• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.343-358
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• 2008

Piles of a bridge pier are connected with a column through a pile cap(footing). Behavior of the pile foundation can be different according to the connection method between piles and the pile cap. This difference causes a change of the design method. Connection methods between pile heads and the pile cap are divided into two groups ; rigid connections and hinge connections. KHBDC(Korea Highway Bridge Design Code) has specified to use rigid connection method for the highway bridge. In the rigid connection method, maximum bending moment of a pile occurs at the pile head and this helps the pile to prevent the excessive displacement. Rigid methods are also good to improve the seismic performance. However some specifications prescribe that conservative results through investigations for both the fixed-head condition and the free-head condition should be reflected in the design. This statement may induce an over-estimated design for the bridge which have very good quality structures with casing covered drilled shafts and the PC-house contained pile cap. Because the assumption of free-head conditions (hinge connections) are unreal for the elevated pile cap system with multiple piles of the long span sea-crossing bridges. On the other hand, elastic displacement method to evaluate the pile reactions under the pile cap is not suitable for this type of bridges due to impractical assumptions. So, full modeling techniques which analyze the superstructure and the substructure simultaneously should be performed. Loads and stress state of the very large diameter drilled shaft and the pile cap for Incheon Bridge which will the longest bridge in Korea were investigated through the full modeling for rigid connection conditions.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.2
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• pp.308-329
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• 1997

A lot of the research paper was reported about the result of influence of IMC (Intra-mobile connector) in the IMZ implant placed solely in the alveolar bone, but reports about the effect of IMC on functional load at state of connecting with natural teeth ere rare. The major propose of this study was find the mechanical character of IMC itself by using the finite element analysis program after simulated variance of condition connected with the natural teeth and implant on funcional load. When first and second premolar was lost, IMZ implant was placed with a diameter of 3.3mm and a length of 13mm with IMC in second premolar area. Rigid connection was done and the non-figid connention was located on the female part of the canine abutment and the implant respectively and then both the infraocclusion of $30{\mu}m$ and the non-infraocclusion under the load of 40kg applied to the portion of the natural teeth, the pontic and the implant. The displacement and the stress of it was estimated and analyzed IMC itself of the rigid connection and the non-rigid connection was grouped. The following result were obtained. 1. In all groups, the displacement of Y-axis was greater than that of X-axis and the aspect of displacement showed that IMC was displaced downward and to the center. 2. There was no differences in the displacement of IMC regardless of the connection type. 3. In the displacement of IMC, I 4 was the least, I 1 and I 3 are similar and I 2 was the greatest. 4. There was no differences in the peak value of maximal stress of IMC regardless of the connection type. 5. In the peak value of maximal stress of IMC, I 4 was the least, I 1 and I 3 were similar, and I 2 was the largest.

• Journal of the Korean Ceramic Society
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• v.29 no.11
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• pp.855-862
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• 1992

Thermoelectric power, electrical conductivity and Hall effect were measured, as functions of temperature in the range of 100 to 600 K, on polycrystalline Bi4/3Sb2/3Te3 which had been prepared via uniaxial hot-pressing at different temperatures in the range of 373 K to 773 K, aiming at searching a profitable processing route to a polycrystalline thermoelectric material, a promising, viable alternative to a single crystalline one. It was found that, with increasing temperature of pressing under a fixed pressure, the material, normally a p-type prior to being hot-pressed, underwent a transition to n-type. This transition was confirmed to be due to plastic deformation during hot-pressing and interpreted as being attributed to the change of the major ionic defect BiTe' into TeBi˙at temperature high enough for structure elements mobility. Thermoelectric figure-of-merit of the hot-pressed material was discussed in connection with the p-n transition in addition to microstructure.

• Steel and Composite Structures
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• v.10 no.6
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• pp.541-561
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• 2010

This paper presents finite element analyses, experimental measurements and finite element model updating of an arch type steel laboratory bridge model using semi-rigid connections. The laboratory bridge model is a single span and fixed base structure with a length of 6.1 m and width of 1.1m. The height of the bridge column is 0.85 m and the maximum arch height is 0.95 m. Firstly, a finite element model of the bridge is created in SAP2000 program and analytical dynamic characteristics such as natural frequencies and mode shapes are determined. Then, experimental measurements using ambient vibration tests are performed and dynamic characteristics (natural frequencies, mode shapes and damping ratios) are obtained. Ambient vibration tests are performed under natural excitations such as wind and small impact effects. The Enhanced Frequency Domain Decomposition method in the frequency domain and the Stochastic Subspace Identification method in the time domain are used to extract the dynamic characteristics. Then the finite element model of the bridge is updated using linear elastic rotational springs in the supports and structural element connections to minimize the differences between analytically and experimentally estimated dynamic characteristics. At the end of the study, maximum differences in the natural frequencies are reduced on average from 47% to 2.6%. It is seen that there is a good agreement between analytical and experimental results after finite element model updating. Also, connection percentages of the all structural elements to joints are determined depending on the rotational spring stiffness.

