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      • KCI등재후보

        '기술-쓰레기'의 계보

        이정현 한국문화연구학회 2023 문화연구 Vol.11 No.2

        At the most final stage of the life cycle of a product, when it can no longer be used or is unusable, we call it "waste." Waste has largely been a matter of indifference, while we describe and experience the technology as progress. However, the question of what to classify as waste, where to dispose of this waste, and who will move this waste has historically involved social context and contemporary power. This article defines waste generated as an inevitable byproduct of technological development as "tech-waste" and explores the genealogical composition of tech-waste within Korean society. This paper describes how technological waste has been defined and managed in Korea, focusing on the discourse found in KBS news reports searched for using "waste" as a keyword from 1987 to 2023 and policy reports from the Ministry of Environment's digital library during the same period. It categorizes technological waste into the emergence of technological waste, its authoritative (re)placement, and ubiquitous technological waste. Through this process, this paper aims to allow a critical understanding of tech-waste, which invisible mediates human-technology-environment, and reflect on the organic relationship between them.

      • KCI등재

        Genetic algorithm–based scheduling for ground support of multiple satellites and antennae considering operation modes

        이정현,김해동,정현,고광희 한국항공우주학회 2016 International Journal of Aeronautical and Space Sc Vol.17 No.1

        Given the unpredictability of the space environment, satellite communications are manually performed by exchanging telecommands and telemetry. Ground support for orbiting satellites is given only during limited periods of ground antenna visibility, which can result in conflicts when multiple satellites are present. This problem can be regarded as a scheduling problem of allocating antenna support (task) to limited visibility (resource). To mitigate unforeseen errors and costs associated with manual scheduling and mission planning, we propose a novel method based on a genetic algorithm to solve the ground support problem of multiple satellites and antennae with visibility conflicts. Numerous scheduling parameters, including user priority, emergency, profit, contact interval, support time, remaining resource, are considered to provide maximum benefit to users and real applications. The modeling and formulae are developed in accordance with the characteristics of satellite communication. To validate the proposed algorithm, 20 satellites and 3 ground antennae in the Korean peninsula are assumed and modeled using the satellite tool kit (STK). The proposed algorithm is applied to two operation modes: (i) telemetry, tracking, and command and (ii) payload. The results of the present study show near-optimal scheduling in both operation modes and demonstrate the applicability of the proposed algorithm to actual mission control systems.

      • KCI등재

        On-Board Orbit Propagator and Orbit Data Compression for Lunar Explorer using B-spline

        이정현,최수진,고광희 한국항공우주학회 2016 International Journal of Aeronautical and Space Sc Vol.17 No.2

        In this paper, an on-board orbit propagator and compressing trajectory method based on B-spline for a lunar explorer are proposed. An explorer should recognize its own orbit for a successful mission operation. Generally, orbit determination is periodically performed at the ground station, and the computed orbit information is subsequently uploaded to the explorer, which would generate a heavy workload for the ground station and the explorer. A high-performance computer at the ground station is employed to determine the orbit required for the explorer in the parking orbit of Earth. The method not only reduces the workload of the ground station and the explorer, but also increases the orbital prediction accuracy. Then, the data was compressed into coefficients within a given tolerance using B-spline. The compressed data is then transmitted to the explorer efficiently. The data compression is maximized using the proposed methods. The methods are compared with a fifth order polynomial regression method. The results show that the proposed method has the potential for expansion to various deep space probes.

      • KCI등재

        Schedule Optimization of Imaging Missions for Multiple Satellites and Ground Stations Using Genetic Algorithm

        이정현,김희원,정현,김해동,최수진,정옥철,정대원,고광희 한국항공우주학회 2018 International Journal of Aeronautical and Space Sc Vol.19 No.1

        In this paper, we propose a method that uses a genetic algorithm for the dynamic schedule optimization of imaging missions for multiple satellites and ground systems. In particular, the visibility conflicts of communication and mission operation using satellite resources (electric power and onboard memory) are integrated in sequence. Resource consumption and restoration are considered in the optimization process. Image acquisition is an essential part of satellite missions and is performed via a series of subtasks such as command uplink, image capturing, image storing, and image downlink. An objective function for optimization is designed to maximize the usability by considering the following components: user-assigned priority, resource consumption, and image-acquisition time. For the simulation, a series of hypothetical imaging missions are allocated to a multi- satellite control system comprising five satellites and three ground stations having S- and X-band antennas. To demonstrate the performance of the proposed method, simulations are performed via three operation modes: general, commercial, and tactical.

