• ETRI Journal
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• 제38권1호
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• pp.149-158
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• 2016

In the field of augmented reality technologies, commercial optical see-through-type wearable displays have difficulty providing immersive visual experiences, because users perceive different depths between virtual views on display surfaces and see-through views to the real world. Many cases of augmented reality applications have adopted eyeglasses-type displays (EGDs) for visualizing simple 2D information, or video see-through-type displays for minimizing virtual- and real-scene mismatch errors. In this paper, we introduce an innovative optical see-through-type wearable display hardware, called an EGD. In contrast to common head-mounted displays, which are intended for a wide field of view, our EGD provides more comfortable visual feedback at close range. Users of an EGD device can accurately manipulate close-range virtual objects and expand their view to distant real environments. To verify the feasibility of the EGD technology, subject-based experiments and analysis are performed. The analysis results and EGD-related application examples show that EGD is useful for visually expanding immersive 3D augmented environments consisting of multiple displays.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.2099-2104
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• 2015

The paper presents a monitoring system for the cooling of distribution transformers. The suggested system is controlled by a microcontroller scheme. The system is designed to control the oil temperature. It gives a solution to improve the cooling system by adding a number of fans especially for indoor transformers that are placed in badly-ventilated rooms. Also, the paper includes an alarm system with the possibility of tripping the transformer if it is necessary. The monitoring system consists of acquisition temperature sensor, and on-site unit. The hardware and software of the on-site unit are demonstrated with sufficient illustrations. Small prototype is constructed in the laboratory. Some laboratory experiments are carried out for examining the designed circuit by using Proteus Virtual System Modeling as well as for testing the prototype monitoring system. Concerning this research point, a study is carried out to evaluate the economic feasibility. The results are recorded and associated with many recommendations that may be valuable to electrical distribution (utility) companies.

• 컴퓨터교육학회논문지
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• 제10권6호
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• pp.69-77
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• 2007

본 논문에서는 가상실험실 설계에 필수적인 전자계측장비의 주요기능을 자바애플릿을 이용하여 소프트웨어적으로 구현하였다. 구현된 가상전자계측장비는 가상아나로그 멀티미터, 가상신호발생기, 가상오실로스코프이며, 웹상에서 학습자가 간단한 마우스조작을 통해 가상실험이 가능하도록 하였다. 또한, 구현된 가상전자계측장비의 유효성을 입증하기 위해 주로 전자계측장비의 사용법에 대한 이해를 돕는 가상실험을 구성하였다. 가상아나로그 멀티미터는 OHM, ACV, DCV, DCA를 측정할 수 있는 4가지 실험이 구축되어 있고, 가상신호발생기의 경우 신호발생기에서 주로 다루는 주파수 값을 변화시키거나 삼각파, 구형파, 사인파를 발생시켜 가상오실로스코프로 확인할 수 있도록 하였다. 가상오실로스코프의 경우 두 개의 채널을 이용하여 측정할 수 있는 요소(전압, 전류)를 확대기능을 추가하여 좀 더 세밀하게 측정할 수 있도록 하였으며, 트리거, 커서, 파형의 합성등과 같은 여러 가지 유용한 기능들을 구현하였다. 구현된 가상전자계측장비는 자바클래스 형태로 구현하였기 때문에 가상실험실 구성형태에 따라 여러 가지 다양한 방법으로 활용이 가능하다.

• 한국자동차공학회논문집
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• 제21권2호
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• pp.26-36
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• 2013

Purpose of this study is to develop virtual components and environment for developing a controller of an Active Air Suspension System in laboratory that slough off existing development environment using real vehicle test. This paper presents an air spring modeling and analysis of air suspension system for a commercial vehicle. Preferentially, It was performed vehicle test for pneumatic system and an air spring for characteristic analysis of system. Each component of an air spring suspension system was developed through emulations and modeling of system for pressure and height sensors in the basis on test results in SILS environment. Non-linear characteristics of air spring are accounted for using the measured data. Also, pressure and volume relations for vehicle hight control is considered. After performance verification of virtual model was performed, we developed virtual environment based on HILS for an Active Air Suspension System. We studied estimation and verification technology for control algorithm that developed.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2008년도 학술대회 1부
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• pp.493-498
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• 2008

We proposed "Table Mediator" which is a tabletop system for digital storytelling that uses web-retrieved information for the students' educational field trip. Students can perform their storytelling for their virtual pre-field trip to build up a sequential path as a story with web-retrieved documents, satellite images, geographical information, and group discussion. The proposed system was designed to lessen the limitation of individual interaction such as restricted viewpoint and biased inclination by group digital storytelling. Local interactions also have the limitation such as insufficient information and knowledge and the system supplied the rich live information such as subjective critiques or recently discovered history, or new updates for building a story that makes users arrange their own idea as a consistent story to lessen the limitation of the local interactions. The system can be used for various applications such as travel, education and other collaborative works with group interaction.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권11호
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• pp.5588-5613
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• 2018

Virtualization technology has been widely applied in the area of computer security research that provides a new method for system protection. It has been a hotspot in system security research at present. Virtualization technology brings new risk as well as progress to computer operating system (OS). A multi-level perception security model using virtualization is proposed to deal with the problems of over-simplification of risk models, unreliable assumption of secure virtual machine monitor (VMM) and insufficient integration with virtualization technology in security design. Adopting the enhanced isolation mechanism of address space, the security perception units can be protected from risk environment. Based on parallel perceiving by the secure domain possessing with the same privilege level as VMM, a mechanism is established to ensure the security of VMM. In addition, a special pathway is set up to strengthen the ability of information interaction in the light of making reverse use of the method of covert channel. The evaluation results show that the proposed model is able to obtain the valuable risk information of system while ensuring the integrity of security perception units, and it can effectively identify the abnormal state of target system without significantly increasing the extra overhead.

