• Journal of Information Technology Applications and Management
• /
• v.14 no.4
• /
• pp.221-233
• /
• 2007

Which factors should influence consumer consideration to subscribe to Voice over Internet Protocol (VoIP)? Policy issues, managerial concerns, and demographic variables are possible factors. This paper discusses policy and managerial issues regarding VoIP adoption. A model that explains VoIP adoption is proposed and tested. This study analyzes a survey of 750 prospective VoIP users in Korea. The testing is accompanied by logistic regression and discriminant analysis. The results show that trust in VoIP, relative comparison of Quality to fixed service, numbering plan, satisfactions of call Quality and customer services on both fixed and mobile services have impacts on the adoption of VoIP. Implications for VoIP providers and policy makers are presented.

• Journal of Digital Convergence
• /
• v.6 no.1
• /
• pp.75-82
• /
• 2008

This paper is aimed to exam factors in the perceived service quality of web portal site and to analyze their effects on customer satisfaction. And this paper analysis satisfaction effects on revisit intention. To accomplish this purpose, this study examined previous studies and summarized core factors of service quality. Form literature survey, we drawn core factors. They are convenience, technologies, valuable of contents and service, communication, positioning. These core factors will affect on customer trust, satisfaction and satisfaction will affect on revisit intention. This study examined previous studies and summarized core factor in perceived service quality of web portal site. Fourteenth hypothesis were developed. Data for empirical testing were collected through survey to portal sites user. The results of this study are as follows; First, we find that service, communication and positioning have positive influence on the trust. Second, convenience, valuable of contents and postioning factors have a positive influence on the satisfaction. Third, it is shown that satisfaction have a positive influence on the revisit intention.

• Korean Parent-Child Health Journal
• /
• v.9 no.2
• /
• pp.101-115
• /
• 2006

Purpose: The purpose of this paper is to describe the development of health educational program for maternity using principle of user centered design. Method: Research process includes five distinct phases: needs assessment, analysis, design, development/testing/revision, and application release. Results: This program includes an introduction, pregnancy test and fetal assessment, maternal and fetal change during pregnancy, self-care methods during pregnancy, complication of postpartum period, process of labor, complication of pregnancy, self care during the postpartum period, information for parenting skill, father page, FAQ, helping resources and institutions. Conclusion: The program will be distributed to health centers for maternal health education. The second phase of this project was evaluation this program for further development of the program. The end result of this program will be pregnant women with a high degree of usability. Author believe this program have true potential in helping maternal health promotion and successful parenting.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.11 no.4
• /
• pp.129-141
• /
• 2015

This study evaluates user experience of streaming stick service through usability testing. Streaming stick services such as Roku, Chromecast, and Everoncast were tested in ten levels belonging to five usability variables that are composed of efficiency of use, accuracy, meaningfulness, flexibility, and consistency. Each variable has two levels respectively that are responsiveness, minimal action, error prevention, error detection, error recovery, understandability, learnability, substitutivity, predictability, and familiarity in order. Twenty five participants volunteerly joined this research, and the results showed that Roku is superior to another two OTTs in most levels and variables. It implies that participants prefer to remote control, many channels, and personalized service during experiencing the service.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.6 no.2
• /
• pp.183-191
• /
• 2010

Decision problem called an optimal release policies, after testing a software system in development phase and transfer it to the user, is studied. The applied model of release time exploited infinite non-homogeneous Poisson process. This infinite non-homogeneous Poisson process is a model which reflects the possibility of introducing new faults when correcting or modifying the software. The failure life-cycle distribution used mixture which has various intensity, if the system is complicated. Thus, software release policies which minimize a total average software cost of development and maintenance under the constraint of satisfying a software reliability requirement becomes an optimal release policies. In a numerical example, after trend test applied and estimated the parameters using maximum likelihood estimation of inter-failure time data, estimated software optimal release time.

• Convergence Security Journal
• /
• v.8 no.4
• /
• pp.121-126
• /
• 2008

It is of great practical interest to decide when to stop testing a software system in development phase and transfer it to the user. This decision problem called an optimal release policies. In this paper discussed to specify an optimal release policies. In this paper, propose an optimal release policies of the life distribution applied Erlang distribution of special pattern of Gamma distribution. In this paper, discuss optimal software release policies which minimize a total average software cost of development and maintenance under the constraint of satisfying a software reliability requirement. From Sensitivity Analysis, make out estimating software optimal release time.

• Journal of Institute of Control, Robotics and Systems
• /
• v.16 no.5
• /
• pp.498-509
• /
• 2010

In this paper, a waypoint guidance law Line Tracking algorithm is designed for testing an Unmanned Airship. In order to verify, we develop an autonomous flight control and test system of unmanned airship. The flight test system is composed FCC (Flight Control Computer), GCS (Ground Control System), Autopilot & Guidance program, GUI (Graphic User Interface) based analysis program, and Test Log Sheet for the management of flight test data. It contains flight test results of single-path & multi-path following, one point continuation turn, LOS guidance, and safe mode for emergency.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.19 no.1
• /
• pp.10-18
• /
• 2007

The purpose of this study is to develop an user-friendly computer program which can analyze the thermal performance of high-rise curtain wall. In this study, the sub-routines for FVM SOLVER, HIGH-RISE CONDITION CALCULATION, AUTOMATIC SPECIFICATION BOUNDARY/MESH, MATERIAL DATABASE, and GRAPHICAL CONDENSATION/U-FACTOR OUTPUT were developed by using Visual Basic. The curtain wall heat conduction simulation results of program showed good agreement with those of FLUENT and THERM. The minimum and maximum relative error rates were 3.17 and 9.68% compared to other software.

• Journal of Electrical Engineering and Technology
• /
• v.2 no.1
• /
• pp.29-34
• /
• 2007

The input and output impedances in a low voltage distribution system is one of the most important matters for power line communication because from the viewpoint of communication, the attenuation characteristic of the high frequency signals is greatly caused by impedance mismatch during sending and receiving. The frequency range is from 1MHz to 30MHz. Therefore, this paper investigates the input and output impedances in order to understand the characteristic of high frequency signals in the low voltage distribution system between a pole transformer and an end user. For power line communication, the model of Korea's low voltage distribution system is proposed in a residential area and then the low voltage distribution system is set up in a laboratory. In the low voltage distribution system, S parameters are measured by using a network analyzer. Finally, input and output impedances are calculated using S parameters.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2006.05a
• /
• pp.139-142
• /
• 2006

Numerous simulation studies and researches have recently revealed the rapid development and evolution in the emerging area of intelligent unmanned aerial vehicle (UAV). This study aims to develop a flight performance evaluation about the wireless unmanned helicopter. The process includes the design and testing of flight hardware and software that interprets sensor data. For the unmanned helicopter used in this research, an inertial sensor that provides posture (roll, pitch and yaw angles) and a Bluetooth is used to provide wireless connection between the user's pc and the helicopter were installed in the helicopter the helicopter's pitch, roll and yaw were the communication data. The accuracy of the system was confirmed by a computer simulation. The software also has been developed to support operators and displays helicopter position and posture by graphics.