• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.5C
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• pp.523-531
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• 2003

Java applets are downloaded from web server through internet and executed in Java Virtual Machine of clients'browser. Before execution of java applets, JVM checks bytecode program with bytecode verifier and performs runtime tests with interpreter. However, these tests will not protect against undesirable runtime behavior of java applets, such as denial of service attack, email forging attack, URL spoofing attack, or annoying sound attack. In order to protect malicious applets, a technique used in this paper is java bytecode modification. This technique is used to restrict applet behavior or insert code appropriate to profiling or other monitoring efforts. Java byte modification is divided into two general forms, class-level modification involving subclassing non-final classes and method-level modification used when control over objects from final classes or interface. This paper showed that malicious applets are controlled by java bytecode modification using proxy server. This implementation does not require any changes in the web sever, JVM or web browser.

• Journal of Digital Contents Society
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• v.13 no.2
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• pp.235-245
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• 2012

This paper introduce a quiz game contents based on gesture interface. We analyzed the off-line quiz games, extracted its presiding components, and digitalized them so that the proposed game contents is able to substitute for the off-line quiz games. We used the Kinect camera to obtain the depth images and performed the preprocessing including vertical human segmentation, head detection and tracking and hand detection, and gesture recognition for hand-up, hand vertical movement, fist shape, pass and fist-and-attraction. Especially, we defined the interface gestures designed as a metaphor for natural gestures in real world so that users are able to feel abstract concept of movement, selection and confirmation tangibly. Compared to our previous work, we added the card compensation process for completeness, improved the vertical hand movement and the fist shape recognition methods for the example selection and presented an organized test to measure the recognition performance. The implemented quiz application program was tested in real time and showed very satisfactory gesture recognition results.

• Spatial Information Research
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• v.7 no.2
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• pp.209-221
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• 1999

In this research, AVL-GIS(Automatic Vehicle Location System linked with Geographic Information System) system was developed using integration of core techniques of GIS engine written by Java language, GOS(Global Positioning System) and wireless telecommunication interfacing techniques. IDGPS(Inverted differential GPS) techniques was employed to estimate accurate position of mobile vehicle and to supervise their path from AVL-GLS control center system. Between mobile vehicle and AVL-GLS control center system which has spatial data analysis function, road network and rleate ddata base were connected wireless phone to communicate for position an dmessage in real time. The developed system from this research has more enhanced GIS functions rather than previous AVL oriented system which has MDT for message display and voice communication only. This system can support build-up application system such as fleet management like bus, taxi, truck, disaster and emergency and monitoring of transportation status for customer s order via web browser in filed of EC/CALS in low cost.

• Journal of the Korea Society for Simulation
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• v.21 no.3
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• pp.1-9
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• 2012

This paper proposes automatic precision approach radar (PAR) control system using digital signal to increase the safety of aircraft, and discrete event systems specification (DEVS) methodology is utilized to verify the proposed system. Traditionally, a landing aircraft is controlled by the human voice of a final approach controller. However, the voice information can be missed during transmission, and pilots may also act improperly because of incorrectness of auditory signals. The proposed system enables the stable operation of the aircraft, regardless of the pilot's capability. Communicating DEVS (C-DEVS) is used to analyze and verify the behavior of the proposed system. A composed C-DEVS atomic model has overall composed discrete state sets of models, and the state sequence acquired through full state search is utilized to verify the safeness and the liveness of a system behavior. The C-DEVS model of the proposed system shows the same behavior with the traditional PAR control system.

• Journal of the Korea Society of Computer and Information
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• v.12 no.4
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• pp.69-75
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• 2007

On the wireless communication between RFID Tag and Reader, there are some existing problems with weaknesses of security such as spoofing, replay, traffic analysis, position tracking, etc., in the established hash lock related algorithm. This paper has presented the comparison and analysis of the established hash lock related algorithm for privacy and in order to make up for this, also suggested a new security authentication algorithm based on hash which has an authentication protocol and creates hash function by using random numbers received from the reader on real time and every session. The algorithm suggested here can offer a several of usefulness for RFID authentication system and it has an advantage to reduce the amount of calculations compared to established algorithm. It also uses the tags needed among a lot of tags around which are expected later and it is expected to reduce a responsibility of the server by ending unnecessary tags' operation with time based.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.12
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• pp.99-107
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• 1998

