• Journal of information and communication convergence engineering
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• v.1 no.2
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• pp.82-87
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• 2003

We are able to work on the shared virtual space in Web-based Collaborative Design System using only Internet and Web browser. Then the users will share 3D objects and must be able to pick the objects effectively which they want to manipulate. In this paper, picking is implemented not only by computing intersection of mouse pointer with the objects of the virtual world, but also by using capabilities and attributes of scene graph node, by setting bounds intersection testing instead of geometric intersection testing, by limiting the scope of the pick testing, using Java 3D. These methods can reduce the computation of picking and can pick 3D objects effectively and easily using the system of hierarchy.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.779-784
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• 2008

가상현실 시스템에서 체험자가 현실과 같은 몰입을 느끼기 위해서는 하드웨어를 통한 가상환경 구축과 체험자와의 상호작용이 중요하다. 본 논문에서는 위치 추적 시스템(Motion Tracking System), Wand(3D Mouse) 및 HoloPoint 등 다양한 VR 인터페이스를 통해 체험자의 움직임, 위치, 동작을 인식하고 대형 멀티 디스플레이 시스템을 통해 입체영상을 제공하는 가상환경을 구축하고 체험자가 원하는 정보를 상호작용(Interaction)으로 제공할 수 있는 가상 캠퍼스 안내 시스템을 구현하고자 한다. 가상 캠퍼스 구축은 캠퍼스의 지형, 건물 및 구조물들의 정확한 형상을 얻기 위해 3D 스캐너를 이용하였고 획득된 데이터는 일련의 과정들을 거쳐 3D 모델로 생성된다. 이렇게 생성된 모델을 재배치 및 최적화하기 위해 모델링 소프트웨어를 사용하였다. 구축된 가상 캠퍼스와 위치 추적 시스템 및 Wand의 연동을 위해 VR 프로그래밍 하여 체험자의 움직임 및 동작을 콘텐츠에 그대로 적용시켰다. 여기에 키오스크 유형의 HoloPoint를 이용하여 체험자의 손동작으로 상호작용하는 안내시스템도 구축하였다. 상호작용 가능한 가상캠퍼스 안내 시스템은 가상현실 시스템 구축에 대한 또 다른 방법과 활용 예를 제시함으로써 가상전시관 및 가상체험관 등에 활용될 수 있을 것으로 기대된다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.20-27
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• 2007

In this paper, we presents virtual lecture contents to study educational robots assembling focused on the beginners with little or no background about electronics. Considering the target students, we developed 'virtual laboratory' using flash animation and the students can assemble the robots virtually with mouse and keyboard. Also, the contents includes lectures about some basic electronics theories. electronic devices, and the electronics tools for the beginners. With the features described above, this contents would be useful for the beginners and elementary school students who want to assembling their own robots.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.854-861
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• 2005

The functional behavior of a portable consumer electronic (PCE) product is nearly all expressed with human-machine interaction (HMI) tasks. Although physical prototyping and computer aided design (CAD) software can show the appearance of the product, they cannot properly reflect its functional behavior. In this paper, we propose a virtual prototyping (VP) system that incorporates virtual reality and HMI functional simulation in order to enables users to capture not only the realistic look of a PCE product but also its functional behavior. We obtain geometric part models of the product and their assembly and kinematics information with the help of CAD and reverse engineering tools, and visualize them with various display tools. We adopt state transition methodology to capture the HMI functional behavior of the product into a state transition chart, which is later used to construct a finite state machine (FSM) for the functional simulation of the product. The FSM plays an important role to control the transition between states of the product. The proposed VP system receives input events such as mouse clicks on buttons and switches of the virtual prototype model, and it reacts to the events based on the FSM by activating associated activities. The VP system provides the realistic visualization of the product and the vivid simulation of its functional behavior. It can easily allow users to perform functional evaluation and usability testing. Moreover, it can greatly reduce communication errors occurring in a typical product development process. A case study about VP of an MP3 player is given to show the usefulness of the proposed VP system.

