• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.41 no.3
• /
• pp.225-232
• /
• 2017

Several maintenance issues related to cavitation erosion and fatigue cracks in the water turbine subcomponents of pumped-storage plants, such as a runner and a draft tube, have been reported in the past. Generally, the pumped-storage plants provide ancillary services, such as black-start and system stabilization. The ancillary services are responsible for cyclic low opening operation of the guide vanes. It has been empirically established that this low opening operation further damages the water turbine subcomponents. In this study, the acceleration effect of the low opening operation on the cavitation erosion and fatigue of the water turbine is quantitatively assessed through finite element flow analysis, finite element stress analysis, and fatigue analysis. As a result of the assessment, it is identified that the cavitation potential increases and the turbine efficiency decreases with a decrease in the opening of the guide vane. Also, the low opening operation has an insignificant effect on the fatigue even though it increases the maximum stress values at the runner blade roots.

• Journal of Positioning, Navigation, and Timing
• /
• v.11 no.1
• /
• pp.51-58
• /
• 2022

Korea Augmentation Satellite System (KASS) is a Satellite Based Augmentation System (SBAS) system under development in South Korea and aims to provide air navigation services after 2023. In order to provide reliable service, detailed design for the operation of this system is required. This paper proposes a detailed operation-based designs based on mission, architecture, operation definition of the system. For the stable operation of the system, an operation organization was designed and operation activities were classified in consideration of the architecture and function of the system. Detailed operation procedures were designed according to this classification and operation procedures related to the command and configuration of subsystem were verified on the Integration, Verification and Qualification (IVQ) platform for integrated testing and verification. The proposed operation concepts and procedures will be continuously confirmed and verified during verification, qualification and service preparation, and will be updated event after official KASS service.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.61
• /
• pp.249-272
• /
• 2014

The purpose of this study is to seek the revitalization plans of export platform for supporting export enterprise of the domestic public services. To activate the export platform, alternatives to two aspects are required as follows. First of all, a governance plan of export platform should be established. At present, an operation entity of export platform, which is still developing stage, is not yet established. In this situation, even though export platform developed, it will faced with inefficient operation. Therefore, an operation entity and appropriate business model are important to the platform activation. second, to activate platform, it is necessary to support export process of life cycle. In particular, the service, which can support the business strategies setting and project implementation stage, is required. In addition, in order to activate the export platform is need to operate with he government's support program.

• Journal of the Korea Society for Simulation
• /
• v.12 no.4
• /
• pp.95-102
• /
• 2003

Stream servers are for supplying multimedia stream data to users through the internet such as movies and music without discontinuation. A typical stream server is designed roughly by considering the characteristics of stream services and by employing processors, memory, PCI bus, Ethernet, TOE and disks. This study focuses on deciding the priority for using resources such as PCI bus, buffer memory and TOE buffer, which have limited capacities in a typical stream server. When the priorities for using limited resources are not given properly, the stream servers may not even function as originally designed. The simulation study shows that the top priority for using PCI bus for normal streaming services should be given to the operation that sends data from buffer memory to TOE buffer. Giving priority for using PCI bus to other operation such as sending data from disks to memory results in a deadlock phenomenon.

• Proceedings of the Korea Society for Simulation Conference
• /
• 2003.11a
• /
• pp.67-74
• /
• 2003

Stream servers are for supplying multimedia stream data to users through the internet such as movies and musics without discontinuation. A typical stream server is designed roughly by considering the characteristics of stream services and by employing processors, memory, PCI bus, Ethernet, TOE and disks. This study focuses on deciding the priority for using resources such as PCI bus, buffer memory and TOE buffer, which have limited capacities in a typical stream server. The simulation study shows that the top priority for using PCI bus for normal streaming services should be given to the operation that sends data from buffer memory to TOE buffer Giving priority for using PCI bus to other operation such as sending data from disks to memory results in deadlock Phenomenon.

• Journal of the Korea Safety Management & Science
• /
• v.15 no.2
• /
• pp.135-141
• /
• 2013

