• Title/Summary/Keyword: Flows Control

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One Response from the South: Singapore's Efforts at Developing Hub Functions

  • Ho, Kong-Chong
    • Journal of the Korean Regional Science Association
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    • v.15 no.2
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    • pp.103-116
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    • 1999
  • As Asia becomes increasingly integrated economically, opportunity particularly in managing financial flows, as bases to coordinate regional production networks, and as staging points for the penetration of new markets. The paper argues for a path-dependent logic to understanding the efforts of the Singapore State in hosting hub functions. As a city-state without a national economic hinterland, Singapore's response to increasing business costs and regional competition has been to create a set of policies designed to encourage multinational companies to keep administrative control functions in Singapore while moving the more labour and land intensive production functions to nearby Malaysia and Indonesia. An understanding of the competition among cities in the Asia Pacific for hub functions must also take into account corporate strategy within particular industry dynamics. The second half of the paper provides a number of case studies to show this interplay between corporate strategy, industry dynamic and government policy.

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A Study on the Flow Characteristics in Urban Stream Using 3-D Numerical Model (3차원 수치모형을 이용한 도시하천의 흐름특성에 관한 연구)

  • Yoon, Sun-Kwon;Kim, Jong-Suk;Moon, Young-Il;Lee, Il-Ju
    • Proceedings of the Korea Water Resources Association Conference
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    • 2007.05a
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    • pp.1287-1292
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    • 2007
  • Recently, the frequency of unexpecting heavy rains has been increased due to abnormal climate and extreme rainfall. There was a limit to analyze 1D or 2D stream flow that was applied simple momentum equation and fixed energy conservation. Therefore, hydrodynamics flow analysis in rivers has been needed 3D numerical analysis for correct stream flow interpretation. In this study, CFD model on FLOW-3D was applied to stream flow analysis, which solves three dimenson RANS(Reynolds Averaged Navier-Stokes Equation) control equation to find out physical behavior and the effect of hydraulic structures. Numerical simulation accomplished those results was compared by using turbulence models such as ${\kappa}-{\varepsilon}$, RNG ${\kappa}-{\varepsilon}$ and LES. Those numerical analysis results have been illustrated by the turbulence energy effects, velocity of flow distributions, water level pressure distributions and eddy flows around the piers at Jangwall bridge in urbarn stream.

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CNC System Improvement Research of NC Lathe Abrasion-Based on User Defined Module (NC선반 절삭공구마모 문제점 보정을 위한 CNC 성능개선 시스템 연구)

  • Park, Eun-Sik;Kim, Han-Sik
    • Journal of the Korean Society of Industry Convergence
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    • v.11 no.3
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    • pp.135-140
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    • 2008
  • This paper researched about Development Cutting Tool User Defined Module Based(PMCUDMS) on Simulation that was able to adapt themselves to rapid development of software and hardware to adopt. It is basic research that develops a scheme whereby technic make property. This paper theorized about to realize Cutting Tool User Defined Module Based on Simulation which is developing CNC Software flows from building Windows XP operating system's image that is possible realtime acting and multitasking to correct. And Cutting Tool User Defined Module Based on Simulation component which was consisted of basis OS, NC Code parser, Servo Motor Control, Simulator, Man-Machine Interface.

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CMOS Inverter Design based on Double Gate Ultra-Thin Body MOSFETs

  • Park, Sang Chun;Ahn, Yongsoo
    • Proceeding of EDISON Challenge
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    • 2015.03a
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    • pp.343-346
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    • 2015
  • Ultra-thin body transistor is one of the emerging devices since it control leakage current flows through substrate. In addition, it can be operated by double gates, thus, its on/off current ratio is higher than conventional counterpart. In this paper, we design and investigate a CMOS inverter based on ultra-thin body MOSFETs to estimate its performance in real application. NEGF (non-equilibrium Green's function) method is used to obatain relationship between drain current and voltage. DC transfer is extracted from the relationship, and FO4 (fanout-of-4) propagation delay is reported as 5.1 ps estimated by a simple model.

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Windows Based Programming for Optimal Power Flow Analysis (윈도우환경을 기반으로 한 최적전력조류 프로그램 팩키지 개발)

  • Kim, Kyu-Ho;Rhee, Sang-Bong;Lee, Jae-Gyu;You, Seok-Ku
    • Proceedings of the KIEE Conference
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    • 2001.11b
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    • pp.239-242
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    • 2001
  • This paper presents a windows program package for solving security constrained OPF in interconnected power systems, which is based on the combined application of evolutionary programming(EP) and sequential quadratic programming(SQP). The objective functions are the minimization of generation fuel costs and system power losses. The control variables are the active power of the generating units, the voltage magnitude of the generator, transformer tap settings and SVC setting. The state variables are the bus voltage magnitude, the reactive power of the generating unit, line flows and the tie line flow. In OPF considering security, the outages are selected by contingency ranking method. The resulting optimal operating point has to be feasible after outages such as any single line outage(respect of voltage magnitude, reactive power generation and power flow limits). The OPF package proposed is applied to 10 machines 39 buses model system.

