• Title/Summary/Keyword: concept combination

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The Study of Training Scenario for the KA-32T Helicopter Simulator (KA-32T 헬리콥터 시뮬레이터를 위한 훈련 시나리오 연구)

  • Jeong, Ji-Hoon;Kang, Seung-On;Lee, Ki-Hak;Park, Yong-Jin;Ko, Kang-Myung;Ham, Dae-Young;Lee, Dong-Ho;Jun, Hyang-Sig;Choi, Hyung-Sik
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.16 no.2
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    • pp.28-35
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    • 2008
  • The purpose of this study is to develop a training scenario for KA-32T helicopter simulator. First, the concept of training scenario are classified into training elements and training information. Secondly, the training elements are defined according to the property of each element: flight phase, situation, and environment. The main mission of KA-32T on the operation of KFS(Korea Forest Service) is the forest fire extinguishment mission, and it is divided into the two disciplines: water supply and water discharge. Finally the mission scenario for two disciplines are defined and developed as the combination of the normal procedures of training scenario and the mission procedures.

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Design and Analysis of State-of-the-Art Technologies for Development of Floating Photovoltaic System (수상태양광 발전시스템 설계 및 요소기술 분석)

  • Jin, Taeseok
    • Journal of the Korean Society of Industry Convergence
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    • v.17 no.4
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    • pp.227-233
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    • 2014
  • Information presented in this study is intended to inform candidates as they prepare to design and structure the floatovoltaics solar power system. A developed floatovoltaics solar power generation results from the combination of PV plant technology and PV floating technology. This floating-based PV system is a new concept for PV development. The PV floating technology opens new opportunities to give value to unused areas so far while preserving valuable land for more adapted activities. Therefore the land-use conflicts are avoided and the environmental impact is minimized. Therefore the technology offers an interesting opportunity to regions facing on drought during summer time without any negative impact to the eco-system. This study describe the basic components of a floatovoltaics solar power system. A typical system consist of floating system and solar modules, a control device, rechargeable batteries, a load or device and the associated electrical connections. The floating system is specifically designed to keep all metallic components above water leaving only 100% recyclable, closed cell foam filled HDPE plastic floats in contact with the water. As the first case that can maximize the power generation efficiency of PV internationally, it is expected that this study will be utilized as a primary guide for future development of floating type PV system.

Efficient routing in multicast mesh by using forwarding nodes and weighted cost function

  • Vyas, Kapila;Khuteta, Ajay;Chaturvedi, Amit
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.12
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    • pp.5928-5947
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    • 2019
  • Multicast Mesh based Mobile Ad-hoc NETworks (MANETs) provide efficient data transmission in energy restraint areas without a fixed infrastructure. In this paper, the authors present an improved version of protocol SLIMMER developed by them earlier, and name it SLIMMER-SN. Most mesh-based protocols suffer from redundancy; however, the proposed protocol controls redundancy through the concept of forwarding nodes. The proposed protocol uses remaining energy of a node to decide its energy efficiency. For measuring stability, a new metric called Stability of Node (SN) has been introduced which depends on transmission range, node density and node velocity. For data transfer, a weighted cost function selects the most energy efficient nodes / most stable nodes or a weighted combination of both. This makes the node selection criteria more dynamic. The protocol works in two steps: (1) calculating SN and (2) using SN value in the weighted cost function for selection of nodes. The study compared the proposed protocol, with other mesh-based protocols PUMA and SLIMMER, based on packet delivery ratio (PDR), throughput, end-to-end delay and average energy consumption under different simulation conditions. Results clearly demonstrate that SLIMMER-SN outperformed both PUMA and SLIMMER.

