• Journal of the Ergonomics Society of Korea
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• 제34권4호
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• pp.335-351
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• 2015

Objective: The aim of this study was to perform a usability test for CPAD (Cognitive Perceptual Assessment for Driving) and improve it based on the test results. Background: The cognitive perceptual assessment for driving is a computer-based assessment tool to assess the driving capacity of people with brain-damages. It may be a good tool for evaluating the brain-damaged drivers' safe driving capabilities and screening cognitive and perceptual deficits related to driving. We performed a usability test to improve the CPAD based on the result. Method: Both the software consisting of 8 sub-tests (depth perception, sustained attention, divided attention, stroop test, field dependency, digit span, trail making A, trail making B) and the hardware including the input and output devices ( joystick, mouse, keyboard, touch screen) were evaluated through user interviews. Also we identified the problems and issues in using them by observing the participants performing the CPAD tasks. Results: Based on the results, the task instructions were visually and auditorily improved and more practice examples were added to help the users understand the instructions better and increase the input accuracy, a response time window was added and the joystick and touch screen were simplified, which made it easier for the user to perform the CAPD tasks. Conclusion: User discomforts were minimized by improving the task environment, unless it had affected the evaluation criteria. Application: We plan to distribute the improved version of the CPAD to the regional rehabilitation hospitals, and the driving support centers for people with disabilities throughout the country, so it could be used as an evaluation tool for disabled drivers' cognitive and perceptual functions.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제18권2호
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• pp.33-48
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• 2018

In this paper, we characterise the joint interference alignment and power allocation strategies for a K-user multicell multiple-input multiple-output (MIMO) Gaussian interference channel. We consider a MIMO interference channel with a blind interference alignment through staggered antenna switching on the receiver. We explore the power allocation and the feasibility condition for cooperative cell-edge (CE) mobile users (MUs) by assuming that the channel state information is unknown. The new insight behind the transmission strategy of the proposed scheme is premeditated (randomly generated transmission strategy) and partial cooperative CE MUs, where the transmitter is equipped with a conventional antenna, the receiver is equipped with a reconfigurable multimode antenna (staggered antenna switching pattern), and the receiver switches between preset T modes. Our proposed scheme assists and aligns the desired and interference signals to cancel the common interference signals, since the received signal must have a corresponding independent signal subspace. The sum capacity for a K-user multicell MIMO Gaussian interference channel with reconfigurable multimode antennas is completely characterised.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제34권9A호
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• pp.673-678
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• 2009

This paper presents a feedback method for improving the system capacity of MU-MIMO system for downlink channel environments. In a typical conventional feedback method, CVQ, in order to enhance the channel capacity, not only the feedback load is increased but also the quantization of the channel vector is increased, because the channel parameter of each user has to be fed back after quantizing one of the pre-defined N-codebook vectors. In this paper, a novel feedback method is proposed which provides an improved system capacity by transferring the channel state information without increasing the feedback load. Performance of the proposed method is compared to the conventional CVQ method through computer simulations. The simulation results show that the proposed method with 3-bit feedback provides a system capacity comparable to the CVQ method of 6-bit feedback when the number of transmit antennas is 2.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제38A권9호
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• pp.744-749
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• 2013

We propose soft user data input on LDPC codes with parity encoded by the (1, 7) run length limited (RLL) code for perpendicular magnetic recording channel. The user data are encoded by maximum transition run (MTR) (3;11) code. In order to minimize the loss of code rate, the (1, 7) RLL code only encode the parity of LDPC. Also, to increase performance, we propose only user data part applied soft output Viterbi algorithm (SOVA). The performance using the SOVA showed good performance lower than 26 dB. In contrast, it showed worse performance high than 26 dB. This is because of incorrect soft information by high jitter noise and two different input types for LDPC decoder.

• Journal of Korea Society of Industrial Information Systems
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• 제24권5호
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• pp.129-137
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• 2019

Ubiquitous computing technology is emerging as information technology advances. In line with this, a number of studies are being carried out to increase device miniaturization and user convenience. Some of the proposed devices are user-friendly and uncomfortable with hand-held operation. To address these inconveniences, this paper proposed a virtual button that could be used in watching television. When watching a video on television, a camera is installed at the top of the TV, using the fact that the user watches the video from the front, so that the camera takes a picture of the top of the head. Extract the background and hand area separately from the filmed image, extract the outline to the extracted hand area, and detect the tip point of the finger. Detection of the end point of the finger produces a virtual button interface at the top of the image being filmed in front, and the button activates when the end point of the detected finger becomes a pointer and is located inside the button.

