• Title/Summary/Keyword: time-critical domains

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Flexible Decision-Making for Autonomous Agent Through Computation of Urgency in Time-Critical Domains (실시간 환경에서 긴급한 정도의 계산을 통한 자율적인 에이전트의 유연한 의사결정)

  • Noh Sanguk
    • Journal of KIISE:Software and Applications
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    • v.31 no.9
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    • pp.1196-1203
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    • 2004
  • Autonomous agents need considerable computational resources to perform rational decision-making. The complexity of decision-making becomes prohibitive when large number of agents are present and when decisions have to be made under time pressure. One of approaches in time-critical domains is to respond to an observed condition with a predefined action. Although such a system may be able to react very quickly to environmental conditions, predefined plans are of less value if a situation changes and re-planning is needed. In this paper we investigate strategies intended to tame the computational burden by using off-line computation in conjunction with on-line reasoning. We use performance profiles computed off-line and the notion of urgency (i.e., the value of time) computed on-line to choose the amount of information to be included during on-line deliberation. This method can adjust to various levels of real-time demands, but incurs some overhead associated with iterative deepening. We test our framework with experiments in a simulated anti-air defense domain. The experiments show that the off-line performance profiles and the on-line computation of urgency are effective in time-critical situations.

MCB ladder diagram modeling for Rolling stock using Petri Net formalism (Petri Net 형식론을 이용한 철도차량 주차단기 제어회로 모델링)

  • Choi, Kwon-Hee;Ahn, Hong-Kwan;Kim, Jae-Gi;Song, Joong-Ho
    • Proceedings of the KSR Conference
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    • 2008.06a
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    • pp.1897-1902
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    • 2008
  • The computer system is used in many application domains and any system error in these domains may either cause critical loss or threaten environment or human life. Though examples of these domains can be found in many areas, the system, which is used in domains for carrying passengers including rolling stocks in particular, is expected to show satisfactory operation all the time. The relay control logic, which is used in rolling stocks, is complex in hardware and occupies considerably large volume. Nevertheless, it has been used for a long time, to let the system safely operate even in the occurrence of an error in the computer system. However, the relay control logic circuit is so complex that the analysis of proper circuit operation and interlocking tends to be dependent only on the designer's experiences instead of being systematically performed. Especially, the analysis following a change, addition and deletion of a previous circuit according to the requirements from a source of demand is significantly limited. In this paper, the accuracy of relay control logic is verified by the use of properties of Petri Net model. In addition, how main circuit breaker (MCB) control circuit is modeled and analyzed by the design methodology is shown.

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Investigation of allowable time-step sizes for generalized finite element analysis of the transient heat equation

  • O'Hara, P.;Duarte, C.A.;Eason, T.
    • Interaction and multiscale mechanics
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    • v.3 no.3
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    • pp.235-255
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    • 2010
  • This paper investigates the heat equation for domains subjected to an internal source with a sharp spatial gradient. The solution is first approximated using linear finite elements, and sufficiently small time-step sizes to yield stable simulations. The main area of interest is then in the ability to approximate the solution using Generalized Finite Elements, and again explore the time-step limitations required for stable simulations. Both high order elements, as well as elements with special enrichments are used to generate solutions. When compared to linear finite elements, the high order elements deliver better accuracy at a given level of mesh refinement, but do not offer an increase in critical time-step size. When special enrichment functions are used, the solution can be approximated accurately on very coarse meshes, while yielding solutions which are both accurate and computationally efficient. The major conclusion of interest is that the significantly larger element size yields larger allowable time-step sizes while still maintaining stability of the time-stepping algorithm.

Pediatric postintensive care syndrome: high burden and a gap in evaluation tools for limited-resource settings

  • Chaiyakulsil, Chanapai;Opasatian, Rapee;Tippayawong, Paweethida
    • Clinical and Experimental Pediatrics
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    • v.64 no.9
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    • pp.436-442
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    • 2021
  • This article aimed to summarize the impact and burden of pediatric postintensive care syndrome (PICS-p) in the physical, mental, cognitive, and social health domains after a review of the current pediatric literature in MEDLINE and PubMed. We also aimed to elucidate the limitations of the current evaluation tools used in limited-resource settings. PICS-p can impact a child's life for decades. Most validated tools are time-consuming, require qualifications, and expertise, are often limited to older children, and can evaluate only one domain. A novel, simple, and comprehensive surveillance tool can aid healthcare providers in the early detection and intervention of PICS-p. Further studies should validate and refine the parameters that will enhance the outcomes of pediatric intensive care unit survivors.