A stereo vision system such as the structure of human's eyes has two cameras at separated positions from which we can obtain two input images and then put them together to create 3-D image. It can show more virtual effect than the conventional 2-D image system. But, the stereo image system has to control the convergence angle so that the stereo disparity could always be zero because observers can be fatigued and unconscious of stereo image in conditions that the stereo disparity is not zero for a long work. Therefore, in the paper, optical JTC system which can process adaptive tracking of a specific moving object is proposed as a new approach to keep the stereo disparity to be zero. In this method, optical JTC system obtains the values of the relative locations of a moving objects in left and right images and then these values are used for maintaining the stereo disparity to be zero. Through some optical experiments the proposed stereo vision system is proved to be insensitive to background noises and operate in real-time.

• Journal of Digital Convergence
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• v.13 no.5
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• pp.159-167
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• 2015

The nature of port logistics requires global visibility and traceability. However, the traditional RFID technology still applied cannot meet these demands. IP-USN and M2M in port logistics have faced challenges of the prerequisite of network composition and immense communications at the base where a grand number of containers are installed. To resolve the issue, this study suggests an IP-RFID-based smart port logistics service platform. The IP-RFID-based port logistics service system resolved the communication problem by separating the RFID tag and AP, which allows internet connection, from the tag. The tags connected with thermo-sensors, humidity sensors, pressure sensors, GPS, etc. are attached to the containers insuring global visibility and traceability, key factors in logistics, by obtaining desired real-time information regardless of time and location.

• Journal of Information Technology Services
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• v.10 no.1
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• pp.105-116
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• 2011

With recent spotlight on the, uniquitous computing technology, the need for object of indentification and location infrastructure has increased. Such GPS technolgy must utilize IEEE 802.15.4 Zigbee used for existing wireless sensor network infra as a basice element for user's context-awareness in a uniquitous environement, for effectiveness.Such real-time GPS service is provided in the internal environment where the user would actually are and most high-rise buildlings apply. Underthe assumption, the real-time GPS technology is seperated by each floor, and signals do not get transmitted to other floors, the application on one floor within the high-rise buildling was conducted. This study intends to suggest a floor detection algorithm using IEE 802.15.3/Zigbee's RSSI which supports the accuracy within a couple of meters for the user's the movement between the floors in high-rise buildings in a complex environment. It proposes an floor detection algorithm using IEEE 802.15.4/Zigbee's RSSI which provides accuracy within a radius of few meters for the users movement between the floors for real-time location tracking within high-rise building in a cmoplex environment. Furthermore, for more accurate real-time location tracking, it suggests an algorithm for real-time location tracking using IEEE 802.15.4a/Zigbee's CSS technology based on triangulation. Based on the suggested algorithm, it designs a hybrid real-time location tracking service system in a high-rise buildling and test its functions.

• Journal of Energy Engineering
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• v.24 no.1
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• pp.123-131
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• 2015

This paper aims to identify and clarify the cyber security risks and their interaction with the power system in Smart Grid. The EMS and other communication networks interact with the power system on a real time basis, so it is important to understand the interaction between two layers to protect the power system from potential cyber threats. In this study, the optimal power flow(OPF) and Power Flow Tracing are used to assess the interaction between the EMS and the power system. Through OPF and Power Flow Tracing based analysis, the physical and economic impacts from potential cyber threats are assessed, and thereby the quantitative risks are measured in a monetary unit.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.2
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• pp.319-325
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• 2014

Since smart phones or tablet PCs have been widely used recently, the users can create and edit documents anywhere in real time. If the input and edit flows of documents can be traced, it can be used as evidence in digital forensic investigation. The typical document application is the MS(Microsoft) Office. As the MS Office applications consist of two file formats that Compound Document File Format which had been used from version 97 to 2003 and OOXML(Office Open XML) File Format which has been used from version 2007 to now. The studies on MS Office files were for making a decision whether the file has been tampered or not through detection of concealed items or analysis of documents properties so far. This paper analyzed the input order of text cells on MS Excel files and shows how to figure out what cell is the last edited in digital forensic perspective.