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Optimal Power Flow considering Security in Interconnected Power Systems (연계계통에서 안전도제약을 고려한 최적전력조류)

  • Kim, Kyu-Ho;Lee, Jae-Gyu;Rhee, Sang-Bong;You, Seok-Ku
    • Proceedings of the KIEE Conference
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    • 2001.07a
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    • pp.194-196
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    • 2001
  • This paper presents a hybrid algorithm for solving security constrained OPF in interconnected power systems, which is based on the combined application of evolutionary programming (EP) and sequential quadratic programming (SQP). The objective functions are the minimization of generation fuel costs and system power losses. In OPF considering security, the outages are selected by contingency ranking method. The control variables are the active power of the generating units, the voltage magnitude of the generator, transformer tap settings and SVC setting. The state variables are the bus voltage magnitude, the reactive power of the generating unit, line flows and the tie line flow. The method proposed is applied to the modified IEEE 14buses model system.

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Control of the Motions of Particles in Microfluidic System (미세유동시스템 내에서의 입자의 위치제어 연구)

  • Heo, Yun Seok
    • Journal of the Korean Society for Precision Engineering
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    • v.31 no.6
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    • pp.521-525
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    • 2014
  • Circulating tumor cells (CTCs) in the bloodstream of cancer patients provide an accessible source for detection, characterization, and monitoring of nonhematological cancers. The effectiveness of the CTC-Chip for the isolation of ovarian cancer cells was demonstrated by adapting the herringbone-chip (HB-Chip). The motions of the particles on the HB chip were simulated by a unique combination of buoyant, gravitational forces, and helical flows with a computational modeling. The motions of cells are demonstrated by applying polystylene bead and ovarian cancer cells into the microfabricated HB-Chip. The experimental results from beads and cells are well accordance with the simulated ones, as previously reported by Toner group. Thus, I expect that these modeling and experimental skills will play key roles in the clinical applications on CTC isolation as well as the basic research on characterization of CTCs under flow.

Effects of Natural Convection Instability on Membrane Performance in Dead-end and Cross-flow Ultrafiltration

  • Youm, Kyung-Ho;Anthony G. Fane
    • Proceedings of the Membrane Society of Korea Conference
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    • 1995.04a
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    • pp.6-10
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    • 1995
  • An inevitable problem feature of membrane processing is concentration polarization (CF) which is a result of the accumulation of retained solutes at the membrane surface. In ultrafiltration (UF), this accumulation can lead to fouling due to the irreversible deposition of macromolecules both at the membrane surface and in the membrane pores. To reduce or control CP and folding, many possible methods have been considered [1]. One of the most effective approaches is to induce fluid instability near the membrane surface by using pusation flow [2, 3], Taylor [4] and Dean [5, 6] vortex flows. Winzeler and Belfort [6] have comprehensively reviewed several possible attempts to use fluid instabihties for improved membrane performance.

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An Empirical Investigation of Agency Costs in the Determination of Performance of Pakistani Nonfinancial Sector

  • Siddiqui, Muhammad Ayub;Afzal, Usman
    • Journal of Distribution Science
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    • v.10 no.5
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    • pp.19-28
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    • 2012
  • The study examines the performance and its relationship with capital structure and agency cost with respect to the industrial configurations and economic groups of Pakistan Economy. The study employs data set of 334 listed joint stock companies from the nonfinancial sectors for the period of 1999-2009 from cotton and textile, engineering, chemical, sugar, cement, fuel and energy, paper and board, transport and communication, and miscellaneous economic groups. Pooled data from the Panel data methodology has been applied to observe the significance of different performance measures through determinant of capital structure and agency costs with special focus on the leverage and cash flows as the direct determinant and interactive variables. The empirical test results using redundant variable tests demonstrate support for agency theory in the context of Pakistan's industrial configurations. The implications of the study point towards more investigations on the subject using industrial configurations as control and moderating variables.

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Design of the Scheduler using the Division Algorithm Based on the Time Petri net (타임 패트리넷 기반의 분할 알고리즘을 이용한 스케쥴러 설계)

  • 송유진;이종근
    • Journal of the Korea Society for Simulation
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    • v.12 no.2
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    • pp.13-24
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    • 2003
  • In this study, we propose a scheduling analysis method of the Flexible management system using the transitive matrix. The Scheduling problem is a combination-optimization problem basically, and a complexity is increased exponentially for a size of the problem. To reduce an increase of a complexity, we define that the basic unit of concurrency (short BUC) is a set of control flows based on behavioral properties in the net. And we propose an algorithm to divide original system into some BUC. To sum up, we divide a petri net model of the Flexible management system Into the basic unit of concurrency through the division algorithm using the transitive matrix. Then we apply it to the division-scheduling algorithm to find an efficient scheduling. Finally, we verify its efficiency with an example.

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