• Tunnel and Underground Space
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• v.21 no.1
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• pp.11-19
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• 2011

Geothermal energy is believed to be an important source among the renewable energy sources to provide the base load electricity. Although there has been a drastic increase in the use of geothermal heat pump in Korea, there is no geothermal power plant in operation in Korea. Fortunately, the first EGS (Enhanced Geothermal System) Project in Korea has started in Dec 2010. This five year project is divided into two stages; two years for exploration and drilling of 3 km depth to confirm the minimum target temperature of 100 degrees, and another three years composed drilling 5 km doublet, hydraulic stimulation of geothermal reservoir with expected temperature of 180 degrees (40 kg/s) and construction of MW geothermal power plant in the surface. This EGS project would be a landmark effort that invited a consortium of industry, research institutes and university with expertises in the fields of geology, hydrogeology, geophysics, geomechanics and plant engineering.

• Horticultural Science & Technology
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• v.31 no.5
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• pp.652-655
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• 2013

Natural habitats of weedy melons were distributed on the islands along and on the west and south coasts of Korean peninsula including Boryeong, Seosan (Taean), Seocheon, Okgu, Buan, Gochang, Yeonggwang, Muan, Shinan, Haenam, Jindo, Wando, Goheung, Yeocheon, Hadong, Namhae, Goseong, Tongyeong, Geoje, and Jeju islands including Jeju city, Bukjeju-gun and Nam Jeju-gun. Weedy melons were found growing wildly in or around the cultivated lands in these regions. Natural habitats of weedy melons were in and around the cultivated lands. Weedy melon plants were found most often in soybean fields, followed by fields of mungbean, sweet potato, pepper, sesame, cotton, and peanuts. The plants were also found growing wild in foxtail millet fields, rice paddy levees along the streams, upland field edges, watermelon fields, corn fields, vegetable gardens near farmhouse, orange fields, compost piles, fallow fields, roadside and home gardens. They inhabited in sunny and a little dry spaces in relatively low-height crop plant fields in general. The time of fruit maturity was from early July to late October with the most frequency in September according to post survey answer. Fruits dropped off from the fruit stalk when matured. This phenomenon was thought beneficial for perpetuation in the wild. The fruits were being used commonly for food and toys for children. It was thought that weedy melons were perpetuating through the cycle of human and animal feeding of the fruits, human and animal droppings, often mixed in compost, and application of the compost to crop fields by human.

• Fire Science and Engineering
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• v.29 no.1
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• pp.38-44
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• 2015

This study suggested the problems and their improvement measures for the operation of fire detectors and sprinkler heads installed at apartment houses. According to a census on population and housing in 2010, apartment houses account for 71.6% of the total housing facilities. And by fire statistics data of the National Emergency Management Agency, approximately 25.0% of fire accidents and 46.4% of casualties occur at apartment houses every year. Therefore, this study conducted for identifying the causes and characteristics of fire to establish the fire safety improvement measures for apartment houses. And this study was carried out virtual fire simulation at domestic apartment houses. The scenario of the simulation contains a comparative analysis on the operation time of standard sprinkler heads and residential sprinkler heads, heat detectors and smoke detectors. As a result of simulation, it was found that standard sprinkler heads and heat detectors installed at the existing apartment houses should be replaced with residential sprinkler heads and smoke detectors for rapid fire suppression. In addition, sprinkler systems should be considered to be installed for excluded floor at apartment houses. Especially, it is necessary to construct remote inspect systems like advanced countries for efficiency of apartment houses safety management.

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.427-436
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• 2017

A fixed-precision-level sampling plan was developed to establish control of the two-spotted spider mite, Tetranychus urticae, in two strawberry greenhouses (conventional plot, natural enemy plot). T. urticae was sampled by taking a three-leaflet leaf (1 stalk) from each plant (3 three-leaflet leaves) from each sampling position. Each leaflet was divided into three different units (1-leaflet, 2-leaflet, and 3-leaflet units) to compare relative net precision (RNP) values for selection of the appropriate sampling unit. The relative net precision values indicated that a 1-leaflet unit was more precise and cost-efficient than other units. The spatial distribution analysis was performed using Taylor's power law (TPL). Homogeneity of the TPL parameters in each greenhouse was evaluated by using the analysis of covariance (ANCOVA). A fixed-precision-level sequential sampling plan was developed using the parameters of TPL generated from the combined data of the conventional plot and natural enemy plot in a 1-leaflet sampling unit. Sequential classification sampling plans were also developed using the action threshold of 3 and 10 mites for pooled data. Using the results obtained in the independent data, simulated validation of the developed sampling plan by Resampling validation for sampling plan (RVSP) indicated a reasonable level of precision.

• Journal of KIISE:Databases
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• v.33 no.1
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• pp.12-31
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• 2006

The n-gram inverted index has two major advantages: language-neutral and error-tolerant. Due to these advantages, it has been widely used in information retrieval or in similar sequence matching for DNA and Protein databases. Nevertheless, the n-gram inverted index also has drawbacks: the size tends to be very large, and the performance of queries tends to be bad. In this paper, we propose the two-level n-gram inverted index (simply, the n-gram/2L index) that significantly reduces the size and improves the query performance while preserving the advantages of the n-gram inverted index. The proposed index eliminates the redundancy of the position information that exists in the n-gram inverted index. The proposed index is constructed in two steps: 1) extracting subsequences of length m from documents and 2) extracting n-grams from those subsequences. We formally prove that this two-step construction is identical to the relational normalization process that removes the redundancy caused by a non-trivial multivalued dependency. The n-gram/2L index has excellent properties: 1) it significantly reduces the size and improves the Performance compared with the n-gram inverted index with these improvements becoming more marked as the database size gets larger; 2) the query processing time increases only very slightly as the query length gets longer. Experimental results using databases of 1 GBytes show that the size of the n-gram/2L index is reduced by up to 1.9${\~}$2.7 times and, at the same time, the query performance is improved by up to 13.1 times compared with those of the n-gram inverted index.

