• Archives of design research
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• v.13 no.2
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• pp.103-109
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• 2000

Rapid prototyping technology has been widely applied to the design process in the industry. This technology made it easy to generate a prototype which acts like a real product in logic. However, this technology has not been validated sufficiently as a usability test method. The purpose of this study was to test the hypothesis : There was no significant difference between a real product and its prototype. An experiment was designed to test it statistically. a microwave oven was selected and its prototype was generated using a rapid prototyping tool. Six subjects used the microwave oven and another six subjects used the prototype to perform five scenario tasks. As a result, there was significant difference between the real product and prototype in success rate, task completion time, and number of buttons pressed. The prototype was more difficult to operate than the real product. Therefore we should be careful when we apply rapid prototyping. technology. In the discussions, the causes of the difference were identified and some guidelines were suggested for who wants to apply rapid prototyping tool to the usability test.

• Journal of Korea Multimedia Society
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• v.7 no.11
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• pp.1610-1619
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• 2004

While researches and studies on short distance wireless communications have been actively carried out, studies on many applications of short distance wireless communications focusing on user-oriented Mobile device are also in progress. Since Bluetooth has several advantages that existing short distance communication does not have, studies on standardization have been carried out focusing on SIG, and IEEE has also jointly studied on this. Bluetooth is a short distance wireless communication technology that can be usefully applied to various kinds of applications. In this regard, this thesis presents payment system using Bluetooth, out of several application technologies of Bluetooth. This payment system is based on the scenario in which secure piconet is formed focusing on the user, the user gets in the car, fill up the gas at the gas station using his own Mobile device and pay The secure payment system presented in this thesis is designed to complement the weakness of existing Bluetooth in terms of security and to secure several requirements of security required for payment using short distance wireless communication.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.2
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• pp.293-303
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• 2017

FIDO(Fast IDentity Online) technology is expanding very rapidly which can replace traditional password-based authentication with biometrics technology[1,7]. FIDO provides convenient authentication with biometrics technology and secure key management with smart card technology, but it does not provide user identification, thus traditional user identification technology should be used before a FIDO device is registered to a FIDO server. K-FIDO[3] is an approach to implement FIDO and certificate-based authentication technology into a single device that user can utilize certificate-based authentication in initial registration of FIDO device to FIDO server. It is expected that very shortly users will own and use multiple K-FIDO devices. If we consider the traditional approach of copying single certificate to multiple devices or issuing independent certificate to each device, there will be many complex problems. In this paper we propose more secure and convenient key management technology in multiple K-FIDO device scenario using self-extended certification[4].

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.3B
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• pp.189-203
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• 2012

In cognitive radio networks, a secondary user opportunistically accesses an empty channel based on periodic sensing results for avoiding possible interference to the primary users. However, local sensing does not guarantee the full protection of the primary users because hidden primary receivers may exist within the interference range of the secondary transmitter. To protect primary systems and simultaneously to maximize utilization of the secondary users, we need to derive carefully designed coexistence solutions for various network scenarios. In this paper, we propose coexistence conditions without any harmful interference in accordance with the uplink/downlink schedule and user position. We have classified the coexistence conditions into four different scenario cases depending on the provided information to the secondary network basestations. Computer simulation results demonstrated that the proposed method can be applied to the real cognitive radio system to improve the communication probability of CR devices.

• The Transactions of the Korea Information Processing Society
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• v.5 no.12
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• pp.3063-3076
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• 1998

To facilitate presentations of various media and transfer their implicit meaning efficiently, needed are effective development techniques for representing and manipulation temporal and spatial informations between multimedia data. Especially, these emporal and spatial informationsl are so deeply related with each other that it is required to have the integrated mehod for their representation. This paper suggests the Presentation Synchronization Trdd(PST) which represents their temporal and spatial informationsl and the efficient presentation model as traversing this PST. In this model, without knowing the specific user's interface or any script languages, the user can write the presentation scenario only based on allen's tecporal specification. This model has a characteristic of allowing user's inputs that may dynamically modify the presentation sequence in presentation time. As through the renmining steps of consistency checking for their relations. PST generation, and PST traversing step, this model provides users with simple and effective presentation of multimedial data by having them be presented auton\matically.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.4 no.1
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• pp.43-51
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• 2010

