• Convergence Security Journal
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• v.23 no.4
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• pp.93-100
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• 2023

This paper presents a novel approach for assigning group keys within a dynamic swarm unmanned system environment. In this environment, multiple groups of unmanned systems have the flexibility to merge into a single group or a single unmanned system group can be subdivided into multiple groups. The proposed protocol encompasses two key steps: group key generation and sharing. The responsibility of generating the group key rests solely with the leader node of the group. The group's leader node employs a secret sharing scheme to fragment the group key into multiple fragments, which are subsequently transmitted. Nodes that receive these fragments reconstruct a fresh group key by combining their self-generated secret fragment with the fragment obtained from the leader node. Subsequently, they validate the integrity of the derived group key by employing the hash function. The efficacy of the proposed technique is ascertained through an exhaustive assessment of its security and communication efficiency. This analysis affirms its potential for robust application in forthcoming swarm unmanned system operations scenarios characterized by frequent network group modifications.

• Journal of Korea Port Economic Association
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• v.27 no.1
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• pp.13-30
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• 2011

It's vital to establish the competitive comparative advantage as the competitions among global logistics companies have become fierce. The global companies, hence, must innovate their Port Hinterland to hub and spoke in a view of SCM. The Port Hinterland significantly affects its local economy and value added. The task of the Port Hinterland nowadays is to improve its efficiencies by utilizing logistics operations and services. The Korean government has planned to reduce the scale of the Port. The CCR and BCC matrices show that there are nine efficient companies: two companies in Gwangyang Hinterland and five companies in Busan Hinterland, though Masan FTZ was only ranked on the 24th, on the rank of world FTZ. This paper aims at finding the cargo volume necessary for achieving the maximum efficiency. This research proposes an appropriate strategy to keep a certain amount of cargo volume stable and presents the Port Hinterland differentiation strategies of Gwangyang and Busan.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.287-297
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• 2019

Responding to the rapid delivery demands and variety of small-volume products through human resource-dependent logistics operations in online markets is difficult. Logistics robots in fulfillment centers are expected to increase due to difficulties in hiring workers and rising labor costs. Amazon operates more than 100,000 robots in its Fulfillment centers. Alibaba, DHL, and UPS are also introducing robot technology to improve the logistics efficiency. Logistics robots are being used actively in the fierce online market competition of the global distribution industry. On the other hand, Korea is relatively sluggish. To revitalize the introduction of logistics robots in Korea, it is necessary to examine the factors that influence acceptance. The description of acceptability was based on an expanded technology acceptance model that has been verified through various studies. Studies have shown that both the ease and usefulness of purchasing have significant effects, and that ease has the greatest effect. The more experience involved, the more innovative, the more positive. The usefulness was shown to be positive as the perceived risks are low, price efficiency is good, and social impact is greater. This study provides theoretical and practical implications for logistics robot development and marketing.

• Journal of KIISE:Databases
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• v.30 no.5
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• pp.451-463
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• 2003

Recently, there have been various research efforts to develop strategies for accelerating OLAP operations on huge amounts of spatio-temporal data. Most of the work is based on multi-tree structures which consist of a single R-tree variant for spatial dimension and numerous B-trees for temporal dimension. The multi~tree based frameworks, however, are hardly applicable to spatio-temporal OLAP in practice, due mainly to high management cost and low query efficiency. To overcome the limitations of such multi-tree based frameworks, we propose a new approach called Hilbert Cube(H-Cube), which employs fractals in order to impose a total-order on cells. In addition, the H-Cube takes advantage of the traditional Prefix-sum approach to improve Query efficiency significantly. The H-Cube partitions an embedding space into a set of cells which are clustered on disk by Hilbert ordering, and then composes a cube by arranging the grid cells in a chronological order. The H-Cube refines cells adaptively to handle regional data skew, which may change its locations over time. The H-Cube is an adaptive, total-ordered and prefix-summed cube for spatio-temporal data warehouses. Our approach focuses on indexing dynamic point objects in static spatial dimensions. Through the extensive performance studies, we observed that The H-Cube consumed at most 20% of the space required by multi-tree based frameworks, and achieved higher query performance compared with multi-tree structures.

• The Journal of the Korea Contents Association
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• v.12 no.1
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• pp.369-378
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• 2012

Asthma requires continuous long-term management with at least 5% outcome of general population as well as being the second cause of death and disability after cancer. The present study developed an efficient self management system based on the commercial mobile phone network. The spirometric test results are input to the mobile phone through the communication line connected to the portable spirometer. The doctor or the care-giver can search, identify, and review the data accumulated daily by the patient, and feedback to the patient necessary recommendations by short message and color mail services. Patient can also send an emergency call to the doctor and/or the care-giver. User interface was designed as convenient as possible for maximum efficiency of these operations. The present system provides a desired remote medical services, thus would enhance health management of chronic diseased patients.