      • KCI등재

        가상인간을 생산하는 몸, 노동, 미디어 가상인간 ‘로지’ 사례를 중심으로

        이정현 한국언론학회 2023 커뮤니케이션 이론 Vol.19 No.3

        As the technology for producing cultural and media content diversifies, the emergence of "virtual humans" is reshaping the conventions and landscapes of cultural industries. Criticizing the limitation of the social discourse and academic discussions surrounding virtual humans, which have focused primarily on their economic effects and industrial value as media commodities, this study argues for the necessity of research into the "production" and "production system" of virtual humans as a new media cultural phenomenon. When considering the media ecosystem that is being reconfigured around digital computers and artificial intelligence, this study theoretically describes the need to investigate the multi-layered production system, including producers, technology, and production networks, which are complexly involved in "production" within the contemporary media environment. Then, the study summarizes the system producing the virtual human "Rozy" into four contexts: 1) the production network of algorithms, graphics, and digital technologies, 2) repetitive labor in tech-professionals, 3) social media and digital care-giving labor, and 4) the labor of faceless bodies as ghost labor. Through the case of producing the virtual human "Rozy," the study captures a facet of the dynamic changes that the cultural industry is undergoing due to the evolving technologies contributing to production and distribution. Furthermore, it highlights new perspectives and critical viewpoints for media production studies within the changing media ecosystem.

      • KCI등재

        Preliminary search of intraspecific chloroplast DNA variation of nine evergreen broad leaved plants in East Asia

        이정현,최병희,이병윤 한국식물분류학회 2011 식물 분류학회지 Vol.41 No.3

        In order to acquire information on chloroplast DNA markers to evaluate the genetic diversity of evergreen broad leaved plants, we investigated the intraspecific variation of cpDNA in eight non-coding regions of nine species commonly distributed in East Asia. Although no variations were detected in psbA-trnH, rpoB-trnC, rpl16 and atpB-rbcL regions, a relatively large amount of intraspecific variations was detected in the psbC-trnS, rps16 and trnL-F regions. These results suggested that these three cpDNA markers are suitable to assess genetic diversity of the species investigated in this study. In contrast, intraspecific variations were detected in seven taxa except Hedera rhombea and Neolitsea aciculata. Neolitsea sericea and the taxa of Quercus had many polymorphic sites.

      • KCI등재

        상록활엽수 3종의 한반도분포 및 자생북한계지

        이정현,최병희 한국식물분류학회 2010 식물 분류학회지 Vol.40 No.4

        The distribution of three typical warm-temperate evergreen trees, Quercus acuta Thunb., Neolitsea sericea (Blume) Koidz., and Machilus thunbergii Siebold & Zucc., were surveyed on the Korean Peninsula based on field and specimen investigations and the distribution maps of the three species were prepared. The distribution patterns of the species correspond to the south coast floristic region in Korea, which includes the distributional areas of Jeju-do, Isl. Ulleung, the southern coastal areas, and the areas up to the islands around Incheon in the Yellow Sea. The northernmost limit of the distribution of Quercus acuta is Isl. Nap of Incheon in the west, and a new distribution was found at Isl. Ulleung in the East Sea; additionally, the limit of Neolitsea sericea is the Deojoek archipelago of Incheon. The northernmost limit of Machilus thunbergii is Isl. Daecheong of Incheon, which is the highest latitude among those of the three species. This distribution survey of evergreen broad-leaved trees in Korea can be used as basic data for the delimitation of floristic regions and as a bio-indicator of climatic change. 본 연구는 표본과 현지조사를 토대로 대표적 난온대성 상록활엽수인 붉가시나무, 참식나무, 후박나무의 한반도 분포를 조사하고, 각 종의 분포도를 작성하였다. 조사결과 이 종들은 제주도, 울릉도, 남해안 및 서해의 인천 도서지방까지 분포하며, 이는 한반도 남해안아구계와 일치하였다. 붉가시나무의 서쪽 자생북한계지는 인천시 옹진군 덕적면 납도이었으며, 동쪽은 금번조사를 통해 울릉도에서 새로운 자생지가 확인되었다. 참식나무의 자생북한계지는 인천시 옹진군 덕적군도(각흘도, 광대도, 하고도)이었으며, 후박나무의 자생북한계지는 인천시 옹진군 대청도로, 3종중 가장 고위도 까지 분포하였다. 이들 상록활엽수 분포 조사결과는 한반도 식물구계 구분 및 기후변화 생물지표자료로 활용할 수 있을 것이다.

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