• 지적과 국토정보
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• 제44권1호
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• pp.151-164
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• 2014

본 논문에서는 브이월드 이용 활성화를 위한 가이드 제작에 관해 연구하였다. 브이월드 만족도 조사를 통해 대상자를 분류하여 방문 목적 등을 조사하였으며, 브이월드 사용자의 방문 목적에 따라 초급, 중급, 고급으로 분류하였다. 특히 본 논문에서는 90% 이상의 지도계열 서비스 사용자를 중심으로 초급 가이드 작성에 대해 연구하였다. 브이월드의 서비스 기능 분석, 초급 가이드에 대한 구성 방안, 콘텐츠 작성, 가이드 제작 방법 개발을 위해 다양한 통계분석 및 사회 전반적인 이슈 조사를 수행하였다. 본 연구를 통해 일반인이 보다 쉽게 국가공간정보를 국민에게 제공하는 브이월드에 접근할 수 있는 계기가 되었으면 한다.

• 식물분류학회지
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• 제34권1호
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• pp.37-41
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• 2004

T. Nakai는 1911년 Flora Koreana vol. II에 러시아 식물분류학자인 V. L. Komarov의 1897년 북한 채집 표본을 120여점 인용하였다. Nakai가 언급한 북한의 지명은 약 65개로서 Komarov의 채집지명의 상당 부분에 해당된다. Nakai가 언급한 지명은 러시아발음에 근간을 두고 로마자로 표기하였는데 최근 혹은 과거 지도에서 정확한 채집지명을 확인하기가 매우 어렵다. 본 연구는 Flora Koreana II에 기재된 채집지명을 과거 발표된 러시아와 일본 번역서인 만주식물지와 표본레이블 등의 자료를 근간으로 Nakai가 언급한 원명과, 한자 지명, 현재 지명의 로마자표기, 위도와 경도, 출처의 페이지 등을 도표로 제시하여 정리하였다.

• 소성∙가공
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• 제10권4호
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• pp.347-354
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• 2001

Compression tests were carried out to investigate the hot-deformation behavior of Ti-6Al-4V alloy in the temperature range of $915^{\circ}C$ to $1015^{\circ}C$ and the strain rate range of $10^{-3}s^{-i}$ to $10s^{-1}$. Under the given test conditions, the hot-deformation of Ti-6Al-4V alloy was mainly led by dynamic recovery rather than by dynamic recrystallization. The activation energy for the plastic deformation in $\alpha+\beta$ field was about 894 kJ/mol and $\beta$ field was 332kJ/mo1. Processing map for hot working are developed on the basis of the variations of efficiency of power dissipation($\eta$=2m/m＋1) and flow instability criterion using the dynamic material model. The optimum process condition in the ($\alpha＋\beta$) field was obtained at the temperature ranges of $930^{\circ}C$ to $955^{\circ}C$$^{\circ}C$ and a strain rate of $10^{-3}s{-1}$.

• Journal of applied mathematics & informatics
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• 제34권3_4호
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• pp.227-237
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• 2016

In this paper we introduce a new graph labeling called k-prime cordial labeling. Let G be a (p, q) graph and 2 ≤ p ≤ k. Let f : V (G) → {1, 2, . . . , k} be a map. For each edge uv, assign the label gcd (f(u), f(v)). f is called a k-prime cordial labeling of G if |v_f (i) − v_f (j)| ≤ 1, i, j ∈ {1, 2, . . . , k} and |e_f (0) − e_f (1)| ≤ 1 where v_f (x) denotes the number of vertices labeled with x, e_f (1) and e_f (0) respectively denote the number of edges labeled with 1 and not labeled with 1. A graph with a k-prime cordial labeling is called a k-prime cordial graph. In this paper we investigate the k-prime cordial labeling behavior of a star and we have proved that every graph is a subgraph of a k-prime cordial graph. Also we investigate the 3-prime cordial labeling behavior of path, cycle, complete graph, wheel, comb and some more standard graphs.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권8호
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• pp.1933-1954
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• 2013

Multiple wireless devices are being widely deployed in Intelligent Transportation System (ITS) services on the road to establish end-to-end connection between vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) networks. Vehicular ad hoc networks (VANETs) play an important role in supporting V2V and V2I communications (also called V2X communications) in a variety of urban environments with distinct topological characteristics. In fact, obstacles such as big buildings, moving vehicles, trees, advertisement boards, traffic lights, etc. may block the radio signals in V2X communications. Their impact has been neglected in VANET research. In this paper, we present a realistic and efficient radio propagation model to handle different sizes of static and moving obstacles for V2X communications. In the proposed model, buildings and large moving vehicles are modeled as static and moving obstacles, and taken into account their impact on the packet reception rate, Line-of-sight (LOS) obstruction, and received signal power. We use unsymmetrical city map which has many dead-end roads and open faces. Each dead-end road and open faces are joined to the nearest edge making a polygon to model realistic obstacles. The simulation results of proposed model demonstrates better performance compared to some existing models, that shows proposed model can reflect more realistic simulation environments.

