• Title/Summary/Keyword: frequency problem

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A Study about Fitting of Children's Ready-to-Wear Clothing (학령기 아동의 기성복 치수 적합성에 관한 연구)

  • Yi, Gyoung-Nam;Hahm, Ock-Sang
    • Fashion & Textile Research Journal
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    • v.2 no.2
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    • pp.138-145
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    • 2000
  • The problem of fitting of children's clothing was researched through survey papers. The survey subjects were the mothers of elementary school students (grade 1 6) and the appropriateness of size, satisfaction with size, and fittings were asked. The survey area was divided into urban and rural areas. The following is the result: The children's clothing was mostly purchased in stores that carry lower-middle price range. The elements considered upon purchase were in the order of price, size, color and patterns. The frequency of purchase is 2 outfits a year, and the highest rate purchase was shown during the change of seasons. The size was picked through trying on the garment. The preferred indication of size was the one marked according to body size. The most popular size upon purchase was one size bigger than the proper fitting size. Mothers want their children to be able to wear one outfit for two years and actually children were able to wear them for two years. The highest degree of satisfaction upon proper fitting was bust girth and shoulder breath. The most frequent reason for a new purchase is the length. The most frequent dissatisfaction is the way buttons are sowed on.

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Study on Appearance-oriented, Appearance Management Behavior according to the types of Masculinity (남성성유형에 따른 외모지향도, 외모관리행동 연구)

  • Lee, Hyun-Ok;Ku, Yang-Suk
    • Fashion & Textile Research Journal
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    • v.15 no.6
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    • pp.923-931
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    • 2013
  • The purpose of this study was to examine the effect of the type of masculinity on appearance-oriented and appearance management behavior. Questionnaires were administered to 201 males 20s to 50s living in Daegu. The SPSS 20.0 package was utilized for data analysis which included frequency analysis, Cronbach's ${\alpha}$, factor analysis, cluster analysis, regression analysis, t-test and logistic regression. First, factor analysis in a appearance management behavior and the type of masculinity, were cluster analysis in appearance-oriented. Were used to analyze the problem of the study by classified five factors and two groups. The results of this study were as follows: First, the masculinity of Retro sexual, Metro sexual, Techno sexual showed a negative influence on appearance-oriented. Second, the masculinity had a influence on appearance management behavior. M-ness showed a negative influence on skin care, Metro sexual showed a positive influence on skin care, hair/fashion, cosmetics, plastic surgery. And Retro sexual showed a influence on skin care, positive influence on hair/fashion, cosmetics. Techno sexual showed a positive influence on body management, skin care, hair/fashion. Uber sexual showed a positive influence on body management, cosmetics of appearance management. Third, the appearance-oriented had a differences on body management, hair/fashion, cosmetics, plastic surgery of appearance management behavior.

A Case Study of Spatial Composition of Elderly Skilled Nursing Facility - Focused on 5 facilities of Jeonbuk Province of Korea - (노인 전문요양시설의 공간구성에 관한 연구 - 전라북도 소재 5개 시설을 중심으로 -)

  • 이민아;유옥순
    • Korean Institute of Interior Design Journal
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    • v.13 no.1
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    • pp.62-69
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    • 2004
  • The purpose of this study was to analyze spatial composition of elderly skilled nursing facility and to provide basic information for setting up the detail facility architectural guidelines. The results of the study were following: the residential spaces of the facilities in this study were more or less overcrowded since their capacity were more than 5 elderly residents. The dimensions of some residential spaces did not even come up to the standard of elderly welfare law in force. On the other hand, the facilities had a tendency to use a space with multiple purposes or to allocate a space but to leave it with no use. Moreover comparing with the 1st floor, which was mainly for the staffs and had enough space to spare, the upper floor which was for the elderly residents, was crowded with nursing staffs and elderly residents and had densely closed residential and public spaces. For the problem solving, law and regulation modification is needed according to the case study about the usage and using frequency of each facility space. And the crowded area for the elderly residents could be enlarged through the reduction(or combination) of the rarely used spaces and moving a few residential spaces into the 1st floor.

