• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.1
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• pp.54-59
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• 2010

This paper present to study the guidance system as localization technique using sensor fusion and line tracking technique using virtual line for AGV(autonomous guided vehicle). An existing AGV could drive on decided line only. And representative guidance systems of such guidance system are magnet-gyro guidance and wired guidance. However, those have had the high cost of installation and maintenance, and the difficulty of system change according to variation of working environment. To solve such problems, we make the localization system which is fused with a laser navigation and gyro, encoder. The system is robust against noise, and flexible according to working environment through sensor fusion. For line tracking of laser navigation without wire guidance, we set the virtual line in program, and design the driving controller based on difference of angle and distance between AGV's position and decided virtual line. To experiment, we use the AGV which is made by ourselves, and experiment the line tracking repeatedly on same experimental environment. In result, maximum distance error between decided virtual line and AGV's position was less than 49.93mm, and we verified that the proposed system is efficient for line tracking of actual AGV.

• Journal of Korea Multimedia Society
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• v.14 no.1
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• pp.33-43
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• 2011

Routing technologies considering QoS-based hypermedia services have been seen as a crucial network property in next generation optical Internet (NGOI) networks based on IP/dense-wavelength division multiplexing (DWDM). The huge potential capacity of one single fiber. which is in Tb/s range, can be exploited by applying DWDM technology which transfers multiple data streams (classified and aggregated IP traffics) on multiple wavelengths (classified with QoS-based) simultaneously. So, DWDM-based optical networks have been a favorable approach for the next generation optical backbone networks. Finding a qualified path meeting the multiple constraints is a multi-constraint optimization problem, which has been proven to be NP-complete and cannot be solved by a simple algorithm. The majority of previous works in DWDM networks has viewed heuristic QoS routing algorithms (as an extension of the current Internet routing paradigm) which are very complex and cause the operational and implementation overheads. This aspect will be more pronounced when the network is unstable or when the size of network is large. In this paper, we propose a flooding-based unicast and multicast QoS routing methodologies(YS-QUR and YS-QMR) which incur much lower message overhead yet yields a good connection establishment success rate. The simulation results demonstrate that the YS-QUR and YS-QMR algorithms are superior to the previous routing algorithms.

• The Journal of the Korea Contents Association
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• v.13 no.3
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• pp.307-317
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• 2013

This study aims to investigate the research equipment establishing relationship by looking at research equipment information transfer that follows the network's structural and positional characteristics and the research institute's responsibilities to increase the possibility of research equipment usage by using the SNA(Social Network Analysis) method. Consequently, with the given structural characteristics of research institute, it can be concluded that because of its low density, it appears to be difficult to transfer research equipment information within the network. Government-funded research institutes that can effectively deliver research equipment information within the network system through comparison positional characteristics are ETRI, KITECH, KRICT, Sungkyungwan University, and Kyungbook National University. In addition, a virtualization node not only invigorates the network system but also acts as an intermediary factor to effectively deliver research equipment information. As results, there can be three conceivable alternatives to increase the possibility of research equipment usage. Those includes: 1. policy to encourage relationship building among research institutes 2. utilizing suitable institutes for effective delivery of research equipment information and lastly, 3. establishing a virtual intermediary institute for information sharing and utilization of isolated institutes' research equipments.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.11
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• pp.385-392
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• 2016

Recently, Expectation Area-based Real-time Routing (EAR2) protocol has been proposed to support real-time routing in wireless sensor networks. EAR2 considers the expectation area of a mobile sink and uses flooding within the expectation area. However, flooding leads to excessive energy consumption and causes long delay against real-time routing. Moreover, since EAR2 uses single path to the expectation area, it is difficult to support reliable routing in sensor networks with high link failures. Thus, to overcome these limitation of EAR2, this paper proposes a reliable and real-time routing protocol based on virtual grids and multipath for mobile sinks. To support real-time routing, the proposed protocol considers expectation grids belonged to the expectation area. Instead of flooding within the expectation area, the proposed protocol uses multicasting to the expectation grids and single hop forwarding in an expectation grid because the multicasting can save much energy and the single hop forwarding can provide short delay. Also, the proposed protocol uses multipath to the expectation grids to deal with link failures for supporting reliable routing. Simulation results show that the proposed protocol is superior to the existing protocols.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.5
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• pp.271-280
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• 2014

