• International Journal of Fuzzy Logic and Intelligent Systems
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• v.2 no.2
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• pp.115-121
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• 2002

This paper presents an evolutionary design of digital IIR filters using the genetic algorithm (GA) with modified genetic operators and real-valued encoding. Conventional digital IIR filter design methods involve algebraic transformations of the transfer function of an analog low-pass filter (LPF) that satisfies prescribed filter specifications. Other types of frequency-selective digital fillers as high-pass (HPF), band-pass (BPF), and band-stop (BSF) filters are obtained by appropriate transformations of a prototype low-pass filter. In the GA-based digital IIR filter design scheme, filter coefficients are represented as a set of real-valued genes in a chromosome. Each chromosome represents the structure and weights of an individual filter. GA directly finds the coefficients of the desired filter transfer function through genetic search fur given filter specifications of minimum filter order. Crossover and mutation operators are selected to ensure the stability of resulting IIR filters. Other types of filters can be found independently from the filter specifications, not from algebraic transformations.

• Steel and Composite Structures
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• v.6 no.2
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• pp.103-122
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• 2006

The capacity of tubular truss chords subjected to concentrated reaction forces in the vicinity of the open end (i.e., the bearing region) is not directly treated by existing design specifications; although capacity equations are promulgated for related tubular joint configurations. The lack of direct treatment of bearing capacity in existing design specifications seems to represent an unsatisfactory situation given the fact that connections very often control the design of long-span tubular structures comprised of members with slender cross-sections. The case of the simple-span overhead highway sign truss is studied, in which the bearing reaction is applied near the chord end. The present research is aimed at assessing the validity of adapting existing specifications' capacity equations from related cases so as to be applicable in determining design capacity in tubular truss bearing regions. These modified capacity equations are subsequently used in comparisons with full-scale experimental results obtained from testing carried out at the University of Pittsburgh.

• Magazine of the Korea Concrete Institute
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• v.20 no.6
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• pp.41-46
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• 2008

The bridge across Chambal River consists of two approach bridges and a cable stayed bridge with concrete girder and pylon. And the main bridge has been designed mainly based on AASHTO LRFD. This article covers design specifications from AASHTO LRFD, which are applied to load combinations and structural verification. And it also covers local standards applied in definition of loads such as live load, wind load, temperature, etc. In addition, the difference between applied design specifications and Korean standards is mentioned in this article briefly.

• Korean Journal of Computational Design and Engineering
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• v.15 no.2
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• pp.144-156
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• 2010

When existing parts are re-used for the development of a new product or business-to-business transactions, a method for searching parts from a part database that meets user's requirements is necessary. To this end, it is important to develop a part search method which is able to measure similarity between parts and user's input data with generality as well as robustness. In this paper, the authors suggest a method for measuring part similarity using ontology and multi-criteria decision making method and address its technical details. The proposed method ensures the interoperability with existing engineering information management systems, represents part specifications systematically, and has generality in the procedure for comparing part specifications. The case study for ejector pins having been conducted to demonstrate the proposed method is also discussed.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.465-470
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• 2001

Three-sided concrete culverts can be used to replace short span bridges and multiple sections(barrels) of four-sided concrete box culverts. ASTM Standards do not specify designs for four-sided concrete box culverts with span lengths exceeding 3.6m(12ft) nor do they discuss the three-sided concrete culverts. This paper describes the analysis and design of three-sided flat-top Precast reinforced concrete culverts with span length or 4m(14ft). Both AASHTO and Korean specifications were used to compare the main reinforcing steel. It is shown that the related provisions of Korean specifications result in more conservative design than those of AASHTO specifications.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.128-130
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• 2005

This paper proposes a modified IMC-PID controller that introduces controlling factor of the system identification to the standard IMC-PID controller in order to meet the design specifications such as gain, phase margin and maximum magnitude of sensitivity function in the frequency domain as well as the design specifications in time domain, settling, rising time and overshoot, and so on.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.63-66
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• 2002

This paper proposes a new identification method to be able to meet the design specifications. By introducing a controller factor in Pade apporximation of the previous system identification algorithm, relationships between system identification and design specifications are obtained through the Ziegler-Nickels tuning rule.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.193-199
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• 2001

In this study, the carbody design of the rubber tired AGT(Automated Guide-way Transit System) under development by KRRI was numerically analysed to evaluate its structural strength according to the standard specifications for Korean LRT (Light Rail Transit). The numerical results showed that the detail design of the carbody was strong enough to satisfy the specifications with respect to the axial compression strength, the vertical strength and the vertical stiffness(natural frequency). However, the carbody design had some problems on the fatigue strength by twist loadings. So, it was recommended that the carbody design should be modified to improve the twisting strength by reinforcing the front end structures.

• Tribology and Lubricants
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• v.39 no.5
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• pp.173-182
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• 2023

The composite planetary gear reducer, a power transmission component of armored vehicles, operates at a high torque and is used in severe environments such as mountain, gravel or unpaved roads. Therefore, they must be designed and manufactured to have high durability. To design such a planetary gear reducer, there are numerous specifications to validate, such as selecting the module and the number of teeth of each gear satisfied the requirements, and calculating gear specifications and durability strength. Because planetary gears constitute a combination of several gears, there are many restrictions and interferences in selecting the number of teeth and addendum modification coefficients, and designing the tooth shape. Developing an auto design program is necessary to design various planetary gears more conveniently and quickly. In this study, a planetary gear reducer design software, widely used in various machines and armored vehicles, was developed. This design software can automatically select the number of teeth and modules of the gears, calculate specifications and quickly evaluate its fatigue durability strength and scoring failure according to the planetary gear reducer design theory.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.3 s.303
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• pp.11-16
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• 2005

This paper proposed a new IMC-PID controller design method using the loop shaping method. By the application of the loop shaping method for IMC-PID controller which has only one design parameter and guarantees internal stability, we can not only consider such design specifications as gain margin, phases margin, and sensitivity functions but also obtain the loop gain by setting up the relationships between design specifications and design parameters. A systematic method to select design parameters of IMC-PID controller in order to meet the design specifications is suggested and its effectiveness is examined by the case study and analysis.