• Journal of Communications and Networks
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• v.14 no.2
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• pp.162-168
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• 2012

This paper considers the scenario in which a set of nodes share a common channel. Some nodes have a rechargeable battery and the others are plugged to a reliable power supply and, thus, have no energy limitations. We consider two source-destination pairs and apply the concept of cognitive radio communication in sharing the common channel. Specifically, we give high-priority to the energy-constrained source-destination pair, i.e., primary pair, and low-priority to the pair which is free from such constraint, i.e., secondary pair. In contrast to the traditional notion of cognitive radio, in which the secondary transmitter is required to relinquish the channel as soon as the primary is detected, the secondary transmitter not only utilizes the idle slots of primary pair but also transmits along with the primary transmitter with probability p. This is possible because we consider the general multi-packet reception model. Given the requirement on the primary pair's throughput, the probability p is chosen to maximize the secondary pair's throughput. To this end, we obtain two-dimensional maximum stable throughput region which describes the theoretical limit on rates that we can push into the network while maintaining the queues in the network to be stable. The result is obtained for both cases in which the capacity of the battery at the primary node is infinite and also finite.

• Journal of Digital Contents Society
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• v.12 no.3
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• pp.279-289
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• 2011

The latest hardware and software techniques are combined to give safe walking guidance and convenient service of realtime walking assistance system for visually impaired person. This system consists of obstacle detection and perception, place recognition, and sign recognition for pedestrian can safely walking to arrive at their destination. In this paper, we exploit the sign object detection system in subway station for sign recognition that one of the important factors of walking assistance system. This paper suggest the adaptive feature map that can be robustly extract the sign object region from complexed environment with light and noise. And recognize a sign using fast zernike moment features which is invariant under translation, rotation and scale of object during walking. We considered three types of signs as arrow, restroom, and exit number and perform the training and recognizing steps through adaboost classifier. The experimental results prove that our method can be suitable and stable for real-time system through yields on the average 87.16% stable detection rate and 20 frame/sec of operation time for three types of signs in 5000 images of sign database.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.384-388
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• 2013

Fluorine-doping on the $Li_{1+x}Mn_{1.9-x}Al_{0.1}O_4$ spinel cathode materials is found to alter crystal shape, and enhance initial interfacial reactivity and solid electrolyte interphase (SEI) formation, leading to improved initial coulombic efficiency in the voltage region of 3.3-4.3 V vs. Li/$Li^+$ in the room temperature electrolyte of 1 M $LiPF_6$/EC:EMC. SEM imaging reveals that the facetting on higher surface energy plane of (101) is additionally developed at the edges of an octahedron that is predominantly grown with the most thermodynamically stable (111) plane, which enhances interfacial reactivity. Fluorine-doping also increases the amount of interfacially reactive $Mn^{3+}$ on both bulk and surface for charge neutrality. Enhanced interfacial reactivity by fluorine-doping attributes instant formation of a stable SEI layer and improved initial cyclic efficiency. The data contribute to a basic understanding of the impacts of composition on material properties and cycling behavior of spinel-based cathode materials for lithium-ion batteries.

• Journal of Microbiology
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• v.40 no.2
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• pp.140-145
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• 2002

The 5.8 kb pMMH1, rolling-circle replication (RCR) plasmid of the wild type soil Bacillus mesentericus was developed into a novel secretion vector system in Bacillus subtilis. The pMMHl turned out to have a replication origin and two open reading frames (ORFs) of the putative γ-GTP and type I signal peptidase (sipP). To characterize the regions necessary for plasmid stability and high copy number, five vectors (pPS, pPP, pEN, pMN, pME) were constructed by disruption or deletion of each region in pMMH1. Like pMMHl all constructed vectors were stable over 100 generations In a non-selective medium. Since pPS was the smallest (2.3 kb)of all, it was selected for the construction of a navel secretion vector, Using the $\alpha$-amylase promoter/signal sequence of B. subtilils the novel plasmid pJSN was constructed. When $\beta$-glucosidase was expressed using pJSN, we found $\beta$-glucosidase activity in the medium. This result strongly suggested that plasmid pJSN can be used for the production of bioactive peptides in B. subtilis.

• Journal of the Korea Convergence Society
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• v.10 no.5
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• pp.27-34
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• 2019

In this paper, we propose a method to remove the background area by analyzing the pattern of the character area. In the character detection result of the MSER(Maximally Stable External Regions) method which distinguishes a region having a constant contrast background regions were detected. To solve this problem, we use the MSER method in natural images, the background is removed by calculating the change rate by searching the character area and the background area which are not different from the areas where the contrast values are different from each other. However, in the background removed image, using the LBP(Local Binary Patterns) method, the area with uniform values in the image was determined to be a character area and character detection was performed. Experiments were carried out with simple images with backgrounds, images with frontal characters, and images with slanted images. The proposed method has a high detection rate of 1.73% compared with the conventional MSER and MSER + LBP method.

