• Title/Summary/Keyword: Void Problem

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A Study on Korean Plastic Characteristics Expressed in Modem Costume - Laying Stress on the Concept of Void, Trait de Korean Painting - (현대 복식에서 표현된 한국적 조형 특성 연구 - 한국 회화의 운필, 여백의 개념을 중심으로 -)

  • Kim, Mi-Gap;Yang, Sook-Hi
    • The Research Journal of the Costume Culture
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    • v.15 no.6
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    • pp.965-981
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    • 2007
  • Since the latter half of 20 century, in Korea, there are many discussions on the identity of Korean itself in several divisions, in which the discussion on the identity in the part of the costume or the part of the art reflecting the life, is the subject which must not fail to be noticed. So, we try to study the common structure manifested in the Korean painting and the costume as a part of basic recognition of problems and the way of problem-solving for the research on the Koran formative characteristics. The method and the process of this study is first, to consider the characteristics of the plastic and style of the Oriental arts and the Occidental arts by discourse implicate the difference between Oriental and Occidental view and the recognition of the body in the two worlds. And in the study we try to apprehend the dynamic modern artistic value of Korean style through assimilation between the Korean style and Baroque style according to the theory of $W\ddot{o}lfflin$ about the classical style and Baroque style. We will describe the Korean identity by analyzing the Korean plasticity with the Occidental style of dress and paintings reflecting the Occidental culture and thought and the Oriental things, and modern paintings and dress in the present age. As a result, we can try to recherche the way of use of new design for the identity of Korean style, in the concept of the ellipsis, repetition of the retrait, obscur silhouette, and superimposition.

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An Improved Energy Aware Greedy Perimeter Stateless Routing Protocol for Wireless Ad Hoc Network (무선 Ad Hoc 네트워크를 위한 개선된 위치정보 기반의 에너지를 고려한 라우팅 프로토콜)

  • Kim, Hak-Je;Yoon, Won-Sik
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.46 no.11
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    • pp.25-31
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    • 2009
  • In this paper we propose an improved energy aware greedy perimeter stateless routing protocol (EAGPSR) for wireless ad hoc network. The existing greedy perimeter stateless routine (GPSR) has some problems with overloaded node and void situation. The improved EAGPSR protocol is proposed to remedy these problems. It also gives the solution for the fundamental problem in geographical routine called void communication. It considers two parameters (Residual Energy of battery and distance to the destination) for the next hop selection. In order to use efficiently limited-energy of node in wireless ad hoc network, network lifetime is focused. To evaluate the performance of our protocol we simulated EAGPSR in ns-2. The simulation results show that the proposed protocol achieves longer network lifetime compared with greedy perimeter stateless routing (GPSR) and the existing Energy aware greedy perimeter stateless routing protocol (EAGPSR).

Material Design and Analysis of Coronary Artery Stents (관상동맥혈관용 스텐트의 구조해석과 재료설계)

  • Park, Joong-Gwun;Kang, Tae-Won;Lee, Kee-Sung;Kim, Tae-Woo
    • Journal of the Korean Ceramic Society
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    • v.44 no.7
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    • pp.362-367
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    • 2007
  • Stent is a tiny structure made with either ceramic coating and/or bare metal. Being approximately $1{\sim}2 mm$ in diameter, it consists of holes, slots, or void space and is designed to cover entire medical lesions. Stent implantation into patients' arteries has been practiced for a little more than a decade in order to widen the blocked artery. The adoption of the stent has significantly improved the efficacy when compared with the previous medical practice by balloon angioplasty alone. Yet better biomedical performance of the stent is being demanded in order to eliminate the still existing problem of artery restenosis, which means the artery becomes narrowed again. Recent literature survey shows researches on ceramic coatings onto the stent surface, or material design to improve the mechanical response of the stent. This study focuses more on the material design and mechanical analysis. The results showed that the void configuration within the stent affects the mechanical response significantly. The rectangular shape was found to yield expansion at a relatively lower pressure than the elliptical slot for a slotted tube stent. The present results, when combined with research on coating at the stent surface, may provide stents with improved bio-medical performance.

DT-GPSR: Delay Tolerant-Greedy Perimeter Stateless Routing Protocol (DT-GPSR: 지연감내형 GPSR 라우팅 프로토콜)

  • Nam, Jae-Choong;Cho, You-Ze
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.2
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    • pp.189-197
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    • 2016
  • Mobile ad-hoc networks (MANETs) experience frequent link disconnections due to non-uniform node distribution and mobility. Thus, end-to-end path establishment-based routing protocols cause frequent transmission failures in MANETs, resulting in heavy control messages for path reestablishment. While location-based MANET routing protocols, such as Greedy Perimeter Stateless Routing (GPSR), use location information to forward messages in a hop-by-hop routing fashion without an end-to-end path establishment procedure, such protocols encounter communication void problems when message forwarding to the next hop fails due to the absence of a relay node. Therefore, to solve this problem, this paper proposes a Delay Tolerant-GPSR (DT-GPSR) protocol, which combines Delay Tolerant Networking (DTN) technology with the GPSR protocol. The performance of DT-GPSR is compared with the performances of the original GPSR and PRoPHET routing protocols through simulation using NS-2. The simulation results confirm that DT-GPSR outperforms GPSR and PRoPHET in terms of the message delivery ratio and message delivery delay.

