• IEMEK Journal of Embedded Systems and Applications
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• v.13 no.5
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• pp.253-259
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• 2018

Recently, small satellite industries are rapidly changing. Demand for high performance small satellites is increasing with the expansion of Earth Observation Satellite market. A next-generation small satellites require a higher resolution image storage capacity than before. However, there is a problem that the HW configuration of the existing small satellite image storage device could not meet these requirements. The conventional data storing system uses SDRAM to store image data taken from satellites. When SDRAM is used in small satellite platform of a next generation, there is a problem that the cost of physical space is eight times higher and satellite price is two times higher than NAND Flash. Using the same satellite hardware configuration for next-generation satellites will increase the satellite volume to meet hardware requirements. Additional cost is required for structural design, environmental testing, and satellite launch due to increasing volume. Therefore, in order to construct a low-cost, high-efficiency system. This paper shows a next-generation solid state recorder unit (SSRU) using MRAM and NAND Flash instead of SDRAM. As a result of this research, next generation small satellite retain a storage size and weight and improves the data storage space by 15 times and the storage speed by 4.5 times compare to conventional design. Also reduced energy consumption by 96% compared to SDRAM based storage devices.

• Journal of Information Technology Services
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• v.9 no.4
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• pp.243-259
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• 2010

It is expected that the next generation mobile communication system will be a service-driven developed system capable to realize the human-centric mobile convergence services. and it is different from the technology-driven development approach of the second and the third generation mobile communication systems. As a preliminary research work on such service-driven system development approach for the next generation mobile communication system. we developed the scenario based service analysis process (2SAP) framework to derive core service technologies and functionalities. In this paper. we propose the next generation mobile convergence service business model creation methodology based on research results of the 2SAP framework. To achieve this goal, we first establish a service model contains several components such as infrastructures. operations. and provision of services that are indispensible for providing next generation mobile services. Then, the next generation mobile services and its corresponding business models can be created by adding service and value flows to the developed service model after defining necessary components of business model including actors, their relationships, and roles.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.241-243
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• 2002

Recently, great efforts are concentrated on the autonomous, adaptive protection schemes with advanced artificial intelligence and digital technology. It is highly required for a next generation protective system not only to detect and to clear a fault, but also to fit itself to the changing environment. In this paper it is suggested an evaluation method for the protection ability of a protective system in a distributed system. The suggested method is of bottom-up scheme, in other words, protection ability is estimated from the lowest level of parameters in each protective devices to the highest level of the whole protective system. This feature makes it possible to evaluate the protection ability either for the protective device(or a system), or for a protected system. And, in addition, it is enabled that the protectability concept can be applied in the design stage of a protective system for a distribution network. The proposed method is applied to a simple distributed network to show its effectiveness.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.434-439
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• 2002

The researches on the direct drive system, which directly transfers axle load of the traction motor to wheels, have been developed as a next generation drive system in Japan and Europe. As a result of excluding couplings and gear units, the direct drive system has advantages on the bogie mount space to be smaller sized, lower noisy, more efficient and less weighted than the conventional drive system - indirect drive system. Since the simplification of the direct drive system design depends on the design of the traction motors, the researches on the direct drive system with focusing on the traction motors get started. The advantages/disadvantages of direct drive system, types, structures, cooling systems and interfaces of the traction motors are presented on this paper. Furthermore, the development of other countries on the electric equipments of the next generation railway vehicles are discussed and the necessity ＆ requirement for developing new concepts of traction motors are assured.

• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.51-56
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• 2002

A Korea next-generation high-speed rail system represents a typical example of large- scale multi-disciplinary systems, consisting of subsystems such as train, electrical hardware, electronics, control, Information, communication, civil technology etc. The system design and acquisition data of the large-scale system must be the subject under strict configuration control and management. The system therefore, must be developed using systems engineering that is a efficient and effective methodology to design such a complex system and manage its development. This paper presents the results from a computer-aided systems engineering application to the Korea next generation high-speed railway project. Especially, the focus of the study was on requirement management and PBS management.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.1947-1953
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• 2008

This paper studies a system design of testifying next generation convergence network. Next generation convergence network includes such elements as not only various gateway systems interworking with conventional PSTN(Public Switched Telephone Network) but also various protocols communicating between gateway systems and softswitches or gateway controllers. Discussed are an effective system solution to verify functionalities and performance of protocols professing. From such discussion, the study identifies functional blocks and operational flows required for establishing a test system, and then with a basis of these proposes a system architecture. Finally this paper presents system design results and its implemented functional details.

• Journal of Communications and Networks
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• v.7 no.2
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• pp.115-125
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• 2005

This paper discusses how to effectively design a next-generation wireless communication system that can possibly provide very high data-rate transmissions and versatile quality services. In order to accommodate the sophisticated user requirements and diversified user environments of the next-generation systems, it should be designed to take an efficient and flexible structure for multiple access and resource allocation. In addition, the design should be optimized for cost-effective usage of resources and for efficient operation in a multi-cell environment. As orthogonal frequency division multiple access (OFDMA) has turned out in recent researches to be one of the most promising multiple access techniques that can possibly meet all those requirements through efficient radio spectrum utilization, we take OFDMA as the basic framework in the next-generation wireless communications system design. So, in this paper, we focus on introducing an OFDMA-based downlink system design that employs the techniques of hybrid multiple access (HMA) and frequency group (FG) in conjunction with intra-frequency group averaging (IFGA). The HMA technique combines various multiple access schemes on the basis of OFDMA system, adopting the multiple access scheme that best fits to the given user condition in terms of mobility, service, and environment. The FG concept and IFGA technique help to reduce the feedback overhead of OFDMA system and the other-cell interference (OCI) problem by grouping the sub-carriers based on coherence band-widths and by harmonizing the channel condition and OCI of the grouped sub-carriers.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.190-195
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• 2009

Since the industrial revolution, the global environmental problems such as greenhouse gas accumulation and the average temperature increase have caused people's attention. 'Low Carbon, Green Growth' was presented to cope with these global concerns, as one of main policies of 2008 in Korea. The paradigm of a green urban development is started to concern the whole city's energy problems owing to realize 'Low Carbon, Green Growth' in the urban side. The government established a nation's basic energy plan for 20 years, and some local cities made efforts to develop new renewable energy such as the solar, wind and water energy which are suitable to each city's character. As a part of these efforts, the concept of U-Eco city is newly appeared to reflect upon ubiquitous technique, urban ecology and the next generation energy system. However, urban plan is difficult to adopt this next generation energy system with existing laws, regulations and technical systems. The new executive and systematic system is needed to realize the U-Eco city U-Eco for the management of an efficient city. In this study, the authors investigate the concept of the next generation energy system and U-Eco city to realize the energy-efficient city plan and analyze problems to occur during the application of them in an existing city plan. Then, the authors show the remedies to deal with occurred problems.

• Journal of Satellite, Information and Communications
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• v.10 no.3
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• pp.62-67
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• 2015

This paper we introduce next-generation VSAT system based on DVB-RCS2 which is second-generation satellite communication standard. We construct a test-bed for the functional verification of return link modem and discuss the results. According to this, we expect to efficient use of technology for the next-generation VSAT services and broadcasting services.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.8
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• pp.70-77
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• 2010

This paper presents the current and speed controller design procedure and their performance for the IPMSM based next generation high speed railway traction system. The next generation high speed railway system is a power distributed type and uses vector control method for a motor speed control. Since the speed and current controller gains of the vector control system directly affects to the transient characteristics and speed control capability, the systematic design of the controllers are required. In this paper the controllers are designed using the IPMSM based next generation high speed railway system parameters. Simulation programs based on Matlab/Simulink is developed. Finally the controller characteristics are analyzed by the simulation results.