• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.1
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• pp.22-32
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• 2007

This paper describes a study of a helicopter database for the sizing stage of a preliminary design process. The database includes specifications and performance parameters for more than 150 conventional single rotor helicopters currently in market. Design parameters, including configuration and weight parameters, have been analyzed and trend curve equations(regression equations) are derived using the regression analysis method. Finally, the applicability of this research result was verified whether the method is reliable for being adopted as a useful design tool in the early stage of a helicopter design process.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.2
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• pp.26-35
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• 2006

Design parameters of manned and unmanned rotorcrafts have been investigated to construct a design database and to derive trend curves. Design parameters of 78 manned rotorcrafts and 33 unmanned rotorcrafts have been collected and analyzed using linear regression method. Six kinds of trend curves equations are derived. Most of trend curves derived are relatively meaningful according to the calculated correlation and determination coefficients. The comparisons between manned and unmanned rotorcraft characteristics are performed. It has been drawn according to the comparisons that unmanned rotorcraft has smaller main rotor diameter and maximum take-off weight, bigger tail rotor size and similar level of empty weight fraction than manned rotorcraft.

• Journal of the Korean Society of Costume
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• v.50 no.2
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• pp.167-182
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• 2000

The purpose of this study is to examine the art nouveau fashion represented in the end of the twentieth century. The characteristics of art nouveau are naturalism, medievalism , exoticism, and decadentism. The influences of art nouveau were seen in the fashion of the late nineteenth century : S-curve silhouette and organic curve motives printed on hems. Art nouveau has reappeared in modern fashion trends such as romanticism , decadence, ecology, ethno, and fusion. To sum up, art nouveau fashion at the end of the twentieth century is classified into four shapes. First, art nouveau appears in naturalism. Influenced by the arts and crafts movements and naturalistic trend, it has reappeared at the end of the twentieth century in themes like 'art & craft'. This expression technique is to objectively nature and to represented art nouveau textiles. Second, S-curve silhouette appeared at the end of nineteenth century's fashion with the art nouveau influenced rejection of the bustle style. At the end of the twentieth century, the design , emphasizing the hip, is represented in fashion collections as a phenomenon of romanticism . Especially the art nouveau silhouette of the end of the twentieth century does not represent S-curve silhouette. But , it emphasizes the hip only. Third, Art nouveau exoticism by symbolism is influenced by Chinese and Celtic art, the Middle Ages, and the exoticism that appeared in fashion at the end of the nineteenth century : harem style, kimono style, and turbans. Exoticism at the end of the twentieth century is expressed by optical flower prints and successive floral print arrangements as seen in the themes of ethno and fusion. Fourth, one of the characteristics of art nouveau, decadence is influenced by the pre-raphaelite brotherhood. This is expressed in the images of vampires, and symbolism expressing grotesque insect motives and decadent successive curves. At the end of the twentieth century decadence is represented in fashion ; grotesque insect motives, tatto looks of organic curve motives celtic hair style, see-through fashion, grotesque make-up . Besides hair style techniques, decadent expressions applying art nouveau paintings also appeared. Finally , art nouveau fashion represented as a fashion trend at the turning point to the new millennium is one of great significance as an organic, an environment-intimate and continuance-possible design in a future.

• Electrical & Electronic Materials
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• v.7 no.2
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• pp.107-116
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• 1994

In the manufacturing of VLSI circuits, variations of device characteristics due to the slight differences in process parameters drastically aggravate the performances of fabricated devices. Therefore, it is very important to establish optimal process conditions in order to minimize deviations of device characteristics. In this paper, we used one-dimensional process simulator, SUPREM-II, and two dimensional device simulator, MINIMOS 4.0 in order to extract optimal process parameter which can minimize changes of the device characteristics caused by process parameter variation in the case of short channel nMOSFET and pMOSFET device. From this simulation, we have derived the dependence relations between process parameters and device characteristics. Here, we have suggested a method to extract process parameters from design trend curve(DTC) obtained by these dependence relations. And we have discussed short channel effects and device limitations by scaling down MOSFET dimensions.

