• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.303-308
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• 2014

Reclaimed lands, expected as high-tech export horticultural complex, have unusual light environments due to sea fog. For adequate greenhouse design at reclaimed land, spatial light distributions in greenhouse should be required considering diffusive and direct lights. The objectives of this study were to analyze light environments and estimate spatial light distributions in greenhouse at reclaimed land by 3D greenhouse models. Total and diffusive lights were compared between reclaimed land and inland. For verification of the 3D greenhouse models, spatial light distributions and measured light intensities in greenhouse were compared with the estimated ones. Light environments at reclaimed land showed a higher diffusive irradiation than at inland, especially near sunrise and sunset. The estimated spatial light distributions in greenhouse showed good agreements with the measured ones. By using this method, we could estimate the average light intensity with time and spatial light distributions in greenhouse at specific outside light conditions. This result will be useful for analysis of light environments but also estimation of crop light inception in greenhouse at reclaimed land.

• Journal of the Korean association of regional geographers
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• v.19 no.4
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• pp.615-626
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• 2013

In this study, spatial patterns of the urban flood vulnerability index in Seoul are examined by considering climate exposure, sensitivity, and adaptability associated with floodings for recent 5 year (2006~2010) period by the smallest administrative unit called Dong. According to the results of correlation analyses based on the IPCC(Intergovernmental Panel on Climate Change)'s vulnerability model, among many variables associated with urban flooding, rainwater tank capacity, 1-day maximum precipitation and flood pumping station capacity have statistically-significant, and relatively-high correlations with the number of flood damage in Seoul. The flood vulnerability map demonstrates that the extensive areas along Anyang and Joongnang streams show relatively high flood vulnerability in Seoul due to high sensitivity. Especially in case of Joongnang stream areas, climatic factors also contribute to the increase of flood vulnerability. At local scales, several Dong areas in Gangdong-gu and Songpa-gu also show high flood vulnerability due to low adaptability, while those in Gangnam-gu do due to high sensibility and climate factor such as extreme rainfall events. These results derived from the flood vulnerability map by Dong unit can be utilized as primary data in establishing the adaptation, management and proactive policies for flooding prevention within the urban areas in more detail.

• Journal of the Korean Society for Railway
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• v.15 no.4
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• pp.402-407
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• 2012

Since reports on trip delays or incidents often appear as accident articles on the press, the social criticisms and concerns on the safety of the urban railway are increasing. Therefore, a railway authority sometimes adopts an abstract safety goal like "let's build the urban railway to a masterpiece level" or "let's obtain an aeronautic safety level" to make citizens relieved and to alert involved persons. However with a vague goal, it is almost impossible to make an implementation plan systematic which helps the authority academically verify and validate if the goal is achieved or not. In this paper, the features of the railway safety are described and the safety models for securing the safety of the urban railway are surveyed and categorized. Based on the comparisons among the features and limitations of the models, we identify a more practical model which can be applied to the urban railway more effectively.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.5
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• pp.1373-1382
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• 2014

This paper presents a hydraulic performance graph model in which the flow carrying capacity of a channel system was determined by accounting the interacting backwater effect among channel reaches and incoming lateral flow. The method utilizes hydraulic performance graphs (HPGs), and the method is applied to a natural channel Nakdong River to examine its applicability. This research shows that estimation results using HPG are close to records from the stage station and the results from a widely-accepted model, HEC-RAS. Assuming that a water level gage site is ungaged, water level estimations by HPGs compared with observation show that with a flood event, the HPGs underestimate in the water level ascension phase, but in the recession phase they overestimate results. The accuracy of estimation with HPGs was greatly improved by considering the time difference of flooding between the observation and estimation locations.

• Journal of Korean Society of Forest Science
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• v.86 no.2
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• pp.200-207
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• 1997

The throughfall, stemflow and precipitation interception during the period of May to November 1995 were compared between three stands of Pinus koraiensis, Larix leptolepis and Quercus species stand growing at Kwangju-Gun, Kyunggi-Do. The total amount of precipitation during the period in the study area was 1,821mm, higher than average precipitation. The amount of interception showed 21.8% of the total precipitation in Quercus stand, whereas 15.7 and 19.4 in P. koraiensis and L. leptolepis stands, respectively. Precipitation leached on forest floor was occupied mainly by throughfall for all the stands, and it was specially higher in P. koraiensis stand. The amount of stemflow was appeared higher in Quercus stand(5.0%) than P. koraiensis stand(1.1%) or L. leptolepis stand(1.1%). The relationship between throughfall or stemflow and total precipitation in all the stands were highly significant.

