• 한국정보과학회논문지:데이타베이스
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• 제37권4호
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• pp.203-208
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• 2010

본 논문은 단일무선방송채널환경에서 힐버트곡선과 최소영역사각형을 이용하여 공간데이터를 방송하고 이를 가지고 k-최근접질의 처리를 효과적으로 처리하는 기법에 관한 논문이다. 기존 방식은 k-최근접질의 처리시 백트랙킹문제가 발생하여 질의처리에 오랜 시간이 걸리거나 검색범위를 빠르게 줄이지 못하여 많은 정보를 수신해야 하는 단점이 존재하였다. 제안하는 방법은 공간데이터를 힐버트 곡선 순서대로 방송하되 방송중인 공간데이터를 제외한 나머지 공간데이터를 최소영역사각형으로 그룹화하고 이를 인덱스 테이블로 구성하는 방법이다. 그리고 이를 이용하여 클라이언트가 알려지지 않은 데이터의 위치를 예측하여 빠르게 검색범위를 줄여나가 불필요한 정보를 제거하여 적은 튜닝시간과 접근지연시간을 갖도록 하는 것이다.

• 한국조경학회지
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• 제35권6호
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• pp.64-73
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• 2008

The purpose of this study is to classify urban green space, to assess an imbalance by an administrative district (Dong), and to establish the management zone of urban green spaces for the construction of an environmental city in Changwon. The spatial data of 1:5,000 digital maps, park data in Changwon, land cover by the Ministry of Environment, and IKONOS satellite images from 2003 were used for this analysis. The assessment of the imbalance of urban green spaces was analyzed with the Lorenz curve and Gini's coefficient. The establishment of the management zone was performed by network analysis of GIS. The results of this study are as follows: the urban green spaces were classified as a park green space, a natural green space, and a riparian green space. According to the results of assessment of the imbalance of green spaces, Gini's coefficient was analyzed at higher than 0.4. Thus, the spatial imbalance of urban green spaces in Changwon was evident. The management zones to solve the imbalance were established: "rich zone", "fair zone", "poor zone" and "broken zone". Therefore, the rich and fair zones which have rich green spaces must maintain the good conditions through analysis of the green network and a survey of civic attitudes. The poor and broken zones which have poor green spaces must improve quality and quantity through creation of additional green spaces, construction of an eco-industrial park, and utilization of children's parks and pocket parks.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.15-18
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• 2003

This paper proposes a color matching 3D look-up table simplifying the complex color matching procedure between a monitor and a mobile display device. In order to perform color matching, it is necessary to process color of image in the device independent color space like CIEXYZ or CIELAB. We improved the S-curve model to have smaller characterization error than tolerance error. Also, as a result of the experiments, we concluded that the color matching look-up table with 64(4$\times$4$\times$4) is the smallest size allowing characterization error to be acceptable.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권10호
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• pp.5159-5178
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• 2018

Network Intrusion detection is a rapidly growing field of information security due to its importance for modern IT infrastructure. Many supervised and unsupervised learning techniques have been devised by researchers from discipline of machine learning and data mining to achieve reliable detection of anomalies. In this paper, a deep convolutional neural network (DCNN) based intrusion detection system (IDS) is proposed, implemented and analyzed. Deep CNN core of proposed IDS is fine-tuned using Randomized search over configuration space. Proposed system is trained and tested on NSLKDD training and testing datasets using GPU. Performance comparisons of proposed DCNN model are provided with other classifiers using well-known metrics including Receiver operating characteristics (RoC) curve, Area under RoC curve (AuC), accuracy, precision-recall curve and mean average precision (mAP). The experimental results of proposed DCNN based IDS shows promising results for real world application in anomaly detection systems.

• Computers and Concrete
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• 제11권5호
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• pp.399-410
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• 2013

A nonlinear finite element analysis of R/C hybrid deep T-beam with web opening subjected to pure torsion is presented. Hexahedral 8-nodes and space truss element were used for modeling concrete and reinforcement. The reinforcement was assumed perfectly bonded to the corresponding nodes of the concrete element. The constitutive relations for concrete and reinforcement are based on the modified field theory and elastic perfectly plastic. The smear crack approach was adopted for modeling the crack. The torque-twist angle relationship curve based on the finite element analysis was compared to the experimental results. The comparison shows that the curve of torque-twist angle predicted by the nonlinear finite element analysis is linear before cracking and close to the experimental result. After cracking, the curve becomes nonlinear and stiffer compared to the experimental result.