Dynamic Analysis of the Tire by Sector Method (섹터해석법을 이용한 타이어의 동특성 해석)

  • 이인원;김동옥;김항우;정상우
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.9
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    • pp.2173-2180
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    • 1995
  • This paper presents free vibration analysis method using the characteristics of the rotationally periodic structures and includes the analysis results of a tire as an example. The normal modes of the rotationally periodic structures are the kind of standing waves, so all sectors have the same deflection shapes, and only different phases. This property makes it possible to derive the analysis method called sector method. The sector method can give the accurate natural frequencies and the corresponding mode shapes of the rotationally periodic structure with information of only one sector. When the free vibration analysis is performed to find the dynamic characteristics of the rotationally periodic structure by using the sector method, the computer memory spaces and the CPU times can be saved. We obtained much economic benefits by using the sector method in the analysis of dynamic characteristics of a tire made of non-linear materials.

The Characteristics of Line Heating Using Hydrox Gas (수산소 혼합가스를 이용한 선상가열 특성)

  • Kim, Hong-Gun;Kwac, Lee-Ku
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.20 no.4
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    • pp.407-411
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    • 2011
  • The technology of line heating has evolved in various methods. Among them, fossil fuels like ethylene gas and LPG(Liquid Petroleum Gas) are widely used due to their simple utility. In the meantime, the technology implementing high frequency for line heating has also been developed continually, but its manufacturing technology or application includes lots of problems by now. One of the main characteristics of line heating using conventional technolob'Y is the quenching effect followed by heating process. On the other hand, hydrox gas which is mixed by hydrogen and oxygen is a prominent candidate for an application without above shortcomings. Especially, it is found that line heating using hydrox gas is tremendously effective taking low cost as well as low noise. In this paper, a small cell with high efficiency which can minimize installing space is developed to deal with the problem installing in narrow place. Experiments to prove the validation, efficiency and effectiveness is carried out by characterizing in the line heating of steel. It is found that the energy saving of using hydrox gas for line heating is significant and that the deviation performance is reduced by 78~89%. Furthermore, the noise is also reduced as amount of 18.3% though the heating time is not too different.

The Stability Conditions, Performance and Design Methodology for the Positive Position Feedback Controller (양변위 되먹임 제어기의 안정성, 제어 성능 및 설계 방법)

  • Kwak, Moon-Kyu;Han, Sang-Bo;Heo, Seok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.3
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    • pp.208-213
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    • 2004
  • This paper is concerned with the theoretical estimation of the single-input single-output(SISO) positive position feedback(PPF) controller and the derivation of the stability conditions for the multi-input multi-output (MIMO) PPF controller. Although the stability condition for the SISO PPF controller was derived in the earlier works, the question regarding the performance estimation of the SISO PPF controller has never been studied theoretically. Hence, the SISO PPF controller for the single degree-of-freedom system was first investigated and then control parameters including gain, the filter frequency, and the damping factor of the PPF controller were analyzed in detail thus providing the design methodology for the SISO PPF controller. In the case of real structure. there are infinite number of natural modes so that some modes are to be controlled by a limited number of actuator and sensor. Based on the theoretical results on the SISO PPF controller, the stability condition for the multi-input multi-output PPF controller was derived when only the few number of modes are to be controlled. The control spillover problem is also discussed in detail.

Hydroelastic Vibration of a Rectangular Tank Partially Surrounding with a Liquid (유체에 부분적으로 둘러싸인 사각형 용기의 접수진동)

  • Jeong, Kyeong-Hoon;Kim, Jong-Wook
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.25 no.3
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    • pp.207-215
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    • 2015
  • This paper deals with a theoretical method to calculate natural frequencies of a fixed-free rectangular tank partially in contact with an outer water gap. Orthogonal polynomials satisfying the boundary conditions of the tank are used as admissible functions in the Rayleigh-Ritz method. A quarter model of the liquid-coupled system is constructed and it is simplified to a line supported flat plate in contact with the liquid. The liquid displacement potential functions satisfying the Laplace equation and water boundary conditions are derived, and the finite Fourier transform is accomplished in conjunction with the compatibility requirement along the contacting interfaces between the tank and water. An eigenvalue problem is derived so that the natural frequencies of the wet rectangular tank can be extracted. The predictions from the proposed analytical method show good agreement with the finite element analysis results.