• Journal of Korean Society of Forest Science
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• v.90 no.4
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• pp.488-494
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• 2001

This study was conducted to investigate forest ecosystem assessment which were widely used in Germany and Austria. The study area, Mt. Teawha, is located at Kwangju, Kyunggi-Do province. The methodology of this study considered the following factors. First forest types were classified accoding to species composition and age of tree layer. Naturalness, diversity and rerenees of each forest type were classified into 5 level. Finally, the forest types were assessed by synthesizing those 3 factors. Qurecus mongolica- and valley forest type over 300m was classified as naturalness 4 and Qurecus accustima, Quercus accusitima and Q. variabilis were as naturalness 3. The plantation types on the lower slope showed the level of naturlness 1 or 2. Diversity was similer to naturalness. But indices were different from each other. In the case of Larix leptolepsis plantations, naturalness indicated 1, while diversity showed 3. The valley forest type, wet forest and forest edge were classified into rare forest type. It was concluded that this method could be more efficient method comparing with existing method for assessment of naturality and thereby could contribute for biodiversity conservation in Korea.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.8
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• pp.942-949
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• 2016

Efficient routing protocols designed for Wireless Sensor Networks (WSN) can be extended and applied to Internet of Things (IoT) data routing, as IoT can be considered to be an extension from WSN. When the size of the data in IoT is often bigger than in conventional WSNs, existing cluster routing protocol such as LEACH may cause high data loss rate due to its incomplete load balancing. We present an enhanced LEACH-based protocol which can minimize the data loss which is an important performance measure in IoT. In our proposed protocol, the base station estimates the location of nodes by the trilateration technique to make sure optimal number of cluster heads and members in a deterministic manner. We evaluate our proposed protocol via computer simulations in terms of data loss rate and average network lifetime.

• Journal of Korea Water Resources Association
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• v.33 no.6
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• pp.765-774
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• 2000

The purpose of this study are to develop a realistic methodology to estimate agricultural water supply for rice paddy fields from reservoirs, pumping stations, intake structures, and tube wells on river basin scale. Agricultural water supply from irrigation reservoirs are estimated using the daily or ten day's storage rate data and DIROMmaily Inigation Reservoir Operation Model) model. Estimation of daily water supply from pumping station are carried out from the annual water use with typical water supply patterns. The daily groundwater withdrawn are investigated from the gross water requirement for rice and the design capacity of tube well. And, the daily intake discharge are estimated the minimum amount from the gross water requirement, stream discharge, and the design capacity. During 1993 to 1997, the annual water supply for irrigation in the Han river basin ranged from 569 to 709 million $\textrm{m}^3/yr$, and the mean was estimated to be 640 million $\textrm{m}^3/yr$.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.3
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• pp.457-465
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• 2018

This study proposes a novel approach to explore a "travel time budget (TTB)" using a mobile phone signaling data (MPSD), which are passively generated between a mobile phone and a base station. The data analyzied in this study were provided from KT for 8 days (from May 19 to 26 in 2016). They were about 45 million signals passively generated from users whose stay area during night was classified as three areas in Mapo-gu, Seoul and in the city of Sejong. The estmation of TTB was implemented with various pre-processing techniques on the MPSD data in a data-driven analysis. As a result, the TTBs of Mapo-gu, Seoul and Sejong were 82.94 and 80.70 minutes, respectively. The results in this study were also compared with those based on the traditional methods. The authors expect that this result will help transport experts improve the use of MPSD.

• Journal of Korean Society of Transportation
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• v.28 no.6
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• pp.121-131
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• 2010

To effectively reduce PM10 generated in concourses and platforms of subway stations, a research is being conducted to find the PM10 source. The main source of PM10 in subway stations was PM10 generated in the main line tunnels, which was generated in proportion to the frequency of the train operation. Each amount of the PM10 generated when the train was operated once, was constant regardless of the time. On the assumption that the PM10 level in a tunnel of a line is a sum of newly generated amount of dust when the subway passes and the amount carried from the adjacent stations by the wind generated from the subway rolling stocks, the method which estimates the intensive PM10 occurring section was developed and applied to the 12 stations between Cheongdam and Jangseungbaegi in Seoul Subway Line 7.