• Title/Summary/Keyword: hybrid zone

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Selective On-demand Zone Routing Protocol for Large Scale Mobile Ad-hoc Networks (대규모 Ad-hoc 네트워크 환경에서 트래픽 감소를 위한 선택적 on-demand 라우팅 기법에 관한 연구)

  • Lee, Jae-Ho;Eom, Doo-Seop
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.6B
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    • pp.443-452
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    • 2012
  • In Mobile Ad-hoc Networks, previous routing protocols classified into proactive and reactive approach respectively have pros and cons under the use of applications and environment. Moreover, to integrate their advantages in case by case, hybrid approach is consistently researched, and Zone Routing Protocol (ZRP) was motivating many recent hybrid protocols. ZRP uses proactive routing to the node located within the zone defined by the specific number of hops, while it uses reactive routing to other nodes. However, in ZRP, because proactive routing is applied only within the zone defined by the number of hops, the zone is formed regardless of whether real data communication occurred frequently or not. In this paper, we propose a new hybrid routing scheme which employs the zone method but forms customized zone considering traffic load and number of hops, by a new decision method named Dynamic Zone Decision (DZD). Additionally, we analyze the performance of the proposed scheme, comparing with the previous proactive, reactive, and hybrid routings.

Experimental Study on the Shear Capacity of the U-Flanged Truss Hybrid Beam With Reinforced End Zone (단부 보강에 따른 U-플랜지 트러스 복합보의 전단 내력에 관한 실험연구)

  • Kim, Young Ho;Park, Sung Jin;Oh, Myoung Ho
    • Journal of Korean Association for Spatial Structures
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    • v.21 no.1
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    • pp.71-78
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    • 2021
  • The U-flanged truss hybrid beam is a new composite beam made by pouring concrete into the U-flanged truss beam. In this study, an experimental study was performed to verify the shear capacity of U-flanged truss hybrid beams with the newly developed end reinforcement details. For all specimens, the maximum shear strength was determined by shear failure of concrete in the loading point The detail reinforced with stirrups at the end zone can exhibit the greatest shear strength, but the method of reinforcing the end zone using vertical steel plates, which is a relatively easy method to manufacture, is considered to be the most effective detail in terms of shear strength and ductility. Also, in the case of U-flanged truss hybrid beams reinforced with vertical steel plates at the end zone, the shear strength can be evaluated on the safety side by using the Korea Design Standard formula.

Mechanical Property of Ultra Fine Grained Steel Weld by Hybrid Welding (하이브리드 용접에 의한 세립강 용접부의 기계적 성질에 관한 연구)

  • Dong, H.W.;Ahn, Y.S.
    • Journal of Power System Engineering
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    • v.15 no.1
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    • pp.45-50
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    • 2011
  • The effect of Mn and Ti contents in filler wire on the microstructure and mechanical property of weld metal has been investigated after hybrid welding with ultra fine grained (UFG) steel. The microstructure and distribution of alloy compositions at the top region of weld zone were quite different with those at the bottom region after hybrid welding. The bottom region of weld zone contained higher Mn and Ti contents, and consequently the hardness of bottom region was higher than that of top region. With the increase of Mn and Ti contents in filler wire, the volume percent of acicular ferrite in weld metal decreased, and the weld zone showed higher hardness and better impact property.

Microstructure Evolution of UFG Steel Weld by Hybrid and Laser Welding (하이브리드 용접과 레이저 용접에 의한 세립강 용접부의 미세조직변화에 관한 연구)

  • Dong, H.W.;Lee, M.Y.;Ahn, Y.S.
    • Journal of Power System Engineering
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    • v.14 no.3
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    • pp.58-63
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    • 2010
  • A laser beam welding and an electric arc welding were combined, and the positive points of each welding method are drawn such as high speed, low thermal load, deep penetration, and high productivity. The fiber laser-MIG conjugated welding. namely the hybrid welding has been studied mainly for the automation industry of a pipeline welding. In this study, the MIG welding was combined with a fiber laser welding to make up the hybrid welding. The weld shapes, microstructures and mechanical properties for weld zones after the hybrid welding or only fiber laser welding were investigated on the 700 MPa grade Ultra Fine Grained(UFG) high strength steel. The amount of acicular ferrite in weld metals and HAZ(heat affected zone) was observed larger after hybrid welding compared with after only laser welding. The Vickers hardness of the top area of the fusion zone after fiber laser welding was higher compared with after hybrid welding.

Effect of Diaphragm Thickness on Regression Rate Improvement in Hybrid Rocket Motor (다이아프램 두께 변화에 따른 하이브리드 로켓의 후퇴율 향상에 관한 연구)

  • Ryu, Sung-Hoon;Oh, Ji-Sung;Moon, Keun-Hwan;Kim, Hak-Chul;Moon, Hee-Jang;Kim, Jin-Kon
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.23 no.4
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    • pp.1-5
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    • 2015
  • In this work, a study was conducted to investigate the effect of diaphragm thickness on the regression rate of the hybrid rocket motor. To observe the flow pattern and the recirculation zone, visualizations of combustion chambers with different diaphragm thickness (5mm, 10mm) were performed. It was found that the case with 5 mm thickness had a larger recirculation zone and therefore, had a higher regression rate than the case with 10mm thickness due to the increased residence time and heat transfer toward the fuel surface. Finally, it was concluded that the thickness of diaphragm can be a critical parameter for the enhancement of the regression rate.

