• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.23 no.4
• /
• pp.117-124
• /
• 2015

RAM (Reliability, Availability and Maintenance) has been applied to design and analysis tools which affects system's operational sustainability and its life cycle cost as RAM-c(2009 DoD). RAM-c plays also an important role to guarantee the system engineering for mission assurance. Reliability is highly related to the probability of system failure. Availability means mission capability or the condition of ready to mission. Maintenance includes both the repair to recover the system in the event of failure/unexpected breakdown and proactive maintenance to prolong the design service life of the system or machinery. It is the purpose that this paper is to analyze and conclude the objective service life of UAV. The more UAV is operated, the less the level of its reliability becomes. Repairing failures and supplying spare parts on time, system reliability could be improved up until the time over target. Applying statistical Weibull distributions, this paper suggests the analysis of the design service life and economic life of UAV based on RAM-c with operational data.

• Journal of KIISE:Software and Applications
• /
• v.34 no.3
• /
• pp.219-225
• /
• 2007

UPnP AV Framework automatically integrates and manages various AV devices that are connected to network as an important component in home network. Therefore, user can access and control AV contents at any time. But, other existing home entertainment systems target multimedia service support that is based on multimedia home server system. In this paper, we propose an integrated home entertainment system (u-MUSE system) that supports remote control service. It can manage application in remote AV device or control AV contents directly in home network environment. The proposed system sufficiently performs role of control center for electronic devices in home via integrated system control and AV contents playback service.

• 한국정보통신설비학회:학술대회논문집
• /
• 2005.08a
• /
• pp.141-145
• /
• 2005

In this paper, UWB system did research about effect that interference effect with neighborhood single equipment or nearby group equipment gets In DMB service. 2.6425GHz satellite digital multimedia broadcasting service(SDMB) that electric wave interference special quality is contiguity frequency-band including interference of signal by unnecessary radiation level that is radiated in UWB system, and 3.4125GHz broadcasting relay net that is In-band frequency-band and interference effect degree that get in service did comparative analysis. SDMB system was BER $1{\times}10^{-4}$ that interference effect happens from 6.5m point and broadcasting signal reception is possible at 4m point. Also, it was BER $1{\times}10^{-4}$ that interference effect begins to happen from 5.0m point about center frequency 3.4126GHz and broadcasting signal reception is possible at 2m point. And, confirmed that UWB system of impulse method is less interference effect about 2 dB than UWB system of OFDM method, to electric wave of UWB system that is small output

• Journal of Information Processing Systems
• /
• v.1 no.1 s.1
• /
• pp.96-101
• /
• 2005

Spotlighted as an innovative information technology environment, ubiquitous computing has been actively researched on recently. Especially, domestic and global researches focus on the RFID system, which is being eyed to replace the existing bar-code system. As an essential technology for ubiquitous computing, the RFID system can be applied for various purposes. The security issues of the RFID system focus on how the low-priced tag type could have reasonable price competitiveness. The Auto-ID Center in the U.S. is spearheading the research on distribution service and omni-directional security. As for Japan, the researches on omni-directional security and EPC application are necessary in securing the technology for ubiquitous computing with support from the Ministry of Public Management Home Affairs, Posts, and Telecommunication. In this paper, a method of ensuring the availability of the RFID system service will be presented based on the ubiquitous computing environment with the existing omni-directional security and user-friendly interface. While the existing researches focus on the RF reader system and tag-based security, this paper's suggestion also considers the availability of a sen ice to suggest ways of increasing the practical usage of a low-priced RF tag.

• Journal of the Korean Society for Library and Information Science
• /
• v.53 no.4
• /
• pp.361-372
• /
• 2019

The Overseas Construction Engineering Information System (OVICE), which is operated by the Korea Institute of Construction Technology, uses the Overseas Construction Information Service classification system to service information required for overseas construction of domestic construction engineering companies. In this study, through the application of the recommendation system using collaborative filtering, identifying the relationship between the subjects for real users, verifying the adequacy of the overseas construction information classification system currently in service. Through this, I would like to propose an information service classification system that reflects actual user demand.