In this paper, we developed a digital Taekwondo trainer system based on the electronic protector was authorized by the World Taekwondo Federation for the improvement of user's training effects and athletic performances. Our system consists of E-Kick Bag with sensors for sensing hits, taekwondo trainer program and receiver for interconnection of E-kick Bag to program. Taekwondo trainer system also has an advantage to improve training effects and athletic performances such as hit-accuracy and reaction velocity by appointing a hitting target for users with 6 LED indicators. The taekwondo trainer program is a user interface to provide training courses such as progress training of response time and stamina, preparation training for real sparring by training scenario. It has also characteristics which are to strengthen and supplement user's pros and cons by analyzing hitting intensity and accuracy from training. In this paper, we implemented a test targeting eight taekwondo players on the playing list include a member of the Korea national team and conducted a survey in order to evaluate the utility of our system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.32-42
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• 2015

In this paper, we considered the scenario that one cellular link and muti-D2D links share the same frequency resource which can improve the spectrum efficiency during uplink communication in LTE (Long Term Evolution)-Advanced network. In order to reduce the interference caused to the D2D users, we set DME (Discovery and Management Entity) which can send the area information to eNB(evolved Node B). We proposed a resource allocation scheme by using these assistant devices to reduce the interference that CUE (Cellular User Equipment) causes to DUE Rx (D2D UE Receiver). Basing on the area information, in order to mitigate the interference among the D2D pairs which share the same frequency resource, a power control scheme has been proposed. The simulation results prove that by using the DMEs, the proposed schemes improve the stability of D2D communication and bring the highest performance of the communication system when comparing to the other different schemes.

• Smart Media Journal
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• v.5 no.2
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• pp.42-50
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• 2016

In case of a emergency situation or a natural disaster, a warning notification system is an essential tool to notify at-risk people in advance and provide them useful information to survive the event. Although some systems have been proposed such as emergency alert system using android, SMS, or P2P overlay network, these works mainly focus on a reliable message distribution methods. In this paper, we proposed a novel design and implementation of a personalized warning notification system to help inform not only the at-risk people but also their family and friends about the coming disaster as well as escape plan and survival information. The system consists of three main modules: the user selection module, the knowledge based message generator, and message distribution modules. The user selection module collects the list of people involved in the event and sorts them based on their level of involvement (their location, working position and social relationships). The knowledge based message generator provides each person with a personalized message that is concise and contains only the necessary information for the particular person based on their working position and their involvement in the event. The message distribution module will then find a best path for sending the personalized messages based on trustiness of locations since network failures may exist in a disaster event. Additionally, the system also have a comprehensive database and an interactive web interface for both user and system administrator. For evaluation, the system was implemented and demonstrated successfully with a building on fire scenario.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.6
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• pp.1509-1522
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• 2018

The purpose of this study is to support flexible authentication functions in various services using various types of user information. Rather than requiring the same level of authentication for all services, the goal is to identify the level of authentication at the time of user authentication and to increase convenience and efficiency by dynamically granting authority. In this paper, we propose POSCAL (Protocol of Service Control by Authentication Level) protocol which can control service access based on various local authentication information. To verify the function of the authentication framework, we developed the electronic wallet service based on the POSCAL authentication framework and evaluated the implementation function based on the use case scenario. The proposed protocol satisfies user and message authentication, confidentiality of authentication information, integrity of authentication history, non - repudiation of authorization, and access control by service according to security level.

• Journal of Platform Technology
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• v.9 no.3
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• pp.70-77
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• 2021

The purpose of Serious games in immersive Metaverse platform to provide users both fun and intriguing learning experiences. We proposes a serious game for self-trainable fire evacuation drill with collaboration among avatars synchronized with multiple trainees and optionally with real-time supervising placed at different remote physical locations. The proposed system architecture is composed of wearable motion sensors and a Head Mounted Display to synchronize each user's intended motions to her/his avatar activities in a cyberspace in Metaverse environment. The proposed system provides immersive as well as inexpensive environments for easy-to-use user interface for cyber experience-based fire evacuation training system. The proposed configuration of the user-avatar interface, the collaborative learning environment, and the evaluation system on the VR serious game are expected to be applied to other serious games. The game was implemented only for the predefined fire scenario for buildings, but the platform can extend its configuration for various disaster situations that may happen to the public.