• Computational Structural Engineering : An International Journal
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• v.1 no.2
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• pp.97-106
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• 2001

Safety and serviceability of a planar steel frame are assessed. Attention is turned to the individual main steps in the assessment procedure, i.e., to the definition of loads, selection of transformation model, determination of the response of the structure to the loading, and to the definition of the limiting values (considering safely and serviceability of the structure). The potential of the method using direct Monte Carlo technique as a powerful tool is emphasized.

• International Journal of High-Rise Buildings
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• v.7 no.4
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• pp.343-362
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• 2018

A simplified spring connection modelling approach for steel flush endplate beam-to-column connections in fire has been developed to enable realistic behaviour of connections to be incorporated into full-scale frame analyses at elevated temperature. Due to its simplicity and reliability, the proposed approach permits full-scale high-temperature frame analysis to be conducted without high computational cost. The proposed simplified spring connection modelling approach has been used to investigate the influence of connection ductility (both axial and rotational) on frame behaviour in fire. 2D steel and 3D composite frames with a range of beam spans were modelled to aid the understanding of the differences in frame response in fire where the beam-to-column connections have different axial and rotational ductility assumptions. The modelling results highlight that adopting the conventional rigid or pinned connection assumptions does not permit the axial forces acting on the connections to be accurately predicted, since the axial ductility of the connection is completely neglected when the rotational ductility is either fully restrained or free. By accounting for realistic axial and rotational ductilities of beam-to-column connections, the frame response in fire can be predicted more accurately, which is advantageous in performance-based structural fire engineering design.

• Journal of the Korean Society of Systems Engineering
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• v.5 no.1
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• pp.43-48
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• 2009

Korean Tilting trains have been tested on conventional lines since the beginning of 2007 for evaluating its reliability. We achieved some major performance tests which are the maximum operation speed, 180km/h test and the maximum curves increasing speed, over 30 percentage comparing with non-tilling operation train. In order to analysis reliability data of tilting train, we have used the special system engineering frame with interfacing between component suppliers effectively. And also we have developed the data aquisition system which consists of monitor, sensors and depot computer etc. As a results of calculation, until now we realized that the reliability are getting more increasing than starting point of running field test.

• Journal of the Semiconductor & Display Technology
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• v.20 no.4
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• pp.141-145
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• 2021

The brightness of the Organic Light Emitting Diode (OLED) display is controlled by thin-film transistors (TFTs). Regardless of the materials and the structures of TFTs, an OLED suffers from the instable threshold voltage (V_th) of a TFT during operation. When designing an OLED pixel with circuit simulation tool such as SPICE, a designer needs to take V_th shift into account to improve the reliability of the circuit and various compensation methods have been proposed. In this paper, the effect of the compensation circuits from two typical OLED pixel circuits proposed in the literature are studied by the transient simulation with a SPICE tool in which the stretched-exponential time dependent V_th shift function is implemented. The simulation results show that the compensation circuits improve the reliability at the beginning of each frame, but V_th shifts from all TFTs in a pixel need to be considered to improve long-time reliability.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.6
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• pp.117-126
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• 2010

In the case of failure images with controlling lighting like backlighting and excessive frontlinghting, the compensation scheme for a specific area in an image is required. The interested region is first selected by user in our method to compensate the first frame. Then we define the matching function of brightness and energy function is proposed with weight of matching function and the relationship among the neighbors. Finally, the energy is minimized by the graph-cut algorithm to compensate the brightness of the first frame. Other frames are straightforwardly compensated using the results of the first frame. The brightness variations of the previous frame is transmitted to the next frame via motion vectors. The reliability of the brightness variation is calculated based on the motion vector reliability. Video compensation result is achieved by the process of the image case. Simulation show that the proposed algorithm provides more natural results than the conventional algorithms.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.5
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• pp.76-84
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• 2021

