• Journal of KIISE:Databases
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• v.33 no.3
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• pp.271-281
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• 2006

Recently the need for Location-Based Service (LBS) has increased due to the development and widespread use of the mobile devices (e.g., PDAs, cellular phones, labtop computers, GPS, and RFID etc). The core technology of LBS is a moving-objects database that stores and manages the positions of moving objects. To search for information quickly, the database needs to contain an index that supports both real-time position tracking and management of large numbers of updates. As a result, the index requires a structure operating in the main memory for real-time processing and requires a technique to migrate part of the index from the main memory to disk storage (or from disk storage to the main memory) to manage large volumes of data. To satisfy these requirements, this paper suggests a unified index scheme unifying the main memory and the disk as well as migration policies for migrating part of the index from the memory to the disk during a restriction in memory space. Migration policy determines a group of nodes, called the migration subtree, and migrates the group as a unit to reduce disk I/O. This method takes advantage of bulk operations and dynamic clustering. The unified index is created by applying various migration policies. This paper measures and compares the performance of the migration policies using experimental evaluation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.4
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• pp.371-377
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• 2013

Fishing boats more than 5 tons is obliged to VHF DSC by Fishing Vessels Act and Vessel Safety Act. The owner of the fishing vessel is equipped to the automatic position reporting device in accordance with the Notice of the Minister of Land, Transport and Maritime Affairs to regulations, shall be ensure to navigations safety and in order to respond quickly in the event of maritime accidents on fishing vessels. East sea set up to start in 2012, which is now underway the annual install plain to the yellow sea and the south sea for VHF coast stations. It is web-based remote operation of DSC on the remote control and monitoring in Fishery Information Communication Station for the coastal VMS construction project. All fishing vessels is VHF DSC in conjunction with the GPS that location information transmitted to the coast station. automatically by the DSC call. This paper has been studied on the communications coverage set up and traffic operation for realization a roaming service by navigation route tracking and RSSI techniques in parallel algorithm refer to VHF DSC coast stations in east sea.

• Journal of Digital Convergence
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• v.12 no.3
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• pp.243-248
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• 2014

Recently, solar energy is expanding to combination of computing in real time by tracking the position of the sun to estimate the angle of inclination and make up freshly correcting a part of the solar radiation. Solar power is need that reliably linked technology to power generation system renewable energy in order to efficient power production that is difficult to output predict based on the position of the sun rise. In this paper, we analysis of prediction model for solar power generation to estimate the predictive value of solar power generation in the development of real-time weather data. Photovoltaic power generation input the correction factor such as temperature, module characteristics by the solar generator module and the location of the local angle of inclination to analyze the predictive power generation algorithm for the prediction calculation to predict the final generation. In addition, the proposed model in real-time national weather service forecast for medium-term and real-time observations used as input data to perform the short-term prediction models.

• Journal of Industrial Convergence
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• v.18 no.5
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• pp.23-29
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• 2020

The Internet of things (IoT) is the extension of Internet connectivity into various devices and everyday objects. Embedded with electronics, Internet connectivity and other forms of hardware. The IoT poses significant risk to the entire digital ecosystem. This is because so many of these devices are designed without a built-in security system to keep them from being hijacked by hackers. This paper proposed a mutual authentication protocol for IoT Devices using symmetric-key algorithm. The proposed protocol use symmetric key cryptographic algorithm to securely encrypt data on radio channel. In addition, the secret key used for encryption is random number of devices that improves security by using variable secret keys. The proposed protocol blocked attacker and enabled legal deives to communicate because only authenticated devices transmit data by a mutual authentication protocol. Finally, our scheme is safe for attacks such as eavesdropping attack, location tracking, replay attack, spoofing attack and denial of service attack and we confirmed the safety by attack scenario.

• Journal of KIISE
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• v.43 no.7
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• pp.763-772
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• 2016

With the spread of smartphones containing multiple on-board sensors, the market for context aware applications have grown. However, due to the limited power capacity of a smartphone, users feel discontented QoS. Additionally, context aware applications require the utilization of many forms of context and sensing information. If context transition has occurred, types of needed sensors must be changed and each sensor modules need to turn on/off. In addition, excessive sensing has been found when the context decision is ambiguous. In this paper, we focus on power consumption associated with the context transition that occurs during indoor/outdoor detection, modeling the activities of the sensor associated with these contexts. And we suggest a freezing algorithm that reduces power consumption in context transition. We experiment with a commercial application that service is indoor/outdoor location tracking, measure power consumption in context transition with and without the utilization of the proposed method. We find that proposed method reduces power consumption about 20% during context transition.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.4
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• pp.89-108
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• 2010

Recently many mutual authentication protocol for light-weight hash-based for RFID have been proposed. Most of them have assumed that communications between a backend server and reader are secure, and not considered threats for backend server and RFID reader impersonation. In the real world, however, attacks against database or reader are more effective rather than attacks against RFID tag, at least from attacker's perspective. In this paper, we assume that all communications are not secure to attackers except the physical attack, and considering realistic threats for designing a mutual authentication protocol based on hash function. And It supports a mutual authentication and can protect against the replay attack, impersonation attack, location tracking attack, and denial of service attack in the related work. We besides provide a secure and efficient RFID mutual authentication protocol which resists impersonation attacks on all of the entities and alow a backend server to search tag-related information efficiently. We conclude with analyzing the safety and efficiency among latest works.