• 복식문화연구
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• 제28권5호
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• pp.705-718
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• 2020

The goal of this study was to develop a haptic communication system that can convey the tactile sensation of fashion materials in a virtual environment. In addition, the effectiveness and how realistically the virtual fabric image of this system delivers the tactile sensation of actual fabric was verified. First, a literature review was conducted through which the tactile attributes of fashion materials were defined that would be implemented in the haptic communication system. Then, a questionnaire for evaluating the tactile attributes of fashion materials was developed. Next, a haptic communication system was designed to convey fashion image experiences in a virtual environment, from which a haptic rendering model was suggested. The effectiveness of the haptic communication system was evaluated by verifying user experiences with questions developed through a user evaluation experiment. The validity of the evaluation questions pertaining to the tactile attributes and the effects of the haptic communication system were verified. Factor analysis was conducted to verify the evaluation of the tactile sense attributes of the fashion material, which identified density, thickness, and elasticity of the material as key factors. As a result of comparisons between the tactile sense through haptic characteristics and through touching, it was observed that regarding density and thickness, tactile sense experience led to greater perceived reality, while this was not the case for elasticity.

• International Journal of Naval Architecture and Ocean Engineering
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• 제9권3호
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• pp.256-265
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• 2017

In this paper, an ascheme is proposed for multiuser underwater acoustic communication by using the multi-chirp rate signals. It differs from the well known TDMA (Time Division Multiple Access), FDMA (Frequency Division Multiple Access) or CDMA (Code Division Multiple Access), by assigning each users with different chirp-rate carriers instead of the time, frequency or PN code. Multi-chirp rate signals can be separated from each other by FrFT (Fractional Fourier Transform), which can be regarded as the chirp-based decomposing, and superior to the match filter in the underwater acoustic channel. VTRM (Virtual Time Reverse Mirror) is applied into the system to alleviate the ISI caused by the multipatch and make the equalization more simple. Results of computer simulations and pool experiments prove that the proposed multiuser underwater acoustic communication based on the multi-chirp rate exhibit well performance. Outfield experments carrie out in Xiamen Port show that using about 10 kHz bandwidth, four users could communicate at the same time with 425 bps with low BER and can match the UAC application.

• Journal of Power Electronics
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• 제10권6호
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• pp.611-620
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• 2010

This paper presents a new architecture, called "Power Electronics Remote Wiring and Measurement Laboratory (PermLAB)", that translates a common gateway interface (CGI) string from a remote web user to a web server connected to a 3-dimension switching matrix board, can be used to switch on and off, and to control a cluster of instruments and components. PermLAB addresses real-time connection, switching, and data acquisition over the Internet instead of using simulated data. A software procedure uses a signature system to identify each instrument and component in a complex system. The Web-server application is developed in HTML, JavaScript and Java, and in C language for the CGI interface, which resides in a controller portion of LabVIEW. The LabVIEW software fully integrates the Web sever, LabVIEW data acquisition boards and controllers, and the 3-dimensional switching matrix board. The paper will analyze a half-wave rectifier (AC - DC converter) circuit connected over the Internet using the PermLAB. PermLAB allows students to obtain real data by real-time wiring of real circuits in the laboratory using a "virtual breadboard" on the Web. The software for the Web-based 3-dimensional system is flexible, portable, can be integrated into many laboratory applications or expanded, and easily accessible worldwide.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.639-643
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• 2001

Recently, photovoltaic system has been studied widely as a renewable energy system, because it does not produce environmental pollution and it has infinity energy source from the sun. A study on photovoltaic system has a lot of problems like as reappearance and repetition of some situation in the laboratory experiment for development of MPPT algorithm and islanding detection algorithm, because output characteristics of solar cell are varied by irradiation and surface temperature of solar cell. And this system is consisted a lot of solar cell unit. Therefore, the assistant equipment which emulates the solar cell characteristics which can be controlled arbitrarily by researcher is require to the researchers for reliable experimental data. In this paper, the virtual implement of solar cell (VISC) system is proposed to solve these problems and to achieve reliable experimental result on photovoltaic system. VISC system emulates the solar cell output characteristics, and this system can substitute solar cell in laboratory experiment system. To realize the VISC, mathematical model of solar cell is studied for driving converter and the DC/DC converters are compared in viewpoint of tracking error using computer simulation. And then analysis of parallel and series characteristics was done for combination of VISC model.