• 제목/요약/키워드: Evolutionary trends

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경관평가연구의 국내외 동향 (Domestic and Foreign Trends in the Study of the Landscape Evaluation)

  • 주신하;임승빈
    • 한국조경학회지
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    • 제28권2호
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    • pp.49-60
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    • 2000
  • The purpose of this study is to overview domestic and foreign trends in the study of the landscape evaluation through new framework of landscape evaluation studies. 108 studies on the landscape evaluation are summarized and categorized into theoretical studies, verification of theories, development of evaluation methods and applications in physical planning. Major theories in the landscape evaluation came from the psycho-physics, the evolutionary theory ann the cultural-learning theory, and were verified and applied into physical planning. Early experimental researches on landscape evaluation, based on psycho-physics, were focused on relatively simple responses to landscapes. But many studies have been gradually related to the evolutionary theory and the cultural learning theory, emphasizing biological and cultural effects on landscape evaluation. Especially, Appleton's Prospect-Refuge theory' and Kaplans' 'Information Processing model' have very strong influence in landscape evaluation. Relatively there have been many application researches in Korea, which tells there have been strong needs to solve pending practical problems caused by the rapid economic and social growth for several decades. Almost of applications in physical planning are focused on physical features of landscapes, but for more comprehensive landscape evaluation, many other factors such as cognitive and sociocultural variables should be integrated into the whole evaluation system. As a result of reviewing of landscape evaluation studies, I found the overall domestic and foreign trends and the necessity of more research on the applications in physical planning. Because this study mainly focused on academic researches, for more appropriate landscape evaluation and management there should be more practical researches including various approaches.

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Morphological Characteristics and Phylogenetic Trends of Trematode Cercariae in Freshwater Snails from Nakhon Nayok Province, Thailand

  • Chontananarth, Thapana;Tejangkura, Thanawan;Wetchasart, Napat;Chimburut, Cherdchay
    • Parasites, Hosts and Diseases
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    • 제55권1호
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    • pp.47-54
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    • 2017
  • The prevalence of cercarial infection in freshwater snails and their evolutionary trends were studied in Nakhon Nayok province, Thailand. A total of 2,869 individual snails were examined for parasitic infections. The results showed that 12 snail species were found to host larval stages of trematodes with an overall prevalence of 4.7%. The infected specimens included 7 types at the cercarial stage; cercariae, megalurous cercariae, echinostome cercariae, furcocercous cercariae, parapleurolophocercous cercariae, virgulate cercariae, and xiphidiocercariae. Regarding molecular identification, ITS2 sequence data of each larval trematode were analyzed, and a dendrogram was constructed using the neighbor-joining method with 10,000 replicates. The dendrogram was separated into 6 clades (order/family), including Echinostomatida/Echinostomatidae, Echinostomatida/Philophthalmidae, Opisthorchiida/Heterophyidae, Plagiorchiida/Prosthogonimidae, Plagiorchiida/Lecithodendriidae, and Strigeatida/Cyathocotylidae. These findings were used to confirm morphological characteristics and evolutionary trends of each type of cercariae discovered in Nakhon Nayok province. Furthermore, this investigation confirmed that the ITS2 data of cercariae could be used to study on phylogenetic relationships or to determine classification of this species at order and/or family level when possible.

국방연구개발의 진화적 획득전략 적용방안 (The Applications of an Evolutionary Acquisition Strategy to Defense R&D Programs)

  • 정청진;권용수
    • 시스템엔지니어링학술지
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    • 제3권1호
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    • pp.9-15
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    • 2007
  • An EA(Evolutionary Acquisition) strategy is based on the systems engineering. It is a preferred approach to provide operationally useful capabilities to the warfighter much more quickly than single-step to full capability strategy. Recently, DoD is trying to apply the acquisition process based on the systems engineering. In spite of these trends, efforts of domestic defense acquisition society to this strategy are insufficient. Although an EA strategy has many benefits, there are many constraints to apply it. This study analyzes these constraints and presents applications of the EA strategy to defense R&D programs.

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Multi-objective Optimization of a Laidback Fan Shaped Film-Cooling Hole Using Evolutionary Algorithm

  • Lee, Ki-Don;Husain, Afzal;Kim, Kwang-Yong
    • International Journal of Fluid Machinery and Systems
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    • 제3권2호
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    • pp.150-159
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    • 2010
  • Laidback fan shaped film-cooling hole is formulated numerically and optimized with the help of three-dimensional numerical analysis, surrogate methods, and the multi-objective evolutionary algorithm. As Pareto optimal front produces a set of optimal solutions, the trends of objective functions with design variables are predicted by hybrid multi-objective evolutionary algorithm. The problem is defined by four geometric design variables, the injection angle of the hole, the lateral expansion angle of the diffuser, the forward expansion angle of the hole, and the ratio of the length to the diameter of the hole, to maximize the film-cooling effectiveness compromising with the aerodynamic loss. The objective function values are numerically evaluated through Reynolds- averaged Navier-Stokes analysis at the designs that are selected through the Latin hypercube sampling method. Using these numerical simulation results, the Response Surface Approximation model are constructed for each objective function and a hybrid multi-objective evolutionary algorithm is applied to obtain the Pareto optimal front. The clustered points from Pareto optimal front were evaluated by flow analysis. These designs give enhanced objective function values in comparison with the experimental designs.