• Journal of Positioning, Navigation, and Timing
• /
• v.11 no.4
• /
• pp.229-238
• /
• 2022

This paper addresses on the International technical trends, standards, and development status of terrestrial radionavigation system to provide more accurate and fail-safe Positioning, Navigation, and Timing (PNT) Information available in maritime navigation environment. We analyze the performance result of pilot service in enhanced Long range navigation (eLoran) testbed environment using Low Frequency (LF) signal, and describe the development status of Ranging-Mode (R-Mode) system using Medium Frequency (MF) and Very High Frequency (VHF) to meet the Harbor Entrances and Approaches (HEA) requirement of International Maritime Organization (IMO) within 10m position accuracy. Furthermore, we present an architecture for integrated service of satellite-terrestrial navigation system and future maritime applicable fields. As the core information infrastructure of future navigation for 4th industrial revolution, this paper will be contributed to determining the direction of present and future to provide fail-safe PNT service with Global Navigation Satellite System (GNSS) based on the technical enhancement of terrestrial integrated navigation system.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.5
• /
• pp.3-9
• /
• 2015

The wireless communication system adopts an appropriate retransmission scheme on each system protocol layer to improve reliability of data transmission. In each system protocol layer, the retransmission scheme operates in independently other layers and operates based on the parameters without reference to end-to-end performance of wireless communication system. For this reason, it is difficult to design the optimal system parameters that satisfy the QoS requirements for each service class. Thus, the performance analysis of wireless communication system is needed to design the optimal system parameters according to the end-to-end QoS requirements for each service class. In this paper, we derive the mathematical model to formulate the end-to-end performance of wireless communication system. We also evaluate the performance at the MAC and transport layers in terms of average spectral efficiency and average transmission delay. Based on the results of performance evaluations, we design the optimal system parameters according to the QoS requirements of service classes. From the results, the HARQ combined with AMC is appropriate for the delay-sensitive service and the ARQ combined with AMC is appropriate for a service that is insensitive to transmission delay. Also, the TCP can be applied for the delay-insensitive service only.

• The Journal of Information Technology
• /
• v.2 no.2
• /
• pp.69-88
• /
• 1999

Only service organizations providing service quality above customers' anticipations have survived and developed in hyper competitive environment. These organizations are more dependent on their customer-contact service employees than those providing tangible products, because of the characteristics of service, intangibility, inseparability, heterogeneity, and perishability. But few researches focused on the efficient managements or controls of service organizations in this context. Therefore, author aimed at understanding of the determinants of service organizations' control system(i.e., characteristics of service), service employees' reaction on control types(i.e., service employees' role stress), and their performance(perceived service quality by customers). First the concepts of service quality and control systems are described. Specially, author explained the differences between service quality and service satisfaction or service attitude, and the control system types and their fundamental ideologies. Second, some propositions are provided according to integrated framework developed in this paper: (1)control types according to the characteristics of service, (2)influences of control systems on employees' reactions and (3)perceives service quality by the customers, and (4)relationships between the reactions and the service quality. This paper concludes with a summary, a discussion of theoretical and managerial implications, and several suggestions for future directions.

• The KIPS Transactions:PartD
• /
• v.15D no.3
• /
• pp.411-420
• /
• 2008

This paper implemented the u-Healthcare Context Information System (HCIS) supporting ubiquitous healthcare by using location, health and titrating environment information collected from sensors/devices equipped in home for healthcare home service. The HCIS is based on the Distributed Object Group Framework (DOGF), a management model which can customize distributed resources, and manages various context information, applications and devices as a group in healthcare home environment, as one more logical units. Also, this system provides continuous healthcare multimedia service considering a resident's location using Mobile Proxy, and the healthcare context information through Context Provider to a resident in home. For verifying execution of our system, we implemented the seamless multimedia service based on resident's location and the prescription/advice and schedule notification/alarm service as healthcare applications in home. And we showed the executing results of healthcare home service by using service device existed in the residential space on which the resident is located according to the healthcare scenario.

• Journal of KIISE:Computer Systems and Theory
• /
• v.34 no.5_6
• /
• pp.214-227
• /
• 2007

A context-aware service in ubiquitous computing environments aims to supply services according to users' situation information that is dynamically occurring. The existing context-aware workflow systems, such as FollowMe and uFlow, provide context-aware services based on a workflow, which uses users' situation information as transition conditions of a service. But they can't apply users' new service demands, which may dynamically occur even when a workflow is on going, to a workflow scenario. In this paper we propose a context-aware workflow system, which can reapply users' new service demands into an initial workflow without interrupting or deleting the workflow. The proposed system can provide context-aware services without interrupting of service by recognizing exactly a place holder that has to be changed in a workflow scenario and by reconstructing only the changed parts through an incremental parsing method. Therefore, a user can immediately apply his new service demands to an on-going workflow scenario, and he can be guaranteed continuous executions of context-aware services according to a workflow scenario, which includes new service demands.