• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06b
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• pp.115-121
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• 1996

Interactive CATV system is under development to provide multimedia applications such as movies on demand, home shopping, etc. In addition to the conventional analog cable TV services. This system applies international standard DAVIC, ATM forum, DSM-CC etc. The system adopts modular architecture design approach so that the system can be adaptive to the fast moving technology wavefront. In this article, interactive CATV system and essential elements such as video server, delivery network and Set-Top-Box(STB) and related international standardization are introduced.

• Journal of Korean Society for Quality Management
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• v.25 no.4
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• pp.168-184
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• 1997

The primary objective of this paper is to develop an interactive computer graphic aided decision su, pp.rt system for the design of inspection plans for complex production systems. This research first develops a computer simulator, called Simulator for Inspection Systems(SIS), in order to represent the production system as a network model. The simulator elicits fundamental information about the system from the decision maker(DM) in an interactive manner. A decision su, pp.rt system is then proposed by combining SIS and Compromise Programming. The system simulates a set of possible inspection strategies implicitly, observes all the important measurements about the inspection system, and employs the compromise programming a, pp.oach to help the DM determine the best compromising allocation of inspection effort considering his/her preferences. Finally, the performance of the proposed system is evaluated using two test cases. The pros and cons of the system are also discussed.

• Proceedings of the KIEE Conference
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• 2000.11b
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• pp.381-383
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• 2000

The photovoltaic power generation system has a great future as clean energy instead of fossil fuel which has many environmental problems such as exhausted gas or air pollution. In a utility interactive photovoltaic generation system, a three-phase inverter is used for the connection between the photovoltaic array and the utility. This paper presents a three phase inverter for photovoltaic power system with current controller, voltage controller, PLL control system and the phase detector of interactive voltage by using da transformation. The proposed inverter system provides a sinusoidal ac current for domestic loads and the utility line with unity power factor. The results of the operated from January to October show the system characteristics.

• Archives of design research
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• v.16 no.4
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• pp.5-14
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• 2003

This study suggest the development and application of the Interactive Design Toolkit as a participatory design method for general customer who are non-expert on design activity to participate in design process of mass customization. In order to let general customers to express their design needs, we have to make a familiar and direct communication method for them. And, customer's design needs should be transformed into digital media. This study define the Interactive Design Toolkit as a design tool for customer participation by direct manipulation of computer system for simulation of design needs by customer themselves. The Interactive Design Toolkit is based on a PC-based image perception system and its application. User can make virtual models in virtual space by manipulating physical objects in real world. And, The toolkit can be used in the field of participatory design for deliverer side customization, especially in system kitchen which is manufactured and distributed in modular system. More improved design toolkit for manipulating 3 dimensional shape is needed for consumer product design and car styling.

• Journal of Korea Society of Industrial Information Systems
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• v.15 no.2
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• pp.31-39
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• 2010

VoD(Video-on-Demand) servers have to provide timely processing guarantees for continuous media and reduce the storage and bandwidth requirements for continuous media. The compression techniques make the bit rates of compressed video data significantly variable from frame to frame. A VoD system should be able to provide the client with interactive operations such as fast forward and fast rewind in addition to normal playback of movie. However, interactive operations require additional resources such as storage space, disk bandwidth, memory and network bandwidth. In a stored video application such as VoD system, it is possible that a priori disk access patterns can be used to reserve the system resources in advance. In addition, clients of VoD server spend most of their time in playback mode and the period of time spent in interactive mode is relatively small. In this paper, I present the new buffer management scheme that provides efficient support for interactive operations in a VoD server using variable bit rate continuous media. Simulation results show that our strategy achieves 34% increase of the number of accepted clients over the LRU strategy.

