• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.4
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• pp.278-286
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• 2008

This paper investigates the fault generation type and the cause of output interruptionsin bulky with $30^{\sim}500[KVA]$ double conversion UPS, and proposes the fault detection method to improve the reliability of power supply used in the critical load in industry. Identifies its existing way of detecting a quality of inverter output it to bypass when exceeds its expectation. Under a UPS managing system, when an inner (Power device, Controller, CPU) fault occurs it disrupts the power supply and these occurrences has been verified by the results of experiments and application results. To overcome these problems, the proposed method constructs independently a fault-detection, a bypass-control device and a triple power supply apart from the conventional UPS operation. Also the detection point is changed to the preceding of a circuit breaker, a reference of fault detection is modified to avoid any clash and the breaking equipment is attached to intercept a spread of accident. As a result of applications of these developed systems to 242 UPS which was installed purposefully to the communication power supply, the service errors has not occurred in the UPS for two years since 2006.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.4
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• pp.67-73
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• 2002

There have been increased concerns on mobile stratospheric communication system(SCS) for the purpose of advanced service of personal and high speed communication systems. In fact, this SCS is considered and studied for IMT-2000 service by ITU. Although, it is important to make accurate channel model for prediction of the SCS performance, there is no measured channel data in this system. Thus, in this paper, we estimate the performance of SCS bye use of channel model provided by Corazza(2) and modified by You(3). And also, the effects of channel codings on system performance are analyzed by deriving bit error performance based on realistic Rician log-normal fading channel models. The performance results are divided into three kinds of areas with three kinds of elevation angles 20$^\cire$, 45$^\cire$, and 80$^\cire$. And also the effects of forward error correction channel codings on system performance with Hamming(7,4), HCH( IS,7) and convolutional code of constraint length 3 and code rate R=1/2.

• Journal of the Korean association of regional geographers
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• v.12 no.3
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• pp.382-391
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• 2006

The aim of this research is to classify the 21 container ports in European Union countries using components of competition and co-operation under the well-known methodology, FCM(Fuzzy C-Mean). Through this approach, those 21 ports were classified into six poet groups, and also membership degree of each port within the six port groups were suggested. As results, Rotterdam which positioned Group C, is turned out the most competitive independent port. The next competitive group is found out as Group B which consisted of port of Hamburg and Antwerp. In another point of view, Group A and B which have six and four ports respectively, were needed to search the co-operation strategies. Finally, the lowest competitive port groups in the targeted area were shown as Group D and F.

• Journal of Broadcast Engineering
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• v.6 no.3
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• pp.260-269
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• 2001

This paper proposes an efficient algorithm extracting anchor ranges that exist in news video for the unit structuring of news. To this purpose, this paper uses anchors face in the frame rather than the cuts where the scene changes are occurred. In anchor range, we find the end position (frame) of anchor range with the FRFD(Face Region Frame Difference). On the other hand, in not-anchor range, we find the start position of anchor range by extracting anchors face. The process of extracting anchors face is consists of two parts to enhance the computation time for WPEG decoding. The first pact is to find candidates of anchors face through rough analysis with partial decoding MPEG and the second part is to verify candidates of anchors face with fully decoding. It is possible to use the result of this process in basic step of news analysis. Especially, the fast processing and the high recall rate of this process are suitable to apply for the real news service.

• Journal of Broadcast Engineering
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• v.23 no.2
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• pp.261-273
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• 2018

As progress on image processing, computer vision and display technologies aroused market's interests on generation and consumption of various types of media, interests on UWV media are also increasing. In context of consumption of UWV media, to effectively manage load of servers and resources of end terminal devices and provide user-derived services, technology which enables users to select and consume interested regions of media seems to be needed. Here, this paper proposes a method for description and transmission of spatial relationships among media, which composes UWV, by expanding MPEG-CI and Layout signaling to enable users' selective consumption of UWV media.

• Journal of KIISE:Databases
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• v.36 no.3
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• pp.215-225
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• 2009

Recently, various methods have been proposed to process k-NN (k-Nearest Neighbors) queries efficiently. However the previous methods have problems that they access additional cells unnecessarily and spend the high computation cost to find the nearest cells. In this paper, to overcome the problems, we propose a new method to process k-NN queries using the patterns of the distance relationship between the cells in a grid. The patterns are composed of the relative coordinates of cells sorted by the distance from certain points. Since the proposed method finds the nearest cells to process k-NN queries with traversing the patterns sequentially, it saves the computation cost. It is shown through the various experiments that out proposed method is much better than the existing method, CPM, in terms of the query processing time and the storage overhead.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.235-242
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• 2005

As the demands in a wireless network are recently increasing, it is necessary to promote the power efficiency of a wireless terminal, and to reduce the overhead of a network. To resolve such problems, we propose the paging technology and the structure of paging area with the joint access point in HPi (High-speed Portable Internet) network, which is being studied as the domestic next-generation IP packet data network. The application of the paging technology to the HPi network possesses the advantage of reducing the registration cost while a terminal in dormant state moves around, and the reporting cost of the terminal's location by the joint access point. The technology suggested in this paper causes the advantages that it promotes the power efficiency in user's point of view while it reduces the network overhead and makes the easy rearrangement of joint APs according to the changes of users' moving pattern in the network manager's point of view.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.411-413
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• 2010

The wireless AP positioning system is under active progress regarding research and commercialization due to its merit of being able to overcome the representing demerits of existing GPS positioning, which are signal distortion and poor signal reception. This system's feature is to collect AP information distributed throughout the real world, store it on database, and execute positioning by comparing with searched AP information. The positioning process uses collected data, whereas comparison of database data uses the fingerprinting method. The fingerprinting method is a probabilistic modeling method that acquires as much of the data collected from one location upon database composition, to store the value's average value and use it in positioning. Yet, using the average value may contain the probability of errors. Such errors are fatal weaknesses for services based on the background of accurate positioning. This paper deals with the characteristics and problems of the previously used wireless AP positioning system, and proposes measures of using AP information for outdoor positioning in order to solve the aforementioned problems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.7
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• pp.1344-1356
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• 2009

The DDS (Data Distribution Service) is a data-centric communication technology that provides an efficient communication service that supports a dynamic plug & play through an automatic setting of participants' location information for each data (Topic) by using DDS discovery technique. This paper proposes the hierarchical-structured DDS discovery technique (SPDP-TBF) suitable for the large-scale distributed systems by comparing and analyzing the existing DDS discovery techniques in terms of performance and problem areas. The proposed SPDP-TBF performs the periodic discovery of the involved participants only by having separate hierarchical managers which take charge of the registration and search (of participants) so that a participant sends its information to the related participants only, and it enhances the effectiveness of the message transfer. Moreover, the proposed SPDP-TBF provides the improved scalability by performing the hierarchical discovery through hierarchical manager nodes so that it can be applied to the large-scale distributed system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.11
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• pp.2155-2161
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• 2016

Since Korea is highly dependent on energy imports, it has been making efforts to save energy resources by enacting laws to promote resource saving and recycling. Recently, as a part of recycling of empty bottles, a bottle unattended collecting machine has been installed in the big shopping mall in the metropolitan area. However, there is no commercialization of the unattended collecting machine in Korea and the smart device application for providing information on empty bottle recycling is not yet provided. In this paper, we have designed and constructed a bottle recycling information management system to promote resource recycling. The manager has built a homepage that can manage the information of the empty bottle and the a bottle unattended collecting machine. Also, many people with smart devices can easily access bottle recycling information by using camera and barcode search and label search.