• Ecology and Resilient Infrastructure
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• v.10 no.1
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• pp.20-30
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• 2023

This study analyzed the possibility of inland navigation in the Han river mouth, from Singok weir to the junction of Gongleung Stream. As a result of analysis using recent survey data and water level data, it was found that the number of days that a 250 - 400 ton class vessel can operate in the Han river estuary is less than 119 days per year. In the case of a 400 - 1,500 ton class vessel, it was found that only about 47 days per year can be operated. In this region, even in the absence of large-scale floods, the river bed continues to change significantly due to strong tides, indicating that there are limitations in securing a stable waterway. Therefore, for stable inland navigation, it is judged that continuous investigation and analysis of the possibility and stability of waterways are necessary.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.1
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• pp.26-33
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• 2022

Anterior tooth spacing is observed by pathological tooth movement (PTM), which is common in periodontal patients. And various occlusal factors contribute to PTM, especially in the maxillary anterior region, when there is excessive occlusal force, flaring due to position problem easily occurs. Teeth with loss of periodontal support tissue can secure stability when expanding the support area through intentional splinting, and change the occlusion when restored as a fixed prosthesis. After confirming the stable occlusion through the provisional prosthesis, it can be transferred to the final prosthesis through CAD-CAM. In this case, we present a long-term stable case through accurate diagnosis and treatment of the maxillary anterior teeth that have lost interdental contact.

• Journal of Animal Science and Technology
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• v.65 no.4
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• pp.792-803
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• 2023

This study aimed to assess the impact of weather events on the sorghum-sudangrass hybrid (Sorghum bicolor L.) cultivar production trend in the central inland region of Korea during the monsoon season, using time series analysis. The sorghum-sudangrass production data collected between 1988 and 2013 were compiled along with the production year's weather data. The growing degree days (GDD), accumulated rainfall, and sunshine duration were used to assess their impacts on forage production (kg/ha) trend. Conversely, GDD and accumulated rainfall had positive and negative effects on the trend of forage production, respectively. Meanwhile, weather events such as heavy rainfall and typhoon were also collected based on weather warnings as weather events in the Korean monsoon season. The impact of weather events did not affect forage production, even with the increasing frequency and intensity of heavy rainfall. Therefore, the trend of forage production for the sorghum-sudangrass hybrid was forecasted to slightly increase until 2045. The predicted forage production in 2045 will be 14,926 ± 6,657 kg/ha. It is likely that the damage by heavy rainfall and typhoons can be reduced through more frequent harvest against short-term single damage and a deeper extension of the root system against soil erosion and lodging. Therefore, in an environment that is rapidly changing due to climate change and extreme/abnormal weather, the cultivation of the sorghum-sudangrass hybrid would be advantageous in securing stable and robust forage production. Through this study, we propose the cultivation of sorghum-sudangrass hybrid as one of the alternative summer forage options to achieve stable forage production during the dynamically changing monsoon, in spite of rather lower nutrient value than that of maize (Zea mays L.).

• The KIPS Transactions:PartC
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• v.13C no.5 s.108
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• pp.627-634
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• 2006

Overlay network eliminates the need to change the application-layer tree when the underlying network changes and enables the overlay network to survive in environments where nonmember nodes do not support multicast functionality. An overlay protocol monitors group dynamics, while underlying unicast protocols track network dynamics, resulting in more stable protocol operation and low control overhead even in a highly dynamic environment. But, if overlay multicast protocols does not know the location information of node, this makes it very difficult to build an efficient multicasting tree. So, we propose a Hierarchical Overlay Multicast Architecture (HOMA) with the location information. Because proposed architecture makes static region-based dynamic group by multicast members, it is 2-tired overlay multicasts of application layer that higher layer forms overlay multicast network between members that represent group, and support multicast between multicast members belonging to region at lower layer. This use GPS, take advantage of geographical region, and realizes a region-sensitive higher layer overlay multicast tree which is impervious to the movements of nodes. The simulation results show that our approach solves the efficiency problem effectively.

• Korean Journal of Ichthyology
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• v.19 no.3
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• pp.225-235
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• 2007

The freshwater fish fauna and physical characteristics of streams in Yeosu peninsula and Geumo Islands were surveyed at thirty nine stations in the period of 2003 and 2005. Most of the streams were short in length and narrow in flowing water width. Main materials of riverbed in most stations were cobble, pebble and gravel; those in the stations adjacent river mouth gravel and sand. In the river type, eighteen stations out of surveyed stations were upstream type: Aa. Thirty nine fish species belonging sixteen families were caught in this survey region. Among them twenty seven species were primary freshwater fishes and nine were peripheral. In the species composition of each family, there were the most species in Cyprinidae and Gobiidae, twelve and ten species, respectively. Endemic species of Korean peninsula in this region were eight species. One exotic fish species, Lepomis macrochirus was found in Yeosu peninsula. Dominant species in each district was Zacco temminckii in Yeosu peninsula, Rhinogobius brunneus in Dolsan Island, Leucopsarion petersii in Geumo island and Oryzias latipes in Gae island. In the analysis of community structure, it was appeared that the community of Yeosu peninsula was the most diverse and stable in this region; as the size of island became smaller, diversity and richness of community decreased. Kichulchoia brevifasciata did not caught in this survey, and it is possible that the species was extincted in this island. Acanthorhodeus gracilis and L. petersii were reported firstly in this region.