• Korean Journal of Heritage: History & Science
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• v.46 no.2
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• pp.26-45
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• 2013

Sudden increase exceeding 30million in the number of smart phone users, and rising interest in the technology of augmented reality, is now trying to combine it with AR technology in other areas very much. The field of cultural heritage, which has been constructed by the Internet and 3D technology, is not unusual and this field is now rapidly changing thanks to the AR technology which can make users experience cultural heritage with high reality. The Palaces in Seoul, however, use fragmentary tools of information - lack of heritage commentators, leaflet, etc, even though the number of visitors is gradually increasing. Therefore, three-dimensional and comprehensive cultural heritage information service is needed with the guidance in the mobile era. This study utilizes the AR technology for building the Deoksugung Tourist Information Service Application(App.) applying the markerless-based recognition technology which is a more advanced tool than the location-based AR technology. This new AR technology can switch perceived real images such as the tablet of the King in the Palace of in the real world, patterns and pedestals into virtual world, which can reproduce the damaged cultural assets as 3D. This also composes photos of the past with the current buildings, which can increase people's interest and absorption of the contents, and helps them understand and be aware of Korean traditional culture and cultural heritage effectively. In addition, convergence between IT new technology, Augmented Reality(AR) and humanities through storytelling based implementation of cultural heritage in smart phone is attempted to demonstrate that there is strength in which augmented reality technique exerts infinite creativity based on actual reality world.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.1
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• pp.1-7
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• 2008

Today, Korean medical community faces rapid changes in medical environment due to opening of medical market, more emphasis on making profit and introduction of private medical insurance. Therefore, it is apparent that around, major university hospitals, efforts are being made to adapt to such changes by establishing mid to long range strategic plans. We want to keep pace with changing times and diverse demand of patients by introducing state of the art system, utilizing Ubiquitous technologies for improvements. In doing so, we want to distinguish our hospital services from others. However, Hospital Information System that integrates ubiquitous technologies are introduced in limited basis due to problems like standardization and limits on medical use etc. Particularly, problems like absence of tag design suitable for medical environment, compatibility and extension issue with RFID system need to be addressed on application of RFID technologies. In order to solve such problems, this paper implemented RFID tag system, RFID-SIP UA program, location tracking program. This paper provides a comprehensive basic review of RFID and SIP model suggests the evolution direction of further advanced RFID application service. The design of RFID-SIP application offers advance RFID system with drawback and reduction search time of medical object. so there is a improvement of hospital information system in ubiquitous environment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.85-90
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• 2017

Indoor location-based services have been developed based on the Internet of Things technologies which measure and analyze users who are moving in their daily lives. These various indoor positioning technologies require separate hardware and have several disadvantages, such as a communication protocol which becomes complicated. Based on the fact that a reduction in signal strength occurs according to the distance due to the physical characteristics of the transmitted signal, RSSI technology that uses the received signal strength of the wireless signal used in this paper measures the strength of the transmitted signal and the intensity of the attenuated received signal and then calculates the distance between a transmitter and a receiver, which requires no separate costs and makes to implement simple measurements. It was applied calculating the value for the average RSSI and the RSSI filtering feedback. Filtering is used to reduce the error of the RSSI values that are measured at long distance.It was confirmed that the RSSI values through the average filtering and the RSSI values measured by setting the coefficient value of the feedback filtering to 0.5 were ranged from -61 dBm to - 52.5 dBm, which shows irregular and high values decrease slightly as much as about -2 dBm to -6 dBm as compared to general measurements.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.4
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• pp.24-35
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• 2011

This paper demonstrates a methodology of integrated operation and management system for intermodal connectivity center (ICC), which is planning to be build up as a large scale public transit facilities for green growth strategy by the national government. The ICC needs to be capable of providing the integrated location based information for the public transit users in terms of collaborating a variety of transit modes and complex facility in a large scale center. Recently, the upcoming information and communication technologies enable to come up with real time information provision on nomadic and portable devices, i.e. smart phones and/or tablet PCs, as what the users actually need to get on demand. In order to provide the public transit users in ICC with the integrated information on their smart phones for example, the integrated operation and management system plays a key role to collect the data utilizing the wireless communication with real time location tracking and to manage them to be effective and operational sources for applicable personalized services. Thus, this paper defines a type of services, subsystems, and relevant technologies for the system integration so called a "Smart Garatagi Service" and shows a filed test demonstration case in the existing airport terminal, Gimpo Domestic.