• Advances in Computational Design
• /
• v.2 no.4
• /
• pp.283-291
• /
• 2017

High frequency full bridge series resonant inverters have become increasingly popular among power supply designers. One of the most important parameter for a High Frequency Full Bridge Series Resonant Inverter is optimal coil design. The optimal coil designing procedure is not a easy task. This paper deals with the New Approach to Optimal Design Procedure for a Real-time High Frequency Full Bridge Series Resonant Inverter in Induction Heating Equipment devices. A new design to experimental modelling of the physical properties and a practical power input simulation process for the non-sinusoidal input waveform is accepted. The design sensitivity analysis with Levenberg-Marquardt technique is used for the optimal design process. The proposed technique is applied to an Induction Heating Equipment devices model and the result is verified by real-time experiment. The main advantages of this design technique is to achieve more accurate temperature control with a huge amount of power saving.

• Journal of the Korean housing association
• /
• v.17 no.5
• /
• pp.27-37
• /
• 2006

This paper analyzed statistically two corpora that were constructed from the texts about house designs written by Korean architects and PA Awards architects. The main results are as follows; (1) The numbers of words in Korean house-design corpus were 9,352 and those of words in PA Awards house design corpus were 2,379. The former were 18.7% and the latter 4.8% of about 50,000 words regarded as the rest using scale in actual life. (2) When the architects described their house designs, the lexicon-concentration phenomenon was pervasive in both groups. Therefore, we can infer that the high-frequency lexicons are very important in house design. (3) The architects' behaviour patterns of using the house-design lexicons, went by rules according to the word frequency order. The tendency formulas of them had the $R^{2}$ values which were more than 90%. (4) In Korean house design corpus, the high frequency lexicons were '공간', '층', '주택', '집', '대지', '거실', and '실'. In PA awards house design corpus, they were 'house','room','space','living','wall','level' and 'area'. From these results, We can tell that 'space' is the highest frequency word in house design of the two groups, and that '대지 ' and 'wall' are the words that reveal well the differences between the two groups.

• ETRI Journal
• /
• v.26 no.6
• /
• pp.622-634
• /
• 2004

In this paper, we discuss the design problem and the robustness of space-frequency trellis codes (SFTCs) for multiple input multiple output, orthogonal frequency division multiplexing (MIMO-OFDM) systems. We find that the channel constructed by the consecutive subcarriers of an OFDM block is a correlated fading channel with the regular correlation function of the number and time delay of the multipaths. By introducing the first-order auto-regressive model, we decompose the correlated fading channel into two independent components: a slow fading channel and a fast fading channel. Therefore, the design problem of SFTCs is converted into the joint design in both slow fading and fast fading channels. We present an improved design criterion for SFTCs. We also show that the SFTCs designed according to our criterion are robust against the multipath time delays. Simulation results are provided to confirm our theoretic analysis.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.8
• /
• pp.1388-1393
• /
• 2010

This paper presents a new methodology for designing a dielectric waveguide filter with the cutoff frequency of 2.4 GHz based on the continuum design sensitivity analysis. An analytical sensitivity formula is derived in frequency domain and then unified program architecture applicable to the optimal design of high-frequency devices is proposed. A three-dimensional dielectric resonator used in waveguide filters has been tested to illustrate the validity of the proposed method.

• Nuclear Engineering and Technology
• /
• v.38 no.6
• /
• pp.551-560
• /
• 2006

In this study, a controller for a nuclear reactor power is designed. The reactor is modeled using the three dimensional reactor design code MASTER. From the relationship of the input and output of the reactor code, a reactor dynamic model is derived by the system identification method. This model is more realistic than the one based on mathematical theories. With this model, a robust controller is designed by the extended frequency response method. As this method has the same theoretical background as the classical method, all of the existing design techniques of the classical method can be used directly. Furthermore, by introducing the real part of a Laplacian operator into the frequency response, the control design specification can be considered at the initial stage of design. The designed controller is simple, and gives a sufficient robustness with good performance.

• Journal of Sensor Science and Technology
• /
• v.5 no.4
• /
• pp.81-87
• /
• 1996

This paper presents the optimal design method of SAW filters with arbitrary frequency characteristics. The design program using the unconstrained nonlinear optimization method and FFT algorithm is developed for optimal design of SAW filters with arbitrary frequency characteristics. As a design example, a SAW TV IF filter with asymmetric-amplitude and nonlinear-phase frequency characteristics is designed.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2004.05b
• /
• pp.318-322
• /
• 2004

This study was conducted to derive the regional design rainfall by the regional frequency analysis based on the regionalization of the precipitation. For the estimation of the regional design rain(all, classification of the climatologically and geographically homogeneous regions should be preceded preferentially The optimal regionalization of the precipitation data were classified by the above mentioned conditions for all over the regions except Jeju and Ulleung islands in Korea. Relative root mean square error(RRMSE), relative bias(RBIAS) and relative reduction(RR) in RRMSE for the design rainfall were computed and compared between the regional and at-site frequency analysis. Consequently, optimal design rainfalls following the classified regions and consecutive durations were derived by the regional frequency analysis using GEV distribution which was identified to be more optimal one than the other applied distributions.

• Journal of Ocean Engineering and Technology
• /
• v.27 no.5
• /
• pp.36-42
• /
• 2013

We present the optimum design for the cross-sectional(sizing) and shape optimization of truss structures with natural frequency constraints. The optimum design method used in this paper employs continuous design variables and the Harmony Search Algorithm(HSA). HSA is a meta-heuristic search method for global optimization problems. In this paper, HSA uses the method of random number selection in an update process, along with penalty parameters, to construct the initial harmony memory in order to improve the fitness in the initial and update processes. In examples, 10-bar and 72-bar trusses are optimized for sizing, and 37-bar bridge type truss and 52-bar(like dome) for sizing and shape. Four typical truss optimization examples are employed to demonstrate the availability of HSA for finding the minimum weight optimum truss with multiple natural frequency constraints.

• Journal of the Korean Society for Precision Engineering
• /
• v.12 no.6
• /
• pp.137-144
• /
• 1995

The purpose of this study is to obtain a foundation data for chassis design and road noise reduction of automobiles. Using the combination of the automobile, radial tires and instrumentation equipment, experimental investigation was carried out to examine the characteris- tics of the structural vibration of tire as the key to obtaining the effective parameters for reducing road noise. From the results of this studies it has been confirmed that the specific ranges of natural frequency of tire exciting the suspension and chassis system. And the tire, axle and chassis natural frequency of automobile govern the road noise. Results show that material properties of tire and experimental condition are major parameter for shifting of tire natural frequency. These results would be utilized as basic materials for the design of chassis design with papametric study, which enables a designer of an automobile to foresee the influence of the various design factors or operating conditions.

• Journal of KSNVE
• /
• v.5 no.3
• /
• pp.395-402
• /
• 1995

In general low frequency vibration characteristics like an idleshake is mainly influeced by pillar section properties and joints. So the design technique development of vehicle pillar structures is required to initial design and vehicle development stage. In this paper to develop pillar structure design technique considering low frequency vibration characteristics, strain energy method, design sensitivity analysis method, and design optimization method using commercial finite element analysis program and optimization program are presented.