• Title/Summary/Keyword: control mechanisms

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Performance Evaluation of Real-time Mechanisms for Real-time Embedded Linux (실시간 임베디드 리눅스의 실시간 메커니즘 성능 분석)

  • Koh, Jae-Hwan;Choi, Byoung-Wook
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.4
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    • pp.337-342
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    • 2012
  • This paper presents performance evaluation of real-time mechanisms for real-time embedded linux. First, we presents process for implementing open-source real-time embedded linux namely RTAI and Xenomai. These are real-time extensions to linux kernel and we implemented real-time embedded linux over the latest linux kernel. Measurements of executions of real-time mechanisms for each distribution are performed to give a quantitative comparison. Performance evaluations are conducted in kernel space about repeatability of periodic task, response time of Semaphore, FIFO, Mailbox and Message queue in terms of inter-task communication for each distribution. These rules can be helpful for deciding which real-time linux extension should be used with respect to the requirements of the real-time applications.

Analysis on Human Musculoskeletal Structures with Application to Design of Adjustable Spring Mechanisms (인체의 근육구조에 대한 해석과 가변스프링 메커니즘 설계로의 적용)

  • 이병주;이재훈;김희국
    • Journal of Institute of Control, Robotics and Systems
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    • v.5 no.2
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    • pp.208-219
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    • 1999
  • Springs have been employed in a wide range of mechanical systems. This work deals with the concept of an adaptable spring mechanism which can arbitrarily modulate its spring characteristics. The adaptable spring is desired for enhancing performances of various mechanical systems employing springs. We demonstrate that such adaptable springs can be realized by adapting anthropomorphic musculoskeletal structures of the human upper-extremity, which possesses highly nonlinear kinematic-coupling among redundant muscles existing in its structures. This phenomenon has been explained by several human arm models. Based on the analysis results, we propose multi-degree-of-freedom spring mechanisms resembling the musculoskeletal structure of the human upper-extremity, and verifiy the applicability of these mechanisms through simulation.

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A Piezo-driven Fine Manipulation System Based on Flexure Hinges for Manipulating Micro Parts (미세 부품 조작을 위한 탄성힌지 기반 압전소자 구동형 초정밀 머니플레이션 시스템)

  • Choi, Kee-Bong;Lee, Jae-Jong;Kim, Gee-Hong;Ko, Kuk-Won
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.9
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    • pp.881-886
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    • 2009
  • This paper presents a manipulation system consisting of a coarse/fine XY positioning system and an out-of-plane manipulator. The object of the system is to conduct tine positioning and manipulation of micro parts. The fine stage and the out-of-plane manipulator have compliant mechanisms with flexure hinges, which are driven by stack-type piezoelectric elements. In the fine stage, the compliant mechanism plays the roles of motion guide and displacement amplification. The out-of-plane manipulator contains three piezo-driven compliant mechanisms for large working range and fine resolution. For large displacement, the compliant mechanism is implemented by a two-step displacement amplification mechanism. The compliant mechanisms are manufactured by wire electro-discharge machining for flexure hinges. Experiments demonstrate that the developed system is applicable to a fine positioning and fine manipulation of micro parts.

Implementation of an Operator Model with Error Mechanisms for Nuclear Power Plant Control Room Operation

  • Suh, Sang-Moon;Cheon, Se-Woo;Lee, Yong-Hee;Lee, Jung-Woon;Park, Young-Taek
    • Proceedings of the Korean Nuclear Society Conference
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    • 1996.05a
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    • pp.349-354
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    • 1996
  • SACOM(Simulation Analyser with Cognitive Operator Model) is being developed at Korea Atomic Energy Research Institute to simulate human operator's cognitive characteristics during the emergency situations of nuclear power plans. An operator model with error mechanisms has been developed and combined into SACOM to simulate human operator's cognitive information process based on the Rasmussen's decision ladder model. The operational logic for five different cognitive activities (Agents), operator's attentional control (Controller), short-term memory (Blackboard), and long-term memory (Knowledge Base) have been developed and implemented on blackboard architecture. A trial simulation with a scenario for emergency operation has been performed to verify the operational logic. It was found that the operator model with error mechanisms is suitable for the simulation of operator's cognitive behavior in emergency situation.

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Performance Comparison between Material Flow Control Mechanisms Using Simulation (시뮬레이션을 통한 생산흐름통제시스템의 성능비교)

  • Park, Sang-Geun;Ha, Chung-Hun
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.35 no.1
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    • pp.115-123
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    • 2012
  • Material flow control mechanism is a kind of operational policy in manufacturing. It is very important because it varies throughput, throughput time, and work-in-process (WIP) under the same manufacturing resources. Many Researchers have developed various material flow control mechanisms and insisted that their mechanism is superior to others. However the experimental environment used in the performance comparison are different and impractical. In this paper, we set various manufacturing environments to fairly compare five previous material flow control mechanism : Push, Pull, CONWIP, Gated MaxWIP, and Critical WIP Loops. The simulation results show that the Push is superior to others in both of throughput and WIP if required demand is less than 80% of capacity. In addition, the performance of CONWIP and its variants are not different statistically.

