• 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 KIISE:Software and Applications
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• v.33 no.4
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• pp.378-387
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• 2006

A programming model for ubiquitous sensor network (USN) applications based on Nano-Qplus is proposed. USN applications mean programs of nodes which are components of sensor network such as sensor, router, sink and actuator. Developers can automatically generate programs of USN applications by setting attributes values of nodes using a script after they model a sensor network. A script for setting attributes values of a node is proposed in this paper. The algorithm of automatic code generation is also described. Developers can easily implement USN applications even if they do not know details of low-level communication, data sharing, and collective operations because the applications are automatically generated from a script. They set only attributes values of nodes using the script. Efforts for USN applications development also are reduced because of automatic code generation. Furthermore, developers can correct errors of applications in the early stage of development through ear]y test based on rapid code generation.

• Journal of Korea Multimedia Society
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• v.13 no.6
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• pp.901-910
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• 2010

$IP^2$, as an extended concept of the next generation IMT network, is a concept of basically supporting mobility using two steps of IP address (i.e. IPha (IP Host address) and IPra (IP routing address)) in IP backbone network. Current $IP^2$system has a shortcoming of excess usage of network resources caused by sending paging messages to all cells in LA (Location Area) in paging procedure. Considering the evolving direction of network, which is taking mobility with various speed and integration of devices into consideration, this shortcoming must be overcome. In this paper, we proposed a method to reduce time and memory for paging by maintaining current information of MN (Mobile Node) not in Active state with proxy server. Performance evaluation based on NS-2 simulations has shown that the efficiency of network resources is improved in the proposed method.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.10
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• pp.603-609
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• 2004

Procedural texture has many advantages that its representation is extremely compact and unfixed in resolution. However, it can be difficult for an end-user having no programming skill to build and debug. This paper presents a new interactive design system for procedural texture generation. The user's interactive design process based on multi-layer operations is represented with a graph structure, which consists of the data node, the operation and the output. Since our system generates automatically a shading language, a user who is not acquainted with implicit concepts can make procedural texturing by using an intuitive and flexible interface. Simulation results showed that the proposed method can make a variety of texture patterns efficiently.

• Journal of Astronomy and Space Sciences
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• v.37 no.3
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• pp.199-208
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• 2020

This paper presents a kinematic ephemeris generator for Korea Pathfinder Lunar Orbiter (KPLO) and its performance test results. The kinematic ephemeris generator consists of a ground ephemeris compressor and an onboard ephemeris calculator. The ground ephemeris compressor has to compress desired orbit propagation data by using an interpolation method in a ground system. The onboard ephemeris calculator can generate spacecraft ephemeris and the Sun/Moon ephemeris in onboard computer of the KPLO. Among many interpolation methods, polynomial interpolation with uniform node, Chebyshev interpolation, Hermite interpolation are tested for their performances. As a result of the test, it is shown that all the methods have some cases that meet requirements but there are some performance differences. It is also confirmed that, the Chebyshev interpolation shows better performance than other methods for spacecraft ephemeris generation, and the polynomial interpolation with uniform nodes yields good performance for the Sun/Moon ephemeris generation. Based on these results, a Kinematic ephemeris generator is developed for the KPLO mission. Then, the developed ephemeris generator can find an approximating function using interpolation method considering the size and accuracy of the data to be transmitted.

