• 한국해양학회지
• /
• v.29 no.2
• /
• pp.83-94
• /
• 1994

Two-dimensional tidal and tidal residual currents in Chinhae Bay are investigated by field observations, hydraulic and numerical experiments. The results of hydraulic and numerical model experiments roughly coincide with the field measurements. Maximum tidal currents during the spring and neap tides in Kaduk and Kyunnaeryang channel and the central channel of Chinhae Bay are strong as 90 to 110 and 30 to 40 cm/s respectively, and strong tidal residual currents having numerous eddies take place. Maximum tidal currents during the spring and neap tides in the western and northern parts of the bay are weak as below 30 and 10 cm/s respectively, and also tidal residual currents are relatively weak. Tidal residual currents in the northern part of Kajo-do go toward the north, whereas the currents in the southern part move down the bay, and the currents rotating clockwise occur around Bu-do. The surface currents in the bay depend strongly on the wind and river inflow, and such phenomena are more remarkable during he neap tide than the spring tide.

• Journal of agriculture & life science
• /
• v.46 no.2
• /
• pp.1-8
• /
• 2012

This study is a precedent study for deriving transfer function model between growing stock and forest management policies. Its goal is to solve the multicollinearity between forest works inducing growing stock changes through principal component analysis using annual time series data from 1997 to 2008. As the results, the total explanatory power showed 91.4% on the summarized 3 principal components. They were renamed 'good forest management' 'pest & insets management' 'forest fires' for conceptualization on the derived each component.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.23 no.9
• /
• pp.1146-1151
• /
• 2019

Histogram H is an x-monotone rectilinear polygon with a horizontal edge, called by a base, connecting the leftmost vertical edge and the rightmost vertical edge. Here the rectilinear polygon is a polygon with only horizontal and vertical edges and the x- monotone polygon P is a polygon in which every line orthogonal to the x-axis intersects P at most twice. Walking counterclockwise on the boundary of a histogram H yields a sequence of left turns and right turns at its vertices. Conversely, a given sequence of the turns at the vertices can be realized by a histogram. In this paper, we consider the problem of finding a histogram to realize a given turn sequence. Particularly, we will find the histograms to minimize its area and its bounding box. It will be shown that both of the problems can be solved by linear time algorithms.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.41 no.4
• /
• pp.30-39
• /
• 2023

This study aims to identify the value of Incheon Freedom Park as a 'historic urban park' through the historical transition process of the park and surrounding areas. To this end, this study uses a time series analysis, as research method, based on old maps and aerial photographs to investigate the changes in the park over time and to interpret them based on the historical and cultural changes in modern and contemporary history. As a result of the study, the park not only has (1) evidence of major events in modern and contemporary history, but also (2) historical value as an urban park based on the first urban plan in Korea, and (3) very important heritage value that shows the rapidly changing civic life in modern and contemporary times. However, despite the identification of heritage values in this study, further research is needed to explore and excavate in-depth data on the park in order to more clearly identify, restore, and utilize the heritage values of the park.

• The Korean Journal of Applied Statistics
• /
• v.37 no.2
• /
• pp.255-263
• /
• 2024

GDP represents the total market value of goods and services produced by all economic entities, including households, businesses, and governments in a country, during a specific time period. It is a representative economic indicator that helps identify the size of a country's economy and influences government policies, so various studies are being conducted on it. This paper presents a GDP growth rate forecasting model based on a dynamic factor model using key macroeconomic indicators of G20 countries. The extracted factors are combined with various regression analysis methodologies to compare results. Additionally, traditional time series forecasting methods such as the ARIMA model and forecasting using common components are also evaluated. Considering the significant volatility of indicators following the COVID-19 pandemic, the forecast period is divided into pre-COVID and post-COVID periods. The findings reveal that the dynamic factor model, incorporating ridge regression and lasso regression, demonstrates the best performance both before and after COVID.