In wireless sensor networks, there have been two methods for sensing continuously moving object tracking: user-query based method and periodic report based method. Although the former method requires overhead for user query rather than the latter method, the former one is known as an energy-efficient method without transferring unnecessary information. In the former method, a virtual tree, consisting of sensor nodes, is exploited for the user querying and sensor reporting. The tree stores the information about mobile objects; the stored information is triggered to report by the user query. However, in case of fast moving object, the tracking accuracy reduces due to the time delay of end-to-end repeated query. To solve the problem, we propose a query relaying method reducing the time delay for mobile object tracking. In the proposed method, the nodes in the tree relay the query to the adjacent node according to the movement of mobile object tracking. Relaying the query message reduces the end-to-end querying time delay. Simulation results show that our method is superior to the existing ones in terms of tracking accuracy.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.4
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• pp.775-783
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• 2017

As interest in cloud computing grows, the number of users using cloud computing services is increasing. However, cloud computing technology has been steadily challenged by security concerns. Therefore, various security breaches are springing up to enhance the system security for cloud services users. In particular, research on detection of malicious VM (Virtual Machine) is actively underway through the introspecting virtual machines on the cloud platform. However, memory analysis technology is not used as a monitoring tool in the environments where multiple virtual machines are run on a single server platform due to obstructive monitoring overhead. As a remedy to the challenging issue, we proposes a computationally efficient instance memory introspection scheme to minimize the overhead that occurs in memory dump and monitor it through a partial memory monitoring based on the well-defined kernel memory map library.

• Journal of Korea Game Society
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• v.17 no.5
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• pp.123-132
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• 2017

The path-finding algorithm refers to an algorithm for navigating the route order from the current position to the destination in a virtual world in a game. The conventional path-finding algorithm performs graph search based on cost such as A-Star and Dijkstra. A-Star and Dijkstra require movable node and edge data in the world map, so it is difficult to apply online games with lots of map data. In this paper, we provide a Heuristic-based Genetic Algorithm Path-finding(HGAP) using Genetic Algorithm(GA). Genetic Algorithm is a path-finding algorithm applicable to game with variable environment and lots of map data. It seek solutions through mating, crossing, mutation and evolutionary operations without the map data. The proposed algorithm is based on Binary-Coded Genetic Algorithm and searches for a path by performing a heuristic operation that estimates a path to a destination to arrive at a destination more quickly.

• Journal of Korean Society of Transportation
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• v.24 no.3 s.89
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• pp.177-187
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• 2006

It is known that over one million car navigation devices are being currently used in Korea. Most. if not all, route guidance systems, however, Provide only one "best" route to users, not providing any options for various types of users to select. The current practice dose not consider each individual's different preferences. These days, a vast amount of information became available due to the rapid development in information processing technology. Thus, users Prefer choices to be given and like to select the one that suits him/her the "best" among available information. To provide such options in this Paper, we developed an algorithm that provides alternative routes that may not the "least cost" ones, but ones that are close to the "least cost" routes for users to select. The algorithm developed and introduced in the paper utilizes a link-based search method, rather than the traditional node-based search method. The link-based algorithm can still utilize the existing transportation network without any modifications, and yet enables to provide flexible route guidance to meet the various needs of users by allowing transfer to other modes and/or restricting left turns. The algorithm developed has been applied to a toy network and demonstrated successful implementation of the multi-path search algorithm for multi-purpose activities.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.2
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• pp.377-386
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• 2016

As the number of malware has been increased, it is necessary to analyze malware rapidly against cyber attack. Additionally, Dynamic malware analysis has been widely studied to overcome the limitation of static analysis such as packing and obfuscation, but still has a problem of exploring multiple execution path. Previous works for exploring multiple execution path have several problems that it requires much time to analyze and resource for preparing analysis environment. In this paper, we proposed efficient exploring approach for multiple execution path in a single analysis environment by pipelining processes and showed the improvement of speed by 29% in 2-core and 70% in 4-core through experiment.

• Journal of KIISE:Databases
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• v.27 no.2
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• pp.227-237
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• 2000

A Web database System is a large-scaled multimedia application system that has multimedia processing facilities and cooperates with relational/Object-Oriented DBMS. Conventional hypertext modeling methods and DB gateway have limitations for Web database because of their restricted versatile presentation abilities and inefficient concurrency control caused by bottleneck in cooperation processing. Thus, we suggest a Dynamic Navigation Model & Virtual Graph Structure. The Dynamic Navigation Model supports implicit query processing and dynamic creation of navigation spaces, and introduce node-link creation rule considering navigation styles. We propose a mapping methodology between the suggested hypertext model and the relational data model, and suggest a dynamic allocation scheduling technique for query processing server based on weighted value. We show that the proposed technique enhances the retrieval performance of Web database systems in processing complex queries concurrently.