Feedback Load Control Mechanism for Real-Time Web Services (실시간 웹 서비스를 위한 피드백 부하 제어 기법)

  • Jung, Suk-Yong
    • Journal of the Korea Convergence Society
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    • v.1 no.1
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    • pp.17-21
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    • 2010
  • This paper proposes a mechanism for managing overload in real-time web service system. The many previous mechanisms manage overload with controlling web request. These mechanisms can control only new web request. They don't have any control existing tasks, especially periodic tasks. We design a controller that able to meet real-time performance with controlling even periodic tasks. A feedback control system is implemented applying the proposed mechanism. And we verified the stable operation of system.

Structual Design of a Building with High Damping Provided by Deformation Amplification Mechanisms and Tuned Viscous Mass Damper

  • Mizuki Shigematsu;Takaaki Udagawa;Satoru Nagase
    • International Journal of High-Rise Buildings
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    • v.12 no.3
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    • pp.215-224
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    • 2023
  • This paper presents the structural design and response control system of the JR MEGURO MARC building, a 70 meters high office building with steel structure located in Tokyo (Figure 1). In order to achieve high earthquake resistance and useable office space, this building integrates a centralized response control system with deformation amplification mechanisms and tuned viscous mass dampers on the lower floor. Moreover, buckling-restrained braces (BRB) are installed on the upper floors to increase the effectiveness of centralized response control system and to reduce damage of the main frames in the event of a major earthquake. It features an efficient centralized response control system by amplifying the deformation of the dampers without creating a soft story.

Mechanisms of herbicide resistance in weeds

  • Bo, Aung Bo;Won, Ok Jae;Sin, Hun Tak;Lee, Jeung Joo;Park, Kee Woong
    • Korean Journal of Agricultural Science
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    • v.44 no.1
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    • pp.1-15
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    • 2017
  • In major field crops, synthetic herbicides have been used to control weeds worldwide. Globally, herbicide resistance in weeds should be minimized because it is a major limiting factor for food security. Cross resistance can occur with herbicides within the same or in different herbicide families and with the same or different sites of action. Multiple resistance refers to evolved mechanisms of resistance to more than one herbicide (e.g., resistance to both ALS-inhibitors and ACCase-inhibitors) and this resistance was brought about by separate selection processes. Target site resistance could occur from changes at the biochemical site of action of one herbicide. Non target site resistance occurs through mechanisms which reduce the number of herbicide molecules that reach the herbicide target site. There are currently 480 unique cases (species ${\times}$ site of action) of herbicide resistance globally in 252 plant species (145 dicots and 105 monocots). To date, resistance in weeds has been reported to 161 different herbicides, involving 23 of the 26 known herbicide sites of action. Finally, it can be concluded that we can protect crops associated to herbicide resistant weeds by applications of biochemical, genetic and crop control strategies.

Regulation of Gene Expression for Amino Acid Biosynthesis in the Yeast, Sacchromyces cerevisiae

  • Lea, Ho Zoo
    • Proceedings of the Zoological Society Korea Conference
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    • 1995.10b
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    • pp.82-82
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    • 1995
  • Regulation of enzyme synthesis by transcriptional and translational control systems provides rather stable adaptation to change of amino acid level in the growth medium, while manipulation of enzyme activity through endproduct feedback inhibition represents rather short-term and reversible ways of adjusting metabolic fluctuation of amino acid level. Various control mechanisms interplay to regulate genes encoding enzymes for amino acid biosynthesis in the yeast, Sacchromyces cerevisiae. When amino acids are in short supply, genes under a cross-pathway regulatory mechanism Or general amino acid control (general control) increase their action, in which Gcn4p is the major positive regulator of gene expression. When cells are cultured in minimal medium, basal level expression is also regulated by supplementary control elements, where inorganic phosphate level is additionally involved. Most of amino acid biosynthetic genes are also regulated by the level of endproduct of the pathway. This pathway-specific regulatory mechanism is called specific amino acid control (specific controD, under which gene expression is reduced when endproduct is present in the medium. Derepression of a gene through general control can be usually overridden by repression through specific control, where the endproduct level of that particular pathway is high and not limiting. In this presentation, regulatory factors for basal level expression and general control of yeast amino acid biosynthesis will be discussed, m addition to pathway-specific repression patterns and interaction between CrOSS- and specific-control mechanisms. Preliminary results are also presented from the investigation of the cloned genes in the threonine biosynthetic pathway of the yeast. yeast.

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A study on new control mechanisms of memory

  • Liu, Haibin;Kakazu, Yukinori
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10b
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    • pp.324-329
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    • 1992
  • A physical phenomenon is observed through analysis of the Hodgkin-Huxley's model that is, according to Maxwell field equations a fired neuron can yield magnetic fields. The magnetic signals are an output of the neuron as some type of information, which may be supposed to be the conscious control information. Therefore, study on neural networks should take the field effect into consideration. Accordingly, a study on the behavior of a unit neuron in the field is made and a new neuron model is proposed. A mathematical Memory-Learning Relation has been derived from these new neuron equations, some concepts of memory and learning are introduced. Two learning theorems are put forward, and the control mechanisms of memory are also discussed. Finally, a theory, i.e. Neural Electromagnetic(NEM) field theory is advanced.

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