• Title/Summary/Keyword: unit coordination

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Blood-neural barrier: its diversity and coordinated cell-to-cell communication

  • Choi, Yoon-Kyung;Kim, Kyu-Won
    • BMB Reports
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    • v.41 no.5
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    • pp.345-352
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    • 2008
  • The cerebral microvessels possess barrier characteristics which are tightly sealed excluding many toxic substances and protecting neural tissues. The specialized blood-neural barriers as well as the cerebral microvascular barrier are recognized in the retina, inner ear, spinal cord, and cerebrospinal fluid. Microvascular endothelial cells in the brain closely interact with other components such as astrocytes, pericytes, perivascular microglia and neurons to form functional 'neurovascular unit'. Communication between endothelial cells and other surrounding cells enhances the barrier functions, consequently resulting in maintenance and elaboration of proper brain homeostasis. Furthermore, the disruption of the neurovascular unit is closely involved in cerebrovascular disorders. In this review, we focus on the location and function of these various blood-neural barriers, and the importance of the cell-to-cell communication for development and maintenance of the barrier integrity at the neurovascular unit. We also demonstrate the close relation between the alteration of the blood-neural barriers and cerebrovascular disorders.

A Study on Introducing Fractions in Mathematics Textbooks: Focused on Stages of Units Coordination (초등학교 수학 교과서의 분수 도입 방법에 대한 고찰: 단위 조정 단계를 중심으로)

  • Lee, Jiyoung
    • Journal of Elementary Mathematics Education in Korea
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    • v.23 no.3
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    • pp.323-345
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    • 2019
  • This study examines the introduction of fractions in the third grade mathematics textbooks focusing on stages of units coordination and suggests alternative activities to help students develop their understanding of fractions. As results, the sessions of introduction units in textbooks was well organized to allow students to construct more extensive fraction schemes (i.e., Part-whole fraction scheme → Partitive unit fraction scheme → Partitive fraction scheme). However, most of the activities in textbooks were related to stages 1 and 2 of units coordination. In particular, the operations and partitioning schemes (i.e., equi-partitioning and splitting schemes), which are key to the development of students' fraction knowledge, were not explicitly revealed. Fraction schemes also did not extend to the Iterative fraction scheme, which is central to the construction of improper fractions. Based on these results, this study is expected to provide implications for the introduction of fractions in textbooks focusing on stages of units coordination to teachers and textbook developers.

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A Study on the Network of Civilian, Enterprise, School and Government Sectors for Disaster Management (재난관리를 위한 민관산학네트워크 구축에 관한 연구)

  • Sung, Ki-Whan
    • Journal of the Korean Society of Safety
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    • v.20 no.4 s.72
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    • pp.154-161
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    • 2005
  • As disasters in the modem era become a large scale and complexity, no single entity can manage them. Instead collective cooperation between civilian, enterprise, school and government sectors is significantly needed, along with a well prepared mechanism. Thus, I attempt to construct the applicable network of civilian, enterprise, school and government sectors for disaster management through exemplary case studies of established countries as well as Korea's current operations and its drawbacks, based upon a networking design of disaster management organizations as belows: Firstly, it is cooperation and coordination among relevant organizations that are required essentially in the new era, in view of formative condition of necessary environment for civil participation. The cooperation and coordination can be made only through the network of civilian, enterprise, school and government sectors. Secondly, in order to build up the network, major roles and tasks which should be done by civilian, enterprise, school and government sectors respectively are listed based upon a stage of disaster management. Thirdly, operation models of a safety monitoring unit, a disaster prevention unit, a emergency response unit, and a rehabilitation unit are proposed in line with the network of civilian, enterprise, school and government sectors in regional base.