A Framework for Investment Justification and Economic Operation- (한국의 다목적댐 수력발전 체계-투자의 정당화와 경제적 운영-)

  • 이승규;박용삼
    • Journal of the Korean Operations Research and Management Science Society
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    • v.12 no.1
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    • pp.157-157
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    • 1987
  • Hydro-electric power generation from multi-purpose dams has been playing important roles in the electric power supply network in Korea. Although the total share of hydro power in national electricity supply now becomes very small, the peak-shaving and frequency control capability of hydro power helps the power company enormously in maintaining the quality of power. But since the company that builds and operates the multi-purpose dams in Korea has to sell all the electricity produced to the monopolistic utility, there have been various problems in justifying the investment, designing pricing mechanism, and controlling operations of the power plants. In addition, economic evaluation of the hydro power has been distorted by a variety of reasons and hence it has been very difficult to encourage effective development and utilization of national water resources. To make the problem worse, both parties are public companies with X-inefficiency problems. Thus, changing environment requires to reengineer the system that governs hydro power generation. We address the problems of Korean hydro-electric power generation system in four areas: the investment justification process, the operations decison right of the hydro power plants, the pricing of the purchased-power, and the negotiation of contract revision. Then we propose improvement directions of new hydro-electric power system in view of static and dynamic efficiency, X-inefficiency and equity.

NO Reduction and High Efficiency Combustion by Externally Oscillated Staging Burner

  • Lim, Mun-Sup;Yang, Won;Chun, Young-Nam
    • Environmental Engineering Research
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    • v.14 no.3
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    • pp.158-163
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    • 2009
  • It is difficult for a burner to achieve an increase in combustibility and a reduction of NOx emission, simultaneously. The reason is because thermal NOx could be reduced at low temperature, while the combustibility should be decreased. To solve this problem, an externally oscillated staging burner was developed, and experiment was conducted according to effective parameters. The combustibility could be improved through the accelerated transfer of heat, mass and momentum obtained by external oscillation. Also, NO is reduced by the decrease of residence time of burning gas in the local highest-temperature spot, which is decreased by the external oscillation and fuel staging. Experiments on variables were conducted to determine the reference flame, and the flame generating the lowest NO concentration was selected. The conditions of reference flame were oscillation frequency 250 Hz, sound pressure 1 VPP, and air ratio 1.1, and NO and CO concentrations were 1ppm and 20 ppm, respectively.

A Study for the Improvement of the Fault Decision Capability of FRTU using Discrete Wavelet Transform and Neural Network (이산 웨이블릿 변환과 신경회로망을 이용한 FRTU의 고장판단 능력 개선에 관한 연구)

  • Hong, Dae-Seung;Ko, Yoon-Seok;Kang, Tae-Ku;Park, Hak-Yeol;Yim, Hwa-Young
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.7
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    • pp.1183-1190
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    • 2007
  • This paper proposes the improved fault decision algorithm using DWT(Discrete Wavelet Transform) and ANNs for the FRTU(Feeder Remote Terminal Unit) on the feeder in the power distribution system. Generally, the FRTU has the fault decision scheme detecting the phase fault, the ground fault. Especially FRTU has the function for 2000ms. This function doesn't operate FI(Fault Indicator) for the Inrush current generated in switching time. But it has a defect making it impossible for the FI to be operated from the real fault current in inrush restraint time. In such a case, we can not find the fault zone from FI information. Accordingly, the improved fault recognition algorithm is needed to solve this problem. The DWT analysis gives the frequency and time-scale information. The neural network system as a fault recognition was trained to distinguish the inrush current from the fault status by a gradient descent method. In this paper, fault recognition algorithm is improved by using voltage monitoring system, DWT and neural network. All of the data were measured in actual 22.9kV power distribution system.