• KIPS Transactions on Computer and Communication Systems
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• v.6 no.11
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• pp.463-468
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• 2017

To sense a wide area with mobile nodes, the uniformity of node deployment is a very important issue. In this paper, we consider the coverage problem to sense big data in sparse mobile ad hoc networks. In most existing works on the coverage problem, it has been assumed that the number of nodes is large enough to cover the area in the network. However, the coverage problem in sparse mobile ad hoc networks differs in the sense that a long-distance between nodes should be formed to avoid the overlapping coverage areas. We formulate the sensor coverage problem in sparse mobile ad hoc networks and provide the solution to the problem by a self-organized approach without a central authority. The experimental results show that our approach is more efficient than the existing ones, subject to both of coverage areas and energy consumption.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.556-560
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• 2013

Recently, solutions to accommodate explosively growing mobile data traffic have attracted intensive attentions since the emergence of high-performance smartphones. Spectrum which can be exploited for mobile communications is very limited. Thus, femto cell is considered as an alternative because it can efficiently offload mobile data traffic from macro cells without using additional spectrum. In this paper, we mathematically analyzed the coverage of femto cell when it is deployed in an area where there exists signals from existing macro base stations. Our numerical results indicate that the coverage of femto cell increases as the total power of femto cell increases or the ratio of power allocated to pilot channel increases. However, it is also shown that the coverage of femto cell is very limited despite its high power when interference signals from macro base stations are strong.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.2
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• pp.19-27
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• 2012

In railway tunnel environment, the reliability of a high-data-rate and real-time train-to-wayside communication should be maintained especially when high-speed train moves along the track. In China and Europe, the communication frequency around 900 MHz is widely used for railway applications. At this carrier frequency band, both of the solutions based on continuously laid leaky coaxial cable (LCX) and discretely installed base-station antennas (BSAs), are applied in tunnel radio coverage. Many available works have concentrated on the radio-wave propagation in tunnels by different kinds of prediction models. Most of them solve this problem as natural propagation in a relatively large hollow waveguide, by neglecting the transmitting/receiving (Tx/Rx) components. However, within such confined areas like railway tunnels especially loaded with train, the complex communication environment becomes an important factor that would affect the quality of the signal transmission. This paper will apply a full-wave numerical method to this case, for considering the BSA or LCX, train antennas and their interacted environments, such as the locomotive body, overhead line for power supply, locomotive pantograph, steel rails, ballastless track, tunnel walls, etc.. Involving finite-difference time-domain (FDTD) method and uni-axial anisotropic perfectly matched layer (UPML) technique, the entire wireless RF downlinks of BSA and LCX to tunnel space to train antenna are precisely modeled (so-called integrative modeling technique, IMT). When exciting the BSA and LCX separately, the field distributions of some cross-sections in a rectangular tunnel are presented. It can be found that the influence of the locomotive body and other tunnel environments is very significant. The field coverage on the locomotive roof plane where the train antennas mounted, seems more homogenous when the side-laying position of the BSA or LCX is much higher. Also, much smoother field coverage solution is achieved by choosing LCX for its characteristic of more homogenous electromagnetic wave radiation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.3
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• pp.901-920
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• 2015

Wireless Sensor Networks (WSNs) are widely used in geographically isolated applications like military border area monitoring, battle field surveillance, forest fire detection systems, etc. Uninterrupted power supply is not possible in isolated locations and hence sensor nodes live on their own battery power. Localization of sensor nodes in isolated locations is important to identify the location of event for further actions. Existing localization algorithms consume more energy at sensor nodes for computation and communication thereby reduce the lifetime of entire WSNs. Existing approaches also suffer with less localization coverage and localization accuracy. The objective of the proposed work is to increase the lifetime of WSNs while increasing the localization coverage and localization accuracy. A novel intelligent unmanned aerial vehicle anchor node (IUAN) is proposed to reduce the communication cost at sensor nodes during localization. Further, the localization computation cost is reduced at each sensor node by the proposed intelligent arc selection (IAS) algorithm. IUANs construct the location-distance messages (LDMs) for sensor nodes deployed in isolated locations and reach the Control Station (CS). Further, the CS aggregates the LDMs from different IUANs and computes the position of sensor nodes using IAS algorithm. The life time of WSN is analyzed in this paper to prove the efficiency of the proposed localization approach. The proposed localization approach considerably extends the lifetime of WSNs, localization coverage and localization accuracy in isolated environments.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.1
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• pp.30-36
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• 2009

Dedicated Short Range Communication (DSRC) systems in urban areas are used to collect traffic information from vehicles and to provide vehicles with information received from Roadside Equipment (RSE) having a range of 100 meters (m). However, it is not practical to use RSE with a range of 100 m for express highways. In this paper, we expand the standard cell coverage of RSE to 300 m, and adopt fixed relays to cover sites that cannot communicate with the RSE. We demonstrate that the system using the fixed relays is more economical than using only RSE.