• Journal of Korea Game Society
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• v.9 no.3
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• pp.139-150
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• 2009

This paper attempts to investigate the establishment of an interactive knowledge base for action planning by virtual agents and an interactive knowledge-based planning system. A fixed knowledge base is unable to properly handle a change in circumstances because fixed planning is only available under a fixed knowledge base. Therefore, this paper proposes the establishment of an interactive knowledge base which is applicable to diverse environments and an artificial intelligence planning system in which an interactive knowledge base is available. The interactive knowledge base proposed in this paper consists of motivation, behavior, object and action. The association relationship between knowledge base and its input is set using an automation tool. With this tool, a user can easily add to or amend the components of the knowledge base. With this knowledge base, a character plans all action items and chooses one of them to take an action. Since a new action can be applicable by updating the knowledge base even when the character environment changes, it is very useful for virtual reality content developers. This paper has established a relationship between scalable interactive knowledge base components and other components and proposes a convenient input tool and a planning system algorithm effective for an interactive knowledge base. The results of this study have been verified through testing in a virtual environment ('virtual library').

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.3
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• pp.207-221
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• 2014

Education environment of modern society is rapidly changing along the usage of various device and development of contents. Learners of diverse age groups and genders are exposed in smart education environment. Thus in order to investigate effective smart education contents production, this study classified interactive types that affect learning satisfaction into CAI (Computer Assisted Instruction) based , NCS (Network Communication System) based , and NTS (New Technology System) based . Then we investigated how each interactive types affect immersion, utility, self-efficacy, practicality, and stimulation. The effects were measured according to the learner's gender and age. As the result, interactive types do affect smart education, where male had higher learning satisfaction for CAI based, game type, and wiki type while female had higher satisfaction for relationship establishment type and experience type. Also, for age group, the 10s preferred NTS based, 20~30s NCS based, and 40s and over CAI based interactive type. Thus, if satisfaction levels according to gender and age are considered when producing smart education contents, it may be possible to create educative contents that meet the dispositions of the learners.

• ETRI Journal
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• v.35 no.1
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• pp.69-79
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• 2013

For real-time interactive multimedia operations, such as video uploading, video play, fast-forward, and fast-rewind, solid state disk (SSD)-based storage systems for video streaming servers are becoming more important. Random access rates in storage systems increase significantly with the number of users; it is thus difficult to simultaneously serve many users with HDD-based storage systems, which have low random access performance. Because there is no mechanical operation in NAND flash-based SSDs, they outperform HDDs in terms of flexible random access operation. In addition, due to the multichannel architecture of SSDs, they perform similarly to HDDs in terms of sequential access. In this paper, we propose a new SSD-based storage system for interactive media servers. Based on the proposed method, it is possible to maximize the channel utilization of the SSD's multichannel architecture. Accordingly, we can improve the performance of SSD-based storage systems for interactive media operations.

• Journal of Power Electronics
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• v.15 no.6
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• pp.1628-1639
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• 2015

Line-interactive uninterruptible power supply (UPS) systems are good candidates for providing energy storage within a microgrid. In this paper, a control scheme for a line-interactive UPS system applied in a low-voltage microgrid is presented. It is based on the Q-w and P-E droop control to achieve a seamless transition between grid-connected and stand-alone operation modes. Moreover, a new model for designing the controllers is built in the dq-frame based on the instantaneous power definition. The new-built model takes into account the dynamic performance of the output impedance of the inverter in the dq-frame and can be evaluated in the time domain. Compared to the traditional model based on the instantaneous power definition, the new-built model is more accurate to describe the dynamic performance of the system. Simulation and experimental results obtained with a microgrid consisting of two 40-kW line-interactive UPS systems are given to validate the control strategy of the line-active UPS system and the accuracy of the new-built model.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.7
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• pp.70-76
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• 2012

In general, the unidirectional power flow is normal in distribution feeders before activation of distributed power source such as PV. However, the interactive power flow is likely to occur in case of the power system under distributed generation. This interactive power flow can cause an unexpected effect on convectional protection coordination systems designed based only on the unidirectional power flow system. When the power line system encounters a problem, the interactive power flow can be a contributed current source and this makes the fault current bigger or smaller compared to the unidirectional case. The effect of interactive power flow is varied depending on the location of the point to ground fault, relative location of the PV, and connection method. Therefore it is important to analyse characteristics of fault current and interactive flow for various transformer connection and location of the PV. This paper proposes a method of improved protection coordination which can be adopted in the protective device for customers in distribution feeders interconnected with the PV. The proposed method is simulated and analysed using PSCAD/EMTDC under various conditions.