• International Journal of Computer Science & Network Security
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• v.21 no.12
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• pp.235-247
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• 2021

Today, the cloud computing has become a major demand of many organizations. The major reason behind this expansion is due to its cloud's sharing infrastructure with higher computing efficiency, lower cost and higher fle3xibility. But, still the security is being a hurdle that blocks the success of the cloud computing platform. Therefore, a novel Multi-tenant Decentralized Information Flow Control (MT-DIFC) model is introduced in this research work. The proposed system will encapsulate four types of entities: (1) The central authority (CA), (2) The encryption proxy (EP), (3) Cloud server CS and (4) Multi-tenant Cloud virtual machines. Our contribution resides within the encryption proxy (EP). Initially, the trust level of all the users within each of the cloud is computed using the proposed two-stage trust computational model, wherein the user is categorized bas primary and secondary users. The primary and secondary users vary based on the application and data owner's preference. Based on the computed trust level, the access privilege is provided to the cloud users. In EP, the cipher text information flow security strategy is implemented using the blowfish encryption model. For the data encryption as well as decryption, the key generation is the crucial as well as the challenging part. In this research work, a new optimal key generation is carried out within the blowfish encryption Algorithm. In the blowfish encryption Algorithm, both the data encryption as well as decryption is accomplishment using the newly proposed optimal key. The proposed optimal key has been selected using a new Self Improved Cat and Mouse Based Optimizer (SI-CMBO), which has been an advanced version of the standard Cat and Mouse Based Optimizer. The proposed model is validated in terms of encryption time, decryption time, KPA attacks as well.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.4
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• pp.857-869
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• 2016

It is a well-known fact that password based authentication system has been threatened for crucial data leakage through monitoring key log. Recently, to prevent this type of attack using keystroke logging, virtual onscreen keyboards are widely used as one of the solutions. The virtual keyboards, however, also have some crucial vulnerabilities and the major weak point is that important information, such as password, can be exposed by tracking the trajectory of the mouse cursor. Thus, in this paper, we discuss the vulnerabilities of the onscreen keyboard, and present hypothetical attack scenario and a method to crack passwords. Finally to evaluate the performance of the proposed scheme, we demonstrate an example experiment which includes attacking and cracking by utilizing password dictionary and analyze the result.

• Journal of Digital Contents Society
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• v.18 no.1
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• pp.1-7
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• 2017

Virtual reality(VR) is known as immersive multimedia or computer-simulated reality, is a computer technology that replicates an environment, real or imagined, and simulates a user's physical presence and environment to allow for user interaction. Virtual realities artificially create sensory experience including sight, touch, hearing, and smell. Owing to the use of a single device in most VR contents, user have difficulty in manipulating user interface and game object. And also immersion of the game goes down because they can't see the mouse and keyboard in virtual space. In this paper, we design and implement the chess game to easily and accurately control user interface to improve the immersion in game.

• Science of Emotion and Sensibility
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• v.13 no.4
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• pp.789-796
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• 2010

The purpose of this study was to test a large screen and rear-projected virtual reality (VR) interface in color choice for environmental design. The study piloted a single three-dimensional model of a bedroom including furniture in different color combinations. Using a mouse with an $8'{\times}6'$ rear-projector screen, participants could move 360 degree motion in each room. The study used 34 college students who viewed and interacted with virtual rooms projected on a large screen, then filled out a survey. This study aimed to understand the interaction between the users and the VR interface through measurable dimensions of the interaction: interest and user perceptions of presence and emotion. Specifically, the study focused on spatial presence, topic involvement, and enjoyment. Findings should inform design researchers how empirical evidence involving environmental effects can be obtained using a VR interface and how users experience the interaction with the interface.

• Journal of Broadcast Engineering
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• v.22 no.1
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• pp.87-94
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• 2017

This paper presents a prototype for virtual reality operating system (VR OS) concept with head mount display (HMD) and hand gesture recognition technology based on game engine (Unity3D). We have designed and implemented simple multitasking thread mechanism constructed on the realtime environment provided by Unity3D game engine. Our virtual reality operating system receives user input from the hand gesture recognition device (Leap Motion) to simulate mouse and keyboard and provides output via head mount display (Oculus Rift DK2). As a result, our system provides users with more broad and immersive work environment by implementing 360 degree work space.

• Journal of KIISE:Software and Applications
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• v.36 no.12
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• pp.1028-1033
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• 2009

This paper presents a real-time hand gesture recognition approach for controlling a computer. We define hand gestures as continuous hand postures and their movements for easy expression of various gestures and propose a Two-layered Bayesian Network (TBN) to recognize those gestures. The proposed method can compensate an incorrectly recognized hand posture and its location via the preceding and following information. In order to vertify the usefulness of the proposed method, we implemented a Virtual Mouse interface, the gesture-based interface of a physical mouse device. In experiments, the proposed method showed a recognition rate of 94.8% and 88.1% for a simple and cluttered background, respectively. This outperforms the previous HMM-based method, which had results of 92.4% and 83.3%, respectively, under the same conditions.