• Title/Summary/Keyword: 위상(수)학

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Stability Assessment of FKP System by NGII using Long-term Analysis of NTRIP Correction Signal (NTRIP 보정신호 분석을 통한 국토지리정보원 FKP NRTK 시스템 안정성 평가)

  • Kim, Min-Ho;Bae, Tae-Suk
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.31 no.4
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    • pp.321-329
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    • 2013
  • Despite the advantage of unlimited access, there are insufficient studies for the accuracy and stability of FKP that blocks the spread of the system for various applications. Therefore, we performed a long-term analysis from continuous real-time positioning, and investigated the error characteristics dependent on the size and the surrounding environment. The FKP shows significant changes in the positioning accuracy at different times of day, where the accuracy during daytime is worse than that of nighttime. In addition, the size and deviation of FKP correction may change with the ionospheric conditions, and high correlation between ambiguity resolution rate and the deviation of correction was observed. The receivers continuously request the correction information in order to cope with sudden variability of ionosphere. On the other hand, the correction information was not received up to an hour in case of stable ionospheric condition. It is noteworthy that the outliers of FKP are clustered in their position with some biases. Since several meters of errors can be occurred for kinematic positioning with FKP, therefore, it is necessary to make appropriate preparation for real-time applications.

Development of District-level Planning Support System by using GIS (GIS를 활용한 상세계획 지원시스템의 개발)

  • 고준환;주용수
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.16 no.2
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    • pp.251-258
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    • 1998
  • The purpose of this study is to develop the District-level Planning Support System (DPSS) by using GIS. The district-level planning which is related for district-level control of city, needs the various parcel-level information which is composing the urban physical environment. The information has to be stored and analyzed for recognizing the study area, then the district-level planning will be efficiently managed. The use of GIS in the process of district-level planning is restricted for the creation of thematic map. GIS is not used for the analysis of spatial patterns and planning process. This study evaluates the characteristics of current district-level planning and the basic components of urban physical environment. And the database model is built. The topology among components is defined by using the spatial relationship. Then the spatial query machine for district-level planing is developed by using ArcView 3.1, Avenue and Dialog Extension. This spatial query machine is applied for case study. This study shows 1) the possibility of the district-level planning support system for analyzing spatial relationship, 2) the needs of the up-to-date topographic map showing current building's footlines and the complete integration with cadastral maps, it will reduce the uncertainty in the spatial decision making process, 3) the methodology for the construction of spatial decision making rules, 4) the further study for the using of raster, network, image and three dimension data.

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Measurement of Dynamic Stability Derivatives of Tailless Lamda-shape UAV using Forced Oscillation Method (강제진동 기법을 이용한 무미익 비행체의 동안정 미계수 측정)

  • Yang, Kwangjin;Chung, Hyoungseog;Cho, Donghyun;An, Eunhye;Ko, Joonsoo;Hong, JinSung;Kim, Yongduk;Lee, MyungSup;Hur, Gi-Bong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.44 no.7
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    • pp.552-561
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    • 2016
  • In this experimental study, the dynamic stability derivatives of a tailless lambda-shape UAV are estimated from time history data of aerodynamic moments measured from the internal balance while the test model is forced to oscillate at given frequencies and amplitudes. A 3-axis forced oscillation apparatus is designed to induce decoupled roll, yaw, pitch oscillations respectively. The results show that the roll damping derivatives remain stable at the entire range of angle of attack tested, whereas the pitch damping derivatives become unstable beyond $15^{\circ}$ angle of attack. The amplitude and frequency have little impact on roll damping derivatives while the smaller amplitude and frequency of oscillation improves the pitch stability. The yaw damping derivative values are fairly small as expected for a tailless configuration. The results indicate that the proposed methodology and test apparatus area valid for estimating the dynamic stability derivatives of a tailless UAV.

A Study of Correlations between Air-Temperature of Jeju and SST around Jeju Island (제주도 기온과 주변해역 해수면 온도와의 상관관계에 관한 연구)

  • Jang Seung-Min;Kim Seong-Su;Choi Young-Chan;Kim Su-Gang
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.9 no.1
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    • pp.55-62
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    • 2006
  • Correlations between air-temperature variation and SST variation around Jeju Island have been studied with data JRMO($1924{\sim}2004$) and NFRDI($l971{\sim}2000$). Air-temperature has increased about $0.02^{circ}C/year$ for the period of $1924{\sim}2004$ but relatively high 0.035/year for the last 30 years. SST has increased about $0.024^{circ}C/year$ for the period of $1971{\sim}2000$ and relatively high $0.047^{circ}C/year$ in December. According to the analysis of time series of the two kind of variation, the SST and air-temperature are positively correlated. They are generally in phase, and SST anomaly is similar to air-temperature anomaly as well. Consequently, SST variation has high correlation with air-temperature variation around Jeju Island.