Experimental identification of multiple faults in rotating machines

  • Mahfoud, Jarir;Breneur, Claire
    • Smart Structures and Systems
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    • v.4 no.4
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    • pp.429-438
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    • 2008
  • The aim of this paper is to define the required measurements and processing tools necessary for developing a maintenance approach applied to rotating machines in the presence of multiple faults. The system responses measured were accelerations and transmission errors. Acceleration measurements provide most of the information on bearing conditions, while transmission error measurements provide pertinent information on gear conditions. The measurements were carried out for several operating conditions (loads and speeds). System responses were processed in several analyzing domains (Time, Spectrum, and Cepstrum domains). The approach developed enables the detection and identification of combined faults and it can be applied to other types of rotating machines once the critical elements and their associated faults have been defined.

Microstructure and Trapped Magnetic Field of Multi-Seeded Single Domain YBCO

  • Bierlich, J.;Habisreuther, T.;Litzkendorf, D.;Zeisberger, M.;Gawalek, W.
    • Progress in Superconductivity
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    • v.8 no.1
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    • pp.8-15
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    • 2006
  • The size of the superconducting domains and the critical current density inside these domains have to be enhanced for most of cryomagnetic applications of melt-textured YBCO bulks. To enlarge the size of the domains we studied the multi-seeding technique based on a well-established procedure for preparing high quality YBCO monoliths using self-made SmBCO seeds. The distance between the seeds was optimised as a result of the investigation of the effects of various seed distances on the characteristics of the grain boundary Junctions. The influences of a-b plane intersections and c-axis misalignments were researched. Thereby, a small range of tolerance of the misorientations between the seed crystals was found. Field mapping was applied to control the materials quality and the superconductor's grain structure was investigated using polarisation microscopy. YBCO function elements with iou. seeds in a line and an arrangement of making type (100)/(100) and (110)/(110) boundary junctions, respectively, were processed. The trapped field profile in both sample types shows single domain behaviour. To demonstrate the potential of the multi-seeding method a ring-shaped sample was processed by placing sixteen seeds in a way to make both (100)/(100) and (110)/(110) grain junctions at the same time. The results up to now are very promising to prepare large single domain melt-textured YBCO semi-finished products in complex shapes.

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Comparative Modeling and Molecular Dynamics Simulation of Substrate Binding in Human Fatty Acid Synthase: Enoyl Reductase and β-Ketoacyl Reductase Catalytic Domains

  • John, Arun;Umashankar, Vetrivel;Krishnakumar, Subramanian;Deepa, Perinkulam Ravi
    • Genomics & Informatics
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    • v.13 no.1
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    • pp.15-24
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    • 2015
  • Fatty acid synthase (FASN, EC 2.3.1.85), is a multi-enzyme dimer complex that plays a critical role in lipogenesis. This lipogenic enzyme has gained importance beyond its physiological role due to its implications in several clinical conditions-cancers, obesity, and diabetes. This has made FASN an attractive pharmacological target. Here, we have attempted to predict the theoretical models for the human enoyl reductase (ER) and ${\beta}$-ketoacyl reductase (KR) domains based on the porcine FASN crystal structure, which was the structurally closest template available at the time of this study. Comparative modeling methods were used for studying the structure-function relationships. Different validation studies revealed the predicted structures to be highly plausible. The respective substrates of ER and KR domains-namely, trans-butenoyl and ${\beta}$-ketobutyryl-were computationally docked into active sites using Glide in order to understand the probable binding mode. The molecular dynamics simulations of the apo and holo states of ER and KR showed stable backbone root mean square deviation trajectories with minimal deviation. Ramachandran plot analysis showed 96.0% of residues in the most favorable region for ER and 90.3% for the KR domain, respectively. Thus, the predicted models yielded significant insights into the substrate binding modes of the ER and KR catalytic domains and will aid in identifying novel chemical inhibitors of human FASN that target these domains.