A Study of Hybrid Ventilation System applying to an Apartment House (공동주택용 하이브리드 환기설비에 관한 연구)

  • Yi, Seong-Hwan
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.1137-1143
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    • 2006
  • The purpose of this research lays on examining the adequacy of the hybrid ventilation system. The hybrid ventilation system must satisfy the next to be used. Firstly, the cold-draft phenomenon must not exist in the occupied zone. Secondly, the condensation must not happen on the surfaces of vents. Thirdly, the flow of make-up air must be happened in an each space by exhausted air of a rest room and living room. We used an examination and CFD method to verify these. Trough the examination of air-vents, We confirmed that the cold-draft to be induced by make-up air does not happen and could not find the condensation in the limits of outdoor temperature higher than 265K. Through CFD simulation, We confirmed that the rapid temperature change existed only within 0.5m the occupied zone and the flow of air was happened in an each space by only exhausted air in the rest room and living room. Consequently, the hybrid system is possible method to an apartment house.

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A Similar Price Zone Determination of Public Land Price Using a Hybrid Clustering Technique (평균연결법과 K-means 혼합클러스터링 기법을 이용한 공시지가 유사가격권역의 설정)

  • Yi Seong-Kyu;Park Soo-Hong;Hong Sung-Eon
    • Journal of the Korean Geographical Society
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    • v.41 no.1 s.112
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    • pp.121-135
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    • 2006
  • Even though the similar land price zone is very important element in the public land appraisal procedure, the concept is implicitly described and applied into the actual land appraisal system. This situation makes it worse when applying for the automatic selection of a comparative standard land parcel. In addition, the division of similar land price zones requires the objective and reasonable process for improving ALPAS(Automatic land Price Appraisal System), which becomes an issue today. To solve the similar land price zone determination problem that is caused by the lack of objective numerical standard, this study proposed a similar land price zone determination method using a hybrid clustering technique. Results showed that this hybrid clustering method that applied into the test area could easily detect similar land price zones with considerable accuracy levels, which are verified with some test statistics and real comparative standard land parcels done by manually.

Damage of bonded, riveted and hybrid (bonded/riveted) joints, Experimental and numerical study using CZM and XFEM methods

  • Ezzine, M.C.;Amiri, A.;Tarfaoui, M.;Madani, K.
    • Advances in aircraft and spacecraft science
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    • v.5 no.5
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    • pp.595-613
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    • 2018
  • The objective of our study is to analyze the behavior of bonded, riveted and hybrid (bonded / riveted) steel / steel assemblies by tensile tests and to show the advantage of a hybrid assembly over other processes. the finite element method with the ABAQUS numerical code was used to model the fracture behavior of the different assemblies. Cohesive zone models (CZM) have been adopted to model crack propagation in bonded joints using a bilinear tensile separation law implemented in the ABAQUS finite element code. The riveted assemblies were modeled with the XFEM damage method identified in this ABAQUS numerical code. Both CZM and XFEM methods are combined to model hybrid assemblies. The results are consistent with the experimental results and make it possible to guarantee the validity of the applied numerical model. The use of a hybrid assembly shows a high resistance compared to other conventional methods, where the number of rivets has been highlighted. The use of the hybrid assembly improves mechanical strength and increases service life compared to a single lap joint and a riveted joint.

Optimization of Battery Power Distribution to Improve Fuel Consumption of Fuel Cell Hybrid Vehicle (연료전지 하이브리드 차량의 연비향상을 위한 배터리 동력분배 최적화)

  • Lee, Dong Sup
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.3
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    • pp.397-403
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    • 2013
  • The demand for eco-friendly and higher fuel economy vehicles has helped develop eco-friendly and fuel-efficient vehicles such as hybrid vehicles. In a hybrid vehicle, the change in the battery charge after driving should be added to the fuel consumption as the equivalent fuel usage based on its own characteristics. Thus, the fuel efficiency of a hybrid vehicle cannot be improved simply by increasing the battery capacity. In this study, I attempt to improve the total fuel economy of a hybrid vehicle, including the equivalent fuel consumption, by modeling a fuel cell hybrid vehicle using Matlab Simulink, analyzing the usage zone of the fuel cell with the existing control strategy, and optimizing the power distribution of the battery and fuel cell in the main usage zone of the fuel cell.

Numerical Simulation of Wave Forces acting on Fixed Offshore Structures Using Hybrid Scheme (하이브리드 기법을 이용한 고정된 해양구조물에 작용하는 파랑하중에 관한 수치 시뮬레이션)

  • Nam, Bo-Woo;Hong, Sa-Young;Kim, Yong-Hwan
    • Journal of Ocean Engineering and Technology
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    • v.24 no.6
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    • pp.16-22
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    • 2010
  • In this paper, the diffraction problems for fixed offshore structures are solved using a hybrid scheme. In this hybrid scheme, potential-based solutions and the Navier-Stokes-based finite volume method (FVM) with a volume-of-fluid (VOF) method are combined. We introduce a buffer zone for efficient wave-making and damping. In this buffer zone, the near field solution from FVM-VOF is gradually changed to Stokes' 2nd order wave solutions. Three different models, including the truncated cylinder, sphere, and wigleyIII model, are numerically investigated in regular waves with a wave steepness of 1/30. The efficiency and accuracy of the hybrid scheme are numerically validated from results using different domain sizes and buffer zones. The wave exciting forces from the FVM-VOF simulations are compared with experiments and potential-based solutions from the higher-order boundary element method (HOBEM). This comparison shows good agreement between the hybrid scheme and potential-based solutions.