• Journal of the Korea Furniture Society
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• v.16 no.2 s.30
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• pp.49-57
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• 2005

This study purposed to grasp the Design Characteristic of the representative Furnitures produced recently by Domestic Furniture Manufacturers. As for the researching method, setting as the object of the selected 7 furniture manufacturers, through the regional classification such as living room, bedroom, dining room, and then chose again the 395 items of furnitures to be analyzed. The Design Characteristic of the chosen furnitures has been examined clearly by the analysis standard framework for those peculiarities at view of aesthetic, decorating and material. As the result of analysis, as for the aesthetic Peculiarity of the furnitures, the rectilinear form was overwhelming than the curve lined shape, and it was appeared that the brighter tone of color was used quite more. In the respect of aesthetic characteristic, the furnitures decorated with modern style is pretty gaining predominance than that of reflected style of traditional character, and since modern residential space has been maintained continuously as minimal shaped trend for several years, it could be known that such moulding and decorating peculiarities and also furniture as the composing factor of space had been selected together with it. Based on such conclusion, standing on this time point where the design trend of residential space is being changed, it is also considered that the Development of Furniture Design which copes positively with such change tendency in the future.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2B
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• pp.131-139
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• 2009

Recently frequent occurrences of heavy rainfall and increases of rainfall intensity resulted in severe flood damage in Korea. In order to mitigate the vulnerability of flood, it is necessary to estimate proper design rainfalls considering the increasing trend of extreme rainfalls for hydrologic planning and design. This study focused the estimation of design rainfalls in a design target year. Tests of trend indicated that there are 7 sites showing increasing trends among 56 sites which have hourly data more than 30 years in Korea. This study analyzed the relationship between mean of annual maximum rainfalls and parameters of the Gumbel distribution. Based on the relationship, this study estimated the probability density function and design rainfalls in a design target year, and then constructed the rainfall-frequency curve. The proposed method estimated the design rainfalls 6-20% higher than those from the stationary rainfall frequency analysis.

• Magazine of the Korean Society of Agricultural Engineers
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• v.30 no.4
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• pp.62-70
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• 1988

This study was conducted to solve the problems for the unsuitable parameters and the uncertainty of design flood can be appeared by low outliers were inclined to the lower part from the trend of the balance of the data. Derivation of reasonable design flood was attempted finally by modification of low outliers with analysis of flood frequency by means of Log Pearson Type Ill distribution. Three subwatersheds were selected as studying basins with the annual maximum series including low outliers along Geum River basin. The results through this study were analyzed and summarized as follows. 1. Log Pearson Type In distribution was confirmed as a reasonable one by X$^2$ goodness of fit test at Gong Ju, Gyu Am, og Cheon watershed along Geum River basin. 2. Probable flood flows for each watershed were derivated by flood frequency curve with outliers. 3. Weighted skew coefficient for each watershed was calculated for the evaluation of freq- uency factor which is needed for the modification of low outlier. 4. It was confirrned that adjusted frequency curve has a lower tendency than that of deletion of low outlier in common at all watersheds. 5. Final probable flood flows were derivated by modification with evaluation of modified basic statistics for three watersheds. 6. In comparison with a frequency curve with modification and one with outlier, The former has a higher probable flood flow within three years of return periods than that of the latter, and vice versa over three years of return periods.

• Electrical & Electronic Materials
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• v.9 no.8
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• pp.799-805
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• 1996

In short channel MOSFET, it is very important to establish optimal process conditions because of variation of device characteristics due to the process parameters. In this paper, we used process simulator and device characteristics caused by process parameter variation. From this simulation, it has been ' derived to the dependence relations between process parameters and device characteristics. The experimental result of fabricated short channel device according to the optimal process parameters demonstrate good device characteristics.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.349-356
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• 2002

There has been an increasing trend toward the use of pushover analysis as a tool for evaluating the seismic resistant and safety of a building structure in the performance based earthquake engineering field. The ATC-40 document proposed a nonlinear static procedure based on the Capacity Spectrum Method to determine earthquake-induced demand given the structure pushover curve, which a curve representing base shear versus roof displacement. However, the procedure is conceptually simple, iterative and time consuming method and may sometimes lead to no solution or multiple solutions. A new improved method of seismic performance evaluation for moment frame building, which take into account the previously mentioned deficiencies of currently used elastic design procedures, is presented in this paper. The results of nonlinear static and nonlinear time history analysis of an example high-rise steel moment frame designed by the proposed method are presented and discussed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.12
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• pp.3010-3017
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• 2000

For integrity evaluation of cracked or damaged structures, fracture toughness test results in ASTM are widely used. The fracture toughness values of the structures are used as an effective design criterion in nuclear plants and aircraft structures. Sometimes the difference of P-$\delta$ curve trend during the unloading /reloading cycle in the fracture toughness test using partial unloading compliance was observed. The phenomenon as a possible source of error in determining fracture toughness may be caused by the residual stress during unloading work-hardening and bucking of a specimen. Therefore, we evaluate the effect of bucking and compressive residual stress during the K-R and J-R testing using a finite element method.