• Land and Housing Review
• /
• v.12 no.3
• /
• pp.11-26
• /
• 2021

With the increasing demand for office space, there have been questions on how office rent distribution produces a change in the urban spatial structure in Seoul. The purpose of this paper is to investigate a relative price gradient and to present a time-series model that can quantitatively explain the dynamic changes in the urban spatial structure. The analysis was dealt with office rent above 3,306 m² for the past 10 years from 1Q 2010 to 4Q 2019 within Seoul. A modified repeat sales model was employed. The main findings are briefly summarized as follows. First, according to the estimates of the office price gradient in the three major urban centers of Seoul, the CBD remained at a certain level with little change, while those in the GBD and the YBD continued to increase. This result reveals that the urban form of Seoul has shifted from monocentric to polycentric. This shows that the spatial distribution of companies has gradually accelerated decentralized concentration implying that the business networks have become significant. Second, contrary to small and medium-sized office buildings that have undertaken no change in the gradient, large office buildings have seen an increase in the gradient. The relative price gradients in small and medium-sized buildings were inversely proportional among the CBD, the GBD, and the YBD, implying their heterogeneous submarkets by office rent movements. Presumably, those differences in the submarkets were attributed to investment attraction, industrial competition, and the credit and preference of tenants. The findings are consistent with the hierarchical system identified in the Seoul 2030 Plan as well as the literature about Seoul's urban form. This research claims that the proposed method, based on the modified repeat sales model, is useful in understanding temporal dynamic changes. Moreover, the findings can provide implications for urban growth strategies under rapidly changing market conditions.

• Journal of the Korean earth science society
• /
• v.25 no.7
• /
• pp.532-544
• /
• 2004

The purpose of this study is to analyze the concept concerned with Earth's rotation as passed by tenth graders whose interest in earth's rotation and learning styles were varied. To examine student's interest in the Earth's rotation, 4students (visual-verbal learning style student with much interest, visual learning style student with much interest, visual learning style student with little interest, and verbal learning style student with little interest) were chosen for study. Personal interview was used for this study. To probe students' conception in varied ways, they were allowed to make gesture and draw pictures through data collection process, except for interviews. And the data were analyzed one by one. The result of this study were as follows: First, the student with much interest was faster to answer the questions about Earth's rotation than the one with little interest. Also he comprehended better and was able to explain reasons coherently. Second, there was little difference according to student's learning style. Third, one of the repeated misconception was direction. For thinking that is the right side is the east side, students have misconception that the sun goes from right to left and stars in north sky move clock-wise.

• The Journal of the Petrological Society of Korea
• /
• v.11 no.3_4
• /
• pp.182-199
• /
• 2002

We attempted to show the evolution of the magma and the geochemical characteristics of dikes and dike swarms by using the petrographic and geochemical data from 287 dikes, SE Korea. The dikes can be divided into mafic, intermediate, and felsic dikes in the field. And each of them is subdivided into three groups, two groups, and two groups, respectively. The group (I) among the mafic dikes most pervasively occurs and are distributed in both sides of the Yeonil Tectonic Line (YIL), which petrographic and geochemical characteristics are the same. These facts thus, strongly support the results of the previous studies which showed that they were intruded contemporaneously and that YTL was a main tectonic line which restricted the crustal clockwise rotation during the Early Miocene. The geochemical characteristics are discriminated according to the seven groups divided petrographically. The mafic, intermediate and felsic dikes belong to basalt and basaltic andesite, andesite and facile, and rhyolite, respectively, and the magmas mostly belong to calc-alkaline series. The geochemical data indicate that there were the fractional crystallizations of olivine, clinopyroxene, and plagioclase in the mafic dikes. And the content of characteristic elements and tectonic discrimination diagrams show that the dikes were formed from the magma related to the subduction of plate and that the tectonic setting was related to orogenic volcanic arc.

• Science of Emotion and Sensibility
• /
• v.18 no.4
• /
• pp.3-14
• /
• 2015

This study has extracted observation data by spatial factor for the analysis of subjects' selective attention with the objects of public space at the entrance of subway stations. The methods extracting observation data can be summarized as the following. First, the frequency analysis by lattice was prevalent for those methods, but there is a limitation to the analysis of the observation data. On the contrary, the method extracting observation data by factor applied in this study can make it clear if any sight is concentrated on any particular factors in a space. Second, the results from the extracted data corresponding to the observation area can be objectified while the method setting up the observation area by applying the radius of fovea. Third, time-sequential trace of observation results of relevant factors was possible through hourly analysis of spatial factors. The consideration of the results of "corresponding spatial scope" which is the object of this study will reveal that the more the observation time, the less the degree of attention it receives. Fourth, the frequency of observation superiority was applied for the analysis of the sections with selective attention by time scope; this revealed that men and women had intensive observation in time scope I (52.4 %) and in time scope IV (24.0 %), respectively.

