• 제목/요약/키워드: Evolutionary Mechanisms

검색결과 64건 처리시간 0.027초

A Conceptual Framework for Value Co-creation in an Innovation Ecosystem: The Case of Technology-based Collaboration Network

  • 한은정;홍순구
    • 한국산업정보학회논문지
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    • 제22권4호
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    • pp.29-43
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    • 2017
  • Innovation Cosystems are Conceptualized as Organizational Networks of Economic Actors, Technologies and Social Contexts that Interact for Knowledge Production, use, and Adaptation. This Paper Proposed a Conceptual Framework to Describe Value Co-creation of Organizational Networks Engaged in Technology Innovation. We Adopted Theory-Based Approach by Integrating the Perspective of Service-Dominant (S-D) Logic Into the Evolutionary Model of the Triple Helix. The Framework Gives a Plausible Explanation on how Actors Collaborate to Create Value in Dynamic Contexts of an Innovation Ecosystem. The Innovation Ecosystem can be Considered as a Composite of Sub-Ecosystems, Including Knowledge, Sectoral, and Business Ecosystems. When these Sub-Ecosystems are Recursively Transformed by Coordination of Functional Mechanisms that Serve Value Co-creation in the Innovation Process, the Innovation Ecosystem will be Re-Organized and Evolve. The case of the Digital Living Network Alliance (DLNA) was Examined to Demonstrate the Fundamental Mechanisms for Value Co-creation that was Described in the Framework. The case Study Indicates Features of Value Co-creation when Implementing Innovation in Organizational Networks.

미소유동 채널에서 중첩된 전기이중층 구조의 과도 형성과정 (Transient Evolution of Overlapped EDL Fields in a Microfluidic Channel)

  • 곽호상
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 추계학술대회
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    • pp.1528-1533
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    • 2004
  • A numerical investigation is made of transient evolutionary prcocess of electroosmotic flow in a two-dimensional microchannel connected to a reservoir. The channel height is very small so that two electric double layers forming on the charged surfaces are overlapped. Transient transports of ions in the electrolyte solution are computed by integrating the Nernst-Planck equation together with the Poisson equation for electric potential. The numerical results illustrate that there are two distinct transient phases. The physical mechanisms and relevant time scales for the transient evolution are described.

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1978年度 秋季硏究發表論文 要旨錄: 1. Recent Advances in the Study of Oogenesis

  • King, Robert C.
    • 한국동물학회지
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    • 제22권1호
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    • pp.26-38
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    • 1979
  • In recent years some very substantial advances have been made in our understanding of oogenesis as a result of studies on a relatively few, very diverse species of animals. In this lecture I will (1) outline normal oogenesis using an advanced insect, Drosophila melanogaster, as an example, (2) show how oogenesis can be dissected genetically by studying the ovarian pathologies of flies homozygous for various recessive, female sterile genes, and (3) discuss how estimates can be made of the fraction of the Drosophila genome devoted to oogenesis. Then I will describe studies on mutations that block vitello-genesis in Drosophila and indicate what they tell us about inter actions between the ovary, the fat body and the endocrine system. I will next discuss the evolutionary mechanisms that have been adopted in higher insects and amphibians to produce the prodigious quantities of ribosomes stored in oocytes. I will end with an account of the results of recent stuides on amphibian lampbrush chromosomes which show how messenger RNAs are transcribed during oogenesis.

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Molecular Co-evolution of Gonadotropin-releasing Hormones and Their Receptors

  • Seong, Jae-Young;Kwon, Hyuk-Bang
    • Animal cells and systems
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    • 제11권2호
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    • pp.93-98
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    • 2007
  • Gonadotropin-releasing hormone (GnRH), synthesized in the hypothalamus, plays a pivotal role in the regulation of vertebrate reproduction. Since molecular isoforms of GnRH and their receptors (GnRHR) have been isolated in a broad range of vertebrate species, GnRH and GnRHR provide an excellent model for understanding the molecular co-evolution of a peptide ligand-receptor pair. Vertebrate species possess multiple forms of GnRH, which have been created through evolutionary mechanisms such as gene/chromosome duplication, gene deletion and modification. Similar to GnRHs, GnRH receptors (GnRHR) have also been diversified evolutionarily. Comparative ligand-receptor interaction studies for non-mammalian and mammalian GnRHRs combined with mutational mapping studies of GnRHRs have aided the identification of domains or motifs responsible for ligand binding and receptor activation. Here we discuss the molecular basis of GnRH-GnRHR co-evolution, particularly the structure-function relationship regarding ligand selectivity and signal transduction of mammalian and non-mammalian GnRHRs.

개선된 미분 진화 알고리즘에 의한 퍼지 모델의 설계 (Design of Fuzzy Models with the Aid of an Improved Differential Evolution)

  • 김현기;오성권
    • 한국지능시스템학회논문지
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    • 제22권4호
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    • pp.399-404
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    • 2012
  • Evolutionary algorithms such as genetic algorithm (GA) have been proven their effectiveness when applying to the design of fuzzy models. However, it tends to suffer from computationally expensWive due to the slow convergence speed. In this study, we propose an approach to develop fuzzy models by means of an improved differential evolution (IDE) to overcome this limitation. The improved differential evolution (IDE) is realized by means of an orthogonal approach and differential evolution. With the invoking orthogonal method, the IDE can search the solution space more efficiently. In the design of fuzzy models, we concern two mechanisms, namely structure identification and parameter estimation. The structure identification is supported by the IDE and C-Means while the parameter estimation is realized via IDE and a standard least square error method. Experimental studies demonstrate that the proposed model leads to improved performance. The proposed model is also contrasted with the quality of some fuzzy models already reported in the literature.