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Tracking Interdisciplinary Relationships between Scientific Researches in Energy Fields using Bibliometic Analysis (과학기술논문을 통한 에너지 연구 분야의 다학제 동태 추적분석)

  • Kang, Jong-Seok;Chung, Hyun-Sang;Lee, Il-Hyung
    • Journal of Korea Technology Innovation Society
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    • v.13 no.4
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    • pp.680-699
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    • 2010
  • In this paper, we attempted to analysis and track dynamic properties of the interdisciplinary relationship between scientific research areas in energy field using bibliometric analysis. We created network maps with SCs (subject categories) defined from $WoS^{\circledR}$ (Web of Science, Thomson Scientific ISI, Philadelphia, USA) using co-occurrence analysis method in order to identify overall disciplines directly linked with energy fields and investigate the change of interaction between SCs as a function of time. From the results of this study, thermodynamics, fuels, chemistry/chemical engineering, and electrochemistry have differentiated into more specific disciplines while the strength of interaction with energy field gradually has increased. Meanwhile, "nuclear physics" was developed to "nuclear science & technology" toward applicable target sector and also the interaction of "environmental science" with "energy generation area" among various energy disciplines recently showed the radical increase as compared with the values of 4 years ago. Finally, through combinative reviews of today's energy policy established by South Korea government, this study will give a help for keeping up with national energy agenda meeting the diverse characteristics of academic disciplines of energy field. In addition, our results support that the use of such network analysis based on bibliometric analysis to discern shifts in academic R&D strategies and target sectors.

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Developing Bibliometric Indicators for Analysis & Evaluation of National R&D Programs (국가연구개발사업의 과학적 성과분석을 위한 새로운 계량지표 개발에 관한 연구)

  • Heo, Jung-Eun;Kim, Hae-Do;Cho, Young-Don;Cho, Suk-Min;Cho, Soon-Ro
    • Journal of Korea Technology Innovation Society
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    • v.11 no.3
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    • pp.376-399
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    • 2008
  • Science and technology (S&T) is one of the most important elements in a nation's competitiveness. In an effort to strengthen their national competitiveness, all countries are focusing on upgrading the level of eir S&T. With these factors in mind, Korea has increased its support of national research and development (R&D). In recent years, this added support has resulted in an increased interest in the effectiveness of R&D. We have made continuous efforts to enhance the accountability and effectiveness of R&D by strengthening performance evaluation and considering R&D evaluation results during the budget review (appropriation) process. In order to change to a performance based system, we need to develop objective and scientific indicators to measure and evaluate the quality of the research performance of R&D programs. One of the primary research outcomes is publications. The impact factor of publications is widely used to evaluate overall journal quality and the quality of the papers published therein. However, the use of impact factors has been criticised because they can vary greatly when works from different subject areas are compared. In order to overcome this limitation, we have developed three kinds of qualitative indicators, which are functions of the impact factor. Two of these qualitative indicators, Modified Rank Normalized Impact Factor and Ordinal Rank Normalized Impact Factor, are based on order statistics (rank) for all journals from a specific specialty. The third qualitative indicator, Relative Field Impact Factor, uses the average impact factor of all journals within a subject category. We also suggest a quantitative indicator, Percentage of Contribution. In this study, we suggest 4 indicators and use them to evaluate the performance of outcomes from three R&D programs supported by the Ministry of Education, Science & Technology. We also perform a simulation study to verify the effectiveness of the proposed indicators. It can be shown that the proposed Ordinal Rank Normalized Impact Factor is the most reliable and effective indicator for comparing research performance across subject categories. However, we recommend using previous indicators in combination with the proposed indicators in this study for the research evaluation of R&D programs.

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Creating Cultural Heritage though 'Silkroadpia' - Reconstructing the Routes of the Baekje Restoration Movement ('실크로드피아(Silkroadpia)'의 활용과 문화유산의 창출 - 백제부흥운동의 경로복원을 중심으로)

  • Cho, Daeyoun
    • The Journal of the Convergence on Culture Technology
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    • v.6 no.1
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    • pp.343-350
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    • 2020
  • In this paper, we present the results of research on the reconstruction of ancient routes of ancient civilization exchange that were once present in the North Jeolla region, which was undertaken by adopting a convergent approach to develop 'Silkroadpia', which is an online platform for the curation and sharing of archaeological and historical spatial data, and 'MEPTA(Multiple Evidence Based Path and Territory Finding Algorithm)'. The results of the research make it possible to reconsider the region's historical identity and its important role in facilitating cultural exchange on the Korean Peninsula and in East Asia. The results can also be used to provide the theoretical basis for the government's land planning policies and for the production of cultural contents that can be used for local regeneration. The ancient route associated with the Baekje Restoration Movement, that took place after the fall of Sabi in 660 CE, was the case study examined in this paper, which discusses the academic value of reconstructing the ancient route, as well as its future use in providing cultural contents.