• Information and Communications Magazine
• /
• v.24 no.7
• /
• pp.26-35
• /
• 2007

최근 몇 년간 유비쿼터스 서비스를 구현하기 위한 핵심 기술 중 하나인 무선 센서 네트워크에 대한 관심이 높아지고 있다. 무선 센서 네트워크 기술은 물류, 유통, 환경 감시, 홈오토메이션, 군사 분야 등 다양한 분야에 적용 될 수 있기 때문에 앞으로 관련 분야의 시장 또한 커질 것으로 예상되고 있다 [1]. 무선 센서 네트워크는 기존 유선 센서 네트워크나 무선 네트워크 환경과는 많은 차이를 가진다. 우선 극도로 제한된 시스템 자원만을 가질 수 있으며, 열악한 환경 속에서 무선매체를 통해 유기적으로 동작하여야 하는 특징을 가지고 있다. 적게는 수십 개에서 많게는 수백, 수천 개의 자율적인 하드웨어 노드들로 구성되는 무선 센서 네트워크에서 제한된 자원을 효과적으로 활용하기 위해서는 센서 노드에 적합한 운영체제가 필수적으로 요구된다. 지난 몇 년간 센서 노드하드웨어의 발달과 더불어 많은 센서 네트워크용 초소형 운영체제가 개발되어왔다. 현재 많이 알려져 있는 센서 네트워크용 OS로는, 가장 활발한 참여를 보이고 있는 TinyOS[3]부터 SOS[4], MANTIS[5], Contiki[6], T-kernel[7] 등이 있으며, 국내 기술로 개발된 Nano-Qplus[8] 등이 존재한다. 본고에서는 우선 센서 네트워크에 대한 배경 지식과 플랫폼 등에 대한 내용을 간단히 다루고, 본론에서 센서 네트워크용 운영체제가 가져야 할 조건과 현재 개발되어 있는 센서 네트워크 OS들의 특징에 대해 간략히 살펴보도록 하겠다. 또한 센서 네트워크 OS와 밀접한 연관성을 가지는 분야에 대해 간단히 살펴보고, 마지막으로 앞으로의 방향에 대해 알아본다.고려해 볼 때 atlas의 장축의 시계방향 회전은 액티베이터의 사용 효과로 생각되며, 이는 차후 II급 부정교합자에서 액티베이터 치료 효과를 판단하는 또 하나의 지표가 될 수 있다고 생각한다.인해 한반도를 포함한 동아시아 대륙이 태평양판 쪽으로 밀려감으로써 섭입하던 태평양판의 각도가 급해져 동아시아 연변에 강력한 흡입력이 발생하였으며, 이 때문에 태평양판의 운동 방향이 북북서에서 서북서방향으로 회전되었을 가능성이 있다. 따라서 약 51 Ma부터 한반도 동남부에는 지판 경계의 강력한 흡입력으로 동서 내지 서북서-동남동의 인장력이 작동되어 B그룹 암맥군이 관입한 것으로 해석된다.Ledge는 세 군 모두에서 나타나지 않았다. 4. 파일 binding 횟수는 MC군이 가장 적고 PT군이 가장 많았다 (p < 0.05). 이상의 결과를 볼 때, Mtwo 전동 파일을 crown-down technique으로 사용하는 것이 single length technique과 유사한 성형 효율을 보이면서도 더 안전할 것으로 추정된다.고 1명(3%)에서 원격전이를 보였다. 치료 중 급성 합병증으로 11명(37%)에서 RTOG grade 1-2의 장염을 보였으며 1명은 대장의 천공이 발생하여 수술로 치유되었다. 12명(40%)에서 RTOG grade 1-2의 급성 방광염을 보였다. 3명(10%)에서 RTOG grade 1-2의 백혈구 감소증이 보였으며 1명에서 심한 백혈구 감소증(RTOG grade 4)이 나타났으나 회복되어 치료를 완료하였다. 만성 합병증으로 5명(15%)에서 RTOG grade 1-2의 만성 장염을 보였으며 별다른 치료 없이 지내고 있으며