• 제목/요약/키워드: multi-dimensional

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이차원 다중젯트의 유동 및 열전달 특성의 수치적 해석(II) -돌출열원이 있는 경우의 유동 및 열전달 특성- (A Numerical Analysis of Flow and Beat Transfer Characteristics of a Two-Dimensional Multi-Impingement Jet(II))

  • 장대철;이기명
    • Journal of Biosystems Engineering
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    • 제20권1호
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    • pp.66-72
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    • 1995
  • A numerical study for a two dimensional multi-impingement jet with crossflow of the spent fluid has been carried out. To study the flow characteristics especially in the jet flow region, three different distributions of mass flow rate at 5-jet exits were assumed. For each distribution, various Reynolds numbers ranging from laminar to turbulent flows were considered. Calculations drew the following items as conclusion. 1) A periodical fully developed flow was observed from the third protrusion. This was also observed from previous experimentally by Whidden at al. The Nessult number at the protrusion surface increased mildly as going downstream. 2) The low Reynolds number turbulence model of Launder and Sharma was found to be adequate for the prediction of fluid flow and heat transfer characteristics of two dimensional multi-jet configuration. 3) The Nusselt number at the protrusion surface was nearly proportional to the square root of the Reynolds number.

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Multi-Dimensional Selection Method of Port Logistics Location Based on Entropy Weight Method

  • Ruiwei Guo
    • Journal of Information Processing Systems
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    • 제19권4호
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    • pp.407-416
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    • 2023
  • In order to effectively relieve the traffic pressure of the city, ensure the smooth flow of freight and promote the development of the logistics industry, the selection of appropriate port logistics location is the basis of giving full play to the port logistics function. In order to better realize the selection of port logistics, this paper adopts the entropy weight method to set up a multi-dimensional evaluation index, and constructs the evaluation model of port logistics location. Then through the actual case, from the environmental dimension and economic competition dimension to make choices and analysis. The results show that port d has the largest logistics competitiveness and the highest relative proximity among the three indicators of hinterland city economic activity, hinterland economic structure, and port operation capacity of different port logistics locations, which has absolute advantages. It is hoped that the research results can provide a reference for the multi-dimensional selection of port logistics site selections.

A state-space realization form of multi-input multi-output two-dimensional systems

  • Kawakami, Atsushi
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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    • pp.214-218
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    • 1992
  • In this paper, we propose a method for obtaining state-space realization form of two-dimensional transfer function matrices (2DTFM). It contains free parameters. And, we perform various consideration about it. Moreover, we present the conditions so that the state-space realization form exists.

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정상 중력장에서 낮은 스트레인율을 갖는 대향류 비예혼합화염의 소화한계 (Extinction Limits of Low Strain Rate Counterflow Nonpremixed Flames in Normal Gravity)

  • 오창보;최병일;김정수;;박정
    • 대한기계학회논문집B
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    • 제29권9호
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    • pp.997-1005
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    • 2005
  • The extinction characteristics of low strain rate normal gravity (1-g) nonpremixed methane-air flames were studied numerically and experimentally. A time-dependent axisymmetric two-dimensional (2D) model considering buoyancy effects and radiative heat transfer was developed to capture the structure and extinction limits of 1-g flames. One-dimensional (1D) computations were also conducted to provide information on 0-g flames. A 3-step global reaction mechanism was used in both the 1D and 2D computations to predict the measured extinction limit and flame temperature. A specific maximum heat release rate was introduced to quantify the local flame strength and to elucidate the extinction mechanism. Overall fractional contribution by each term in the energy equation to the heat release was evaluated to investigate the multi-dimensional structure and radiative extinction of 1-g flames. Images of flames were taken for comparison with the model calculation undergoing extinction. The two-dimensional numerical model was validated by comparing flame temperature profiles and extinction limits with experiments and ID computation results. The 2D computations yielded insight into the extinction mode and flame structure of 1-g flames. Two combustion regimes depending on the extinction mode were identified. Lateral heat loss effects and multi-dimensional flame structure were also found. At low strain rates of 1-g flame ('Regime A'), the flame is extinguished from the weak outer flame edge, which is attributed to multi-dimensional flame structure and flow field. At high strain rates, ('Regime B'), the flame extinction initiates near the flame centerline due to an increased diluent concentration in reaction zone, which is the same as the extinction mode of 1D flame. These two extinction modes could be clearly explained with the specific maximum heat release rate.

Evaluation and Optimal Arrangement of Multi-Dimensional Consecutive System

  • 안해일
    • 한국신뢰성학회:학술대회논문집
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    • 한국신뢰성학회 2000년도 추계학술대회
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    • pp.397-397
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    • 2000
  • There exists an increasing need of study for generalized consecutive k-out-of-n systems. This paper demonstrates that a recursive formula for multi-dimensional consecutive k-out-of-n systems can be systematically developed by means of conventional structure function analysis. By taking advantage of notational convenience, the formulae expressed in the same recursive fashion just as the one dimensional consecutive k-out-of-n system. With the aids of the recursive formulae, not only the exact reliability of the system, but also the optimal arrangement of components is obtainable in a straightforward way.

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소비자의 다차원가격 평가노력에 대한 제품관여도와 브랜드선호도의 영향 (Effect of Product Involvement and Brand Preference on Consumers' Evaluation Effort for Multi-Dimensional Prices)

  • 김재영
    • 유통과학연구
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    • 제13권4호
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    • pp.55-64
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    • 2015
  • Purpose - Multi-dimensional prices comprise multiple components such as monthly payments and a number of payments rather than a single lump-sum amount. According to previous studies, an increase in the number of price dimensions leads to a massive amount of cognitive stress resulting in incorrect calculation, and deterioration in the consistency of the price judgment. However, an increase only in the level of complexity of calculating multi-dimensional prices does not always result in a corresponding decrease in the accuracy of price evaluation. Since diverse variables could affect consumers' purchase-decision-making process, the results of price evaluation would be different. In this study, an empirical analysis was performed to determine how the accuracy of price evaluation varies depending on the extent of the complexity of price dimensions using product involvement and brand preference as moderating variables. Research design, data, and methodology - A survey was conducted on 260 students, and 252 effective responses were used for analysis. The data was analyzed using t-test, one-way ANOVA, and two-way ANOVA. In this study, six hypotheses were developed to examine the effect of product involvement and brand preference on consumers' evaluation effort of multi-dimensional prices. Results - As the number of price dimensions increased, accuracy of price evaluation appeared to be low in high involvement, as expected. However, it showed no differences in price evaluation effort when the level of complexity of calculating multi-dimensional prices is low. When a small number of price dimensions are presented in both cases of high and low involvement, accuracy of price evaluation is much higher in a weak brand preference. On the contrary, a strong brand preference enhances an accuracy of price evaluation only in case of low involvement when the number of price dimensions is increased. An interaction effect of product involvement and brand preference on consumers' evaluation of multi-dimensional prices did not exist irrespective of the level of complexity of calculating prices being high or low. Conclusions - When the number of price dimensions is small, consumers' effort for price evaluation shows almost no difference without the moderating effect of involvement, and a weak brand preference leads to a higher accuracy of price evaluation in an effort to make the best selection. No interaction effect of product involvement and brand preference was found except for a main effect of brand preference. When a price is composed of multiple dimensions rendering it more difficult to calculate the final price, the effort for price evaluation was expected to decrease only slightly in case of combination of high involvement and strong brand preference. This is because people have a higher purchase intentions and trust for that particular brand. However, the accuracy of price evaluation was much lower in cases of high involvement, and there was no interaction effect between product involvement and brand preference except for a main effect of involvement and brand preference, respectively.