• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.228-231
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• 1999

This paper describes the design and implementation of an application specific instruction-set processor developed for embedded DSP applications. The instruction-set has an uniform size of 16 bits, and supports 3 types of instructions: Primitive, Complex, and Specific. To reduce code size and cycle count we introduce complex instructions that can be selected according to the application under consideration, which leads to 50% code size reduction maximally. The processor has two independent data memories to double the data throughput and the address space. The processor is synthesized by 0.6$\mu$m single-poly double-metal technology. Critical path simulation shows that the maximum frequency is 110MHz and total gate count is 132, 000.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.878-883
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• 2003

To modify some problems of ACI shear provisions, ultimate shear strength equation considering size effect and arch action to compute shear strength in high-strength concrete beams without stirrups is presented in this research. Three basic equations, namely size reduction factor, rho factor, and arch action factor, are derived from crack band model of fracture mechanics, analysis of previous some shear equations for longitudinal reinforcement ratio, and concrete strut described as linear function in deep beams. Constants of basic equations are determined using statistical analysis of previous shear testing data. To verify proposed shear equation for each variable, namely d, , ρ, f/sub c/' and aid, about 250 experimental data are used and proposed shear equation is compared with ACI 318-99 code, CEB-FIP Model code, Kim & Park's equation and Zsutty's equation. While proposed shear equation is simpler than other shear equations, it is shown to be economical predictions and reasonable safety margin. Hence proposed shear strength equation is expected to be applied to practice shear design.

• Journal of Energy Engineering
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• v.25 no.1
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• pp.69-75
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• 2016

Bubble size is a key parameter for an accurate prediction of bubble behaviours in the multi-dimensional two-phase flow. In the current STAR CCM+ CFD code, a mechanistic bubble size model $S{\gamma}$ is available for the prediction of bubble size in the flow channel. As another model, Yun model is developed based on DEBORA that is subcooled boiling data in high pressure. In this study, numerical simulation for the gas-liquid two-phase flow was conducted to validate and confirm the performance of $S{\gamma}$ model and Yun model, using the commercial CFD code STAR CCM+ ver. 10.02. For this, local bubble models was evaluated against the air-water data from DEDALE experiments (1995) and Hibiki et al. (2001) in the vertical pipe. All numerical results of $S{\gamma}$ model predicted reasonably the two-phase flow parameters and Yun model is needed to be improved for the prediction of air-water flow under low pressure condition.

• Journal of the Korean Physical Society
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• v.73 no.10
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• pp.1495-1501
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• 2018

We have developed an extended three-dimensional free-electron laser (3D FEL) code with source-dependent expansion to calculate the intensity of the radiation field and the spot size in a free-electron laser oscillator. The effect of the wiggler field errors was evaluated for the case of a planar wiggler generated by a magnet stack with parabolic shaped pole faces by using the extended three-dimensional equations in a free-electron laser oscillator based on the proposed FEL facility which is to be operated in the far-infrared and the infrared regions. The radiation spot size due to the wiggler field errors also have been analyzed for wiggler errors of ${\Delta}B/B=0.0$, 0.03, 0.06 and 0.09% at z = 1 m and z = 2 m. The effect of the diffraction of radiation field due to the wiggler field errors of ${\Delta}B/B=0.0$ and ${\Delta}B/B=0.09%$ at 200 passes was evaluated by using the extended 3D code that we developed. The variation of the curvature of the phase front and the effect of the radiation field intensity due to the wiggler field errors were also evaluated for B = 0.5 T and B = 0.7 T with the wiggler error of ${\Delta}B/B=0.09%$ at 200 passes and the results were compared to those of without errors. The intensity of the radiation, behavior of the radiation spot size and the variation of the curvature of the phase were highly sensitive to the wiggler error of ${\Delta}B/B$ > 0.09%, but were less sensitive to the wiggler errors for ${\Delta}B/B$ < 0.09% in a free-electron laser (FEL) oscillator based on the proposed FEL facility.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8C
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• pp.1069-1075
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• 2004