A thought on Korea food culture and collectivity+ (한국인의 공동체의식과 식문화에 대한 소고(小考)+)

  • Oh, Se-Young;Lee, Hun
    • Journal of the Korean Society of Food Culture
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    • v.19 no.5
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    • pp.556-565
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    • 2004
  • This study examined dietary culture in Korea regarding collectivism through literature review. Based on the evidence from the origin of lineage and traditional customs, the Koreans' traditional collectivity appeared to have been grounded upon the northen nomadic culture emphasizing sentimental collectivity and harmonized with the characteristics of southern agrarian society related to mutual support and sociability. The inseparable relationship between collectivity and food was well revealed in the occasions such as rice-planting, kimchi and jang makings in which pooled labor was common as well as the gathering of mutual aid association. In these occasions, foods were offered and shared among members. Food sharing was a main activity and almost play a central role regarding the promotion of friendly relations among each other. In sacrificial memorials, food sharing was extended not only to the live persons but also to the passing spirits. Collectivity was also disclosed in the eating or table manners of Koreans. Koreans quite literally share food at every meal since the side dishes placed centrally on the table. The taste of Korean foods is completed inside the mouth by mixing foods with various combination, which let people create their own choice of taste. Therefore, the collectivity manners at the table appeared to be harmonized with individual freedom of creating his/her own taste of foods. The collectivity is still a very important concept in modem Korean dietary culture, as reflected by an increase of restaurants sewed shared dishes.

Development of a Mixed Chaotic Electric Arc Furnace Model (전력 품질 해석을 위한 개선된 전기아크로 모델 개발)

  • Jang, Gil-Soo;Wang, Weiguo;Lee, Byongjun;Kwon, Sae-Hyuk
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.50 no.2
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    • pp.90-95
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    • 2001
  • Electric arc furnaces (EAFs) has a process to cause the degradation of the electric power quality such as voltage flicker. In order to adequately understand and analyze the effects on the power system from these loads, obtaining an accurate representation of the characteristics of the loads is crucial. In this paper, a mixed chaotic EAF model to represent the low frequency and high frequency variations of the arc current respectively has been proposed. The Lorenz system may contribute to the low frequency components of arc current and the logistic equation may contribute to the high frequency components, and the proposed mixed model will be a combination of both Lorenz and logistic model. The concept of chaotic parameters, such as chaotic resistance, inductance of admittance has been also proposed for the characterization of arc furnace operation and the highly nonlinear physical processes. The power quality indices are calculated from the simulated waveforms and compared with the actual power quality indices statistics in order to illustrate the model's capabilities.

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Efficient models for analysis of a multistory structure with flexible wings

  • Moon, Seong-Kwon;Lee, Dong-Guen
    • Structural Engineering and Mechanics
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    • v.13 no.5
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    • pp.465-478
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    • 2002
  • This study lays emphasis on the development of efficient analytical models for a multistory structure with wings, including the in-plane deformation of floor slabs. For this purpose, a multistory structure with wings is regarded as the combination of multistory structures with rectangular plan and their junctions. In addition, a multistory structure with a rectangular plan is considered to be an assemblage of two-dimensional frames and floor slabs connecting two adjacent frames at each floor level. This modeling, concept can be easily applied to multistory structures with plans in the shape of L, T, Y, U, H, etc. To represent the in-plane deformation of floor slabs efficiently, a two-dimensional frame and the floor slab connecting two adjacent frames at each floor level are modeled as a stick model with two degrees of freedom per floor and a stiff beam with shear deformations, respectively. Three models are used to investigate the effect of in-plane deformation of the floor slab at the junction of wings on the seismic behavior of structures. Based on the comparison of dynamic analysis results obtained using the proposed models and three-dimensional finite element models, it could be concluded that the proposed models can be used as an efficient tool for an approximate analysis of a multistory structure with wings.

Spatial extrapolation of pressure time series on low buildings using proper orthogonal decomposition

  • Chen, Yingzhao;Kopp, Gregory A.;Surry, David
    • Wind and Structures
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    • v.7 no.6
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    • pp.373-392
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    • 2004
  • This paper presents a methodology for spatial extrapolation of wind-induced pressure time series from a corner bay to roof locations on a low building away from the corner through the application of proper orthogonal decomposition (POD). The approach is based on the concept that pressure time series in the far field can be approximated as a linear combination of a series of modes and principal coordinates, where the modes are extracted from the full roof pressure field of an aerodynamically similar building and the principal coordinates are calculated from data at the leading corner bay only. The reliability of the extrapolation for uplift time series in nine bays for a cornering wind direction was examined. It is shown that POD can extrapolate reasonably accurately to bays near the leading corner, given the first three modes, but the extrapolation degrades further from the corner bay as the spatial correlations decrease.