A Fourth Grade Student's Units Coordination for Fractions (단위 조정에 따른 초등학생의 분수 개념 이해 분석)

  • Yoo, Jinyoung;Shin, Jaehong
    • Education of Primary School Mathematics
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    • v.23 no.2
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    • pp.87-116
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    • 2020
  • The purpose of this study is to explore how units-coordination ability is related to understanding fraction concepts. For this purpose, a teaching experiment was conducted with one fourth grade student, Eunseo for four months(2019.3. ~ 2019.6.). We analyzed in details how Eunseo's units-coordinating operations related to her understanding of fraction changed during the teaching experiment. At an early stage, Eunseo with a partitive fraction scheme recognized fractions as another kind of natural numbers by manipulating fractions within a two-levels-of-units structure. As she simultaneously recognized proper fraction and a referent whole unit as a multiple of the unit fraction, she became to distinguish fractions from natural numbers in manipulating proper fractions. Eunseo with a reversible partitive fraction scheme constructed a natural number greater than 1, as having an interiorized three-levels-of-units structure and established an improper fraction with three levels of units in activity. Based on the results of this study, conclusions and pedagogical implications were presented.

A Study on the Effective Coordination Scheme of Recloser for the Conventional Distribution System Interconnected Dispersed Generation (배전계통에 분산전원 연계시 기존 배전 계통측의 효과적인 리클로저 보호협조 연구)

  • Jung, Seung-Bock;Kim, Jae-Chul;Moon, Jong-Fil;Yun, Sang-Yun;Choi, Joon-Ho;Bae, Joo-Chun
    • Proceedings of the KIEE Conference
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    • 2002.07a
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    • pp.533-535
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    • 2002
  • In Korea, power requirement has been increasing. But the large generation unit is hardly installed because of economic and environment problem. Therefore, the concern of dispersed generation system(DGS) is growing. The power distribution system is generally operated with radial type. The protection system is composed of one directive source. But power distribution system inserted DGS changes it to two directive source system. Therefore, the insertion of DGS has the problem of protection coordination. In this paper, we argue fault current affected by interconnected DGS. We analyze fault current flow affected by DGS placement. Then, we find protective coordination problem. Consequently, we study advance point for protection scheme of power system interconnected DGS.

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Synthesis, Crystal Structure and Characterization of Cu(II) and Cd(II) Coordination Compounds Based on Ligand 2-(3-(Pyridin-2-yl)-1H-pyrazol-1-yl)acetic Acid

  • Zhang, Ya-Jun;Wang, Cui-Juan;Mao, Kai-Li;Liu, Xiao-Lei;Huang, Shuai;Tong, Yan;Zhou, Xian-Li
    • Bulletin of the Korean Chemical Society
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    • v.35 no.7
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    • pp.2086-2092
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    • 2014
  • Two novel coordination compounds $[Cu_2(pypya)_3(H_2O)_2]{\cdot}Cl{\cdot}(H_2O)_5$ (1) and $\{[Cd(pypya)(ta)_{1/2}]{\cdot}H_2O\}_n$ (2) (Hpypya=2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl)acetic acid, $H_2ta$=terephthalic acid) were synthesized and characterized by single X-ray diffraction. Structure determination reveals that complex 1 and complex 2 crystallize in the triclinic system, with the P-1 space group. The asymmetric unit of 1 contains two Cu(II) ions, and their coordination modes are different. These units of complex 1 are linked together via hydrogen bonds and ${\pi}-{\pi}$ interactions, and the 3D structure of complex 1 was formed. Complex 2, a mononuclear Cd(II) coordination compound, has a 2D structure which was constructed via coordination bonds. TGA and fluorescence spectra analysis of complex 1 and complex 2 have also been studied. In addition, the geometry parameters of complex 1 have been optimized with the B3LYP method of density functional theory (DFT) to explain its coordination behavior. The electronic properties of the complex 1 and ligand Hpypya have been investigated based on the nature bond orbital (NBO) analysis at the B3LYP level of theory. The result verifies that the synergistic effect have occurred in the compound.