In this paper, we show the equivalence between complementary code keying (CCK) codeword and coset of the first order Reed-Muller (RM) code with variables of three. The CCK codewords are Golay sequences which have peak-to-average power ratio (PAPR) of two at most and can correct one error. We propose a CCK-orthogonal frequency division multiplexing (OFDM) modem to reduce PAPR. Also, we present the performance improvement techniques by increasing the variables of four to correct three errors and reduce PAPR at least 9㏈ with this system. Although, two Fast Hadamard Transform (FHT) blocks of size 8 64 are required at the receiver, we reduce the complexity by using FHT blocks of size 8 64 and 2 4 without deteriorating the performance. We generalize our results that we may increase the variables of RM code to enhance the error correcting and PAPR reduction capabilities without increasing receiver's complexity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3C
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• pp.83-91
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• 2005

We analyze the performance of an adaptive hybrid search code acquisition algorithm for direct-sequence code division multiple access (DS-CDMA) systems under slowly-moving mobile environments. The code acquisition algorithm is designed to provide the desired feature of constant false alarm rate (CFAR) to cope with nonstationarity of the interference in CDMA forward links. An analytical expression for the mean acquisition time is first derived and the probabilities of detection, miss, and false alarm are then obtained for frequency-selective Rayleigh fading environments. The fading envelope of a received signal is assumed to be constant over the duration of post-detection integration (PDI), considering slow fading environments. Finally, the performance of the designed code acquisition algorithm shall be evaluated numerically to examine the effect of some design parameters such as the sub-window size, size of the PDI, decision threshold, and so on, considering cdma2000 environments.

• The KIPS Transactions:PartD
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• v.12D no.3 s.99
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• pp.409-416
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• 2005

Even though development paradigm of software has been changing very fast at the beginning of 21st Centuries, there are just few studies of quality and estimation metrics appropriate for Web environment. So in this study after analyzing the correlation between the size of the final code and property of objects, three industrial real world projects written in ASP have been used for deriving programs with high possibilities of faults. And then the size of programs was analyzed to correlate with the number of classes or the number of methods through linear regression. Among the web software with the complex architecture or server, client and un, type or form file written in Javascript for client has the high correlation and the number of methods is well correlated with the size of final code.

• Fashion & Textile Research Journal
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• v.16 no.5
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• pp.766-775
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• 2014

This study is aimed to research the actual wearing condition of ballet dancewear of girls aged between 2 and 6 years on its design, size and fit. Survey data were collected from 171 mothers who have a girl learning ballet dance. The questionnaire was composed with ballet education, ballet dancewear purchasing, preference on design, size selection, and fitting. The collected data were analyzed with frequencies statistics, ${\chi}^2$-test, ANOVA using the SPSS WIN 20.0. The results are as follows; High rate of respondents said that the purpose of ballet education was for good body balance, leisure activity, and height growth. The main method of purchase was online shopping. The design, price, size and fit were identified as important ballet dancewear attributes for girls. The most preferred style of ballet dancewear were 'short sleeve skirted leotard' and 'camisole skirted leotard' which look like dress. The respondents reported slight satisfaction with size and fit, price, convenience in action, sewing and durability. The most preferred sizing system was code by height but any ballet dancewear makers don't use code by height. Therefore it is difficult for consumers to select size. Retailers and manufacturers could potentially use the results of this study to improve the sizing system and fit for children's ballet dancewear.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.41-46
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• 2000

In this paper, we analyze the performance of W-CDMA systems using turbo code in the wideband multipath channel. The strength of each multipath component is assumed to be Rayleigh distributed. Turbo codes of long block sizes have been known to show very good performance in a AWGN channel. Recently, turbo codes of short block sizes suitable for real time communication systems have attracted a lot of attention. Thus, in this paper we consider the turbo code of 1/3 code rate and short frame size of 192 bits in wideband mobile multipath channel. We analyze the performance of W-CDMA systems with 10MHz bandwidths in the case of employing RAKE receiver with not only MRC diversity but also turbo code.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.2
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• pp.417-422
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• 2010

When memory devices are exposed to space environments, they suffer various effects such as SEU(Single Event Upset). Memory systems for space applications are generally equipped with error detection and correction(EDAC) logics against SEUs. In this paper, several error detection and correction codes - RS(10,8) code, (7,4) Hamming code and (16,8) code - are analyzed and compared with each other. Each code is implemented using VHDL and its performances(encoding/decoding speed, required memory size) are compared. Also the failure probability equation of each EDAC code is derived, and the probability value is analyzed for various occurrence rates of SEUs which the STSAT-3 possibly suffers. Finally, the EDAC algorithm for STSAT-3 is determined based on the comparison results.