• Steel and Composite Structures
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• v.1 no.4
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• pp.459-480
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• 2001

The damage suffered by steel structures during the Northridge (1994) and Kobe (1995) earthquakes indicates that the fully restrained (FR) connections in steel frames did not behave as expected. Consequently, researchers began studying other possibilities, including making the connections more flexible, to reduce the risk of damage from seismic loading. Recent experimental and analytical investigations pointed out that the seismic response of steel frames with partially restrained (PR) connections might be superior to that of similar frames with FR connections since the energy dissipation at PR connections could be significant. This beneficial effect has not yet been fully quantified analytically. Thus, the dissipation of energy at PR connections needs to be considered in analytical evaluations, in addition to the dissipation of energy due to viscous damping and at plastic hinges (if they form). An algorithm is developed and verified by the authors to estimate the nonlinear time-domain dynamic response of steel frames with PR connections. The verified algorithm is then used to quantify the major sources of energy dissipation and their effect on the overall structural response in terms of the maximum base shear and the maximum top displacement. The results indicate that the dissipation of energy at PR connections is comparable to that dissipated by viscous damping and at plastic hinges. In general, the maximum total base shear significantly increases with an increase in the connection stiffness. On the other hand, the maximum top lateral displacement $U_{max}$ does not always increase as the connection stiffness decreases. Energy dissipation is considerably influenced by the stiffness of a connection, defined in terms of the T ratio, i.e., the ratio of the moment the connection would have to carry according to beam line theory (Disque 1964) and the fixed end moment of the girder. A connection with a T ratio of at least 0.9 is considered to be fully restrained. The energy dissipation behavior may be quite different for a frame with FR connections with a T ratio of 1.0 compared to when the T ratio is 0.9. Thus, for nonlinear seismic analysis, a T ratio of at least 0.9 should not be considered to be an FR connection. The study quantitatively confirms the general observations made in experimental results for frames with PR connections. Proper consideration of the PR connection stiffness and other dynamic properties are essential to predict dynamic behavior, no matter how difficult the analysis procedure becomes. Any simplified approach may need to be calibrated using this type of detailed analytical study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2399-2405
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• 2014

A fish-bone type bridge is vulnerable to the torsional behavior due to the single girder system with planar zigzag conformation. The fixed connecting area between the girder and pier is the special weak point because the torsional load creates excessive stress concentration. Therefore, the method to reduce the stress concentration is required. In this study, the reduction efficiency of various reinforcing types to reduce the excessive stress occurring at the connecting area is evaluated by using numerical analyses.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.376-379
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• 1996

Synthesis for qualitative analysis in connection with quantitative analysis from the pinch design method, EVOP and Operations Research is proposed for the optimal synthesis of heat exchanger networks, that is through of the transportation model of the linear programming for synthesizing chemical processing systems, to determine the location of pinch points, the stream matches and the corresponding heat flowrate exchanged at each match. In the second place, according to the optimization, the optimal design of heat transfer enhancement is carried on a fixed optimum heat exchanger network structure, in which this design determines optimal operational parameters and the chosen type of heat exchangers as well. Finally, the method of this paper is applied to the study of the optimal synthetic design of heat exchanger network of constant-decompress distillation plants.

• Journal of applied mathematics & informatics
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• v.4 no.1
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• pp.83-108
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• 1997

Chebysheff-Halley methods are probably the best known cubically convergent iterative procedures for solving nonlinear equa-tions. These methods however require an evaluation of the second Frechet-derivative at each step which means a number of function eval-uations proportional to the cube of the dimension of the space. To re-duce the computational cost we replace the second Frechet derivative with a fixed bounded bilinear operator. Using the majorant method and Newton-Kantorovich type hypotheses we provide sufficient condi-tions for the convergence of our method to a locally unique solution of a nonlinear equation in Banach space. Our method is shown to be faster than Newton's method under the same computational cost. Finally we apply our results to solve nonlinear integral equations appearing in radiative transfer in connection with the problem of determination of the angular distribution of the radiant-flux emerging from a plane radiation field.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.5
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• pp.76-85
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• 1999

The intuitive understanding of the dynamic pattern generation in asymmetric networks may be useful for developing models of dynamic information processing. In this paper, dynamic behavior of the cyclic connection neural network, in which each neuron is connected only to its nearest neurons with binary synaptic weights of $\pm$ 1, has been investigated. Simulation results show that dynamic behavior of the network can be classified into only three categories: fixed points, limit cycles with basin and limit cycles with no basin. Furthermore, the number and the type of limit cycles generated by the networks have been derived through analytical method. The sufficient conditions for a state vector of $n$-neuron network to produce a limit cycle of $n$- or 2$n$-period are also given. The results show that the estimated number of limit cycles is an exponential function of $n$. On the basis of this study, cyclic connection neural network may be capable of storing a large number of dynamic information.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.283-283
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• 2010

Smart street light controller is a product with advance micro controller base for energy saving in conventional street lighting systems. Intelligent Street light controller are specially developed for automation and energy saving in conventional street light systems and lighting systems. It is so designed that it operates on sunrise & sun set timings according to longitude of particular location with facilitate to set month wise civil twilight timings to cope up with all seasons. Dimming (Power down) mode selection switch on/off at fixed times with relay or contactor. Night dimming, staggering and intelligent control reduces burn hours and increases the lifetime of lamps with about 30% and low annual operating cost type base are among the most inexpensive wireless technologies available. Low initial costs As PLC wireless, there is no need to establish cable connection.