• The Journal of Advanced Prosthodontics
• /
• v.9 no.4
• /
• pp.244-251
• /
• 2017

PURPOSE. The purpose of this study was to determine fracture resistance and failure modes of three-unit fixed dental prostheses (FDPs) made of lithium disilicate pressed on zirconia (LZ), monolithic lithium disilicate (ML), and monolithic zirconia (MZ). MATERIALS AND METHODS. Co-Cr alloy three-unit metal FDPs model with maxillary first premolar and first molar abutments was fabricated. Three different FDPs groups, LZ, ML, and MZ, were prepared (n = 5 per group). The three-unit FDPs designs were identical for all specimens and cemented with resin cement on the prepared metal model. The region of pontic in FDPs was given 50,000 times of cyclic preloading at 2 Hz via dental chewing simulator and received a static load until fracture with universal testing machine fixed at $10^{\circ}$. The fracture resistance and mode of failure were recorded. Statistical analyses were performed using the Kruskal-Wallis test and Mann-Whitney U test with Bonferroni's correction (${\alpha}=0.05/3=0.017$). RESULTS. A significant difference in fracture resistance was found between LZ ($4943.87{\pm}1243.70N$) and ML ($2872.61{\pm}658.78N$) groups, as well as between ML and MZ ($4948.02{\pm}974.51N$) groups (P<.05), but no significant difference was found between LZ and MZ groups (P>.05). With regard to fracture pattern, there were three cases of veneer chipping and two interfacial fractures in LZ group, and complete fracture was observed in all the specimens of ML and MZ groups. CONCLUSION. Compared to monolithic lithium disilicate FDPs, monolithic zirconia FDPs and lithium disilicate glass ceramics pressed on zirconia-based FDPs showed superior fracture resistance while they manifested comparable fracture resistances.

• Journal of the Korea Society of Computer and Information
• /
• v.6 no.2
• /
• pp.116-122
• /
• 2001

A conventional multicast secure protocol. MVMRP, CBT is designed for a large scaled r protocol so the PIM-SM (protect Independent Multicst-Sparse Mode) routing protocol which small number of clients, long distance path among the hosts and shortest path routing chara weak point of require it's own Core tree and re-keying when the traffic is pass through the ro In this study, proposes a architect for a licit information secure of join/leave to all the user or on-service user. With proposed architect, subgroups for multicast secure group mana will be divided by RP (Rendezvous-Point) unit and each RP has a subgroup manager. As a result, the transmitting time is shortened because there is no need to data translation by group key on data sending and the whole architecture size is samller than the other multicast secure architecture.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2001.05a
• /
• pp.741-744
• /
• 2001

In this study, a OFDM mode, unlike traditional single carrier mode, is that a great number of carrier in multi-channel environment is transmitted by modulating objective Data parallel in order to execute high speed Data translation and make frequency orthogonal to offer high spectrum efficiency. As a result, this method is adopted to a variety of fields and is being actively studied. In this papers, the efficiency of OFDM wireless-communication systems is evaluated by modulation methods through computer simulation. M-PSK and M-QAM are used as modulation methods. The simulation is executed in a real channel and a virtual channel included multi-path, AWGN, Peak Power clipping, Frame Start Time Error As a result of simulation, it is confirmed that M-QAM method is superior to M-PSK in OFDM systems in terms of the transmission methods.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.6 no.4
• /
• pp.1024-1040
• /
• 2014

The theoretical background and a numerical solution procedure for a time domain hydroelastic code are presented in this paper. The code combines a VOF-based free surface flow solver with a flexible body motion solver where the body linear elastic deformation is described by a modal superposition of dry mode shapes expressed in a local floating frame of reference. These mode shapes can be obtained from any finite element code. The floating frame undergoes a pseudo rigid-body motion which allows for a large rigid body translation and rotation and fully preserves the coupling with the local structural deformation. The formulation relies on the ability of the flow solver to provide the total fluid action on the body including e.g. the viscous forces, hydrostatic and hydrodynamic forces, slamming forces and the fluid damping. A numerical simulation of a flexible barge is provided and compared to experiments to show that the VOF-based flow solver has this ability and the code has the potential to predict the global hydroelastic responses accurately.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.2
• /
• pp.251-256
• /
• 2001

In this study, a OFDM mode, unlike traditional single carrier mode, is that a great number of carrier in multi-channel environment is transmitted by modulating objective Data parallel in order to execute high speed Data translation and make frequency orthogonal to offer high spectrum efficiency As a result, this method is adopted to a variety of fields and is being actively studied. In this papers, the efficiency of OFDM wireless-communication systems is evaluated by modulation methods through computer simulation. M-PSK and M-QAM are used as modulation methods. The simulation is executed in a real channel and a virtual channel included multi-path, AWGN, Peak Power clipping, Frame Start Time Error. As a result of simulation, it is confirmed that M-OAM method is superior to M-PSK in OFDM systems in terms of the transmission methods.

