• Journal of Korean Society of Water and Wastewater
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• v.27 no.1
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• pp.1-10
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• 2013

Major issues in water supply service have changed from expansion of service area to improvement of service quality, i.e., water quality and safety, and early response to emergency situation. This change in the service concept triggers the perceptions of limitation with the current centralized water supply system and of necessities of decentralized (distributed) water supply system (DWSS), which can make up the limitations. DWSS can reduce the possibility of water supply outage by establishing multiple barriers such as emergency water supply system, and secure better water quality by locating treatment facilities neighboring consumers. On the other hand, fluctuation of water demand will be increased due to the reduced supply area, which makes difficult to promptly respond the fluctuating demand. In order to supplement this, hybrid water supply system was proposed, which combined DWSS with conventional water supply system using distributing reservoir to secure the stability of water supply. The Optimal connection point of DWSS to existing water supply network in urban area was determined by simulating a supply network using EPANET. Optimal location of decentralized water treatment plant (or connection point) is a nodal point where changes in pressure at other nodal points can be minimized. At the same time, the optimal point should be selected to minimize hydraulic retention time in supply network (water age) to secure proper water quality. In order to locate the point where these two criteria are satisfied optimally, Distance measure method, one of multi-criteria decision making was employed to integrate the two results having different dimensions. This methodology can be used as an efficient decision-support criterion for the location of treatment plant in decentralized water supply system.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.3
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• pp.87-92
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• 2005

The permeability of concrete affects largely on the durability of concrete, therefore it is required that the correct assessment and improvement of permeability. Therefore it is rational method that the permeability of concrete structures is estimated in the common use states under loading than in the early sound conditions. In this study, to improve the permeable efficiency of concrete, some kinds of fiber and resin are mixed in making of concrete specimens. And also, for the reasonable assessment of permeability, after 50% and 70% pre-loadings of its compressive strength were acted on the specimens, the tests were executed. From the results of this study, in the case of 50% pre-loading coefficients of permeability were increased about 1.4times against the nonpre-loading specimens and in the case of 70% pre-loading they were increased about 17.8times. And it turned out that hybrid steel fiber reinforcement is most effective for the improvement of permeable efficiency of concrete.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.3
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• pp.302-309
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• 2020

Early-detection and monitoring of toxic chemical gas cloud with chemical detector is essential for reducing the number of casualties. Conventional method for chemical detection and reconnaissance has the limitation in approaching to chemically contaminated site and prompt understanding for the situation. Stand-off detector can detect and identify the chemical gas at a long distance but it cannot know exact distance and position. Chemical detection UAV is an emerging platform for its high mobility and operation safety. In this study, we have conducted chemical gas cloud detection with the stand-off chemical detector and the chemical detection UAV. DMMP vapor was generated in the area where the cloud can be detected through the field of view(FOV) of stand-off chemical detector. Monitoring the vapor cloud with standoff detector, the chemical detection UAV moved back and forth at the area DMMP vapor being generated to detect the chemical contamination. The hybrid detection system with standoff cloud detection and point detection by chemical sensors with UAV seems to be very efficient as a new concept of chemical detection.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.294-299
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• 2004

An assessment of a novel laser-electric hybrid propulsion system was conducted, in which a laser-induced plasma was induced through laser beam irradiation onto a solid target and accelerated by electrical means instead of direct acceleration only by using a laser beam. A fundamental study of newly developed rectangular laser-assisted pulsed-plasma thruster (PPT) was conducted. On discharge characteristics and thrust performances with increased peak current compared to our previous study to increase effects of electromagnetic forces on plasma acceleration. Maximum peak current increased for our early study by increasing electromagnetic effects in a laser assisted PPT. At 8.65 J discharge energy, the maximum current reached about 8000 A. Plasma behaviors emitted from a thruster in various cases were observed with an ICCD camera. It was shown that the plasma behaviors were almost identical between low and high voltage cases in initial several hundred nanoseconds, however, plasma emission with longer duration was observed in higher voltage cases. Canted current sheet structures were also observed in the higher voltage cases using a larger capacitor. With a newly developed torsion-balance type thrust stand, thrust performances of laser assisted PPT could be estimated. The impulse bit and specific impulse linearly increased. On the other hand, coupling coefficient and the thrust efficiency did not increase linearly. The coupling coefficient decreased with energy showing maximum value (20.8 ？Nsec/J) at 0 J, or in a pure laser ablation cases. Thrust efficiency first decreased with energy from 0 to 1.4 J and then increased linearly with energy from 1.4 J to 8.6 J. At 8.65 J operation, impulse bit of 38.1 ？Nsec, specific impulse of 3791 sec, thrust efficiency of 8 %, and coupling coefficient of 4.3 ？Nsec/J were obtained.