• Journal of Preventive Medicine and Public Health
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• v.43 no.3
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• pp.279-282
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• 2010

Objectives: This study investigates whether Korean news media pay more attention to emerging diseases than chronic ones, and whether they closely follow the changes in the magnitude of health risks of chronic or well-known diseases. These two features are expected to appear as the result of surveillance function served by health journalism that should be the main source of the public's risk perception. Methods: The number of stories published in 10 newspapers containing the words, 'SARS,' 'Bovine Spongiform Encephalopathy,' 'Avian Influenza,' and 'Influenza A virus' was compared with the number of stories on chronic or wellknown diseases. We also counted the annual number of stories, published in a 12-year period, containing following terms: 'cancer,' 'diabetes,' 'hypertension,' 'pneumonia,' and 'tuberculosis.' The number was compared with the actual mortality of each disease. Results: Although cancer represented the primary cause of mortality, the newspapers covered key emerging diseases more than cancer or other well-known diseases. Also, media coverage of 'pneumonia' and 'tuberculosis' did not vary in accordance with changes in the mortality of each disease. However, the news media coverage did vary in accordance with the mortality of 'cancer,' 'diabetes,' and 'hypertension.' Conclusions: Korean health journalism was found to have both strong and weak points. The news media reduced the relative level of attention given to pneumonia and tuberculosis. Bearing in mind the major influence of news coverage on risk perception, health professionals need to be more proactive about helping to improve Korean health journalism.

• International journal of advanced smart convergence
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• v.12 no.4
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• pp.8-19
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• 2023

This paper presents advancement in multi- unmanned aerial vehicle (UAV) cooperative area surveillance, focusing on optimizing UAV route planning through the application of genetic algorithms. Addressing the complexities of comprehensive coverage, two real-time dynamic path planning methods are introduced, leveraging genetic algorithms to enhance surveillance efficiency while accounting for flight constraints. These methodologies adapt multi-UAV routes by encoding turning angles and employing coverage-driven fitness functions, facilitating real-time monitoring optimization. The paper introduces a novel path planning model for scenarios where UAVs navigate collaboratively without predetermined destinations during regional surveillance. Empirical evaluations confirm the effectiveness of the proposed methods, showcasing improved coverage and heightened efficiency in multi-UAV path planning. Furthermore, we introduce innovative optimization strategies, (Foresightedness and Multi-step) offering distinct trade-offs between solution quality and computational time. This research contributes innovative solutions to the intricate challenges of cooperative area surveillance, showcasing the transformative potential of genetic algorithms in multi-UAV technology. By enabling smarter route planning, these methods underscore the feasibility of more efficient, adaptable, and intelligent cooperative surveillance missions.

• Journal of Internet Computing and Services
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• v.25 no.3
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• pp.55-70
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• 2024

This study aims to compare the differences in the carbon neutral agendas of the two countries based on the differing interest positions of the media in the two countries, as well as to analyze the carbon neutral media coverage in South Korea and China. It also seeks to identify the major topics emphasized in the carbon neutral news agenda setting process in the two countries. A total of 49,227 news articles from South Korea and 105,680 news articles from China, covering the period from the declaration of carbon neutrality in both countries in 2020 to May 9, 2022, were collected. CONCOR and topic modeling analyses were performed on these texts. The results found that South Korean media showed a preference for covering carbon neutrality from the perspective of its inhabitants, whereas Chinese media demonstrated a preference for covering carbon neutrality from the viewpoint of the nation. The discourses on coverages largely focus on areas such as energy strategy, business strategy, industrial growth, and international cooperation, with an obvious lack of discourse on the environment. The findings of this study expect to serve as a primary reference in establishing a news coverage strategy which is environmentally sustainable for the media.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.448-448
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• 2004

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1568-1569
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• 2005

This paper presents a method to optimize train radio communication network for train control(CBTC) or multimedia services. To determine the optimized distance between wayside radio stations in a radio communication network constructed along railway, radio frequency allocation and hand-over capability is studied in terms of radio communication cell coverage and roaming feasibility.