Trends in Satellite Communication Technology

  • 고의곤
    • 전기의세계
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    • 제39권5호
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    • pp.27-37
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    • 1990
  • In this paper some of the important trends in the spacecraft technology development have been discussed. Trends of higher satellite radiate power, which involves higher TWTA powers and antenna reconfiguration, and Ka-band (30/20 G $H_{z}$) utilization are discussed. Evolutionary trends in satellite communications in general have demonstrated immense potential for meeting the evolving nees and challenges regarding provision of global telecommunications during over past two decades. Their promise for the coming decades as we enter the 21st century may far surpass our imagination. The expansion of fixed satellite service market will depend upon more inelligent spacecraft and a network of more cost effective small earth stations. Radiation hardened microwave analog technologies and high speed digital technologies are getting ready to meet the challenge posed by future markets. At present commercial satellite communications are going through a trasition period.d.

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양자 기술 구현을 위한 칩 제작 인프라 기술 동향 (Trends in Chip Fabrication Infrastructure for Implementation in Quantum Technology)

  • 김진우;문기원;주정진
    • 전자통신동향분석
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    • 제38권1호
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    • pp.9-16
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    • 2023
  • In the rapidly growing field of quantum computing, it is evident that a robust supply chain is needed for commercialization or large-scale production of quantum chips. As a result, the success of many R&D projects worldwide relies on the development of quantum chip foundries. In this paper, a variety of quantum chip foundries, particularly the ones creating photonic integrated circuit (PIC) quantum chips, are reviewed and summarized to demonstrate current technological trends. Global projects aiming to establish new foundries, as well as information regarding their respective funding, are also included to identify the evolutionary direction of quantum computing infrastructure. Furthermore, the potential application of lithium niobate as a novel material platform for quantum chips is also discussed.

Wood Anatomy and Phylogeny of Laurus ( Lauraceae )

  • Heo, Kweon
    • Plant Resources
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    • 제1권2호
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    • pp.121-125
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    • 1998
  • Wood and bark structure of Laurus, which is considered as an important spice resources was characterized by several transitional and advanced features. Annual rings are distinct: vessel elements are moderately short and narrow, both simple and sealariform perforation plates. alternate intervascular pitting; irregularly septate fiber are present; parenchyma strands are scanty paratracheal: rays are both homogeneous and heterogeneous with multiseriate: phloem rays are dilated. Comparisons with other genera of Lauraceae suggest that Laurus is transitional and advanced state in evolutionary trends in the family.

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자동 기계학습(AutoML) 기술 동향 (Recent Research & Development Trends in Automated Machine Learning)

  • 문용혁;신익희;이용주;민옥기
    • 전자통신동향분석
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    • 제34권4호
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    • pp.32-42
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    • 2019
  • The performance of machine learning algorithms significantly depends on how a configuration of hyperparameters is identified and how a neural network architecture is designed. However, this requires expert knowledge of relevant task domains and a prohibitive computation time. To optimize these two processes using minimal effort, many studies have investigated automated machine learning in recent years. This paper reviews the conventional random, grid, and Bayesian methods for hyperparameter optimization (HPO) and addresses its recent approaches, which speeds up the identification of the best set of hyperparameters. We further investigate existing neural architecture search (NAS) techniques based on evolutionary algorithms, reinforcement learning, and gradient derivatives and analyze their theoretical characteristics and performance results. Moreover, future research directions and challenges in HPO and NAS are described.

기계학습기반 초신뢰·저지연 무선통신기술 연구동향 (Research Trends of Ultra-reliable and Low-latency Machine Learning-based Wireless Communication Technology)

  • 이현;권동승
    • 전자통신동향분석
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    • 제34권3호
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    • pp.93-105
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    • 2019
  • This study emphasizes the importance of the newly added Ultra-Reliable and Low-Latency Communications (URLLC) service as an important evolutionary step for 5G mobile communication, and proposes a remedial application. We analyze the requirements for the application of 5G mobile communication technology in high-precision vertical industries and applications, introduce the 5G URLLC design principles and standards of 3GPP, and summarize the current state of applied artificial intelligence technology in wireless communication. Additionally, we summarize the current state of research on ultra-reliable and low-latency machine learning-based wireless communication technology for application in ultra-high-precision vertical industries and applications. Furthermore, we discuss the technological direction of artificial intelligence technology for URLLC wireless communication.