• Journal of Positioning, Navigation, and Timing
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• v.10 no.4
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• pp.235-242
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• 2021

Unmanned Aerial Vehicles (UAVs), which were used for military purposes, are gradually expanding their application fields under the influence of electrification and digitalization. Starting from the field of aerial imaging and Intelligence Surveillance and Reconnaissance (ISR) mission, nowadays the possibility of Urban Air Mobility (UAM), which transports passengers and cargo with drones, is widely under discussion. In order to occupy the rapidly growing global unmanned aerial vehicle market in advance, it is necessary to secure core technologies and develop key UAVs components based on the new technologies. In the navigation field, it is necessary to secure a precise position with guaranteed reliability and continuity, unrelated to the operating environments. The reliability and continuity should be secured in the algorithm level and in the H/W component levels also. In order to achieve this technical goal, the Ministry of Science and ICT has launched the 'Unmanned Vehicle Core Technology Research and Development Program' in 2019 to support the R&D on the unmanned vehicle technologies. In this paper, authors introduce the unmanned vehicle core technology research and development program to the related researchers. The authors summarize the backgrounds of the program and show the technological tasks and objectives on the sub-programs in the unmanned vehicle navigation program. We present the program schedules especially focused on the test and evaluation of the developed technologies and components.

• Journal of Hydrogen and New Energy
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• v.33 no.6
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• pp.769-775
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• 2022

Global efforts to reduce carbon emissions have focused attention on the development of hydrogen energy and the development of various hydrogen mobility requires mobile hydrogen charging stations. In this study, the flow characteristics of the flow control hydrogen valve for mobile hydrogen charging equipment were studied according to the temperature change of hydrogen gas. The inlet pressure was 100 MPa, the outlet pressure to 70 MPa, and temperature condition was set -40℃ to 85℃. As a result, the difference in the valve flow coefficient, which determines the capacity of the valve, showed a difference within 5% depending on the temperature.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.590-593
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• 2011

Time goes on, Ad Hoc network is hot issues. So far, there are a lot of protocols have been proposed for Ad Hoc routing protocol to support the mobility. This paper presents an enhanced DSDV(Destination-Sequenced Distance Vector) routing protocol which nominates one node to take care of a specific area. Simply Area-Aware(AA) DSDV routing protocol has one nominee to take care of some area. It has two jobs. One is to take care of its neighbour and another is to transfer the routing table to its other node as it works. It is called as Area Nominee(AN). The new scheme extends the routing table to include the nominee in the area. The general node is the same as the previous DSDV routing protocol. In the other hands, the node which is nominated has two routing protocols. One is for Regional Routing(RR) table which is the same routing table in DSDV. Another is Global Routing(GR) table which is about the area round its area which it cares nearby. GR table is the table for the designated node like the nominee. Each area has one nominee to transfer between ANs. It has only nominee's information about every area. This concept decreases the topology size and makes the information of topology more accurate.

• Journal of Smart Tourism
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• v.3 no.4
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• pp.23-31
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• 2023

This paper explores the concept of enhanced smart tourism as a response to the challenges and opportunities arising in the post-pandemic tourism landscape. The COVID-19 pandemic has not only halted the global tourism industry but also prompted a reevaluation of its sustainability, technological integration, and impact on local communities. The need for a paradigm shift in tourism is emphasized, focusing on digitalization, innovation, and resilience. Enhanced smart tourism is characterized by a shift from traditional practices to innovative governance models, increased emphasis on sustainability, and the integration of technology for better management and visitor experiences. The paper discusses the four pillars of enhanced smart tourism - Technology, Sustainability, Accessibility/Mobility, and Innovation/Creativity, and their expansion in the post-pandemic era. Furthermore, the significant role of data in smart tourism is examined, highlighting the importance of data valuation, management, and ethics. The paper proposes frameworks and methods for data valuation and emphasizes the necessity of a comprehensive approach to data within the smart tourism ecosystem. The conclusion points to the need for further empirical and conceptual research to fully realize the potential of enhanced smart tourism.

• Journal of Positioning, Navigation, and Timing
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• v.13 no.1
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• pp.15-23
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• 2024

One of the core keywords in the fourth industrial revolution is convergence, and the convergence of the production, distribution, and consumption processes of services is particularly important. The convergence of user services is underway in various industrial fields including mobile communications, healthcare, mobility, artificial intelligence, etc. In order to offer these converged services efficiently, it is necessary to provide accurate user-centric location information, which can be obtained by employing the global navigation satellite system (GNSS). In addition, as we have entered the post-COVID era, the demand for various fields such as a healthcare, customized tourism services, and aviation services based on accurate location information is exploding. In this paper, we present the results of a case study on the current research trends of GNSS used in telemedicine services and AI & IoT fields, and also analyze these results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.942-955
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• 2000

This paper proposes enhanced designs of global service logic and information flow for the mass-call based IN service, which increase call completion rates and optimize the resource in joint wired and wireless networks. In order to hanve this logic implemented, we design a Dynamic Queue Manager(DQM) applied to the call queuing service feature in the Service Control Point(SCP). In order to apply this logic to wireless service subscribers as well as wired service subscribers, the service registration flags between the Home Location Register(HLR) and the SCP are managed to notify the DQM of the corresponding service subscribers’ mobility. Hence, we present a dynamic queue management mechanism, which dynamically manages the service group and the queue size based on M/M/c/K queueing model as the wireless subscribers roam the service groups due to their mobility characteristics. In order to determine the queue size allocated by the DQM, we simulator and analyze the relationship between the number of the subscriber’s terminals and the drop rate by considering the service increment rate. The appropriate waiting time in the queue as required is simulated according to the above relationship. Moreover, we design and implement the DQM that includes internal service logic interacting with SIBs(Service Independent building Blocks) and its data structure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.5B
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• pp.253-263
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• 2005

