• Journal of electromagnetic engineering and science
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• v.13 no.4
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• pp.199-207
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• 2013

Meeting electromagnetic compatibility (EMC) requirements can be a significant challenge for engineers designing today's electronic devices. Traditional approaches rely heavily on EMC design rules. Unfortunately, these design rules aren't based on the specific EMC requirements for a particular device, and they don't usually take into account the specific function of the circuits or the many design details that will ultimately determine whether the device is compliant. This paper describes a design methodology that relates design decisions to the product's EMC requirements. The goal of performance-based EMC design is to ensure that electronic designs meet EMC requirements the first time the product is tested. More work needs to be done before this concept reaches its full potential, but electronic system designers can already derive significant benefit by applying this approach to products currently under development.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1220-1226
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• 2011

The purpose of this study is to assess the seismic performance of a reinforced concrete pier using ductility demand-based seismic design method and nonlinear earthquake analysis. A computer program named MIDAS/Civil(MIDAS IT,2009) for the analysis of the reinforced concrete pier was used. The bridge pier was designed by the ductility demand-based seismic design. In addition, a seismic performance was evaluated through both capacity spectrum method and nonlinear time history method. In order to determine the seismic performance of the bridge pier, the maximum response values from the capacity spectrum method and nonlinear time history analysis were compared each other.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.1
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• pp.17-32
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• 1995

The objective of this study is to develop a general design and performance evaluation model for the system designers in the initial design phase of the integrated automatic manufacturing system based on the RAM(Reliability, Availability and Maintainability) and life cycle cost(LCC). The methodology proposed in this research includes the following two stages. First, a deterministic approach to the solution of optimal work station arrangement for the initial system configuration is considered under the assumption that the system availability is one(no failure and maintenance), and then a stochastic simulation model based on RAM and LCC is developed. Using the results of these two stage simulation, a system performance index(SPI) was developed for the performance evaluation of the proposed system. Also a computer program is developed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11C
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• pp.907-910
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• 2010

This paper presents the design of block lengths for irregular low-density parity-check (LDPC) codes based on the maximum variable degree $d_{{\upsilon},max}$. To design a block length, the performance degradation of belief-propagation (BP) decoding performance from upper bounds on the maximum likelihood (ML) decoding performance is used as an important factor. Since for large block lengths, the performance of irregular LDPC codes is very close to the Shannon limit, we focus on moderate block lengths ($5{\times}10^2\;{\leq}\;N\;{\leq}\;4{\times}10^3$). Given degree distributions, the purpose of our paper is to find proper block lengths based on the maximum variable degree $d_{{\upsilon},max}$. We also present some simulation results which show how a block length can be optimized.

• Steel and Composite Structures
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• v.16 no.4
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• pp.357-374
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• 2014

The design basis is being shifted from strength to deformation in modern performance-based design codes. This paper presents a practical method for optimization of eccentrically braced steel frames, based on the concept of uniform deformation theory (UDT). This is done by gradually shifting inefficient material from strong parts of the structure to the weak areas until a state of uniform deformation is achieved. In the first part of this paper, UDT is implemented on 3, 5 and 10 story eccentrically braced frames (EBF) subjected to 12 earthquake records representing the design spectrum of ASCE/SEI 7-10. Subsequently, the optimum strength-distribution patterns corresponding to these excitations are determined, and compared with four other loading patterns. Since the optimized frames have uniform distribution of deformation, they undergo less damage in comparison with code-based designed structures while having minimum structural weight. For further investigation, the 10 story EBF is redesigned using four different loading patterns and subjected to 12 earthquake excitations. Then a comparison is made between link rotations of each model and those belonging to the optimized one which revealed that the optimized EBF behaves generally better than those designed by other loading patterns. Finally, efficiency of each loading pattern is evaluated and the best one is determined.