• Journal of Advanced Navigation Technology
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• v.28 no.4
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• pp.420-427
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• 2024

This study proposes a method for utilizing flight and flow - information for a collaborative environment (FF-ICE) for flight plan management based system wide information management (SWIM) technology for the safe and efficient operation of urban air mobility (UAM). SWIM provides a standardized infrastructure for air traffic data, enabling seamless information exchange among various stakeholders. This study purposed flight plan procedures for UAM operation regarding submitting preliminary and filed flight plans, validation and operational evaluation processes, state management, and the roles of each stakeholder. The system developed through the SWIM infrastructure for low-density urban air mobility traffic management. The study are expected to significantly enhance the safety and efficiency of UAM operations through strategic flight plan management methods.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.15-20
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• 2017

The International Maritime Organization(IMO) has adopted and implemented compulsory regulation for reducing greenhouse gas emission that cause global warming. However, with global warming underway, the IMO plans to enforce voluntary carbon dioxide emissions reduction based on the Ship Energy Efficient Management Plan and the Energy Efficiency Operational Indicator(EEOI) in the near future. Large container ships sail at low speeds in order to save fuel and reduce carbon dioxide emissions. However, bulbous bows designed for high-speed ships decrease fuel efficiency by acting as resistance when reduced speeds are adopted by large container ships. In order to adopt low-speed operations and increase fuel savings, the bulbous bow of a large container ship was modified into the proper shape and size. Fuel consumption was compared for checking the result of EEOI before and after modifying the bulbous bow adopted on low speed operation of large high-speed ships. The results confirmed much larger carbon dioxide emissions reduction than expected. If EEOI would be implemented as compulsory regulation for reducing carbon dioxide emissions, bulbous bow modification can be considered as one of the fuel saving methods for the high-speed ships.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.690-698
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• 2023

Information sharing and decision making between airport stakeholders became possible after the introduction of airport cooperative making system (A-CDM). This also resulted in optimizing aircraft handling time and increased the efficiency of aircraft operations. Technological advances have recently led to the development of urban air mobility (UAM) which is a small aircraft taking off and landing vertically. It is emerging as a new air transportation system in the future due to its advantage of saving time and solving congestion problem in the urban area. This study aims to suggest how vertiport cooperative decision making system (V-CDM) should be managed for efficient operation of UAM. By establishing procedure for decision making system based on Vertiport ecosystem of UAM. By establishing procedure for decision making system based on Vertiport ecosystem and UAM aircraft, unnecessary flight delays or cancellations can be minimized and efficiency of UAM operation will be improved as well.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.5
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• pp.252-259
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• 2007

With the rapid development of multimedia applications and wireless communication networks, consumer demand for video-over-wireless capability on mobile computing systems is growing rapidly. In this regard, this paper introduces YUV-aware instructions that enhance the performance and efficiency in the processing of color image and video. Traditional multimedia extensions (e.g., MMX, SSE, VIS, and AltiVec) depend solely on generic subword parallelism whereas the proposed YUV-aware instructions support parallel operations on two-packed 16-bit YUV (6-bit Y, 5-bits U, V) values in a 32-bit datapath architecture, providing greater concurrency and efficiency for color image and video processing. Moreover, the ability to reduce data format size reduces system cost. Experiment results on a representative dynamically scheduled embedded superscalar processor show that YUV-aware instructions achieve an average speedup of 3.9x over the baseline superscalar performance. This is in contrast to MMX (a representative Intel#s multimedia extension), which achieves a speedup of only 2.1x over the same baseline superscalar processor. In addition, YUV-aware instructions outperform MMX instructions in energy reduction (75.8% reduction with YUV-aware instructions, but only 54.8% reduction with MMX instructions over the baseline).

• The KIPS Transactions:PartB
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• v.10B no.4
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• pp.389-396
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• 2003

In this paper, we present a Korean partial parser based on rules, which is used for running applications such as a grammar checker and a machine translation. Basically partial parsers construct one or more morphemes and/or words into one syntactical unit, but not complete syntactic trees, and accomplish some additional operations for syntactical parsing. The system described in this paper adopts a set of about 140 manually-written rules for partial parsing. Each rule consists of conditional statements and action statement that defines which one is head node and also describes an additional action to do if necessary. To observe that this approach can improve the efficiency of overall processing, we make simple experiments. The experimental results have shown that the average number of edges generated in processing without the partial parser is about 2 times more than that with the partial parser.