• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.262-267
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• 2008

Recently, landslides frequently occur on natural slope and/or man-made cut slope during periods of intense rainfall. With a rapidly increasing population on or near steep terrain, landslides have become one of the most significant natural hazards. Thus, it is necessary to protect people from landslides and to minimize the damage of houses, roads and other facilities. To accomplish this goal, many landslide monitoring systems have been developed throughout the world. In this paper, a simple landslide detection system that enables people to escape the endangered area is introduced. The system is focused on the debris flows which happen frequently during periods of intense rainfall. The system is based on the wireless sensor network (WSN) that is composed of wireless sensor nodes, gateway, and remote server system. Wireless sensor nodes and gateway are deployed by commercially available Microstrain G-Link products. Five wireless sensor nodes and one gateway are installed at the test slope for detecting ground movement. The acceleration and inclination data of test slope can be obtained, which provides a potential to detect landslide. In addition, thresholds to determine whether the test slope is stable or not are suggested by a series of numerical simulations, using geotechnical analysis software package. It is obtained that the alarm should be issued if the x-direction displacement of sensor node is greater than 20mili-meters and the inclination of sensor node is greater than 3 degrees. It is expected that the landslide detection method using wireless senor network can provide early warning where landslides are prone to occur.

• Journal of Korean Elementary Science Education
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• v.21 no.1
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• pp.13-24
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• 2002

This study examined the knowledge structure constructed by children before formal instruction, and successive changes in the structural complexity of knowledge during the learning of the 'Structure and Function of Plants' unit. The researchers let the 5th graders draw the first draft of their concept maps in order to examine the pre-existing knowledge structure concerned with the unit and also four concept maps after completing every fourth lesson. Each concept map drawn by children on the basis of the previous one showed the degree of their current understanding on the structure and function of plants. The results revealed that only two levels of hierarchy and five relationships among the components of the first concept map(relationship, hierarchy, cross link and example) were proven to be valid in terms of conceptual relevance. According to the standard map, there was no change in hierarchy from the 2nd to the 3rd map, and in example from the 2nd to the 4th map. However, the gradual and successive increases of the scores in all components appeared in the children's maps throughout the unit. Knowledge restructuring occurred strongly in the early periods from the 1st to the 6th lesson, and the significant stable changes in tuning and accretion appeared throughout the whole lessons. The results also showed that there were no significant gender differences on the 5th grader's knowledge structuring.

• Journal of information and communication convergence engineering
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• v.15 no.3
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• pp.143-150
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• 2017

Absorption of microwave radio frequency signal by atmospheric rain is prevalent at frequencies above 10 GHz. This paper presents the studies on rain attenuation at 18 GHz for 3.2 km experimental link between Khumdang (Korea Telecom, KT station) and Icheon (National Radio Research Agency, RRA station). The received signal data for rain attenuation and rain rate were collected at 10 second intervals over a three year periods from 2013 to 2015. Out of several models, the paper present discussion and comparison of ITU-R P.530-16 model, Moupfouma model, Da Silva Mello model along with suitable rain attenuation prediction method. The limitation of research lies on the experimental system that is set up in only one location, however, the preliminary results indicate the application of suitable 1-minute rain attenuation model for specific site. The method provides useful information for microwave engineers and researchers in making decision over the choice of most suitable rain attenuation prediction in terrestrial links.

• Journal of The Korean Digital Architecture Interior Association
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• v.11 no.2
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• pp.21-30
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• 2011

Urban scape of Gyeongju is overlapped by periods. So, a study of each Periodical urban scape is required to understanding the present urban scape. All it requires study is on account of different a characteristic and the meaning of the scape. Especially, unified Silla period was most flourished in all time, has Abundant image of urban scape, heavily influences present urban scape. The research was proceeded through the classifying the concept of Urban form and the basic ideology and adopting the representative landscape at that time with the literatures and maps, on Unified Silla Period. And then tried to find out the identity of landscape with the link between the concepts of the representative landscape and that of Urban form in chronological order. The identity of historical landscape in Gyeongju on Unified Silla Period from the result of research has been influenced on by the connection with natural environment, urban form revealed by grid, space organized by vigorously heading up the inside, and Buddhistic ideology and esthetics.

• Animal cells and systems
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• v.13 no.2
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• pp.119-125
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• 2009

Mammalian hibernation is a type of natural adaptation that allows organisms to avoid harsh environment and to increase the possibility of survival. To investigate the molecular link between circadian and hibernating rhythms in the greater tube-nosed bats, Murina leucogaster, we set out to identify circadian genes that are expressed in bats, with specific focus on the PAS domain by using PCR-based screens. We could isolate a eDNA clone, designated as LPAS1, that encodes a protein of 521 amino acid residues. LPAS1 is closely related with CLOCK family with the highest homology to human CLOCK. Based on RT-PCR analyses, LPAS1 transcripts are ubiquitously present in tissues from both summer active and winter dormant periods. Given that LPAS1 is a member of the bHLH-PAS protein superfamily but lacks polyglutamine transactivation domains, it is likely to function as a repressor for endogenous CLOCK to hinder its roles in promoting transcription. Our result will open a new avenue to further examine the functional interconnection between the circadian clock and the circannual clock such as mammalian hibernation.