This paper proposed a mobile multicast technique to satisfy end-to-end QoS for various user requirements in mobile network environment. In order to provide seamless mobility, fast handoff technique was applied. By using L2 mobile trigger, it was possible to minimize remarkable amount of packet loss by delay occurred during handoff. To provide efficient multicast, concept of hierarchy was introduced to Xcast++, which results in a creation of HXcast++. HXcast++ optimized transfer path of multicast and reduced expensive multicast maintenance costs caused by frequent handoff. Suggestion of GMA (Group Management Agent) mechanism allows joining to group immediately without waiting IGMP Membership query during handoff. GMA mechanism will minimize the delay for group registration process and the resource usage due to delay of withdrawal process. And also use of buffering & forwarding technique minimized packet loss during generation of multicast tree. IntServ/RSVP was used to provide End-to-End QoS in local domain and DiffServ was used in global domain. To minimize reestablishment of RSVP session delay, extended HXcast++ control messages ware designed to require PATH message. HXcast++ proposed in this thesis is defined as multicast technique to provide end-to-end QoS and also to satisfy various user requirements in mobile network environment.

• The KIPS Transactions:PartC
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• v.19C no.2
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• pp.99-118
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• 2012

In PMIPv6-based network, mobile nodes can be made smaller and lighter because the network nodes perform the mobility management-related functions on behalf of the mobile nodes. The one of the protocols, Fast Handovers for Proxy Mobile IPv6(FPMIPv6)[1] has studied by the Internet Engineering Task Force(IETF). Since FPMIPv6 adopts the entities and the concepts of Fast Handovers for Mobile IPv6(FMIPv6) in Proxy Mobile IPv6(PMIPv6), it reduces the packet loss. Conventional scheme has proposed that it cooperated with an Authentication, Authorization and Accounting(AAA) infrastructure for authentication of a mobile node in PMIPv6, Despite the best efficiency, without begin secured of signaling messages, PMIPv6 is vulnerable to various security threats such as the DoS or redirect attAcks and it can not support global mobility between PMIPv. In this paper, we analyze Kang-Park & ESS-FH scheme, and then propose an Enhanced Security scheme for FPMIPv6(ESS-FP). Based on the CGA method and the pubilc key Cryptography, ESS-FP provides the strong key exchange and the key independence in addition to improving the weaknesses for FPMIPv6. The proposed scheme is formally verified based on Ban-logic, and its handover latency is analyzed and compared with that of Kang-Park scheme[3] & ESS-FH and this paper propose inter-domain fast handover sheme for PMIPv6 using proxy-based FMIPv6(FPMIPv6).

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.2
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• pp.50-62
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• 2016

With programmable applications that utilize sensors, such as global positioning systems and accelerometers, smartphones provide an unprecedented opportunity to collect behavioral data in an unobtrusive and cost-effective manner. This paper assesses the relative accuracy and reliability of the Future Mobility Sensing (FMS), a smartphone-based prompted-recall travel survey. We compared the data extracted from FMS with the data collected from the Korea Passenger Trip Survey (PTS), a traditional self-reported, paper-based travel survey. In total, 46 undergraduate students completed the PTS for seven consecutive days, while also carrying their smartphones with the activated FMS applications for the same time span. After completing the PTS, the participants validated their FMS data on the web-based prompted recall surveys. We then matched the validated FMS data with the PTS-based records. The FMS turns out to be superior in detecting short trips, which are usually under-reported in self-reported travel surveys. The reported PTS travel times are longer than for the FMS, suggesting that participants tend to overestimate their travel time in the PTS. This study contributes to the ongoing development of smartphone-based travel behavior data collecting methods.

• International Journal of Computer Science & Network Security
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• v.21 no.3
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• pp.257-265
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• 2021

Modern methods of regulating migration processes in EU states include a wide variety of adapted, transformed under the sway of globalization tools in order to influence the movement of human capital within the European space. The main purpose of the regulatory policy on migration flows is the redistribution of professionally competent professionals between different spheres of life. Herewith, the determining factor in the effectiveness of such distribution is a rational combination of stimulating and disincentive levers of influence on the movement of citizens of different EU countries and taking into account the motives of such mobility. Modernization of migration management approaches can be a major economic, social, political and cultural progress of European countries. The purpose of the research is to conduct a detailed analysis of existing practices of migration flow management, in particular their stimulation or containment, and to outline key migration trends formed under the influence of multicomponent approaches to migration regulation, transformation of regulatory legislation and changing priorities of modern society. The research methods: statistical-analytical method; ARIS method; method of tabular, graphical and analytical modeling; comparative analysis; systematization, generalization. Results. Current pan-European methods of regulating migration processes are insufficiently adapted to the multinational socialeconomic space; consequently, there are some disparities in the distribution of migrants between EU countries, although the overall dynamics of migration is positive. Fluctuations in the population of European countries during 2000-2019 and trends in the transformation of social-economic space confirm the insufficient level of influence of current methods of regulating migration flows. Along with this, the presence of a characteristic asymmetry in the distribution of migrants requires a greater focus on the modernization of regulatory instruments, in particular, the regulatory mechanism for managing migration processes. As a result of the conducted study, further prospects for the implementation of alternative methods of regulating migration processes in EU states have been outlined; the current and projected limits for increasing the level of observance of migrants' rights at the European level have been clarified through the adoption of appropriate regulatory acts; effective solutions for intensifying the influx of high-quality labor resources from different countries to EU have been identified. The research results can be used to study methods of regulating migration processes in the countries in the global dimension.