An Interpretation of Soil Water Retention Curves of Weathered Soils Using Micro-Membrane (마이크로 멤브레인을 이용한 풍화토의 함수특성곡선 분석)

  • Oh, Seboong;Kim, Seongjin
    • Journal of the Korean Geotechnical Society
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    • v.37 no.1
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    • pp.17-27
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    • 2021
  • It takes a long period to conduct the test on soil water retention curve (SWRC) in unsaturated soils. To improve such a problem, the high air entry disk has been replaced by micro-membrane. After the soil water retention test, the results by the micro-membrane were compared with those by the ceramic disk. Multiple samples in 5 regions were used to validate that SWRCs by micro-membrane are equivalent to those by ceramic disk. Therefore, a quick procedure based on micro-membrane has been developed, which makes it available to acquire much soil water retention data. The data of SWRCs were obtained for total 29 samples using ceramic disk or micro-membrane. For Korean weathered soils, the unsaturated hydraulic characteristics are sorted by three groups. Based on van Genuchten model, the group is divided by the parameter n, and the value of n could be correlated to the void ratio as each function.

Experimental research on flow regime and transitional criterion of slug to churn-turbulent and churn-turbulent to annular flow in rectangular channels

  • Qingche He;Liang-ming Pan;Luteng Zhang;Wangtao Xu;Meiyue Yan
    • Nuclear Engineering and Technology
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    • v.55 no.11
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    • pp.3973-3982
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    • 2023
  • As for two-phase flow in rectangular channels, the flow regimes especially like churn-turbulent and annular flow are significant for the physical problem like Countercurrent Flow Limitation (CCFL). In this study, the rectangular channels with cross-sections of 4 × 66 mm, 6 × 66 mm, 8 × 66 mm are adopted to investigate the flow regimes of air-water vertical upward two phase flow under adiabatic condition. The gas and liquid superficial velocities are 0 ≤ jg ≤ 20m/s and 0.25 ≤ jf ≤ 3m/s respectively which covering bubbly to annular flow. The flow regimes are identified by random forest algorithm and the flow regime maps are obtained. As the results, the transitional void fraction from slug to churn turbulent flow fluctuate from 0.47 to 0.58 which is significantly affected by the dimensional size of channel and flow rate. Besides, the void fraction at transitional points from churn-turbulent (slug) to annular flow are 0.66-0.67, which are independent with the gap size. Furthermore, a new criteria of slug to churn-turbulent flow is established in this study. In addition, by introducing the interfacial force model, the criteria of churn-turbulent (slug) flow to annular flow is verified.

Mixed Design of Grouting Materials for Settlement Restoration Using Micro Cement (마이크로시멘트를 이용한 침하복원용 그라우팅재료의 배합 설계)

  • Lee, Il-Wha;Lee, Sung-Jin;Yun, Won-Min;Park, Sung-Ki
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.1786-1792
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    • 2011
  • If the concrete track is settled excessively, it must be restored or reinforced immediately. Especially, reinforcement/restoration method should be applied without affecting on train operation. To deal with this problem, special equipment, process and material should be prepared. This paper suggest a special mixing ratio to restore the settled concrete track. Materials are classified the quick hardening mortar and the middle hardening mortar. The quick hardening mortar is used to restore the settled track and the middle hardening mortar is used to fill the void. These materials must have the appropriate gel time(1-40sec) and compressive strength($5kg/cm^2$). Various compounds is used and the micro cement is used as a main base.

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Structural Topology Optimization for the Natural Frequency of a Designated Mode

  • Lim, O-Kaung;Lee, Jin-Sik
    • Journal of Mechanical Science and Technology
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    • v.14 no.3
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    • pp.306-313
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    • 2000
  • The homogenization method and the density function method are common approaches to evaluate the equivalent material properties for design cells composed of matter and void. In this research, using a new topology optimization method based on the homogenized material with a penalty factor and the chessboard prevention strategy, we obtain the optimal layout of a structure for the natural frequency of a designated mode. The volume fraction of nodes of each finite element is chosen as the design variable and a total material usage constraint is imposed. In this paper, the subspace method is used to evaluate the eigenvalue and its corresponding eigenvector of the structure for the designated mode and the recursive quadratic programming algorithm, PLBA algorithm, is used to solve the topology optimization problem.

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A Study about Mechanical Properties of GFRP Laminates depending on Fiber Volume Fraction (섬유체적함유율의 영향에 따른 GFRP적층판의 기계적 특성에 관한 연구)

  • 국중석
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2003.10a
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    • pp.225-230
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    • 2003
  • Domestic small and medium ship companies have lack of leisure boat technologies and especially they have a problem about its low performance because of the overweight of boat hull. So it is necessary to have alternative manufacturing process to improve the mechanical properties of composite material. In this study, a vacuum curing system was developed as an alternative manufacturing process and then changed the fiber volume fractions of GFRP laminates. The properties of GFRP laminates such as void contents, Young's modulus and fracture toughness were determined for various fiber volume fractions.

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Optimizing structural topology patterns using regularization of Heaviside function

  • Lee, Dongkyu;Shin, Soomi
    • Structural Engineering and Mechanics
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    • v.55 no.6
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    • pp.1157-1176
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    • 2015
  • This study presents optimizing structural topology patterns using regularization of Heaviside function. The present method needs not filtering process to typical SIMP method. Using the penalty formulation of the SIMP approach, a topology optimization problem is formulated in co-operation, i.e., couple-signals, with design variable values of discrete elements and a regularized Heaviside step function. The regularization of discontinuous material distributions is a key scheme in order to improve the numerical problems of material topology optimization with 0 (void)-1 (solid) solutions. The weak forms of an equilibrium equation are expressed using a coupled regularized Heaviside function to evaluate sensitivity analysis. Numerical results show that the incorporation of the regularized Heaviside function and the SIMP leads to convergent solutions. This method is tested using several examples of a linear elastostatic structure. It demonstrates that improved optimal solutions can be obtained without the additional use of sensitivity filtering to improve the discontinuous 0-1 solutions, which have generally been used in material topology optimization problems.