• Title/Summary/Keyword: non-uniform

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Generation and Suppression of Non-uniform Flow in Scramjet Engines

  • Ben, Hidenori;Watanabe, Toshinori
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2004.03a
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    • pp.69-74
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    • 2004
  • In scramjet engines with sidewall compression inlet, it is well known that a non-uniform flow appears since a separated region is generated near the flow centerline on the body side. The separated region is caused by shock-boundary layer interaction and likely to cause un-start phenomena since the flow in the separated region is subsonic and acts as a communication path between the isolator and the combustor. In the present study, the non-uniform flow characteristics in the scramjet inlet-isolator region are numerically studied in detail. Effect of flow suction from body sidewall surface on the non-uniform flow field numerically examined to clarify the flow mechanism to suppress the un-start transition.

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A Comparative Study on the Clothing Behavior by a Type of Campus Wear -With an Emphasis for the Boy's and Girl's High School Students in Kwangju- (통학복 유형에 따른 의복행동에 관한 비교연구 -광주지역 남.여 고등학생을 중심으로-)

  • 유명의
    • Journal of the Korean Home Economics Association
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    • v.30 no.1
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    • pp.11-24
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    • 1992
  • The purpose of this study is to investigate the present states and preferences for a type of campus wear, the differences between the life-style variables and clothing behavior among school uniform students and non-uniform students, to explore variabels of the purchasing tendency in clothes of boys' and girls' high school students. The questionnaires were administered to samples of four boys' and girls' high schools respectively in Kwangju. The data from 522 respondants were analyzed in using Frequency and T-test. The results were as follows: 1. Most of schools are likely to take a school uniform system in the near future but students do not have favorable attitude against the system. 2. There were partly significant differences between the clothing behavior variables (boys : psychological dependence, comfort and atmosphere of the store, girls : downtown shopping) among school uniform students and non-uniform students. 3. There were partly significant differences between life-style variables(boys : leadership and social attitude, advertisement confidence, girls : price consciousness) among school uniform students and non-uniform students. 4. About 80% of the subject group planned their clothing purchase in advance, and their parents and friends influenced on clothing buying behaviors more then other fashion information sources, however, for the boy students the atmosphere of the store is most affecting variables. The store in which the subject group purchased clothing most frequently was a specialty fashion store. In clothing selection, aesthetic factors were showen as important factor and the most affecting mass media is TV.

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A Study on the Wearing Conditions of Summer School Uniform and Comfortable Uniform for Middle School Students - Focusing on Iksan city - (중학생의 여름철 교복 및 생활복 착용 실태에 관한 연구 - 익산지역을 중심으로 -)

  • Kim, Yun Hee;Lee, Jin Hee
    • Korean Journal of Human Ecology
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    • v.23 no.5
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    • pp.919-928
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    • 2014
  • The purpose of this study was conducted to improve middle school students' satisfaction on their uniform to provide basic information for the wearing condition. on their comfortable uniform. Survey was conducted on 532 boys' and girls' middle school students in Iksan City. This study analyzed the purchasing factors and modification, fitting evaluation, and satisfaction of comfortable uniform aspect of students. It was the questionnaire consisted of 18 questions in total. The results are as follows : First, boys' middle school students preferred 'activity' among the purchasing factors. Girls' middle school students preferred 'design' and 'activity' among the purchasing factors. Second, in purchasing types, boys' students bought the type of cooperative purchasing and the type of the school uniform special shop in girls' students. Third, 51.0% of the students interviewed have experienced to modify their uniforms. Since the non fashionable design and non suitable uniform length caused the students to modify their uniform. Also students did not satisfy the color and design in their comfortable uniforms. Thus school uniform maker should make that consider movement, color, design, functional elements and changing students' aesthetic sense.

An Experimental Study of Critical Heat Flux in Non-uniformly Heated Vertical Annulus under Low Flow Conditions

  • Chun, Se-Young;Moon, Sang-Ki;Baek, Won-Pil;Chung, Moon-Ki;Masanori Aritomi
    • Journal of Mechanical Science and Technology
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    • v.17 no.8
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    • pp.1171-1184
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    • 2003
  • An experimental study on critical heat flux (CHF) has been performed in an internally heated vertical annulus with non-uniform heating. The CHF data for the chopped cosine heat flux have been compared with those for uniform heat flux obtained from the previous study of the authors, in order to investigate the effect of axial heat flux distribution on CHF. The local CHF with the parameters such as mass flux and critical quality shows an irregular behavior. However, the total critical power with mass flux and the average CHF with critical quality are represented by a unique curve without the irregularity. The effect of the heat flux distribution on CHF is large at low pressure conditions but becomes rapidly smaller as the pressure increases. The relationship between the critical quality and the boiling length is represented by a single curve, independent of the axial heat flux distribution. For non-uniform axial heat flux distribution, the prediction results from Doerffer et al.'s and Bowling's CHF correlations have considerably large errors, compared to the prediction for uniform heat flux distribution.