Development of a Critical Pathway for a Korean Medicine Hospital Inpatient with Stroke (중풍 입원 환자 관리를 위한 임상경로 개발)

  • Kim, Mikyung;Han, Chang-ho
    • The Journal of Korean Medicine
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    • v.42 no.2
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    • pp.62-71
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    • 2021
  • Objectives: This study was aimed to share the development process of the critical pathway (CP) for the treatment and management of stroke patients admitted to a Korean medicine hospital. Methods: A draft CP was prepared based on a review of relevant literature and medical records in the hospital, and its validity was reviewed by the in-hospital CP review committee. Each member evaluated all items in the CP on a 5-point Likert scale. Items with an average score of 3.5 or higher or an agreement rate of more than 80% were considered valid. In addition, free described opinions to improve the CP were also received from the review committee. Results: The horizontal axis of the CP was composed of a time domain, including 7 time points from hospitalization to discharge. The vertical axis was composed of 9 domains of medical practice. All items in the CP satisfied the validity criteria. The CP was revised, supplemented, and completed by reflecting the opinions of the committee. Conclusions: This CP will be taught to in-hospital users and will continue to be used with regular monitoring and a feedback plan. This study is expected to serve as a useful reference for standardizing the treatment process and delivering measures to improve the adequacy of Korean medicine treatment for stroke patients.

Measurement and Analysis of the Standard Nursing Practice Times of the ICU Nursing Activities (중환자실 간호행위에 대한 간호소요시간 측정 및 분석)

  • Yoo, Cheong-Suk;Kim, Keum-Soon
    • Journal of Korean Critical Care Nursing
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    • v.2 no.2
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    • pp.56-67
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    • 2009
  • Purpose: This study was done to suggest the standard ICU nursing procedure and standard ICU nursing practice time carried out according to the standard ICU nursing procedure. Methods: Through the literature review, 35 standard ICU nursing activities were selected and classified under 6 categories. Standard nursing procedures were described by research team and 4 clinical practice experts. Content validity of descripted nursing procedure was performed by 6 clinical practice experts. After that standard ICU nursing procedures were identified, standard nursing practice times were checked through 1:1 observation. Results: 35 ICU nursing activities were identified and categorized into 6 domains of activities. Also, their standard nursing procedures were identified, and finally 33 standard nursing practice times were measured and analyzed. The result of the measurement, 1 ICU nursing activity was spent above 30 minutes, 3 activities done within 10-20 minutes, 4 activities done within 5-10 minutes, and 25 activities were spent below 5 minutes. Conclusion: Through this study, 35 standard ICU nursing procedures were described and 33 standard ICU nursing practice times which carried out according to standard ICU nursing procedures were checked. The result can be as fundamental data for the study of nursing activity time in the ICU.

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Advanced Design Environmental With Adaptive And Knowledge-Based Finite Elements

  • Haghighi, Kamyar;Jang, Eun
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 1993.10a
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    • pp.1222-1229
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    • 1993
  • An advanced design environment , which is based on adaptive and knowledge -based finite elements (INTELMESH), has been developed. Unlike other approaches, INTEMMESH incorporates the information about the object geometry as well as the boundary and loading conditions to generate an ${\alpha}$-priori finite element mesh which is more refined around the critical regions of the problem domain. INTEMMESH is designed for planar domains and axisymmetric 3-D structures of elasticity and heat transfer subjected to mechanical and thermal loading . It intelligently identifies the critical regions/points in the problem domain and utilize the new concepts of substructuring and wave propagation to choose the proper mesh size for them. INTEMMESH generates well-shaped triangular elements by applying trangulartion and Laplacian smoothing procedures. The adaptive analysis involves the intial finite elements analyze and an efficient ${\alpha}$-posteriori error analysis involves the initial finite element anal sis and an efficient ${\alpha}$-posteriori error analysis and estimation . Once a problem is defined , the system automatically builds a finite element model and analyzes the problem though automatic iterative process until the error reaches a desired level. It has been shown that the proposed approach which initiates the process with an ${\alpha}$-priori, and near optimum mesh of the object , converges to the desired accuracy in less time and at less cost. Such an advanced design/analysis environment will provide the capability for rapid product development and reducing the design cycle time and cost.

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