• The KIPS Transactions:PartD
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• v.16D no.1
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• pp.1-10
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• 2009

One of major purposes of a RFID system is to track moving objects using tags attached to the objects. Because a tagged object has both location and time information expressed as the location of the reader, we can index the trajectory of the object like existing spatiotemporal objects. More efficient tracking may be possible if a spatiotemporal trajectory can be formed of a tag, but there has not been much research on tag trajectory indexes. A characteristic that distinguishes tags from existing spatiotemporal objects is that a tag creates a separate trajectory in each reader by entering and then leaving the reader. As a result, there is a trajectory interruption interval between readers, in which the tag cannot be located, and this makes it difficult to track the tag. In addition, the point tags that only enter and don't leave readers do not create trajectories, so cannot be tracked. To solve this problem, we propose a tag trajectory index called TR-tree (tag trajectory R-tree in RFID system) that can track a tag by combining separate trajectories among readers into one trajectory. The results show that TR-tree, which overcomes the trajectory interruption superior performance than TPIR-tree and R-tree.

• Journal of Korean Society of Forest Science
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• v.89 no.5
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• pp.576-584
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• 2000

The term 'greenways' is a fairly new one. The term greenways refer to linear corridors which set aside pieces of nature. The objective of this study was to find out the feasibility of developing greenways in Taegu. Sample of 446 trail users were asked to describe their use patterns and as well as their perceptions of the benefits and problems associated with trails through on-site interviews conducted during the months of July and August of 1999. Trail users in Taegu were predominately male(61%) and over half of the respondents used private vehicle to access to the study areas as compared to 2% of respondents used bicycle. Trail users responded that health & fitness and open space preservation were the two most important benefits, and the provision of trail access to disabled persons was ranked last. As problems at study areas, lack of interpretive information was the biggest problem followed by lack of drinking water, poor trail marking/signs and not enough information. Most(94.1%) of the trail users surveyed indicated that they would support greenways development and 96.8% of respondent would use after greenways development. Willingness to pay for developing greenways was assessed with hypothetical scenario. Average willingness to pay in the survey was 10,200 won as a tax. The development/application of greenways in Taegu would work best when establish a network of trails with environmentally sensitive manner.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.2
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• pp.36-49
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• 2016

A subway system is one of the major transportation modes at a metropolitan area. When it meets the other lines, the metro station, so-called transferring station, is usually threatened by severe pedestrian congestion and safety issue of transit users including the transportation vulnerable. Although transportation planners forecast travel demand at the beginning, it is not easy to predict pedestrian flows precisely for a long term if land use plans have dramatically changed. Due to expensive costs, structural extension of metro stations is limited. Therefore, it requires efficient and technical improvements as meeting the demand of pedestrian and physical characteristics. In this study, the core mechanism of pedestrian movement-based simulation model was introduced and evacuation scenarios were analyzed with the developed model. As a result, the multiple optimal routes for unexpected events at the solid space of the multiple stories are easily searched through the simulator and in the case of Sadang Station, travel time can be reduced by 60% when the evacuation information and intuitive design are provided.

• Korean Journal of Remote Sensing
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• v.13 no.1
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• pp.13-30
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• 1997

Recent improvements of satellite remote sensing sensors which are represented by hyperspectral imaging sensors and high spatial resolution sensors provide a large amount of data, typically several hundred megabytes per one scene. Moreover, increasing information exchange via internet and information super-highway requires the developments of more active service systems for processing and analysing of remote sensing data in order to provide value-added products. In this sense, an advanced satellite data processing system is being developed to achive high performance in computing speed and efficieney in processing a huge volume of data, and to make possible network computing and easy improving, upgrading and managing of systems. JAVA internet programming language provides several advantages for developing software such as object-oriented programming, multi-threading and robust memory managent. Using these features, a satellite data processing system named as GeoPixel has been developing using JAVA language. The GeoPixel adopted newly developed techniques including object-pipe connect method between each process and multi-threading structure. In other words, this system has characteristics such as independent operating platform and efficient data processing by handling a huge volume of remote sensing data with robustness. In the evaluation of data processing capability, the satisfactory results were shown in utilizing computer resources(CPU and Memory) and processing speeds.

• (The)Korea Educational Review
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• v.14 no.2
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• pp.155-179
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• 2008

The objective of this study was to analyze the satisfaction of graduate students participating in the Brain Korea21 (BK21) project in five supporting areas of the project: curriculum, job searching and career development, academic development, the globalization of education, and educational environment. A further objective was to find efficient methods of providing students with stable academic and financial support for their research in order to develop them as distinguished researchers. In order to answer research questions, this study conducted a survey of the BK21 project satisfaction with students majoring in humanities or social sciences and analyzed the survey results. The tool has 7 dimensions: 'curriculum', 'job searching and career development', 'stable support for academic development', 'support for academic activities out of school', 'globalization of education', 'lectures in English', and 'educational environment'. The survey found that survey participants were in general satisfied with the BK21 project. Of these 7 dimensions, the results showed remarkably high satisfaction dimensions for 'stable support for academic development' and 'support for academic activities out of school' while indicating a comparatively low satisfaction for 'job searching and career development'. The result and analysis of this study suggests that the BK21 project needs to emphasize the following: PR for the project, provide opportunities for the training for career development and job information to students, modify the areas of academic support, remodel programs of short- and long-term studies in foreign countries, improve the educational service system for lectures in English, and secure research facilities.