• Journal of Communications and Networks
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• v.7 no.2
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• pp.126-134
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• 2005

Reducing energy consumption in mobile hosts (MHs) is one of the most critical issues in wireles/mobile networks. IP paging protocol at network layer and power saving mechanism (PSM) at link layer are two core technologies to reduce the energy consumption of MHs. First, we investigate the energy efficiency of the current IEEE 802.11 power saving mechanism (PSM) when IP paging protocol is deployed over IEEE 802.11 networks. The result reveal that the current IEEE 802.11 PSM with a fixed wakeup interval (i.e., the static PSM) exhibits a degraded performance when it is integrated with IP paging protocol. Therefore, we propose an adaptive power saving mechanism in IEEE 802.11-based wireless IP networks. Unlike the static PSM, the adaptive PSM adjusts the wake-up interval adaptively depending on the session activity at IP layer. Specifically, the MH estimates the idle periods for incoming sessions based on the exponentially weighted moving average (EWMA) scheme and sets its wake-up interval dynamically by considering the estimated idle period and paging delay bound. For performance evaluation, we have conducted comprehensive simulations and compared the total cost and energy consumption, which are incurred in IP paging protocol in conjunction with various power saving mechanisms: The static PSM, the adaptive PSM, and the optimum PSM. Simulation results show that the adaptive PSM provides a closer performance to the optimum PSM than the static PSM.

• Journal of Communications and Networks
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• v.9 no.4
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• pp.490-498
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• 2007

BGP route flap damping(RFD) was anecdotally considered to be a key contributor to the stability of the global Internet inter-domain routing system. However, it was recently shown that RFD can incorrectly suppress for substantially long periods of time relatively stable routes, i.e., routes that only fail occasionally. This phenomenon can be attributed to the complex interaction between BGP path exploration and how the RFD algorithm identifies route flaps. In this paper we identify a distinct characteristic of BGP path exploration following a single network event such as a link or router failure. Based on this characteristic, we distinguish BGP route updates during BGP path exploration from route flaps and propose a novel BGP route flap damping algorithm, RFD+. RFD+ has a number of attractive properties in improving Internet routing stability. In particular, it can correctly suppress persistent route flaps without affecting routes that only fail occasionally. In addition to presenting the new algorithm and analyzing its properties, we also perform simulation studies to illustrate the performance of the algorithm.

• Proceedings of the KSRS Conference
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• v.1
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• pp.376-379
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• 2006

A numerous oil slicks of natural origin were revealed in the southwest (SW) part of Caspian Sea by the synthetic aperture radar (SAR) images acquired by Envisat satellite in 2003-2004. On the basis of computer processing, visual analysis of SAR images and comparisons with bathymetry, geophysical and seismic data in geographic information system (GIS), a link between these slicks and unloading of liquid hydrocarbons in the SW Caspian is established. Oil slicks are basically concentrated above domes of local geological formations of the sedimentary cover. In total more than 90 seeps and mud volcanoes having a repeating regime and representing an active type were identified; they are distributed across the SW Azerbaijan and West Iranian sectors. Periodical occurrence of slicks can reflect alternation of mud volcanism pulses forced by intensive seismicity with the quiet periods. Seepage rate of oil in the SW part of the Caspian Sea according to SAR images is estimated to be up to 16,000 metric tons per year. The importance of unloading of oils on hydrochemistry and ecological conditions of the Caspian Sea is demonstrated. Conclusion is done that the Envisat SAR to be an excellent tool for studying oil seeps through observation oil slicks floating on the sea surface.

• International Journal of Advanced Culture Technology
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• v.11 no.2
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• pp.238-248
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• 2023

This study aims to examine the symbolism of the emblems of World Expositions by using Victor Turner's symbolic theory as a research method, and to reveal the symbolic types behind them by classifying the emblem designs of different periods and themes. The research object is 12 comprehensive World's Fair emblems from the 1939 New York World's Fair in the United States to the 2025 Osaka World's Fair in Japan, as identified by Bureau International des Expositions. The research method mainly adopts documentary research to collect historical information and theoretical frameworks related to the design of World's Fair emblems. In the analysis process, Victor Turner's symbolic sign theory is used as the main analytical framework to link the design elements of emblems to their relevance to specific societies and cultures in order to reveal the themes, values and ideas represented by the emblem symbolism. The results of the study show that the design of the Expo emblem uses different symbols, including material symbols, behavioral symbols, sensory symbols, natural symbols, social symbols and virtual symbols, to convey the core concepts, themes and values of the Expo. Through different types of symbols, the Expo emblem shows a wide range of concerns about technology and the future, mankind and the world, nature and ecology, and society and innovation. The symbolic design of the emblem plays an important role in conveying the core concept and theme of the Expo.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.4
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• pp.85-101
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• 2013

The primary goal of this research is to link two currently disconnected literature; the history of urban redevelopment and the one of urban parks and open spaces in the United States (US). Through this exercise, this study attempts to reveal examples of urban parks and open spaces that have yielded economic effects, and emphasize their possibility as a measure of urban redevelopment. Five phases are presented, starting with two Pre-World War II urbanization periods, and three subsequent periods of Post-World War II urban redevelopment (1940s~1960s, late 1960s~1970s, 1980s~present). While urban parks in the 19th century urbanization period held a preeminent place in urban design, policy and economy, ensuing depression and World War II diminished their role as a channel to ease unemployment. In the first phase of urban redevelopment, the economic motive to build open space was to boost the appeal of specific locales in order to draw people and businesses back to a neglected city. In the second phase, public effort to create and maintain urban parks and open spaces declined due to the budget austerity, instead, community open spaces flourished through the voluntary actions and helped neighborhoods to regain desirability. In the third phase, the aspirations and functions of such projects resemble their forerunners of the first phase, but their targets extended to global businesses and elites.