• Radiation Oncology Journal
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• v.4 no.2
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• pp.107-113
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• 1986

Radiation myelitis is a rather rare, but irreversible fatal complication. Etiology, pathologic change, clinical symptoms and the method of diagnosis have been studied with animal experiments and human necropsies. In spite of massive studies, pathogenesis of post-irradiation myelitis and the level of tolerance dose still remain controversial. Thoracolumbar spine of 110 hybrid mice were irradiated with orthovoltage x-ray machine. Mild capillary congestion and axonal swelling were observed in 1,000 rad irradiated specimens. Focal necrosis in 3,500 rad specimens, fragmentation of neural tissue in 4,000 rad specimens were also observed. These results suggest that 5,000 rad is not a completely safe tolerable dose which have been accepted and we cannot exclude direct radiation damage to news tissue as the causative pathology of radiation myelitis in addition to blood vessel damage.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.377-384
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• 2009

Three-year-old seedlings of susceptible Pinus densiflora and resistant Pinus x rigitaeda were each inoculated with the pinewood nematode, Bursaphelenchus xylophilus, to compare disease development. Needle dehydration was evident on seedlings of P. densiflora by 20 days after inoculation, 10 days earlier than this symptom was observed on P. ${\times}$ rigitaeda. Xylem drying was more frequent in seedlings of P. densiflora than in that of P. ${\times}$ rigitaeda between 20 and 60 days after inoculation. No significant differences were found between P. densiflora and P. ${\times}$ rigitaeda for stem water content or for stem and leaf relative water content in current-year branches after nematode inoculation, but the average number of B. xylophilus recovered from stems differed significantly between the two groups. The number of B. xylophilus recovered from stems was negatively correlated with the stem water content and with stem and leaf relative water content. By the time the experiment was terminated at 60 days after inoculation, all 3 of the last group of P. densiflora seedlings had died, but 2 of the 3 remaining P. ${\times}$ rigitaeda hybrid seedlings were still alive. Additional studies are needed to further explore the specific mechanisms preventing nematode multiplication in the seedlings of resistant P. ${\times}$ rigitaeda.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.11
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• pp.5568-5587
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• 2018

This research uses artificial intelligence methods for computer network intrusion detection system modeling. Primary classification is done using self-organized maps (SOM) in two levels, while the secondary classification of ambiguous data is done using Sugeno type Fuzzy Inference System (FIS). FIS is created by using Adaptive Neuro-Fuzzy Inference System (ANFIS). The main challenge for this system was to successfully detect attacks that are either unknown or that are represented by very small percentage of samples in training dataset. Improved algorithm for SOMs in second layer and for the FIS creation is developed for this purpose. Number of clusters in the second SOM layer is optimized by using our improved algorithm to minimize amount of ambiguous data forwarded to FIS. FIS is created using ANFIS that was built on ambiguous training dataset clustered by another SOM (which size is determined dynamically). Proposed hybrid model is created and tested using NSL KDD dataset. For our research, NSL KDD is especially interesting in terms of class distribution (overlapping). Objectives of this research were: to successfully detect intrusions represented in data with small percentage of the total traffic during early detection stages, to successfully deal with overlapping data (separate ambiguous data), to maximize detection rate (DR) and minimize false alarm rate (FAR). Proposed hybrid model with test data achieved acceptable DR value 0.8883 and FAR value 0.2415. The objectives were successfully achieved as it is presented (compared with the similar researches on NSL KDD dataset). Proposed model can be used not only in further research related to this domain, but also in other research areas.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.1
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• pp.76-84
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• 2022

