even if the user does not know the telephone number for making such donations. Therefore, the proposed application provides an easy means for the user to pay for donations directly or indirectly.

• Journal of the Korea Institute of Building Construction
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• v.8 no.1
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• pp.83-90
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• 2008

The reinforcing steel process is composed of the development of placing drawing, cutting and bending, and the placement and fabrication of the reinforcement, and is participated in by reinforcement detailer, the fabricator and placer. Because the reinforcing steel process-from estimating and rebar detailing, to production, material tracking, billing, and general accounting-is conducted by many participant, reinforcement details based on building code and reinforcing bar detailing standards are essential. The process, however, holds some problems. Building code has been revised recently, and the utilization of placing drawings was proved to be low, and the reinforcement estimating in early stage of the process is below what is required for placement. Therefore, in this study, a survey was conducted to the reinforcement detailer, the fabricator and placer of domestic construction industry. According to the analysis of the survey, the reinforcement details on site was not standardized. The improvement in reinforcing steel detailing standards was sought by analyzing the results of the survey including reinforcement constructability.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.10
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• pp.1977-1985
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• 2007

The character recognition technique is one of the artificial intelligence and has been widely applied in the automated system robot HCI(Human Computer Interaction), etc. This paper introduces the character set and the representative character that can be used in the recognition of the mage ROI. The character codes in this ROI include the digit, symbol, English and Hereat etc. We proposed the efficient multi-classifier structure by combining the small-size classifiers hierarchically. Moreover, we generated each small-size classifiers by delta-bar-delta learning algorithm. We tested the performance with various kinds of images and achieved the accuracy of 99%. The proposed multi-classifier showed the efficiency and the reliability for the mixed character code set.

• Journal of the Korean Society of Industry Convergence
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• v.9 no.1
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• pp.21-27
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• 2006

The laminar burning velocity was measured using a spherical combustion bomb with central ignition. Mixtures with equivalence ratio between 0.6 and 1.2, were tested. The computation was carried out for the burning velocity using premix code of Chemkin program under the unburned gas pressure of 0.5bar-30bar and temperature of 300K-700K at ${\Phi}1.0$. The results showed little difference between these two methods. The burning velocity was decreased by increasing the pressure and increased by increasing the temperature. The burning velocity was predicted by using the following equations $$S_L(m/s) = S_{st}(T/300)^{1.85}(P)^{-0.45}$$ $$(0.5bar{\leq}P{\leq}30bar,\;300K{\leq}T{\leq}700K)$$).

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.903-906
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• 2001

The objective of this experimental study was to understand the effect of horizontal shear bar on the shear behavior of R.C. deep beams. Therefore, in the test program, the horizontal shear bar ratio($\rho_{sh}$) and shear span-to-overall depth ratio(a/h) are considered as two main variables. Test results indicate that for deep beams with a/h equal to 1.0, horizontal shear bar is less efficient in restricting the diagonal crack width development and enhancing the ultimate shear strength. So, it can be concluded that shear resistance of horizontal shear bar is related to a/h rather than clear span-to-effective depth ratio($l_{n}$/d) recommended in ACI code.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.10a
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• pp.319-324
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• 1994

Bond test was carried out to assess the effect of several variables on bond characteristics between reinforcing bar and concrete. Key variables are concrete compressive strength(low, medium high, and ultra-high), bar diameter(13mm and 22mm), and concrete cover(25mm; 1-inch, 38mm; 1.5-inch, and 51mm; 2-inch). Confining effect and bar spacing are not taken into account. Thirty-two specimens subjected to uniaxial tension were tested under hypothesis uniform bond stress distribution along the reinforcing bar embeded in concrete. Test results(ultimate bond stress) were compared with bond and development provisions of the ACI building Code(ACl 318-89) and local bond stress versus slip relationship diagram represented to show effect of the above variables.

• The Journal of Korea Robotics Society
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• v.6 no.1
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• pp.49-57
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• 2011

In many industries, the accurate and quick checking of goods in storage is of great importance. Most today's inventory checking is based on bar code scanning, but the relative position between a bar code and an optical scanner should be maintained in close distance and proper angle for the successful scanning. This requirement makes it difficult to fully automate the inventory information/control systems. The use of RFID technology can be a solution for overcoming this problem. The mobile robot presented in this paper is equipped with an RFID tag scanning system, that automates the otherwise manual or semi-automatic inventory checking process. We designed the robot system in a quite practical approach, and the developed system is close to the commercialization stage. In our experiments, the robot could collect information of goods stacked on shelves autonomously without any failure and maintain corresponding database while it navigated predefined paths between the shelves using vision.