In this study, an optimal stiffness model of the C-frame, which was supporting the mold and tool load, was proposed to obtain quality self-piercing riveting (SPR) joining. First, the load path acting on the C-frame structure was identified using topology optimization. Then, a final suggested model was proposed based on the load path results. Stiffness and strength analyses were performed for a rivet pressing force of 7.3 [t] to compare the design performance of the final proposed model with that of the initial model. Moreover, to examine the reliability of continuous and repeated processes, vibration analysis was performed and the dynamic stiffness of the final proposed model was reviewed. Additionally, fatigue analysis was performed to ascertain the fatigue characteristics due to simple repetitive loading. Finally, stiffness test was performed for the final proposed model to verify the analysis results. The obtained results differed from the analysis result by 2.9%. Consequently, the performance of the final proposed model was superior to that of the initial model with respect to not only the SPR fastening quality but also the reliability of continuous and repetitive processes.

• The KIPS Transactions:PartC
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• v.8C no.1
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• pp.16-22
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• 2001

There are several traditional factors of software quality. Some of them are such as correctness, reliability, efficiency, compatibility, portability, etc. In addition to them, security is required as another factor of software quality nowadays because some application programs are used as a way to attack information systems by stack frame manipulation. Each processor has its own peculiar stack frame mechanism and C language uses the characteristics of them. This paper explains the concept of security problem caused by stack frame manipulation, and the stack frame mechanism of Pentium, Alpha and SP ARC processor in detail. And then it examines the effect of stack frame mechanism on the security of programs in C language.

• Steel and Composite Structures
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• v.21 no.4
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• pp.805-827
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• 2016

A new type of precast CFST column to RC beam braced frame is proposed in this paper. A series of shake table tests were conducted to excite a one-third scale six-story model for investigating the global seismic performance of this type of structure against earthquake actions. Particular emphasis was given to its dynamic property, global seismic responses and failure path. Correspondingly, a numerical model built on the basis of fiber-beam-element model, multi-layer shell model and element-deactivation method was developed to simulate the seismic performance of the prototype structure. Numerical results were compared with the measured values from shake table tests to verify the validity and reliability of the numerical model. The results demonstrated that the proposed novel precast CFST column to RC beam braced frame performs excellently under strong earthquake excitations; the "strong CFST column-weak RC beam" and "strong connection-weak member" anti-seismic design principles can be easily achieved; the maximum deflections of precast CFSTC-RCB braced frame satisfied the deflection limitations proposed in national code; the numerical model can properly simulate the dynamic property and responses of the precast CFSTC-RCB braced frame that are highly concerned in engineering practice.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.3
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• pp.523-541
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• 2011

In current IEEE 802.11 wireless LAN, every unicast transmission requires an ACK from the receiver for reliability, though it consumes energy and bandwidth. There have been studies to remove or reduce ACK overhead, especially for energy efficiency. However none of them are practically used now. This paper introduces a noble method of selective unacknowledged transmission, where skipping an ACK is dynamically decided frame by frame. Utilizing the fact that a multicast frame is transmitted without accompanying an ACK in 802.11, the basic unacknowledged transmission is achieved simply by transforming the destination address of a frame to a multicast address. Since removing ACK is inherently more efficient but less strict, its practical profit is dependent on traffic characteristics of a frame as well as network error conditions. To figure out the selective conditions, energy and performance implications of unacknowledged transmission have been explored. Extensive experiments show that energy consumption is almost always reduced, but performance may be dropped especially when TCP exchanges long data with a long distance node through a poor wireless link. An experiment with a well-known traffic model shows that selective unacknowledged transmission gives energy saving with comparable performance.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.1
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• pp.116-124
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• 2021

In this study, the reliability of vehicle frames employed in small electric road sweepers was assessed through durability testing. The frames were tested under three conditions, whereby mechanical loads were applied to (1) the entire frame, (2) the front frame, and (3) the rear frame. The strain distributions in the loaded frames were determined through a combination of direct strain gauge measurements and supplementary numerical analysis. While subtle differences were observed between the experimental and numerical analyses, both methods successfully yielded comparable deformation patterns. Thus, the dependence of stress distribution and the state of the frame on loading conditions could be fully identified through our combined structural and numerical analysis.