• Earthquakes and Structures
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• v.13 no.5
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• pp.443-454
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• 2017

When eccentrically braced steel frames (EBFs) are in the desired failure mode, links yield at each layer and column bases appear plastically hinged. Traditional design methods cannot accurately predict the inelastic behavior of structures owing to the use of capacity-based design theory. This paper proposes the use of performance-based seismic design (PBSD) method for planning eccentrically braced frames. PBSD can predict and control inelastic deformation of structures by target drift and failure mode. In buildings designed via this process, all links dissipate energy in the rare event of an earthquake, while other members remain in elastic state, and as the story drift is uniform along the structure height, weak layers will be avoided. In this condition, eccentrically braced frames may be more easily rehabilitated after the effects of an earthquake. The effectiveness of the proposed method is illustrated through a sample case study of ten-story K-type EBFs and Y- type EBFs buildings, and is validated by pushover analysis and dynamic analysis. The ultimate state of frames designed by the proposed method will fail in the desired failure mode. That is, inelastic deformation of structure mainly occurs in links; each layer of links involved dissipates energy, and weak layers do not exist in the structure. The PBSD method can provide a reference for structural design of eccentrically braced steel frames.

• Advances in concrete construction
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• v.17 no.4
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• pp.221-232
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• 2024

As a supplemental energy dissipation device, friction dampers are widely employed to augment the behaviour of buildings under seismic forces. In the current work, a methodology for the design of the friction damping system of RC frame buildings is offered using performance-based plastic design (PBPD) method. Here 2% of maximum interstorey drift ratio for life safety (LS) level is taken into account as a target drift to estimate the design base shear. In this approach, the distribution of friction damper is determined based on the hysteretic energy demand of that storey. Two frames, five storey three bay (5S3B) and eight storey three bay (8S3B) RC frame building with and without friction damping systems are also taken up for the investigation. The suggested design approach is validated by the nonlinear time history analysis (NLTHA) procedure. Inter story drift ratio (ISDR) and storey displacement, which are the more closely related to structural damage during seismic excitation are evaluated. The results show that the friction damping system on a retrofitted RC frame building performs effectively under seismic excitations and that storey displacement and ISDR are within the limit at moderate and high seismic intensities.

• Journal of Applied Reliability
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• v.10 no.1
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• pp.1-9
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• 2010

In general, the performance of a component degrades as time goes by and failure of a component occurs when the performance degradation reaches a pre-specified level. It is difficult to obtain the failure time distribution data or the necessary number of failure data especially for the metal or machine part. Thus, a design of reliability qualification test based on performance distribution is more effective than failure time distribution. In this study, a performance-based reliability qualification test is developed and a numerical example is provided to illustrate the use of the developed reliability qualification test. This approach could be applied to many kinds of metal or machine part whose magnitude of strength could not be evaluated during at any random points but judgement can be made by only failure of the part. Besides, it is also possible that any parts which have a similar failure characteristics could be applicable to the developed reliability qualification test.

• Structural Engineering and Mechanics
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• v.41 no.2
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• pp.243-262
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• 2012

Nonlinear static analysis as an essential part of performance based design is now widely used especially at design offices because of its simplicity and ability to predict seismic demands on inelastic response of buildings. Since the accuracy of nonlinear static procedures (NSP) to predict seismic demands of buildings affects directly on the entire performance based design procedure, therefore lots of research has been performed on the area of evaluation of these procedures. In this paper, one of the popular NSP, FEMA356, is evaluated and compared with modal pushover analysis. The ability of these procedures to simulate seismic demands in a set of reinforced concrete (RC) buildings is explored with two level of base acceleration through a comparison with benchmark results determined from a set of nonlinear time history analyses. According to the results of this study, the modal pushover analysis procedure estimates seismic demands of buildings like inter story drifts and hinges plastic rotations more accurate than FEMA356 procedure.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.32-39
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• 2000

Probabilistic structural design optimization, which is characterized by the so-called probabilistic. constraints which introduce permissible probability of violation, is preferred to deterministic design optimization since unpredictable inherent uncertainties and randomness in structural and environmental properties are to be taken quantitatively into account by probabilistic design optimization. In this paper, the well-known reliability index based MPFP(Most Probable Failure Point) search approach and the newly introduced target performance measure based MPTP(Minimum Performance Target Point) search approach are summarized and compared. The present comparison focuses on the number of iterations required for the estimation of probabilistic constraints and a technique for improvement which removes exhaustive iterations is presented as well. A 10 bar truss problem is examined for this.