Arrhythmia is a condition in which the heart beats abnormally or irregularly, early detection is very important because it can cause dangerous situations such as fainting or sudden cardiac death. However, performance degradation occurs due to personalized differences in ECG signals. In this paper, we propose arrhythmia classification using hybrid combination model of CNN-LSTM. For this purpose, the R wave is detected from noise removed signal and a single bit segment was extracted. It consisted of eight convolutional layers to extract the features of the arrhythmia in detail, used them as the input of the LSTM. The weights were learned through deep learning and the model was evaluated by the verification data. The performance was compared in terms of the accuracy, precision, recall, F1 score through MIT-BIH arrhythmia database. The achieved scores indicate 92.3%, 90.98%, 92.20%, 90.72% in terms of the accuracy, precision, recall, F1 score, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.2
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• pp.177-186
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• 1997

A field experiment was conducted to evaluate growth characteristics, dry matter yield and crude protein yield according to different planting dates at sorghum $\times$ sudangrass hybrid(SSH) and soybean intercropping. Planting dates were five treatment of may 6(Tl), may 13(T2), may 20(T3), may 27(T4) and june 3(T5), and cutting frequency was two times a year. 1. Plant length of SSH was the highest at T2 as 253cm, but T5 was the shortest as 203cm. In the soybean, T3 and T4 were the highest as 113cm, respectively. Leaf length of SSH was high at T5. In the soybean, T2 was the highest as 17cm. Average leaf width of T2, T3 and T4 was higher than TI and T5. 2. Leaf number of T3(SSH and soybean) was higher than other treatments, Stem diameter of SSH and soybean showed the highest as 12.3mm and 8.6mrn at T5 and T3, respectively. In the SSY mean stem hardness of TI was the highest as 2.5kg/$cm^2$, but soybean was the highest at T1(8.0kg/$cm^2$) 3. Deed stubble according to move seeding date of SSH were 11.4 percentage at TI, and 3.9 percentage at T5 treatment. 4. Total dry matter yield according to move seeding date was the highest at T3 as 20,937kghq but T5 of late seeding was the lowest as 16,04Okgha(P < 0.05). 5. In the first cutting time, protein content of SSH was the highest at T3 as 9.9 percentage, but T1 was the lowest as 8.4 percentage. In the 2nd cutting, T5 was the highest as 8.7% but T1 was the lowest as 6.2%. In the soybean, T5 was the highest as 19.4% but TI of early seeding was the lowest as 16.2 percentage. Crude protein yield was the highest at T3 as 2,233.5kghq but TI of early seeding was the lowest as 1,579.7kgha (P < 0.05). As mentioned above the results, T2(may 13), T3(may 20) and T4(may 27) treatment could be recommended as the best suitable seeding date when drymatter and protein yield were considered.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.14
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• pp.87-90
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• 1973

Optimum plot shape and size in a uniformity trial in the newly founded experimental farm of KAERI were determined for seed yield with the basic units consisted of 2.5m $\times$ 0.6m plot. Various plot sizes and shapes were made by combination of the basic units. Coefficients of variations for yield were 21% in local branch type variety Kumkang-Dairip and 20% in the introduced branchless type variety Clark. This result indicates that the field in the new experimental farm is appropriate for soybean yield trials when adequate number of replications are employed in the field experiment. In general, C. V. values were gradually decreased with increase of plot sizes. Although the data were not consistant, the errors for the long narrow plots tend to have somewhat smaller than for the square shape plots. A sharp decrease in C.V. value was found from the $4.5\textrm{m}^2$ plot in the variety Kumkang-Dairip and from the $6\textrm{m}^2$ plot in the variety Clark. These results imply that 5-$6\textrm{m}^2$ plot could be used for yield trials in early generations of hybrid progenies. 2.5-5m long plot with 3-4 replications will be practical for yield trials in the early hybrid generations. The C.V. values with 7.5m long plot was about 16% in both varieties and 15.3% in 10m plot. These results indicate that 7.5-10m plot with 3-4 replications could be employed in accurate yield test in the advanced generations.