선형전동기 기반 컨테이너 이송 시스템의 정밀 위치제어 (Precision Position Controller of Linear Motor-Based Container Transfer System)

  • 이영진;이진우;조현철;이권순
    • 전기학회논문지P
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    • 제57권3호
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    • pp.215-224
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    • 2008
  • In this paper, we introduced a linear motor-based transfer system with an active pid controller which can be replaced with an automated guided vehicle (AGV) for the port automation. This system, which is named LMCTS(liner motor-based container transfer system), is based on PMLSM (permanent magnetic linear synchronous motor) which basically consists of stator modules on the rail and shuttle car. Therefore more progressive and adaptive control mechanisms should be required to control a system with large variation of container weight, the difference of each characteristic of stator modules, a stator module's trouble etc. We introduced an active control mechanism with an online tuning scheme using modified evolutionary strategy. Some computer simulations are implemented to assess the robustness of the proposed system.

Loss of gene function and evolution of human phenotypes

  • Oh, Hye Ji;Choi, Dongjin;Goh, Chul Jun;Hahn, Yoonsoo
    • BMB Reports
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    • 제48권7호
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    • pp.373-379
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    • 2015
  • Humans have acquired many distinct evolutionary traits after the human-chimpanzee divergence. These phenotypes have resulted from genetic changes that occurred in the human genome and were retained by natural selection. Comparative primate genome analyses reveal that loss-of-function mutations are common in the human genome. Some of these gene inactivation events were revealed to be associated with the emergence of advantageous phenotypes and were therefore positively selected and fixed in modern humans (the "less-ismore" hypothesis). Representative cases of human gene inactivation and their functional implications are presented in this review. Functional studies of additional inactive genes will provide insight into the molecular mechanisms underlying acquisition of various human-specific traits. [BMB Reports 2015; 48(7): 373-379]

컨텐츠 지향적 하이퍼미디어 설계 방법론 (A Methodology for Designing Contents-Oriented Hypermedia)

  • 서우종;이희석
    • Asia pacific journal of information systems
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    • 제10권1호
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    • pp.81-106
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    • 2000
  • Recently there have been many efforts to develop hypermedia systems. Hypermedia applications can be categorized into process-oriented or contents-oriented. However, it is not a trivial task to build contents-oriented hypermedia in a systematic fashion. The contents-oriented hypermedia systems are developed primarily for the applications of marketing or information services. This paper proposes a methodology for a contents-oriented hypermedia system. Hypermedia contents are typically structured in the form of hierarchies. An index node can be used in order to give an effective access to this hierarchical structure. The proposed methodology employs three types of nodes(contents, index and function) and various navigation mechanisms, and helps design contents-oriented hypermedia systematically. Furthermore, various design techniques are proposed for maintaining contents-oriented hypermedia systems that have an evolutionary feature. Two real-life cases are illustrated to demonstrate the applicability of the methodology.

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Genetic Linkage Plays an Important Role in Maintaining Genetic Variability under Stabilizing Selection in Changing Environment

  • Jeung, Min-Gull;Janes N. Thompson, Jr;Lee, Chung-Choo
    • Animal cells and systems
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    • 제1권4호
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    • pp.619-627
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    • 1997
  • Maintenance of polymorphism in a two-locus system with two alleles under stabilizing selection has been tested by Monte-Carlo simulation. The effect of each allele was additive. Only gene x environment interactions and degree of genetic linkage between loci were considered. There were no other evolutionary forces acting except stabilizing selection. Fixation rates were influenced by the extent of environmental change and the degree of genetic linkage. In most cases, stabilizing selection depleted genetic variability when two loci have a lower degree of linkage (10 cM). When two loci are closely linked (0.1 cM), however, stabilizing selection promoted balanced heterozygotes in changing environments. Thus, environment-dependent selection and recombination rate are important parameters which should be incorporated into mechanisms of maintenance of genetic variability.

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Evolution of avian infectious bronchitis virus: Genetic drift and recombination

  • Lee, Chang-Won
    • 한국동물위생학회지
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    • 제25권1호
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    • pp.97-103
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    • 2002
  • Infectious bronchitis(IB) is a viral disease in which continued evolution of the virus is of paramount importance for annual endemics and epidemics in chickens. Since the isolation of IB viruses(IBVs) in the 1930s, over 50 serotypes or variants have been reported worldwide. Continuing evolution is most prominent in the suface glycoproteins of IBV but also occurs in other parts of the genome. This genetic variability results from accumulation of molecular changes that can occur by a number of different mechanisms including genetic drift (point mutations) and genetic shift(RNA recombination). GA98 is a new serotype of IBV identified recently in the United States. In this paper, the evolutionary trend of IBV will be discussed using GA98 serotype as a model.