An experimental study of vibration control of wind-excited high-rise buildings using particle tuned mass dampers

  • Lu, Zheng;Wang, Dianchao;Masri, Sami F.;Lu, Xilin
    • Smart Structures and Systems
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    • v.18 no.1
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    • pp.93-115
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    • 2016
  • A particle tuned mass damper (PTMD) system is the combination of a traditional tuned mass damper (TMD) and a particle damper (PD). This paper presents the results of an experimental and analytical study of the damping performance of a PTMD attached to the top of a benchmark model under wind load excitation. The length ratio of the test model is 1:200. The vibration reduction laws of the system were explored by changing some system parameters (including the particle material, total auxiliary mass ratio, the mass ratio between container and particles, the suspending length, and wind velocity). An appropriate analytical solution based on the concept of an equivalent single-unit impact damper is presented. Comparison between the experimental and analytical results shows that, with the proper use of the equivalent method, reasonably accurate estimates of the dynamic response of a primary system under wind load excitation can be obtained. The experimental and simulation results show the robustness of the new damper and indicate that the damping performance can be improved by controlling the particle density, increasing the amount of particles, and aggravating the impact of particles etc.

Micro-Chemical Structure of Polyaniline Synthesized by Self-Stabilized Dispersion Polymerization

  • NamGoong, Hyun;Woo, Dong-Jin;Lee, Suck-Hyun
    • Macromolecular Research
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    • v.15 no.7
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    • pp.633-639
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    • 2007
  • A variety of NMR techniques were applied to the micro-chemical structural characterization of polyanilines prepared via an efficient synthetic method in a self-stabilized dispersion medium in which the polymerization was conducted in a heterogeneous organic/aqueous biphasic system without any stabilizers. Here, the monomer and growing polymer chain were shown to function simultaneously as a stabilizer, imparting compatibility for the dispersion of the organic phase, and as a form of flexible template in an aqueous reaction medium. Polymerizations predicated on this concept generated polyanilines with a low defect content: solution state $^{13}C-NMR$ and solid $^{13}CDD/CP/MAS$ spectroscopy indicated that the synthesized HCPANi and its soluble derivative, HCPANi-t-BOC, evidenced distinctly different NMR spectra with fewer side peaks, as compared to conventionally prepared PANis, and the complete structural assignments of the observed NMR peaks could be determined via the combination of both 1D and 2D techniques. Ortho-linked defects in HCPANi were estimated to be as low as 7%, as shown by a comparison of the integration of the carbonyl carbon resonance peaks.

FATIGUE LIFE ASSESSMENT OF REACTOR COOLANT SYSTEM COMPONENTS BY USING TRANSFER FUNCTIONS OF INTEGRATED FE MODEL

  • Choi, Shin-Beom;Chang, Yoon-Suk;Choi, Jae-Boong;Kim, Young-Jin;Jhung, Myung-Jo;Choi, Young-Hwan
    • Nuclear Engineering and Technology
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    • v.42 no.5
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    • pp.590-599
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    • 2010
  • Recently, efficient operation and practical management of power plants have become important issues in the nuclear industry. In particular, typical aging parameters such as stress and cumulative usage factor should be determined accurately for continued operation of a nuclear power plant beyond design life. However, most of the major components have been designed via conservative codes based on a 2-D concept, which do not take into account exact boundary conditions and asymmetric geometries. The present paper aims to suggest an effective fatigue evaluation methodology that uses a prototype of the integrated model and its transfer functions. The validity of the integrated 3-D Finite Element (FE) model was proven by comparing the analysis results of individual FE models. Also, mechanical and thermal transfer functions, known as Green's functions, were developed for the integrated model with the standard step input. Finally, the stresses estimated from the transfer functions were compared with those obtained from detailed 3-D FE analyses results at critical locations of the major components. The usefulness of the proposed fatigue evaluation methodology can be maximized by combining it with an on-line monitoring system, and this combination, will enhance the continued operations of old nuclear power plants.