The Structural Equivalence and Role Equivalence of Container Ports in Asia-Europe Container Shipping Networks (아시아-유럽 컨테이너 해운 네트워크 구성 항만의 구조적 등위성과 역할 등위성)

  • Lee, Sang-Yoon
    • Journal of Korea Port Economic Association
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    • v.32 no.2
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    • pp.105-122
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    • 2016
  • Numerous studies have evaluated the status of seaports. However, the majority of the research has approached this topic from the view-point of port capabilities, including locational advantage, infrastructure, productivity, and competitiveness. The position and/or role of a port can be understood more precisely and comprehensively by considering the interconnectivity among ports making up enormous global transportation networks. The main objective of this study is to compare the status of 82 container ports on the trunk shipping routes between Asia and Europe by applying the concepts of structural equivalence and role equivalence proposed by the social network analysis method. Network similarities and differences among competing ports in the regions are assessed by analysing their structural equivalence. Furthermore, the hierarchical structures of the ports located on the trunks between Asia and Northwest Europe and between Asia and the Mediterranean are constructed by evaluating their role equivalence. The results of this empirical research shows that Singapore and Rotterdam possess the most significant positions on the ocean corridors between Asia and Northwest Europe. Singapore also holds a leading position on the Asia-Mediterranean shipping route. Lastly, no ports located in the Middle East or Mediterranean regions have an equivalent weight to those of Rotterdam, Hamburg, Antwerp on the Asia-Northwest Europe route.

The Study of BIFF Street Renovation Plan (부산 영화의 거리 조성계획)

  • Yu, Yeon-Seo;Yun, Eun-Joo;Kang, Young-Jo
    • Journal of the Korean Institute of Landscape Architecture
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    • v.42 no.2
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    • pp.1-9
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    • 2014
  • This study is the renovation plan for BIFF(Busan International Film Festival) street themed movies, which is an internationally known film festival. The aim of this is the regional economic vitalization. The first step of the plan sets up position through the case study of the Theme Street. The theme for each road space is related with movies and realizes the unificative images for each road. Images between the Busan Cinema Center and BUSAN MARINA are introduction of the road and the subject of this road is greeting with movies. The history of movies are printed on the pavement, some sections are made with red blocks for recollecting the red carpet. The next section from the BUSAN MARINA to MARINE CITY is set up being close with movies. In this section, sculptures of filmmaking and theme benches are installed for indirect experiences. The theme from MARINE CITY to DONGBAEK ISLANDS is playing and enjoying with movies. It is made more fun with the installation of super graphic and trick art. The theme from DONGBAEK ISLANDS to HAEUNDAE is farewell with movies. It is expressed by music on pavement and musical fountain. The last section in the theme road from HAEUNDAE to MOONTAN ROAD shows the concept memories after farewell. It is a half way to Moonten Road. The Milky Way pavement and Milky Way square are made by installing the optical fibers.

Study on Signal Processing in Eddy Current Testing for Defects in Spline Gear (스플라인 기어부 결함의 와전류검사 신호처리에 관한 연구)

  • Lee, Jae Ho;Park, Tae Sung;Park, Ik Keun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.36 no.3
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    • pp.195-201
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    • 2016
  • Eddy current testing (ECT) is commonly applied for the inspection of automated production lines of metallic products, because it has a high inspection speed and a reasonable price. When ECT is applied for the inspection of a metallic object having an uneven target surface, such as the spline gear of a spline shaft, it is difficult to distinguish between the original signal obtained from the sensor and the signal generated by a defect because of the relatively large surface signals having similar frequency distributions. To facilitate the detection of defect signals from the spline gear, implementation of high-order filters is essential, so that the fault signals can be distinguished from the surrounding noise signals, and simultaneously, the pass-band of the filter can be adjusted according to the status of each production line and the object to be inspected. We will examine the infinite impulse filters (IIR filters) available for implementing an advanced filter for ECT, and attempt to detect the flaw signals through optimization of system design parameters for detecting the signals at the system level.