• Journal of the Society of Naval Architects of Korea
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• 제31권4호
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• pp.23-31
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• 1994

The compartmentation model is represented by the characteristics and geometric information of the spaces defined by the structural members which are used for the boundary planes of the compartment. For the efficient compartment modeling a program performing the compartmentation design by the chopping and merging method was presented by authors. In this research, the development of an interactive ship compartmentation modeller is introduced. It is natural that the value of the program lessens if the input process is complicated and uneasy, even though the internal techniques for the compartmentation modeling are superior. In this paper, a method for the convenient input is proposed and implemented with the help of a graphical user interface technique. The modeling method introduced in this paper performs an efficient compartmentation modeling fast and conveniently by the solid modeling concept and the graphical user interface.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• 제17권2호
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• pp.227-234
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• 2019

A user-friendly modeling interface is developed for a process-based total system performance assessment framework (APro) specialized for a generic geological disposal system for high-level radioactive waste. The APro modeling interface is constructed using MATLAB, and the operator splitting scheme is used to combine COMSOL for simulation of multiphysics and PHREEQC for the calculation of geochemical reactions. As APro limits the modeling domain to the generic disposal system, the degree of freedom of the model is low. In contrast, the user-friendliness of the model is improved. Thermal, hydraulic, mechanical and chemical processes considered in the disposal system are modularized, and users can select one of multiple modules: "Default process" and multi "Alternative process". APro mainly consists of an input data part and calculation execution part. The input data are prepared in a single EXCEL file with a given format, and the calculation part is coded using MATLAB. The final results of the calculation are created as an independent COMSOL file for further analysis.

• Journal of the Korea Institute of Information Security & Cryptology
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• 제19권5호
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• pp.175-188
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• 2009

Besides the passwords have low complexity, they can easily be revealed by the shoulder-surfing attack when they are inputted through the input devices such like keyboard. To overcome these problems, many new authentication schemes, which change the user secret different form or let users input their secrets through the more complex manners, have been suggested, but it is still hard to find the balanced point between usability and security. In this paper, we introduce a new authentication scheme that use the traditional alpha-numeric password as user secret based on operation of them on matrix. We show the security strength of our proposal through the analyses in the various aspects and confirm the difficulty that users feel from our proposal through the user study.

• Journal of Practical Engineering Education
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• 제15권3호
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• pp.641-647
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• 2023

In the fintech environment, ensuring secure financial transactions with smartphones requires authenticating the device owner. Smartphone authentication techniques encompass a variety of approaches, such as passwords, biometrics, SMS authentication, and more. Among these, password-based authentication is commonly used and highly convenient for user authentication. Although it is a simple authentication mechanism, it is susceptible to eavesdropping and keylogging attacks, alongside other threats. Security keypads have been proposed to address vulnerabilities in password input on smartphones. One such innovation is a group keypad, resistant to attacks that guess characters based on touch location. However, improvements are needed for user convenience. In this study, we aim to propose a method that enhances convenience while being resistant to eavesdropping and recording attacks on the existing group keypad. The proposed method uses new signs to allow users to verify instead of the last character confirmation easily and employs dragging-to-touch for blocking recording attacks. We suggest diverse positioning methods tailored for domestic users, improving efficiency and security in password input compared to existing methods.

• Journal of the Korea Computer Industry Society
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• 제4권12호
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• pp.901-910
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• 2003

Generally, most commercial retrieval engines adopt boolean query as user's query type. Although boolean query is useful to retrieval engines that need fast retrieval, it is not easy for user to express his demands with boolean operators. So, many researches have been studied for decades about information retrieval systems using natural language query that is convenient for user. To retrieve documents that are suitable for user's demands, they have to express their demands correctly, So, this thesis proposes interactive query process agent using natural language. This agent expresses demands concrete through gradual interaction with user, When users input a natural language Query, this agent analyzes the query and generates boolean query by selecting proper keyword and feedbacks the state of the keyword selected. If the keyword is a synonymy or a polysemy, the agent expands or limits the keyword through interaction with user. It makes user express demands more concrete and improve system performance. So, this agent can improve the precision of Information Retrieval.