Breakdown Characteristics of Ar/$N_2$ and Kr/$N_2$ Gas Mixtures with Pressure Variation (압력변화에 따른 Ar/$N_2$및 Kr/$N_2$ 혼합가스의 절연파괴 특성)

  • 이상우;이동인;이광식;김인식;김이국;배영호
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2001.11a
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    • pp.187-191
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    • 2001
  • In this paper, the ac breakdown characteristics of Ar/$N_2$and Kr/$N_2$gas mixtures with gas pressure range of 58.8~137.3[kPa] under uniform and non-uniform fields were investigated. Summarizing the experimental results, the breakdown voltages of Ar/$N_2$ gas mixtures were decreased with decreasing the mixture ratio of pure $N_2$gas. In case of Ar(85%)/$N_2$(15%) and Ar(70%)/$N_2$(30%) gas mixtures comparing to the pure Ar gas, the breakdown voltages under uniform field were increased about 1.8 and 2.2 times, and under non-uniform field were increased about 1.1 and 1.3 times at the pressure of 101.3[kPa]. Also, in case of Kr(85%)/$N_2$(15%) and Kr(70%)/$N_2$(30%) gas mixtures comparing to the pure Kr gas, the breakdown voltages under uniform field were increased about 1.7 and 2.0 times, and under non-uniform field were increased about 1.0 and 1.2 times.

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Interprocedural Transformations for Parallel Computing

  • Park, Doo-Soon;Choi, Min-Hyung
    • Journal of Korea Multimedia Society
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    • v.9 no.12
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    • pp.1700-1708
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    • 2006
  • Since the most program execution time is consumed in a loop structure, extracting parallelism from loop programs is critical for the taster program execution. In this paper, we proposed data dependency removal method for a single loop. The data dependency removal method can be applied to uniform and non-uniform data dependency distance in the single loop. Procedure calls parallelisms with only a single loop structure or procedure call most of other methods are concerned with the uniform code within the uniform data dependency distance. We also propose an algorithm, which can be applied to uniform, non-uniform, and complex data dependency distance among the multiple procedures. We compared our method with conventional methods using CRAY-T3E for the performance evaluation. The results show that the proposed algorithm is effective.

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The Effect of BIM in the Construction of Non-uniform Structure (비정형 구조물 시공에서의 BIM 효용성)

  • Chung, Kwang-Ryang
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.05a
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    • pp.194-195
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    • 2014
  • In modern building, it is constructed with non-uniform complex design. These buildings can't be expressed in 2-D drawings, and it requires shown in 3-D. So, BIM is necessary to communicate between a designer and constructor, and it prevents misunderstanding of drawings. Especially, to design and construct these non-uniformed buildings, BIM needs knowledge and know-how of structure engineer. BIM should fully include construction process information which satisfy constructors so it leads to success in construction market. In this Thesis, I show some example of BIM efficiency to construct non-uniformed large scale building.

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Exploiting Static Non-Uniform Cache Architectures for Hard Real-Time Computing

  • Ding, Yiqiang;Zhang, Wei
    • Journal of Computing Science and Engineering
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    • v.9 no.4
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    • pp.177-189
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    • 2015
  • High-performance processors using Non-Uniform Cache Architecture (NUCA) are increasingly used to deal with the growing wire delays in multicore/manycore processors. Due to the convergence of high-performance computing with embedded computing, NUCA caches are expected to benefit high-end embedded systems as well. However, for real-time systems that use multicore processors with NUCA caches, it is crucial to bound worst-case execution time (WCET) accurately and safely. In this paper, we developed a WCET analysis approach by considering the effect of static NUCA caches on WCET. We compared the WCET in real-time applications with different topologies of static NUCA caches. Our experimental results demonstrated that the static NUCA cache could improve the worst-case performance of realtime applications using multicore processor compared to the cache with uniform access time.

Simulation of Material Properties of Amorphous Carbon Nitride with Non-uniform Nitrogen Distribution

  • Lu, Y.F.;He, Z.F.
    • Transactions on Electrical and Electronic Materials
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    • v.2 no.3
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    • pp.1-6
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    • 2001
  • A simulation method is proposed to study the amorphous structure of carbon nitride. The material properties of a non-uniform nitrogen distribution in an amorphous CN matrix can be studied. The cohesive energy of a group of randomly generated atoms can be minimized to find the relative positions of atoms. From the calculated configuration of atoms, many properties of amorphous carbon nitride can be calculated such as bulk modulus, P-V curve, sp$^3$/sp$^2$ ratio of carbon, and vibrational spectra. The calculation shows that the cohesive energy of non-uniform nitrogen distribution is lower than that of a uniform distribution. This may suggest that the regular structure of carbon nitride can at most be metastable. It is not easy to incorporate nitrogen atoms into a carbon matrix.

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