• 호남수학학술지
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• 제43권3호
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• pp.453-463
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• 2021

In this study, tubular surfaces that play an important role in technological designs in various branches are examined for the case of the base curve is not satisfying the fundamental theorem of the differential geometry. In order to give an alternative perspective to the researches on tubular surfaces, the modified orthogonal frame is used in this study. Firstly, the relationships between the Serret-Frenet frame and the modified orthogonal frame are summarized. Then the definitions of the tubular surfaces, some theorems, and results are given. Moreover, the fundamental forms, the mean curvature, and the Gaussian curvature of the tubular surface are calculated according to the modified orthogonal frame. Finally, the properties of parameter curves of the tubular surface with modified orthogonal frame are expressed and the tubular surface is drawn according to the Frenet frame and the modified orthogonal frame.

• 천문학회보
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• 제45권1호
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• pp.39.3-40
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• 2020

For the space weather research, KASI (Korea Astronomy and Space Science Institute) is developing the SNIPE (Small-scale magNetospheric and Ionospheric Plasma Experiment) mission, which consists of four 6U CubeSats of ~10 kg. Besides of space weather research, the SNIPE mission has another astrophysical objective, detecting Gamma-Ray Bursts(GRB). By cross-correlating the light curves of the detected GRBs, the fleet shall be able to determine the time difference of the arriving signal between the satellites and thus determine the position of bright short bursts with an accuracy ~100'. To demonstrate the technology of the GRB observation, CSI gamma-ray detectors combined with GPS and IRIDIUM communication modules are placed on each SNIPE CubeSat. The time of each spacecraft is synchronized and when the GRB is detected, the light curve will be transferred to the Mission Operation Center (MOC) by IRIDIUM communication module. By measuring time difference of each GRB signals, the technology for localization of GRB will be proved. If the results show some possibilities, we can challenge the new astrophysical mission for investigating the origin of GRB.

• Journal of Astronomy and Space Sciences
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• 제17권1호
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• pp.99-106
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• 2000

When a deployed probe is biased by a high positive potential during a space experiment, the payload is induced to a negative voltage in order to balance the total current in the whole system. The return currents are due to the responding ions and secondary electrons on the payload surface. In order to understand the current collection mechanism, the process was simulated with a combination of resistor, inductor, and capacitor in SPICE program which was equivalent to the background plasma sheath. The simulation results were compared with experimental results from SPEAR-3 (Space Power Experiment Aboard Rocket-3). The return current curve in the simulation was compatible to the experimental result, and the simulation helped to predict the transient plasma response to a high voltage during the plasma sheath formation.

• 대한수학회보
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• 제51권4호
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• pp.957-964
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• 2014

In this paper, we prove that there is no branch point in the Lorentz space (M, d) which is the limit space of a sequence {($M_{\alpha},d_{\alpha}$)} of compact globally hyperbolic interpolating spacetimes with $C^{\pm}_{\alpha}$-properties and curvature bounded below. Using this, we also obtain that every maximal timelike geodesic in the limit space (M, d) can be expressed as the limit curve of a sequence of maximal timelike geodesics in {($M_{\alpha},d_{\alpha}$)}. Finally, we show that the limit space (M, d) satisfies a timelike triangle comparison property which is analogous to the case of Alexandrov curvature bounds in length spaces.

• 천문학논총
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• 제24권1호
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• pp.83-91
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• 2009

We have designed data processing server system to include data archiving, photometric processing and light curve analysis for KMTNet (Korea Microlensing Telescope Network). Outputs of each process are reported to the main photometric database, which manages the whole processing steps and archives the photometric results. The database is developed using ORACLE 11g Release 2 engine. It allows to select objects applying any set of criteria such as RA/DEC coordinate and Star ID, etc. We tested the performance of the database using the OGLE photometric data. The searching time for querying 70,000,000 records was under 1 second. The database is fully accessed using query forms via web page.