• Environmental Engineering Research
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• v.25 no.2
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• pp.238-242
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• 2020

Sediment microbial fuel cells (SMFCs) illustrated great potential for powering environmental sensors and bioremediation of sediments. In the present study, array anodes for SMFCs were fabricated with graphite rods as anode material and stainless steel plate as electric current collector to make it inconvenient to in situ settle down and not feasible for large-scale application. The results demonstrated that maximum power of 89.4 ㎼ was obtained from three graphite rods, twice of 43.3 ㎼ for two graphite rods. Electrochemical impedance spectroscopy revealed that three graphite rods resulted in anodic resistance of 61.2 Ω, relative to 76.0 Ω of two graphite rods. It was probably caused by the parallel connection of the graphite rods, as well as more biomass which could reduce the charge transfer resistance of the biofilm anode. The presently designed array configuration possesses the advantages of easy to enlarge the surface area, decrease in anodic resistance because of the parallel connection of each graphite rod, and convenience to berry into sediment by gravity. Therefore, the as prepared array node would be an effective method to fabricate large-scale SMFC and make it easy to in situ applicate in natural sediments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.49-53
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• 2007

The Next generation IP-based wireless access network proposed Mobile IP(IPv4) protocols to support mobility of node. Because Mobile IPv4 operates on th basis deigned IP in fixed network, it causes performance drop like triangle routing and handover delay. Therefore Mobile IPv4 needs scheme to complement this problems and to support service guaranteed QoS. Concerns about using MPLS networks in the next generation IP-based wireless access network are increasing. In our previous research, we proposed MCS&MUMCA, IP mobility management scheme. In this paper, we linkage the MCS&MUMCA in MPLS network and analyze its the performance.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.9
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• pp.351-358
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• 2006

In this paper, DSPOCS(Digital Switchgear-Panel Operation and Control Solution) is designed, which is the intelligent inference based operation and control solution to obtain the safety and reliability of electric power supply in substation based on IED. DSPOCS is designed as a scheduled monitoring and control task and a real-time alarm inference task, and is interlinked with BRES(Bus Reconfiguration Expert System) in the required case. The intelligent alarm inference task consists of the alarm knowledge generation part and the real-time pattern matching part. The alarm knowledge generation part generates automatically alarm knowledge from DB saves it in alarm knowledge base. On the other hand, the pattern matching part inferences the real-time event by comparing the real-time event information furnished from IEDs of substation with the patterns of the saved alarm knowledge base.; Especially, alarm knowledge base includes the knowledge patterns related with fault alarm, the overload alarm and the diagnosis alarm. In order to design the database independently in substation structure, busbar is represented as a connectivity node which makes the more generalized graph theory possible. Finally, DSPOCS is implemented in MS Visual $C^{++}$, MFC, the effectiveness and accuracy of the design is verified by simulation study to the typical distribution substation.

• Journal of KIISE:Software and Applications
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• v.33 no.9
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• pp.810-821
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• 2006

As XML is widely used across the computer related fields, and it costs expensive for its compiler, the study on the automatic generation of the compiler is becoming important. In addition, though the XMLSchema became a standard, there have been few works on the automatic compiler generation for XML applications based on the XMLSchema. In this paper, we introduce a method that we can automatically generate a compiler for an XML application based on the XMLSchema. Our XML compiler generator uses data type information in XMLSchema document and semantic information in another file and produces semantic classes and a compiler for the XML application. The compiler parses an XML document, builds a tree in which each node is an instance of semantic class, and processes the document through the traversal of the tree.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1996.04a
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• pp.70-77
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• 1996

Recently many efforts have been made to improve the efficiency of design and production of the structures using the automation system. But, this work has been progressed as independent or partial system. And, the study on the integrated system is not sufficient in application for practical problems yet. This paper deals with the fundamental concept of modeling system and application method on structural modeling. At first, the core of the integrated system is a shape modeling system that can represent the geometric and topological information. This system must be designed as an open system to be combined with each independent automation system. The appropriate concept to realize this system on structural modeling is object oriented modeling and this enables to integrate each automation system successfully, This concept was applied to automatic mesh generation. For shape modeling system, half-edge data structure that is being used in solid modeling was modified to handle the plate structure in the plane. And, to generate the triangular meshes, direct node connection method was used. And, as a result, the integrated system that generate the meshes of two dimensional structure automatically was realized. And, programmed by C++, these systems can be combined with other systems easily and have good reusability.