• Proceedings of the KSR Conference
• /
• 2011.05a
• /
• pp.1321-1326
• /
• 2011

THE RAILWAY VEHICLE IS CONSISTS OF CARBODY, BOGIE AND WHEELSETS, EACH OF COMPONENTS IS CONNECTED WITH RIGID MASS, SPRING AND DAMPER. EACH OF COMPONENTS HAS TRANSLATION MOTIONS OF LONGITUDINAL (X AXIS), LATERAL (Y AXIS) AND VERTICAL (Z AXIS) DIRECTIONS, ROTATION MOTIONS OF X, Y, Z AXIS WHICH ARE NAMED ROLLING, PITCHING AND YAWING. THE VIBRATION MODE OF RAILWAY VEHICLE IS DIFFICULT TO FIND THE CHARACTERISTICS OF MOTION DURING THE OPERATION ON THE TRACK BECAUSE THESE HAPPEN TO INDEPENDENCE OR DUPLICATION MOTION CAUSED BY VEHICLE, WHEEL/RAIL AND TRACK IRREGULARITY ETC. IT IS NAMED AN ABNORMAL VIBRATION THAT THE VIBRATION, WHICH WAS PASSED THE PRIMARY AND SECONDARY SUSPENSION, IS AFFECTED TO THE PASSENGER WITHOUT DAMPING. THIS PAPER DESCRIBES AN EXPERIENCE EVALUATION TO FIND THE CAUSE OF AN ABNORMAL VIBRATION WHICH WAS HAPPEN AT OPERATING SPEED 60KPH ZONE DURING THE MAINLINE TEST.

• Journal of KSNVE
• /
• v.5 no.3
• /
• pp.327-335
• /
• 1995

The study deals with the vibration of a beam whose flexural and centroidal axes are not coincident. The elementary bending-twisting theory is employed to derive the equation of motion, in which the effects of rotary inertia are added to the bending displacements and the effects of warping are added to the twist. Bending translation is restricted to one direction so that one bending equation is used instead of two. The equations of motion are solved by using the boundary value problem. The exact natural frequencies are fund from the frequency equation, which is obtained from the condition that the homogeneous system of algebraic equations representing the spatial solution shall not yield a trivial solution. The orthogonal conditions are established, and the principal mode equations of forced vibration are derived. As an example, the cantilevered beam is chosen and the first some natural frequencies and their modal shapes are found.

• International Journal of Fluid Machinery and Systems
• /
• v.1 no.1
• /
• pp.169-180
• /
• 2008

As a major component of a power plant, a turbine generator must have sufficient reliability. Longer blades have lower natural frequency, thereby requiring that the design of the shaft and blade takes into account the coupling of the blade vibration mode, nodal diameter k=0 and k=1 with vibration of the shaft. The present work analyzes the coupling of the translation motion of the shaft with in-plane vibration of the blades with k=1 modes. At a rotational speed ${\Omega}_1=|{\omega}_s-{\omega}_b|$, the resonance of the blades has a relatively large amplitude. A violent coupled resonance was observed at a rotational speed ${\Omega}_2=|{\omega}_s+{\omega}_b|$. Resonance in blade vibration at ${\Omega}_1=|{\omega}_s-{\omega}_b|$ was experimentally confirmed.

• Asian-Australasian Journal of Animal Sciences
• /
• v.15 no.8
• /
• pp.1210-1214
• /
• 2002

The large and rapid changes of glucose utilization in lactating mammary tissue in response to changes in nutritional state must be largely related by external signal of insulin. This also must be related with the quantity and composition of the diet in vivo. To characterize the mode of gut extract protein with insulin, in vitro experiment was conducted with HC11 cells. The gut extract protein has not only the same effect as insulin alone but also the synergistic effect with insulin in 2-Deoxy[3H] glucose uptake. Although the gut extract did not modulates glucose uptake via increasing the rate of translation of the GLUT1 protein, northern blot analysis indicated that the gut extract protein increased the expression of GLUT1 mRNA by a threefold and also there was a dose-dependent increase in the expression of GLUT1 mRNA. The gut extract protein is therefore shown to be capable of modulating glucose uptake by transcription level with insulin in HC 11 cells.

• Korean Management Science Review
• /
• v.10 no.1
• /
• pp.59-80
• /
• 1993

Electronic data interchange (EDI) is a new technology of information communication which can make offices paperless. This study develop an EDI system to communicate informations among companies using computer systems. The system consists of five modules-document I/O, translation, system management, communication, and additional modules. The database of EDI documentation standards has been constructed by the table-driven method. The communication module provides three communication modes-RS232C, MODEM, and message handling system (MHS). The system performance has been improved by the method of data compression and data encryption which prevent the communication delay and illegal users. This EDI system can be used as a front-end, back-end, or stand-alone mode.