An Analysis on Preference of Interior Coordination Elements for Urban Small Housing - Focused on Gold-Generation(Gold Miss, Gold Mr.) - (도시형 소형주택의 실내코디네이션 요소 선호 분석 - 골드세대(골드미스, 골드미스터) 수요자를 중심으로 -)

  • Kim, So-Hee;Han, Young-Ho
    • Korean Institute of Interior Design Journal
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    • v.21 no.5
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    • pp.264-271
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    • 2012
  • As changed population structure variously, population decrease is one of the important problem in present urbanization. It resulted decline of the medium-large size housings that increasing of 1-2 person household need the variety of small housing with housing type. This study was researched the Gold-Generation on theme by Gold Miss, Gold Mr. who preferring urban small housings that it analyzed survey of Gold generation who be wanted urban small housing by interior coordination elements. Data to be analyzed that first, Gold Mr. and Miss are preferred two bedroom applied by spatial structure coordination. Especially it is based on the separation between livingroom and bedroom with duplex type which is bathroom formed single unit type(shower/toilet/basin). In interior coordination of spatial elements, Gold Mr. considered the form of kitchen with huge ㄷ type instead of Gold Miss are preferred alpha room or alpha space to use powder room or dress room. Second, In Preference of interior coordination elements, Gold Mr. and Miss are preferred bed-clothes and curtains by fabrics, lighting are hanging and spot lighting, accessories are carpet with rug and porcelains. Color are preferred bright scheme both white and ivory, however preference of furniture is different from Gold Mr. and Gold Miss that Gold Mr. are ordered desk, sofa and shelves but Gold Miss are preferred sofa, bed, and dressing table. It showed between Gold Mr. and Gold Miss are equal needs or differences. It expects the basic research for understanding the interior coordination elements for preference in urban small housing as focused on Gold generation(Gold Miss, Gold Mr.) that they will be applied the interior space on urban small housing.

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Collaborative Work Applications Development Environment based on Hierarchical Coordination Model using Mobile Agent (이동 에이전트를 이용한 계층적 조정 모델 기반 협력 작업 응용 개발 환경)

  • Kim Young-Min;Lee Sang-Ho
    • Journal of the Korea Society of Computer and Information
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    • v.11 no.2 s.40
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    • pp.285-294
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    • 2006
  • The requirements of Computer Supported Cooperative Work supporting efficient cooperative or collaborative works between multi-users have been increasing in distributed environments. The various technical sections such as group communication technology and distributed processing technology should be provided in Cooperative Work. The replicated development of Cooperative Work applications of a number of common requirements increases development costs enormously and duplicated investment parts. Therefore, systematical development environments are required to develop these common requirements and applications efficiently in Cooperative Work applications development. In this study, we propose the hierarchical role-based coordination model that improves the coordination model of legacy mobile agent to be appropriate in Cooperative Work applications, and design the development environment for Cooperative Work applications based on mobile agent. The proposed hierarchical role-based coordination model provides multi-layered group concepts of mobile agent, and enables implementation of efficient coordination policy per group. Additionally, it supports efficient Cooperative Work application development by role assignment per group unit.

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A study on Protective Coordination of MCA for Performing of the Pad Mounted Transformer's inside Protective Device (지상변압기의 내부 보호장비 작동을 위한 MCA 보호협조에 대한 연구)

  • Hyun, Seung-Yoon;Kim, Chang-Hwan
    • KEPCO Journal on Electric Power and Energy
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    • v.8 no.1
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    • pp.5-7
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    • 2022
  • KEPCO's plan is undergoing a trial operation to replace the open-loop section with ring main units configuration where underground distribution lines are installed, by linking the multi-way circuit breakers auto (MCA) on the power side of each pad-mounted transformer. However, ring main units application mentioned above may cause the ripple effects, when implementing the configuration without a study of protection coordination. Because ring main units with classical pre-set protection devices contribution in fault condition didn't consider yet. For the reliable ring main units operation, it is necessary to resolve several protection issues such as the protection coordination with substation side, prevention of the transformer inrush current. These issues can radically deteriorate the distribution system reliability Hence, it is essential to design proper protection coordination to reduce these types of problems. This paper presents a scheme of ring main units' configuration and MCA's settings of time-current curves to preserve the performance of protection coordination among the switchgears considering constraints, e.g. prevention of the ripple effects (on the branch section when a transformer failure occurs and the mainline when a branch line failure occurs). It was confirmed that the propagation of the failure for each interrupter segment could be minimized by applying the proposed TCC and the interrupter settings for the MCAs (branch, transformer). Further, it was verified that the undetected area of the distribution automation system (DAS) could be supplemented by having the MCA configurated ring main units operate first, instead of the internal protection equipment in the transformer such as the fuse, STP when a transformer failure occurs.