As the country's elderly people who are 65 years or older recently exceeded 10% of the total population with development of medical technology and improvement of living standards, Korea has turned into an aging society. Especially in Gyeonggi-do, as of late December 2012, elderly people who were 65 years or older were 1,135,242 persons, taking up 18.98% of the region's population and registering the largest number of elderly people in the nation's cities or provinces. Due to such a sharp rise in elderly population, support for the elderly is increasing the burden on families and communities. The study aims to take as its subjects elderly people staying at authorized elderly welfare facilities, who are weak in mind and body and have difficulty in daily life with disabilities, or adult day care facilities that take care of elderly people during the day or at night, examine the concept of adult day care facilities and instances in foreign countries, and study the status of the adult day care facilities located in Gyeonggi-do, their services, and safety by figuring out space arrangement based on program implementation. Spacial arrangement in program operation should satisfy fuction and purpose from the manager and user's perspective, and a desirable program operation should provide separate spaces for the elderly with Alzheimer's and those without Alzheimer's. Compared to residential care facilities, adult day care facilities incur less financial burden and, compared to other authorized services, have many right functions that can upgrade the quality of users and satisfy their desires. Major countries like Japan, the UK, and Sweden recognize the right functions of day and night care services and aggressively support and utilize adult day care facilities. For adult day care facilities, quality services should be developed and use and choices should be enhanced as regards services. Development of special programs for the elderly with dementia and stroke, instead of simple protective functions of a program, must be actively promoted, while manpower training is required for program operation, conveniences, and safety. By developing and providing space arrangement models that focus on efficiency, convenience, and safety of program operation, adult day care operation can be revitalized, while quality of elderly care may be enhanced and welfare budget can be saved.

• Journal of Distribution Science
• /
• v.12 no.9
• /
• pp.65-72
• /
• 2014

Purpose - This study aims to provide a brief understanding of usability and its extended models with TAM as well as identifying additional determinants that had been suggested in previous studies on mobile services. Research design, data, and methodology - Empirical data were collected by conducting a field survey of potential mobile application service users. The call for participation was also made in mobile related application issues, which were widely discussed. Result - The ease of use and usefulness had a significantly positive influence on attitude and intention. It also was revealed that added value services can offer practical value to customers. Thus, positive attitudes toward the adoption of services by customers are present when they perceive higher usefulness and ease of use of mobile application services. Conclusion - It was indicated that customers who are more inclined to try new products or who have a higher demand for new things tend to think about those functionalities and added value mobile application services from the perspective of usefulness and ease of use and operation.

• Journal of Communications and Networks
• /
• v.18 no.4
• /
• pp.619-628
• /
• 2016

This paper describes a theoretical framework for rate allocation to maximize the power efficiency of overall heterogeneous wireless networks whose users are assumed to have multihoming capabilities. Therefore, the paper first presents a power consumption model considering the circuit power and radio transmission power of each wireless network. Using this model, two novel power efficient rate allocation schemes (PERAS) for multihoming services are proposed. In this paper, the convex optimization problem for maximizing the power efficiency over wireless networks is formulated and solved while guaranteeing the required quality of service (QoS). Here, both constant bit rate and variable bit rate services are considered. Furthermore, we extend our theoretical framework by considering the sleep-operation management of wireless networks. The performance results obtained from numerical analysis reveal that the two proposed schemes offer superior performance over the existing rate allocation schemes for multihoming services and guarantee the required QoS.

• Journal of Korean Institute of Industrial Engineers
• /
• v.35 no.4
• /
• pp.226-247
• /
• 2009

The competitiveness of the service sector is driven by its productivity. Services innovation is essential to enhancing service productivity. This paper first presents a framework for services innovation. The framework consists of three main phases of a service lifecycle (namely, service development, service operation, and service improvement), which are supported by IT infrastructure and service R&D management functions. This paper then identifies major research issues that should be investigated in the near future. The current issues of three representative service industries (namely, healthcare service, telecommunications service, and financial service) are also discussed.

• Journal of Korean Academy of Nursing
• /
• v.37 no.4
• /
• pp.613-623
• /
• 2007

Purpose: The purpose of this study was to describe the operation, staffing, and services provided at adult day care centers in Korea. Methods: The study was a cross-sectional descriptive survey. The subjects were 209 centers among 280 centers registered in Korea (response rate 74.6%). The data was collected from August to December in 2006. Results: 48.8% of centers were located in a city area. The centers were based on the Social Model 65.5% of the centers were open Monday to Friday, an average of $7{\sim}8$ hours per day Dementia, stroke or frail elderly could use the center, and 57.4% of centers were used for dementia and stroke elderly together. The enrollment of elderly was 13.5. The number of total staff was 8.27, the number of RN's and social workers was 0.67, and 2.54 respectively. The social services(Meal preparation 98.6%, Special event 98.1%, Transportation, 97.1%) were provided more than the health services(Physical therapy 98.1%, ADL training 95.2%, Counseling 84 7%, Vaccination 82.8%, Health monitoring 78.9%, Health education 78.5%, Bathing 66.1%, and Speech therapy 28.2%). Conclusion: These results suggest we have to develop a health-focused adult day health care model based on the needs of elderly and their families. Nurses will have an important role in adult day health care.