• 한국분말재료학회지
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• 제21권4호
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• pp.277-285
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• 2014

The effects of processing parameters on the flow behavior and microstructures were investigated in hot compression of powder metallurgy (P/M) Ti-6Al-4V alloy. The alloy was fabricated by a blended elemental (B/E) approach and it exhibited lamellar ${\alpha}+{\beta}$ microstructure. The hot compression tests were performed in the range of temperature $800-1000^{\circ}C$ with $50^{\circ}C$ intervals, strain rate $10^{-4}-10s^{-1}$, and strain up to 0.5. At $800-950^{\circ}C$, continuous flow softening after a peak stress was observed with strain rates lower than $0.1s^{-1}$. At strain rates higher than $1s^{-1}$, rapid drop in flow stress with strain hardening or broad oscillations was recorded. The processing map of P/M Ti-6Al-4V was designed based on the compression test and revealed the peak efficiency at $850^{\circ}C$ and $0.001s^{-1}$. As the processing temperature increased, the volume fraction of ${\beta}$ phase was increased. In addition, below $950^{\circ}C$, the globularization of phase at the slower strain rate and kinking microstructures were found. Based on these data, the preferred working condition of the alloy may be in the range of $850-950^{\circ}C$ and strain rate of $0.001-0.01s^{-1}$.

• 대한방사선기술학회지:방사선기술과학
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• 제45권1호
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• pp.41-47
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• 2022

The purpose of this study is to apply a deep learning model that can distinguish lung perfusion and lung ventilation images in nuclear medicine, and to evaluate the image classification ability. Image data pre-processing was performed in the following order: image matrix size adjustment, min-max normalization, image center position adjustment, train/validation/test data set classification, and data augmentation. The convolutional neural network(CNN) structures of VGG-16, ResNet-18, Inception-ResNet-v2, and SE-ResNeXt-101 were used. For classification model evaluation, performance evaluation index of classification model, class activation map(CAM), and statistical image evaluation method were applied. As for the performance evaluation index of the classification model, SE-ResNeXt-101 and Inception-ResNet-v2 showed the highest performance with the same results. As a result of CAM, cardiac and right lung regions were highly activated in lung perfusion, and upper lung and neck regions were highly activated in lung ventilation. Statistical image evaluation showed a meaningful difference between SE-ResNeXt-101 and Inception-ResNet-v2. As a result of the study, the applicability of the CNN model for lung scintigraphy classification was confirmed. In the future, it is expected that it will be used as basic data for research on new artificial intelligence models and will help stable image management in clinical practice.

• 천문학회보
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• 제40권1호
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• pp.62.1-62.1
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• 2015

Polarization of the light reflected off the Moon provides information on the size and composition of the particles in the lunar regolith. The mean particle size of the regolith can be estimated from the combination of the albedo and degree of polarization, while the color ratio of the parallel-component polarization (CP) has been suggested to be related to the amount of nanophase metallic iron (npFe^0) inside the regolith particles. Both the mean size and npFe^0 abundance of the particles have been used as maturity indicators of the regolith since sustained impacts of high energy particles and micro-meteoroids cause comminution of particles and production of npFe^0. Based on our multispectral polarimetric observations of the whole near side of the Moon in the U, B, V, R, and I bands, we compare the maps of the mean particle size, CP, and the optical maturity (OM). We find that the mean particle size map is sensitive to the most immature (~0.1 Gyr) soil, the OP map to the intermediate immaturity (a few 0.1 Gyr) soil, and the CP map to the least immature (~1 Gyr) soil.

• 한국환경생태학회지
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• 제29권1호
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• pp.69-80
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• 2015

Studies on Trapa of Korean, Japanese, and Chinese origins have been generally limited to currently living Trapa, thereby demonstrating the lack of phylogenetic approaches. In the present study, we conducted a numerical taxonomic study on 34 Korean origin Trapa species newly discovered in peat deposits. By using the numerical taxonomy as well as geological data, we created an appearance map based on the periods and taxonomic groups of the Korean Trapa. Further, by using this appearance map, we reviewed the limitations that exist in the taxa and simultaneously discussed the adaptational environment of Trapa in each period. Although other studies have discussed new variants of Trapa worldwide, including T. litwinowii V. vassil. var. chihuensis S.F.Guan & Q.Lang of China (Guan and Lang, 1987), the present study is significant because it provides data on the origin of Korean Trapa species. The availability of such data is essential in determining the adaptational environment of the presently living Trapa. To our knowledge, this is the first report of approximately 10 newly discovered and other presently living species of Trapa. Further, the appearance map in the present study allows the use of the 10 newly discovered species and variants of 34 Trapa species indigenous to South Korea for over 1000 years, for a comparison with the currently living Trapa species. Thus, the present study results could serve as important basic data to understand the adaptational environment of the genus Trapa. from the past to the present in Korea.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.209-209
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• 2012

전자의 에너지를 측정하기 위한 분석장치는 원자핵물리뿐만 아니라 화학과 생물학 등 다양한 분야에 걸쳐 매우 유용하게 사용될 수가 있다. 특히 최근에 극고속 과학과 관련해서 매우 짧은 펄스인 아토초 펄스의 발생에 대한 특성평가를 위해 매우 중요한 장치로 사용되고 있다. 그 중 VMI (Velocity Map Imaging) 방법은 TOF (Time of Flight) 방법과 유사하지만, CCD 카메라를 추가로 사용하여 이차원 이미지를 얻음으로써 전자의 운동에너지 및 각도 분포에 대한 정보를 얻을 수 있고 또한 전극에 인가되는 전압은 TOF와 달리 매우 높다. 이번 개발에서는 기존의 전극 렌즈의 geometry와 비교해서 VMI Spectrometer 전극 렌즈의 수를 늘려 multi-electrode concept을 도입함으로써 높은 운동에너지(~1000 eV)를 가진 전자들을 MCP detector상에서 imaging 하는데 있어 높은 공간 분해능(resolution)을 갖도록 설계하고, 또한 높은 사양의 MCP detector 및 CCD 카메라를 이용하여 시간 분해능을 높임으로써 아토초 펄스를 이용한 극고속 실험에 이용 가능하도록 제작하였다.